A direct resin veneer (2) for creating a veneer on a tooth surface comprising a thin planar expanse of an uncured restorative material, or direct resin veneer (4). The veneer (4) has a generally tooth configuration that is generously sized to permit adequate coverage for any tooth. Adhered to at least one side of the restorative material is a flexible pliant non-sticky planar sheath (6). The sheath (6) material has a curved gingival arch contour (10) for gum line alignment and various tab-like protrusions that permit placement upon a tooth. An inferior peeling tab (12) allows for sheath to be separated from the resin veneer (4) subsequent to tooth surface placement. And the lateral grasping tabs (16) permit delivery to a tooth's surface.

1. Field of Invention
This document applies to the field of Dentistry and in particular to veneer the outer or facial surface of a tooth with a preformed uncured composite resin of uniform thickness for the purpose of attaining the desired esthetic result more expediently.
2. Prior Art
Many times in Dentistry, a patient will present with teeth that he or she will consider esthetically unpleasing. Typically these are the visible or front teeth that may display multiple restored areas, discolorations, uneven edges, congenital malformations, etc.
Dentists possess many restorative modalities to confront these various situations. They range from simply bleaching the teeth to fully covering the tooth with a crown. More often than not, the teeth are otherwise structurally sound and functional as to not need aggressive restoring. For these instances, dentists will elect to alter the facial or external surface of the tooth resulting in a cosmetic improvement to the tooth with minimal invasion or removal of sound tooth structure. Presently, minimally invasive cosmetic alterations of the tooth can be accomplished by placing a cover or veneer on the surface of the tooth which allows for altering both its shade and shape. This can be accomplished either with a directly applied veneer, or an indirectly applied veneer. Briefly, an indirect veneer is one that is fashioned extra-orally, typically in a dental laboratory. After tooth preparation, an impression is taken of the tooth and sent to the laboratory. The patient then returns for a subsequent visit to have the fabricated veneer inserted. The other method, direct placement, and the one that concerns this patent, is fabricated directly on the patient's prepared tooth, while the patient remains in the dental chair. The dentist, in his armamentarium, possesses an array of composite resin restorative materials of various shades with which to apply to the tooth for the purpose of shade and or anatomical alteration of the prepared tooth. Typically, the dentist will dispense the appropriate shade and quantity of resin, and apply the dispensed mass directly to the prepared tooth and proceed to tamp down the mass to a uniform thickness while simultaneously manipulating the mass to conform to the outline of the prepared tooth. The process of arriving at a uniform deposition of resin material involves the repeated application and reduction or resin before uniformity is achieved. This translates into a tedious process, consuming chair time, which can lead patient stress and a reduction of the dentist's office efficiency. DIRECT PRESS ON VENEER, by virtue of providing the clinician with a pre-shaped tooth covering consisting of uncured resin of proper shade, enables him or her in a singular motion to cover or veneer the tooth and thereby eliminate the tedium associated with the previously described conventional method of application.
Thusly, the veneer may upon application, be polymerized trimmed, polished and permanently bonded to the prepared tooth. Typically veneer resins are less viscous so that they may be manipulated more readily on the tooth surface. This lower viscosity is a result of lower filler content relative to the binding matrix. Consequently, the surface hardness is lessened and the ability to maintain a luster is diminished. The Direct Press On Veneer technique allows for a resin with higher filler content, and concomitant increased hardness and maintenance of surface luster. As an alternative, the Direct Press On Veneer may be utilized as a means for temporization when the intent of the dentist is to restore the tooth with a direct type veneer. In such case, the Direct Press On Veneer would be temporarily affixed to the prepared tooth for the purpose of intentional removal at the time of insertion of the finished direct veneer. Simultaneous application of resin to two or more teeth may provide a broader esthetic result and or serve to splint or connect teeth for the purpose of reinforcing a periodontally compromised tooth.
While there does exist a myriad of composite resin dental restorative materials, they exist primarily encapsulated in bulk form, whether it be in compule or syringe. The Direct Press On Veneer exists as a preformed entity of specific dimensions whose application is unique from the traditional manner of veneering a tooth. As such, there is no past or current modality which employs preformed, shaped, tooth facial coverings to be applied in the un-polymerized state.
Accordingly several advantages of the present provisional patent application of Brian D. Viscomi for DIRECT PRESS ON VENEER are:                1. Allows dentist to select veneer of desired shade        2. Veneer's uniform thinness eliminates bulky appearance        3. Uniform thickness allows for consistent appearance with multiple placements        4. Preformed shape is quickly adapted to tooth thereby expediting the procedure        5. Preformed veneers can serve as temporization for subsequent indirect veneer placement        6. Can be finished and polished either intra or extra-orally        7. Tint and opaque mediums may be applied to either tooth substrate or preformed veneer        8. Broad application of resin permits simultaneous multiple restorations        9. Engaging adjacent teeth may aid in splinting of a periodontally involved tooth        10. Accommodates a higher filled resin to enhance durability.


Multi-pass parallel merging in a database includes identifying characteristics of non-final pages during database query operations. A phase of page consolidation is triggered based on the identified characteristics and a final page is stored.

Computers are powerful tools for storing and providing access to vast amounts of information. Computer databases are a common mechanism for storing information on computer systems while providing easy access to users. A typical database is an organized collection of related information stored as "records" having "fields" of information. As an example, a business may have a database of employees. The database of employees may have a record for each employee where each record includes fields designating specific properties or information about any employee, such as, but not limited to the employee's name, contact information, and salary.
Between the actual physical database (i.e., the data actually stored on a storage device) and the users of the system, a database management system or DBMS is typically provided as a software cushion or layer. In essence, the DBMS shields the database user from knowing or even caring about the underlying hardware-level details. Typically, all requests from users for access to the data are processed by the DBMS. For example, information may be added or removed from data files, information retrieved from or updated in such files, all without user knowledge of the underlying system implementation. In this manner, the DBMS provides users with a conceptual view of the database that is removed from the hardware level. The general construction and operation of database management systems is well known in the art.
Increasingly, businesses run mission-critical systems which store information on database management systems. Each day more and more users base their business operations on mission-critical systems which store information on server-based database systems, such as SAP® Sybase® IQ (available from SAP AG of Delaware). SAP Sybase IQ is an analytics engine based on columnar database architecture, which stores data in columns. IQ is powered with a parallel bulk load engine. For non-partitioned tables, the load engine generates "final pages", which are defined as normal data pages containing contiguous row IDs. Row ID (RID) contiguousness is crucial for fast data retrieval, because a column data projection algorithm used by the system is optimized when a page only includes consecutive row IDs, as opposed to row IDs with gaps. When operating with hash or hash-range partitioned tables, non-contiguousness of row IDs presents query inefficiencies. For a hash or hash-range partitioned tables, a typical page generated by the parallel bulk load engine includes regions of row IDs from different partitions. These pages are referred to as "intermediate pages" (IPs). Intermediate pages result in degraded query performance, because the column data projection algorithm has to constantly jump between different pages.
The features and advantages of embodiments of the invention will become more apparent from the detailed description set forth below when taken in conjunction with the drawings. In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. Generally, the drawing in which an element first appears is indicated by the leftmost digit(s) in the corresponding reference number.

Multi-pass, parallel merge for partitioned intermediate pages


A paper feeding device which includes a pickup roller assembly picking up a sheet of paper and transferring the paper, a stopper controlling the paper so that a front end of the paper is located on a lower portion of the pickup roller, a sensing unit sensing whether the paper is loaded or not on the paper feeding board, and a probe unit that is rotated with the stopper and turns on/off the sensor unit. Therefore, the probe unit for turning the sensor unit on/off is operated with the stopper to reduce the number of components, thus reducing the cost and stabling the quality of product.

1. Field of the Invention
The present invention relates to an image forming apparatus, and more particularly, to a paper feeding device including a paper sensing device which decides whether a sheet of paper is loaded.
2. Description of the Related Art
In general, an image forming apparatus such as a laser printer, a scanner, and a multi functional peripheral device is an apparatus for forming a visual image by providing a sheet of paper with ink or toner according to data to be printed.
The image forming apparatus includes a plurality of sensors on a transfer passage of the paper for sensing whether the paper is transferred smoothly along the transfer passage or not.
Especially, one of the sensors is a paper sensing device, which can sense the paper is loaded or not. The paper sensing device senses the paper loading to perform a pre-operation of a paper pickup operation for forming the visual image on the paper.
On the other hand, devices having different functions are combined to be a device having multi-functions at present, thus a multi-functional peripheral device combining the devices having different functions such as the printer, scanner, copying machine, and facsimile is developed.
The combination of the devices accompanies miniaturization of components, and the components also have multi-functions.
Accordingly, in a pickup roller assembly, which picks a sheet of paper up and transfers the paper into the main body, a pickup roller and a sensing device are disposed independently, thus complicating the device and increasing cost due to a lot of components.


The same number of grooves 20 through 27 are provided in end surfaces 19a and 19b of a roller 19. The grooves 20 through 27 have communicating portions 20a through 27a which communicate with an inner peripheral side of the roller 19 and sealed portions 20b, 20c, 20d, 20e, 20f through 27b, 27c, 27d, 27e and 27f each of whose cross-sectional area decreases. Accordingly, the cross-sectional area is decreased in direction in which a lubricating oil flows, and a plurality of oil pressures can thus be obtained. This results in a fixed clearance of roller 19.

In recent years, there has been an increasing demand for a reduction in the size of a compressor for use in the refrigerating cycle. This is achieved by employing a rotary type compressor in place of a reciprocating type compressor.
However, the rotary compressor has a drawback in that the motion of a roller is unstable because the direction of the rotation thereof on its own axis changes during a single rotation thereof, deteriorating the volumeric efficiency thereof.
A conventional rotary compressor will be described below in detail with reference to FIGS. 1 through 4.
Reference numeral 1 denotes a sealed casing and 2 denotes an electric motor portion which is coupled, through a shaft 3, to a mechanical portion body 9 including a cylinder 4, a roller 5, a vane 6, a main bearing 7 and a sub bearing 8. The shaft 3 has a main shaft 3a, a sub shaft 3b and a crank 3c which is eccentric from the axis of the main and sub shafts 3a and 3b by E. The shaft 3 has a hole 3e at the center thereof, and the crank 3c has an oil supplying hole 3f and an oil supplying groove 3g. Reference numeral 10 denotes a spring provided on the rear surface of the vane, and 11a and 11b respectively denote a suction chamber and a compression chamber formed within the cylinder 4 by the roller 5, the vane 6 and the main and sub bearings 7 and 8. The inner peripheral sides of end surfaces 5a and 5b of the roller 5 which respectively face the main and sub bearings 7 and 8 are tapered to form tapered portions 5c and 5d whose cross-sectional area decreases toward the outer peripheral side thereof. Reference numeral 12 denotes an oil supplying mechanism coupled to the shaft 3. Reference numeral 13 denotes a suction pipe which communicates with the suction chamber 11a via a suction passage 14 formed in the sub bearing 8 and the cylinder 4. 15 denotes a discharge hole which communicates with the interior of the sealed casing via a discharge valve 16. 17 denotes a discharge pipe which is opened into the sealed casing 1. 18 denotes a lubricating oil.
In FIG. 4, the arrow of the solid line indicates the direction of the motion of the roller 5 which is obtained at a certain time during the operation of the compressor, and the arrow of the broken line indicates the direction in which the lubricating oil 18 flows over the end surfaces 5a and 5b of the roller as a consequence of the operation of the roller 5. Reference numeral 5e denotes a portion of the tapered portion 5c or 5d of the roller 5 whose cross-sectional area gradually decreases in the direction indicated by the arrow of the broken line, and 5f denotes a portion whose cross-sectional area gradually increases in the same direction.
The compression mechanism of the rotary compressor will now be described. A refrigerant gas supplied from a cooling system (not shown) passes through the suction pipe 13 and the suction hole 14, and then reaches the suction chamber 11a of the cylinder 4. Thereafter, the refrigerant gas is gradually compressed by the rotary motion of the shaft 3 which is generated by the rotation of the electric motor portion 2 in the compression chamber 11b defined by the roller 5 rotatably supported by the crank 3c of the shaft 3 and the vane 6. The compressed refrigerant gas is discharged into the interior of the sealed casing 1 through the discharge hole 15 and the discharge valve 16, and then discharged into the cooling system through the discharge pipe 17.
The high-pressure lubricating oil 18 with the refrigerant contained therein and contained in the sealed casing 1 is supplied to the hole 3e of the shaft 3 by means of the oil supplying mechanism 12. Thereafter, the lubricating oil 18 is supplied to the sliding portion of the main and sub bearings 7 and 8 and to the crank 3c and the inner peripheral side of the roller 5 from the oil supplying hole 3f and the oil supplying groove 3g to lubricate the roller end surfaces 5a and 5b. Subsequently, the lubricating oil 18 passes through the suction chamber 11a and the compression chamber 11b, is discharged into the sealed casing 1 from the discharge hole 15, and then stays at the bottom of the sealed casing 1.
As the shaft 3 is rotated, the roller 5 rotates while turning round about the crank 3c in either of two directions. Consequently, the locus of a certain point on the roller 5 is spiral, and the direction of the movement of the roller 5 changes about 360.degree. while the shaft 3 is rotated. Assuming that the direction of the spiral motion of the roller 5 is that indicated by the arrow in FIG. 4, since the tapered portions 5c and 5d are provided on the end surfaces 5a and 5b of the roller 5 and the cross-section of the portion 5e gradually decreases toward the outer diameter side of the roller, only the lubricating oil 18 which flows into the vicinity of the portion 5e in the tapered portion 5c or 5e generates an oil pressure due to the wedge effect. Consequently, the oil pressure near the tapered portion 5c balances the oil pressure near the tapered portion 5d, and the roller 5 is thus retained such that a clearance .delta.a between the roller 5 and the main bearing 7 is equal to a clearance .delta.b between the roller 5 and the sub bearing 8. The amount of lubricating oil with the refrigerant contained therein which flows into the suction chamber 11a and the compression chamber 11b from the crank 3c through the roller end surfaces 5a and 5b is proportional to the cube of the clearance. Therefore, where .delta.a+.delta.b=constant, the amount of lubricating oil which flows in is at a minimum when .delta.a=.delta.b. Thus, the provision of the tapered portions 5c and 5d assures a compressor exhibiting an excellent volumeric efficiency and hence a high efficiency.
Such a compressor is disclosed in, for example, Japanese Utility Model Publication No. 61-20317.
However, in a compressor which has the above-described structure and in which the thickness of the roller, indicated by (outer diameter - inner diameter)/2, is small and the ratio of the high pressure to the low pressure during operation (compression ratio) is high, as in the case of a small compressor for refrigeration having a small cubic capacity, even if the clearance between the end surface of the roller and the main bearing is made equal to the clearance between the end surface of the roller and the sub bearing by the provision of the tapered portions, the clearance of the tapered portion provided over the entire periphery practically increases by a value corresponding to the amount of taper, and the sealed distance of the flat surface where no tapered portion is provided decreases over the entire periphery, increasing the amount of lubricating oil with the refrigerant contained therein which flows into the suction chamber and the compression chamber. Thus, the provision of the tapered portion does not ensure reduction in the leakage loss and improvement in the volumeric efficiency.
The above-described structure utilizes the wedge effect of the lubricating oil which enters the tapered portion. This wedge effect is generated by the component of the roller rotation in the spiral motion thereof caused by the rotation of the shaft and not generated by the component of the roller rotation about the crank, because the cross-sectional area of the tapered portion remains the same in the circumferential direction, and is thus low. Furthermore, the oil pressure is generated by the wedge effect only at the single portion on the end surface of the roller, and no oil pressure is generated at most of the portion of the end surface. Furthermore, since the tapered portion has a shape which continues in the circumferential direction, the pressure generated by the wedge effect may escape in the circumferential direction, reducing the pressure generated by the wedge effect. Therefore, the stability of the roller achieved by the wedge effect is not sufficient, and the improvement in the volumeric efficiency is low.


A disclosed power level measuring device includes a power calculator for calculating power values based on correlation values between a received signal and known signals, for each of sampling times within a predetermined period; a time divider for switching connection of input signals, responding to time slots allocated to each of plural cells; an accumulator connected to the time divider, for accumulating the power values; a detector for detecting at least one sampling time whose accumulated value is greater than a threshold; a memory connected to the time divider, for storing the power values; and an outputting unit for outputting a measured power level, based on the stored power value corresponding to the detected sampling time.

1. Field of the Invention
The present invention generally relates to a power level measuring device and a mobile station in a mobile communications system having a plurality of cells.
2. Description of the Related Art
In a mobile communications system including a plurality of cells, a mobile station generally detects the cell transmitting the pilot channel having the largest reception power, when initializing or during an intermittent receiving situation. When performing soft handover, such a mobile station detects the cell transmitting the pilot channel having the second largest reception power.
In a W-CDMA communications system, three stage cell searches are performed, using frame timing, scrambling code groups detected by P-SCH, S-SCH, and scrambling code utilized for spreading CPICH (Common Pilot Channel).
The mobile station performs the cell search, and specifies scrambling codes and despreading timings.
The cell search is required for carrying out RAKE synthesis of signals received via multipath. For each path, CPICH is used to specify despreading timings (path timings).
The path timings are likely to move forward and backward depending on the communications environment. Therefore, the path search should be performed regularly even after path timing detection.
Based on the path timings obtained through path searching, the mobile station reports power levels from ambient cells to the network when required.
FIG. 1 is a functional block diagram of a prior art power level measuring device that can be mounted on a communication apparatus such as a mobile station of a mobile communications system.
The power level measuring device comprises a path searching unit 110 and a demodulation unit 130. The path searching unit 110 comprises a matched filter 112, a power calculator 114, a power accumulator 116, a peak detector 118, and is also called a "searcher".
The path searching unit 110 has a cell searching function (three stage cell searching function) mentioned above. Path searching is explained below.
The demodulating unit 130 comprises a sliding correlator 132, a power calculator/synchronous detector 134, a RAKE synthesizer 135 and a level converter 136. Plural sliding correlators 132 performing despreading are provided, and they are used in despreading received signals with respect to each multipath or each channel.
Timing at which each sliding correlator 132 despreads is in accordance with path timing reported by the path searching unit 110.
Path searching and level measuring processes performed in the path searching unit 110 are explained below.
The matched filter 112 calculates correlation values cpich_symbol [m] [i] between a received signal "x" and known codes "c" for each sampling time within a predetermined range by the following Equation 1.
                                          cpich_symbol                                      [              m              ]                                                      [            i            ]                          =                              ∑                          k              =              1                        nscode                                                                                x                                            [                                  t                  +                                      (                                          m                      -                      320                                        )                                    +                                      (                                          i                      ×                      1024                                        )                                    +                                      4                    ×                    k                                                  ]                                      ×                          code                                            [                k                ]                                                                        Equation                                                  1
wherein "m" is a parameter defining a sampling time, and m=0, 1, . . . , 638, 639. The symbol "i" is a parameter defining a data symbol number, and i=0, 1, 2, . . . . Summation is done in the range of k=1, 2, . . . , nscode. The nscode is the number of chips included in one symbol of a CPICH signal, for example 256 chips. The symbol "t" means a path timing, which is determined by path searching. Within ±320 samples from this path timing being center, 640 correlation values as a total are calculated per one symbol. In this prior art example, one chip is represented by four samples (four times over sampling). The relationship between "t" and "m" is illustrated in FIG. 2A. Code[k] means a spreading code, and may be represented by a product of a channelization code CC[k] and a scrambling code SC[k].
The power calculator 114 calculates a sum of squares of in-phase and quadrature coefficients of the correlation values to obtain a power value (the received signal x is modulated with a quadrature modulation method). Such a power value is calculated for each of the 640 correlation values obtained per symbol.
The power accumulator 116 accumulates the power values obtained over 640 samples, at each sampling time. Accordingly there appear plural paths near to path timing "t".
The peak detector 118 selects four path timings t0, t1, t2 and t3 corresponding to the four largest paths near to "t", based on the accumulation results in the power accumulator 116 (cf. FIG. 2(B)). Using each of the path timings, the heading frame of the following received signal is maintained properly for each multipath, and power measuring is performed in the demodulation unit 130.
The sliding correlator 132 uses the four path timings t0, t1, t2 and t3 reported by the peak detector 118, and calculates a correlation value cpich_symbol [n][i] between the following received signal and known signals by the Equation 2.
                                          cpich_symbol                                      [              n              ]                                                      [            i            ]                          =                              ∑                          k              =              1                        nscode                                                                                x                                            [                                                      t                    n                                    +                                      (                                          i                      ×                      1024                                        )                                    +                                      4                    ×                    k                                                  ]                                      ×                          code                                            [                k                ]                                                                        Equation                                                  2                            wherein "n" is a parameter defining four path timings, n=0, 1, 2, 3. Other symbols are the same as the above. In this manner, four correlations that are despread received signals are output for each symbol.
The power calculator/synchronous detector 134 averages the despread signals and outputs the averaged signals to the RAKE synthesizer 135. The power calculator/synchronous detector 134 can perform power calculation when measuring power level, and can perform synchronous detection when demodulating data. When demodulating data, data after RAKE synthesizing are output to a demodulating part (not shown), not to the level converter 136.
When a base station is under a transmission diversity condition, averaging is performed after pilot-canceling a received signal from one antenna, and RAKE synthesis is performed similarly.
The RAKE synthesizer 135 performs RAKE synthesis on each path (four paths), and outputs RAKE synthesized signals to the level converter 136.
The level converter 136, based on the RAKE synthesized signals, calculates a signal-to-noise power ratio Ec/No per chip. By multiplying this value with received signal strength RSSI, adequately converted power level RSCP is calculated.
The received signal strength can be determined by a radio unit (not shown) provided before the power measuring unit, based on a control signal of an automatic gain controller.
Thus calculated level measured value is transmitted to a network controlling device (RNC) via a radio base station, and utilized for handover control or other processing.
FIG. 3 is a timing chart with respect to level measuring and path searching.
As shown in the upper portion of FIG. 3, a radio signal received at a mobile station comprises a frame (10 ms) including a plurality (15) of time slots.
The level measuring is performed for plural cells (#0-#3) during one frame, and cells to be level-measured are switched at every 1.5 slots in the shown example.
As shown in the upper portion of FIG. 3, cell #0 is level-measured at the head of one frame. Next, cell #1, then cell #2, cell #3, and again cell #0. In this manner, despreading codes set in the sliding correlator 132 are switched so that each cell is level-measured twice during one frame.
The reason why 1.5 slots are allocated to the level-measuring time for each cell is to consider switching time for despreading codes. One slot is consumed for measuring power and switching despreading codes is done during 0.5 slots as overhead.
The middle portion of FIG. 3 shows path searching periods.
As shown in FIG. 3, a path search for one cell is performed during one frame, and cells to be path-searched are switched at every frame.
That is, despreading codes given to the matched filter 112 are switched at every frame.
In this example, the path search results for each cell are reflected (revised) immediately after measurement.
That is, as for cell #0, the path search results obtained during the first frame are applied to the second frame-the sixth frame. The level measurement during the period is carried out so that the sliding correlator 132 performs despreading according to the path timing detected in the first frame.
Next cell search for cell #0 is performed in the sixth frame. The level measurement on and after the seventh frame is performed based on path timings detected during the sixth frame.
The detected path timings can be given to a despreading processing unit for demodulating data.
The lower portion of FIG. 3 shows level measuring time by width of bars. Only Cell #0 is shown, but level measurement is also done for cell #1, cell #2 and cell #3, of course.
Correlation shown by a solid line typically represents that the reception level varies due to fading. It can be seen that the level measuring period is dispersed and therefore the influence of fading is well suppressed by averaging by power calculator/synchronous detector 134.
Another prior art communications system is described, for example, in Japanese Laid-Open Publication No. 11-317694.
The mobile station uses both the correlator in the path searching unit and the correlator in the demodulation unit, and therefore consumption of power in the correlators becomes twice as much.
It is one object of the present invention to reduce power consumption required for power level measuring.
Especially when a sliding correlator is used for correlation detecting, a plurality of multiplying circuits are provided for correlation calculation resulting in large circuit size. In this case, it is highly desirable to reduce power consumption.
A mobile station goes into a waiting mode in order to reduce power consumption, except while it is used for talking. A network may give an instruction to a mobile station anytime and the mobile station has to measure power level even while it is in the waiting mode. Then the mobile station starts the demodulation unit 130 and consumes power for purposes other than talking. This is disadvantageous especially for small mobile phones having limited battery capacity.
The received signal used by the peak detector 118 for determining path timings t0, t1, t2 and t3 is different from the received signal used by the sliding correlator 132 for despreading for level measurement.
That is, in FIG. 3, the path detected by path searching for cell #0 during the first frame is applied to the following second and sixth slots. The received signal used for path searching and the received signal used for level measuring do not have the same position.
Since the path search is done within any one frame in the path revision period, it is difficult to deal with environmental variation in the path revision period.

Power level measuring device and a mobile station


A bubble generator to bring out performance of a Doppler ultrasonic flowmeter to the maximum extent is provided.

In Japanese Patent Application Laid-Open No. 2000-97742, there is disclosed a Doppler ultrasonic flowmeter that permits precise, highly accurate and contactless measurement on a time-dependant basis even in the case of a flow in an unsteady state.
Patent document 1: Japanese Patent Application Laid-Open No. 2000-97742.
The Doppler ultrasonic flowmeter disclosed here has a structure as described below. Specifically, it has an ultrasonic transmitting means emitting an ultrasonic pulse of a predetermined frequency from an ultrasonic transducer into the fluid to be measured along a measurement line, a fluid velocity distribution measuring means receiving, out of the ultrasonic pulses emitted into the fluid to be measured, an ultrasonic echo reflected from a measurement region to thereby measure a flow velocity distribution of the fluid to be measured in the measurement region and a flow rate computing means performing an integration on the basis of the flow velocity distribution of the fluid to be measured. The flow rate computing means measures the flow rate based on the flow velocity distribution of the fluid to be measured in the measurement region.
This Doppler ultrasonic flowmeter measures the flow velocity distribution of the fluid to be measured which flows in a pipe, and exhibits an excellent performance in response to the flow rate in a transiting duration in which temporal fluctuations are seen. Further, even at a part in which the flow of the fluid is insufficient or at a place in which the flow is three-dimensional, for example, at a place of the pipe just after it is bent such as of an elbow pipe or a U-shaped inversion pipe, it is possible to measure the flow rate of the fluid to be measured efficiently, highly accurately and instantly. In comparison with conventional ultrasonic flowmeters offered therebefore, as a feature, the Doppler ultrasonic flowmeter can perform the measurement experimental values, empirical values and so forth, being highly evaluated.
Meanwhile, when the above-described Doppler ultrasonic flowmeter measures the flow velocity distribution (flow rate) by taking advantage of a Doppler effect of ultrasonic pulses, reflective bodies are required in the fluid to cause Doppler shifts. When the fluid has no reflective body therein, the measurement is impossible. Still, when the refractive bodies are not mixed into the fluid uniformly, the flow velocity distribution lacks, so that the accurate flow velocity distribution can not be obtained.
When the fluid to be measured is the fluid (for example, water), as a refractive body, a gas having largely different acoustic impedance therefrom such as air or helium is preferable. However, the injection of the gas was performed using a nozzle inserted into the fluid pipe, a sufficient refractive echo intensity could not be obtained unless the gas grows to a size appropriate for the reflection of the ultrasonic waves used for the measurement in the fluid to be measured. Besides, it is impossible to obtain the appropriate flow velocity distribution unless the gas is dispersed uniformly in the emitting direction of the ultrasonic pulses.
An object of the present invention is to provide a measurement technology enabling to measure the flow rate more accurately even under an environment where the contained refractive bodies are not sufficient, by way of uniformly injecting such bubbles into the fluid to be measured that have the size suitable for the predetermined frequency of the ultrasonic pulses.
Therefore, in one embodiment, a bubble generator is used to bring out the performance of a Doppler ultrasonic flowmeter to the maximum extent.
Further, in another embodiment a Doppler ultrasonic flowmeter is provided with a bubble generator to bring out the performance to the maximum extent.

Bubble generator for use in doppler ultrasonic flowmeter and doppler ultrasonic flowmeter

Abstract: The bubble generator is provided with a bubble generation member generating bubbles suitable for a predetermined frequency of an ultrasonic pulse emitted into a fluid to be measured and feeding the bubbles into the fluid pipe, and a uniform dispersion member dispersing the bubbles fed uniformly in the pipe, the bubble generator is installed on an upstream side of the fluid pipe with respect to an ultrasonic transducer. The bubble generation member has a Venturi tube, and the uniform dispersion member has a negative pressure generating device, in which the fluid to be measured drawn out by the uniform dispersion member from inside the fluid pipe is returned into the fluid pipe together with the bubbles fed into the fluid pipe via the Venturi tube.

The Tokyo Electric Power Company, Incorporated


An embodiment of the present invention is an interconnect technique. A nanostructure bump is formed on a die. The nanostructure bump has a template defining nano-sized openings and metallic nano-wires extending from the nano-sized openings. The die is attached to a substrate via the nanostructure bump.

1. Field of the Invention
Embodiments of the invention relate to the field of nanotechnology, and more specifically, to nanotechnology in packaging.
2. Description of Related Art
Current first level interconnect technology involves metal, typically copper (Cu), bump formation on the silicon die and solder formation on the substrate side, using either stencil printing or electroplating. During chip attachment process, the solder reflows to form an electrical interconnect between the die and the substrate.
The existing interconnect technology has several problems or limitations. First, metals are susceptible to electro-migration, especially at high current densities. As the pitch and size of bumps become smaller for higher density interconnects, the current density carried by the metal bumps is also increasing. This leads to worsened electro-migration, posing serious reliability risks. Second, high density interconnects require decreased input/output (I/O) pitch and therefore bump size. Existing bump pitch for processor die is approximately 180 μm. It is extremely difficult to achieve nanometer-scale interconnect (e.g., in the order of 30 μm or less) using existing materials and processes partly because of the increased resistance and the electro-migration problem.


A pump incorporates a housing with a pump chamber and an internal bore communicating with the pump chamber, and a power driven impeller shaft supported in the housing by at least one bearing in the internal bore. The impeller shaft has an impeller in the pump chamber. A seal mechanism is in the internal bore between the bearing and the pump chamber providing a seal between the impeller shaft and the wall surface of the internal bore. The internal bore has a stepped configuration with small and large diameter portions and a vertical wall defined therebetween. The large diameter portion defines an intermediate chamber between the bearing and the pump chamber and that chamber connects with the pump chamber. The intermediate chamber contains liquid with air being trapped in the remaining portion of the intermediate chamber. The bearing and the seal mechanism are located in the small diameter portion. A partition wall member in the intermediate chamber divides the chamber into a first compartment adjacent the pump chamber and a second compartment adjacent the seal mechanism. The first and second compartments are connected at the upper and radially outer peripheral portion of the intermediate chamber. A device provided on the impeller shaft forces the liquid in the second compartment when the impeller shaft rotates, so as to displace into the first compartment, while the air concentrates in the second compartment around the impeller shaft, thereby excluding liquid from the sealing mechanism.

Conventionally, a water pump for use in an engine cooling system includes a power driven impeller shaft having one end portion connected with a power source such as an output member of an internal combustion engine with the other end being provided with an impeller for drawing water from a source of water such as a water tank and forcing the water to an outlet of the pump. The shaft is mounted on a pump housing for rotation about the axis of the shaft by means of a bearing located at the end portion of the shaft adjacent to the driving power source. The impeller is rotated in the pump chamber together with the impeller shaft to force the water in the pump chamber to the pump outlet.
In order to prevent water in the pump chamber from leaking under the pump pressure prevailing in the pump chamber through the impeller shaft to the bearing, the shaft is provided with a mechanical seal that is mounted on the shaft for slidable engagement with a bore surface of the pump housing. It has been recognized however that a mechanical seal may sometimes produce a squeaking noise in operation because of slipping movements of the seal. Efforts have hithertofore been made for solving the problem. Examples of seals which may substitute for conventional mechanical seals are those having lip seals or seal devices using a magnetic fluid as disclosed for example by the Japanese Laid-Open Utility Model Publication No. Hei 1-99997 (published on Jul. 5, 1989), Japanese Utility Model Publication No. Hei 6-29517 (published on Aug. 10, 1994) and Japanese Patent Publication No. Hei 4-72110 (published on Nov. 17, 1992).
It should however be noted that these sealing structures are not satisfactory since the sealing structures are always subjected to water pressure. The sealing members may show unsatisfactory durability under prolonged contact with water. Further, the sealing members may fail under high water pressure which may be produced in operation. As the results, the sealing structures as proposed by the aforementioned Japanese patent or utility model applications do not show satisfactory reliability.

Liquid pump for preventing contact between the sealing structure and pressurized liquid


Remote communication devices (i.e., radio frequency identification (RFID) tag) and systems for communicating between one or more RFID tags and a reader using a frequency modulation method to encode binary data are disclosed herein. For example, a remote communication device includes an antenna operable to receive and backscatter a carrier signal, wherein the backscattered carrier signal further comprises a secondary signal within an identification bandwidth. The remote communication device also includes a signal processing circuit coupled to the antenna, the signal processing circuit comprising at least one encoding circuit operable to encode binary data into the backscattered carrier signal by periodically modulating the frequency of the secondary signal from one encoding frequency to another one of 2n+1 encoding frequencies within the identification bandwidth, wherein n is an integer greater than or equal to 1.

Remote communication using wireless equipment may rely on radio frequency (RF) technology. One application of RF technology is in locating, identifying, and tracking objects, such as animals, inventory, and vehicles. Other applications of RF technology may include communication of data collected from remote sensors.
RF identification (RFID) tag systems have been developed to facilitate monitoring of remote objects and communication of data collected from remote sensors. As shown in FIG. 1, a basic RF tag system 10 may include three components, an antenna 12, a transceiver with decoder 14, and a transponder (commonly called an RFID tag) 16. In operation, the antenna 12 may emit electromagnetic radio signals generated by the transceiver 14 to activate the RFID tag 16. When the RFID tag 16 is activated, data can be read from or written to the RFID tag 16.
In some applications, the antenna 12 may be a component of the transceiver and decoder 14 to become an interrogator (or reader) 18. The reader 18 may activate or "wake up" the RFID tag 16 by radiating energy to the tag in an on/off pattern encoded in some time varying manner. When an RFID tag 16 passes through the electromagnetic radio waves 20, the RFID tag 16 detects the signal 20 and is activated. An example of one manner commonly used to activate an RFID tag is biphase encoding. When the reader 18 is done talking to the RFID tag 16, the reader 18 may then go to a continuous broadcast of energy that the RFID tag 16 uses to communicate information to the reader via backscatter methodologies. Data encoded in the RFID tag 16 may be communicated to the reader 18 by a data signal 22 through an antenna 23. The RFID tag 16 may modulate its antenna and put a subcarrier on the reader's backscattered carrier signal that could later be stripped off and demodulated. The subcarrier may use a time varying amplitude shifting modulation technique such as biphase modulation to encode the data into the subcarrier signal.
RFID tag communication systems may include systems where the RFID tags return data at a specific frequency associated with each RFID tag. For example, a reader may transmit a signal at one frequency, and each RFID tag can modulate the amplitude of its signal at a frequency separate from the frequency of any other RFID tag in the system. Such systems can allow the reader to simultaneously differentiate information received from multiple RFID tags. Further, the RFID tags may be configured to allow a tag to communicate at one of several frequencies and to adaptively avoid interference with other tags that may be communicating on an identical frequency. While an RFID tag may adaptively change the frequency at which it is communicating, the means for communicating information still relies on a method of modulating the amplitude of a signal in some time varying fashion to encode data in the signal.
Several disadvantages may be associated with encoding a signal from an RFID tag by modulating the amplitude of a signal in some time varying fashion. For a reader to decode a time varying amplitude modulated system, it may be required to accurately identify the amplitude change times. To accurately identify an amplitude change time, a minimum signal to noise threshold may need to be maintained to clearly detect the edge of an amplitude change. A reader may be required to sample the returned signal at some rate higher than twice the data bandwidth such as 10 times the data bandwidth. The reader may obtain little processing gain from averaging the signal sampled since signal averaging can smear the edges of amplitude changes and can raise the sample requirements further.
Thus, it would therefore be desirable to have a system and method for communicating between one or more RF tags and a reader such that the data transfer rate may be increased, and the error rate may decrease. It would be desirable to increase the data transfer rate and decrease the error rate without significantly raising the cost of a system. Further, it would be desirable to have a system and method for communicating between one or more RF tags and reader such that multiple RF tags can communicate with the reader simultaneously.

Remote communication device and system for communication


An integrated inspection system adapted to inspect a substrate. A first inspection station performs a first inspection of the substrate at a first resolution, and identifies defect candidate sites. A controller determines position information associated with each of the identified defect candidate sites. A second inspection station performs a second inspection of the defect candidate sites at a second resolution, where the second resolution is higher than the first resolution. A substrate stage moves the substrate between the first inspection station and the second inspection station, and indexes the substrate under both the first inspection station and the second inspection station.

The integrated circuit industry relies on the continual and repeated inspection of integrated circuits as they are produced to ensure that processes are operating properly and that the integrated circuits themselves are properly formed. Automated inspection is normally the preferred method of inspection of integrated circuits. However, as integrated circuits evolve, they are becoming smaller and more complicated. Thus, there has been continual pressure to detect and classify a growing number of defects and other conditions that may be present on the substrate, but which are increasingly more difficult to see. In addition, fabrication units are producing more and more integrated circuits so as to reduce the overhead costs associated with production, and to satisfy the demands of the modern world. Such demands have resulted in a desire to reduce the time associated with integrated circuit inspection
Current inspection methods in integrated circuit manufacturing typically use two completely separate inspection tools. The first inspection tool typically inspects all of the substrate surface to identify candidate defect sites. These first inspection tools typically use optical techniques and are limited in resolution by the wavelengths of the light that they use. These first inspection tools identify many candidate defect sites, whose defect size is typically below the resolution of the optical first inspection tool used. Thus, a second higher resolution, but much slower, inspection tool is then typically used to inspect and provide high resolution images of each of the candidate defect sites. These high resolution images are then typically used to classify the defects that may or may not be found at the candidate defect sites.
The second inspection tool is typically an electron microscope. Thus, in a typical process, the integrated circuit substrate is first inspected using the first inspection tool, and then the substrate is removed from the first inspection tool and placed in the second inspection tool to further investigate the candidate defect sites, and to determine which defects identified by the first tool are those that may impact device yield. The coordinate system of the first tool must be re-acquired by the second tool, costing additional time. This may be followed by a re-inspection with the first tool with modified inspection parameters to improve its capture of these more important defects. Repeatedly transferring the substrate from the first inspection tool to the second inspection tool is time consuming, and therefore costly.
Typically, only a subset of the candidate defect sites have actual defects that negatively affect process yield. Thus, the slower second inspection tool is often bogged down by inspecting candidate defect sites that have no bearing on device yield.
What is needed, therefore, is a system for reducing the amount of handling and time needed to identify and classify those defects that impact device yield on a substrate.


An infrared radiation detector using a reflector comprising a mirrored conic section or faceted reflector to increase the field of view of a sensor. The reflector is mounted in the normal field of view of the sensor, and is truncated so as prevent the reflector from blocking radiation directly in front of the detector. The detector is mounted either on a wall with a nearly 180 degree field of view, or on a post with a nearly 360 degree horizontal field of view and a nearly 180 degree vertical field of view.

The present invention relates to infrared radiation detectors. Infrared detectors are often used to sense the presence of people in connection with home burglar alarm systems or automated room lighting systems. To prevent an intruder from escaping detection by a burglar alarm system, a detector must be able to detect radiation coming from anywhere within a wide field of view.
Unfortunately, with planar sensors, sensitivity drops as the angle between the radiation beam and a line normal to the plane increases. This is because the cross section of the sensor available for absorbing radiation decreases as the angle increases. One solution is to use a detector with several sensors fixed at different angles relative to each other in such a configuration where the sum of the sensors' narrow fields of view cover a larger solid angle. However, this complexity increases the cost of the detector, and applications which use infrared detectors are often cost-sensitive applications.

Wide-angle passive infrared radiation detector


A method and device providing a HA junction varactor which may be fabricated with a reduced variation in C-V tuning curve from one varactor to the next. The process produces a varactor with an active region formed substantially by doping an Si substrate with various dopants at various energy levels. Accordingly, unit-to-unit device variation is reduced because etching, growing, and deposition processes to make the active portion of the varactor are reduced or eliminated. The resulting HA junction has a more uniform thickness, and a more uniform doping profile.

1. Field of the Invention
The invention generally relates to varactors and, more particularly relates to hyper-abrupt (HA) junction varactors and a method of fabrication of HA junction varactors in CMOS, rf-CMOS, BiCMOS or analog technologies.
2. Background Description
Varactors form a class of tunable semiconductor capacitors typically derived from pn-junctions, where the pn-junction is operated in a reverse bias state. The capacitance of the varactor may be varied by adjusting the reverse bias voltage, and thus varactors are characterized by a C-V tuning curve. Varactors are especially useful in oscillator circuits, especially voltage-controlled oscillators, where the varactor tunability is used to tune the oscillation frequency of the circuit. Thus, varactors find use in cellular phones, televisions and radios, computers, active filters, and wherever a first signal is synchronized to second signal.
Varactor functioning is most easily understood in the terms of a basic capacitor. In general, a capacitor consists of two conductive plates separated by a dielectric. Opposite charges collect on the capacitor plates when a voltage potential is applied across the plates. The capacitance of the capacitor, and its ability to hold a certain amount of charge at a certain voltage, depends on the distance between the two plates, among other parameters. The larger the distance between the two plates, the less the capacitance and the less charge the capacitor can hold at a given voltage potential.
A pn-junction may function as a capacitor in the reverse bias mode because the reversed voltage potential causes charge carriers to move away from the pn-junction. The facing edges of the p and n regions collect the charge and act as the conductive plates, i.e. the anode and cathode. As the charge carriers move away from the pn-junction, a depletion region near the junction is formed which is the equivalent of a dielectric in a standard capacitor. As the voltage potential is increased, the charge carriers move farther away from the pn-junction, which is equivalent to increasing the distance between the two conductive plates of a standard capacitor. Accordingly, the capacitance of a varactor is, in part, voltage dependent and may be tuned over a particular range. The capacitance of a varactor is also dependent on other parameters such as junction area and the doping densities in the junction.
The doped region of a varactor is typically formed in semiconductor film deposited on the varactor cathode. Different doping profiles within the film may be used to achieve different capacitance-voltage tuning relationships (C-V tuning curves). The first varactors were constrained to linear doping profiles because of fabrication limitations. Such varactors have a C-V tuning curve where capacitance is proportional to the inverse cube root of the tuning voltage. As fabrication methods improved, it became possible to closely control doping profiles, and varactors with uniform doping profiles became available. The uniform doped varactors have C-V tuning curves where capacitance is proportional to the inverse square root of the bias voltage.
For some varactor applications, a linear C-V tuning curve is preferred, and thus HA junction varactors were developed. HA junction varactors have a doping profile which changes in a controlled non-linear way with density of the dopants increasing towards the junction and abruptly dropping to zero at the junction. With a suitable profile, the varactor″s capacitance can be linearly dependant on bias voltage over at least a portion of the varactor″s tuning curve.
HA junction varactors may be made with various methods including ion implantation and molecular beam epitaxial growth. As noted above, one of the parameters which affects the capacitance, and C-V tuning curve, of a varactor is the doping profile within the LTE (low temperature epitaxial) layer. Thus, as doping density varies, so does the C-V tuning curve of the varactor. The doping profile may be affected by, among other things, the thickness of the LTE layer. Consequently, the C-V tuning curve of varactors in a particular manufacturing batch may vary significantly from one unit to the next based on variations in the LTE layer thickness. In some examples, the C-V tuning curve has as much as a 50% variation in capacitance in the middle of the curve.
The cause of variations of the LTE layer thickness may be due to variation in initial LTE layer formation as well as changes in the LTE layer thickness caused by subsequent manufacturing steps. Such device variation due to manufacturing variation may be difficult for the design engineer to accommodate and lead to complicated circuit designs and extra steps in circuit fabrication.
Though the C-V tunability of varactors may offer the circuit designer increased freedom in designing certain circuits, known varactors have C-V tuning curves which may vary substantially from one unit to the next. Such variations are due to variations in the fabrication process, such as etching, layer formation, and doping the multiple layers of semiconductor forming the active region (cathode, collector, junction, and anode) of the varactor. In fact, varactor C-V tuning curves may vary by as much 50% from the nominal specification called for by the designer. Accordingly, circuit designs must make more complicated circuits to accommodate C-V tuning curve variation. But, such complicated fabrication processes, and circuit complexity increase the cost of varactor implementation.
Referring to FIG. 1, a related art varactor is shown. The varactor 10 has a Si (silicon) substrate 12 with an N+ subcollector 14 formed therein. The N+ subcollector 14 is positioned in a lower portion of the Si (silicon) substrate 12 and may be formed by ion implanting methods well known to those skilled in the art. For example, arsenic ions can be implanted into the Si substrate 12 to form the subcollector 14 with a dosage of about 1.4×1016 atoms/cm2 at about 40 KeV energy levels. It should be noted that there are typically diffusion areas adjacent to the N+ subcollector 14, such as, for example, at each end of the N+ subcollector 14 where some of the dopants would diffuse into the surrounding Si substrate 12. The N+ subcollector 14 functions as the cathode of the varactor 10. After forming the N+ subcollector 14 region in the substrate 12, an optional epitaxial Si layer may be formed atop the surface of the substrate 12 utilizing conventional epitaxial growing processes.
Above a portion of the N+ subcollector 14 is a collector 16. The collector 16 is formed by doping the Si substrate 12 with first conductivity type ions of either N-type or P-type. For example, the collector 16 may be formed by implanting with phosphorus ions at about 6×1012 atoms/cm2 at energy levels of about 700 KeV. Above the N+ subcollector 14 on either side of the collector 16 and next to a reach through implant 20 are isolation regions 18. The isolation regions 18 may be isolation oxides, and may further be shallow trench isolation oxides. In the case where the isolation regions 18 are shallow trench isolation oxides, the isolation regions 18 may be formed, for example, by conventional lithography, etching, and shallow trench fill methods well know to those skilled in the art.
At one end of the Si substrate 12 and between two of the isolation regions 18 is the reach-through implant 20. The reach-through implant 20 extends from a top surface of the varactor 10 into the Si substrate 12 and is in electrical communication with the N+ subcollector 14. The reach-through implant 20 may be formed using conventional methods well known in the art. Accordingly, the same ion dopant utilized to dope other regions of the varactor 10, such as used for doping the N+ subcollector region 14 may be used to form the reach-through implant 20. For example, the reach-through implant 20 may be formed with Sb (antimony) dopant with a 1.4×1014 atoms/cm2 density at about 200 KeV, or it maybe formed with P (phosphorus) dopant with a 4×1015 atoms/cm2 density at about 70 KeV.
On top of the reach-through implant 20 is a silicided region 32. The silicided region 32 serves to provide good ohmic contact to the underlying reach-through implant 20, and may be formed by methods well known in the art.
On top of the collector 16 is an HA junction 24. The HA junction 24 is formed in the Si substrate 12 above the collector 16 region. The HA junction 24 is formed by doping methods well known in the art. For example, the HA junction 24 may be formed using an N-type dopant, such as Sb at a density of 5×1012 atoms/cm2 and an energy of about 40 KeV.
On top of each isolation region 18 are sacrificial layers 30. The sacrificial layers 30 serve to protect the underlying Si regions during FET processing. The sacrificial layers 30 are made of, for example, a protect dielectric such as nitride. The sacrificial layers 30 are initially deposited across substantially all of the top surface of the Si substrate 12 and protects the surface during later processing. The dielectric is etched prior to LTE processing and may leave the remaining topography. The sacrificial layers 30 may be formed, for example by PCVD (plasma chemical vapor deposition).
An LTE layer 26 is deposited over the HA junction 24. The LTE layer 26 is made from P-type Si using LTE methods well known to those of ordinary skill in the art. The LTE layer 26 is later doped with P+ type ions by necessary bipolar implants or the standard PFET source/drain ion implant. Accordingly, further bipolar processing steps are required after the HA junction 24 has been formed. Such further bipolar processing may alter the thickness, as well as other parameters, of the HA junction causing variation in the final C-V tuning curve of the varactor.
On top of the LTE region 26 is a silicided layer 34. The silicided layer 34 is formed by 1-step or 2-step silicide processes using conductive metals (i.e.: titanium, cobalt, nickel, etc.) which are well-known in the art. The silicided layer 34 serves to provide good ohmic contact to the LTE layer 26.
As noted above, either bipolar processing during and subsequent to forming the related art HA junction causes unit-to-unit manufacturing variation in related art varactor tuning curves, and such variations in varactors complicates circuit designs. Accordingly, in order to simplify the design of circuits using varactors, a fabrication process which produces varactors having less manufacturing variation in the C-V tuning curve is desirable. Additionally, HA junction varactors which have less unit-to-unit manufacturing variation in the C-V tuning curve are desired.

Structure and method for hyper-abrupt junction varactors

International Business Machines Corporation


A prefabricated sprue assembly provides attachment to independently-produced investment casting molds to substantially reduce the need for pattern material. Installable connections between the prefabricated sprue assembly and the investment mold allow substantial reduction of scrap loss caused by errors in production of individual investment molds by culling defective molds before installation to the sprue assembly.

The present invention relates to a method of investment casting and in particular to an investment casting system that reduces the amount of pattern material required for the sprue for investment casting.
In investment casting for metals or other materials, a pattern may be made of a volatilizable material such as wax or plastic duplicating the desired cast part. Multiple such patterns may be attached to a sprue providing an inverted tree-like structure of the same volatilizable material having one pattern attached to the end of each branch. The patterns and the sprue are then encased in a flowable mold material, for example, a ceramic material which hardens to form a ceramic shell around the pattern and sprue.
The mold material is heated to melt and volatize the pattern and sprue leaving a hollow central channel with tubular branches leading to cavities corresponding to each pattern (also termed sprues). A casting material, for example molten metal, may then be poured down the central channel to pass to the branches into each of the cavities. When a casting material has hardened, the mold material is removed and the cast parts separated from the sprue.
The pattern material used for the sprue can be relatively expensive and sometimes heavy, thus making handling cumbersome. Because the pattern material for the sprue is ultimately burned out, the pattern material needed to produce the sprue creates additional air pollution. The flowable mold material used for making the mold cavity, selected for strength and for preserving the fidelity of the pattern, may be suboptimal for forming the sprue in terms of weight, strength and cost.


A two-stroke engine with external fuel mixture generation in a carburetor. The engine including a suction funnel having an interior disposed upstream of the carburetor. The engine further includes a tapered insert having a narrow end and a wide end disposed in an area of an inlet port of the suction funnel. The insert at least partially defines the interior of the suction funnel, and the insert tapers in a flow direction of air flow from the wide end to the narrow end. Accordingly, a diameter of the interior of the suction funnel adjacent to the narrow end of the insert is substantially larger when compared to the narrow end of the insert.

Two-stroke engines of conventional construction usually include a so-called crank-chamber scavenging, whereby the sucked-in fuel-air mixture is led first of all into the crank chamber, which receives the crankshaft and is surrounded by the crankcase. There, the fuel-air mixture is supercharged by the piston sliding downwards in the cylinder in the working stroke, and is then transferred, when the piston frees an associated transfer passage in the cylinder wall, to the combustion chamber. In the next stroke, the piston slides upwards and compresses the transferred mixture in the combustion chamber, while at the same time a fresh mixture is sucked into the crank chamber. The terms "up" and "down" refer to an upright cylinder arrangement with the cylinder head located on top.
In a two-stroke spark-ignition engine, ignition of the fuel-air mixture compressed by the piston is effected in the combustion chamber through an active ignition device in the form of a spark plug with associated voltage supply and release electronics, when the piston passes the dead center. The burnt mixture or exhaust gas is released from the combustion chamber at the end of the working stroke through an outlet passage then freed by the piston and is, as a rule, led through an exhaust manifold into the exhaust or muffler section.
Two-stroke engines can be configured for an internal mixture generation with direct injection of the liquid fuel into the combustion chamber or for an external mixture generation in a carburettor. In the carburettor, the liquid fuel is injected into the air flow, which is sucked in or pressed in through a charging device, and atomized. A crank-chamber scavenging is in most cases combined with an external mixture generation.
Usually, a gasoline-oil mixture is supplied as fuel to such two-stroke engines, the addition of oil serving for lubricating the motor. Especially in recent times, it is desired, due to corresponding financial incentives, to replace (regular) gasoline by kerosene, which is normally used as fuel for gas-turbine engines, or also by diesel fuel.
Corresponding attempts to upgrade a two-stroke spark-ignition engine for an operation with diesel or kerosene, are known, for example, from U.S. Pat. No. 5,855,192. For an improved ignition behavior, in particular in the stage of the motor start, a heating of the cylinder head with the help of a glow pencil applied there, which is independent of the spark plug, is provided there. The cylinder head is in this case subjected to a relatively high thermal stress, which generally requires the use of correspondingly high-quality and high-temperature resistant materials and of, for example, ceramic components in the cylinder. Nevertheless, on the whole, the running behavior of motors modified in this manner zierter is not convincing.

Two-stroke engine and method for operating a two-stroke engine


Annularly ribbed tube comprises one or more coaxial co-extruded inner layers and a coaxial outer layer of thermoplastic material. The tube has sharply upstanding annular or helical ribs having a width which is small in comparison to distance between annular ribs or between turns of the helix. At least one of the inner layers of extrudate fills a hollow outer shell of each rib which is formed by the outer layer. An innermost layer may be a smooth inner skin or may have a smooth inner wall and another wall which bulges into the rib cavity.

1. Field of the Invention
This invention relates to annularly ribbed tube and to a method and apparatus for its production.
2. Background of the Invention
It has become conventional to use corrugated tube, possibly double-walled corrugated tube, or annularly ribbed tube for thermoplastic, semi-rigid tubing frequently used as drainage conduit for underground use, or for carrying electrical cables. A corrugated or double-walled corrugated tube has some advantages and annular ribbed tube has other advantages. For example, corrugated tube, whether or not double-walled, tends to be of lighter construction than ribbed tube. It may be made by blow molding techniques which do not require such high extrusion pressures as do the injection molding techniques which are required for ribbed tube. On the other hand, corrugated tube is not as sturdy as ribbed tube and, when it is double-walled, special provisions must be made to allow for equalization of pressure within the closed corrugated envelopes between the tube walls so that these have no tendency to collapse. Various other considerations, possible specific to the intended use, apply to the choice of ribbed or corrugated tube.
The techniques necessary for the production of double-walled corrugated tube are quite well known in this field. For example, extrusion nozzles having coaxial extrusion orifices for extruding annual parisons to form each of the walls are known from U.S. Pat. No. 4,226,580 (Lupke) issued October 1980, 30 U.S. Pat. No. 4,305,703 (Lupke) issued December 1981, U.S. Pat. No. 4,500,284 (Lupke) issued February 1985, U.S. Pat. No. 4,510,013 (Lupke) issued April 1985, and U.S. Pat. No. 4,534,923 (Lupke) issued August 1985.
The Patents quoted above are merely exemplary of a large number of patents in this field.
Ribbed tube differs from corrugated tube by its greater rigidity which is, inter alia influenced by the longitudinal spacing of annular or helical ribs which upstand relatively sharply from an outer tube surface, at least in comparison to the smooth waves of corrugated tube. The tube wall, including the ribs, is generally relatively dense and the tube is, therefore, heavy.
The thickness of the ribs in the longitudinal direction of the tube may be small in comparison with the distance of tube between each rib. Tube between each rib may be profiled with patterning in the form of embossed or otherwise formed annular ridges or other patterns. Such patterns are not to be confused with the sharply upstanding ribs to which the invention relates. The ribs typically, although not necessarily, upstand from the surface of the tube by at least a height equal to the tube wall radial thickness. Possibly, the rib height is as much as five times or more the radial tube thickness.
As a result of the difference in structure between ribbed tube and corrugated tube, the molding techniques in forming ribbed tube are more akin to injection molding techniques than to the blow molding used for the outer skin of double walled corrugated pipe due to the extrusion pressure necessary to force plastic extrudate into the grooves to mold the ribs of the pipe. Thus, although, filled corrugations have been contemplated in the past (see German Offenlegunschrift 2,042,031), it has not been thought possible to provide ribbed pipe except as a single continuous injection extrusion.
German Offenlegunschrift 2,042,031 discloses a blow molding technique in which an outer corrugated wall is produced in a conventional manner. Downstream of this, again in a somewhat conventional manner an inner smooth wall is imposed within the corrugated wall. The German document discloses foaming the inner wall so that the extrudate expands to fill the corrugations in addition to forming the inner wall. Ribbed tube could not be produced in this manner.
Although ribbed tube as previously known is somewhat heavy and extravagant in raw material, its advantages in rigidity and strength are considerable. While considerable effort has been applied to the problem of proper penetration of the rib forming grooves by the extrudate, the problem of undue usage of plastic extrudate appears to have been regarded as insoluble.
The present invention has addressed the problem of providing a ribbed tube which is (1) lighter than previously thought possible, (2) less extravagant in materials, (3) may incorporate recycled material and (4) is of comparable quality to conventional ribbed tube.


An exhaust system for an internal combustion engine adapted to correct the problem of pollution occurring at start-up and during at least initial engine running, and characterized by an electrically heatable catalytic converter and, desirably, a separate unheated conventional catalytic converter in tandem relation. The system also provides means for providing electrical power greater than 500 watts for 2 seconds or more whereby the temperature of the catalyst is raised and maintained at least 650 F. An advantage of preferred embodiments is that there is provided a substantially improved means for augmenting conventional catalytic converter exhaust systems for modern requirements by inserting in the exhaust system an electrically heatable catalytic converter for conversion of pollutant material operative prior to, during and after start-up. Power switching means are provided for heating an electrically heatable catalytic converter and are characterized by at least one actuatable solid state switch, preferably in combination with means for actuating said switches.

The purpose of a catalytic converter is to convert pollutant materials in engine exhaust, e.g., carbon monoxide, unburned hydrocarbons, nitrogen oxides, etc. to carbon dioxide, nitrogen and water. Conventional catalytic converters utilize a ceramic honeycomb monolith having square or triangular, straight-through openings or cells; catalyst coated alumina beads; or a corrugated thin metal foil honeycomb monolith having a catalyst carried on or supported by the surface, which surface is typically wash coated with one or more metal oxides, such as alumina, ceria, lanthia, or combinations thereof, and a catalyst. The catalyst is normally a noble metal, e.g., platinum, palladium, rhodium, ruthenium, or a mixture of two or more of such metals. The catalyst catalyzes a chemical reaction whereby the pollutant is converted to a harmless by-product which then passes through the exhaust system to the atmosphere. However, this conversion is not efficient whenever the exhaust gases are relatively cold. To have high conversion efficiency, the catalyst and the surface of the converter with which the exhaust gases come in contact must be at a minimum temperature above about 200 F., e.g., 390 F. for carbon monoxide, 570 F. for volatile organic compounds (VOC), and 1000 F. for methane or natural gas. Otherwise the conversion to harmless by-products is poor and cold start pollution of the atmosphere is high. For example, about 80% of automotive pollution occurs within the first two minutes of engine operation. Once the exhaust system has come to its operating temperature, the catalytic converter is optimally effective. Hence, it is necessary for the relatively cold exhaust gases be heated or contact a hot catalyzed surface to effect satisfactory conversion at start-up.
To achieve rapid heating of the catalyst in a metallic monolith, it is necessary to draw power from a voltage source, or other source of electric energy, e.g., a battery or a capacitor device (such as the new Isuzu "electric power storage" device developed by Isuzu Motors Ltd.) until the desired temperature is reached. In an automotive vehicle, this source of energy is usually a 12 volt or a 24 volt battery, although a battery system supplying higher voltage may be used. As indicated, a battery, or a capacitor battery or, if an immobile source, a conventional AC or DC power supply may also be used as a source of energy. To accomplish this end, it has been found that one or more actuatable solid state switches connected in parallel, such as metal oxide semiconductor field effect transistors (MOSFETs) together with means for actuating such devices in unison (a gate driver) may conveniently be used. This system in vehicles enables drawing high power loads for a short period of time to achieve the desired temperature in from broadly upwards of 0.5 second, desirably above about 2 seconds, e.g., from 2 to 30 seconds, and preferably from 2 to 60 seconds of precrank preheating, and, if necessary depending upon the specific application, from 0 to 60 seconds of postcrank heating.
Reference may be had to U.S. Pat. No. 3,768,982 to Kitzner dated Oct. 30, 1973. In this patent, heat from a centrally located electric heater is transferred by conduction through a monolithic catalyst support to heat the catalyst to optimum operating temperature. Reference may also be had to U.S. Pat. No. 3,770,389 to Kitzner dated Oct. 30, 1973 which discloses a central electrically heated core within a ceramic monolith. The heating core is formed of metal sheets, one corrugated, the other flat, coated with alumina and also bearing a catalyst. The metallic core is heated electrically by virtue of its own electrical resistance. However, heating by conduction requires too long (a matter of minutes) to be practical in solving the problem of atmospheric pollution at start-up.
Reference may also be had to U.S. Pat. No. 4,711,009 to Cornelison and Retallick dated Dec. 8, 1987 for details of a process for the preparation of an accordion folded thin stainless steel foil honeycomb with an alumina coating and a catalyst on the surface thereof. This patent is incorporated herein by reference thereto.
Reference may also be had to International PCT publication number WO 89/10471 filed Nov. 2, 1989 which discloses electrically conductive honeycomb catalyst support units useful in automobiles. To obtain a suitable electrical resistance between 0.03 and 2.0 ohms, the honeycomb body is subdivided electrically, cross-sectionally and/or axially, by gaps and or electrically insulating intermediate layers or coatings so that at least one electrical current path having the desired resistance is obtained. Heating is controlled by a timed relay. Separate catalytic converters in the exhaust line, one or more electrically heatable, the other conventional, are disclosed. The minimum resistance disclosed is 0.03 ohms which when placed in a nominal 12 volt electrical system, as disclosed, may be expected to draw a current of no more than about 300 amps at the catalyst when the various voltage drops and resistances are considered. This power level has been found to be too low for effective rapid heating of electrically heatable units within from 0.5 to 60 seconds and, even if the monolith could be heated rapidly at this power level, the catalyst tends to cool rapidly to below "light off" temperature after the engine is started because of the initial cool exhaust from the engine. To counteract this cooling effect usually more than 2700 watts (less for smaller engines) are required after engine start-up. It should be noted that on some vehicles, this cooling to a lower temperature is not important if it occurs during a period of time when the engine exhaust emissions are low, in which case a lower power level (down to 500 watts) may suffice. Moreover, subdivision of the monolith into a plurality of discs or units for connection in series is not necessary.
Many millions of automotive vehicles are equipped with catalytic converters, but all are subject to cold-start emissions of what, in at least one state, has been determined to be an unacceptable level. Anticipatory elevation of the catalyst temperature to an optimum operating level before start-up is expected to be mandated for many automotive vehicles.
Moreover, the systems of the present invention will achieve an effective pollutant removing temperature, or "light off" temperature in about two seconds depending upon the power delivered from the source of electrical energy. This compares with over five minutes for converters with no auxiliary electrical heating means or those which depend upon heat conduction as the mode of heat transfer. This is an important distinction if one is obliged to wait for a catalytic converter to achieve "light off" or optimum operating temperature before starting the engine. Again, it is important to note that a major amount of pollution due to exhaust gases occurs in the first two minutes of engine operation. Some applications of the devices contemplated hereby use power supplied continuously, i.e., without a power modulating system.


A silicone rubber composition comprises: (A) an organopolysiloxane having at least two alkenyl groups in a molecule and free of an aryl group; (B) (B-1) an organosiloxane having in a molecule at least one aryl group, at least one silicon-bonded hydrogen atom, and free of an alkenyl group, or a mixture of components (B-1) and (B-2) an organosiloxane having in a molecule at least one aryl group and at least one alkenyl group; (C) an acrylic compound or a methacrylic compound; (D) an organopolysiloxane having at least two silicon-bonded hydrogen atoms in a molecule and free of an aryl group and an alkenyl group; and (E) a hydrosilylation reaction catalyst. The silicone rubber composition exhibits excellent adhesive properties with respect to diverse organic resins it comes into contact with during its cure, and at the same time possesses excellent mold-release properties with respect to metal dies used for its molding.

Silicone rubber compositions which have adhesive properties with respect to organic resins they come into contact with during their cure, and which at the same time possess mold-release properties with respect to metal dies used for their molding, are known. For example, U.S. Patent Application Publication No. 2002/0032270 discloses a silicone rubber composition comprising: a heat curable organopolysiloxane composition; reinforcing silica fines; an adhesive agent; and an organosilicon compound having a functional group reactive with the heat curable organopolysiloxane composition and a siloxane skeleton incompatible with the heat curable organopolysiloxane composition, and U.S. Patent Application Publication No. 2007/0100072 discloses a silicone rubber composition comprising: an organopolysiloxane having at least two silicon-bonded alkenyl groups in a molecule; an organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms in a molecule; an alkylene glycol ester of diacrylic acid or an alkylene glycol ester of dimethacrylic acid; and a hydrosilylation reaction catalyst.
However, because the former silicone rubber composition forms a silicone rubber with a defective appearance, it is limited in use. And, the former silicone rubber composition does not exhibit satisfactory adhesive properties with respect to diverse organic resins it comes into contact with during it cures. Furthermore, the latter silicone rubber composition does not exhibit satisfactory adhesive properties with respect to diverse organic resins it comes into contact with during it cures, while at the same time does not possess satisfactory mold-release properties with respect to metal dies used for its molding.

Silicone rubber composition and composite made therefrom