An improved differential source follower with negligible input/output mismatch over a wide range of input signal magnitudes. A pair of FETs and current sources provides bias current control for each differential output that cancels the inherent body-source voltage variation of the source followers which acts to attenuate the unity gain output signal.

1. Technical Field of the Invention
This invention generally pertains to analog signal processing circuits. In particular, this invention is directed to an improved input buffer circuit providing improved performance over a wider range of input signal levels.
2. Background Art
Analog signal processing circuits often require unity gain buffers at their inputs to minimize loading on the circuit which drives them. A method of implementing such a buffer is to use a single device unity-gain amplifier such as a source follower or common drain transistor. In such a configuration, the source is typically biased with a DC current of 10 to 100 .mu.A, the input signal is applied to the gate, and the output appears at the source, shifted by a voltage equal to the V.sub.GS of the device at the given bias level.
A problem occurs with this circuit because the shift voltage V.sub.GS is a function of the threshold voltage of the device. Since the device threshold is a function of its source-body voltage (i.e., is affected by the input signal), and the source voltage is the output signal, the level shift from input to output becomes a function of the input signal. Thus, this problem is inherent in the FET source-body structure and causes an attenuation of the output signal because V.sub.GS is proportional to the input signal, as shown in FIG. 1B (not drawn to scale). Ideally, the biasing means should compensate for the source-body voltage fluctuation and maintain V.sub.GS at a constant (DC) level without the variation seen in FIG. 1B.
Many analog circuits that use such conventional followers are differential circuits implemented to reject common-mode noise. In such a case the effect described above is doubled because the thresholds change in opposite directions. A typical differential source follower is illustrated in FIG. 1 and its transfer function shown in FIG. 2. Note the difference between the input signal voltage and the output signal voltage for signal magnitudes greater than about .+-.200 mV, which mismatch by about 5% in the .+-.500 mV range. For circuits that process the absolute amplitude of the input signal, such as peak detectors, this margin of error can be a significant drawback.
It is an object of the invention to provide a differential source follower with no body effect induced errors.
It is another object of the invention to provide an analog input buffer providing accurate performance over a wide range of input signal levels.
It is yet another object of the invention to provide a differential source follower with a low power mode.

Differential source follower with body effect compensation

International Business Machines Corporation


A multibeam hemispherical X-band array inserts nulls at horizontal and near horizontal angles to suppress interfering signals, without degrading authentic signals arriving at other angles. The multibeam hemispherical array includes three annular (360) rows of antenna elements, each row having 64 elements. Elements of the first row, which have the smallest elevation angle, have pairs of circular patches coupled with a phase delay line. Each pair of circular patches is spaced apart from and aligned with two pairs of similarly shaped (circular) and sized parasitic directors. The spacing between driven patches of adjacent elements in a row is about equal to one half of the wavelength of the radiated wave. The array fits within a conventional 24-inch diameter marine radome.

Multi-beam hemispherical arrays suitable for fleet command and control communications with secondary radar functionality are known. A nonlimiting example of such an array is disclosed in U.S. Pat. No. 10,965,039 (Chandler et al.). Charles McCarrick of Micro-Ant, LLC, first conceived and reduced to practice the antenna array described in Chandler et al. Without conveying any intellectual property rights, McCarrick disclosed the array to representatives of Lockheed Martin Corporation. Lockheed Martin Corporation then applied for patent protection on systems and methods that include Micro-Ant's array. The entire disclosure of Chandler et al. is incorporated herein and made a part hereof by this reference.
The array described by Chandler is susceptible to error, particularly from transmissions and receptions from elements at the bottom row of the array, i.e., the row nearest the base. Elements in the bottom row are oriented at the smallest elevation angle, i.e., the angle relative to vertical, or relative to a normal line extending from the base. Elements in the bottom row of the array in Chandler et al. are configured to transmit and receive signals at and near the azimuth, but not configured to mitigate interference from the horizon.
Transmitted and received signals are subject to degradation by several factors, including, inter alia, signal multipath which occurs when a signal reflects off of objects such as vehicles, buildings or other structures before reaching a receiver or target. A location of a mobile object, such as a drone, other aircraft, a missile and the like that is determined from a signal reflected off of ground-based objects will be erroneous. A transmitted signal reflected off of such objects may not reach an intended target.
A hemispherical array that is suitable for fleet command and control communications with secondary radar functionality, and mitigates interference from the horizon is needed. The invention is directed to overcoming one or more of the problems and solving one or more of the needs as set forth above.


A process reduced in mask steps for use in the fabrication of a thin film transistor having an LDD structure, comprising anodically oxidizing a gate electrode of a thin film transistor and performing ion implantation using the thus formed anodic oxide film as the mask. Also claimed is a similar process for fabricating a p-channel transistor and an n-channel transistor on a single substrate, comprising performing ion implantation of an impurity of the first conductive type to both of the transistor regions by using the anodic oxide film as a mask, and then performing ion implantation of an impurity of the second conductive type while masking one of the transistor regions with a resist.

1. Field of the Invention
The present invention relates to a liquid crystal electro-optical (display) device, and particularly, to a liquid crystal electro-optical (display) device (referred to simply hereinafter as "LCD") comprising a thin film transistor formed on a glass substrate.
2. Description of the Related Art
Liquid crystal display devices are widely used as display devices of the so-called lap-top (notebook) type apparatus, i.e., portable type information processing apparatus. Recently, attempts are also made to use the LCD as a high resolution color display device for the so-called desktop type apparatus, i.e., the stand-alone type information processing apparatus.
In achieving such a high resolution color display with an LCD, the so-called active matrix-addressed (active matrix) liquid crystal display device which drives each of the pixels by the individually provided thin film transistor (referred to simply hereinafter as a "TFT") is used. By employing the active-matrix type driving method, excellent display characteristics can be achieved by eliminating problematic cross talks which occur among the pixels in the simple matrix method. In the active-matrix type driving method, the TFTs are provided on one of the glass substrates constituting the liquid crystal panel so that each of the TFTs may control the applied voltage of the corresponding transparent pixel electrode.
In the LCD driven by the active matrix method, TFTs are formed on amorphous glass substrate. Accordingly, differing from an ordinary transistor formed on a single crystal Si substrate, an amorphous silicon or a polycrystalline silicon, i.e., a so-called polysilicon, is used for the active portion of channel layer and the like of the TFT. Although polysilicon is more favorable for a TFT than amorphous silicon because the mobility of carriers is higher for the former as compared with that for the latter, it contains structural defects such as grain boundaries at a density substantially higher than single crystal silicon. As a result, polysilicon TFTs tend to suffer high leak current.
To minimize the leak current, many TFTs for LCDs employ the so-called LDD (Lightly Doped Drain) structure. By utilizing the LDD structure, the concentration of impurities in the drain region can be slightly lowered at the portion neighboring the channel region, and by then applying an electric field to such a portion of lowered impurity concentration, the focusing of electric field to the channel region is relaxed.
FIGS. 10A to 10C are diagrams showing the process steps for fabricating a conventional polysilicon TFT.
Referring to FIG. 10A, polysilicon patterns 11A and 11B are formed on a glass substrate 10 in correspondence with an n-channel transistor and a p-channel transistor, and gate patterns 13A and 13B are formed on the polysilicon patterns 11A and 11B with gate oxide films 12A and 12B interposed respectively therebetween. In the step with reference to FIG. 10A, the region for forming a p-channel transistor Tr.sub.2 is protected by a resist 14B, and P.sup.+ ions are implanted by using the gate electrode 13A as the mask. As a result, a channel region 11c corresponding to the gate electrode 13A sections the polysilicon pattern 11A so as to provide n-type regions 11a and 11b to form the source and drain regions of an n-channel transistor Tr.sub.1.
Then referring to FIG. 10B, the resist 14B is removed, and another resist 14A is deposited in such a manner to cover the n-channel transistor Tr.sub.1 formed in the step with reference to FIG. 10A. Then, B.sup.+ ions are implanted into the resulting structure by using the gate electrode 13B as the mask. Thus, sectioned by a channel region lid just below the gate electrode 13B, p-type regions 11e and 11f are formed in the polysilicon pattern 11B.
After stripping off the resist 14A, heat treatment is applied to form a circuit comprising an n-channel transistor Tr.sub.1 and a p-channel transistor Tr.sub.2 on the glass substrate 10.
Conventionally, in case of forming the aforementioned LDD structure in an n-channel or a p-channel transistor above, for instance, a process with reference to FIG. 11A has been conventionally employed. More specifically, referring to FIG. 11A, an oxide film 15 is deposited on a previously formed transistor Tr.sub.1, and anisotropic etching is applied from the upper side by means of RIE to form oxide films 15a and 15b on the side walls of the gate electrode as is shown in FIG. 11B. Then, by further implanting ions using the gate electrode having thereon the oxide films as a mask to form the heavily doped regions 11a and 11b, LDD regions 11a' and 11b' can be formed between the channel region and the region 11 and between the channel region and the region 11b. The same process is conducted for the p-channel transistor Tr.sub.2. I n the conventional process for fabricating a TFT as described above with reference to FIGS. 10A and 10B, however, mask process must be performed twice. Moreover, the problem is that the mask used for implanting P.sup.+ ions in the process of FIG. 10A cannot be removed easily. Although ashing for a considerably long duration of time is necessary to remove the resist, such a treatment may impose negative effects on the characteristics of the TFT formed on the glass substrate by a low temperature fabrication.
Furthermore, in case of forming an LDD structure on the TFT, it is necessary to perform a process comprising depositing an oxide film 15, and after performing anisotropic etching by means of RIE, implanting ions using the resulting side wall oxide films 15a and 15b as masks. Such a complicated process has been found problematic. It is possible to form an LDD structure using other masks instead of the side wall oxide films, but at the expense of incorporating an additional mask process.

Process for fabricating liquid crystal electro-optical device comprising complementary thin film field effect transistors

Semiconductor Energy Labaratory Co., Ltd.


An optical particle counter generates a signal indicating an amount of radiation scattered by aerosols in a sample flow. Smoke can be discriminated from other aerosols in the sample flow by analyzing the AC component of the signal. Smoke has a much higher signal-to-noise ratio than that of larger particles such as dust and fog.

This invention relates in general to aerosol detection and in particular to apparatus and method of discriminating one type of aerosol from other types of aerosols in a sample flow.
Optical particle counters are well known for their ability to detect the presence of aerosols in sample flows. The optical particle counter (OPC) 2 of FIG. 1 analyzes a sample flow traversing a relatively small optical volume. A source 4 propagates a beam 6 of radiation into the sample flow. The radiation can be collimated or uncollimated. If the sample contains aerosols, such as dust, fog or smoke, the aerosols scatter the radiation from the beam 6. All aerosols scatter the radiation at an angle .theta.of 90.degree. from the beam propagation direction. Thus, a photodetector 8 at a 90.degree. angle generates a signal whose amplitude is proportional to the amount of scattered radiation.
The OPC analyzes the sample flow in near real-time. Micron and submicron particles can be sized without affecting the aerosol process. Laser-based OPCs can detect aerosols as small as 0.1 microns.
The OPC of FIG. 1 can be used in a clean room, where aerosols such as smoke and dust cannot be tolerated. Should these aerosols appear in the sample flow, alone or in combination, the OPC triggers an alarm.
However, the OPC cannot discriminate smoke from other aerosols contained in the sample flow. Therefore, the OPC has little utility as a smoke detector when the sample flow contains non-smoke aerosols such as dust. The dust would cause the OPC to trigger a false alarm.

Aerosol discriminator for particle discrimination


A vehicle communication access framework and a method are provided. The vehicle communication access framework comprises: a first device residing in a vehicle, a first processing system operated by a trusted third party, a second processing system operated by an original equipment manufacturer (OEM) of the vehicle, and a third processing system operated by a third party provider; wherein communication accesses among the first device, second processing system and third processing system are based on Identity Based Cryptography (IBC) private keys generated by the first processing system to respective first device, second processing system and third processing system.

As shown in FIG. 1, a future vehicle 110 is a connected car indulging in communication with several external entities such as other vehicles 111, automaker's cloud 120, mobile devices (e.g., smartphone, laptop, PDA etc.) belonging to vehicle owner 130, infrastructure 140, pedestrians 150 and third party clouds 160 forming vehicle-to-everything (V2X) communication 100. Several features are packaged in a connected car such as driver assistance, remote car control, Internet connectivity, external device connectivity, infotainment etc., with the participation of above entities. Most of the car communication is a two-way wireless communication using either short range or long range communication medium. Currently, several communication technologies have become an integral part of modern cars such as long range GPS, GSM, 3G, 4G etc., and short range Wi-Fi, Bluetooth, RFID, NFC, DSRC, etc.
Communication between vehicle, automaker's cloud and mobile devices is usually operation-related communication which takes place to perform operations such as to take control of or obtain information from the car. The mobile device could be in direct communication range of the vehicle using any short range communication medium or it can remotely contact the vehicle via a service provided by automaker's cloud using a long range communication medium. Communication between vehicle and all other entities constitutes service-related communication to implement services such as road safety, on-the-road-information, value added services and infotainment.
The connected cars' data is private and confidential and should not be accessible to the outside world. Security is a major concern in car communication since wireless communication opens the door for several remote attacks. Any wireless-enabled device eavesdropping on the broadcast wireless communication as well as pretending to be a legitimate entity can add spoofed communication. Strong Authentication and Confidentiality mechanisms are required to thwart identity spoofing attack and eavesdropping attack respectively. Authentication can be implemented via Message Authentication Code (MAC) using symmetric key based cryptography or via secure signature schemes using Public Key Cryptography (PKC). Eavesdropping on the other hand can be avoided by implementing Encryption schemes.
Existing approaches either use symmetric key based or traditional certificate based PKC based solutions. They both have their own problems when utilized in V2X communication.
In symmetric key cryptography, both communicating parties share a copy of the same private key. A single private key is used on both sides to compute and verify a MAC for authentication or to encrypt/decrypt data for confidentiality. Symmetric key system suffers from the problems of 1) how to securely distribute private shared key to each entity involved in communication, and 2) compromise/misuse of the private key by an intruder where several entities have a copy of the same key. Symmetric key based solutions do not suit V2X environment where a large number of random entities are involved in communication needing same private key. Furthermore, trusting each entity in such a heterogeneous environment is not practical. Hence, symmetric key is not a suitable solution for V2X communication.
In traditional certificate based PKC system, a related pair of keys is generated for a user. User keeps one key for private use and makes other key public. Private key can then be used either to decrypt a document that has been encrypted using the corresponding public key, or to sign a message which can be verified with the corresponding public key. The public key is bounded to the user by mean of a certificate obtained from CA (certification authority), a TTP (trusted third party), who ensures the correct key is bound to the certificate and signs the certificate using its own private key to ensure the authenticity of the certificate's contents. The PKI (Public Key Infrastructure) is the infrastructure that handles the management of keys and certificates (distribution and identification of public keys and certificates).
Traditional certificate based PKC based solutions suffer from the problem of complex PKI system. One must have other entities certificate to establish a secure channel. Moreover, they are time and resource consuming requiring at least one signature verification to verify the signed certificate before the public key can be used for authentication or decryption. Hence, PKI should be avoided wherever possible.
Real time services of vehicles such as collision avoidance system, traffic management system etc., need speedy security. Certificate verification time may be crucial for time critical collision avoidance system. Signature generation and verification should also be efficient in terms of time consumption in order to avoid fatal accidents. Moreover, managing digital certificates and their associated keys is complex in dynamic communication network of connected cars.
Hence, those skilled in the art are striving to provide a method of establishing communication between the vehicle and other systems in a quick and efficient manner.

Securing outside-vehicle communication using IBC


A powered toothbrush includes a handle having a neck. A head is mounted to the neck and has a first surface and an opposed second surface. A first tuft block is mounted to the head, with the tuft block having tooth cleaning elements extending outwardly from the first surface. A tissue cleanser is mounted to the head and has a plurality of tissue engaging elements extending outwardly from the second surface. A drive assembly configured to cause the first tuft block and the tissue cleanser to move with respect to the head.

As toothbrush design has evolved in an effort to improve cleaning of teeth and gums, the complexity of toothbrushes and their functions have increased. Powered toothbrushes are one example of efforts to improve tooth cleaning by including one or more movable sets of cleaning elements.
According to the American Dental Association, a major source of bad breath in healthy people is microbial deposits on the tongue, where a bacterial coating harbors organisms and debris that contribute to bad breath. The tongue is a haven for the growth of microorganisms since the papillary nature of the tongue surface creates a unique ecological site that provides an extremely large surface area, favoring the accumulation of oral bacteria. Anaerobic flora and bacteria residing on the tongue play an important role in the development of chronic bad breath commonly called halitosis. In general, the bacteria produce volatile sulfur compounds (VSC). If there is enough buildup of the sulfur compounds, the result can be lead bad breath or oral malodor.
Consequently, tissue cleansers have been added to a face of the head of a conventional toothbrush opposite the face on which the tooth cleaning elements are positioned.
It would be desirable to provide a powered toothbrush with a tooth cleanser that reduces or overcomes some or all of the difficulties inherent in prior known devices. Particular objects and advantages will be apparent to those skilled in the art, that is, those who are knowledgeable or experienced in this field of technology, in view of the following disclosure of the invention and detailed description of certain embodiments.

Powered toothbrush with two-sided moving head


A planar epitaxial film of tin oxide has low defect density, high purity, crystalline rutile unit cell structure, one crystalline orientation, controlled stoichiometry, extended lateral dimensions, extremely smooth surface morphology, a high degree of atomic order extending to the surface of the film and is colorless and transparent. The film is made by a method which includes reactive sputter deposition. The films can be used in chemical sensors as well as in numerous other applications.

A number of methods have been reported for producing tin oxide and related oxide materials. Powders have been produced and studied for a number of years. For certain applications, however, the advantages of films have made film deposition the fabrication method of choice.
The richness of the chemical, electronic and mechanical properties of oxide films has made them useful in a wide variety of applications. The majority of the technological films currently available are polycrystalline. Polycrystalline films result from processes which do not rigorously control the microstructure of the film during deposition. These films are textured and have distributions of varying crystalline structures, sizes, and orientation and a large number of grain boundaries. Additionally, while polycrystalline films of oxide having extended lateral dimension (>1 cm.sup.2) have been obtained, highly ordered oxides have been generally limited to single crystals, the dimensions of which for many oxides are are typically less than about 1 cm.sup.2.
Nagano in "Chemical Vapor Deposition of Tin Oxide Thin Films on Rutile Single Crystals", J. Crystal Growth, 67, 639-644 (1989), teaches the deposition of thin films of tin oxide on the surface of titanium oxide by chemical vapor deposition. Kane, et al., in "Chemical Vapor Deposition of Antimony Doped Tin Oxide Film Formed from Dibutyl Tin Diacetate", J. Electrochem. Soc.: Solid State Science and Technology, volume 123, Number 2, February, 1976, teaches a chemical vapor deposition process for preparing transparent conducting layers of antimony doped tin oxide utilizing dibutyl tin diacetate, antimony pentachloride, oxygen, water and nitrogen as a carrier gas at a substrate temperature of 400.degree. to 550.degree. C. This method was designed to fulfill a need for more highly conducting coatings than those obtainable without doping, while still possessing optical transmission in excess of 80% throughout the visible spectrum.
In "Growth of Highly Oriented Tin Oxide Thin Films by Laser Evaporation Deposition", Appl. Phys. Lett., 57, 29 Oct. 1990, Dai et al. disclose conducting thin films of tin oxides which were prepared by the laser evaporation of a pressed polycrystalline undoped powder tin oxide onto unheated substrates. Kuriki et al. in "Gas sensing Characteristics of Reactively Sputtered SnO.sub.2 Films", Electronics and Communications in Japan, Part 2, Vol. 70, No. 4, 1987, disclose gas sensors which are composed of polycrystalline SnO.sub.2 films. In many cases imperfections in these oxides such as grain boundaries, surface steps, and oxygen vacancy defects set limits on the functionality of the film.
Nearly perfect (pure), stoichiometric, structurally ordered in both short and long range, smooth, crystal-like tin oxide films formed by heteroepitaxial growth would be expected to exhibit more uniform properties and interactions when presented to technological environments and stimuli, as for example gases, photons, and electrons. With only one crystalline orientation throughout and no defect sites the adsorption kinetics would be coherent across the film. Removing structural defects (large ones such as grain boundaries, or small ones such as individual vacancy sites), would produce a much more uniform optical density by removing random scattering sites for transparent conductors. Near perfection in such films could also be expected to yield higher mobilities in electronic transport and when the perfection extends out to the surface, it could allow unique control of frictional coefficients.
While the advantages of producing high quality completely epitaxial films of non-oxide materials has been widely recognized in the semiconductor industry, efforts to produce films at equivalent quality for oxide materials have largely been confined to research on the high temperature superconductor materials.
Chang et al. in "Ceramic Epitaxial Films and Multilayers Prepared by MOCVD", Proceedings of the 7th CIMTEC World Ceramics Congress, Montecatini Terme, Italy, Jun. 24-30, 1988 and in "Epitaxy of TiO.sub.2 Thin Film on Sapphire by MOCVD", MRS Spring Meeting Symposium J, "Thin Film Structures and Phase Stability", San Francisco, Calif. Apr. 16-21, 1990, report the production of epitaxial titanium oxide films using MOCVD. In "Epitaxy of TiO.sub.2 Thin Film on Sapphire by MOCVD" supra, the growth of epitaxial titanium oxide films on sapphire substrates by thermally decomposing titanium isopropoxide in the presence of oxygen in a cold wall low pressure MOCVD system is disclosed. In "Ceramic Epitaxial Films and Multilayers Prepared by MOCVD", supra, epitaxial titanium oxide and vanadium oxide films on sapphire substrates are produced using the MOCVD process for growth of the films in single and multilayer configurations. Titanium oxide and aluminum oxide films were deposited using molecular beam epitaxial methods in "Titanium Oxide Aluminum Oxide Multilayers Ceramic Thin Films", Alexander et al., J.Am. Ceram. Soc., vol. 73( 6), 1990. In "Epitaxial Thin Films of ZnO on Cds and Sapphire", J. Vacuum Sci. and Tech., vol. 6, no. 1, 1968, Rozgonyi et al., discuss epitaxial films of ZnO, a non-rutile structured oxide, produced by sputtering on sapphire. Shiosaki et al, in "High Rate Epitaxial Growth of ZnO Films on Sapphire by Planar Magnetron Sputtering System", J. Crystal Growth, 45 (1978) 346-349 production of epitaxial films of ZnO were obtained on sapphire.
Additionally, the development of chemical sensors based on thin film technology is a rapidly growing area in chemical sensing. Thin film sensors offer the potential advantages of lower cost, greater sensitivity, less drift, and the achievement of selectivity by integrating different sensors on a single wafer for using semi-conductor microfabrication techniques. Key to development of such a technology is an understanding of what film characteristics are important for sensing and how to optimize processing to enhance those characteristics.

The United States of America, as represented by the Secretary of Commerce


A herbicidal composition comprising a herbicidally acceptable carrier and/or surface active agent and, as active ingredient, a synergistically effective amount of. (1) at least one 2,6-disubstituted pyridine of formula I ##STR1## in which x independently represents a halogen atom or a haloalkyl group; and. n is an integer of 1, 2 or 3; and. (2) at least one additional herbicidal compound, which is active against broad-leaved weeds and/or annual grasses;. which provides a synergistic effect against a broad spectrum of weed species, e.g., in cereal crops, and a method for controlling weeds by applying a synergistically effective amount of a compound (1) and a compound (2) to a locus.

The present invention relates to an improvement in the efficacy of herbicidal 2,6-substituted pyridines by combination with a selected second herbicidal compound.
The herbicidal 2,6-disubstituted pyridines to be used according to the present invention are a group of compounds, disclosed in International Application WO 94/22833, which display excellent herbicidal performance, in particular against broad-leaved weeds in cereal crops. However, the 2,6-disubstituted pyridines, when used as the sole active ingredient, do not always achieve effective control of the full spectrum of weed species encountered in commercial agronomic applications, in conjunction with reliable selectivity for the crop species. Such gaps in the spectrum of control can be overcome by co-treatment with another herbicide known to be effective against the relevant weed species. The combined use of herbicidal pyridines and other herbicides has been described in International Patent Application WO 94/07368.
Surprisingly, it has now been found, that the combined herbicidal activity of certain 2,6-disubstituted pyridines with various other herbicides against many broad-leaved weeds and annual grasses is much greater than expected when applied pre- or post-emergence and that this activity cannot be ascribed to an additive effect, but to a remarkable degree of synergism on many broad-leaved weed species and annual grasses, for example on Setaria viridis, Alopecurus myosuroides, Poa annua, Stellaria media, Lamium purpureum, Galium aparine, Veronica hederaefolia, Papaver rhoeas or Matricaria inodora. These combinations show a much higher level of activity than predicted from that of the individual compounds, which also enables a greater selectivity for the crop species.
A mixture of herbicides shows synergistic effect if the herbicidal activity of the mixture is larger than the sum of activities of the separately applied compounds. The expected herbicidal activity for a given mixture of two herbicides can be calculated as follows (See Colby, S. R., "Calculating synergistic and antagonistic response of herbicide combinations", Weeds 15, pp 20-22 (1967): ##EQU1## wherein
X is the percentage of growth inhibition upon treatment with a herbicide 1 at a dose of p kg/ha compared with an untreated control (X=0%)
Y is the percentage of growth inhibition treatment with a herbicide 2 at a dose of q kg/ha compared with an untreated control
WE is the herbicidal effect to be expected upon treatment (% of growth inhibition compared with untreated control) with a combination of herbicide 1 and 2 at a dose of p+q g/ha, respectively.
If the actual weed control (W) exceeds the expected (calculated) eed control (WE), the mixture displays a synergistic effect.


In one embodiment, a semiconductor manufacturing apparatus includes an accommodation module configured to accommodate a substrate. The apparatus further includes a first flow channel including first openings configured to emit a first gas into the accommodation module. The apparatus further includes a second flow channel including second openings configured to emit the first gas into the accommodation module, a number or a size of the second openings being different from a number or a size of the first openings. The apparatus further includes a controller configured to control supplying of the first gas to the first and second flow channels such that the first gas is emitted from the first openings at a first flow velocity and the first gas is emitted from the second openings at a second flow velocity different from the first flow velocity.

Atomic layer deposition (ALD) is a film forming method having an excellent property for controlling a thickness of a thin film. However, when the ALD is applied to a batch-type film forming apparatus that simultaneously forms films on plural wafers, an amount of a source gas arriving at a center portion of a wafer becomes smaller than an amount of the source gas arriving at a circumferential portion of the wafer if a surface area of a base layer, which is a film forming target on the wafer, becomes larger. As a result, the thickness of the film on each wafer becomes different in the circumferential portion and the center portion, so that in-plane uniformity of the thickness of the film is deteriorated. However, if a gas supply amount or a wafer interval is simply adjusted to improve the in-plane uniformity of the thickness of the film, quality of the film may be deteriorated and a film forming process may be complicated.

Semiconductor manufacturing apparatus and semiconductor manufacturing method


The invention relates to modified neomycin phosphotransferase genes and their use in a selection method for high-producing recombinant cells. The invention further relates to expression vectors which contain a modified neomycin phosphotransferase gene and a gene of interest functionally linked to a heterologous promoter and a method of preparing heterologous gene products using these expression vectors.

The invention relates to new modified neomycin-phosphotransferase genes and their use in selection methods for high-producing recombinant cells. Accordingly, the present invention also relates to new expression vectors which contain a modified neomycin-phosphotransferase gene, preferably combined with a gene of interest functionally linked to a heterologous promoter. The invention further relates to methods of preparing heterologous gene products using the corresponding high-producing recombinant cells.
Mammalian cells are the preferred host cells for the production of complex biopharmaceutical proteins as the modifications carried out post-translationally are compatible with humans both functionally and pharmacokinetically. The main relevant cell types are hybridoma, myeloma CHO (Chinese Hamster Ovary) cells and BHK (Baby Hamster Kidney) cells. The cultivation of the host cells is increasingly carried out under serum- and protein-free production conditions. The reasons for these are the concomitant cost reduction, the reduced interference in the purification of the recombinant protein and the reduction in the potential for the introduction of pathogens (e.g. prions and viruses). The use of CHO cells as host cells is becoming more widespread as these cells adapt to suspension growth in serum- and protein-free medium and are also regarded and accepted as safe production cells by the regulatory authorities.
In order to produce a stable mammalian cell line which expresses a heterologous gene of interest (GOI), the heterologous gene is generally inserted in the desired cell line together with a selectable marker gene such as e.g. neomycin phosphotransferase (NPT) by transfection. The heterologous gene and the selectable marker gene can be expressed in a host cell starting from one individual or separate co-transfected vectors. Two to three days after transfection the transfected cells are transferred into medium containing a selective agent, e.g. G418 when using neomycin phosphotransferase-gene (NPT gene), and cultivated for some weeks under these selective conditions. The emerging resistance cells which have integrated the exogenous DNA can be isolated and investigated for expression of the desired gene product (of the GOI).
A major problem in establishing cell lines with a high expression of the desired proteins arises from the random and undirected integration of the recombinant vector into transcriptionally-active or transcriptionally-inactive loci in the host cell genome. As a result a population of cells is obtained which have completely different expression rates of the heterologous gene, the productivity of the cells generally following normal distribution. In order to identify cell clones which have a very high expression of the heterologous gene of interest it is therefore necessary to examine and test a large number of clones, which is time consuming, labour intensive and expensive. Improvements to the vector system used for transfection therefore set out to increase the proportion of high producers in the transfected cell population by suitable selection strategies and thereby reduce the expenditure and work involved in clone identification. The development of such an expression system is the subject of the present invention.
The amino glycoside-3′-phosphotransferase II enzyme (neomycin-phosphotransferase) (EC27195) the gene of which is transposon 5-associated in Escherichia coli is used as a selectable marker in a number of organisms (e.g. bacteria, yeasts, plants and mammalian cells). This enzyme confers resistance to various aminoglycoside antibiotics such as neomycin, kanamycin and G418, by inactivating the antibiotics by transferring the terminal phosphate from ATP to the 3′ hydroxyl group of the aminohexose ring I. In addition to the wild-type neomycin phosphotransferase some mutants are known which have reduced phosphotransferase activity and hence reduced resistance to aminoglycoside antibiotics in bacteria (Blázques, J. et al., Molecular Microbiology 1991, 5(6), 1511-1518; Kocabiyik, S. et al., Biochem Biophys Res Commun 1992, 185(3), 925-931; Yenofsky, R. L. et al., Proc Natl Acad Sci USA 1990, 87, 3435-3439) and in slices of leaf from tobacco (Yenofsky, R. L. et al., Proc Natl Acad Sci USA 1990, 87, 3435-3439).
One of these mutants (Glu182Asp) was used as a marker for selecting embryonic stem cells, the neomycin phosphotransferase gene being integrated into the c-myc gene by targeted homologous recombination (gene targeting) (Hanson, K. D. et al., Mol Cell Biol 1995, 15(1), 45-51). The authors restrict themselves to the use of the modified enzyme for gene targeting.
Patent application WO 99/53046 describes the expression of a modified neomycin phosphotransferase gene (Asp261Asn) in production-relevant mammalian cells. The authors describe a non-cloning method for expression of a gene of interest in mammalian cells. By cotransfection of the cells with three individual DNA fragments which code for a promoter element, a gene of interest and a selectable marker coupled with an IRES ("Internal ribosomal entry site") element, it is possible to deliberately grow cells, under selection pressure, in which all three DNA fragments are combined as a functional bicistronic transcription unit (promoter gene of interest-IRES-neomycin-phosphotransferase gene). The arrangement of the elements only occurs in the transfected cell, so that only a few cells show the correct arrangement of the elements. Moreover, after gene amplification, using an amplifiable selectable marker, no high producing clones can be generated. After repeated selection and gene amplification the cells generated exhibited at most 6 pg of protein per cell per day (6 pg/cell/day).
None of the publications discloses modified neomycin phosphotransferase genes with particular suitability for the preparation of a high expression vector system for mammalian cells which makes it possible to develop high producing cells in order to prepare recombinant biopharmaceutical proteins which contain one or more complete functional transcription units both for one or more genes of interest and also for a modified neomycin phosphotransferase gene with reduced antibiotic resistance. The DNA construct described in WO 99/53046 contains only a promoter-less neomycin gene functionally linked to the gene for dihydrofolate reductase (DHFR).
There is therefore a need to make suitable modified neomycin phosphotransferase genes available, particularly for the development of corresponding high expression vector systems for biopharmaceutical processes. The problem of the present invention was therefore to provide corresponding new modified neomycin phosphotransferase genes, expression vectors which contain a modified neomycin phosphotransferase gene and a gene of interest functionally linked to a heterologous promoter, a method of selection for high producing recombinant cells, preferably for mammalian cells, and a process for producing heterologous gene products.
Surprisingly, within the scope of the present invention, it has been possible to produce and identify new modified highly selective neomycin phosphotransferase genes which are characterised by their particular suitability for the selection of high producing cells.

Neomycin-phosphotransferase-genes and methods for the selection of recombinant cells producing high levels of a desired gene product

Boehringer Ingelheim Pharma GmbH & Co. KG


An inner tie rod tool includes a hollow tube which fits over the rod and includes a socket at one end for cooperation with a socket tool. The opposite end includes a retainer which is cooperative with C-shaped wrench discs of various size and configuration that cooperate with the nut associated with the inner end of the inner tie rod.

This invention relates to an improved inner tie rod tool and, more particularly, to an inner tie rod tool which is useful in the removal and replacement of various types of automobile inner tie rods.
American and foreign automobiles are often equipped with a rack and pinion steering control system. Such a rack and pinion system indudes a rack which is connected by means of tie rods to the front wheels of the vehicle. Rotation of the steering wheel rotates the pinion to drive the rack and simultaneously move the tie rods to effect steering by the front wheels.
Servicing and repair of such a rack and pinion steering control system often requires removal and replacement of the tie rods (including the inner tie rods) which connect the rack to the front wheels. The inner tie rods of a rack and pinion system may typically be comprised of a rod with a hexagonal nut located at the inner end and with threads at the outer end. The hexagonal nut is provided for cooperation with a wrench so that the rod can be rotated for attachment to rack assembly. The outer threaded end cooperates with a linkage attached to the front wheel of the automobile.
Alternatively, the inner tie rods may have a different construction. For example, the hexagonal nut at the inner end may be eliminated or altered in construction. This has resulted in increased difficulty in servicing the steering system, in many instances, resulting in the need to remove the entire rack and pinion system in order to effect appropriate repair and replacement of inner tie rods. The present invention is directed to a mechanism which permits the removal of inner tie rods without requiring the disassembly of the entire rack and pinion steering control assembly, and which is useful with multiple types of inner tie rods.


A valve has a valve body with first and second intake passages, first and second supply passages and a reservoir return passage defined therein. A shuttle member is movable within the valve body between a first flow position and a second flow position. In the first flow position, the shuttle member defines a first fluid flow path between the first intake passage and the first supply passage and a second fluid flow path between the second supply passage and the reservoir return passage. In the second flow position, the shuttle member defines a third fluid flow path between the second intake passage and the second supply passage and a fourth fluid flow path between the first supply passage and the reservoir return passage. The valve is useful in a bi-directional hydraulic power system having at least one hydraulic component, a reservoir for hydraulic fluid, and a bi-directional pump.

A bi-directional hydraulic power system may comprise a reservoir, a bi-directional pump, at least one hydraulic component that receives and returns hydraulic fluid, and a plurality of fluid lines connecting these components in fluid communication with one another. By driving the bi-directional pump to rotate in a first direction, hydraulic fluid is moved into a first part of the hydraulic component to apply hydraulic pressure thereto, thereby causing the hydraulic component to perform a movement. This forces hydraulic fluid to be expelled from a second part of the hydraulic component to circulate within the hydraulic power system. Similarly, driving the pump in the opposite direction will move hydraulic fluid into the second part of the hydraulic component, causing the component to move in the opposite manner and to expel fluid from its first part into the hydraulic power system.
In most bi-directional hydraulic power units, hydraulic fluid flow returning to the system from the hydraulic component or components is passed directly to one of the pump inlets. If air is entrained in the return flow of hydraulic fluid, the air will be passed back into the pump and will not be vented to the atmosphere from the hydraulic system. Air in the hydraulic system causes several problems, including jerky movement of components, "spongy" components, air lock of pilot operated check valves, as well as noisy pumps and valves.
Previous attempts to obviate this problem have included pre-filling the hoses to be used in the hydraulic system, and bleeding air from the hydraulic system. Pre-filling hoses and bleeding air often results in spillage of hydraulic oil which can be an environmental hazard if not contained properly. In addition, a user must generally bleed the air from the highest points in the hydraulic power system, which points are not always accessible once the system has been installed in the application. Furthermore, both of these methods are manual and time consuming.
Another method that has been used in the prior art is to install air vent cartridge valves in the hydraulic system. However, such air vent cartridge valves must be external to the power unit and require additional connections. Furthermore, such an approach requires two valves, one each side of the hydraulic component, which adds additional cost to the system. Moreover, air vent cartridge valves are meant to work on the high-pressure side of the system, not on the low-pressure return side, and therefore will not allow air to be purged from the return flow of hydraulic fluid. Thus, hydraulic fluid having air entrained therein will still be passed back to the inlet of the pump, and pump and valve noise, as well as possible air lock of pilot operated check valves, remains a problem

Shuttle valve for bi-rotational power units


A suction passage (1) and a discharge passage (2) for a to-be-transferred fluid are disposed in a pump body (3). A bottomed cylindrical bellows (6) is integrally coupled to the axial rear side of the pump body to form a closed space (7). The suction passage (1) has an upstream portion (1A) having a larger diameter and a predetermined passage cross section area, and downstream portions (1B) which are formed by branching the upstream portion into a bifurcated or Y-shape while reducing the passage cross section area. Two first small check valves (15) of the spring type in each of which the pressure receiving area is reduced in accordance with the reduced passage cross section areas of the smaller-diameter downstream portions (1B) are attached respectively to outlet portions of the smaller-diameter down-stream portions (1B) so as to be arranged in parallel. The outlets of the first check valves (15) are opened in the closed space (7).

1. Field of the Invention
The present invention relates to a reciprocating pump which is useful for quantitative transfer of chemical liquids or ultrapure water to be used in processes such as washing of surfaces of ICs or liquid crystal display devices in a semiconductor producing apparatus.
2. Explanation of Related Art
Conventionally, a double-bellows reciprocating pump is known which is useful for quantitative transfer of chemical liquids or ultrapure water to be used in processes such as washing of surfaces of ICs or liquid crystal display devices in a semiconductor producing apparatus (for example, see Japanese Patent Application Laying-Open No. 11-324926).
As shown in FIG. 14, the reciprocating pump has: a pump body 3 in which a suction passage 1 and a discharge passage 2 for a to-be-transferred fluid are disposed; and a bottomed cylindrical pump casing 4 which is integrally coupled to an axial rear end side of the pump body 3. A front end opening peripheral portion 6A of a bottomed cylindrical bellows 6 is air-tightly (liquid-tightly) fixed by an annular pressing plate 5 which is made of FRP, and which is clamped and fixed between a rear end peripheral portion of the pump body 3 and the front end face of the pump casing 4, thereby forming a closed space 7 defined by the pump body 3 and the bellows 6. A fixing plate 8 made of stainless steel is integrally coupled by plural bolts 8A to the rear side of a rear end closing portion 6B of the bellows 6. A tip end portion of a piston rod 9 which rearward elongates in the axial direction is interposed between the fixing plate 8 and the rear end closing portion 6B of the bellows 6. The stainless steel piston rod 9 is integrally coupled to the bellows 6.
A rear end portion of the piston rod 9 is air-tightly passed through a rear end closing portion 4A of the pump casing 4 so as to be advanceable and retractable in the axial direction, and is exposed in a cylinder 10 which is continuous to the rear side of the rear end closing portion 4A. A piston 11 which is to be axially advanced and retracted in the cylinder 10 is secured to the exposed portion. The cylinder 10 and the piston 11 constitute a reciprocal movement portion 12 for extendingly and contractingly deforming the bellows 6 by axial advancing and retracting movements in which the rear end closing portion 6B of the bellows 6 is advanced to the front dead center in the vicinity of the pump body 3, thereby decreasing the capacity of the closed space 7, and the rear end closing portion 6B of the bellows 6 is retracted to the rear dead center remote from the pump body 3, thereby increasing the capacity of the closed space 7. A proximity sensor sensing plate 13 which radially outward extends through an axial cutaway portion 10A formed in a part of the cylinder 10 is secured to the rear end face of the piston 11. Proximity sensors 14A, 14B are placed on the front and rear sides of the proximity sensor sensing plate 13, respectively.
By contrast, a first check valve 15 of the spring type which communicates with the suction passage 1 and allows only a flow in a suction direction to be conducted, and a second check valve 16 of the spring type which communicates with the discharge passage 2 and allows only a flow in a discharge direction to be conducted are attached in a parallel manner to the pump body 3. The outlet of the first check valve 15 and the inlet of the second check valve 16 are opened in the closed space 7.
The outlet of a to-be-transferred fluid suction pipe 18 which is formed by a fluororesin tube is connected through a pipe joint 17 to the inlet of the suction passage 1, and the inlet of a to-be-transferred fluid discharge pipe 19 which is formed by a fluororesin tube is connected via another pipe joint 17 to the outlet of the discharge passage 2. Each of the pipe joints 17 comprises: a nipple 17A having an external thread portion in one end to be screwed to the inlet of the suction passage 1 and the outlet of the discharge passage 2; an inner ring (not shown); and a cap nut-like pressing ring 17C. A valve V1 is connected in the to-be-transferred fluid suction pipe 18. The inlet of the to-be-transferred fluid suction pipe 18 is connected to a liquid tank 20 which stores a to-be-transferred fluid such as cleaning liquid.
The reciprocal movement portion 12 is reciprocally moved by a reciprocal driving device 21. The reciprocal driving device 21 comprises a compressed air supply source 22 consisting of a compressor, an electromagnetic 5-port 3-position directional control valve 23, and a controller 24. The compressed air supply source 22 and a primary port P of the directional control valve 23 are connected to each other through a compressed air supply pipe 25 in which a valve V2 is disposed. A secondary port A of the directional control valve 23 is connected through an air supply and discharge pipe 26 to an air supply and discharge hole 27 formed in the pump casing 4, and a secondary port B is connected through an air supply and discharge pipe 28 to an air supply and discharge hole 29 formed in the cylinder 10.
The controller 24 receives a proximity detection signal from the proximity sensor 14A or 14B which detects the proximity of the proximity sensor sensing plate 13, and outputs a switch signal to the directional control valve 23 on the basis of the proximity signal. When a push button (not shown) disposed on the controller 24 is manually operated, the directional control valve 23 is switched to a neutral position 23C to stop the operation of the reciprocal driving device 21, thereby stopping the operation of the reciprocating pump, or the valve is switched from the neutral position 23C to a first position 23A or a second position 23B to cause the reciprocal driving device 21 to operate, thereby starting the operation of the diaphragm reciprocating pump. In the figure, 30 denotes a cylinder cover which closes a rear end opening of the cylinder 10.
By contrast, a bottomed cylindrical accumulator casing 34 is integrally coupled to an axial front side of the pump body 3. A rear end opening peripheral portion 36A of a bottomed cylindrical accumulator bellows 36 is air-tightly (liquid-tightly) fixed by an annular pressing plate 35 which is made of FRP, and which is clamped and fixed between a front end peripheral portion of the pump body 3 and the rear end face of the accumulator casing 34, thereby forming a closed space 37 defined by the pump body 3 and the accumulator bellows 36. In this example, a pulsation suppression device 38 is integrally disposed on the front side of a front end closed portion 36B of the accumulator bellows 36. The inlet of the discharge passage 2 is opened in the closed space 37, and the closed space 7 communicates with the closed space 37 through the second check valve 16 and a through hole 39.
In the thus configured diaphragm reciprocating pump, the pump body 3, the pump casing 4, the bellows 6, the first check valve 15, the second check valve 16, the accumulator bellows 36, and like components are molded of a fluorine synthetic resin material such as PTFE or PFA which has excellent corrosion and heat resistance.
Next, the operation of the thus configured diaphragm reciprocating pump will be described. As shown in FIG. 14, when, in a pump stop state where the rear end closing portion 6B of the bellows 6 is at the front dead center DP1 in the vicinity of the pump body 3 to decrease the capacity of the closed space 7 and the directional control valve 23 is held to the neutral position 23C, the directional control valve 23 is switched to the second position 23B by manually operating the push button disposed in the controller 24, the compressed air supplied from the compressed air supply source 22 flows into the cylinder 10 via the route of the compressed air supply pipe 25→the primary port P of the directional control valve 23→the secondary port B→the air supply and discharge pipe 28→the air supply and discharge hole 29. Moreover, the compressed air which is in the pump casing 4, and which urges the rear end closing portion 6B of the bellows 6 toward the front dead center DPI via the fixing plate 8 is discharged to the atmosphere via the route of the air supply and discharge hole 27→the air supply and discharge pipe 26→the secondary port A→a primary discharge port R1. Therefore, the piston 11 is retracted to the end position in the cylinder 10, and, in accordance with the retraction, the rear end closing portion 6B of the bellows 6 is retracted to the rear dead center DP2 remote from the pump body 3, thereby increasing the capacity of the closed space 7.
In accordance with the increase of the capacity of the closed space 7, the negative pressure of the closed space 7 is gradually raised, and hence the to-be-transferred fluid stored in the liquid tank 20 is sucked into the closed space 7 via the route of the to-be-transferred fluid suction pipe 18→the suction passage 1→the first check valve 15. Namely, the suction pressure of the to-be-transferred fluid which is sucked from the to-be-transferred fluid suction pipe 18 into the suction passage 1 overcomes the spring force of a spring 15A of the first check valve 15 to expand the first check valve 15 (specifically, retract a valve element 15B of the first check valve 15), and the fluid is then sucked into the closed space 7.
When the suction stroke in which the piston 11 is retracted to the end position and the rear end closing portion 6B of the bellows 6 is retracted to the rear dead center DP2 is ended, the valve element 15B of the first check valve 15 begins to be closed by the spring force of the spring 15A. At the same time, the proximity sensor sensing plate 13 attached to the piston 11 approaches the proximity sensor 14B to be detected thereby, and the proximity detection signal is supplied to the controller 24. The controller 24 outputs the switch signal to the directional control valve 23 on the basis of the proximity detection signal supplied from the proximity sensor 14B, so that the directional control valve 23 is switched to the first position 23A. As a result, the compressed air supplied from the compressed air supply source 22 flows into the pump casing 4 via the route of the compressed air supply pipe 25→the primary port P of the directional control valve 23→the secondary port A→the air supply and discharge pipe 26→the air supply and discharge hole 27. Moreover, the compressed air in the cylinder 10 is discharged to the atmosphere via the route of the air supply and discharge hole 29→the air supply and discharge pipe 28→the secondary port B→a primary discharge port R2. Therefore, the rear end closing portion 6B of the bellows 6 is advanced to the front dead center DP1 via the fixing plate 8, whereby the capacity of the closed space 7 is decreased and the piston 11 is advanced to the starting position in the cylinder 10.
When the capacity of the closed space 7 is decreased, the to-be-transferred fluid inside the closed space 7 overcomes the spring force of a spring 16A of the second check valve 16 to expand the second check valve 16 (specifically, retract a valve element 16B of the second check valve 16), and is then discharged into the closed space 37 via the through hole 39 to be temporarily stored therein. Thereafter, the fluid is discharged into the to-be-transferred fluid discharge pipe 19 via the discharge passage 2. At this time, extending and contracting deformation of the accumulator bellows 36 is restricted within a constant range by the pulsation suppression device 38, so that the pulsation amplitude can be suppressed to a low level.
At the timing when the discharge stroke in which the piston 11 is advanced to the start position and the rear end closing portion 6B of the bellows 6 is advanced to the front dead center DP1 is ended, the second check valve 16 is closed. At the same time, the proximity sensor sensing plate 13 attached to the piston 11 approaches the proximity sensor 14A to be detected thereby, and the proximity detection signal is supplied to the controller 24. The controller 24 outputs the switch signal to the directional control valve 23 on the basis of the proximity detection signal supplied from the proximity sensor 14A, so that the directional control valve 23 is switched to the second position 23B. Thereafter, the above-mentioned operation is repeated so that quantitative transfer of the to-be-transferred fluid can be conducted in an intermittent manner, until when the directional control valve 23 is switched to the neutral position 23C by manually operating the push button disposed in the controller 24.
In a reciprocating pump of this kind, in the case where the suction stroke is switched to the discharged stroke, the inertia force of the to-be-transferred fluid in the suction passage 1, i.e., the inertia force of the to-be-transferred fluid which, in the suction stroke that is conducted immediately before the switch to the discharged stroke, flows through the suction passage 1 toward the first check valve 15 is applied as a load on the valve element 15B of the single first check valve 15. In the conventional reciprocating pump, the single first check valve 15 having a pressure receiving area which substantially corresponds to the passage cross section area of the suction passage 1 is disposed. More specifically, the pump has a structure where the single first check valve 15 in which the projected area (pressure receiving area) of the valve element 15B facing the suction passage 1 is set to a large value substantially corresponding to the passage cross section area of the suction passage 1 is disposed. Therefore, the inertia force is applied to the valve element 15B as a pressing force which is intensified in accordance with the large increased pressure receiving area. The large pressing force overcomes the spring force of the spring 15A to impede smooth "closing" of the valve element 15B, i.e., a smooth closing operation of the first check valve 15, thereby causing an improper operation such as chattering.
By contrast, even in a structure where the single first check valve 15 having a large pressure receiving area is used as described above, a spring 15A made of a metal may be used, so that the spring force is enhanced. In this case, even when a large pressing force is applied to the valve element 15B by the inertial force of the to-be-transferred fluid, the spring force of the spring 15A can overcome the pressing force to enable the first check valve 15 to conduct a smooth closing operation, and hence it is possible to prevent an improper operation such as chattering from occurring. In the case of a reciprocating pump to be applied to quantitative transfer of chemical liquids or ultrapure water to be used in processes such as washing of surfaces of ICs or liquid crystal display devices in a semiconductor producing apparatus, however, the use of the spring 15A made of a metal is restricted, and hence it is compelled to use the spring 15A made of a fluororesin material such as PTFE or PFA in which a high spring force cannot be expected.


The present invention provides a rubber composition with superior properties with respect to processability, low fuel consumption, complex modulus, and durability, and tires prepared by using the rubber composition. The rubber composition of the present invention comprises: 2 to 2.9 parts by weight of (B) sulfur, 0.6 to 10 parts by weight of (C) at least one compound selected from the group consisting of a cresol resin, a resorcin condensate, and a modified resorcin condensate, and 10 to 55 parts by weight of (D) a carbon black and/or silica, based on 100 parts by weight of (A) a rubber component comprising a natural rubber and/or isoprene rubber and at least two kinds of synthetic rubbers selected from the group consisting of butadiene rubber, modified butadiene rubber, styrene-butadiene rubber, and modified styrene-butadiene rubber. The tire of the present invention is prepared by using the rubber composition.

The present invention relates to a rubber composition and a tire using the same.
In recent years, tires have been required to exhibit better steering stability and ride qualities, for example, a dependable braking performance while running at a high speed.
With respect to technologies to improve steering stability of tires formed from fiber cords coated with a rubber composition, a method to improve complex modulus (E*) of the rubber composition and thus rigidity of the tires is known in the prior art. More specifically, a method of compounding a phenol resin in the rubber composition is known. However, there is a problem that a rolling resistance (tan δ) of the rubber composition thus obtained is increased.
For improving complex modulus (E*) and decreasing rolling resistance (tan δ), a method of crosslinking a resorcin condensate or a modified resorcin condensate using a partial condensate of hexamethylolmelaminepentamethyl ether (HMMPME) or a partial condensate of hexamethoxymethylolmelamine (HMMM) is well known. However, in such a case, during processing of the rubber composition into sheets or toppings, crosslinking starts, resulting in increase of a viscosity of the rubber composition and making its processability unsatisfactory.
Also, for improving complex modulus (E*) and decreasing rolling resistance (tan δ), an another method of blending a large quantity of sulfur or a vulcanization accelerator is known. However, the rubber composition thus prepared provides tires with unfavorable durability because of marked natural hardening during running.
Furthermore, in response to consumers' demands for tires assuring low fuel consumption, technologies for reducing fuel consumption have been actively developed in recent years by means of improvement on a tread or a sidewall.
As a result of progress in improvement for low fuel consumption associated with improvement of such large size elements as the tread and sidewalls, cord topping rubber becomes more important for further advancement of reduction of fuel consumption.
Although FEM analyses show that reduction in rolling resistance (tan δ) is effective in making the cord topping rubber contribute to low fuel consumption, no effective technologies to lower the rolling resistance (tan b) have been developed yet.
In reducing rolling resistance (tan δ), for example, a method of decreasing the content of carbon black or, on the contrary, a method of increasing the content of oil is known. However, when the content of carbon black is reduced, the rubber composition thus prepared has deteriorated breaking properties. When the content of oil is increased, in addition to deterioration in the breaking properties, durability of the rubber composition is also deteriorated due to migration of oil to such adjacent elements as sidewalls, an inner liner and cushion rubber.
JP2004-217817A discloses a rubber composition which comprises a compound capable of donating methylene groups and a resorcin resin, and are suitable for use at breaker edges. However, since the rubber composition comprises only a natural rubber and/or isoprene rubber as the rubber component and has a large content of sulfur (4 to 6 parts by weight), deterioration in physical properties is caused by reversion during vulcanization under high temperature. Therefore, improvements are still required.
An object of the present invention is to provide a rubber composition with an adequate level of hardness, and excellent processability, rolling workability, low fuel consumption, elongation at break, complex modulus, and durability, and another object of the present invention is to provide a tire using the rubber composition.


A computer-implemented method for populating and maintaining a local cache with archived data items is described. A request to organize archived data items into one or more bundles is sent. The one or more bundles of archived data items are downloaded to the local cache. Each of the archived data items are organized in the one or more bundles according to a time period associated with each archived data item. An index file is extracted from each of the one or more bundles. The extracted index file is inserted into a master index file.

The use of computer systems and computer-related technologies continues to increase at a rapid pace. This increased use of computer systems has influenced the advances made to computer-related technologies. Indeed, computer systems have increasingly become an integral part of the business world and the activities of individual consumers. Computer systems may be used to carry out several business, industry, and academic endeavors. The wide-spread use of computers has been accelerated by the increased use of computer networks, including the Internet. Many businesses use one or more computer networks to communicate and share data between the various computers connected to the networks. The productivity and efficiency of employees often requires human and computer interaction.
Users of computer technologies continue to demand that the efficiency of these technologies increase. These demands include demands to improve security related to information that may be created on a computer and/or shared between users of multiple computers. For example, users of computer technologies may store copies of data items in the event of a system failure that may render the data items inaccessible. In other words, users of computer technologies may archive copies of the data items in order to preserve the data in the event the original data is lost or corrupted.
Archived data may be accessed from the location via a network connection. An individual, however, may not always be in a location that allows him/her to connect to the secure network connection to retrieve archived data. As a result, benefits may be realized by providing improved systems and methods for populating and maintaining a local cache of archived data items so that a user may access these archived data items even when a network connection is unavailable.

Systems and methods for populating and maintaining a local cache with archived data items


Systems and methods for communication are disclosed. A system in accordance with the present invention comprises a communications system, comprising at least one transmitter station and at least one receiver station, the transmitter station and receiver station communicating using an Orthogonal Frequency Division Multiplexing (OFDM) schema, wherein OFDM signals are transmitted in a notched frequency band arrangement such that at least one other transmission within a notch of the notched frequency band is used outside of the communications system.

1. Field of the Invention
The present invention relates generally to data transmission, and in particular, to a method, apparatus, and article of manufacture for a reconfigurable notched spectrum for wireless data transmissions.
2. Description of the Related Art
Mobile telecommunications devices have become commonplace. Currently, wireless devices, e.g., cellular telephones, Personal Data Assistants (PDAs), and other devices are sending voice, pictures, video, and other data using Radio Frequency (RF) transmission and reception in cellular telephone systems.
Recently, many cellular providers have begun delivering video clips and other video delivery to cellular telephones and other handheld devices for viewing by a subscriber using higher speed data communications systems. Such delivery requires a large amount of bandwidth of dedicated spectrum for cellular telephones, typically in the 850 MHz or 1900 MHz range of cellular and PCS frequency bands.
Other types of high speed broadband RF transmission systems are possible, such as satellite transmission of voice, data, and video, however, the mobile devices used in such systems are typically much larger than desired because of the additional distance that transmissions from the mobile device are required to travel. The additional distance requires the mobile device to have a larger transmitter power, larger antenna, and, as such, are not quite as desirable to many users.
Further, wireless device users want to be able to use the portable and mobile devices anywhere, including inside of buildings. As such, the systems that support such devices must have a high enough signal strength to penetrate buildings and other structures so that users can operate their mobile devices over a large geographic area without worrying about any interruption of service.
Another typical problem for competing mobile devices is spectrum allocation. The RF frequencies available for transmission are extremely limited, because there are other competing governmental and private entities that have licenses to the frequency spectrum. Further, large contiguous portions of spectrum that would support broadband wireless services are not commonly available for many frequency bands. Only small portions of previously-allocated frequency bands are available, since those portions may not be currently in use by the spectrum owners. Typically, such a small portion is of no use to others, since the portion is not enough to support an entire broadband communications system.
It can be seen, then, that there is a need in the art for portable handheld and mobile devices that can receive broadband data. It can also be seen that there is a need in the art for a mobile device that can be used in a large number of places, including inside buildings, with minimal service interruption. It can also be seen that there is a need in the art for a communications system that can transmit and receive by aggregating smaller parts of the frequency spectrum into a single larger communications channel for use in a broadband service. Such a system can be used to provide fixed broadband service while at the same time providing next generation broadband access for portable and mobile wireless users.

This patent is subject to a terminal disclaimer.

Reconfigurable notched spectrum for wireless data transmission


Fluid pumps and medical treatment devices, in particular dialysis machines, include devices configured such that operating pressures and flow rates of the fluid pumps assume desired characteristics, in particular constant values or controlled profiles. The operating point of a peristaltic hose roller pump is adjusted based on an angle of rotation of a pump rotor, or by adjusting the operating point of a centrifugal pump in accordance with a profile.

1. Field of invention
The invention relates to the field of liquid pumps in medical treatment devices.
2. Description of the Prior Art
Medical treatment devices are in particular blood treatment devices. Blood treatment devices comprise dialysis machines which can be subdivided into hemodialysis machines and machines for performing automated peritoneal dialyses.
Dialysis is a method of purifying the blood of patients with acute or chronic renal insufficiency. Fundamentally, a distinction is made here between methods having an extracorporeal blood circulation such as hemodialysis, hemofiltration or hemodiafiltration (summarized below under the term "hemodialysis") and peritoneal dialysis, which does not have an extracorporeal blood circulation.
In hemodialysis the blood in an extracorporeal circulation is passed through the blood chamber of a dialyzer, which is separated from a dialysis fluid chamber by a semipermeable membrane. The dialysis fluid chamber has a dialysis fluid containing the blood electrolytes in a certain concentration flowing through it. The substance concentration of the dialysis fluid corresponds to the concentration of the blood of a healthy person. During the treatment, the patient's blood and the dialysis fluid are passed by both sides of the membrane, usually in countercurrent at a predetermined flow rate. Substances that must be eliminated in urine diffuse through the membrane from the blood chamber into the chamber for the dialysis fluid, while at the same time electrolytes present in the blood and in the dialysis fluid are diffusing from the chamber of the higher concentration to the chamber of the lower concentration. If a pressure gradient is built up from the blood side to the dialysate side on the dialysis membrane, for example, due to a pump which withdraws dialysate from the dialysate circulation downstream from the dialysis filter on the dialysate side, water enters the dialysate circulation from the patient's blood through the dialysis membrane. This ultrafiltration process leads to the desired withdrawal of water from the patient's blood.
In hemofiltration, ultrafiltrate is withdrawn from the patient's blood by applying a transmembrane pressure in the dialyzer without passing dialysis fluid by the membrane of the dialyzer on the side opposite the patient's blood. In addition, a sterile and pyrogen-free substitute solution may be added to the patient's blood. We speak of pre-dilution or post-dilution, depending on whether this substitute solution is added upstream or downstream from the dialyzer. The mass exchange takes place by convection in hemofiltration.
Hemodiafiltration combines the methods of hemodialysis and hemofiltration. Thus a diffusive mass exchange takes place between the patient's blood and the dialysis fluid through the semipermeable membrane of the dialyzer, and the plasma water is also filtered through a pressure gradient on the membrane of the dialyzer.
Plasmapheresis is a method blood plasma is separated from corpuscular components of blood (cells). The separated blood plasma is purified or replaced by a substitution solution and return to the patient.
In peritoneal dialysis, the patient's abdominal cavity is filled with a dialysis fluid through the abdominal wall such that the dialysis fluid has a concentration gradient with respect to the endogenous fluids. The toxic substances present in the body enter the abdominal cavity through the peritoneum, which acts as a membrane. After a few hours the dialysis fluid, now spent, which is in the patient's abdominal cavity is replaced. Water can travel from the patient's blood through the peritoneum and into the dialysis fluid by osmotic processes, thereby withdrawing water from the patient.
Dialysis methods are usually performed with the help of automatic dialysis machines such as those already distributed by the applicant under the brand name 5008 or sleep.safe.
To convey fluids in medical treatment devices, pumps of different designs are used. Peristaltic hose roller pumps are often used with machines having an extracorporeal blood circulation, such as hemodialysis machines. These hose roller pumps are often used in medical technology because they permit contactless transport of a fluid. In addition, they theoretically supply a flow which is proportional to the rotational speed over a wide range independently of the flow resistances upstream and downstream from the pump. In the case of a blood pump in extracorporeal treatment methods, the incoming (suction) side is referred to as the arterial side with an adjusted vacuum of typically approx. −100 to −300 mm mercury column in comparison with the outside pressure, and the efferent side is referred to as the venous side with a reduced pressure in comparison with the outside pressure.
DE3326785A1 discloses a typical embodiment of such an occlusive hose roller pump, according to which the delivery medium is moved by means of a periodically occluded hose.
In terms of the basic concept, a roller pump has a stator and a rotor. The stator is designed on the pump housing and has a recess with whose smoothly running vertical wall a pump hose is in contact. The area in which the pump hose is in contact with the wall forms the pump bed, which has the contour of a detail of a circle.
The axis of rotation of a rotor having rotatably mounted rollers on its free ends passes through the midpoint of this section of a circle. In rotation of the rotor in the working direction, the rollers come in contact with the pump hose, which is in contact with the circular contour of the circle of the pump bed and compress it to such an extent as it rotates further that it forms a fluid-tight seal (occlusive).
The delivery medium in the pump hose is conveyed further by further rolling of the rollers on the pump hose. In most cases, such a rotary pump has two rollers, which are mounted on the rotor in such a way that the connecting line passes through the axis of rotation of the rotor.
Other types of pumps which may be used include, for example, centrifugal pumps, diaphragm pumps or gear pumps.
The type of pump is definitive for the stress on the medium to be conveyed. This is important in particular in the case of an extracorporeal blood circulation because the blood can be damaged by pumping, and this may destroy erythrocytes, i.e., the red blood cells in particular (hemolysis). This may occur mechanically in particular, e.g., due to squeezing inside a blood hose or due to excessively high pressures.
A pulsatile non-steady-state flow, which is caused by the continuing engagement of the rollers in the pump hose segment, is characteristic of a hose roller pump. When the rollers mesh with the hose segment, the hose is squeezed together, thereby displacing the fluid. This fluid is displaced both in the direction of flow and opposite the direction of flow. Upstream from the roller, the displaced fluid is superimposed on the flow in the direction of the pump during ongoing operation and thus results in a short-term net reduction inflow, so that the arterial pressure becomes less negative until the hose is completely occluded. Then the fluid in the hose is accelerated again and the arterial pressure drops again. Downstream from the hose roller pump there is a sudden drop in pressure as soon as the roller emerges from the pump segment and a pressure equalization occurs between the reduced pressure in the segment between the rollers, this segment having been enclosed so far, and the excess pressure downstream from the pump.
Pressure peaks (and/or flow peaks) may occur in the area of the puncture site of the needle which returns the extracorporeal blood to a patient, and may cause shearing forces which in the extreme case may lead to thrombosis (coagulation) on the vascular walls and may even lead to hemolysis. Upstream from the pump, high shearing forces may also occur in equalization between high- and low-pressure systems.
In addition, hose roller pumps may also be used in the area of hemodialysis for the addition of blood-thinning substitute fluids. The pressure pulses generated in this way influence the blood to be thinned although to a lesser extent than with the blood pump at least at the location where the substitute and the blood are mixed.
Another type of pump that is used is the impeller pump or centrifugal pump. Centrifugal pumps essentially contain a housing to hold an impeller to which a magnet is fixedly connected. The magnet can be rotated by a second rotating magnet contained in a stationary base so that the impeller is made to rotate and the liquid in the housing is moved from a liquid inlet to a liquid outlet. Due to the operating principle, centrifugal pumps supply a constant volume flow so that the output pressure of the fluid pumped is a function of the input pressure, the viscosity of the fluid and the rotational speed. Pressure pulses in the fluid conveyed as in the case of peristaltic pumps do not occur with centrifugal pumps in normal operation at a constant rate of rotation of the impeller. Therefore, this prevents hemolysis caused by pulsatile conveyance of blood.
When used in the extracorporeal blood circulation, in particular in hemodialysis treatments, it is often necessary to add medication to blood in a controlled manner. A typical example of medication is the addition of anticoagulants such as heparin in hemodialysis treatments to prevent the blood from coagulating in the extracorporeal blood circulation and thereby prevent the fine hollow fibers of the dialysis filter from becoming clogged.
Syringe pumps, which add heparin or another anticoagulant (e.g., citrate) to the blood upstream from a dialysis filter, are often used for this purpose. However, it is also provided that a medication may also be added to the blood by delivering the medication through a special device and into drip chamber.
EP2386324A1 discloses such a device. A medication dosing apparatus which releases doses of a medication into the drip chamber on the basis of pressure pulses in the drip chamber is proposed there. The pressure pulses are generated here by the pulsatile non-steady-state operation of a peristaltic pump which delivers a fluid, preferably blood, into the drip chamber. Thus a pulsating air pressure characteristic develops via the fluid level inside the drip chamber in the cycle of the peristaltic pump, leading to regular dispensing of droplets of medication into the drip chamber.
So far, when using steadily delivering peristaltic pumps, it has not been possible to control the dosing of medication in a variable manner, i.e., to suspend it or have it occasionally occur more often. With centrifugal pumps it has not been possible at all so far to operate the medication dosing apparatus proposed in EP2386324A1 because of the lack of pressure fluctuations.

Methods and devices for modulation of the operating point of liquid pumps in medical treatment devices


A compound for a tyre textile body ply skim. The compound has a cross-linkable, unsaturated-chain polymer base, a reinforcing filler composite, and a curing system having at least a curing agent and accelerants. The compound has 0.1 to 20 phr of a lignin derivative, 20 to 50 phr of a first carbon black with a surface area of 90 to 150 m2/g, and 5 to 20 phr of a second carbon black with a surface area of 10 to 40 m2/g.

As anyone skilled in the art knows, reinforcing plies are commonly used to reinforce the carcass, and the belts located between the carcass and tread.
The carcass defines the shape of the tyre, supports the load and transmits vehicle stress groundwards, and ensures fatigue resistance of the stressed areas. The belts serve to further increase tyre resistance by stabilizing the tread and safeguarding against shock and damage to the inner layers.
As will be obvious to anyone skilled in the art, the body ply skim must adhere firmly to the plies. In fact, poor adhesion of the body ply skim to the ply invariably results in a short working life of the tyre.


The invention relates to a process for preparing polyisocyanates having a high uretdione group content by phosphine-catalysed isocyanate oligomerization in the presence of organic carbonates and/or nitriles.

Aliphatic isocyanates having uretdione groups are valuable raw materials for, inter alia, producing polyurethane coatings. Products based on optionally branched, linear-aliphatic diisocyanates have a particularly low viscosity. Products based on cycloaliphatic diisocyanates are generally highly viscous to solid substances which can be used as elimination product-free, internally blocked crosslinkers in coating systems. A summary is provided in J. Prakt. Chem./Chem. Ztg. 1994, 336, 185-200.
Tris(dialkylamino)phosphines (DE-A 3 030 513), if appropriate in combination with cocatalysts (DE-A 3 437 635), display good selectivity for the formation of uretdione groups (uretdione selectivity). However, the serious problem of the high carcinogenic potential of their phosphorus oxides, e.g. hexamethylphosphoramide, stands in the way of their industrial use.
DE-A 3 739 549 discloses the catalytic NCO dimerization using 4-dialkylamino-pyridines, e.g. 4-dimethylaminopyridine (DMAP), although uretdione formation proceeds selectively only in the case of specific cycloaliphatic isocyanates such as isophorone diisocyanate (IPDI). Linear-aliphatic isocyanates such as hexamethylene diisocyanate (HDI) and also branched, linear-aliphatic isocyanates such as trimethylhexane diisocyanate (TMDI) and methylpentane diisocyanate (MPDI) give mainly strongly coloured, heterogeneous reaction products when DMAP and related compounds are used.
DE-A 1 670 720 discloses the preparation of aliphatic polyisocyanates having uretdione groups, with tertiary phosphines having at least one aliphatic substituent and also boron trifluoride and its adducts being used as catalysts. The uretdione selectivity here is temperature-dependent, and appreciable amounts of viscosity-increasing isocyanate trimers (isocyanurates and iminooxadiazinediones) and, particularly at temperatures of >80° C., other undesirable by-products such as carbodiimides or uretonimines are always formed.
One way of increasing the uretdione selectivity and decreasing the by-product formation is the use of specific, bulky phosphines having P-bonded cycloalkyl groups (EP-A 1 422 223, unpublished German Patent Application DE 10354544). The fact that the uretdione selectivity for a given phosphine catalyst can be improved by addition of additives or solvents has been examined in JP 11228524. According to this, nonaromatic solvents having a Hildebrand solubility parameter of greater than 7 cal1/2 cm−3/2 are suitable for preparing polyisocyanates rich in uretdione groups in the presence of phosphine catalysts. However, as has been able to be shown in the examples of the present patent application, this is not always reliably the case (cf. chloroform; Hildebrand parameter 9.3 cal1/2 cm−3/2, compared to N-methylpyrrolidone, NMP; Hildebrand parameter 11.3 cal1/2 cm−3/2). Consequently, a person skilled in the art cannot derive any general teaching as to which solvents are reliably suitable for increasing the uretdione selectivity and reducing by-product formation and which are not from JP 11228524.
In addition, numerous publications disclose carrying out isocyanate oligomerizations in the presence of solvents in general terms without, however, naming individual compounds and/or specifically indicating compounds which lead to an improvement in the uretdione selectivity and a reduction in by-product formation.
It has now been found that the paired use of phosphines and organic carbonates and/or organic nitriles as catalyst system has a particularly advantageous effect on the selectivity of uretdione formation.


An axial piston device for use with a hydraulic system is disclosed. The axial piston device may have a body defining at least one bore and having a central axis, a pump piston disposed within the at least one bore to at least partially define a pumping chamber, and a tiltable plate biased into engagement with the pump piston. The axial piston device may also have an actuator configured to selective tilt the plate relative to the central axis of the body to thereby vary a displacement of the pump piston within the at least one bore. The actuator may have a control piston operatively connected to move the tiltable plate, a rotary motor, and a valve driven by the rotary motor to control fluid communication between the control piston and a source of pressurized fluid to move the control piston.

Variable displacement pumps generally include a plurality of pistons held against the driving surface of a tiltable swashplate. A joint such as a ball and socket joint is disposed between each piston and the swashplate to allow for relative movement between the swashplate and the pistons. Each piston is slidably disposed to reciprocate within an associated barrel as the pistons rotate relative to the tilted surface of the swashplate. As each piston is retracted from the associated barrel, low pressure fluid is drawn into that barrel. When the piston is forced back into the barrel by the driving surface of the swashplate, the piston pushes the fluid from the barrel at an elevated pressure.
The tilt angle of the swashplate is directly related to an amount of fluid pushed from each barrel during a single relative rotation between the pistons and the swashplate. And, based on a restriction of the pump and/or a fluid circuit connected to the pump, the amount of fluid pushed from the barrel during each rotation is directly related to the flow rate and pressure of fluid exiting the pump. Thus, a higher tilt angle equates to a greater flow rate and pressure, while a lower tilt angle results in a lower flow rate and pressure. Similarly, a higher tilt angle requires more power from a driving source to produce the higher flow rates and pressures than does a lower tilt angle. As such, when the demand for fluid is low, the swashplate angle is typically reduced to lower the power consumption of the pump.
Some variable displacement pumps utilize a hydraulic piston to adjust the tilt angle of the swashplate. The hydraulic piston is connected to the swashplate and moved by an imbalance of forces on the hydraulic piston. As the hydraulic piston is moved to retract or extend, the tilt angle of the swashplate is increased or decreased. Movement of the hydraulic piston is generally controlled by way of a pilot or solenoid activated linear spool valve. Unfortunately, linear spool valves may lack accuracy in their control over movement of the hydraulic piston.
One attempt at improving control accuracy of the hydraulic piston is described in U.S. Pat. No. 4,205,590 (the '590 patent) issued to Stegner on Jun. 3, 1980. The '590 patent discloses a pump having a stationary housing surrounding a rotatable cylinder block adapted to be rotated by a shaft. The block has a pair of pump pistons arranged against a swashplate on opposite sides of the shaft. A fluid actuator is provided to control displacement of the pump pistons, and includes a first control piston and a second control piston linked to the swashplate. By regulating a flow of fluid to the control pistons, the control pistons can pivot the swashplate and thereby control a stroke length of each of the pump pistons.
The pump of the '590 patent also includes a lobed cylindrical valve spool, and a sleeve member that receives the valve spool. A polarized torque motor is connected to linearly move the valve spool relative to the sleeve by way of a flapper. When the flapper is moved by the motor in a first direction, the valve spool is urged to communicate pressurized fluid with the first control piston and drain the second control piston of fluid, thereby tilting the swashplate to increase a displacement of the pump pistons. When the flapper is moved by the motor in a second direction, the valve spool is urged to communicate pressurized fluid with the second control piston and drain the first control piston of fluid, thereby tilting the swashplate to decrease a displacement of the pump pistons. A return spring is situated to return the flapper to a neutral position. In this configuration, a force applied by the motor to the flapper will move the valve spool until a resistance of the return spring balances the force of the motor.
An articulated feedback mechanism is connected between the swashplate and the sleeve member of the '590 patent. As the swashplate tilts, the articulated feedback mechanism pivots and transfers the tilting motion to a linear motion of the sleeve member relative to the spool valve. When a desired angle of the swashplate is achieved, the sleeve member is sufficiently moved by the tilting motion to block fluid flow through the valve spool so as to maintain the desired angle.
In the pump configuration of the '590 patent, a change in current input to the torque motor will produce a proportional change in the valve spool position. A change in valve spool position will produce a change in the positions of the pump pistons, thereby changing the angularity of the swashplate about its tilt axis. The feedback mechanism moves through the same angle as the swashplate and, by its articulated connection with the sleeve member, slaves the sleeve member on the valve spool. Thus, a current applied to the motor will be proportional to a displacement of the pump.
Although the pump of the '590 patent may improve displacement control accuracy, it may still be limited. Specifically, the pump relies on precise control over the current applied to the motor in order to ensure displacement accuracy. If the applied current varies, the actual displacement may not match a desired displacement. And, as the components of the pump age or the pump is used in varying environments and for different applications, precise control over the current may be difficult to ensure. In addition, the flapper configuration may have low durability and responsiveness. Further, the linear translation of the valve spool may create dynamic fluid interactions that could reduce displacement accuracy of the pump.
The axial piston device of the present disclosure solves one or more of the problems set forth above and/or other problems.

Axial piston device having rotary displacement control