According to one embodiment of the present disclosure, an electronic device may include a display and a processor electrically connected to the display. The processor may be configured to classify a frame of content that is being reproduced on the display into a plurality of blocks including at least one pixel, confirm average brightness values of each of the plurality of blocks, determine whether to satisfy at least one specified condition based on the average brightness values of at least some of the plurality of blocks, and adjust brightness of the at least one pixel included in the plurality of blocks if it is determined that the at least one specified condition is satisfied. Other various embodiments may be directed to an electronic device or a method of display content of an electronic device.

Various electronic devices such as a smart phone, a tablet PC, a portable multimedia player (PMP), a personal digital assistant (PDA), a laptop personal computer (PC), and a wearable device may provide various functions (for example, social network service (SNS), internet, multimedia, photograph and performance of photo moving images) as well as a telephone function. In particular, various electronic devices provide a function of reproducing content (for example, media moving image).
Users watch content using an electronic device under various living environments. Accordingly, the electronic device provides a function of automatically or manually controlling brightness of a display depending on the surrounding environment. However, the existing electronic devices may uniformly control the brightness of the display, or the like independent of content.

Electronic device and method for displaying content thereof


A light generating circuit is implanted in a subject's body and aimed at a target region such as a tumor. A photosensitizer is introduced into the target region, and an AC electric field is induced in the region. The field causes the light generating circuit to generate light, which activates the photosensitizer; and at certain field strengths and frequencies, the field itself has a beneficial effect. The beneficial effects of the field and the activated photosensitizer are thereby obtained simultaneously.

Drugs and radiation therapy are conventional approaches to treating cancer. One example is Cisplatin or cis-diamminedichloroplatinum(II) (CDDP), which is a platinum-based chemotherapy drug used to treat various types of cancers, including sarcomas, some carcinomas (e.g. small cell lung cancer and ovarian cancer), lymphomas and germ cell tumors. It was the first member of its class, which now also includes carboplatin and oxaliplatin. Cisplatin acts by crosslinking DNA in various different ways, in a manner that is not cell cycle specific, making it impossible for rapidly dividing cells to duplicate their DNA for mitosis. The damaged DNA sets off DNA repair mechanisms, which activate apoptosis when repair proves impossible.
Another example is Paclitaxel, more commonly referred to by the trade name Taxol®, which is a member of the larger family of compounds known as taxanes. Currently, paclitaxel is used in the treatment of breast, ovarian, certain non-small-cell lung cancers, and Kaposi's sarcoma. This potent anti-neoplastic drug; binds to the N-terminal region of β-tubulin and promotes the formation of highly stable microtubules that resist depolymerization, thus preventing normal cell division and arresting the cell cycle at the G2/M phase. The microtubule damage induces apoptosis through a JNK-dependent pathway in the early phase followed by a JNK-independent pathway, perhaps related to the activation of protein kinase A or of Raf-1 kinase, that results in phosphorylation of Bcl-2. Major metabolite in human liver microsome is 6α-hydroxypaclitaxel (6α-OHP). This enzymatic conversion can be used as a potential marker reaction for human CYP2C8.
An additional cancer treatment modality that has been introduced recently is Photo-Dynamic Therapy (PDT). PDT is a rapidly growing area of medical treatment. The diseases that can be successfully treated by PDT include skin cancer, brain tumors, tumors under the surface of the skin, and tumors located on the lining of internal organs. Photodynamic Therapy involves the use of light-activated dyes (photosensitizers) that preferably localize in target cells (e.g. in tumors) but not in normal, healthy cells. Photosensitizers utilize energy from treatment light to produce a cytotoxic oxygen species which kills cancerous or diseased cells. This toxic oxygen species is not a radical but is actually an excited state of oxygen. The excited state is more reactive than ordinary oxygen, and the atoms are in a different quantum spin state than is normally the case. PDT may also work by destroying the blood vessels that feed the cancer cells and by helping the immune system to attack the cancer.
PDT, using the drug Photofrin®, has now been approved as a therapy for a limited number of applications in various parts of the world including the UK and it is now clear that there are some indications where PDT is at least as good as and possibly better than alternative treatments. However it has to be emphasized that PDT is still largely an experimental therapy and is currently only applicable to a very small range of patients. This limitation results in part from the fact that most tumors are located in areas where light from external sources is not effective. To overcome this problem catheters, having light sources at their tip, are inserted through the skin (or a natural cavity like the GI tract) into the body.
Depending on the part of the body being treated, the photosensitizing substances are either injected intravenously into the diseased area or applied to the skin. The photosensitizer selectively accumulates in the tumor region. After allowing time for the accumulation to occur, a light source is applied to the area to be treated. The light causes the drug to react with oxygen, which forms a chemical that kills the cancer cells. Because blood and melanin are relatively absorptive in the shorter visible wavelengths, it is preferable to use infrared light. Therefore, the ideal photosensitizer has an absorbance peak in the infrared part of the spectrum. This ensures that light used in the treatment is able to penetrate maximally through healthy tissue to arrive at the tumor. However, other wavelengths can be selected according to the absorption and sensitivity of the various substances used.
Light-emitting diodes (LEDs) are considered an appropriate light source for PDT. LEDs have a relatively narrow bandwidth (usually 20 to 30 nm), and are available in a wide range of wavelengths, including the near infrared (NIR) and infrared (IR)—from 650 nm to 950 nm. The flexibility provided by chip-on-board techniques makes it possible to fabricate customized LED illuminators for various PDT applications.
In more established Photodynamic Therapy treatments, such as skin cancer therapy, the diseased zone is exposed to an LED area light for a precisely calculated exposure time. In newer or more experimental areas of treatment, miniature LED arrays are actually implanted into tissue, or are placed on catheters and are moved through the body. In some procedures, LED dice are fixed to a flexible, compact substrate. However, for any tumor situated more than about 1 cm away from the accessible surface, the light source must be implanted. Since LEDs must be hooked up to a power supply in order to function, this generally requires that lead wires connect the LED or other light source to an external device. As the duration of an effective treatment may be long, even weeks, the wires that penetrate the skin may lead to contamination, dysfunction and significant discomfort.

Treating cancer using electromagnetic fields in combination with photodynamic therapy


A method for reconstructing an image of an object includes unwrapping a reduced field of view image, and estimating edge boundaries using the unwrapped reduced field of view image. The estimated edge boundaries are used to calculate the number of aliasing replicates in the reduced field of view image. The number of aliasing replicates is used to unwrap the reduced field of view image.

This invention relates to imaging methods and systems. More particularly, the invention relates to a method and system for image reconstruction.
When a substance such as human tissue is subjected to a uniform magnetic field (polarizing field B0), the individual magnetic moments of the spins in the tissue attempt to align with this polarizing field, but precess about it in random order at their characteristic Larmor frequency. If the substance, or tissue, is subjected to a magnetic field (excitation field B1) which is in the x-y plane and which is near the Larmor frequency, the net aligned moment, Mz, may be rotated, or "tipped", into the x-y plane to produce a net transverse magnetic moment Mt. A signal is emitted by the excited spins after the excitation signal B1 is terminated, this signal may be received and processed to form an image.
When utilizing these signals to produce images, magnetic field gradients (Gx Gy and Gz) are employed. Typically, the region to be imaged is scanned by a sequence of measurement cycles in which these gradients vary according to the particular localization method being used. The resulting set of received NMR signals are digitized and processed to reconstruct the image using one of many well known reconstruction techniques.
One method of acquiring an NMR data set from which an image can be reconstructed is known as the "spin-warp" technique, which is a variant of the well known Fourier transform (FT) imaging technique. The spin-warp technique is discussed in an article entitled "Spin-Warp NMR Imaging and Applications to Human Whole-Body Imaging" by W. A. Edelstein et al., Physics in Medicine and Biology, Vol. 25, pp. 751-756 (1980). It employs a variable amplitude phase encoding magnetic field gradient pulse prior to the acquisition of NMR spin-echo signals to phase encode spatial information in the direction of this gradient. In a two-dimensional implementation (2DFT), for example, spatial information is encoded in one direction by applying a phase encoding gradient (Gy) along that direction, and then a spin-echo signal is acquired in the presence of a readout magnetic field gradient (Gx) in a direction orthogonal to the phase encoding direction. The readout gradient present during the spin-echo acquisition encodes spatial information in the orthogonal direction. In a typical 2DFT image acquisition, a series of pulse sequences is performed in which the magnitude of the phase encoding gradient pulse Gy in the pulse sequence is incremented (ΔGy). The resulting series of views that is acquired during the scan form an NMR image data set from which an image can be reconstructed. The acquisition of each phase encoded view requires a finite amount of time, and the more views that are required to obtain an image of the prescribed field of view (FOV) and spatial resolution, the longer the total scan time.
Many technical developments in the field of MR imaging aim to reduce data acquisition time. One such technical development is known as parallel imaging, in which multiple receive coils are used to reduce scan time.
In parallel imaging techniques, the reduction in scan time comes from omitting k-space lines or, equivalently, spacing the lines further apart. However, the reduction in k-space lines has the effect of reducing the FOV, thus producing image wrapping or aliasing if the object extends outside the reduced FOV in the phase encoding direction.
The aliasing associated with parallel imaging may be eliminated using one of two general techniques. In one technique, the missing k-space lines are synthesized using the receive coil sensitivity (B1 field) spatial information, followed by a Fourier transform to reconstruct an image without aliasing. This technique is called SiMultaneous Acquisition of Spatial Harmonics (SMASH), and is described by Sodickson, et al., "Simultaneous Acquisition Of Spatial harmonics (SMASH)", Magnetic Resonance In Medicine 1997,38:591-603. In a second technique, the aliased images reconstructed from each coil are combined using the receive coil sensitivities to cancel the aliasing. This technique is called sensitivity encoding (SENSE) and is described by K. P. Pruessmann, et al., "SENSE: Sensitivity Encoding for Fast MRI", Magnetic Resonance in Medicine 42, 952-962 (1999). Although these are the two most common parallel imaging methods, other generalized parallel imaging methods combine aspects of both techniques.
In the SENSE technique, the idea is to reduce acquisition time by increasing the step size (ΔGy) between phase encoding views, or equivalently, by reducing the FOV. In either case, the total number of views is reduced with a consequent reduction in scan time. If the object extends outside the reduced FOV, however, aliasing or wrap-around occurs in the phase encoding direction. The SENSE technique removes this aliasing by using knowledge of the surface coil receive field (also called sensitivities) to find the unaliased spin distribution. This knowledge is obtained by performing a sensitivity calibration scan prior to the reduced FOV (SENSE) scan. For example, the sensitivity calibration data may be obtained using combined signals from the surface coils as described in co-pending U.S. patent application Ser. No. 09/851,775 filed on May 9, 2001 and entitled "Calibration Method For Use With Sensitivity Encoding MRI Acquisition".
During both the SENSE scan and the calibration scan, the patient may be required to hold his or her breath to minimize respiratory motion artifacts. If the patient and/or coil move in the phase encoding direction between the calibration and SENSE scans, for example if the patient were to intake a different volume of air during each of the scans, artifacts due to uncorrected aliasing can result.
One method of reducing artifacts due to patient motion between the calibration and SENSE scans is to extend the sensitivity measurement outside the boundaries of the object boundaries detected in the calibration scan using, for example, linear extrapolation. In conjunction with extending the sensitivity, the object boundaries are also extended to be outside those measured in the calibration scan. If the sensitivity and edges are extended sufficiently far, the sensitivity will be estimated at all pixels within the object at its position during the SENSE scan, and in addition, the number of aliased replicates will be greater than or equal to the actual number of replicates at all pixels. For typical scan prescriptions and typical respiratory motion, it has been found that edge and sensitivity extension by 10 to 20 pixels is sufficient. This enables accurate aliasing unwrapping at all pixels, even if the object moved after the calibration scan. However, the final image noise will be higher at pixels where the number of aliased replicates is overestimated. The increased noise frequently covers a large enough area to be noticeable and objectionable.
If the number of aliased replicates is overestimated, an adaptive, pixel-dependent regularization of the SENSE reconstruction has been used to reduce image noise. Adaptive regularization is a well-known numerical method used to reduce noise in the solution of inverse problems. However, one drawback to adaptive regularization is that it requires much iteration to determine the optimum regularization and therefore requires a long reconstruction time.
Another method of reducing artifacts due to patient motion between the calibration and SENSE scans is to combine both scans while the patient holds a single breath. Yet another method of reducing artifacts due to patient motion between the calibration and SENSE scans is to allow the patient to breathe freely while taking multiple averages during the calibration scan. These methods, however, increase the SENSE scan time, thus partially negating some of the advantages of the SENSE technique.

Method and system for image reconstruction

GE Medical Systems Global Technology Company, LLC


A method of forming a silicon carbide ceramic material without forming large areas of a feathered alpha silicon carbide microstructure is disclosed. Basically, the method involves heating the silicon carbide material to a temperature in a range from about 1850.degree. C. to about 1920.degree. C., preferably about 1900.degree. C., and maintaining the material at the selected temperature for a period of time from about 6 hours to about 12 hours. Such a heating cycle produces silicon carbide ceramic material which does not have large areas of a feathered alpha silicon carbide microstructure therein.

Since at least 1974, the General Electric Corporation has worked in the area of making bodies of silicon carbide material by pressureless sintering techniques. Basically, they have proposed that one begin the manufacture of such bodies using submicron beta silicon carbide powder. That powder may be subjected to an operation to form it into a consolidated mass, for example, a slip casting operation or a pressing operation. After the submicron beta silicon carbide powder is consolidated, General Electric has taught that the material should be heated to a temperature in excess of 2000.degree. C. for a period of time of about 1 hour in order to achieve a sintering of the individual beta silicon carbide particles into a single unitary body.
In a paper entitled "Microstructures of Sintered Silicon Carbide" as reported in Ceramic Microstructures, Proceedings of the 6th International Materials Symposium, Westview Press, Colorado (1977), Messrs. C. A. Johnson and S. Prochazka of the General Electric Corporate Research and Development report, beginning at page 366, that large feathery-like alpha silicon carbide platlet grains are developed when beta silicon carbide powder is sintered together. The paper describes that these feathered grains reduce the strength of the overall body. Their paper also indicates that these platlets are formed by what they believe to be a combination of excessively high temperatures and certain chemical impurities such as aluminum.
In my work in this area, I have found that these enlarged platlets can be avoided in a sintering operation if that sintering operation is carried out under certain conditions to be described herein. Thus, even though the powders which I worked upon had the same impurities as contained in the powders worked on by the General Electric personnel, because the powders came from the same common General Electric source, I can now state that the impurities contained in these powders do not generate the particular feathery microstructure. The particular feathery microstructure is generated solely because of the temperature regime in which the prior art suggested that the sintering of such material be carried out. When this material is heated to a temperature in excess of about 1920.degree. C., a temperature lower than the lowest of 2000.degree. C. suggested in the art, I have found that the feathery microstructure is produced, and is produced in a manner in which substantially large grains of such material are found in the microstructure.

Pressureless method of forming a silicon carbide ceramic material


In one embodiment, a network device determines a set of routes to one or more reachable addresses and also a set of no-routes to one or more non-reachable addresses in a computer network. The routes and no-routes may then be aggregated into one or more reachable route prefixes with one or more corresponding non-reachable no-route prefix exceptions. As such, the aggregated combination of route prefixes and no-route prefix exceptions may be utilized by the network device.

Low power and Lossy Networks (LLNs), e.g., sensor networks, have a myriad of applications, such as Smart Grid and Smart Cities. Various challenges are presented with LLNs, such as lossy links, low bandwidth, battery operation, low memory and/or processing capability, etc. One example routing solution to LLN challenges is a protocol called Routing Protocol for LLNs or "RPL," which is a distance vector routing protocol that builds a Destination Oriented Directed Acyclic Graph (DODAG, or simply DAG) in addition to a set of features to bound the control traffic, support local (and slow) repair, etc. The RPL architecture provides a flexible method by which each node performs DODAG discovery, construction, and maintenance.
Notably, the amount of routing information kept in a network, particularly in LLNs, can become significant. In particular, the size of the routing table and/or the size or number of route advertisements becomes a major concern as the network grows larger. These problems, though found in any network, are especially problematic in constrained networks, where bandwidth is limited and most nodes are highly constrained in terms of memory. Accordingly, routing information can directly impact the scalability of many networks.

Route prefix aggregation using reachable and non-reachable addresses in a computer network


A corrosion measurement system includes a corrosion sensor having a corrosion sensor output related to corrosion due to exposure to a process fluid. A process variable sensor provides a process variable output related to a process variable of the process fluid. Measurement circuitry coupled to the corrosion sensor and the process variable sensor provides an output related to corrosion based upon the corrosion sensor output and the process variable output.

The present invention relates to corrosion of components in various settings. More specifically, the present invention relates to monitoring such corrosion.
Corrosion is the gradual destruction of materials by chemical or other reaction with its environment. Corrosion degrades the useful properties of materials and structures including strength, appearance, and permeability to fluids. Many structural alloys corrode merely from exposure to moisture in air but the process can be strongly affected by exposure to certain substances. Corrosion can be concentrated locally to form a pit or crack, or it can extend across a wide area uniformly corroding the surface.
The field of corrosion measurement, control, and prevention is very broad. Corrosion measurement employs a variety of techniques to determine how corrosive the environment is and at what rate metal loss is being experienced. Some corrosion measurement techniques can be used on-line, constantly exposed to the process stream, while others provide off-line measurement, determined in a laboratory analysis. Some techniques give a direct measure of metal loss or corrosion rate while others are used to infer that a corrosive environment may exist.
The rate of corrosion dictates how long any process plant can be usefully and safely operated. The measurement of corrosion and the action to remedy high corrosion rates permits the most cost effective plant operation to be achieved while reducing the life-cycle costs associated with the operation.
The following list details common corrosion monitoring techniques which are used in industrial applications.                Corrosion Coupons (weight loss measurements)        Electrical Resistance (ER)        Linear Polarization Resistance (LPR)        Galvanic (ZRA) I Potential        Hydrogen Penetration        Microbial        Sand/Erosion
The weight loss technique is the best known and simplest corrosion monitoring technique. The method involves exposing a specimen of material (coupon) to a process environment for a given duration, then removing the specimen for analysis. The basic measurement which is determined from corrosion coupons is weight loss. Corrosion rate can be calculated by dividing the weight loss by material density, coupon surface area, and time of exposure. Coupon monitoring is most useful in environments where corrosion rates do not significantly change over long time periods. However, they can provide a useful correlation with other techniques.
ER probes can be thought of as "electronic" corrosion coupons. ER probes provide a basic measurement of metal loss and the value of metal loss can be measured at any time while the probe is in-situ. The ER technique measures the change in electrical resistance of a corroding metal element exposed to the process. The action of corrosion on the surface of the element produces a decrease in its cross-sectional area with a corresponding increase in its electrical resistance.
The LPR technique is based on electro-chemical theory. A small voltage is applied to an electrode in solution. The current needed to maintain a specific voltage shift (typically 10 mV) is directly related to the corrosion on the surface of the electrode in the solution. By measuring the current a corrosion rate can be derived. The advantage of the LPR technique is that the measurement of corrosion rate is made instantaneously whereas with coupons or ER some period of exposure is required to determine corrosion rate. The LPR technique can only be performed in clean aqueous electrolytic environments and will not work in gases.
Corrosion is an expense in many systems. The impact of corrosion includes lost production, system down time, system failures, as well as repair time and expense. There is an important need to prevent and monitor corrosion.

Corrosion rate measurement with multivariable sensor


A resistance ladder which divides a potential difference between two power sources into 2.sup.m levels by a resistance group in the center portion, then adjusting the number of resistors which are disposed at the both end portions of the resistance ladder and interposed between the resistors of the center portion and the two power sources so that the division voltages of 2.sup.m levels are changed in (n-m) levels, with the result that the potential difference is divided into 2.sup.n levels. A D-A converter uses the resistance ladder. An A-D converter with the D-A converter which generates a reference voltage to be compared with an input voltage.

1. Field of the Invention
The invention relates to a resistance ladder, a D-A converter based on the resistance ladder, and an A-D converter using the D-A converter.
2. Description of the Prior Art
An A-D converter which converts an analog voltage into a digital value requires a reference voltage which is to be compared with a to-be-converted object, i.e., the analog voltage. In a typical A-D converter, an analog reference voltage for comparison is generated by a D-A converter using a resistance ladder in which plural resistors are connected in series.
FIG. 1 is a circuit diagram showing the configuration of main portions of a D-A converter of n-bit resolution which uses a conventional resistance ladder. This prior art example is a D-A converter of 4-bit resolution. In the figure, 1 designates a positive analog voltage source (VREF), and 2 designates a negative analog voltage source (AVSS). A resistance ladder 3 is connected to the positive and negative analog voltage sources 1 and 2. The resistance ladder 3 consists of: a string of resistors 4, 4, . . . in which (2.sup.n -2) [=14] resistors 4 each having a resistance of R are connected in series; a resistor 6 which has a resistance of 3R/2, and through which one end of the string of resistors 4, 4, . . . is connected to the positive analog voltage source 1; and a resistor 5 which has a resistance of R/2, and through which the other end of the string of resistors 4, 4, . . . is connected to the negative analog voltage source 2. The resistance ladder 3 has a total resistance of 16.multidot.R, and divides the potential difference between the positive and negative analog voltage sources 1 and 2 into 2.sup.4 levels. Ladder taps T1 through T16 through which division voltages of 2.sup.4 levels are taken out are connected to the node between the resistor 5 of the resistance ladder 3 and the negative analog voltage source 2, and to the nodes between the other resistors, respectively.
A switching tree 7 comprises a group of switches 70 through 77 which are controlled so as to select one of the ladder taps T1 through T16 of the resistance ladder 3 to obtain an analog output 8. The on/off operations of the group of switches 70 through 77 ace respectively controlled by the levels of digital signals a, a, b, b, c, c, d and d which are supplied from an external control circuit (not shown) through word lines, and which indicate a 4-bit digital value "abcd" by means of positive and negative logic. The switches 70 through 77 are turned on when the digital signal corresponding to the letter assigned to the respective switch in FIG. 1 is "1". In other words, FIG. 1 shows a state that the digital value "abcd" is "1010.sub.2 " or the digital signals a, b, c and d are "1" and the other digital signals are "0".
Table 1 shows the relationship between the digital value "abcd", analog voltages of the analog output 8 in the case where VREF and AVSS are 4 V and 0 V, respectively, and the ladder taps T1 through T16 from which the analog voltages are obtained. As seen also from the table, the ladder taps attain voltages in such a manner that the potential difference between the ladder tap T1 as the lowest tap of the resistance ladder from which the potential of AVSS is obtained, and the ladder tap T2 is 0.125 V, the potential difference between VREF and the ladder tap T16 is 0.375 V, and the potential difference between each adjacent two of the other ladder taps T2 through T15 are 0.25 V. In other words, voltages obtained by dividing the potential difference between VREF and AVSS into 2.sup.4 [=16] levels are taken through the ladder taps T1 through T16, respectively.
FIG. 2 shows a sequential approximation type A-D converter of 4-bit resolution which is disclosed in, for example, Japanese Patent Application Laid-Open No. 54-151368 (1979) (U.S. application Nos. 879,646, 968,329), and which uses the D-A converter of FIG. 1. In the figure, 9 designates a D-A converter of 4-bit resolution having the configuration of FIG. 1. The D-A converter 9 supplies an analog voltage of a 4-bit digital value which is one of the analog voltages obtained from the ladder taps T1 through T16 listed in Table 1, to a comparator 16 as a reference voltage to be compared with an analog input (AIN) 25 supplied from outside. A 4-bit control circuit 10 generates digital signals a, a, b, . . . , d which correspond to the 4-bit digital value, and supplies the digital signals to the D-A converter 9 through word lines. Furthermore, the 4-bit control circuit 10 determines the 4-bit digital value on the basis of a comparison result signal 20 outputted from the comparator 16 which compares the analog input 25 with the analog output 8 of the D-A converter 9.
Next, a digital conversion conducted by the thus configured A-D converter in the case where the analog input 25 is 1.3 V will be described.
First, a digital signal corresponding to a digital value "1000.sub.2 " in which the highest-order bit "a" of the digital value "abcd" is set to be "1" is supplied to the D-A converter 9 in order to output the comparison reference voltage therefrom. The D-A converter 9 then supplies a voltage: EQU (VREF/2)-(VREF/32) [V](=1.875 V)
to the comparator 16. The comparator 16 compares the analog output 8 of the D-A converter 9 with the analog input (AIN) 25 as follows: EQU [(VREF/2)-(VREF/32)]:AIN
i.e., EQU 1.875 V:1.3 V
Since AIN is lower, the 4-bit control circuit 10 determines the digital value of the bit "a" to be "0" in accordance with the comparison result signal 20.
Then, a digital signal corresponding to a digital value "0100.sub.2 " in which the bit "b" is set to be "1" is supplied to the D-A converter 9 which in turn supplies a voltage: EQU (VREF/4)-(VREF/32)[V](=0.875 V)
to the comparator 16. The comparator 16 compares the analog output 8 of the D-A converter 9 with the analog input (AIN) 25 as follows: EQU [(VREF/4)-(VREF/32)]:AIN
i.e., EQU 0.875 V:1.3 V
Since AIN is higher, the 4-bit control circuit determines the digital value of the bit "b" to be "1"in accordance with the comparison result signal.
Then, a digital signal corresponding to a digital value "0110.sub.2 " in which the bit "c" is set to be "1" is supplied to the D-A converter 9. The D-A converter 9 supplies a voltage: EQU (3.multidot.VREF/8)-(VREF/32)[V](=1.375 V)
to the comparator 16. The comparator 16 compares the analog output 8 of the D-A converter 9 with the analog input (AIN) 25 as follows: EQU [(3.multidot.VREF/8)-(VREF/32)]:AIN
i.e., EQU 1.375 V:1.3 V
Since AIN is lower, the 4-bit control circuit 10 determines the digital value of the bit "c" to be "0" in accordance with the comparison result signal.
Then, a digital signal corresponding to a digital value "0101.sub.2 " in which bit "d" is set to be "1" is supplied to the D-A converter 9 which in turn supplies a voltage: EQU (5.multidot.VREF/16)-(VREF/32)[V](=1.125 V)
to the comparator 16. The comparator 16 compares the analog output 8 of the D-A converter 9 with the analog input (AIN) as follows: EQU [(5.multidot.VREF/16)-(VREF/32)]:AIN
i.e., EQU 1.125 V:1.3 V
Since AIN is higher, the 4-bit control circuit 10 determines the digital value of the bit "d" to be "1" in accordance with the comparison result signal.
As a result of the above-mentioned sequential comparison, the analog voltage 1.3 V of the input AIN is converted into a digital value "0101.sub.2 ".
An A-D converter of 9-bit resolution can conduct an A-D conversion twice the accuracy when the resolution is 8-bit. Likewise, an A-D converter of 10-bit resolution can conduct an A-D conversion twice the accuracy of 9-bit resolution. As the resolution becomes higher, therefore, a value indicated by the resulting digital value more approximates an input analog value.
An A-D converter in which an analog reference voltage for comparison is generated by a D-A converter based on a resistance ladder has an advantage in the excellent linear conversion properties because the D-A converter based on the resistance ladder generates an analog reference voltage by using only resistors and therefore the resulting division voltages are correct as far as the resistors are uniformly irregular.
On the other hand, in the A-D converter of the above type, the D-A converter must generate division voltages of the corresponding number to the resolution of the A-D converter. Therefore, an A-D converter of 8-bit resolution requires at least 2.sup.8 [=256] resistors. Similarly, an A-D converter of 9-bit resolution requires at least 2.sup.9 [=512] resistors, and that of 10-bit resolution requires at least 2.sup.10 [=1024] resistors. That is, when the resolution is improved every one bit, the number of resistors must be doubled. Consequently, the A-D converter is disadvantageous in that the improvement of the resolution inevitably increases the device area and impairs the production yield thereby to increase the production cost of an LSI.
In order to eliminate the drawbacks discussed above, an improved circuit is disclosed in, for example, Japanese Patent Application Laid-Open No. 1-97020(1989). In an A-D conversion process conducted by the circuit, two adjacent ladder taps of a resistance ladder string are selected, another resistance ladder string having a resistance which is much higher than that between the above ladder taps is connected to the ladder taps, and the potential across the selected ladder taps is further divided by the resistor string of a higher resistance, thereby improving the resolution of an A-D converter.
Other prior art A-D converters using a D-A converter include a parallel A-D converter, and a serial-parallel A-D converter in which the D-A converter repeats a conversion process every plural bits in a sequence from a high-order bit to the lowest-order bit, and a comparison between an analog output of every plural bits and an analog input to be converted is repeated to conduct a digital conversion.
FIG. 3 is a circuit diagram showing the configuration of a prior art D-A converter which is used in a parallel A-D converter, or a serial-parallel A-D converter to convert a digital value into an analog value per p bits. The illustrated D-A converter of 4-bit resolution conducts an analog conversion per 2 bits. The D-A converter consists of a resistance ladder in which 2.sup.n [=16] resistors are connected in series, (2.sup.p -1) [=3] analog outputs 81, 82 and 83, and 15 selecting switches 701 through 715 which are used for obtaining the (2.sup.p -1) analog outputs 81, 82 and 83 from the resistance ladder. An A-D converter using the D-A converter has (2.sup.p -1) comparators (not shown) which are respectively connected to the analog outputs 81, 82 and 83, and compares an analog voltage input from outside with analog outputs of the D-A converter resulting from the analog conversions per 2 bits from a high-order bit, to convert the analog value into a digital value.
In the case where a resistance ladder having the configuration of FIG. 1 is employed in the above D-A converter, the improvement of the resolution requires an increase of the circuit scale, similar to the foregoing example. When a D-A converter of 6-bit resolution is to be realized in a configuration similar to that of the D-A converter of 4-bit resolution shown in FIG. 3, for example, the resistance ladder must be composed of at least 64 resistors and requires 62 switches.
In the circuit disclosed in Japanese Patent Application Laid-Open No. 1-97020 (1989) (EP Appl. No. 87480013.9), even when the resistors connected between two ladder taps have a very high resistance, the main current passing through the resistance ladder is theoretically shunted, so that the potential difference between the ladder taps to which the group of high resistance resistors is connected is reduced. In this case, the voltage across the ladder taps to which the group of high resistance resistors is connected is not equal to potential differences of the other ladder taps. Therefore, it is substantially impossible to eliminate an error caused by the reduced potential difference.
If the group of high resistance resistors has a resistance as high as 2,000 times the resistance between adjacent ladder taps of a first resistance ladder, an error due to the connection of the group of high resistance resistors can be reduced to an allowable range. However, even when the error can be reduced to an allowable range, when all the resistors are made of the same material, it is apparent that the group of high resistance resistors occupies a considerably large area.
The problem of a large area occupied by the group of high resistance resistors may be solved by using a material of a high resistivity. Theoretically, switches correcting the resistors of the group to the ladder taps may have a resistance. Unless the circuit is designed with due consideration of the resistance of each switch, therefore, it is impossible to correctly divide the potential difference between the reference voltage sources connected to the both ends of the resistance ladder. In order to configure the circuit in due consideration of the resistances of the switches, the switches must exhibit a uniform resistance at any of the ladder taps.
A D-A converter of 4-bit resolution is disclosed in FIGS. 4 and 5 of Japanese Patent Application Laid-Open No. 54-151368(1979) (U.S. application Nos. 879,646, 968,329), and a 12-bit A-D converter to which the D-A converter is applied is disclosed in FIG. 7. In the D-A converter, 3 unit resistors each having a resistance of R, and subsequently 4 resistors each having a resistance of R/4 are connected in series between a positive analog voltage source and a negative analog voltage source, thereby constituting a resistance ladder. Two analog voltages obtained from the group of the 3 resistors and that of the 4 resistors are supplied to non-inverting and inverting inputs of a buffer, respectively, so that an analog output is obtained in accordance with the difference between the two analog voltages.
In the disclosed converter, the resistance ladder is configured by a small number of resistors, and therefore the resistors occupy a small area. Since the number of the resistors is small, however, a total sum of resistances of the resistance ladder is smaller than that of a resistance ladder composed of series resistors. When the impedances of the positive and negative analog voltage sources are not sufficiently low, charging and discharging currents of a capacitance existing in the resistance ladder causes the analog voltage sources to fluctuate in the output level, with the result that the accuracy of the A-D converter is adversely influenced.
Since resistive component of conductors connecting the resistors each other greatly influence the resistance ladder when the whole resistance thereof is low, the resistance ladder should be composed with careful consideration also to the resistive component, which quantity is little, of the conductors.
In an A-D converter of 6-bit resolution using a D-A converter based on a series resistance ladder, there are 64 ladder taps and 64 paths extending between the ladder taps to an analog output through a switching tree. When the continuity of the ladder taps is to be checked, therefore, accuracy at 64 points must be tested while the A-D conversion is conducted.
At the inspection of LSIs before shipment, when an LSI has even a single faulty transistor in the whole circuit, the LSI is selected as a defective one. Generally, an A-D converter, and an LSI loading the A-D converter are subjected also to testing of the conversion accuracy of the A-D converter. If the A-D converter is composed of a resistance ladder, the testing must be conducted by the number corresponding to the resolution of the A-D converter. As the resolution becomes higher, therefore, the number of testing points is increased so that the test time is lengthen, thereby causing the production cost to be increased.

Resistance ladder, D-A converter, and A-D converter


The present application discloses a control device for an ice making machine to make ice by circulating ice-making water to an ice making member having a refrigerating system, said control device comprising a timer circuit to be operated simultaneously with or with a delay after the start of an ice making operation and adapted to control a period of time during which an ice making operation is performed, a temperature sensing element whose impedance varies with the variations of the ambient temperature around the refrigerating system, so that an input voltage applied to the timer circuit may vary with the variations of an impedance of the temperature sensing element, thereby to automatically control the period of time during which an ice making operation is performed, whereby the thickness of ice made when one cycle of an ice making operation is completed, may be maintained constant at all times.. According to the present invention, provision is made so that, if a condenser is clogged with dust or dirt, an indication is given of such clogging.

In a conventional method of making ice by circulating ice-making water to the ice making member having a refrigerating system, a period of time of an ice making operation has been controlled by a timer. According to such a conventional method, when a period of time preset to the timer has been long, ice having a relatively large thickness has been made, and when such preset time has been short, ice having a relatively smaller thickness has been made. However, even if a period of time preset to the timer has been suitable, the thickness of ice made has varied with the ambient temperature. It has therefore been impossible to make ice having a predetermined thickness.


A variable magnification finder optical system is constructed independent of a photographic optical system, and includes an objective optical system of positive refracting power, a field frame, and an eyepiece optical system of positive refracting power. The objective optical system has a variable magnification lens unit for changing the field angle of the variable magnification finder optical system in accordance with a change of the field angle of the photographic optical system and a fixed lens unit, which can be replaced with another fixed lens unit for changing over the finder magnification. Thus, this finder optical system allows the photography of an object with a field image, easy for observation, coordinated with that of the photographic optical system.

1. Field of the Invention
This invention relates to a variable magnification finder optical system which can change a photographic range by converting the dimensions of film onto which an image is photographed into other dimensions and, in particular, to a variable magnification finder optical system which in a camera permitting panoramic photography, changes a finder in association with the conversion of the film size.
2. Description of the Related Art
In recent years, cameras for 35 mm film format have been designed so that a light-blocking plate shielding the upper and lower portions of a film surface is placed in the optical path adjacent to the film surface to laterally enlarge an range in which the image is photographed on a film. In this way, panoramic photography that enhances a wide-screen sensitivity of a photographic picture has been popularized. In most of the finders for cameras provided with such a function, as shown in FIG. 1, a frame (panoramic frame) B indicative of the range in which the image is photographed on the film in the panoramic photography is marked within a field frame A for ordinary photography indicative of the photographic range. Consequently, the problem has been encountered that for a photographer, it is hard to imagine the result of the picture. This is because in ordinary photography, the panoramic frame B overlaps the field frame A and the image to be photographed is difficult to view, while in panoramic photography, other images out of the photographic range will also be visible.
In order to obviate such drawbacks, provision has been made that in the panoramic photograph, the vertical length of the field frame A for ordinary photography is changed and diminished to correspond to that of the panoramic frame B. This, however, has caused the problem that the area occupied by the visual field within the finder becomes smaller and thus the photographer has the impression that the visual field has narrowed.

Variable magnification finder optical system


A method for enhancing signal-to-noise (S/N) ratio of seismic data is presented. An ensemble of input traces is decomposed into a plurality of frequency bands of traces. Trace and signal power and then a maximum allowable signal-to-noise ratio are estimated for each frequency band. Weights are calculated which are functions of the inverse noise power or rms. The amplitudes in each of the traces are reformed using a fitting function which utilizes the estimated weights to create true relative amplitude signal enhanced traces. The weighting function has data adaptive parameters which can be changed to accommodate noise characteristics such coherency, incoherency, Gaussian and non-Gaussian distributions, etc. The method may be applied across many different coordinate systems. The method may be applied iteratively to seismic data to shape the noise distribution of the seismic data.

Seismic data obtained in field surveys include signals from subterranean formations, and also noise. The signals are produced by acoustic reflections or refractions from rock layers below the surface of the earth. Most raw land and marine seismic data closely conform to a reflection signal plus additive and/or convolutional noise model. The noise may be due to a number of sources such as power lines, motor vibrations and animal noise. In marine data, everything from swell, tow and propeller noise to shot generated direct waves, refractions and multiples to shipping, cetacean and other seismic crews act as additive noise relative to a reflected signal. Convolutional noise sources, like source and receiver coupling, processing and system noise are types of noise that also have to be accommodated. The different types of noise compromise the effectiveness of the end results of the processing of seismic data because the noise can overwhelm the signal. In such cases, the signal can be difficult, if not impossible, to interpret and quantify.
Diversity noise attenuation methods were invented in the mid 1960's by Geophysical Services Inc. (GSI) and were successfully used to extract signals from vibroseis sweep data recorded in areas having extreme amounts of cultural noise. The underlying principle of diversity noise attenuation is that seismic data are composed of nearly uniform strength signals and large amounts of additive noise. For vibroseis sweeps, samples are weighted inversely proportional to a local estimate of noise power before being summed with other sweeps. The less power in an arrival, the more likely that the arrival is signal.
Methods for improving the S/N ratio in seismic data are described in numerous patents. For example, one method is taught by U.S. Pat. No. 3,398,396 to Embree. This method utilizes the amplification of each trace as a function of the inverse ratio of the total power in each trace as compared to another trace. The amplified traces are then combined into a group of modified traces. Embree also suggests that input seismic data may be weighted in dependence upon the power in frequency components or bands. The signals, separated based on frequencies, are modulated on a frequency dependent noise based correcting function and are then summed to produce enhanced output traces.
A second method is taught by U.S. Pat. No. 5,138,583 to Wason et al. This method provides for attenuation of coherent and incoherent noise in seismic signals. Seismic signal data are transformed from a time-space domain using a Radon-transform domain. In the Radon-transform domain, coherent noise is attenuated by muting and incoherent noise is attenuated by diversity stacking. Data remaining in the Radon-transform domain are transformed back to the time-space domain by an inverse Radon transform.
Each of these methods has shortcomings. These methods do not produce output trace amplitudes preserving true relative signal amplitude within the total seismic data set. These previous methods approximate noise power with total trace power which incorrectly alters relative signal amplitudes. True relative signal amplitude refers to the changes in signal component of the output amplitude being directly proportional to relative changes in subsurface interface reflection coefficient. Another shortcoming is the restrictions of these methods to certain data coordinates such as common source receiver geometry or Radon data coordinates. Further, weighting schemes in these methods do not provide data adaptive parameterization of noise estimation. There is a need for a method of enhancing the S/N ratio of seismic data which overcomes the shortcomings of the above described methods. The present invention provides a method which addresses this need.

Method for signal-to-noise ratio enhancement of seismic data using frequency dependent true relative amplitude noise attenuation


In order to dilate nasal passages and to increase the ease with which respiration may be carried out through the nose, tape members are adhered to the wearer's face between a location adjacent the nose just below the medial infra orbital region and a location just inferior to the zygomatic ridge. The tape members maintain the nasal concha in a dilated state and markedly reduce the restriction to air flow.

1. Field of the Invention
The present invention related to an article which can be applied to the face of a user to facilitate respiratory activity. More specifically, the present invention relates to an article in form of a tape which can be applied to the face of a user on either side of the user's nose in a manner which opens the nasal concha and therefore reduces nasal air flow restriction and promotes easier breathing. Still more particularly, this invention relates to a method of facilitating respiratory activity.
2. Description of the Related Art
FIG. 1 shows an article 10 which can be applied to the nose in the illustrated manner and which is arranged to gently pull the nostril passages 12 open to dilate them. The article 10 is said to improve the ease with which the wearer can breathe through his or her nose. While this article exhibits certain merits such as being applicable to both athletes and persons who have difficulty breathing at night, it is only able to open the nostril passages. This arrangement is further such that it encounters the drawback that it can possibly interfere with the wearing of sunglasses, goggles or the like such as worn during ski competitions and the like. Accordingly, it remains an objective to improve upon the article 10 as will be seen from a review of this written description of the invention taken with the accompanying drawings.

Method for dilating respiratory passages


1-(Substituted phenyl)-3-(thioimidate)pyrazoles having systemic activity, arthropodicidal (especially insecticidal) and nematocidal compositions comprising same and methods for controlling arthropods (especially insects) and nematodes.

1. Field of the Invention
The invention relates to new 3-(sulfur containing substituent) derivatives of 1-arylpyrazoles and related compounds. The invention further pertains to compositions of said compounds and methods, using said compounds, for the control of arthropod or nematode pests, in particular to the application of said compounds or compositions in agricultural methods of use, particularly as pesticides, for controlling arthropods, especially insects by systemic action.
2. Description of the Related Art
International Patent Publication No. WO 87/03781 and European Patent Publication No. 0295117 describe insecticidal 1-(substituted phenyl) pyrazoles.
International Patent Publications No. WO 93/06089 and WO 94/21606 also describe insecticidal 1-(4-SF.sub.5 substituted phenyl) heterocycles which may be pyrroles as well as imidazoles or pyrazoles. The teaching of these patents is not substantially different from that of International Patent Publication No. WO 87/03781 or from that of European Patent Publication No. 0295117 as far as pyrazoles are concerned.

Pesticidal 1-arylpyrazole-3-carboximidothioic acid esters


An electric arc engine welder includes a housing having a cavity therein. An opening is defined by the housing and is connected to the cavity. A track member is mounted to the housing adjacent the opening. The track member defines at least one slot along a longitudinal extent thereof. Two hooks are connected to a door and are received in the at least one slot for removably mounting the door to the housing. The two hooks are spaced apart from one another a first distance. Two notches are defined in the track member and are connected to the at least one slot. The two notches are spaced apart from one another a second distance that is different than a first distance. The notches allow the door to be removed from the housing.

1. Field of the Invention
The present invention relates to a door assembly and, more particularly, to a slidably removable door assembly. The present invention finds particular application as a side door assembly for use on an electric arc engine welder and will be described with particular reference thereto. However, it is to be appreciated that the present invention may relate to other similar environments and applications.
2. Description of the Art
It is well known to provide doors or openable panels on housings of electric arc engine welders for providing access therein. Access within the housing of an electric arc engine welder allows components contained within the housing to be serviced or replaced when desired. Often, the doors or panels of engine welder housings are adapted to be removable from their respective housings for purposes of allowing the doors or panels to be totally removed as obstructions when desirable to work on one or more of the components contained within the engine welder housing.
One problem with removable doors or panels on engine welder housings is that they may inadvertently separate from the engine welder housing at times when such separation is not desirable. Thus, there is a need for a door assembly that allows a door to be removable from an engine welder housing while eliminating or reducing inadvertent separation of the door from the engine welder housing.


The present invention relates to a compound of general formula (I) which can transport holes in an organic optoelectronic device, and to blends and solutions comprising the compound of general formula (I):

Organic electronic devices provide many potential advantages including inexpensive, low temperature, large scale fabrication on a variety of substrates including glass and plastic. Organic light emitting diode displays provide additional advantages as compared with other display technologies—in particular they are bright, colourful, fast-switching and provide a wide viewing angle. OLED devices (which here includes organometallic devices and devices including one or more phosphors) may be fabricated using either polymers or small molecules in a range of colours and in multicoloured displays depending upon the materials used. For general background information reference may be made, for example, to WO90/13148, WO95/06400, WO99/48160 and U.S. Pat. No. 4,539,570, as well as to "Organic Light Emitting Materials and Devices" edited by Zhigang Li and Hong Meng, CRC Press (2007), ISBN 10: 1-57444-574X, which describes a number of materials and devices, both small molecule and polymer.
In its most basic form an organic light emitting diode (OLED) comprises a light emitting layer which is positioned in between an anode and a cathode. Frequently a hole injection layer is incorporated in between the anode and the light emitting layer. It functions to decrease the energy difference between the work function of the anode and the highest occupied molecular orbital (HOMO) of the light emitting layer thereby increasing the number of holes introduced into the light emitting layer. In operation holes are injected through the anode, and if present the hole injection layer, into the light emitting layer and electrons are injected into the light emitting layer through the cathode. The holes and electrons combine in the light emitting layer to form an exciton which then undergoes radiative decay to provide light.
In many OLEDs the light emitting layer comprises a light emitting compound and a charge transporting material, e.g. a electron transporting polymer. A wide range of light emitting compounds are employed. These are generally metal complexes of lanthanide or d-block metals such as iridium. Typically 40-50% wt of the light emitting layer is light emitting compound and the remainder is charge transporting material. Such devices have excellent optoelectronic properties, namely high luminance, current density and EQE for a given drive voltage as well as luminance over extended periods of time (i.e. extended device lifetime).
The drawback of such devices, however, is that the light emitting compounds, present in amounts of up to 50% wt of the light emitting layer, are expensive and this significantly increases the overall cost of the manufacture of the devices. A need therefore exists for new devices that provide comparable optoelectronic properties to todays commercially available devices but which are less expensive to prepare.

Abstract: wherein        X is C, Si or Ge;        A is a group of formula (II)

Abstract: wherein Z is N, P, NH, O or S;        E is C1-10 alkyl or H;        W is substituted or unsubstituted C5-14 aryl or substituted or unsubstituted C6-16 alkyl;        e is an integer from 1 to 4; and        z is 1 or 2;        B, C and D are each independently A, H, C1-C12 alkyl, C5-14 aryl or OH; anda, b, c and d are each independently an integer from 1 to 5.


A diamond, ceramic, metal, or metal alloy surface is coated with molten Csub.3. The coated surface is then heated in air at a temperature of from about 200.degree. C. to 250.degree. C. until the molten CrO.sub.3 coating is converted into a black, powdery adherent coating of CrO.

This invention relates to metal oxide coatings and more particularly to chromium oxide coatings.
Chromate coatings have been employed widely in corrosion protection of aluminum alloys and steel. Thermal radiation balance, however, is a second possible use.
There have been initiatives in recent years to find coating methods, in general, which reduce (or eliminate, if possible) the quantity of waste products which must be disposed of and volatiles released into the air due to vehicles or solvents used in the process.

Chromic oxide coatings by thermal decomposition of chromic acid anhydride (CrO.sub.3)

The United States of America as represented by the Secretary of the Navy


A device drawing a three-dimensional shape and including a high order bit comparing section comparing high order bits of a depth value retained by a high order Z-buffer memory with high order bits calculated by a calculation section. If these two sets of high order bits are the same, a low order bit comparing section compares low order bits retained by a low order Z-buffer memory with low order bits calculated by the calculation section. If a depth indicated by the high order bits calculated by the calculation section is shallow, the high order bits retained by the high order Z-buffer memory and the low order bits retained by the low order Z-buffer memory are updated. If a depth indicated by the low order bits calculated by the calculation section is shallow, the low order bits retained by the low order Z-buffer memory are updated.

1. Field of the Invention
The present invention relates to a three-dimensional shape drawing device and a three-dimensional shape drawing method, and more particularly to a three-dimensional shape drawing device and a three-dimensional shape drawing method for drawing a three-dimensional shape by using Z buffer algorithm using a depth value from a viewpoint.
2. Description of the Related Art
There have been three-dimensional shape displaying devices for drawing a three-dimensional shape by using a Z buffer algorithm as a hidden surface removal system. Also, there have been techniques for increasing a speed of drawing processing of such a three-dimensional shape displaying device, for example, a technique in which each pixel contains one bit flag memory (e.g., patent document 1) and a technique which uses a degenerated Z buffer for, among a plurality of depth values of pixels, storing a depth value of a farthest pixel from a view point and a depth value of a nearest pixel from the view point (e.g., patent document 2).
FIG. 7 is a block diagram showing a configuration of a three-dimensional shape drawing device 200 described in the patent document 2. FIG. 8 is a diagram schematically showing a screen 214 for displaying a three-dimensional shape drawn by the three-dimensional shape drawing device 200 shown in FIG. 7 and a configuration of a ZR buffer 205.
In FIG. 7, an image supply section 208 supplies, to a pixel drawing section 209 and a drawing determination section 210 of an image composing section 201, data of a polygon (hereinafter, referred to as polygon data) to be drawn. The image composing section 201 converts the polygon data into pixel data.
As shown in FIG. 8, the screen 214 is divided into M×N blocks. A block 213 being a portion of a divided image signal comprises K×L pixels. The ZR buffer 205 retains a MAXZ and a MINZ of each of the blocks.
A Z main buffer 206 stores all Z values (depth values) The ZR buffer 205 retains a maximum Z value (MAXZ) 211 and a minimum Z value (MINZ) 212 of each of the blocks shown in FIG. 8.
The pixel drawing section 209 outputs, to a drawing determination section 210, a Z value of a pixel to be drawn, and also outputs X and Y coordinates indicating a position of the pixel. Based on either only the Z values retained by the ZR buffer 205 or both the Z values retained by the ZR buffer 205 and the Z values retained by the Z main buffer 206, the drawing determination section 210 determines whether or not to draw the pixel.
A frame buffer 203 retains the pixel which has been determined, by the determination section 210, to be drawn. A palette circuit 204 converts data of the pixel retained by the frame buffer 203 into brightness data indicating actual brightness. The palette circuit 204 supplies, to a display section 207, image to be displayed.
When the conventional three-dimensional shape drawing device described in the patent document 2 draws a new three-dimensional shape, the MAXZ 211 and MINZ 212 of the block 213 of the screen 214 are compared with a Z value of the pixel to be newly drawn. If the Z value of the pixel to be newly drawn is greater than the MAXZ 211, the three-dimensional shape drawing device 200 terminates drawing the pixel.
On the other hand, if the Z value of the pixel to be newly drawn is smaller than the MINZ 212, the three-dimensional shape drawing device 200 writes a new Z value in the Z main buffer 206, and writes a new pixel value in the frame buffer 203. Further, the three-dimensional shape drawing device 200 overwrites the MINZ 212 with the new Z value.
If the Z value of the pixel to be newly drawn is between the MINZ 212 and MAXZ 211, the three-dimensional shape drawing device 200 refers to the Z main buffer 206, and compares the Z value of the pixel to be drawn with a Z value retained by the Z main buffer 206.
If the Z value of the pixel to be newly drawn is smaller than the Z value retained by the Z main buffer 206, the three-dimensional shape drawing device 200 overwrites the Z value retained by the Z main buffer 206 with a new Z value. Then, the three-dimensional shape drawing device 200 checks, among the Z values retained by the Z main buffer 206, all Z values belonging to the block 213, and then sets a greatest Z value among all the Z values belonging to the block 213 as the MAXZ 211.
As described above, the conventional three-dimensional shape drawing device described in the patent document 2 accesses the Z main buffer 206 only when the Z value of the pixel to be newly drawn is between the maximum Z value and the minimum Z value of the block in which the pixel is positioned. As a result, the frequency of accessing the Z main buffer 206 is reduced.    [Patent Document 1] Japanese Laid-Open Patent Publication No. 62-42281    [Patent Document 2] Japanese Laid-Open Patent Publication No. 8-161526 (pages 5-7, FIGS. 1 and 4)

Three-dimensional shape drawing device and three-dimensional shape drawing method


A communication system includes an echo canceller and double-talk detector. The echo canceller includes an adaptive finite impulse response filter that generates an adaptive filter weight vector. The double talk detector computes a squared norm of the filter weight vector and detects an increase of the squared norm in order to detect double-talk status. Upon detection of double-talk status, operation of the echo canceller is suspended.

The present invention relates generally to communication systems and, more particularly, to a double-talk detector for use with an echo canceller.
In long distance telephonic communications, the need for echo cancellation arises from impedance mismatches associated with wire line telephone subscribers and the use of two-wire connections between wire line subscribers and the central telephone offices. Two-wire connections require mixing of transmitted and received telephone signals for exchange between the central telephone office and the wire line subscriber. This mixing results in a portion of a received signal being re-transmitted as an outgoing signal from a receiving or near-end party to a transmitting or far-end party. As a result, the re-transmitted signal may represent a distracting echo in the communications.
While the echo problem described above is referred to as a network echo, another type of echo is acoustic echo. FIG. 1 illustrates a communication system 100 in which acoustic echo can occur. In system 100, a signal x(n) from the far-end party is received and reproduced at a loud speaker 102 of the near-end party. As a result, an acoustic echo signal c(n) can follow an echo path H(n) and be picked up by a near-end microphone 104. As a result, the far-end party may hear the acoustic echo signal c(n) while speaking.
For minimization or elimination of echo of either type occurring in a telecommunications system, there is typically provided an echo canceller. Thus, system 100 includes an automatic echo canceller (AEC) 106 which is coupled to receive the far-end signal x(n) and an echo compensated version e(n) of the near-end signal when a control switch SW1 is closed. Canceller 106 generates an output signal y(n) that is subtracted from a near-end signal d(n) from microphone 104 to yield compensated signal e(n). Thus, when there is no near-end local source signal s(n) being generated, e.g., the near-end party is not speaking, the value of e(n) should be small.
In general, echo canceller 106 comprises an adaptive finite impulse response filter (AFIR). The filter generates a mathematical model of the echo characteristics based on the far-end signal and the echo compensated signal e(n). Generation of the mathematical model includes generation of an adaptive filter weight vector designated W(n). During echo cancellation operation, the AFIR adjusts the weight components of vector W(n) to minimize or eliminate echo. Thus, operation of the filter is typically an iterative process. A more complete explanation of the use of AFIRs for echo cancellation is disclosed in xe2x80x9cAdaptive Filter Theoryxe2x80x9d by S. Haykin, Prentice-Hall International, Inc., 3rd. Edition, ISBN:0133979857, which is incorporated in its entirety herein by reference.
Operation of an adaptive filter for echo cancellation is adversely affected by the occurrence of double-talk. Double-talk occurs when both the near-end party and the far-end party are speaking and where the magnitude of the speech signals of the near-end party is much greater than that of the echo, thereby interfering with the operations of the adaptive filter. As a result, the adaptive filter is unable to accurately respond to the near-end party""s speaking and the value of the filter weight vector W(n) is not adjusted for effective echo cancellation.
In response to this phenomenon due to double-talk, there have been developed various techniques for detecting the occurrence of double-talk, so that the operation of the AFIR can be temporarily suspended when double-talk occurs. To this end, system 100 includes a double-talk detector (DTD) 108 connected to control switch SW1 to isolate canceller 106 from signal e(n) when double-talk occurs.
One type of conventional detector is a power-type double-talk detector such as disclosed in U.S. Pat. No. 4,360,712. Such a detector calculates a power ratio between the near-end and far-end signals and compares the ratio with a threshold value. Double-talk is deemed to occur when the ratio exceeds the threshold value. Another type is a correlation-type double-talk detector such as disclosed in xe2x80x9cA New Double-Talk Detection Algorithm Based on the Orthogonality Theoremxe2x80x9d by Ye et al., IEEE Transactions on Communications, Vol. 39, No. 11, Nov. 1991. Such a detector calculates an average cross-correlation (ACC) of an error signal and the far-end signal, and compares the ACC with a threshold value. Double-talk is deemed to occur if the ACC exceeds the threshold. A further type of detector is a linear prediction coefficient (LPC) detector such as disclosed in U.S. Pat. No. 5,483,594. In such a detector, the forward signal is submitted to a finite-impulse-response linear-prediction filter in order to determine a first residual signal of minimal energy. The return signal is submitted to a finite-impulse-response filter the coefficients of which are the same as those of the linear-prediction filter of the forward signal in order to determine a second residual signal. The ratio of the energies contained in the first and second residual signals is calculated. Then it is determined whether the return signal contains components other than the echo components from the forward signal by comparing the calculated ratio to a detection threshold, to thereby determine whether double talk is occurring.
A drawback of the above-described conventional double-talk detectors is that they utilize algorithms that are computationally intensive and/or are sensitive to noise.
Accordingly, the present invention is directed to a double-talk detector that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the method and apparatus particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described, the invention is directed to a double-talk detector for use with an echo canceller having an adaptive filter, the adaptive filter coupled to receive a far-end signal and an error signal which is a difference between a near-end signal and an output signal of the adaptive filter, the adaptive filter adapting a weight vector used for generating the filter output signal to minimize the error signal. The double-talk detector comprises: means for detecting an increase of a squared norm of the adaptive filter weight vector; and means for determining whether the increase of the squared norm exceeds a predetermined value corresponding to a double-talk condition.
Also in accordance with the present invention there is provided an echo canceller for canceling from a near-end signal an echo received in a far-end signal, comprising: an adaptive filter coupled to receive the far-end signal and an error signal which is a difference between the near-end signal and an output signal of the adaptive filter, the adaptive filter including means for adapting a weight vector, used for generating the filter output signal, to minimize the error signal; and a double-talk detector coupled to receive the weight vector and detect an increase of a squared norm of the weight vector, the detector including means for determining whether the increase exceeds a predetermined value corresponding to a double-talk condition.
Further in accordance with the present invention there is provided a method for detecting double-talk in an echo canceller for canceling from a near-end signal an echo received in a far-end signal, comprising: receiving the far-end signal and an error signal which is a difference between the near-end signal and an adaptive filter output signal; adapting an adaptive filter weight vector to generate the output signal with a value to minimize the error signal; detecting an increase of a squared norm of the weight vector; and determining that a double-talk condition exists when the rate of increase exceeds a predetermined value.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention, and together with the description serve to explain the principles of the invention.

Industrial Technology Research Institute


A hollow, strap-like eyeglass retainer (20) which provides audio electronic connections to interact with radio or other audio signal producing equipment (46) and audio speakers.

Related devices to the instant invention are stereo earphones, headsets, radio glasses and eyeglass retainers as cited in certain United States and foreign patents.
Headsets, headphones, eyeglass retention and radio glasses are generally shown in one or more of the following United States and foreign patents: U.S. Pat. No. 4,882,769 (Gallimore), the disclosure of which relates to an AM/FM radio supported and mounted within a pair of sunglasses; U.S. Pat. No. 4,856,086 (McCullough), which describes an electronic device mounted in the temple of a pair of eyeglasses; U.S. Pat. No. 4,965,913 (Sugarman), which illustrates a strap for retaining glasses about the neck ready for convenient use; U.S. Pat. No. 4,820,036 (Seet) describes a headband for retention of glasses; U.S. Pat. No. 4,864,646 (Nesibit et al.) has a speaker and radio in a wide, flat strap; U.S. Pat. No. 4,764,962 (Ekman et al.), describes a typical "WALKMAN" carrier; Japanese Patent No. 59-223096 (Seiko Denshi Kogyo) and West German Patent No. DE3509658-A1 (Eberhardt) show typical headsets.
None of these references cited appear to arrange an AM/FM stereo radio into an eyeglass retainer form having a comfortable flexible cloth strap or buoyant rubber tube and/or the like, concealing an antenna, electrical wires and/or air hoses wherein the retainer is adapted to be connected to a set of expandable eyeglass. An earpiece supported by a flexible arm attached directly or intermediately to the retainer forms a housing for a micro AM/FM stereo with speakers.

381
FSC 181
FSC 351
FSC 24
FSC 2
FSC 455


An information processing method and a first electronic device are provided. The method includes: triggering a communication unit of a first electronic device to perform a detection; acquiring a second state parameter of a second electronic device, if the communication unit detects that a device distance between the first electronic device and the second electronic device meets a preset condition; and controlling a display unit of the electronic device to display a second icon in a first interface with a first manner. The second icon is for representing the second electronic device, and the first manner is determined based on the second state parameter.

With the development of the information processing technologies, information may be acquired by human in a variety of ways. For example, the information may be downloaded from the internet, or may be received with the radio. Furthermore, an electronic device may be employed to acquire information transmitted by other electronic devices.
For example, a first electronic device transmits information to a second electronic device. The first electronic device firstly needs to identify that the second electronic device is an electronic device with a demand for acquiring the information. According to a conventional solution, in the case that a device distance between the second electronic device and the first electronic device meets a preset condition, e.g., in the case that the device distance between the second electronic device and the first electronic device is within 10 m, the first electronic device searches for a device name of the second electronic device, and then determines, based on the device name, that the second electronic device is an electronic device with a demand for acquiring information.
However, the conventional solution at least has the following technical problems.
In the case that the first electronic device finds multiple second electronic devices having a same device name or having ambiguous device names, for example, device model numbers are taken as the device names, the first electronic device may fail to distinguish, among the multiple second electronic devices, the electronic device with the demand for acquiring information from electronic devices without the demand for acquiring information. Therefore, the first electronic device may have a difficulty to determine, among the multiple second electronic devices, the second electronic device to which the information should be transmitted, or the first electronic device may transmit the information to multiple second electronic devices, thereby causing unnecessary information transmission.
Accordingly, the conventional technical problem is that, when the first electronic device transmits information to the second electronic device, the first electronic device can not identify the second electronic device as the electronic device with the demand for acquiring information.

Information processing method and first electronic device for detecting second electronic device


A power tool is provided including a brushless direct-current (BLDC) electric motor having a stator and a rotor. The power tool includes power switches including high-side switches and low-side switches disposed on a direct-current (DC) bus line between a power supply and the electric motor, and a controller configured to electronically brake the motor by simultaneously closing the high-side switches or the low-side switches to electrically short the stator windings. In an embodiment, the controller is configured to monitor a voltage of the DC bus line, and if the voltage of the DC bus line is lower than a voltage threshold, execute electronic braking by toggling between closing the high-side switches and closing the low-side switches over braking cycles, and if the voltage of the DC bus line is greater than the voltage threshold, execute braking by closing only the high-side switches or the low-side switches over the braking cycles.

Cordless power tools provide many advantages to traditional corded power tools. In particular, cordless tools provide unmatched convenience and portability. An operator can use a cordless power tool anywhere and anytime, regardless of the availability of a power supply. In addition, cordless power tools provide increased safety and reliability because there is no cumbersome cord to maneuver around while working on the job, and no risk of accidently cutting a cord in a hazardous work area.
However, conventional cordless power tools still have their disadvantages. Typically, cordless power tools provide far less power as compared to their corded counterparts. Today, operators desire power tools that provide the same benefits of convenience and portability, while also providing similar performance as corded power tools.
Brushless DC (BLDC) motors have been used in recent years in various cordless power tools. BLDC motors offer many size and power output advantages over universal and permanent magnet DC motors. BLDC motors are electronically-controller via a programmable controller, and thus do not suffer from many mechanical failures associated with universal motor.
Since BLDC motors are electronically commutated, the controller can also brake the motor electronically. Braking the motor brings it to a quick stop, rather than allow it to coast down. Conventional motor brakes involved complex mechanical components, which are no longer needed when braking the motor electronically. Electronic braking provides many advantages over conventional brakes. However, the way the motor voltage affects the rest of the power tool circuit should be accounted for when executing electronic braking. What is needed is a system and mechanism that allows for effective execution of electronic braking without jeopardizing the performance of the rest of the power tool.

Electronic braking of brushless DC motor in a power tool


A ballistic barrier incorporates a flexible ballistic blanket having a threat side and a protected side, opposing top and bottom edges, and opposing side edges. A plurality of spaced-apart elongated stiffening elements extend longitudinally between opposing top and bottom edges of the ballistic blanket. An elongated structural brace extends laterally between opposing side edges of the ballistic blanket, and is arranged to support the ballistic blanket in a desired lateral configuration.

The present disclosure relates broadly and generally to the ballistics industry, and more particularly to a ballistic barrier. The invention may be designed in any given size, shape, and configuration, and for any required threat level (from Level 1 to Level 8) without departing from basic design features and principles disclosed in this specification. The invention may be used alone or in combination with other ballistic elements including, for example, bullet resisting acrylics and bomb blast resistant polymers, such as polycarbonate.


The present invention comprises an articulator for registering an upper dental cast to a lower dental cast. The articulator includes an upper member subassembly with left and right sides and a lower member subassembly with left and right sides each composed of plastic material. The articulator further has at least one hinge member engaging one of the members allowing one of said members to pivot relative to the other member and a coupling means flexibly connecting the upper member subassembly to the lower member subassembly. The articulator further includes disconnectable connection means joined to one of the members for disengaging the upper member subassembly and the lower member subassembly whereby the upper and the lower member subassemblies may be separated, and a clipping means for removably securing the upper member subassembly to the upper dental cast and the lower member subassembly to the lower dental cast such that said upper and lower dental casts can be properly and flexibly aligned.

1. Field of the Invention
This invention relates generally to a dental apparatus for assisting dentists and technicians working with cast dental models for constructing prosthetic denture elements outside the patient's mouth. More particularly, this invention relates to an improved articulator which provides for flexible adjustability, convenient use and mass-production.
2. Description of the Prior Art
It is important that articulators used for supporting impressions of human jaws with artificial teeth including a lower jaw model and an upper jaw model, be capable of simulating the full range of occlusal and masticatory registrations among the patient population. The lower jaw model and the upper jaw model are supported by the articulator to be positioned in a contiguous relationship to provide centric, lateral and protrusive movement relative to each other and to simulate a patient's bite. While there are a wide variety of shapes, sizes and arrangements of human jaws and teeth, configurations and occlusion patterns have a broad range among different patients. Nevertheless, the process of making a jaw impression and the fabrication of partial dentures, fixed bridges and crowns by using jaw models in a dental laboratory requires that precise registration and desired occlusal alignment be maintained. Therefore, in order to satisfy this full range registration requirement, it often requires use of articulators which are complex, difficult to operate and expensive.
An articulator which has a wide range of registration and is simple to use, has been disclosed by Callne in U.S. Pat. No. 5,076,786, entitled "Cast Dental Articulator System and Method", issued on Dec. 31, 1991 wherein an articulator comprising two U-shaped wire frames is disclosed. These two frames are joined by hinges and springs. The frames may be snapped onto plastic clips cemented to the dental casts whereby the dental casts may be easily removed and reattached to the articulator in a highly repeatable manner. A slip-joint also provides the flexibility for left and right height adjustment to fit a wide range of dental cast models. The slip-joint further allows the upper wire frame to be completely separated from the lower wire frame.
While the articulator as disclosed in the aforementioned Callne Patent has a wide range of registration and is simple to use, it is desirable to provide an articulator structure with greater adjustment flexibility which is also renderable to being manufactured of light weight materials.


Release of a resin mold from a photopolymeric mold is enhanced by using an unsaturated fatty acid ester release agent in the photopolymeric composition. In addition to providing quick release of the resin mold, the incorporation of the unsaturated fatty acid ester improves the flexibility of the photopolymeric mold without sacrificing tensile strength or hardness. The resin mold is used to fabricate rubber plates for ink printing.

1. The Field of the Invention
This invention relates to photopolymerizable compositions from which printing plates, or molds for making printing plates, are formed. This invention is particularly directed to printing plate molds having improved release characteristics.
2. The State of the Art
Photopolymerizable or photocurable polymers are used in the manufacture of printing plates. Such compositions typically contain monomers or "prepolymers" in which polymerization is initiated by light (actinic radiation). Polymerization can be initiated by using high energy radiation, such as in the ultraviolet frequencies, and the efficiency of the radiation is typically enhanced by the addition of a photoinitiator to the composition. The monomers or prepolymers include unsaturated bonds which participate in free radical polymerization upon exposure to actinic radiation, and thereby change the macroscopic structure of the composition from a fluid form to a solid form.
These photocurable resins can be used directly in the manufacture of printing plates. Typically, a liquid photocurable composition is cast onto a substrate, covered with a protective film, and selectively exposed to radiation in a desired pattern for reproduction; exposure is typically performed through a mask or transparency having opaque portions. Those portions of the composition exposed to actinic radiation polymerize and become insoluble to a solvent later used to wash away the unexposed portions. The entire plate is then exposed to radiation to assure that the composition over the entire surface of the plate is cured, which results in a printing plate devoid of tackiness. The result is a hardened photopolymer for use as a printing plate for imprinting the exposed pattern. The final plate is mounted onto a press; the relief portions of the printing plate pick up ink and so the plate can be used to make inked impressions.
U.S. Pat. No. 2,760,863 to Plambeck is related to such compositions. By the method in the Plambeck patent, printing plates are produced directly by exposing to actinic light, through an image bearing transparency, a layer of an essentially transparent photopolymerizable composition; this composition includes an addition polymerization initiator, and cross-links upon exposure to actinic radiation. The layer of photopolymerizable composition (suitably supported) is exposed until substantial polymerization of the composition occurs in the exposed areas; substantially no polymerization should occur in the unexposed, shaded areas. The unpolymerized material in the latter areas is then removed using a suitable solvent. The result is a raised relief image corresponding to the transparent areas in the transparency.
Compositions of the type described by Plambeck generally are prepared from polymeric compositions which require organic solvents for removal of the unexposed portions. Due to the toxicity, high volatility, and generally low flash point of low cost organic solvents, their use often gave rise to hazardous conditions. As a result, further research was directed towards the development of photopolymerizable compositions soluble in water or aqueous alkali. For example, U.S. Pat. Nos. 3,794,494 and 3,960,572, the disclosures of which are both incorporated herein by reference, describe water or aqueous alkali dispersible compositions which are suitable when polymerized for use as rigid or elastic flexographic printing plates. These patents describe the use of unsaturated polyesters or polyester-polyether urethane-linked block polymers containing acrylate or methacrylate end groups as the photopolymerizable composition. U.S. Pat. No. 4,198,238, the disclosure of which is incorporated herein by reference, describes aqueous-based photocurable compositions for fabricating soft printing plates suitable for printing with ultraviolet-curable inks; these compositions generally include a mixture of a polyether or polyester linked by a carbamoyl (urethane) to a terminal olefinic group in combination with a low molecular weight unsatured polyester and an ethylenically unsaturated monomer. Thus, a number of aqueous-based photocurable compositions are presently used; these systems allow the unexposed composition to be washed away with soap and water (i.e., water and suitable surfactants and/or detergents). The production of printing plates from a mixture of a photopolymerizable urethane prepolymer and an ethylenically unsaturated compound (such as vinylpyridine or acrylic acid) are described in U.S. Pat. No. 4,358,354, the disclosure of which is incorporated herein by reference. Further descriptions of photopolymer compositions for printing and other applications are contained in the following U.S. Pat. Nos. 3,989,609; 4,218,294; 4,218,299; 4,442,302; 4,837,126, and 4,849,321; the disclosures of which are all incorporated herein by reference.
The aforementioned U.S. Pat. No. 4,218,294 discloses photocurable coatings which, when used as a release coating or oxygen barrier, include the addition of a waxy material such as paraffin wax, ester wax (e.g., stearyl acetate, a saturated C.sub.18 fatty acid ester), fluorocarbon wax, or a silicon-containing material in amounts of 0.1% to 1.0% by weight.
As previously mentioned, these composition may also be useful in the fabrication of molds from which several printing plates can be cast. In this application, the photocurable composition is used to make a positive mold, which is then used to make a negative mold, and the negative mold is used to make a rubber positive printing relief. Generally, these photopolymerizable compositions are the same as those wherein the photopolymer is used directly for printing. Printing plates are relatively softer to facilitate transfer of printing ink to the substrate; in contrast, molds are subject to heat and pressure, and so rigidity is required to prevent distortion of the mold image. Accordingly, the use of relatively harder prepolymers and monomers with more rigid (sterically hindered) side chains, and of a relatively greater amount of cross-linking agents, are some means for tailoring the composition to mold making.
U.S. Pat. No. 4,749,750 discloses lubricating or release compounds for poly(vinyl chloride) (PVC) plastics which comprise a polyester with a comblike structure; the polyester is obtained by condensing at least one C.sub.12-14 hydroxy carboxylic acid with at least one monocarboxylic acid and/or glycerol chain terminator. These polyesters are described as providing superior lubrication properties in comparison with montan esters, i.e., esters from long-chain carboxylic acids with dihydric or polyhydric alcohols (e.g., glycol or glycerol). The release compounds are present in an amount of 0.3 to 3, preferably 0.5 to 1.0, parts by weight for each 100 parts of the PVC polymer. Montan wax is a hard, brittle mineral wax usually derived from lignites and is used especially for polishes, carbon paper, and insulating compositions.

Process for printing using a photopolymeric mold made from photopolymerizable compositions with improved release properties


A silver halide photographic material comprises a silver halide emulsion layer provided on a support. The silver halide emulsion layer contains a heterocyclic selenium or tellurium compound represented by the formula (Ia), (Ib), (Ic) or (Id): ##STR1## in which each of Ch.sup.1, Ch.sup.3, Ch.sup.6 and Ch.sup.12 is Se or Te; and each of Ch.sup.2, Ch.sup.4, Ch.sup.5, Ch.sup.7, Ch.sup.8, Ch.sup.9, Ch.sup.10, Ch.sup.11, Ch.sup.13, Ch.sup.14 and Ch.sup.15 is O, S, Se or Te. Other selenium or tellurium compounds are also disclosed.

A photographic material comprises a silver halide emulsion provided on a support. The silver halide emulsion is usually chemically sensitized with various chemical sensitizers to obtain a desired sensitivity or gradation. Examples of the chemical sensitizers include a chalcogen (sulfur, selenium or tellurium) sensitizer, a noble metal (such as gold) sensitizer, a reduction sensitizer and a combination thereof.
An improvement of the silver halide photographic material has increasingly been demanded for several years. The recent photographic material requires very high sensitivity. Further, the photographic image requires an improvement of the graininess and the sharpness. A rapid image forming process such as a quick development process is also necessary. The sensitization and the sensitizers have been improved to meet these requirements.
Sulfur sensitization has most frequently been used in the silver halide photography. Numerous sulfur sensitizers have been known and used in silver halide photographic materials.
On the other hand, selenium or tellurium sensitization is more effective than the sulfur sensitization. Accordingly, selenium or tellurium sensitizers have been proposed in place of the sulfur sensitizers. However, the proposed sensitizers have a tendency that fogs easily occur in the image and gradation of the image is softened. Therefore, the sensitizers should be further improved to be used in place of the conventional sulfur sensitizers.
U.S. Pat. No. 3,297,447 discloses selenourea derivatives (e.g., dimethylselenourea) as improved selenium sensitizers. However, the improvement is still insufficient, and a rather dense fog is observed in the image (as is shown in Tables in Examples of the present specification).
The above-mentioned chalcogen sensitization is usually used in combination with a gold sensitization. The combinations of the sensitizations remarkably improve the sensitivity of the photographic material. However, the combinations also increase the degree of fog in the image. The fog in gold-selenium or gold-tellurium sensitization is more remarkable than that in gold-sulfur sensitization. Accordingly, the fog caused by a selenium or tellurium sensitizer should be reduced particularly in the case that the selenium or tellurium sensitizer is used in combination with a gold sensitizer.
By the way, chalcogen compounds have also been used as silver halide solvents, silver halide ripening agents, antifogging agents or stabilizers. For example, U.S. Pat. Nos. 4,111,697 (Pollet et al), 4,782,013 (Herz et al) and Japanese Patent Provisional Publication No. 3(1991)-91735 disclose selenium or tellurium compounds. The disclosed compounds are effective as silver halide solvents, silver halide ripening agents, antifogging agents or stabilizers, but are not available as chalcogen sensitizers.

Silver halide photographic material containing selenium or tellurium compound