An object is to provide a latent electrostatic image bearing member that can provide high-quality images for prolonged periods, owing to photosensitive layers and crosslinked surface layers having excellent flaw and wear resistance and appropriate electric properties, image forming method, image forming apparatus and process cartridge that employ latent electrostatic image bearing member respectively. Accordingly, provided is a latent electrostatic image bearing member that comprises a support and at least a photosensitive layer and a crosslinked surface layer disposed on the support, wherein the crosslinked surface layer comprises a reactant from radical polymerizable compounds having three or more functionalities with no charge transport structure and radical polymerizable compounds having one functionality with charge transport structure, and at least two different antioxidants.

1. Field of the Invention
The present invention relates to latent electrostatic image bearing member (hereafter may be referred to as "photoconductor" or "electrophotographic photoconductor") that can provide high-quality images for prolonged periods, owing to photosensitive layers and crosslinked surface layers having excellent flaw and wear resistance and appropriate electric properties; process cartridge, image forming process and image forming apparatus that utilize latent electrostatic image bearing member respectively.
2. Description of the Related Art
Recently, organic photoconductors (OPC) are widely employed in copiers, facsimiles, laser printers, and composite apparatuses thereof owing to excellent performance and various advantages, in place of conventional inorganic photoconductors. The reasons for replacement are, for example: (1) favorable optical properties such as absorbable wavelength region and absorption rate, (2) electrical properties such as high sensitivity and stable charging ability, (3) broad selection of materials, (4) manufacturability, (5) low cost, (6) no toxic effects, etc.
On the other hand, photoconductors are more and more miniaturized as image forming apparatuses are being downsized; in addition, the trend toward speeding up and maintenance-free performance of machines are spurring the demand for ruggedization of photoconductors nowadays.
However, organic photoconductors, due to their relatively low hardness of surface layers that consist mainly of low-molecular charge transport substances and inactive polymers, tends to wear away under repeated usages in electrophotographic processes by the mechanical stress associated with developing systems or cleaning systems, etc.
To pursue high image quality, rubber hardness of cleaning blades as well as the pressure applied onto the photoconductors is being forced to increase so as to improve cleaning ability accompanied by the miniaturization of toner particles, therefore accelerating the wear on photoconductors. This kind of wear on photoconductors deteriorate sensitivity and electric properties such as charging ability etc., resulting in disordered images such as image density degradation or background smear, etc. Flaws caused by local wears often bring about streaks on images due to insufficient cleaning. Such wear and flaws typically dominate the cause of short lives of photoconductors that are being exchanged shortly.
Therefore, it is essential to reduce the amount of wear for improved durability of organic photoconductors, and it is the most significant problem in the field to be settled in a prompt manner.
Technologies to improve wear resistance of photosensitive layers, for example, (1) incorporation of curable binders into the crosslinked charge transporting layers e.g. Japanese Patent Application Laid-Open (JP-A) No. 56-48637, (2) employment of charge transport polymers e.g. JP-A No. 64-1728, (3) dispersion of inorganic fillers into crosslinked charge transporting layers e.g. JP-A No. 4-281461, and the like are proposed.
However, the technology incorporating curable binders described in (1) has insufficient compatibility with charge transport substances and residual voltage tends to increase owing to impurities such as polymerization initiators and/or unreacted residual groups, it is more likely to deteriorate image density. The technology employing charge transport polymers described in (2) can improve wear resistance in some measure; however, durability of organic photoconductors does not improve sufficiently. Moreover, electric properties of organic photoconductors are likely to become unstable because of difficulties in polymerizing and purifying charge transport polymers. Furthermore, coating liquids typically become excessively viscous for processing.
The technology in which inorganic fillers are dispersed as described in (3) may exhibit higher wear resistance compared to the conventional photoconductors in which the low-molecular charge transport substances are being dispersed into inactive polymers, however, charge traps on the surfaces of inorganic fillers tend to increase residual potential, thereby increasing the tendency for image density degradation. Also, if unevenness of inorganic fillers and binder resin of photoconductor surface is significant, defective cleaning may occur, resulting in toner filming or image deletion.
Based on these technologies (1), (2), and (3), the overall durability of organic photoconductors including electrical and mechanical durability has not achieved the satisfactory level.
Photoconductors containing cured materials of multi-functional acrylate monomers are proposed in order to improve wear and flaw resistance described in (1) e.g. JP-B No. 3262488. It is described as cured materials of multi-functional acrylate monomers are to be contained in the protective layer disposed on photosensitive layers, however, there is no specific description or examples other than the charge transport substances may be contained in the protective layers. Furthermore, when low-molecular charge transport substances are added to the crosslinked charge transporting layers, compatibility issue may arise with the cured materials. As a result, deposition and clouding of low-molecular charge transport substances may occur, in addition to the image density deterioration and reduced mechanical strength due to the increase in exposed-area potential.
More specifically, photoconductors are produced by reacting monomers with polymer binders being incorporated; therefore, three dimensional networks do not proceed sufficiently and the crosslinked joint density becomes less, failing to achieve a dramatic increase in wear resistance.
To improve wear resistance of photosensitive layers, for example, disposing charge transporting layers produced by the use of coating liquids with monomers having carbon-carbon double bonds, charge transport substances having carbon-carbon double bonds, and binder resin is proposed in JP-B No. 3194392. The binder resin is thought to improve adhesiveness between charge generating layers and curing charge transporting layers and alleviate the internal stress of film at the time of thick film curing. The binder resin can be classified broadly into two categories: binders reactive to the charge transport substances having carbon-carbon double bonds, and binders non-reactive to the charge transport substances having no double bonds. This photoconductor is remarkable in having wear resistance and proper electrical properties, however, if non-reactive resins are used as binder resin, compatibility with cured materials generated from reactions with monomers and charge transport substances may not be desirable and a phase separation within crosslinked charge transporting layers may occur, resulting in flaws or retention of external additives of toner and paper powders. As stated above, three-dimensional network does not progress appropriately and the crosslinked density becomes sparse, prohibiting the exhibition of significant wear resistance. In addition, monomers specified in Japanese Patent (JP-B) No. 3194392 have two functionalities, not sufficient for wear resistance. When a reactive resin is employed as binder resin, though the molecular mass of cured materials increases, number of intermolecular crosslinked joints is small, thus simultaneous pursuit of bonding amount and crosslinked density of the charge transport substances is difficult and electric properties and wear resistance would not be satisfactory.
Photoconductors having photosensitive layers that contain cured compounds generated from curing hole transport compounds having two or more chain polymerizable functional groups within one molecule is proposed in Japanese Patent Application Laid-Open (JP-A) No. 2000-66425. The photosensitive layer may have high degree of hardness due to increased crosslinked joint density, however, since bulky hole transport compounds have two or more chain polymerizable functional groups, distortion within cured materials may occur and internal stress becomes high and the crosslinked surface layers may yield cracks or peelings when used on long-term basis.
From these aspects and much dedicated investigations on the subject, it is found that employing crosslinked resin layer obtained from curing radical polymerizable compounds having three or more functionalities with no charge transport structure and radical polymerizable compounds having one functionality with charge transport structure as surface layer improves electric properties and wear resistance. However, this crosslinked resin layer is electrically unstable; specifically, charge deterioration has been verified after long-term use. These are assumed to be caused by the decomposition or alteration of charge transport substances or binder resin led by the eruption of NOx or ozone gases from outside or within the electrophotographic apparatus. Specifically, it is thought to be caused by the deteriorated outer surface where deterioration is most likely to be progressed, that has been retained for a long period of time because of improved wear resistance due to disposed surface protective layers.
Examples of effective countermeasures to above issues include employing photoconductors on which protective layers containing fillers, dispersants and at least two different antioxidants are disposed, as disclosed in JP-A No. 2002-207308, or employing photoconductors containing protective layers with charge transport property, syloxane resin with crosslinked structure and antioxidant, as disclosed in JP-A No. 2001-51440. However, when small amount of hindered phenol antioxidant or hindered amine antioxidant as described in above literatures are contained in the surface layers made of crosslinked resin layers produced from the curing radical polymerizable compounds having three or more functionalities with no charge transport structure and radical polymerizable compounds having one functionality with charge transport structure, the protective layers show high wear resistance compared to the conventional protective layers and the outermost surface will not get refreshed and insufficient electric stability, especially the charge property deterioration will result in long-term use. If antioxidant is contained in excessive amount, the wear resistance is deteriorated due to sensitivity degradation or crosslinking inhibition.
On the other hand, in terms of image-forming apparatuses, dehumidification of photoconductors is known as a way to refresh outermost surfaces of photoconductors, however, employing heaters will not only incur size-growth of apparatus but consumes large volume of electricity, therefore is not cost-effective. To overcome this problem, for example, the image-forming apparatus in which an exhaust path and a fan is placed between photoconductor and fixing unit so that the waste heat from the fixing unit is sent to the photoconductor via exhaust path or duct as disclosed in JP-A No. 08-179677. However, the fixing unit has a temperature as high as around 200° C. when it is under operation and the surface of photoconductor becomes hot in the image forming apparatus where the heat of fixing unit is directly transmitted to the photoconductor and the sensitivity of photoconductor is deteriorated.
Therefore, the image forming processes and associated technologies with superior endurance that can provide high-quality images for prolonged periods, having latent electrostatic image bearing members that can provide high-quality images for prolonged periods, owing to photosensitive layers and crosslinked surface layers having excellent flaw and wear resistance and appropriate electric properties, have not been obtained and in the present state of affairs, their prompt development is desirable.

Latent electrostatic image bearing member, process cartridge, image forming apparatus, and image forming process


Methods and systems for calibrating an array antenna are described. The array antenna has a plurality of antenna elements each having a signal with a phase and an amplitude forming an array antenna signal. For calibration, the phase of each element signal is sequentially switched one at a time through four orthogonal phase states. At each orthogonal phase state, the power of the array antenna signal is measured. A phase and an amplitude error for each of the element signals is determined based on the power of the array antenna signal at each of the four orthogonal phase states. The phase and amplitude of each of the element signals is then adjusted by the corresponding phase and amplitude errors.

An array antenna includes an array of antenna elements for transmission or reception of electromagnetic signals. The antenna elements are fed with one or more signals whose amplitudes and phases are determined to form a beam, i.e., an array antenna signal in a specified direction. Typically, the relative amplitudes of each element signal are fixed by attenuators set at appropriate levels to shape the beam, while phase shifters connected to the elements are adjusted for changing the phases of the signals to steer the beam.
To precisely control the beam, the actual phase response of each phase shifter must be known. However, phase response of a phase shifter is subject to unavoidable errors and variations due to manufacturing discrepancies and to various changes occurring as a function of time and temperature. Thus, calibration is required to provide phase correction for each phase shifter. The phase calibration data can be stored and used during steering operations to correct phase response errors.
The amplitudes of the signals fed to the elements are adjusted with attenuators connected to the elements. The attenuators are also subject to errors and variations. Thus, calibration is required to provide attenuator calibration data for each attenuator. The attenuator calibration data can be stored and used during steering operations to correct attenuator response errors.
Previous methods of phased array calibration have relied on scanning each element of the array through all of its phase values relative to the other elements and measuring the power of the array antenna signal at each phase value. The measured phase value corresponding to maximum power is compared to the ideal phase value. The ideal phase value is the phase value corresponding to maximum power when there are no phase errors or variations. Thus, the difference between the measured phase value corresponding to maximum power and the ideal phase value is the phase error, or phase offset, for that element.
This procedure is repeated at least once for each element of the array. After the phase offsets for each element have been determined, the phases of the element signals are changed by their respective phase offsets to effect the calibration. Consequently, the errors are, at least currently, taken into account.
A problem with scanning each element through all of its phase values is that this requires a large number of measurements. For instance, phase values fall within the range of 0.degree. to 360.degree.. Thus, if the phase settings for each element were quantized in increments of 1.degree., then three hundred and sixty phase values must be scanned. If the array has a large number of elements, for example, one hundred, then at least three thousand six hundred measurements must be made for calibration of the array, and iteration may be required to improve accuracy. Scanning each element through all of its phase values is suboptimal in a noisy environment and has the disadvantage of potentially large interruptions to service.
Accordingly, a need has developed for a quicker and more efficient method which requires fewer measurements for calibrating an array antenna.

Phase array calibration orthogonal phase sequence


A developing device for an electrophotographic apparatus and a developing roller therefor are disclosed. Polarity identical throughout a range between a magnetic conveying pole and a magnetic depositing pole on a sleeve forms a repulsive magnetic field. Therefore, even when the diameter of the sleeve is reduced for the miniaturization of the developing device, a developer can be surely released from the sleeve despite a decrease in the width of a developer releasing portion in the direction of rotation of the sleeve.

1. Field of the Invention
The present invention relates to a developing device included in a copier, facsimile apparatus, laser printer or similar electrophotographic apparatus. More particularly, the present invention is concerned with a developing device using a developer consisting of toner and magnetic carrier, and a developing roller therefor.
2. Discussion of the Background
It is a common practice with a copier or similar electrophotographic image forming apparatus to electrostatically from a latent image on a photoconductive element, or image carrier, and develop it with a developer stored in a developing device. The developing device includes a developing roller for conveying a developer consisting of toner and magnetic carrier to the photoconductive element and returning, after the deposition of the toner on the element, the carrier and excess toner to a developer storing section included in the casing of the developing device. To allow the developing roller to so operate, it has been customary to form a flux density pattern on the outer periphery of a sleeve forming a part of the developing roller. The flux density pattern is formed by a main pole for development, a plurality of conveying poles, a releasing pole, and a depositing pole.
In the electrophotographic image forming apparatuses art, there is an increasing demand for miniaturization and high-speed operation allowing a great amount of information to be rapidly dealt with in a limited space. To meet this demand, it is necessary to reduce the size of the developing device operable with the toner and carrier mixture and the size of its developing roller as far as possible.
However, the developing roller with the flux density pattern mentioned earlier has the following problem left unsolved. When the diameter of the developing roller is reduced for the miniaturization of the developing device, the actual distance on the sleeve decreases although the angle (width) may remain the same. As a result, a part of the developer on the sleeve is apt to move from the releasing pole to the depositing pole together with the sleeve before it is fully released from the sleeve, lowering image density and therefore image quality. This is particularly true when the outside diameter of the developing roller or sleeve is less than 20 mm. Further, the conventional process speed causes the sleeve to rotate at a higher speed, aggravating the above occurrence.
In light of the above, Japanese Patent Laid-Open Publication No. 9-281794, for example, teaches a developing roller on which all the magnetic poles from the conveying pole to the depositing pole are of the same polarity. In this configuration, a repulsive magnetic field is formed for exerting a magnetic force which releases the developer from the sleeve. With such a developing roller, it is possible to promote the sharp release of the developer from the roller even when the roller has a small diameter. It was experimentally found that when the poles from the conveying pole to the depositing pole were of the same polarity, the above developing roller was satisfactory as to the initial image characteristic. However, the developing characteristic and therefore development .gamma. (gamma) characteristic varied when a number of images were output, depending on the flux density pattern. As a result, a greater amount of toner was deposited on the photoconductive element, bringing about defective images due to the scattering of toner around an image and the offset to a fixing roller.

Developing device for an image forming apparatus and developing roller therefor


Search relevance failures are diagnosed automatically. Users presented with unsatisfactory search results can report their dissatisfaction through various mechanisms. Dissatisfaction reports can trigger automatic investigation into the root cause of such dissatisfaction. Based on the identified root cause, a search engine can be modified to resolve the issue creating dissatisfaction thereby improving search engine quality.

A Uniform Resource Locator (URL) is mechanism for specifying locations of resources across a network. A URL uniquely identifies both a resource and a protocol for interacting. Most often, a URL refers to the location of a website, webpage, or document on the World Wide Web (the web) accessible over the Internet. For example, "http://www.example.com," specifies retrieval of a webpage at the location specified by "www.example.com" utilizing hypertext transfer protocol ("http"). In this scenario, a web browser can accept the URL and display the resulting webpage. Where the URL is unknown, a search engine can be utilized to locate URLs that satisfy a specified query.
In order for a URL to appear in the top "N" search results for a query, a variety of processing needs to be done. At a high level, page content of the URL goes through document processing and page importance ranking. Further, the query itself is processed. Processed document content can then be matched against the processed query to determine if the page contains all query key words. If so, the document becomes a member of the document candidate set. Finally, content of the document candidate set is ranked to determine at which position in the results the URL should appear.
Document processing and page importance ranking involve crawling, indexing, classifying, and ranking. A web crawler or spider can be employed to scour the web for URLs and capture location content. Subsequently, the URL and content are indexed to enable expeditious search. Further, pages are classified and ranked to capture the authority or reliability of content. For example, a webpage is reliable if it provides links to other webpages deemed reliable.
Query processing involves refining the query to facilitate return of desired results. In one instance, the query can be filtered to remove unacceptable characters or strings (e.g., "_", "+" . . . ). Query alteration can also be applied in which spell correction, steaming, word breaking, and/or acronym expansion are performed to capture user intent better. Of course, at the same time such processing should avoid alterations that actually deviate from original user intent. Finally, more sophisticated query processing can be performed to best capture intent by distinguishing primary query words from secondary words, identifying word proximity, and/or employing natural language understanding, among other things.
Once queried a webpage may need to overcome several barriers in order to participate in dynamic ranking. For instance, where content does not include all exact keywords in a query, it must rely on either query alteration or some form of relaxed document candidate set with fuzzy matching as opposed to literal matching to enter the document candidate set.
Pages that make it into the document candidate set are dynamically ranked and need to obtain a high enough ranking to make it in the top "N" search results. Additionally, the pages may have to overcome various other restrictions such as a host-based diversity constraint. Host-based diversity constraint refers to returning only the top "M" URLs from a specific host and collapsing all others. Of course, rank can also be negatively impacted by blacklists that specify that some URLs or domains are blocked for including SPAM or malicious content, for example.

Automatic diagnosis of search relevance failures


An improved serial access memory without erroneous reading where a faster reading operation is required. The serial access memory includes a disconnecting circuit connected between a serial bus line pair and a preamplifier. A data signal read out from a memory cell is provided to the preamplifier via the serial bus line pair. The disconnecting circuit electrically disconnects the serial bus line pair from the preamplifier after a predetermined time has elapsed since the preamplifier commences amplifying operation. An equalize circuit commences equalization of a next data signal right after the operation of the disconnecting circuit. Since the equalize timing of the serial bus line pair for reading the next data is made to commence earlier, proper reading operation can be realized even if the frequency of an externally applied serial out clock signal SOC is increased.

1. Field of the Invention
The present invention generally relates to semiconductor memory devices, and more particularly to an improvement of the equalize timing of a signal transmission line for transmitting a data signal provided from a bit line. This invention has particular applicability to a serial access memory.
2. Description of the Background Art
The recent usage of semiconductor memories in various equipments have led to the need of various features. In addition to the basic features of a semiconductor memory to store an applied (or a predetermined) data and read out the stored data, the feature for access has also become necessary. Particularly, serial access, i.e. serial reading and/or serial writing of data signals, has become necessary to process video signals or image signals at a high speed.
A field memory and a video RAM, for examples, are known as random access memories (RAM) having serial access feature. In a field memory, an applied data signal is written in series into a memory cell, and the stored data signal is read out in the order that it was written. A field memory is often used as a delay circuit for video signal processing since it has a memory capacity that can store digital pixel signals of one screen of a television, for example.
A video RAM comprises a random access port and a serial access port. Through a random access port, an applied data signal is stored in an externally specified memory cell, and the stored data signal is read out from an externally specified memory cell. Through a serial access port, an applied data signal is stored in an externally specified memory cell row in series, and the stored data signal is read out in series from an externally specified memory cell row. The random access port is frequently used to carry out the image signal processing at a high speed. The serial access port is used to supply the processed signal, i.e. the stored image signal, to an image display device such as a CRT at a high speed.
A first-in-first-out (FIFO) memory, though not a RAM, is also known, for storing applied data signals in series and reading out in series the stored data signal in the order that they were stored.
It is appreciated that the above semiconductor memories are common in the point that they have a feature for reading out in series the data signal stored in a memory cell. Although the present invention is applicable to a semiconductor memory, particularly to a serial access memory having serial access feature, a field memory will be taken as an example in the following to simplify the description.
A field memory is widely used for the purpose of processing video signals and image signals in television technology and video tape recorders (VTRs). A video signal is converted into a digital signal by an A/D converter to be stored temporarily within a serial access memory. Various image processing is carried out to the stored video signals to realize the features of noise reduction and interlace display in image display. This processing gives rise to the need of image processing in a higher speed using field memory. Accordingly, there is a strong demand for improvement in the operation speed of serial access memory. For example, a time period of less than 30 ns is required as the cycle time of a serial out clock signal used for reading in series stored data. Some recently developed field memories have a cycle time as low as 10 ns. The trend in increasing operation speed in serial access memories is expected to grow as the request for high speed operation of image processing becomes great.
FIG. 4 is a block diagram of a field memory showing the background of the present invention. Referring to FIG. 4, this field memory comprises a memory cell array 1 having a plurality of memory cells arranged in rows and columns, a row decoder 2 for selecting an externally specified memory cell row, a column decoder 3 for selecting an externally specified memory cell column, and a sense amplifier 7 for amplifying a data signal read out from a memory cell. A serial selector 8 for data input is connected to column decoder 3.
In writing operation, input buffer 9 receives externally applied serial input data SID1-SID6 to provide the same to a data register 10. Data register 10 holds the applied parallel data to provide the same to memory cell array 1 in response to an output signal generated from serial selector 8. Row decoder 2 selects one word line specified by an externally applied address signal, whereby the data provided from data register 10 is written into one memory cell row.
In reading operation, row decoder 2 selects a word line specified by an externally applied address signal. The data signals stored in the memory cell row connected to the selected word line are applied to a bit line (not shown) and amplified by sense amplifier 7. The parallel data signals amplified by sense amplifier 7 are provided to a data register 4 to be held therein. Serial selector 5 responds to an externally applied serial output clock signal SOC to sequentially select a latch circuit provided in data register 4. In other words, data register 4 responds to a serial selecting signal SS generated from serial selector 5 to provide the held or latched data signal sequentially to a serial bus SB. An output buffer 6 is connected to data register 4 via serial bus SB. Therefore, the data signals read out from a memory cell row in memory cell array 1 are provided as serial output data SOD1-SOD6 via output buffer 6.
The other circuits in the field memory will be explained hereinafter briefly. An instruction/address buffer 11 receives externally applied instruction signals IR1-IR7/address signals A0-A8. The received address signals A0-A8 are applied to row decoder 2, column decoder 3, a row address counter 12 for input, and a row address counter 13 for output. Row decoder 2 responds to a count signal from address counter 12 or 13 to select a memory cell row, i.e., a word line. In refresh mode, row decoder 2 also responds to a count signal from a row address counter 14 for refresh to select a word line. An instruction signal received by instruction/address buffer 11 is held within an instruction register 15. An instruction decoder 16 receives an instruction signal held in instruction register 15 to decode the same. Instruction decoder 16 generates various control signals for the operation of the field memory according to the externally applied instruction. The field memory comprises a timing signal generating circuit 17 for generating a timing signal to operate the above circuits in synchronization.
FIG. 5 is a circuit diagram of memory cell array 1, sense amplifier 7, and data register 4 of FIG. 4. Although FIG. 5 shows the circuits associated with two memory cell columns, only the circuits associated with one memory cell column will be explained to simplify the description. Referring to FIG. 5, a bit line BLa and a bit line BLb form a bit line pair to transmit data signals inverted with respect to each other. An NMOS transistor Q1 is operated in response to a bit line hold signal .phi.1 to hold the potentials of the bit line pair BLa, BLb at a predetermined potential (Vcc/2). In other words, bit line pair BLa, BLb is set to potential Vcc/2 when transistor Q1 is turned on, since signal .phi.2 always has a potential of Vcc/2. An NMOS transistor Q2 is connected between bit lines BLa and BLb to equalize the bit line pair BLa, BLb in response to an equalize signal .phi.3. Dummy memory cells DC1 and DC2 are connected to bit lines BLa and BLb, respectively. Switching transistors Q3 and Q4 are operated in response to dummy word line signals .phi.5 and .phi.4, respectively.
There are two memory cells MC1 and MC3 connected to bit line BLa, and two memory cells MC2 and MC4 connected to bit line BLb. For example, memory cell MC1 comprises an NMOS transistor Q5 for switching and a capacitor C3 for storing a data signal. Transistor Q5 operates in response to a word line signal .phi.7 provided from a row decoder (not shown). Switching transistor Q6 forming memory cell MC2 operates in response to another word line signal .phi.6.
A sense amplifier 7 is constituted by PMOS transistors Q7 and Q9, and NMOS transistors Q8 and Q10. A plurality of sense amplifiers provided along the row direction are activated in response to activation signals .phi.8 and .phi.9. NMOS transistors Q11 and Q12 are connected to the corresponding bit lines of BLa and BLb, respectively, to transmit a bit line signal to data register circuit 4 in response to a transfer signal .phi.10.
One latch circuit forming data register circuit 4 comprises NMOS transistors Q13 and Q15, and PMOS transistors Q14 and Q16. Each of the latch circuits provided along the row direction is connected between power supply potential Vcc and ground potential.
One serial transfer circuit formed by four NMOS transistors Q17-Q20 responds to a serial selecting signal .phi.14 generated from serial selector 5 shown in FIG. 4 to transfer data signals .phi.21 and .phi.21 latched by the aforementioned one latch circuit to serial bus lines SBai and SBbi. In other words, one of transistors Q17 and Q18 is turned on in response to signal .phi.21 or signal .phi.21. Also, transistors Q19 and Q20 are turned on in response to serial selecting signal .phi.14 to provide a data signal latched in the latch circuit to serial bus lines SBai and SBbi.
FIG. 6 is a timing chart for explaining the operation of the circuits of FIG. 5. Referring to FIGS. 5 and 6, the reading operation will be explained hereinafter. Signal IRS in FIG. 6 indicates an externally applied instruction strobe signal. Signal CAS indicates a column address strobe signal. Signal RAS indicates a row address strobe signal. Signal IRE indicates an instruction enable signal. These signals are applied from an external source, as shown in FIG. 4, to control the reading and writing operations of the field memory. In the following description, signals IRS and CAS are represented by signal .phi.23, and signals RAS and IRE are represented by signal .phi.24.
Following the fall of signal .phi.23 at time t1, signal .phi.24 also falls at time t2. Signals .phi.1 and .phi.3 respond to the fall of signal .phi.24 to fall at times t3 and t4, respectively. Transistors Q1 and Q2 are at the ON state since signals .phi.1 and .phi.3 are respectively at logical high (high level) until the respective times of t3 and t4. Therefore, the pair of bit lines BLa and BLb are equalized (set to Vcc/2) till time t4, and then held at a floating state.
At time t5, word line signal .phi.7 rises. Because switching transistor Q5 of memory cell MC1 is turned on in response to signal .phi.7 at a high level, a small potential difference appears between bit lines BLa and BLb. After time t6, activation signals .phi.8 and .phi.9 attain a high level and a low level, respectively, to activate sense amplifier circuit 7. Therefore, the small potential difference between bit lines BLa and BLb is amplified by sense amplifier circuit 7. The rise of transfer signal .phi.10 at time t7 causes transistors Q11 and Q12 to be turned on, whereby the potential difference between bit lines BLa and BLb (i.e. the read out data signal) is provided to latch circuit 4 via transistors Q11 and Q12. Latch circuit 4 latches the applied data signals .phi.21 and .phi.21.
Although the reading operation is described for one memory cell column in the above description, a similar reading operation is carried simultaneously for the other memory columns in memory cell array 1. The data signals read out from each memory cell column are held in the corresponding latch circuit, i.e. in data register 4. The data signals held in data register 4 are serially provided to a serial bus line pair SBai and SBbi in response to a serial selecting signal (for example .phi.14) applied from serial selector 5.
FIG. 7 is a circuit diagram of output buffer 6 of FIG. 4. The field memory of FIG. 4 comprises six serial output data terminals SOD1-SOD6. This means that serial bus SB provided between data register 4 and output buffer 6 comprises six serial bus line pairs. The circuit of FIG. 7 is shown connected to one of the serial bus line pairs, i.e. the i-th serial bus line pairs SBai, SBbi. Serial bus lines SBai and SBbi of FIG. 7 are connected to serial bus lines SBai and SBbi of FIG. 5, respectively.
Referring to FIG. 7, output buffer 6 comprises an equalize circuit 60i for equalizing the serial bus line pair SBai, SBbi, a preamplifier circuit 61i, an inverter circuit 62i, two latch circuits 63i and 64i, and a main amplifier 65i. The output of main amplifier 65i is connected to the i-th serial output data terminal SODi.
Equalize circuit 60i comprises three PMOS transistors Q26, Q27 and Q28 operated in response to equalize signal .phi.19. PMOS transistors Q29 and Q30 are connected between serial bus lines SBai and SBbi and the corresponding data bus lines of DBai and DBbi. Transistors Q29 and Q39 have their gates grounded. A PMOS transistor Q31 for equalization is connected between data bus lines BDai and DBbi. Transistor Q31 is operated also in response to equalize control signal .phi.19.
Preamplifier 61i comprises a current mirror type amplifier 21 and a cross coupled type amplifier 22 each connected to data bus line pair DBai, DBbi. Current mirror type amplifier 21 is formed of PMOS transistors Q32 and Q33, and NMOS transistors Q34 and Q35. Cross coupled type amplifier 22 is formed of NMOS transistors Q36 and Q37. Amplifiers 21 and 22 are activated in response to preamplifier enable signal .phi.18.
Inverter circuit 62i comprises a PMOS transistor Q39 and NMOS transistors Q40 and Q41 connected in series between power supply potential Vcc and ground potential. Transistors Q39 and Q40 have their gates connected to receive data signal DS1 provided from preamplifier 61i. Inverter circuit 62i is activated also in response to enable signal .phi.18. NMOS transistors Q47 and Q48 serving as transfer gates are provided in the preceding stages of latch circuits 63i and 64i, respectively. Transistor Q47 is turned on in response to signal .phi.18. Transistor Q48 is turned on in response to signal .phi.25.
FIG. 8 is a timing chart for explaining the operation of the circuit of FIG. 7. Referring to FIGS. 7 and 8, the operation thereof will be explained hereinafter. Referring to FIG. 8, one stored data signal is read from one memory cell column during one cycle period of a serial out clock signal SOC. It is understood that six data signals are provided simultaneously within one cycle period via serial output data terminals SOD1-SOD6 of the field memory of FIG. 4. In response to serial out clock signal SOC, clock signal .phi.16 is generated. In response to clock signal .phi.16, signal .phi.17 is generated. In response to signal .phi.17, signals .phi.14, .phi.18 and .phi.19 are generated.
Since equalize signal .phi.19 is at a low level before time t21, transistors Q26, Q27 and Q28 forming equalize circuit 60i are at the ON state. Serial bus lines SBai, SBbi are equalized and set to power supply potential Vcc. At time t21, serial selecting signal .phi.14 and equalize signal .phi.19 rise. Transistors Q19 and Q20 of FIG. 5 turned on in response to serial selecting signal .phi.14 of a high level causes a small potential difference between serial bus lines SBai and SBbi. This small potential difference is transmitted to data bus lines DBai and DBbi via transistors Q29 and Q30 of FIG. 7. Transistors Q29 and Q30 are provided for the purpose of increasing the speed of amplification operation of preamplifier 61i.
At time t22, preamplifier enable signal .phi.18 rises. Therefore, current mirror type amplifier 21 and cross coupled type amplifier 22 provided in preamplifier 61i and inverter circuit 62i are activated. This causes the small potential difference on data bus line pair DBai, DBbi to be amplified, whereby the amplified data signal DS1 is provided to inverter circuit 62i.
Data signal DS1 is inverted by inverter circuit 62i to be provided to main amplifier 65i via two latch circuits 63i and 64i. The data signal latched by latch circuit 63i is shown in FIG. 8 as signal DS2. The data signal applied to main amplifier 65i is amplified therein to be provided to an external source via serial out data terminal SODi.
The circuits for generating various clock signals or control signals used to control the above described operations will be explained hereinafter briefly. FIGS. 9-11 are circuit diagrams of control circuits 100, 200, 300 and 400 for generating clock signals .phi.16, .phi.17, .phi.18, .phi.19 and .phi.25. These control circuits 100, 200, 300 and 400 are provided in timing signal generating circuit 17 of FIG. 4.
Referring to FIGS. 9A and 9B, control circuit 100 comprises an input buffer 101 formed by a Schmitt circuit, an NOR gate 102, inverters 103-108, an NOR gate 109, and an NMOS transistor Q42. Input buffer 101 comprises PMOS transistors Q21, Q22 and Q25, NMOS transistors Q23 and Q24, and an inverter 111. Input buffer 101 is connected to receive an externally applied serial out clock signal SOC. Control circuit 100 responds to the applied signal SOC to generate a clock signal .phi.16 having a pulse width determined by a delay circuit formed of inverters 103-104 and a capacitor 110. Since input buffer 101 is implemented by a Schmitt circuit, an output signal having an MOS logic amplitude can be supplied to NOR gate 102, even though the externally applied signal SOC has a TTL amplitude.
Referring to FIG. 10, control circuit 200 comprises NAND gates 201 and 202, inverters 203-209, and a capacitor 210. NAND gate 201 receives clock signal .phi.16 provided from control circuit 100 of FIG. 9. In response to the applied clock signal .phi.16, control circuit 200 generates clock signal .phi.17 having a pulse width determined by a delay circuit formed of inverters 205 and 206, and capacitor 210. Clock signal .phi.17 is used to generate the aforementioned serial selecting signal .phi.14, and is also applied to control circuit 300.
Control circuit 300 comprises an NAND circuit 301, inverters 302-309, and capacitors 310 and 311. Control circuit 300 generates preamplifier enable signal .phi.18 and equalize signal .phi.19 used to control the circuit of FIG. 7.
Referring to FIG. 11, control circuit 400 comprises inverters 401-405, an NAND gate 406, an NOR gate 407, and a capacitor 409. Control circuit 409 responds to clock signal .phi.16 provided from circuit 100 of FIG. 9 to generate clock signal .phi.25 for controlling transfer gate transistor Q48 of FIG. 7.
The frequency of externally applied serial out clock signal SOC is becoming higher to comply with the request of higher operation speed of field memories, as mentioned before. Therefore, the cycle period T of serial out clock signal SOC of FIG. 8 has become shorter, leading to the following problems.
A higher frequency of signal SOC requires a higher frequency of equalize signal .phi.19 for equalizing serial bus lines SBai and SBbi. This means that the equalize time period Te of FIG. 8 (i.e. the time period of signal .phi.19 at a low level) becomes shorter. The equalizations of serial bus lines SBai and SBbi, and data bus lines DBai and DBbi may not be carried out sufficiently during this shorter equalize time period Te. Particularly, the long wiring length of serial bus lines SBai and SBbi is responsible for the charging/discharging of equalization requiring a long time period. Erroneous reading will occur if preamplifier 61i commences the next amplifying operation in response to enable signal .phi.18 in the case where serial bus lines SBai and SBbi are not yet completely equalized. More specifically, the preceding read out data signal remains on serial bus line pair SBai, SBbi because serial bus lines SBai and SBbi are not equalized sufficiently. The newly read out data signal will be affected by the remaining data signal to result in erroneous reading.

Serial access memory comprising disconnecting circuit between serial bus lines and preamplifier


A bar clamp including a first bar member and a second bar member with the second bar member telescoping out from the first bar member. A securing mechanism, such as a pin in the first member, releasably secures the members together at a preferred telescoping position. The second bar member has a jaw member that can be advanced or retracted by means of a linear actuator and the first bar member has a jaw member that can be adjusted by positioning the cam-action locking mechanism in one of the notches disposed along the length of the first bar member. As a result of the telescoping relationship of the bar members, workpieces of varying sizes may be clamped between the jaw members without the need of multiple bar clamps of varying lengths.

Bar clamps are well known in many applications, including to the construction industry as well as to craftsmen, for use in holding a work piece in a fixed position. Typically, a bar clamp is used to hold multiple objects together for gluing, welding, or other purposes where it is advantageous to temporarily retain the multiple objects comprising the workpiece in a fixed position.
A bar clamp secures workpieces between the clamp's moveable arms. Different size workpieces can be accommodated by adjusting the clamp's jaw members along the length of the bar. A given bar clamp can accommodate workpieces ranging in size from a very small piece when the jaw members are disposed close together, up to a large piece when the jaw members are at opposite ends of the bar. The largest workpiece a bar clamp can accommodate is typically slightly smaller than the length of the bar. Working on projects with greatly varying workpiece sizes requires the purchase of multiple bar clamps since many larger objects will be larger than the operative length of a standard bar clamp, requiring the use of a longer bar clamp. However, overly long bar clamps are more expensive and their use can also be more difficult and/or clumsy than a shorter bar clamp.
The effective use of bar clamps in construction and craft wherein workpieces are of widely varying sizes require the use of multiple bar clamps. Manufacturers must fabricate and then ship the different length bar clamps. Switching manufacturing between different length bar clamps breaks up assembly line production. Shipping the longer bar clamps is inefficient and expensive because of the increased volume of each clamp, raising shipping costs and resulting in the shipment of fewer pieces in each shipping container. Hardware stores must stock larger inventories of bar clamps in order to have at least a few of each size on hand to accommodate the needs of their clientele. Workmen must purchase, and then find a way to transport and store, multiple bar clamps of varying lengths in order to ensure that the proper equipment is on hand at each project.
After the manufacturing cost, typically the single largest cost of getting a good to market is shipping. The more space-efficiently a product can be packed, the greater the savings to the manufacturer, and in turn, the consumer. Similarly, storage space is often a big factor in consumer purchasing decisions. Lengthy and unwieldy bar clamps can result in the use of incorrectly-sized bar clamps or abandonment of a project rather than consumer purchase of an unwieldy and limited-use extra-long bar clamp.


An apparatus and method for calibrating a PTO for driving a cutter of a header of an agricultural windrower, wherein a programmable control module in connection with at least signal operated device in operative control of a variable displacement pump operable for controlling operation of the PTO, is programmed as part of an automatic calibration routine for directing signals to the device having values which will increase over time from a first value toward a second value. At the same time, the control module determines when a first movement of the cutter occurs. If the first movement occurs before the second signal value is reached, information representative of an electrical signal corresponding to the first movement is stored. The routine is then repeated using a higher range of electrical signal values to calibrate where the cutter reaches max speed. In either instance, if the speed condition is not reached with the outputting of the signals within the range, the calibration fails.

U.S. Pat. No. 6,901,729, is incorporated herein by reference in its entirety. This patent describes a header flotation system that is referred to as "non-independent". U.S. Provisional Application No. 60/699,492, filed Jul. 15, 2005, is also incorporated herein by reference in its entirety.
A windrower typically consists of a self-propelled tractor or similar vehicle, and a cutting mechanism which is either towed by the tractor or carried thereby. The cutting mechanism carried by a windrower is typically referred to as a header, and is supported on the windrower by forwardly projecting arms. Briefly, the arms comprise elements of a lift and flotation mechanism or mechanisms operable for setting a height of the header above the ground or other surface over which the windrower moves, the flotation permitting the header to ride lightly up and over rises in the terrain during field operation.
Headers are typically available and a variety of configurations. Common elements of different headers include cutters operable for severing crops from the field. One typical cutting mechanism is a sickle cutter which includes a row of knives which extend across the width of the header and which are powered to move reciprocally sidewardly relative to a sidewardly extending array of fixed knives or bars, thereby effecting a cutting action. Another cutting mechanism is a disk cutter including a sidewardly extending array of rotatably driven disks having knives extending radially outwardly from the outer circumferential edges thereof, the rotation of which disks effects the cutting action. Both of these types of cutters may be provided in different overall sideward widths. A typical cutting speed for a sickle type cutter is about 1500 to 1800 strokes per minute, and the for a disk cutter, about 2200 to 3200 rpm. It is typically desirable for the cutters to operate at a constant speed, but, in operation, the cutting speed may vary as a result of changing conditions such as crop population, contact with the ground, or the like. Closed loop speed control is typically used to maintain a consistent cutting speed under varying loads and engine speed changes.
The cutters are powered using a fluid drive, such as a fluid power takeoff (PTO). A pump driven by the engine of the tractor provides pressurized fluid to the PTO system. The pump can be of a fixed displacement, or variable displacement, in the latter instance, the pressurization and direction of fluid flow, and thus the speed and direction of operation of the PTO, being controlled by solenoids. Varying electrical current signals would be utilized for operating the solenoids, for operating the cutters at the desired speed and in the desired direction. In order to achieve maximum response time from the closed loop speed control system, it is desired to eliminate the variations in offset and gain of the electrically controlled pump.
Therefore, it would be desirable to have an apparatus and method which enables calibrating PTO current values on the vehicle, taking into account associated system variances, and furthermore to do this with minimal operator intervention.

Apparatus and method to calibrate the PTO with the disk or sickle of an agricultural windrower


In order to obtain further instruction from connected ISDN terminals, a service resource function is provided. The function is responsive to data carried over a separate data network to provide a prompt and collect service to a user of ISDN. The invention allows the addition of prompt and collect services such as account allocation to be provided.

1. Field of the Invention
The present invention relates to telecommunications networks and more particularly to telecommunications networks of the kind requiring communications between the network and terminals attached thereto without provision of a voice communications path at the initial phase of a communications call.
2. Related Art
Many services provided by telecommunications networks will require information additional to a telephone number for example to enable completion of a connection through the transport network. For example, credit or charge card calls may require entry of a personal identification number (PIN) and/or an account number prior to proceeding. Where such services are provided after the customer has been connected through the network to a peripheral a voice or other prompt may be used to request the customer to enter further detail. Such services are therefore often referred to as xe2x80x9cprompt and collectxe2x80x9d services.
Where a customer has a telephone instrument or other terminal adapted to signal the network by use of multi-frequency tones, it is possible for the prompt and collect service to operate by the coding of the tones without establishing a complete speech path through the network. However, many communications connections are not by way of analogue lines to the customer""s premises but are rather of a digital type and, more particularly, of a type known as ISDN in which a single customer connection carries a plurality 64 Kbs digital bearer channels and a data channel.
ISDN terminals do not function efficiently in the provision of multi-frequency tones until the terminal is put into. a speech phase. However, putting the call into the speech phase prior to effecting a connection simply to enable prompt and collect services to operate may result in charging difficulties as the customer equipment may see a network response as a valid answer.
Further, if the ISDN call originates from a data terminal, ISDN standards do not permit switching back to a data phase after switching into voice phase communication. In many cases also data terminals may not include multifrequency transmission capability and/or may not include speaker or headset facilities to receive voice prompts.
According to the present invention there is provided a telecommunications network including switch means which have customer connections which receive a bit stream from customers, the bit stream comprising the plurality of bearer channels and at least one data channel, control means of the switch being responsive to data from the data channel to set up bearer channel calls through the network, and network control means responsive to stored data associated with a calling connection identity or a called connection identity to accept data from another data network in respect of bearer channel calls.
Preferably the switch includes means responsive to a portion of the data transmitted in the data channel to forward received data either to control means of the switch or to a data network.
The data network may be of the kind referred to as an X25 network which may be the network from which the network control means recovers data.
The service control means may be arranged to cause means connected to the data network to transmit prompt information by way of the data network to the calling connection to prompt a user to forward further information by way of the data network.
In an alternative arrangement the data network may be an electronic mail type environment in which messages are transferred to an E-mail address of the network, apparatus associated with the service control function having an appropriate address to which mail relating to the bearer channel may be transmitted. The resource function associated with forwarding prompt data may forward prompt data to an E-mail address requiring a reply from the user.
According to a feature of the invention there is provided a digital telecommunications network having a plurality of switching units for providing transmission of digital bearer channels between first and second selectable service points, the second service point being determined by data from a data channel transmitted from the first service point, control means of the network being responsive to data identifying the first or second service points to provide additional functionality of the kind requiring further defining data from the first service point characterised in that an interface is provided between the control means of the network and a separate data network for providing transmission of data channels, the interface being responsive to the control means to transmit prompting data to the first service point by way of the data network and to collect data returned thereby for transmission to the control means such that completion of a call through the first network is modified by data received through the second network.

British Telecommunications public limited company


A thermal transfer material is described herein that includes: a heat spreader component, wherein the heat spreader component comprises a top surface, a bottom surface and at least one heat spreader material, and at least one solder material, wherein the solder material is directly deposited onto the bottom surface of the heat spreader component. Methods of forming layered thermal interface materials and thermal transfer materials include: a) providing a heat spreader component, wherein the heat spreader component comprises a top surface, a bottom surface and at least one heat spreader material; b) providing at least one solder material, wherein the solder material is directly deposited onto the bottom surface of the heat spreader component; and c) depositing the at least one solder material onto the bottom surface of the heat spreader component.

Electronic components are used in ever increasing numbers of consumer and commercial electronic products. Examples of some of these consumer and commercial products are televisions, personal computers, Internet servers, cell phones, pagers, palm-type organizers, portable radios, car stereos, or remote controls. As the demand for these consumer and commercial electronics increases, there is also a demand for those same products to become smaller, more functional, more cost efficient and thermally efficient, and more portable for consumers and businesses.
As a result of the size decrease in these products, the components that comprise the products must also become smaller, better manufactured and better designed. Examples of some of those components that need to be reduced in size or scaled down are printed circuit or wiring boards, resistors, wiring, keyboards, touch pads, and chip packaging.
Components, therefore, are being broken down and investigated to determine if there are better building materials and methods that will allow them to be scaled down and/or combined to accommodate the demands for smaller electronic components. In layered components, one goal appears to be decreasing the number of the layers while at the same time increasing the functionality and durability of the remaining layers, decreasing the production steps and increasing the cost efficiency. These tasks can be difficult, however, given that the number of layers cannot readily be reduced without sacrificing functionality.
Also, as electronic devices become smaller and operate at higher speeds, energy emitted in the form of heat increases dramatically. A popular practice in the industry is to use thermal grease, or grease-like materials, alone or on a carrier in such devices to transfer the excess heat dissipated across physical interfaces. The most common types of thermal interface materials are thermal greases, phase change materials, and elastomer tapes. Thermal greases or phase change materials have lower thermal resistance than elastomer tape because of the ability to be spread in very thin layers and provide intimate contact between adjacent surfaces. Typical thermal impedance values range between 0.1-1.6° C. cm2/W. However, a serious drawback of thermal grease is that thermal performance deteriorates significantly after thermal cycling, such as from 65° C. to 150° C., or after power cycling when used in VLSI chips. It has also been found that the performance of these materials deteriorates when large deviations from surface planarity causes gaps to form between the mating surfaces in the electronic devices, or when large gaps between mating surfaces are present for other reasons, such as manufacturing tolerances, etc. When the heat transferability of these materials breaks down, the performance of the electronic device in which they are used is adversely affected.
Organic pastes and epoxies are also being used to facilitate heat removal from the component. One example of this use is applying the organic paste and/or epoxy to the interface between the silicon and a heat spreader, such as a nickel plated copper spreader. These pastes and epoxies are normally filled with metal or other thermally conductive particles to improve heat transfer. As components are becoming smaller and more complex, the amount of heat to be removed has increased to the point where solid metal thermal interface is necessary. In most conventional applications, the solid metal thermal interface is a solder material of melting point 140-200° C.
As more solder materials are being utilized in components to dissipate heat, it has been discovered that it is difficult to solder to nickel without the use of a material, such as a flux, because of the production of detrimental nickel oxides at the solder-nickel interface. One recent approach to completing the solder joint without the use of a flux is to electrodeposit a gold spot on the precise location where the solder joint is to be formed. This approach is described in U.S. Pat. No. 6,504,242 issued to Deppisch et al. (Jan. 7, 2003). While this approach works well functionally, the value of gold contained within the spot is detrimental to the cost efficiency of the components. Furthermore, in order to complete a joint having a gold spot or gold interface, there are at least two process steps necessary—deposition of the gold and application of the solder material. These additional process steps are not only costly, but slow.
Thus, there is a continuing need to: a) design and produce thermal interconnects and thermal interface materials, layered materials, components and products that meet customer specifications while minimizing the size of the device and number of layers; b) produce more efficient and better designed materials, products and/or components with respect to the compatibility requirements of the material, component or finished product; c) develop reliable methods of producing desired thermal interconnect materials, thermal interface materials and layered materials and components/products comprising contemplated thermal interface and layered materials; d) develop materials that possess a high thermal conductivity and a high mechanical compliance; and e) effectively reduce the number of production steps necessary for a package assembly, which in turn results in a lower cost of ownership over other conventional layered materials and processes.

Thermal interconnect systems methods of production and uses thereof


A process for improving the recovery of solid triphenylboron-pyridine compound (TPBP), while retaining desirable particle characteristics comprises the addition of an acid to neutralize at least a portion of the alkali contained in the aqueous mother liquor. By adjusting the pH of the product slurry to between about 8.5 and about 12, it is possible to increase product recovery by more than 10%, while maintaining desirable particle characteristics.

Triphenylboron-amine compounds, and triphenylboron-pyridine (TPBP) compounds in particular, are known to be effective biocides and marine anti-fouling agents and are, therefore, commercially important products. See for example U.S. Pat. No. 3,211,679.
One method for making TPBP is by the reaction of TPBA with pyridine in aqueous solution. See JP 08311074 (the "JP 1074 Application") and U.S. patent application Ser. No. 11/473,907 filed Jun. 23, 2006 (the "'907 application"), both incorporated herein by reference. Solid TPBP particles precipitate out when TPBA is reacted with pyridine.
However, after addition of pyridine to the aqueous TPBA, the resulting product slurry contains three moles of alkali (e.g., alkali metal hydroxide) for every mole of TPBP. Since the solubility of TPBP in an aqueous solution increases with increasing concentration of alkali, a considerable amount of the product TPBP is dissolved in the mother liquor.

This patent is subject to a terminal disclaimer.

Process for making triphenylboron-pyridine compound


A method for producing a protective coating on the surface of a carbonaceous substrate is described. A substantially uniform coating of a liquid or solid precursor material is provided on the surface of the substrate. The precursor material is one which has boron-oxygen bonds and is substantially non-reactive with the substrate at a first relatively low temperature and is capable of reacting with the substrate at a second temperature which is substantially higher than the first temperature. The substrate is then raised to the second temperature to react the coating with the substrate to form a porous region of substantially uniform depth in the substrate surface. This region contains interconnecting interstices and boron carbide. The interconnecting interstices are then at least partially filled with a glass forming material such as boron, boron oxide, boron carbide, silicon, silicon alloy, silicon dioxide, silicon nitride, silicon oxynitride, germania, and mixtures thereof. A refractory coating may then be deposited on the filled layer. Also described is a coated article produced in accordance with the described method.

The desirability of providing carbon bodies having oxidation resistance is well-known. Carbonaceous materials such as monolithic carbon, graphite, and carbon-carbon composites of fibers in carbon have excellent strength-to-weight properties at high temperatures, e.g., 1400.degree. C. and higher, and are generally superior to conventional construction materials such as metals and super alloys at these temperatures. In addition, the mechanical strength of a carbon body increases as the temperature increases, whereas in conventional structural metals, the strength typically decreases with increased temperature.
The use of carbon bodies in high temperature applications has been limited due to the relatively high reactivity of carbon, principally with oxygen, at temperatures above about 400.degree.-500.degree. C. Such reactivity results in erosion of the carbon body due to the reaction between carbon and oxygen, yielding carbon monoxide and carbon dioxide. Accordingly, many attempts have been made to provide oxidation-resistant coatings for carbon bodies in order to permit their use in oxidizing environments and at elevated temperatures.
Major difficulties have been encountered in attempting to provide oxidation-resistant coatings on carbon bodies. One difficulty is that the coefficient of expansion of the carbon body may be very different from that of the oxidation-resistant coating. The stresses that result from different coefficients of expansion between the coating and the underlying carbon body cause cracking or rupture of the coating, particularly when the part is subjected to thermal cycling. When the coating integrity is thus compromised, oxygen penetrates the coating and attacks the underlying carbon body with resulting loss of structural integrity.
Surface porosity in the carbon body, which results from articles which are not fully densified, may cause pinholes to form in the coating during the coating process. This also may allow oxygen to penetrate to the carbon body. It has also been found that mechanical vibration, debris impingement, and the like may cause cracking of brittle protective coatings.
Successful resistance to high temperature oxidation may be achieved by the process disclosed in U.S. Pat. No. 4,515,860, which is incorporated herein by reference. The oxidation-resistant carbon body disclosed in this patent has thermochemically deposited thereon a silicon alloy coating containing one or more alloying elements selected from the group consisting of carbon, oxygen, aluminum, and nitrogen. The amount of silicon in the coating is in excess of the stoichiometric amount and the alloy coating has a non-columnar grain distribution having substantially equiaxial grains of an average diameter of less than one micron. Because of the exceptionally fine grain size and even grain distribution in the coating, any cracks that may occur are extremely fine in width and form a mosaic pattern. The amount of silicon in excess of the stoichiometric amount fills in these fine cracks when the carbon body is heated to above the melting point of silicon, e.g., above 1410.degree. C., and reacts with any oxygen to form a glassy silicon oxide which acts as a filler sealing the cracks. This patent also contemplates, on an optional basis, particularly where lower temperature crack-resistance is desired, providing an intermediate boron layer. Boron reacts with oxygen to form a glassy boron oxide sealant and flows into any cracks that have formed. In commercial practice the carbon body is usually provided with a preliminary treatment in a mixture of chromic acid and sulfuric acid.
The oxidation resistance conferred by the coatings described in U.S. Pat. No. 4,515,860 provides significant superior characteristics as compared to the coatings of the prior art. Under some circumstances, however, particularly where severe temperature cycling occurs, the protection system may be inadequate to properly seal the cracking which occurs in the brittle coating such that the carbon body is subjected to oxidative attack.
In U.S. patent application Ser. No. 873,004, a coated carbon body is described having improved resistance to oxidation over wide temperature ranges including low temperatures of 500.degree.-1000.degree. C. and high temperatures in excess of 1400.degree. C. The carbon bodies produce by the methods described therein also exhibit excellent oxidation resistance even in environments that involve high temperature thermal cycling. In addition, such carbon bodies exhibit excellent resistance to ablation and erosion.
In the aforesaid patent application, a carbon body is heated to an elevated temperature, generally above 1500.degree. C., and is exposed to preferably gaseous boron oxide. The resulting gas-solid reaction causes the surface of the carbon body to become etched and results in the formation of boron carbide which is contained in the converted and etched surface. The etched and converted surface zone is about 2 to 250 microns deep and is characterized by interconnecting interstices. Following formation of the etched surface, the converted carbon body is provided with a glass forming coating, at least a portion of which is within the interconnecting interstices. The glass forming material may be selected from the group consisting of boron, boron oxide, boron carbide, silicon, silicon alloy, silicon dioxide, germania, and mixtures thereof.
In U.S. patent application Ser. No. 131,479, a continuation-in-part application to Ser. No. 873,004 referred to above, silicon nitride and silicon oxynitride are disclosed as additional glass forming materials.
It has been found that, under certain circumstances, the use of a gaseous boron oxide reactant in the foregoing described method may be difficult. For example, on carbonaceous substrates having complex geometric shapes of, it may be difficult to control the uniformity of the surface etching and conversion. This difficulty is attributable to the formation of concentration gradients of boron oxide present in the gas phase treating the carbon material. In addition, velocity gradients in the fluid flow patterns surrounding the substrate may also contribute to non-uniformity. Moreover, more than one high temperature treatment may be required to form the desired conversion layer in the substrate since certain areas which are poorly exposed to the reactant gas may remain unetched or poorly etched. The foregoing difficulties also make it difficult to scale up the process to accommodate large components, since flow conditions and concentration gradients may be affected as a result of the scale up.

Coated carbonaceous articles and method for making same


A pressurized fluid cast for stabilizing a broken bone of a patient includes a sleeve having an inner wall and an outer wall with a fluid cavity between the inner and outer walls. The outer wall has at least one access port established therethrough. The sleeve is configured to be placed at a limb of a patient such that the inner wall circumscribes the limb and is disposed at least partially along the limb, with the fluid cavity and the outer wall being radially outward of the inner wall. The sleeve is adaptable to accommodate a particular patient injury and limb. Fluid is provided within the fluid cavity and is pressurized to a selected pressure to apply substantially uniform pressure at the limb of the patient. An outer protective shell may be provided at least partially around the sleeve to limit puncturing of the sleeve.

Currently casts for immobilizing or stabilizing a patient's injury are made using either plaster or fiberglass (where the material is molded over the patient's arm or leg or the like to immobilize the injury) or are premade in generic variable adjustable sizes. The fit of a plaster and/or fiberglass cast is dependent on the skill of the medical provider and even a skilled provider may not be able to fit a cast perfectly as soft tissue swelling may be variable during the time of healing. The variability in fit decreases the comfort during the healing process and can delay the healing process and/or may cause iatrogenic infection or other soft tissue damage, such as compartment syndrome or the like, if the cast is too tight and cuts off circulation to a distal extremity. Changes in swelling, comfort issues or other concerns may require that a second cast or even a third cast be placed or the placement of the cast may be delayed to allow for soft tissue swelling to go down.
These issues increase medical costs to the patient and insurance company due to increased provider time with the patient. In addition, there is an increased cost to society due to delay in return to work due to pain, disability, increased office or procedure visits and increased length of healing time. While some adjustable casts have been proposed that may be adjusted to adapt to changes in swelling, such proposed casts do not provide enough stability for many types of fractures.


An ultrasonic welding probe power supply for powering more than one ultrasonic welding probe with power is provided. The power supply is adapted to provide power only to one welding probe at a time. A ringdown period is monitored between termination of provision of power to a first probe and the initiation of provision of power to a second probe during which provision of power to the second probe is disabled. Circuitry is provided within an ultrasonic welding probe controller to monitor probe activity and to control the interval between termination of provision of power to one probe and the initiation of provision of power to a second probe so that efficient and safe switching is made among ultrasonic probes.

Ultrasonic welding is an efficient technique for joining component parts in manufacturing environments. Applications of ultrasonic welding include the welding of plastic parts and fabrics when manufacturing products such as automobile components, medical products, and hygiene products.
Manufacturers who employ ultrasonic welding may use several individual welding devices, or "probes," in a single manufacturing environment. Individual devices may be customized for particular welds or for use on particular components. It is desirable, from a cost standpoint and also given the motivation to conserve space in a manufacturing environment, to use a minimum of power supplies to power an appropriate number of ultrasonic probes.
To achieve maximum power transfer efficiency (of greater than approximately 90%) from an ultrasonic generator to an ultrasonic load, such as a probe, the generator must drive the ultrasonic load at the load's exact mechanical resonant frequency. Circuitry inside the generator allows the generator drive frequency to track the load resonant frequency, which drifts due to temperature variations and may also be caused by the aging characteristics of the ultrasonic transducer or driver.
Powering more than one ultrasonic load from one ultrasonic generator output at one time can cause an overload condition on the output of the generator, because it is not possible to match the resonant frequency of multiple probes exactly. The resonant frequencies of two probes will change over time because different ultrasonic probes age differently over time and the temperature changes they experience will not match over time. Thus, to power multiple probes from one generator output, the probes should be individually switched to the high voltage (typically greater than 1,000 Vrms) generator output. This may be accomplished by using multiple high-voltage relays, with one relay dedicated to each ultrasonic load.

Multiple probe power systems and methods for ultrasonic welding


A radar system having first and second modes of operation comprising a dual antenna assembly comprising first and second antennas having respective first and second antenna waveguides coupled to a waveguide switch operable to divert RF energy to or from either said antenna waveguide, said waveguide switch coupled to a common waveguide, said dual antenna assembly mounted to an antenna support assembly, said first and second antennas being designed for use in said first and second modes respectively and operable for coupling said RF energy to a transmit medium, and for coupling reflected RF energy from transmit medium to said first or second antenna waveguide; and a control processor configured with control logic operable to control the functions of said radar system wherein said first and second antennas are mounted generally perpendicularly in the vertical plane with respect to each other and wherein said radar system operates in only one of said modes of operation at any time.

1. Field
The present invention relates generally to radar systems, and, in particular, to radar systems having dual modes, and still more particularly, to radar systems having a weather radar mode and an air surveillance mode.
2. Description of the Related Art
Since the invention of detection and ranging using radio frequencies, different radar systems have been developed to meet the requirements of detecting different phenomena or objects. All radars work on the same basic principles of transmission of RF energy into the transmission medium (for example, the atmosphere), reception of reflected energy, (also known as backscatter or return energy), and analysis of the received energy to determine the presence and possibly characteristics of the detected object(s). Each type of radar system is optimized for the targets sought to be detected by the radar.
For example, weather radar systems are tailored to detect airborne precipitation, known in the art as hydrometeors. Many weather radars operate in the radar frequency bands and wavelengths that require large antennas and may preferably be horizontally polarized to better detect falling hydrometeors. On the other hand, other radars, for example, air surveillance radars tend to be horizontally linearly, and may be circularly polarized in order to reject returns due to weather in the scan volume. Analysis of the return energy has long been performed by computer processors configured with software that is specifically developed to process the data represented by the received energy.
Being able to detect both weather and air targets meant multiple radar systems, i.e., a weather radar and a separate air surveillance radar, co-located at or near a site of interest. Each separate system would mean installation and operation of separate hardware (antenna, transmitter, receiver, computer processors, power supplies and displays), and separate software modules installed in those systems. This requires sufficient space to install and operate such hardware. It also results in increased costs for the hardware and its maintenance.
Multi-mode radars have been developed to provide detection capability of differing object types in a limited space. For instance, modern fighter aircraft (third generation and beyond) employ radars with multi-mode capability. There is an air-to-air radar for detection of airborne targets, and an air-to-ground radar for air-to-surface weapons targeting. The former may be pulsed, doppler, or pulsed-doppler, while the latter may be a pulse only synthetic aperture radar. There have been radars fielded that incorporate two antennae; one for search and detection, and the second for weapons guidance.
These radars however are only examples of achieving multi-mode capability in the confines of a small air platform. Heretofore, there is not a successfully deployed multi-mode radar for use at air fields, for example, that need a weather radar in addition to air surveillance capability.

Dual mode weather and air surveillance radar system


A charged-particle beam apparatus is provided with a cathode to emit charged particle beams, an anode to propagate the charged particle beams emitted from the cathode in a sample surface direction, an aperture to propagate a charged particle beam passing through an opening at a predetermined position and of a predetermined shape, among the charged particle beams passing through the anode, in the sample surface direction, and a first electrode that is disposed between the anode and the aperture, and is set at a first electric potential of a polarity repelling a polarity of an ion generated due to collision of a charged particle beam.

A writing apparatus using a charged particle beam such as an electron beam is used in a highly-integrated semiconductor fabrication process and the like, because of its intrinsically excellent resolution performance. In this type of writing apparatus, the charged particle beam is irradiated to a sample surface to form a pattern on the sample surface. In the pattern formation, an irradiation time to irradiate the charged particle beam to the sample surface becomes shorter as the current density on the sample surface is higher, thereby improving a writing throughput.
In order to have higher current density on the sample surface, the charged particle beam has to be heated to a high temperature. However, when a cathode is set at a high temperature, evaporation of a cathode material is accelerated, so that the cathode tip shape is changed during writing, thereby shortening the cathode's lifetime.
As explained above, although when the writing throughput is improved, the cathode's lifetime tends to be shortened, there is another factor for shortening the cathode's lifetime. When an electron beam collides with a current limiting aperture and the like, a gas is discharged and is ionized by secondary electrons, scattering electrons, etc., and the ions collide with the cathode, thereby accelerating the cathode's exhaustion.

Charged-particle beam apparatus, charged-particle beam writing apparatus, and charged-particle beam controlling method


A variable gas turbine compressor vane assembly comprising a case structure comprising a cavity. A compressor vane is at least partially disposed inside the cavity in the case structure. The portion of the compressor vane is rotatably supported inside the cavity. A wear coating is disposed on at least a portion of a surface of the compressor vane. An antifriction coating is disposed on the wear coating. A bushing is disposed between the antifriction coating and the case structure. The bushing is in sliding contact with each of the antifriction coating and the case structure. The antifriction coating maintains a coefficient of friction between the antifriction coating and the bushing of equal to or less than about 0.95 in atmospheres substantially devoid of water vapor.

This invention relates generally to gas turbine engine variable stator vane assemblies and, more particularly, to wear resistant coatings used within the variable stator vane assembly.
In a gas turbine engine, air is drawn into the front of the engine, compressed by a shaft-mounted compressor, and mixed with fuel. The compressor is made up of several rows or stages of compressor stator vanes and corresponding rows or stages of compressor rotor blades there between. The stator vane rows are situated between the rotor blade rows and direct airflow toward downstream rotor blades on the rotor blade row. After leaving the compressor, the air/fuel mixture is combusted, and the resulting hot combustion gases are passed through the turbine section of the engine. The flow of hot combustion gases turn the turbine by contacting an airfoil portion of the turbine blade, which in turn rotates the shaft and provides power to the compressor. The hot exhaust gases exit from the rear of the engine, driving the engine forward. Optionally, a bypass fan driven by a shaft extending from the turbine section, which forces air around the center core of the engine and provides additional thrust to the engine.
To increase the operating capacity of the compressor, at least some of the compressor stator vane rows are designed with vanes that can rotate in around an axis that is in its longitudinal direction to adjust the angular orientation of the vane with respect to the airflow traveling through the compressor. The adjustment of the angular orientation allows control of the amount of air flowing through the compressor. Variable stator vane designs typically allow for about 45° rotation of the stator vane to optimize compressor performance over the operating envelope of a gas turbine engine. The variable stator vane structures include an outer trunnion disposed in a complementary mounting boss in the stator casing for allowing rotation of the vane relative to the casing. A lever arm is fixedly joined to a coaxial stem extending outwardly from the vane trunnion. The distal end of the lever arm is operatively joined to an actuation ring that controls the angle of the vane. All of the vane lever arms in a single row are joined to a common actuation ring for ensuring that all of the variable vanes are positioned relative to the airflow in the compressor stage at the same angular orientation.
A known variable stator vane assembly includes a bushing and washer disposed between a trunnion attached to a variable vane and a casing. The bushing and washer decrease the coefficient of friction between the trunnion and the casing and facilitate rotation of the vane, through the trunnion. The bushing and washer also help prevent wear of the trunnion and casing. A shroud may also be place between the trunnion and casing to prevent wear.
A number of structures in the gas turbine engine, including the bushing and washer structures, used with variable stator vanes are subjected to conditions of wear at temperatures ranging from low temperatures to highly elevated temperatures. In addition, the bushing and washers are subject to high altitude atmospheres. In addition to low temperatures, high altitude atmosphere includes little or no water vapor. Water vapor is required for conventional graphite containing lubricants to maintain lubricity.
Wear occurs when contacting surfaces of two components rub against each other. Typical results from wear include scoring of one or both surfaces, and/or material removal from one or both surfaces. In the bushing and washer system of the variable stator vane assembly, scoring may occur on one or both of the surface trunnion and the casing, both of which are expensive to repair and/or replace. As the surfaces are damaged, they become even more susceptible to the effects of wear as their effective coefficients of friction rise and wear debris is trapped between the wearing surfaces, so that the wear damage accelerates with increasing time in service. Wear debris may include material removed from the wearing surfaces due to wear, or may include foreign particles, such as dust or debris from the air traveling through the engine.
The wear conditions sometimes arise because it is not desirable or possible to firmly affix the two components together to prevent the rubbing action, because of the functionality of the components. An example is a cylindrical bushing used to support a variable stator vane in the compressor section of the gas turbine engine where the element inserted into the bushing (e.g., the vane trunnion) rotates or slides in contact with the surface of the bushing.
When a bushing and washer system fails due to excessive wear, serious problems for the gas turbine engine compressor may occur. The failure of the bushing and washer may create an increase in leakage of compressed air from the interior of the compressor through the variable stator vane assembly, which results in performance loss for the compressor. In addition, failure of the bushing and washer can result in contact between the stator vane and the casing, which causes wear and increases overhaul costs of the engine.
One known material for fabrication of bushing for variable stator vane assemblies is a specially developed composite of carbon fiber reinforcing rods in a polyamide resin matrix manufactured by E. I. Du Pont De Nemours and Company of Wilmington, Del. The bushings are commonly known as VESPEL®CP™ bushings. VESPEL® and CP™ are trademarks that are owned by E. I. Du Pont De Nemours and Company. The polyamide resin used in the VESPEL®CP™ bushings is commonly known as NR150™. The NR150™ trademark is owned by Cytec Technology Group of Wilmington, Del. Although the VESPEL®CP™ bushings have an extended life at temperatures 450–500° F. (232–260° C.), the VESPEL®CP™ bushing have an upper temperature limit of 600° F. (316° C.). Extended operation at temperatures at or above 600° F. (316° C.) limit their operational life. The polymer bushings do not withstand the combinations of high temperature and vibrational loading experienced in the operation of the gas turbine engine well, leading to a relatively short part life.
Another known method for reducing wear on the variable stator vane assembly is placing a carbon-containing antifriction coating on a surface in the variable stator vane assembly. This antifriction coating is a coating fabricated from a material that reduces the coefficient of friction between the surface of the trunnion and the surface of the casing. One carbon-containing component known for antifriction coating is graphite. However, graphite has the disadvantage that water vapor is required to maintain lubricity. Atmospheres at aircraft cruise altitudes do not have enough water vapor present for graphite to be lubricious. Graphite also has the disadvantage that graphite has poor tribological properties in applications that require reciprocating motion. An additional disadvantage of graphite is that graphite begins to oxidize rapidly at temperatures at or greater than 500° C. (932° F.). Some variable stator vane systems may experience temperatures in excess of 500° C. (932° F.). Therefore, a replacement material for graphite in antifriction coating is needed.
Attempts have also been made to coat the stator vane trunnion with a single wear coating. The single wear coating attempts to incorporate the low coefficient of friction materials known in the art with hard, smooth wear resistant coating materials into a single coating on the vane trunnion. However, the single wear coating lacks the ability to maintain the properties of each of the individual components (i.e., fails to maintain both low coefficient of friction and wear resistance). In other words, the single wear coating does not provide all of the desired tribological properties (e.g., reduce wear and low coefficient of friction) required for extended operation of variable stator vanes subject to conditions of high temperature, vibration and high altitude atmospheres.
There is accordingly a need for an improved approach to the protection of gas turbine components, such as variable vane trunnion surfaces, variable vane casing surface or other surfaces in the gas turbine engine against the damage caused by wear. The present invention fulfills this need, and further provides related advantages.

Wear resistant variable stator vane assemblies