A battery powered computer system has a drive motor and a motor speed control. The motor speed control receives electrical power from an unregulated source in the computer, such as a battery. The motor speed control may include a pulse width modulator which pulsates received electric potential for use by the drive motor. The motor speed control may also contain control circuitry which controls the supply of pulsated electrical power to the drive motor. The control circuitry may also supply the pulsated voltage to the drive motor in duty cycles based on feedback from the drive motor to the control circuitry. For large voltage power supplies, the motor controller may have a voltage limiter to limit the maximum voltage from the power supply to the pulse width modulator.

1. Field of the Invention
The present invention generally relates to motor drives in computer systems and, more particularly, to motor drives in battery powered computer systems.
2. Description of the Related Art
Battery powered computer systems, that is, computer systems that can be wholly empowered by a battery or batteries, are well known in the art of computer systems. One of the major advantages of battery powered computer systems is the fact that a user is able to operate such a system without having to be in the immediate vicinity of or to otherwise depend upon conventional stationary power sources such as 110 volt wall sockets. Thus, battery powered computer systems may be operated at many more locations than systems that must be connected to a stationary power source to operate. A second advantage of battery powered systems is that fact that they are generally made small and light, so as to be easily transportable. "Notebook sized" computers weighing about 31/2 pounds, which can easily fit into a briefcase for travel, are presently not uncommon. Examples of battery powered computer systems include but are not limited to many laptop, notebook, pen-based, and sub-notebook systems.
A disadvantage of battery powered computer systems is the limited runtime of those systems. Runtime is defined as the amount of time for which the battery powered computer system can operate on its battery source (i.e., its battery or batteries) without replacing or recharging that source. There are two primary factors in determining runtime: battery capacity and power consumption rate. Battery capacity, or the amount of power that can be delivered by the battery source, generally relates to battery size among similar or identical types of batteries. Battery size among similar or identical types of batteries, in turn, generally relates to battery weight. Power consumption rate depends on the amount of power consumed by a given system, and the speed at which the given system consumes that power. Generally, the runtime of a battery powered computer system increases with an increase in battery capacity and/or with a decrease in power consumption rate.
Ideally, those skilled in the art would like to increase system portability (by reducing system size and weight) while increasing system runtime. Unfortunately, as may be gathered from the discussion above, attempting to increase system runtime by increasing battery capacity generally causes an increase in the size and weight of the system's battery source, which reduces portability. Thus, toward the goal of increasing battery powered computer system runtime, those skilled in the art have come to focus upon reducing the power consumption rate of battery powered computer systems. Ideally, decreases in power consumption rate can ultimately allow decreases in battery capacity (i.e., battery size and weight) with runtime still being acceptable.
One method of reducing the power consumption of a system is to reduce the power consumption of a component of that system. A component that consumes power within many battery powered computer systems is a drive motor. Battery powered computer systems typically contain drive motors to cause rotation for operation of media devices, such as hard disk drives and floppy disk drives. In a typical prior art battery powered computer system, a drive motor receives power from a motor controller, the motor controller receives power from a DC to DC converter, and the DC to DC converter receives power from a system power source. The system power source is usually the computer system's battery; however, power can be obtained from a temporary hook-up to a stationary power source such as a 110 volt wall socket that has been rectified into a DC power source. The DC to DC converter is typically a linear or switching regulator taking the power source and converting it to a preset DC voltage for use in the entire computer system. The motor controller typically contains a linear regulator further converting the DC to DC converted voltage into a voltage for use by the drive motor and for internal control circuitry for operating the drive motor.
To reduce the power consumption rate of drive motors, those skilled in the art have heretofore enabled motor controllers (via power management firmware) to shut down the drive motor after predetermined periods of inactivity. Such systems are equipped with a timing mechanism to track length of periods of time during which the drive is not used, and such systems are further equipped with structure for starting and stopping the drive motor. Once a drive is in a shut down state, a renewed need for use of the drive causes the system to restart or reactivate the drive motor. Once the drive is given a command to activate the motor, there is a delay in time until the drive motor reaches its operating speed. This delay is called the spin-up time delay. Although spin-up time delay is considered undesirable primarily, because the driven structure (e.g., hard disk) is unusable until driven at its operating speed!, the increased runtime obtained by reduced power consumption provided by shutting down the drive motor is usually considered to outweigh the undesirability of the delay. Still, minimizing the amount of spin-up time delay is an important, desired goal in the art.
Spin-up time delay is in part determined by the electrical potential supplied to the motor controller and the drive motor. The greater the amount of electric potential applied to the drive motor, the faster it "spins up". Existing battery powered computer systems supply voltage to the drive motor indirectly and to the motor controller directly from a DC to DC converter. A typical DC to DC converter supplies only 5 volts to the drive motor and the drive motor controller. It is a shortcoming and deficiency of the prior art that there is not an easy way to apply a greater amount of electrical potential than 5 volts to the drive motor.
Another disadvantage of the current methods for powering drive motors is power loss in the DC to DC converter. As previously explained, the DC to DC converter takes voltage from a source such as the system battery and changes the voltage from that source into a voltage for use by the computer system. The typical efficiency for existing DC to DC converters is about 90%. This means that about 10% of the energy taken from the power source is lost, principally as heat. It is a shortcoming and deficiency of the prior art that current methods for powering drive motors have this power loss.
A further disadvantage of the current methods for powering a drive motor is power loss in the motor controller. In addition to controls for the motor, the motor controller contains a linear regulator for converting the DC voltage from the DC to DC converter into a voltage for use by the motor. For example, the linear regulator within the motor controller may receive a voltage (such as 5 volts) from the DC to DC converter (drawing 1 amp) and convert that voltage into a voltage (such as 3 volts) for use in the drive motor. In this example, two watts of power are lost in the linear regulator (generally as heat). It is a shortcoming and deficiency of the prior art that current methods for powering drive motors have this power loss.
Based upon the foregoing, it should be appreciated that there are a number of significant shortcomings and deficiencies in the art that have heretofore contributed to spin-up time delays incurred in the interest of increasing system runtime. These shortcomings and deficiencies include no provisions for applying higher voltages to drive motors, no provisions for eliminating power losses in the DC to DC converter in the source-converter-controller chain that empowers the drive motor, and no provisions for eliminating power losses in the motor controller in the source-converter-controller chain that empowers the drive motor.

System and method for controlling a computer drive motor


An element made of a reinforced low density heat protective material including an elastomer and/or a silicon resin matrix loaded with organic and/or inorganic components, wherein the reinforcement is formed of glass or ceramic thread sections or the like or organic materials fitted in the mass of the matrix along directions approximately orthogonal to at least one of the faces of the element and being flush, at least at one of their extremities, with at least one of the faces. The method for obtaining this element, includes, after molding to the general dimensions and shapes of the element with the aid of a loaded silicon matrix, placing the thread sections by stitching.

When returning into the atmosphere, a vehicle, such as a probe, capsule inhabited vehicle, etc., needs to confront the intense heat flows and consequently the most exposed portions need to be heat-protected.
To combat the heat flows, thermic insulating materials, known as ablative materials, are used to coat the structures to be protected and whose gradual destruction under the action of the heat flow impelled by a re-entry into the atmosphere protects the coated structure from the heat by means of various mechanisms summed up as follows:
storage of energy resulting in a rise of the internal temperature of the ablative material; PA1 endothermic reaction, namely : depolymerization, fusion, sublimation, vaporization; PA1 energy loss via radiation; PA1 flow of gaseous substances opposing the heat flow.
This protection via the destruction of the thermic insulant is one of the most effective means available to combat the intense heat flows produced by an atmospheric return.
This type of material, known for a large number of years, is formed of an elastomer and/or a silicon resin. There is a RTV (Room Temperature Vulcanization) type elastomer loaded with organic components (carbonated compounds, cork) or inorganic (SiC, silica, aluminium).
This material is used as such and placed in the form of panels or mounted elements, especially glued elements, onto the surface to be protected.
So as to prevent a possible flowing of the ablative material under the heat flow, the constitutive matrix of the material, composed, for example, of a RTV elastomer, silica ecospheres and phenolic microballoons and/or other loads, is inserted in a honeycomb type structure.
Thus, it is possible to embody light, flat and mechanically resistant coating panels offering heat protection and good refractory properties.
Furthermore, by using honeycomb structures being flexible in various directions; it is possible to embody bent structures.
This technique consists of preparing the honeycomb structure, for example by indenting the walls of the cells so that the structure can be bent, followed by lining the cells of a siliconed matrix with a suitable formulation, of compacting the matrix and then shaping the entire unit in a press.
However, the flexibility of this honeycomb structure has limits concerning the degree of bending of the panels able to be made according to this technique which moreover poses the problem of filling which needs to be thorough without having any vacuum in the cells of the honeycomb structure.
Finally, the reinforcement constituted by this structure needs to be homogeneous concerning the entire weight of the final panel which does not make it possible to differentially reinforce the panel according to its various portions. For example, as it concerns a leading edge panel, it is not possible to significantly reinforce the most exposed portions of the panel, the reinforcement technique, as described earlier, proceeding by all or nothing.

Element made of a reinforced low density heat protective material and method to obtain said element

Aerospatiale Societe Nationale Industrielle


A screw device is provided which can facilitate management of a tolerance of a recess where a circulation component is housed. A circulation component is housed in a recess of a nut with clearance. At least part of the circulation component is blocked by a lid member fixed to the nut by fastening means. Upon a centrifugal force acting on a rolling element moving along a circulation path in the circulation component, the circulation component comes into contact at three points with the recess as viewed in an axial direction.

A screw device includes a screw shaft, a nut, and a plurality of rolling elements disposed between the screw shaft and the nut. When the screw shaft rotates relatively to the nut, the rolling elements perform rolling motion between them, and the nut moves in an axial direction. The screw device has a feature that the light movement of the nut can be obtained by using the rolling motion of the rolling elements and is widely used as a mechanical element.
In order to circulate rolling elements in a known screw device, a return path in the axial direction is formed in a nut and a recess is formed in an end surface or outer peripheral surface of the nut. A circulation component is fitted into the recess. A circulation path connecting a groove of the nut and the return path of the nut is formed in the circulation component. The rolling element that has rolled to one end of the groove of the nut is scooped into the circulation path of the circulation component, and returns to the other end of the groove of the nut via the return path and a circulation path of the other circulation component (refer to Patent Literature 1).
In order to connect the circulation path of the circulation component and the groove and the return path of the nut without a level difference in the known screw device, the circulation component is fitted into the recess of the nut within a predetermined tolerance. The circulation component is then fixed to the nut using a screw.


Crystalline aripiprazole Type II can be formed without solid state heat treatment. Instead a liquid is used such as in crystallizing from a solvent, especially 2-propanol, dimethyl sulfoxide, or a combination thereof with ethyl acetate, or in a solvent mediated solid-solid transformation, typically in ethyl acetate.

The present invention relates to processes of making a crystalline form of 7-[4-[4-(2,3-dichlorophenyl)-1-piperazinyl]butoxy]-3,4-dihydrocarbostyril, also known as aripiprazole.
Aripiprazole is a compound of the formula (1).
It is a commercially marketed, pharmaceutically active substance useful for treatment of schizophrenia. It is disclosed in EP 367141/U.S. Pat. No. 5,006,528. The commercially marketed product is the free base of the title compound (1).
Solid state aripiprazole was prepared in U.S. Pat. No. 5,006,528 by a two-fold recrystallization of crude aripiprazole from ethanol resulting in colorless flake crystals having a melting point of 139-139.5° C. In an article of Aoki (Study on Crystal Transformation of Aripiprazole, The Fourth Japan-Korea Symposium on Separation Technology, p.937 ff (1996)), this solid state form was designated as Type I aripiprazole and identified as an anhydrate. Aoki also teaches that the Type I aripiprazole may be converted into a Type II aripiprazole by heating at 130-140° C. for 15 hours. This product is an anhydrate as well with a melting point of 150° C. When both Type I and Type II aripiprazole were recrystallized from an alcoholic solvent containing water up to 20%, the product is an aripiprazole hydrate labeled as Type III by Aoki. Type III aripiprazole can be converted into Type I by heating at 80° C.
WO 03/26659 (EP 1330249) teaches that the Type I aripiprazole, the alleged original solid form of aripiprazole, is significantly hygroscopic. This document also disclosed other crystalline forms of aripiprazole. One form (Form A) is a hydrate, the remaining (Forms B-G) are low hygroscopic anhydrates, differing with arrangement of molecules in the crystalline lattice.
It would be desirable to form crystalline Type II of aripiprazole without the need for a heat treatment or heat conversion. In particular, it would be desirable to find an alternate, economically more advantageous process, which does not require long-term exposure to high temperatures.

Process of making crystalline Type II aripiprazole


An elastomeric composition including a natural or synthetic rubber, and a cyclic dimerate ester and/or a cyclic trimerate ester plasticizer.

A number of elastomers are very difficult to plasticize. For example, elastomers, such as EPDM, are difficult to plasticize since it is difficult to find plasticizers that are sufficiently compatible to avoid the plasticizer exuding (bleeding) to the surface of the elastomer upon cooling and solidification of the elastomer. Usually, hydrocarbon oils such as naphthenic oils or paraffinic oils are used to plasticize elastomers such as EPDM. While hydrocarbon-based processing oils can be used with partial success, the resulting plasticized compositions lack advantageous low temperature properties and the processing oils have a tendency to exude (bleed) to the surface of the elastomeric article. Attempts to use conventional linear dibasic acid esters, such as dioctyl adipate, dioctyl sebacate, and di-2-ethylhexyl sebacate, or phthalate esters, such as di-2-ethylhexyl phthalate, have also been unsuccessful since such conventional ester plasticizers are either incompatible with the elastomer, resulting in exudation of the plasticizer, or are too volatile for many elastomer uses.
U.S. Pat. No. 5,290,886 teaches using organic ester plasticizers to plasticize thermoplastic elastomers comprising a blend of a thermoplastic polyolefin and an elastomer to lower the glass transition temperature (Tg) of both the elastomer and the polyolefin phases and to improve impact strength at low temperatures. The '886 patent neither discloses nor suggests using the cyclic dimerate and/or cyclic trimerate esters disclosed herein, and found that "polymeric dibasic esters and aromatic esters were found to be significantly less effective" (column 3, lines 62–64).
Dimer acid esters have been proposed as plasticizers for high temperature resistant fluorocarbon polymers (see U.S. Pat. No. 4,078,114) and for plasticizing anhydride-functionalized polymers (see U.S. Pat. No. 5,169,716) but have not been suggested for plasticizing non-fluorocarbon polymers, non-anhydride-functionalized polymers, or elastomers. It is preferred that the elastomers plasticized with the dimerate and/or trimerate esters disclosed herein are not fluorocarbon polymers, fluorocarbon elastomers, anhydride-functionalized polymers, or anhydride-functionalized elastomers.
Surprisingly and unexpectedly, dimerate and/or trimerate esters designed to have very low polarity act as efficient plasticizers for elastomers. The resulting plasticized compositions have excellent low temperature properties and exhibit little or no tendency of the plasticizer to exude or bleed to the surface of the elastomer composition. Use of the dimerate and/or trimerate esters as disclosed herein provides an advantageous balance of flexibility, impact resistance, and strength to the plasticized elastomers.

This patent is subject to a terminal disclaimer.

Low polarity dimerate and trimerate esters as plasticizers for elastomers


A voltage controlled oscillator includes first and second variable capacitance circuits 120 and 130, and first and second capacitance switch circuits 140 and 150. A control voltage Vt is fixedly applied to the first variable capacitance circuit 120, and control signals Fsel2 and Fsel3 are fixedly applied to the first and second capacitance switch circuits 140 and 150, respectively. When both of the control signals Fsel2 and Fsel3 are at a low level, the control signal Fsel1 is applied to the second variable capacitance circuit 130. When the control signals Fsel2 and Fsel3 are both not at the low level, the control voltage Vt is applied to the second variable capacitance circuit 130. As a result of this control, a high-frequency variable range is divided into two variable ranges, one based on upper frequencies and the other based on lower frequencies. This enables suppression of a frequency sensitivity without narrowing the high-frequency variable range.

A voltage controlled oscillator is widely used as means for generating a local oscillation signal for a wireless communication device. When the voltage controlled oscillator is manufactured as a radio frequency IC, it is necessary to increase an oscillation frequency range thereof, in order to accommodate variations among components thereof, which occur in a semiconductor manufacturing process. Moreover, in recent years, a demand arises that an oscillation frequency of a voltage controlled oscillator be adjustable in a wide frequency range so as to adapt the voltage controlled oscillator to communication systems using different frequency bands.
FIG. 13 is a diagram showing an exemplary configuration of a conventional voltage controlled oscillator 1d having an increased oscillation frequency range (for example, Patent Document 1). In FIG. 13, the conventional voltage controlled oscillator 1d includes: an inductor circuit having inductors 3; a first variable capacitance circuit formed with variable capacitance elements 4; a second variable capacitance circuit formed with variable capacitance elements 5; a third variable capacitance circuit formed with variable capacitance elements 6; a negative resistance circuit formed with transistors 9; a bias circuit 16; and switches 54 and 55. The inductor circuit, the first to third variable capacitance circuits, and the negative resistance circuit are connected in parallel with each other, and thus form an oscillation circuit.
In the conventional voltage controlled oscillator 1d, the switch 54 or 55 switches the direction of connection of a capacitance value control terminal of at least one of the two variable capacitance elements 5 and 6 which are provided in parallel with each other. This can cover different oscillation frequency ranges in accordance with the switched direction of connection. Thus, a plurality of kinds of oscillation frequency characteristics, having a lowered frequency sensitivity, can be obtained. The frequency sensitivity indicates a rate of variation of the oscillation frequency with respect to a frequency control voltage.
Patent Document 1: Japanese Laid-Open Patent Publication No. 2007-104152

Voltage controlled oscillator, and PLL circuit and wireless communication device each using the same


A marine vessel equipped with a countermeasure system having a substantially vertical launch tube that is at least generally rotatable about a vertical reference axis that extends through and along a length of the launch tube. This rotation capability of the launch tube may be used to affect an aiming of an associated countermeasure cartridge at least generally disposed therein. One or both the launch tube and countermeasure cartridge of this countermeasure system are generally equipped with a rotation inhibitor for substantially preventing independent rotation of the countermeasure cartridge relative to the launch tube at least when the countermeasure cartridge is disposed within the launch tube. The present invention is also designed to enable the associated countermeasure cartridge to be pitched over to a predetermined pitch angle (relative to the reference axis of the launch tube) to affect a desired flight path after launch of the countermeasure cartridge.

A number of devices have been employed on naval ships for protection from, among other threats, anti-ship missiles. These anti-ship missiles exhibit a wide variety of missile technologies including infrared-seeking and/or radar-guided missiles. Various countermeasure systems, have been employed in naval ships to protect against these anti-ship missiles, for example, by providing false signals to "confuse" guidance and/or fire control systems of the anti-ship missiles.
Conventional countermeasure systems (e.g., the MK 36 launcher system) are generally mounted on the ship's main deck. These launchers typically include any appropriate number (e.g., six) of launch tubes (e.g., 130 mm diameter) that are fixed in orientation (e.g., some at 45 degrees and some at 60 degrees) relative to the ship's main deck. Further, each countermeasure cartridge is generally designed to protrude out from or extend beyond the corresponding launch tube with which it is associated. The design, orientation, and location of these conventional launchers at least generally increases both the radar cross-section (e.g., visibility) and the visual outline of the ship. As another example of conventional countermeasure systems, what are referred to in the art as "trainable" launchers are also generally mounted on the ship's main deck, often protruding above the deck even further than the fixed angle MK 36. Accordingly, these trainable launchers present an even less stealthy profile than the MK 36 and additionally take up a significant portion of deck space. In the cases of both the MK 36 and trainable launchers, multiple launchers are positioned at a plurality of locations on the main deck of the ship. For example, two launchers may be positioned near the fore end of the ship, and two launchers may be positioned near the aft end of the ship.
In light of conventional ship-detecting systems, future surface combat ships (e.g., DD(X), CG(X), and LCS (Littoral Combat Ship)) are being designed as "stealthy smart" ships. That is, these combat ships are preferably being configured to avoid (or at least reduce a tendency for) detection of the same. Indeed, these combat ships are being designed to preferably exhibit minimum signatures across the electromagnetic spectrum (e.g., including RF (radar), visual, and IR (infrared) wavelengths). In order to achieve such a stealthy profile, the ships will ideally be low in the water, have sloped sides, and/or have no unnecessary protrusions above the main deck. Accordingly, employment of the above-described conventional countermeasure systems on the decks these combat ships will most likely take up significant amounts of space on the main deck, as well as at least generally reduce the preferred stealthy profiles of such ships.

Methods of using a marine vessel countermeasure system


The present invention relates to methods of monitoring, via polymerase chain reaction, the clinical progression of human immunodeficiency virus infection and its response to antiretroviral therapy. According to the invention, polymerase chain reaction assays may be used to predict immunological decline and to identify, at an early stage, patients whose infection has become resistant to a particular antiretroviral drug regimen.

Human immunodeficiency virus (HIV) isolated from patients treated with zidovudine (AZT) may demonstrate markedly reduced in vitro susceptibility to AZT (Larder et al., 1989, Science 243:1731-1734; Rooke et al., 1989, AIDS 3:411-415; Land et al., 1990, J. Infect. Dis. 161:326-329; Boucher et al., 1990, Lancet 336:585-590; Japour et al., 1991, Proc. Natl Acad. Sci. 88:3092-96; Tudor-Williams et al., 1992, Lancet 339:15-19). This reduced susceptibility has been related to the duration of therapy with AZT and the severity of HIV disease at the time AZT therapy is begun (Richman et al., 1990, J. AIDS 3:743-756). Nucleotide sequence analysis of AZT-resistant HIV strains has revealed a number of mutations in the reverse transcriptase (RT) gene associated with decreased AZT susceptibility (Larder et al., 1989, Science 246:1155-1158; Larder et al., 1991, AIDS 5:137-144; Kellam et al., 1992, Proc. Natl. Acad.Sci. USA 89:1934-1938; St. Clair et al., 1991, Science 253:1557-1559; Richman et al., 1991, J. Infect. Dis. 164:1075-1081). Molecular cloning experiments have confirmed that these mutations in the RT gene confer AZT resistance (Larder et al., 1989, Science 246:1155-1158; Larder et al., 1991, AIDS 5:137-144; Kellam et al., 1992, Proc. Natl. Acad.Sci. USA 89:1934-1938; St. Clair et al., 1991, Science 253:1557-1559). Of these mutations the one at codon 215 resulting in a single amino acid substitution (Thr.fwdarw.Tyr or Phe) has been shown to be the most common mutation and to have the greatest impact on in vitro susceptibility to AZT (Larder et al., 1991, AIDS 5:137-144; Richman et al., 1991, J. Infect. Dis. 164:1075-1081; Boucher et al., 1992, J. Inf. Dis. 165:105-110).
Several studies have addressed the relationship between in vitro AZT resistance, mutations in the RT gene and clinical disease. Richman and coworkers studied 32 patients with different stages of HIV disease and demonstrated that the development of in vitro AZT resistance was related to the duration of therapy with AZT and to the severity of disease at the time AZT was begun (Richman et al., 1990, J.AIDS 3:743-746). Boucher and coworkers studied HIV P24-antigenemic patients treated with AZT for 2 years. They observed that at 6 months, seven patients with a mutation at codon 215 had a weak, non-statistically significant trend toward lower CD4 counts compared to nine patients who were wild type at codon 215 (Boucher et al., 1990, Lancet 336:585-590). After 2 years nearly all patents had the mutation. Tudor-Williams and coworkers studied HIV isolates from 19 symptomatic children treated with AZT for 9-39 months and showed that in vitro AZT resistance was associated with poor clinical outcome (Tudor-Williams et al., 1992, Lancet 339:15-19). However, adult studies have not shown a precise correlation between the development of in vitro resistance and progression of HIV disease.

Polymerase chain reaction assays for monitoring antiviral therapy and making therapeutic decisions in the treatment of acquired immunodeficiency syndrome


A valve tester system is disclosed that comprises a valve tester assembly for rotating a valve stem of a valve. The valve tester assembly may include a support, a rotation element mounted on the support for rotating a valve during a rotation event, a control element for controlling aspects of the rotation event of the valve by the rotation element, and an element for detecting a location of the valve tester assembly during the rotation event of the valve. In some embodiments of the invention, the element for detecting the location of the valve tester assembly includes a Global Positioning Satellite (GPS) receiver. In some embodiments, the GPS receiver is integral with the control element.

1. Field of the Invention
The present invention relates to valve testing apparatus that rotate the valve control to open and close the valve, and more particularly pertains to improvements in valve testing apparatus that facilitate rotation of the valve in a manner that minimizes the potential for damage to the valve during the rotation event, and also facilitates accurate detection and recording of the most pertinent aspects of the rotation event for memorializing the rotation event for maintaining complete records of the maintenance of the valve.
2. Description of the Prior Art
Valves, particularly those used to control the flow of water in municipal distribution systems, spend virtually the entirety of their useful lives in either an open condition or a closed condition, with normally no movement between those conditions, especially if the valve is located underground in a distribution line or on a street hydrant. These long periods of remaining in a single state tends to make it difficult to change the condition of the valve in those few times when change is desired, such as in emergency situations when a leak develops in a pipe connected to the valve. Therefore, it is desirable to periodically "exercise", or rotate the control stem of the valve between the open and closed conditions not only to avoid freeze up due to long periods of in action, but also to verify that the valve is operational.
While these devices fulfill their respective, particular objectives and requirements, it is believed that these devices do not present a suitable solution for suspending a valve testing or exercising apparatus in a manner that facilitates the testing process by a single person and that easily adapts to variations in the orientations or positions of the valves often encountered under real world conditions.
A rotation event for a valve being tested typically includes rotating the control stem of the valve from one limit of travel (e.g., the fully open condition) to the other limit of rotation (e.g., the fully closed condition). This cycle may be repeated if desired, but is performed to establish that the valve is still functional.
Further, it has become increasingly desirable to record, both accurately and completely, various aspects of the valve exercising or rotation event. Because the valves to be tested are in typically in widely scattered and sometimes remote locations, the ability to record the pertinent information about the rotation event and bring that information back to a central database containing collected information about the valves is not only highly desirable, but may be critical to keeping valves operational in times of emergency. However, previous valve testing or exercising apparatus have relied heavily upon the operator to locate each of the valves to be tested, and accurately identify each of the particular valves being tested. While data regarding a particular valve rotation event may be recorded in an automated or automatic manner by the valve testing apparatus, the known systems rely entirely on the operator to accurately identify which valve is being tested during each rotation event. If the valve has not been accurately identified by the operator, which is certainly conceivable when the area of a single road intersection may have two, three, four or more different underground valves to be located and tested, the data that is recorded is not associated with the correct valve. Unfortunately, when the valve testing system relies solely upon the operator to identify the valve being tested, it is also conceivable that the same valve could be tested over and over but be "identified" as a number of different valves simply by entering a different valve identification for each "test", and such abuse may be hard to detect in the limited information recorded during the test.
Thus, there is a need for a valve testing apparatus that is capable of identifying different valves independently of the operator's identification so that mistakes in valve identification do not cause the test data from a rotation event to be associated with the wrong valve.


A positive swivel fitting provides for a system flow transmitting portion and a separate lock-down portion. The flow transmitting portion is configured to be receivable within the lock-down portion. When the flow transmitting portion is properly and “positively” positioned, then the lock-down portion can be secured and the position of the flow transmitting portion is maintained, thus making alignment with other parts of the flow device variable. The fitting can be used within any air, other gas or liquid flow system.

Connectors and couplers are well known in systems that allow or require "flow" between system components. Such systems can include, but are not limited to, systems that allow the flow of air, other gases and liquids through them. The positive swivel fitting of the present invention can be used in all such systems.
Further, where an inlet line or a pressure test nipple is provided within the flow system, it is frequently desirable to "point" the fitting in a given direction. By way of example, but without limiting the scope of the present invention, most flow components used in such systems require access to at least one flow inlet line and an inlet line coupler. The coupler is typically a threaded hollow conduit that is secured to some part of the component by means of a like-threaded aperture. Upon installation, the coupler may be aligned such that access to the coupler is made easy. On the other hand, proper alignment which would make access easy may not be possible due to the variability of threading between the parts. Because the coupler is capable of being pointed, or positioned, in virtually any direction within a 360° perimeter, it may not be pointed in a desirable or workable direction following installation. In other words, the coupler discussed here is incapable of "positive" positioning.
In the view of these inventors, the alignment problem mentioned above can be avoided. More specifically, and also in the experience of these inventors, such problems can be avoided where the rotational aspects of the system device are separated from the attachment aspects, and such is a principal object of the present invention.


A method of assessing radar pulses in a passive, i.e. receive-only, radar system to distinguish pulses due to a particular target from pulses due to other targets from noise, interference, etc. Received pulses are assessed, without reference to pulse transmission information, in respect of a number of characteristics by comparing each characteristic of a pulse with the mean value of the respective characteristic for pulses previously received. Using a probability process, confidence values for the pulse can be calculated. By combining the confidence values for each characteristic, an overall confidence value is obtained for the pulse so that it can be determined whether it arises from the particular target.

This invention relates to a method of assessing radar pulses in a passive receiving system to distinguish pulses due to a particular target from pulses due to other targets, from noise, interference etc. Received pulses may be assessed, without reference to pulse transmission information, in respect of a number of characteristics; for example, direction of reception (angle off boresight), power level, pulse width, pulse repetition interval (PRI), and also radio frequency, if an absolute measurement of frequency is available. Each of these characteristics, even in respect of a particular target, is subject to variation due to noise, interference etc., and significant tolerances have to be employed in the assessment of each pulse.
Conventional signal processing methods rely, in the case of active radars, on the known characteristics of the transmitted pulse. Such systems are primarily concerned with detection of target echoes among clutter. The receiver has a priori knowledge of the nature of the echo signal it is seeking to identify since it usually forms part of an active radar system, which has itself determined the transmitted pulse waveform. The task is, therefore, to pick out this known waveform from clutter and noise, and a comparison with the known pulse data is the obvious solution. This invention is directed to working in a much more demanding situation to identify a target which is emitting radar pulses that have not originated from the detecting radar. Thus, the target may well be a radar transmitter itself. In such a situation there is initially no foreknowledge of the received pulse waveform and it may have to be identified not so much from clutter as from other conflicting radar signals. Conventionally, passive, i.e. receive-only, radars have compared the value of the particular characteristic with preset limits and accepted or rejected the pulse accordingly. The tolerance band set for such a comparison leads to a significant probability of a wrong signal being accepted, with a consequent loss of ability to distinguish targets. This invention is directed to the statistical assessment of received pulses in respect of a number of characteristics by reference only to previously received pulses to establish a confidence value that a train of received pulses arises from a particular target.


A method for a parallel image reconstruction is disclosed. The method includes (a) acquiring image information by channel via parallel coils in a magnetic resonance imaging (MRI) scanner; (b) extracting low-frequency signals from the image information; (c) reconstructing low-frequency images from the low-frequency signals; (d) generating filter banks by using the low-frequency images; and (f) reconstructing a final image by using the filter banks. The generating of the filter banks includes separately generating low-frequency image information for reconstruction of magnitude information and low-frequency image information for reconstruction of phase information, and then separately generating a filter for reconstruction of the magnitude information and a filter for reconstruction of the phase information.

The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Parallel magnetic resonance imaging (pMRI) employs the following image reconstruction methods:
1. Simultaneous acquisition of spatial harmonics (SMASH)
2. Variable density-AUTO-SMASH (VD-AUTO-SMASH)
3. Generalized auto-calibrating partially parallel acquisitions (GRAPPA)
4. Multi-column multi-line GRAPPA: 2D-GRAPPA
5. Method and device for magnetic resonance imaging on the basis of a partially parallel acquisition (PPA).
SMASH is one of the methods for reconstructing images in k-space. SMASH acquires image information by performing sub-sampling in the ky-direction in k-space in order to reduce image acquisition time.
In this case, image information that is acquired from each channel may be represented by Equation 1:S(kx,ky)=∫∫dxdyCj(x,y)ρ(x,y)e-ikxx-ikyy  Equation 1
In Equation 1, Cj(x,y) is the sensitivity profile of a j-th channel, and ρ(x,y) is overall image information to be reconstructed. Assuming that Ccomp is the sum of values obtained by multiplying the sensitivity profiles of respective channel images by a specific constant, a value nj that allows Ccomp to become spatial harmonics may be acquired, as indicated in Equation 2 (see FIG. 1), and the constant by which the sensitivity profiles of respective channels should be multiplied in order to form Ccomp is estimated using the sensitivity profiles of the respective channels images.
                                          C            comp                                          (                          x              ,              y                        )                          =                                            ∑              j                                                                                n                j                                                                            C                  j                                                                  (                                      x                    ,                    y                                    )                                                              =                      exp                                      (                              im                                                                                Δ                                                                                k                  y                                                y                            )                                                          Equation                                                  2
When the constant that allows spatial harmonics to be formed is obtained and then multiplied by the channel images, information on locations adjusted by +m or −m in the ky-direction may be acquired, as indicated by Equation 3:
                                                                        S                                                  (                                                            k                      x                                        ,                                                                  k                        y                                            +                      m                                                        )                                            =                                                          ∫                                  ∫                                                            ⅆ                      x                                                                                ⅆ                      y                                                                                C                        comp                                                                                (                                                  x                          ,                          y                                                )                                                                                ρ                                                                    (                                                  x                          ,                          y                                                )                                                                                exp                                                                                -                            ⅈ                                                                                k                            x                                                                              x                                                -                                                  ⅈ                                                                                k                            y                                                                              y                                                                                =                                                          ∫                                  ∫                                                            ⅆ                      x                                                                                ⅆ                      y                                                                                ρ                                                                    (                                                  x                          ,                          y                                                )                                                                                exp                                                                                -                            ⅈ                                                                                k                            x                                                                              x                                                -                                                                              ⅈ                            (                                                                                k                                y                                                            +                                                              m                                                                                Δ                                                                                k                                  y                                                                                )                                                                              y                                                                                Equation                                                  3
Unacquired information is estimated with value nj acquired using the sensitivity profiles, as described above, thereby reconstructing the overall image information.
While SMASH is the first proposed algorithm for generating harmonics by using individual sensitivity profiles in k-space and then reconstructing an image as described above, it has disadvantage that it requires sensitivity profiles to reconstruct an image and cannot compensate for image distortion attributable to interference between channels (see Sodickson, D. K. & Manning, W. J. 1997. Simultaneous Acquisition of Spatial Harmonics (SMASH): Fast Imaging Radiofrequency Coil Arrays. Magnetic Resonance in Medicine, 38(4), 591-603).
VD-AUTO-SMASH is an improvement on SMASH. In VD-AUTO-SMASH, the process of acquiring a constant used for image reconstruction by using sensitivity profiles in SMASH is replaced with the process of acquiring auto-calibrating signal (ACS) information and estimating a constant based on data. Although VD-AUTO-SMASH takes a longer image acquisition time than SMASH for acquiring a plurality of pieces of ACS information, a constant used to generate harmonics can be estimated with higher accuracy.
VD-AUTO-SMASH is an improvement on SMASH and AUTO-SMASH. Unlike SMASH, AUTO-SMASH and later methods acquire a coil-weighting factor through the process of acquiring ACS information and then fitting the ACS information to sub-sampled information, as in the second process of FIG. 2. The image information of an unacquired location is acquired using the constant value acquired by the fitting process. In this case, if m is the distance in the ky-direction between the image information of an acquired part and image information to be acquired, that is, unacquired image information, the image information of an acquired part and the image information of the unacquired image information have a relationship formed via the coil-weighting factor and the sensitivity profile, as expressed by Equation 4:
                                                                                S                  ACS                                                                  (                                                            k                      x                                        ,                                                                  k                        y                                            -                                              m                                                                                Δ                                                                                k                          y                                                                                )                                            =                                                ∑                  j                                                                                n                    j                    m                                                                                S                      j                                                                                (                                                                        k                          x                                                ,                                                  k                          y                                                                    )                                                                                =                              ∫                                  ∫                                                            ⅆ                      x                                                                                ⅆ                      y                                                                                ∑                        j                                                                                n                          j                          m                                                                                C                            j                                                                                (                                                          x                              ,                              y                                                        )                                                                                ρ                                                                                (                                                          x                              ,                              y                                                        )                                                                                ⅇ                                                                                -                                ⅈ                                                                                k                                x                                                                                x                                                        -                                                          ⅈ                                                                                k                                y                                                                                y                                                                                =                              ∫                                  ∫                                                            ⅆ                      x                                                                                ⅆ                      y                                                                                ∑                        j                                                                                C                            comp                                                                                (                                                          x                              ,                              y                                                        )                                                                                ρ                                                                                (                                                          x                              ,                              y                                                        )                                                                                ⅇ                                                                                -                                ⅈ                                                                                k                                x                                                                                x                                                        -                                                          ⅈ                                                                                k                                y                                                                                y                                                                                Equation                                                  4
Value njm indicating the relationship between the ACS information and the acquired signal is obtained from Equation 4, and then an image is reconstructed using value njm. Since VD-AUTO-SMASH uses a plurality of pieces of ACS information, the constant njm for each channel j and value m is acquired by the weighted sum of the plurality of constants acquired by the plurality of pieces of ACS information.
VD-AUTO-SMASH has the advantage of performing the process of acquiring sensitivity profiles based on data by introducing the concept of ACS information, and also has a robustness to noise because it uses a plurality of pieces of ACS information. However, VD-AUTO-SMASH is susceptible to image distortion because it lacks a compensation against image distortion attributable to phase distortion between channels (see Heidemann, R. M., Griswold, M. A., Haase, A. & Jakob, P. M., 2001. VD-AUTO-SMASH Imaging. Magnetic Resonance in Medicine 45(6), 1066-1074).
GRAPPA acquires part of information in the ky-direction in k-space in order to reduce image acquisition time, as in SMASH or VD-AUTO-SMASH method. However, GRAPPA acquires additional information called ACS information, as in VD-AUTO-SMASH method, and then estimates the relationship between the ACS information and acquired line information. Thereafter, information on unacquired lines is estimated along the ky-direction by using the estimated relationship, thereby reconstructing the image (see FIG. 3).
In this case, GRAPPA can improve the quality of image by using the ACS information, as in VD-AUTO-SMASH. GRAPPA has a feature that images of respective channels are separately reconstructed. As a result, the performance of image reconstruction is improved, and image distortion attributable to phase distortion between channels can be eliminated when the images of respective channels are combined together by using a square root of sum of squares (SoS) reconstruction method.
However, GRAPPA requires a relatively long image reconstruction time when the number of channels is large since individual channel images are separately constructed, and bears disadvantage due to the inability to acquire the phase information of a final image when an image is reconstructed using the SoS method (see Griswold, M. A., Jakob, P. M., Heidemann, R. M., Nittka, M., Jellus, V., Wang, J., et al., 2002. Generalized Auto-calibrating Partially Parallel Acquisitions GRAPPA. Magnetic Resonance in Medicine, 47(6),1202-1210).
Multi-Column Multi-Line GRAPPA is an improvement on the above-described GRAPPA, and is referred to as "2D-GRAPPA." Existing GRAPPA uses only information in the ky-direction to reconstruct a missing line information. In contrast, 2D-GRAPPA additionally uses information in the kx-direction, as illustrated in FIG. 4, thereby improving the performance of image reconstruction. It is generally referred to as "2D-GRAPPA" because of its feature for reconstructing an image by using both information in the kx-direction and information in the ky-direction in k-space.
However, 2D-GRAPPA also requires separate reconstructions of images acquired for respective channels, like existing GRAPPA, inheriting the inability to acquire the phase information of a final image when the SoS method is used in combining the pieces of information of the respective channels (see Wang, Z., Wang, J. & Detre, J. A., 2005. Improved Data Reconstruction Method for GRAPPA. Magnetic Resonance in Medicine, 54(3), 738-742).
The "method and device for magnetic resonance imaging on the basis of a partially parallel acquisition" is a technology that is disclosed by U.S. Patent Application Publication No. 2009/0134870 A1. The image reconstruction process of the technology will now be briefly described. First, low-frequency images are generated by using low-frequency signals fully sampled from a plurality of pieces of image information acquired from respective channels. The low-frequency images of the respective channels are combined into a single sheet of combined image, the single combined image is subjected to inverse Fourier transform, and then image reconstruction is performed, as in GRAPPA. Using this process, the US patent application has the advantage of reducing image reconstruction time. Furthermore, the method can acquire both the magnitude and phase information of an image because a single image is reconstructed.
However, the performance according to the US patent application is variable depending on the method of combining individual channel images, and requires the process of acquiring or estimating a sensitivity map because it is essential to such method as an Adaptive Combine (see Vladimir Jellus, 2009. Method and Device for Magnetic Resonance Imaging on the basis of a Partially Parallel Acquisition (PPA), US Patent Application Publication No. 2009/0134870 A1).

Parallel image reconstruction using filter banks based on low-frequency part of k-space signals

Korea Advanced Institute of Science and Technology


A packet transmission apparatus transfers arriving packets directly to a highest-priority queue under non-congestion conditions, and classifies the priority of a packet only on the existence of congestion. In one embodiment, non-congestion is determined when all queues are empty. In another embodiment, congestion or non-congestion is determined by upper and lower thresholds on the total number of packets in all queues. The ability to omit classifying incoming packets in the non-congestion condition improves processing speed, and eliminates the need for re-queuing or packet-replacing operations.

1. Field of the Invention
The present invention relates to a packet transmission apparatus for transmitting packets using a plurality of queues and relates to a method therefor.
2. Description of the Related Art
This type of packet transmission apparatus has various forms, such as routers, switches, or boards that perform those main functions. WFQ (Weighted Fair Queuing) is most generally used as a scheduling method in this type of packet transmission apparatus. According to WFQ, band control is carried out for each priority class. In this method, queues corresponding to the number of priority classes are prepared, packets are transmitted according to a weight that has been set for each priority class. Thereby band assurance is offered.
In WFQ, when a packet arrives, a priority class is determined from the header of the packet. The packet is queued in a queue corresponding to the priority. A time stamp is given to the first packet of each queue. The packet having the smallest time stamp value (the oldest packet in the queue) is selected as the packet to be transmitted.
Therefore, (1) if the number of queues is n, then the calculation of O (log n) is required to determine a minimum value. Further, (2) even in the case where the number of packets is so small that processing according to priority is not needed, processing-overheads are large because a classification is made based on priority with respect to queues.
Accordingly, in order to realize higher-speed processing, Japanese Unexamined Patent Publication No. Hei-10-13463 discloses the following technique. A preferential flag is kept on with respect to a preferential packet both in a non-congestion state and in a congestion state. In the congestion state (i.e., in the state where a queue length has reached a threshold), the preferential flag extracts the on-packet so as to again queue it at a special queue corresponding to congestion, and preferentially transmits the packet queuing at the special queue corresponding to congestion.
As a result, FIFO (First In First Out) is realized in the non-congestion state. Therefore higher processing speed is achieved than is possible with WFQ.
However, if this technique is applied, the following disadvantages will arise.
(1) The classification by priority of packets that have arrived is regularly needed. Additionally, there is a need to operate preferential flags on the basis of the results of the classification. Therefore, time loss because of the classification is unavoidable even in the non-congestion state.
(2) Further, in the congestion state, since there is a need to extract flags that are in an ON-state with reference to the preferential flag of each packet and carry out re-queuing (i.e., replacement of a large amount of packets), a processing burden enormously increases. Additionally, in the congestion state in which the space for queues is almost full, if such burdened processing as above is carried out in addition to the processing of the packets that have arrived, there might arise a fear that the arriving packets cannot be processed in time, and therefore a malfunction, such as packet loss, is invited.

Apparatus and method for packet transmission

Matsushita Electric Industrial Co., Ltd.


A drive unit is provided including an electric motor and a pot-shaped drum driven by the electric motor. The drum accommodates the electric motor and is connected by means of its pot base to the drive-side shaft end of the electric motor. Improved power utilization of the electric motor is made possible by at least one web extending in the axial direction of the drive unit and projecting radially into the gap between the housing of the electric motor and the drum inner wall. The at least one web is arranged on the housing of the electric motor and/or on the drum inner wall and/or at least one through-hole is provided in the pot base of the drum.

Such a drive unit is disclosed in EP-A-0 423 616. In order to enable flow of a sufficient quantity of cooling air through holes in the pot base, axially projecting vanes are assigned to the holes on the outside of the pot base. If such a drive unit is not equipped with a separate protective grating, then there is an increased risk of injury from the projecting vanes.
When such a drive unit is used in textile operations, there is also a risk of fluff becoming trapped on the vanes and, consequently, of the holes provided in the pot base becoming blocked as a result of the normally high incidence of fluff. As a result, sufficient cooling of the motor inside the drum is no longer ensured.
Also, GB-A-2 160 924 discloses an axial fan in which the drive motor is seated in the hub, which is designed in the form of a bell, of the axial impeller wheel. Openings are provided in the transition region of the bell base, which is connected to the motor shaft, leading to the bell wall for passage of cooling air flow therethrough. This air flow passes between the surface of the drive motor and the inside of the bell wall. The cooling air flow receives its drive energy from the pressure difference produced between the two vane sides of the axial impeller wheel.


According to one aspect of the present invention, a printed circuit board includes: an insulating base film; a conductive pattern that is partially layered on a surface side of the base film; a coating layer that is layered on a surface of a layered structure including the base film and the conductive pattern and having an opening portion that partially exposes the conductive pattern; and a tin plating layer that is layered on a surface of the conductive pattern exposed from the opening portion, wherein an average peel length of the coating layer from the conductive pattern with an inner edge of the opening portion as a base end is less than or equal to 20 μm.

Printed circuit boards are widely used to construct electrical circuits such as electronic components. A printed circuit board typically includes a plate-like or film-like insulating substrate (base board or base film) and includes a conductive pattern that is provided on the insulating substrate. A conductive pattern typically includes a lead (terminal) portion or a land portion used to connect other printed circuit boards, electronic components, and the like.
In particular, as a technique for connecting an IC for driving a LCD (liquid crystal display panel) having a small wiring pitch to a printed circuit board, it is known that tin is plated on a lead portion of a conductive pattern of the printed circuit board and the IC for driving a LCD is connected by an eutectic reaction between the tin and gold on the terminal surface of the IC for driving a LCD (see Japanese Laid-open Patent Publication No. 2011-66181).
The printed circuit board described in the publication includes a solder resist film having an opening for exposing a land portion and is manufactured by selectively forming an electroless tin plating film on the land portion that is exposed in the opening of the solder resist film.

Printed circuit board and method of manufacturing printed circuit board

SUMITOMO ELECTRIC PRINTED CIRCUITS, INC.


A wireless communication system has wireless base stations that serve wireless communication devices located in a plurality of wireless communication sectors. The wireless communication devices have wireless device types. The wireless base stations generate performance data that characterizes the performance of the wireless device types in the wireless communication sectors. A data processing system processes the performance data to associate an abnormal condition with one of the wireless device types in one of the wireless communication sectors. The data processing system generates notice data for the one or more wireless device types associated with an abnormal condition. The wireless base stations broadcast the notice data in a Long Term Evolution (LTE) System Information Block (SIB). The notice data identifies the wireless device type. The wireless communication devices decode the LTE SIB to identify the notice data and the wireless device type. If the wireless communication device comprises the wireless device type identified in the notice data, the wireless communication device configures the wireless communication device based on the notice data.

Wireless communication devices communicate with wireless communication networks using wireless protocols, such as Long Term Evolution (LTE), Evolution Data Optimized (EVDO), Code Division Multiple Access (CDMA), Global System for Mobile communications (GSM), High Speed Packet Access (HSPA), and the like. Wireless communication systems, such as cellular voice and data networks, typically include multiple wireless access nodes spread over a geographic area through which wireless communication devices can register and receive wireless access to wireless communication services. In many examples, the wireless communication devices are mobile, and can move between wireless coverage areas, such as sectors, of the wireless access nodes.
Wireless communication devices have different device types. For example, wireless communication devices may be categorized by network type—such as LTE or non-LTE. Wireless communication device may also be categorized by manufacturer (Apple, Samsung, HTC, Nokia, etc.) and/or model (iPhone 4, iPhone 4s, iPhone 5, etc.). Alternatively, wireless communication devices may be categorized by operating system (Apple, Android, or Windows) and/or software version.
Signal strength, network load, and/or other factors may affect the quality of wireless communication service within and across wireless communication sectors. In addition, wireless communication devices of different device types may perform differently across the wireless communication sectors. Wireless communication service may be improved by turning off or disabling certain features on certain device types in certain wireless communication sectors.

Wireless communication system to detect an abnormal condition associated with wireless communication device types


According to one embodiment, a display device comprises a first substrate, a second substrate opposed to the first substrate and including a first organic film, a first convex portion extending in a first direction, a second convex portion extending in a second direction intersecting the first direction, and a third convex portion aligned with the first convex portion in the second direction and extending in the first direction, and a sealing member located in a second area around a first area in which an image is displayed, wherein the first convex portion, the second convex portion and the third convex portion are located between the first organic film and the sealing member.

Display devices of different types have recently been proposed. A display device includes a display panel formed of a plurality of layers. When an impact or the like is applied to the display panel, a layer whose bonding strength is small is likely to come off from the layers of the display panel.


A device (230, 1330, 1430) includes: a first electrode (232); an electro-statically movable second electrode (234, 1734, 1834); and an electrically insulating layer (233) disposed between the first and second electrodes. The electro-statically movable second electrode is configured to have a first geometric configuration in response to a first electrical potential between the first and second electrodes, and is further configured to have a second geometric configuration in response to a second electrical potential between the first and second electrodes. The device is configured to receive a time-varying voltage and in response thereto the electrostatically movable second electrode is configured to repeatedly transition between the first geometric configuration and the second geometric configuration to influence a flow of a fluid (235) for cooling at least one heat-generating element (310).

Solid state lighting technologies, i.e. illumination based on semiconductor light sources, such as light-emitting diodes (LEDs) and laser diodes, offer a viable alternative to traditional fluorescent, HID, and incandescent lamps. Functional advantages and benefits of LEDs include high energy conversion and optical efficiency, durability, lower operating costs, and many others. Recent advances in LED technology have provided efficient and robust full-spectrum lighting sources that enable a variety of lighting effects in many applications. Some of the fixtures embodying these sources feature a lighting module, including one or more LEDs capable of producing different colors, e.g. red, green, and blue, as well as a processor for independently controlling the output of the LEDs in order to generate a variety of colors and color-changing lighting effects.
In general, light sources including—semiconductor light sources such as LEDs generate heat. There is a persisting need to provide cooling for such light sources, and for various other devices such as other electronics, computers, etc. For this purpose, it is known to provide passive cooling by heat spreaders and/or heat sinks and active cooling by means of fans. However, fans are rather large and heavy, may produce noise, have poor cooling efficiency and have reliability issues. It is also known to provide thermoelectric cooling devices which employ the Peltier effect, or employ synthetic jets or piezoblades, for active cooling. However, with present technology it is not possible to provide a thermoelectric cooling device which can simultaneously have low cost and high power efficiency.
Thus, there is a need in the art for active cooling devices and methods which can overcome one or more of the limitations of current active cooling technologies.

Active cooling device with electro-statically moving electrode and method of active cooling with electro-statically moving electrode


The present invention provides an apparatus and method for measuring the angular rotation of a moving body. The apparatus comprises an upper sensor layer, a lower handle layer substantially parallel to the sensor layer, at least one dither frame formed of the upper sensor layer, the frame having a dither axis disposed substantially parallel to the upper sensor layer and the lower handle layer. The apparatus further comprises a first accelerometer formed of the upper sensor layer and having a first force sensing axis perpendicular to the dither axis for producing a first output signal indicative of the acceleration of the moving body along the first force sensing axis, the first accelerometer having a proof mass and at least one flexure connecting the proof mass to the dither frame such that the proof mass can be electrically rotated perpendicular to the dither axis. The apparatus also comprises a second accelerometer formed of the upper sensor layer and having a second force sensing axis perpendicular to the dither axis for producing a second output signal indicative of the acceleration of the moving body along the second force sensing axis, the second accelerometer having a proof mass and at least one flexure connecting the proof mass to the dither frame such that the proof mass can be electrically rotated perpendicular to the dither axis. The dither frame and proof masses have electrodes on an insulating layer for operating the first and second accelerometers and the upper sensor layer has a rate axis perpendicular to each of the first and second force sensing axes and the dither axis, whereby the first and second output signals have a Coriolis component indicative of the angular rotation of the moving body about the rate axis.

1. Technical Field of the Invention
The present invention relates to an apparatus and methods for determining the acceleration and rate of angular rotation of a moving body, and in particular, one which is adapted to be formed, for example through micromachining, from a silicon substrate.
2. Description of the Prior Art
A variety of methods and systems are known for determining the acceleration and rate of angular rotation of a moving body. Such methods and systems have found their way in a diverse range of applications, one of which is military. However, the use of tactical grade inertia measuring units has been limited by their cost to high-priced systems such as military aircraft, missiles, and other special markets. The cost of inertia measuring units is dominated by the expensive discrete gyroscopes and discrete accelerometers and attendant electronics used to drive and convert these signals for use in computer systems.
Other problems with inertial measuring units are high power consumption and large package size. The problems of high power consumption and large package size further limit applications to larger equipment boxes in equipment racks. For example, a hockey puck sized tactical grade navigator is not known in the prior art.
Still other problems with the prior art, discussed below in more detail, include a limitation in rate bias accuracy caused by modulation of the accelerometer due to coupling from the dither motion which causes phase angle sensitivity of the rate data. A further limitation in rate bias accuracy is caused by modulation of the accelerometer due to coupling of external vibration components coupling into the rate data.
Exemplary rate and acceleration sensors, components of such sensors, and methods of forming the same are described in the following patents all of which are assigned to the assignee of this disclosure: U.S. Pat. Nos. 5,005,413; 5,168,756; 5,319,976; 5,331,242; 5,331,854; 5,341,682; 5,367,217; 5,456,110; 5,456,111; 5,557,046; 5,627,314; 6,079,271; 6,098,462; and 6,276,203.
By way of background, the rate of rotation of a moving body about an axis may be determined by mounting an accelerometer on a frame and dithering it, with the accelerometer's sensitive axis and the direction of motion of the frame both normal to the rate axis about which rotation is to be measured. For example, consider a set of orthogonal axes X, Y and Z oriented with respect to the moving body. Periodic movement of the accelerometer along the Y axis of the moving body with its sensitive axis aligned with the Z axis results in the accelerometer experiencing a Coriolis acceleration directed along the Z axis as the moving body rotates about the X axis. A Coriolis acceleration is that perpendicular acceleration developed while the body is moving in a straight line, while the frame on which it is mounted rotates. This Coriolis acceleration acting on the accelerometer is proportional to the velocity of the moving sensor body along the Y axis and its angular rate of rotation about the X axis. An output signal from the accelerometer thus includes a DC or slowly changing component or force signal F representing the linear acceleration of the body along the Z axis, and a periodic component or rotational signal Ω representing the Coriolis acceleration resulting from rotation of the body about the X axis.
The amplitude of that Coriolis component can be produced by vibrating the accelerometer, causing it to dither back and forth along a line perpendicular to the input axis of the accelerometer. Then, if the frame on which the accelerometer is mounted is rotating, the Coriolis acceleration component of the accelerometer's output signal will be increased proportional to the dither velocity. If the dither amplitude and frequency are held constant, then the Coriolis acceleration is proportional to the rotation rate of the frame.
The linear acceleration component and the rotational component representing the Coriolis acceleration may be readily separated by using two accelerometers mounted in back-to-back relationship to each other and processing their output signals using summed difference techniques. In U.S. Pat. No. 4,510,802, assigned to the assignee of the present invention, two accelerometers are mounted upon a parallelogram with their input axes pointing in opposite directions. An electromagnetic D'Arsonval coil is mounted on one side of the parallelogram structure and is energized with a periodically varying current to vibrate the accelerometers back and forth in a direction substantially normal to their sensitive or input axes. The coil causes the parallelogram structure to vibrate, dithering the accelerometers back and forth. By taking the difference between the two accelerometer outputs, the linear components of acceleration are summed. By taking the sum of the two outputs, the linear components cancel and only the Coriolis or rotational components remain.
U.S. Pat. No. 4,590,801, commonly assigned to the assignee of the present invention, describes the processing of the output signals of two accelerometers mounted for periodic, dithering motion to obtain the rotational rate signal Ω and the force or acceleration signal F representing the change in velocity, i.e. acceleration, of the moving body along the Z axis.
U.S. Pat. No. 4,510,802, commonly assigned to the assignee of the present invention, describes a control pulse generator, which generates and applies a sinusoidal signal of a frequency ω to the D'Arsonval coil to vibrate the parallelogram structure and thus the first and second accelerometer structures mounted thereon, with a dithering motion of the same frequency ω. The accelerometer output signals are applied to a processing circuit, which sums the accelerometer output signals to reinforce the linear components indicative of acceleration. The linear components are integrated over the time period T of the frequency ω corresponding to the dither frequency to provide the force signal F, which represents the change in velocity, i.e., acceleration, along the Z axis. The accelerometer output signals are also summed, whereby their linear components cancel and their Coriolis components are reinforced to provide a signal indicative of frame rotation. That difference signal is multiplied by a zero mean periodic function sgnc (ωt). The resulting signal is integrated over a period T of the frequency (ω by a sample and hold circuit to provide the signal Ω representing the rate of rotation of the frame.
The D'Arsonval coil is driven by a sinusoidal signal of the same frequency ω which corresponded to the period T in which the linear acceleration and Coriolis component signals were integrated. In particular, the pulse generator applies a series of pulses at the frequency ω to a sine wave generator, which produces the substantially sinusoidal voltage signal to be applied to the D'Arsonval coil. A pair of pick-off coils produce a feedback signal indicative of the motion imparted to the accelerometers. That feedback signal is summed with the input sinusoidal voltage by a summing junction, whose output is applied to a high gain amplifier. The output of that amplifier, in turn, is applied to the D'Arsonval type drive coil. The torque output of the D'Arsonval coil interacts with the dynamics of the parallelogram structure to produce the vibrating or dither motion. In accordance with a well known in the art servo theory, the gain of the amplifier is set high so that the voltage applied to the summing junction and the feedback voltage are forced to be substantially equal and the motion of the mechanism will substantially follow the drive voltage applied to the summing junction.
U.S. Pat. No. 4,881,408 describes the use of vibrating beam force transducers in accelerometers. In U.S. Pat. No. 4,372,173, the force transducer takes the form of a double-ended tuning fork fabricated from crystalline quartz. The transducer comprises a pair of side-by-side beams which are connected to common mounting structures at their ends. Electrodes are deposited on the beams and a drive circuit applies a periodic voltage signal to the electrodes, causing the beams to vibrate toward and away from one another, 180 degrees out of phase. In effect, the drive circuit and beams form an oscillator with the beams playing the role of a frequency controlled crystal, i.e., the mechanical resonance of the beams controls the oscillation frequency. The vibrating beams are made of crystalline quartz, which has piezoelectric properties. Application of periodic drive voltages to such beams cause them to vibrate toward and away from one another, 180 degrees out of phase. When the beams are subjected to accelerating forces, the frequency of the mechanical resonance of the beams changes, which results in a corresponding change in the frequency of the drive signal. When subjected to acceleration forces that cause the beams to be placed in tension, the resonance frequency of the beams and thus the frequency of the drive signal increases. Conversely, if the beams are placed in a compression by the acceleration forces, the resonance frequency of the beams and the frequency of the drive signal is decreased.
Above referenced U.S. Pat. No. 5,005,413 describes accelerometers utilizing vibrating force transducers that require materials with low internal damping to achieve high Q values that result in low drive power, low self-heating and insensitivity to electronic component variations. Transducer materials for high-accuracy instruments also require extreme mechanical stability over extended cycles at high stress levels. Crystalline silicon possesses high Q values, and with the advent of low cost, micromachined mechanical structures fabricated from crystalline silicon, it is practical and desirable to create vibrating beams from a silicon substrate. Commonly assigned U.S. Pat. No. 4,912,990 describes a vibrating beam structure fabricated from crystalline silicon and including an electric circuit for applying a drive signal or current along a current path that extends in a first direction along a first beam and in a second, opposite direction along a second beam parallel to the first. A magnetic field is generated that intersects substantially perpendicular the conductive path, whereby the first and second beams are caused to vibrate towards and away from one another, 180 degrees out of phase.
Digital techniques employ stable, high frequency crystal clocks to measure a frequency change as an indication of acceleration forces applied to such vibrating beam accelerometers. To ensure precise integration or cosine demodulation, a crystal clock is used to set precisely the frequency of the dither drive signal. Outputs from two accelerometers are fed into counters to be compared to a reference clock signal produced by the crystal clock. A microprocessor reads the counters and processes the data to provide a force signal F and a rotational signal Ω. The main advantage of digital processing is the ability to demodulate with extreme precision. The short term stability of the reference crystal clock allows the half cycle time basis to be precisely equal. Thus, a constant input to the cosine demodulator is divided up into equal, positive half cycle and negative half cycle values, whose sum is exactly zero.
In an illustrative embodiment, the two accelerometer signals are counted in their respective counters over a 100 Hz period (corresponding to 100 Hz of the dither frequency ω) and are sampled at a 400 Hz data rate corresponding to each quarter cycle of the dither motion. The two accumulated counts are subtracted to form the force signal F. Since the counters act as an integrator, the acceleration signal is changed directly to a velocity signal. Taking the difference of the acceleration signals tends to reject all Coriolis signals as does the counter integration and locked period data sampling.
The Coriolis signals are detected by a cosine demodulation. The cosine demodulated signals from the first and second accelerometers are summed to produce the Δθ signal. Again, the counters integrate the rate data to produce an angle change. The sum also eliminates any linear acceleration and the demodulation cancels any bias source including bias operating frequency and accelerometer bias. The accelerometer temperature is used in a polynomial model to provide compensation for all the coefficients used to convert the frequency counts into output units. Thus, the scale factor, bias and misalignment of the sensor axes are corrected over the entire temperature range.
The demodulation of the frequency sample is straightforward once the data is gathered each quarter cycle. The cosine demodulation is simply the difference between the appropriate half cycles. The linear acceleration is the sum of all samples.
Various issues with the use of vibrating beam force transducers in accelerometers include the need to operate the device in a substantial vacuum such that the beams can vibrate at their natural frequency without loss of energy from viscous damping. Also, the vibrating beams of the first and second accelerometers are formed in first and second layers of epitaxial material formed on opposing sides of the silicon substrate so that the force sensing axis of each accelerometer is directed opposite to the direction of the other. In other words, the vibrating beams must be on opposing sides of the substrate so that one will be in compression and the other in tension when subjected to an applied acceleration force. The high doping levels in the epitaxial layer required to form the vibrating beams make the material inherently unstable. Thus, the output of the vibrating beams tends to degrade over time and with exposure to thermal environments. The nature of vibrating beam transducers causes accelerometer design and analysis to be relatively complex as compared to that of simpler force rebalance accelerometers and their larger size reduces the quantity of accelerometers which can be fabricated in a single wafer of silicon substrate so that vibrating beam accelerometers are inherently more expensive to produce than miniature force rebalance accelerometers.
Miniature silicon force-rebalance accelerometers in an integrated circuit form are small and inexpensive and generally have a large dynamic range and are operable in high vibration environments over a wide temperature range. Miniature silicon force-rebalance accelerometers having a silicon proof mass suspended between a pair of electrode layers and responsive to differential capacitive coupling between the electrode layers and the proof mass for opposing acceleration forces applied to the proof mass are described in U.S. Pat. No. 4,336,718. The miniature silicon force-rebalance accelerometer of the prior art includes a proof mass and two flexures integrally formed from a silicon substrate. The flexure preferably defines a bend line along the mid-plane of the proof mass which is intended to minimize vibration rectification. The silicon substrate including the proof mass is anodically bonded between upper and lower glass substrates having upper and lower metal, for example, gold, electrodes deposited thereon. The upper and lower substrates are preferably formed identically. Symmetry between opposing surfaces of the proof mass and between opposing the electrodes deposited on the upper and lower glass substrates surfaces minimizes bias and maximizes dynamic range and linearity.
The state of the art in micromachined rate and acceleration sensors is represented by U.S. Pat. No. 5,341,682 which is commonly assigned to the assignee of the present invention and incorporated herein by reference. Rate and acceleration sensors, as disclosed in U.S. Pat. No. 5,341,682, are comprised of two accelerometers aligned in a single plane such that the input or sensitive axes of the two accelerometers are parallel and the output or hinge axes of the two accelerometers are parallel. The two accelerometers are vibrated or dithered at a predetermined frequency along a dither axis parallel to the hinge axes. The two accelerometers tend to vibrate at slightly different frequencies due to slight mass mismatch. Even if driven by a drive signal of common frequency, the accelerometer motions tend to be out of phase with each other. A link is connected to each of the two accelerometers whereby motion imparted to one accelerometer results in like, but opposite motion imparted to the other accelerometer. Thus, the dithering motion imparted to one accelerometer is ideally of the exact same frequency and precisely 180 degrees out of phase with that applied to the other accelerometer.
The link provides an interconnect between the two accelerometers which is stiff in the dither axis such that the motion imparted to one accelerometer is effectively transmitted to the other accelerometer and both accelerometers ideally dither at the same frequency and precisely 180 degrees out of phase. The link is pivotally fixed to the frame by a pivot flexure. The link is further connected to each of the two accelerometers by flexures. The link is typically formed in a complex asymmetric shape. The complexity of the link is driven by practical considerations involved in adapting the link to accommodate both, the pivot flexure and the two link-to-accelerometer flexures. The link's complex asymmetric shape provides adequate clearance between the link and the frame for the pivot flexure. The link's shape also provides adequate clearance between the link and each accelerometer to provide the precise flexure length to ensure that the flexures exhibit a predetermined mix of simple arc bending and "S-bend" motion and to ensure that any motion imparted to one accelerometer by the flexures is imparted to the other accelerometer as a sinusoidal function without introducing a higher order harmonic into the translation motion.
Although the device described in above referenced U.S. Pat. No. 5,341,682 functions for the purposes intended, its exact behavior is difficult to predict and/or model analytically. For example, the complex shape of prior links results in spring rates which are asymmetrical and a shape which is difficult to solve analytically. Additionally, constructing the shape previously taught results in flexures whose thicknesses and hence vibration properties are difficult to control. Therefore, later patents, for example, U.S. Pat. No. 6,098,462 and U.S. Pat. No. 6,079,271, provide links having simple geometric shapes formed symmetrically about the pivot point. The behavior of these simpler symmetric links is more easily predicted and/or modeled analytically. For example, these simpler symmetric links result in spring rates which are symmetrical and easier to solve analytically using conventional methods. Additionally, constructing the simpler symmetric shape results in flexures whose thicknesses and hence vibration properties are more easily controlled.
U.S. Pat. No. 6,098,462, which is commonly assigned to the assignee of the present invention, provides a linkage between accelerometers in a micromachined rate and acceleration sensor which is relatively simple to solve analytically and results in flexures whose thicknesses are relatively insensitive to process variations. For example, the link shape can be solved using classical mechanical equations. In addition, the U.S. Pat. No. 6,098,462 provides a simple symmetrically shaped link, which is relatively insensitive to process variations, having sufficient mechanical stiffness to effectively transmit motion imparted to one accelerometer to the other accelerometer such that both accelerometers dither at the same frequency and precisely 180 degrees out of phase. The simple symmetrical link provides adequate clearance between the link and each accelerometer for flexures having a length which ensures that the flexures exhibit a predetermined mix of simple arc bending and "S-bend" motion and which ensures that any motion imparted to one accelerometer by the flexures is imparted to the other accelerometer as a sinusoidal function without introducing a higher order harmonic into the translation motion. The link having a columnar shape in the dither cross-axis has a reduced sensitivity to cross-axis vibration.
As described in U.S. Pat. No. 5,341,682, the accelerometers are suspended from a dither or mounting frame by a pair of flexures or "dither legs" which vibrate upon application of a dithering force to translate the accelerometers in a predominantly linear relationship with each other. However, true orthogonality is not achieved between the dither motion and the Coriolis acceleration sensing direction in the normal manufacturing process. State of the art micromachined vibrating Coriolis rate and acceleration sensors, as represented by U.S. Pat. No. 5,341,682 and others of the above incorporated patents, experience quadrature motion due to the manifold sources of mechanical imperfection resulting from the tolerances inherent in manufacturing processes. This axis misalignment in conjunction with a phase shift causes a rate bias error which limits performance.
One method and apparatus for overcoming the errors introduced by quadrature motion is described in U.S. Pat. No. 5,886,259, assigned to the assignee of the present invention, steers the accelerometer input axes to be orthogonal using capacitive attraction between the sensing mass and stationary members of the sensor frame. However, such capacitive steering requires very small gaps, on the order of microns, between the sensing mass and stationary members to generate sufficient applied force. Given the very small gaps necessary, actual implementation of this axis alignment feature is difficult in a normal manufacturing setting using conventional processing methods.
The prior art as discussed above, however, has proven unsatisfactory. Generally, the Coriolis rate sensors have the problem of difficult fabrication, lengthy analysis and hard to implement axis-alignment capability. The result of such shortcomings is less than optimal yields, low quantity of sensors per wafer, higher design costs and limited rate bias performance.
Accordingly, it is clear that there exists a need for a cost effective method and apparatus for determining the acceleration and rate of angular rotation of a moving body which overcomes the above mentioned problems.