A common channel signal extraction/insertion device for a multiplexed digital transmission system includes a common channel signal insertion/extraction circuit instead of time switches. The common channel signal insertion/extraction circuit includes: a receiver-side speed converter memory 51A for buffering the multiplexed signal 13 received from the multiplexer circuit 3; and a transmitter-side speed converter memory 52A for buffering the common channel signals received from the common channel signal controller 7. The high-speed and the low-speed side reading and writing operations are controlled by the high-speed side controller 51C and the low-speed side controller 51D, respectively. The selector 53 selects between the common channel signals read out from the transmitter-side speed converter memory 52A and the data supplied from the digital switching channel 6, thereby obtaining the multiplexed signal 13a and outputting it to the demultiplexer 12.

This invention relates to common channel signalling insertion/extraction devices using high-speed digital multiplexers.
FIG. 7 shows a conventional common channel signalling insertion/extraction device disclosed in Japanese Laid-Open Patent (Kokai) No. 60-153697. The digital signals 1 for a plurality of dedicated digital signal lines are terminated at digital terminals DTI.sub.1 -DTI.sub.n 2, each consisting of a modulator/demodulator, a frame synchronizer, a frame alignment and detection circuits for various alarm signals for the dedicated digital signal lines. The outputs from the digital terminals DTI.sub.1 -DTI.sub.n 2 are supplied to a multiplexer circuit 3 for multiplexing the digital signals 1. Thus, if there are four digital signal lines at 1.5 Mbps, a signal at more than 6 Mbps multiplexing the four digital signals are output from the multiplexer circuit 3.
The multiplexed signal from the multiplexer circuit 3 is supplied to the receiver side time switch 10a of the receiver/transmitter time switch 10, such that the data portions thereof are separated from the common channel signalling portions. The data and the common channel signals thus separated from each other are input to the digital switching channel 6 and the common channel signalling controller 7, respectively. The outputs of the digital switching channel 6 and the common channel signalling controller 7 are supplied to the transmitter side time switch 10b of receiver/transmitter time switch 10, where the data and the common channel signals are multiplexed. The multiplexed signal from the transmitter side time switch 10b is demultiplexed by the demultiplexer 12 and the resulting separate digital signals are output to the dedicated digital lines via the digital terminals DTI.sub.1 -DTI.sub.n 2.
The receiver side time switch 10a receives the multiplexed signal from the multiplexer circuit 3 and separates one or more common channel signals at 64 Kbps from data portions. Conversely, the transmitter side time switch 10b inserts one or more common channel signals at 64 Kbps at a plurality of predetermined positions of the multiplexed signal. The demultiplexer 12 demultiplexes and branches the signal to the dedicated digital lines via the digital terminals DTI.sub.1 -DTI.sub.n 2.
The common channel signalling controller 7 receives the common channel signalling at 64 Kbps from the receiver side time switch 10a and effects functions such as: the error correction of the data, the establishment of data link with the opposite communicating party, assembly of the data structure, and decoding of the signals within frames. The resulting output of the common channel signalling controller 7 is supplied to the switch controller 8, which is supplied with the data from the digital switching channel 6. The switch controller 8 supplies the data transmitted to the opposite communicating party to the common channel signalling controller 7. In response thereto, the common channel signalling controller 7 assembles the data transmitted to the opposite party, establishes the data link therewith, and outputs the common channel signalling at 64 Kbps to the transmitter side time switch 10b.
The above conventional common channel signalling insertion/extraction device has the following disadvantage. When the capacity of the device is enlarged (for example, when high-speed dedicated digital lines are accommodated or when the multiplexed number of dedicated digital lines are increased), the data transmission rate from the multiplexer circuit 3 to the receiver/transmitter time switch 10 and from the receiver/transmitter time switch 10 to the demultiplexer 12 increases. Thus, the processing speed of the receiver/transmitter time switch 10 should also be increased. Within the receiver side time switch 10a, however, the data and the common channel signals are processed by the same circuit. Thus the reading-out and the writing-out rates of the common channel signals increase accordingly. A common channel signalling controller 7 which can respond to the high-speed input/output becomes necessary.
If such a common channel signalling controller 7 is implemented with the ICs and LSIs that are commercially available, the device becomes expensive, or the number of supported channels must be reduced. Further, since the common channel signals and the data are processed by the same circuit of the receiver/transmitter time switch 10, the failure of the receiver/transmitter time switch 10 directly affects the processing of the common channel signals.

Common channel signal extraction/insertion device


A pixel circuit, a display panel and a driving method. The pixel circuit includes a first light-emitting circuit, a first drive circuit, a first compensating circuit, a first data write circuit, a first reset circuit, a first storage circuit, a first initializing circuit, a first light-emitting control circuit, a second light-emitting circuit, a second drive circuit, a second compensating circuit, a second data write circuit, a second reset circuit, a second storage circuit, a second initializing circuit, a second light-emitting control circuit, a third light-emitting circuit, a third light-emitting control circuit, a third drive circuit, and a third initializing circuit.

Organic light-emitting diode (OLED) display panels have wide development prospective in the display field due to the characteristics of autoluminescence, high contrast, low thickness, wide viewing angle, rapid response speed, capability of being applied to flexible panels, wide service temperature range, simple production, etc.
Due to the above characteristics, an OLED display panel may be applied to a device with display function such as a mobile phone, a display, a notebook computer, a digital camera, an instrument or the like.

Pixel circuit having third drive circuit connected to first drive circuit and second drive circuit respectively, display panel and driving method

CHENGDU BOE OPTOELECTRONICS TECHNOLOGY CO., LTD.


A standing wave detection method, a standing wave detection apparatus, and a base station are disclosed. The method includes collecting, a feedback signal from a feedback path of a base station which uses a baseband multi-tone signal as a transmission signal; performing calibration on the feedback signal by using stored calibration data to obtain a reflected signal in the feedback signal; and obtaining a standing wave detection value according to the transmission signal and the reflected signal that is in the feedback signal.

In the field of wireless communication technologies, for a wireless communication product such as a base station and so on, product quality needs to be inspected through standing wave detection to ensure signal quality in a communication process.
In the prior art, the standing wave detection is implemented through a frequency domain reflectometry (FDR) method or a phase-detection frequency-domain reflectometry (PDFDR) method. The FDR is also referred to as a frequency sweeping reflectometry, and is configured to send a continuous stepped sine wave, receive a stepped continuous wave reflected by discontinuous points after discontinuous reflection via a transmission cable, and performs processing and analysis by detecting a difference between a transmission signal and a feedback signal, to obtain a standing wave ratio and fault location information. FIG. 1 is a schematic diagram of a PDFDR method. As shown in FIG. 1, the base station sends a frequency sweep signal, distinguishes an incident wave from a reflected wave through a directional coupler, and compares a difference (equivalent to a delay) between the incident wave and the reflected wave. An obtained simulated voltage sequence undergoes inverse fast Fourier transform (IFFT), and a location of a reflection point and strength of the feedback signal are obtained, that is, a connection state and a fault state of an antenna feeder cable are obtained.
In the prior art, an additional hardware circuit such as a coupler, a load, a frequency mixer, an operation amplifier, an analog-to-digital converter (ADC) and so on need to be added to the standing wave detection, which leads to a complicated link and a high cost.

Standing wave detection method, standing wave detection apparatus and base station


A screw pump having a pair of screw rotors meshed with each other and rotatably supported in a housing having an intake port provided at one end and a piston movably provided at the other axial end of the housing, which piston defines a discharge port in cooperation with the housing. The movement of the piston in a direction substantially perpendicular to the axes of the screw rotors enables the distance between a discharge starting position of the discharge port and the intake port to be varied, so that the internal compression ratio can be varied. This arrangement ensures that the size of the housing will not be increased and any disadvantage due to the difference in thermal expansion along the length of the housing can be overcome.

1. Field of the Invention
The field of the present invention is screw type pumps, such as mechanical superchargers, having a pair of screw rotors meshed with each other and rotatably supported in a housing, and particularly, screw type pumps with a variable internal compression ratio.
2. Description of the Prior Art
Screw type pumps with a variable internal compression ratio are already known, for example, from Japanese Utility Model Application Laid-open No. 46435/89 and Japanese Utility Model Publication No. 40727/78.
In a mechanical supercharger in the form of a screw type pump that is disclosed in Japanese Utility Model Application Laid-open No.46435/89, a slide valve movable axially of the screw rotors is provided in the housing, so that the internal compression ratio is varied by driving the slide valve. Because the slide valve is moved axially, however, the size of the housing is increased by the range of such movement. Moreover, in a mechanical supercharger using screw rotors, the temperature varies in the axial direction of the supercharger. Therefore, in a structure in which the slide valve is moved in the axial direction, a difference in clearance between the slide valve and the housing is produced in such axial direction due to a difference in thermal expansion depending upon the variation of temperature, thereby making reliable sealing difficult.
In a supercharger in the form of the screw type pump disclosed in the above-identified Japanese Utility Model Publication No.40727/78, a portion of the intake gas is circulated by controlling an opening provided in the side of a housing for opening and closing thereof and therefore, a reduction in efficiency occurs.


Devices and methods for forming a device are disclosed. A transistor is formed on the substrate. The transistor includes a gate, a source and a drain. An insulation layer is formed on the substrate. The insulation layer is partially disposed on the gate and a sidewall of the gate. The drain is offset from the gate by the insulation layer. An overlayer is formed on the substrate covering the transistor and insulation layer. A field plate in the form of a field plate contact is formed in the overlayer. The field plate contact is disposed on and coupled to the insulation layer for mitigating the formation of electric field adjacent to drain side of the gate.

A foundry based Bipolar-CMOS-DMOS (BCD) technology typically includes a full suite of devices having a wide range of operation voltages. For example, in a 180 nm BCD platform, operation voltages such as 1.8V, 5V, 10V, 12V, 16V, 20V, 24V and 30V are provided to satisfy different applications in automotive, audio, display, etc.
Depending on the BCD operation platforms, the various devices are typically categorized according to their operational voltage. By way of an example, devices operate in the relatively higher voltage range, e.g., 24V and above, may be referred to as the high voltage (HV) devices. Such HV devices include laterally diffused metal oxide semiconductor (LDMOS) transistors. Devices operate in the relatively lower voltage range, e.g., low as 1.8V/5V, may be referred to as the low voltage (LV) devices, such as the complementary metal-oxide-semiconductor (CMOS) transistors. Devices which fall between the higher and lower voltage ranges may be referred to as the intermediate/medium voltage (MV) devices, e.g., 10V to 20V. An example of the MV devices is the extended drain MOS (EDMOS) transistor.
Two types of doped wells, namely the LV doped well and HV doped well, are usually provided for the devices, taking into considerations of the cost effectiveness. Typically, performance of the HV and LV devices can be directly optimized by utilizing the aforementioned doped wells. For example, a HV doped well is typically provided for optimizing the performance of HV devices and a LV doped well for the LV devices. However, optimizing MV devices can only be relied on the device structure designs.
The present disclosure provides a structure design which optimizes the performance of a MV device and a method for forming such a MV device.

Extended drain metal-oxide-semiconductor transistor


The device of the present invention is a locking quick release device for allowing quick and easy release and adjustment to a bicycle seat and/or bicycle wheels, while still allowing the seat and/or wheels to lock to the bike frame when the quick release lever is in the closed position. The device includes a standard plug lock combined with the lever of the quick release device. In the closed position, the lock can be engaged with a key, securely locking the lever closed and the seat and/or the wheels to the bicycle frame.

The present invention relates to locks for quick release mechanisms. More particularly, the invention relates to a lock that attaches to the lever assembly of quick release mechanisms for bicycle seat posts, bicycle wheels, and bicycle carriers.
Bicycles are provided with quick release mechanisms for the seat post and wheels which allow for the quick and easy removal and adjustment without the use of tools. Frequently, these components are removed during transport of the bicycles. A conventional type of quick release includes a hand-operated lever which controls a cam shaft for releasing and securing the seat to the frame, or the wheels to the fork of the bicycle.
These lever-actuated quick release systems ease the chore of adjusting and removing the wheels and seats from the bicycle; however, they also ease the task of the thief in removing the seat or wheels. As a consequence, to prevent theft, it has become rather ordinary for the bicyclist to remove the wheel and the seat, usually the front wheel, and then lock the front and back wheels with the bicycle to some permanently fixed post or the like. The seat, which is difficult to lock with the wheels, is generally carried with the bicyclist. Upon return the bicyclist must then reassemble his or her bicycle before proceeding. This practice is extremely inconvenient for the rider.
Several prior art locking devices exist for quick release mechanisms. One such combination locking device and quick release mechanism is described in U.S. Pat. No. 5,291,763. In this device, the lock includes a conventional key operated plug lock mounted within a lock adaptor which in turn is rotatably mounted upon a lever housing. The lever housing includes an aperture for attachment of the conventional lever bore at the end of the shaft of the quick release mechanism. A camming mechanism with stop points is used to control rotation of the lock adaptor on the lever housing. In the locked position, the lever housing blocks movement of the lever arm. One problem with this design is that the lever can still be moved a short distance before it is stopped by the lever housing. The lock adapter also adds weight to the bicycle which is undesirable for most riders.
Another such combination locking device and quick release mechanism is described in U.S. Pat. No. 4,028,915. The device includes a lockable housing and cover which prevents operation of the lever. The housing and cover must be removed from the device to operate the lever. One problem with this design is that the housing may be lost when removed.
One other prior art quick release mechanism and integral lock is described in U.S. Pat. No. 4,621,873 to Weinstein et al. The device includes a conventional lock and a spring operated pin. In the locked position, the pin is engaged within a hole formed in the lever arm to prevent operation of the lever. The problem with this device is that the lever needs to be in precisely the right position for the pin to become engaged with the hole in the lever arm. This alignment may be difficult to achieve.
Therefore there is a need in the art for a locking quick release device that does not allow the lever to move any distance in the locked position, that does not require removal to operate the quick release mechanism, and that is small and light weight to enable the rider to leave the lock on the quick release while riding the bicycle.
An object of this invention is to completely deter the casual thief from stealing and greatly deter a professional thief from stealing bicycle seats and wheels.
Another object of this invention is to provide a lock for the mechanism that allows quick and easy release and adjustment to a bicycle seat and/or bicycle wheels without using any tools.
Another object of the present invention is to provide a small, simple, inexpensive and light weight universal lock for a quick release mechanism.
Yet another object of this invention is to allow the lock to be universal in that it can be keyed the same as other locks used by the rider, so that the rider only has to have one key for all his/her cycling related locks.


A method and apparatus for determining a type of solution and the concention of that solution by acoustic means. Generally stated, the method consists of: immersing a sound focusing transducer within a first liquid filled container; locating a separately contained specimen solution at a sound focal point within the first container; locating a sound probe adjacent to the specimen, generating a variable intensity sound signal from the transducer; measuring fundamental and multiple harmonic sound signal amplitudes; and then comparing a plot of a specimen sound response with a known solution sound response, thereby determining the solution type and concentration.

The ability to measure solute concentration using aspects of nonlinear acoustic propagation, given a knowledge of which solvent and solute is present, and in some cases to distinguish qualitatively among known solvent/solute systems, has already been established in the relevant literature. However, the ability to do both qualitative and quantitative measurements simultaneously and to include more than one solvent/solute system in the analysis by these techniques does not currently exist.
Propagation of sound in solvents and their solutions has long been known to be nonlinear. The nonlinearity is manifested in the generation of harmonics and in velocity-dependent dispersion. The degree of nonlinearity is a function of the intensity of the sound wave. The degree of nonlinearity is also a function of the specific, detailed interactions among solvent and solute molecules, and under some conditions can be used to identify solvents and solutes. The degree of nonlinearity is conventionally expressed as the value of the parameter B/A, where A and B are the constants in the first two terms in a perturbative power-series expansion for the nonlinear strength.
Considerable current research has been directed toward medical applications of this phenomenon as a diagnostic tool. As a simple example, diseased organs often have a different water (and solute) content from healthy organs. More sophisticated applications-oriented research addresses identification of specific organic compounds. Spatial imaging of the sources of nonlinearity has also been done and these images reveal bone, blood vessels, and muscle distinctly because of differences in nonlinearity. Nearly all of the current work in the field is being done at "physiological" sound intensities. These intensities are characteristic of conventional medical ultrasound imaging, and are sufficiently low as to preclude injury to tissues.
Since the degree of nonlinearity is itself a function of acoustic intensity, it is to be expected on general principles that higher acoustic intensities will increase the resolution of small differences among solvent/solute systems, and that higher intensities may reveal additional aspects of the nonlinear interactions between solvent and solute.
The limiting sound intensities are dictated by solution cavitation, where the solute and solvent molecules are effectively torn apart. This phenomenon is used routinely, for example, in ultrasonic cleaners, and in certain techniques to modify equilibria in chemical reactions.
Applications of nonlinear phenomena as a measurement tool are different in principle from the current generation of acoustic chemical-sensing instrumentation which uses the speed of sound and related parameters to do chemical analysis for assessment of chemical agents in artillery shells and for arms control verification purposes. Measurement of the speed of sound with sufficient accuracy to quantify the small differences between solvent/solute systems requires knowledge of a precisely-known flight path. Manufacturing tolerances among similar containers are usually found to be large enough to introduce significant ambiguity into the measurement.
Current nonlinear-propagation and speed-of-sound methods produce ambiguous results with completely unknown solutions primarily because they yield only one parameter, the nonlinear strength parameter previously mentioned, B/A, or the speed of sound, neither of which are unique to the solution. Almost any solution can be simulated to give the same speed of sound or B/A by the properties of various mixtures of different solutions.
A series of experiments have been previously performed by the present inventor to provide background information relating to measurements of changes in the speed of sound in dilute solutions as a function of the molar concentration.
The experimental apparatus used consisted of a container, a piezoelectric transducer and solution specimen in bottles. A sharp pulse of ultrasonic energy at 5 MHZ is generated by the piezoelectric transducer within the container. The container also contains three annular target rings at fixed distances from the transducer to provide pulse/echo targets which define transit time. The time-of-flight is measured by digital means as the interval between the echoes from the target rings.
The full waveform is recorded by an analog-to-digital converter. The time interval between target-ring echoes is measured with a digital phase-matching technique that has a resolution approaching 100 picoseconds.
Solutions for experiments were prepared in half-decade steps in concentration from 5.times.10.sup.-4 Molar (M) to 1.0M for NaCl, NaI, CsCl, and CsI, in two series. One series started at 1.0M, and the other at 0.5M.
The largest competing effect is that of temperature, which also changes the speed of sound in the solution. The temperature of the solutions was maintained constant at about 31.degree. C.
The time of flight as measured was an accurately linear function of concentration over almost the full range measured in all solutes as seen in FIGS. 1 and 2. These are linear plots covering more than four decades in concentration of NaCl and CsCl respectively. The time scale on the ordinate is the transit time in this particular apparatus. The zero-concentration intercept is the transit time for water.
The slope of the transit-time vs. concentration is the calibration for the solute in each case, in units of .mu.s/M for this apparatus. The slope and intercept were computed by the method of least-squares, weighted according to the experimental uncertainty at each point. Results are given in Table 1 and are plotted in FIGS. 1 and 2 for NaCl and CsCl, respectively.
TABLE 1 ______________________________________ Measured Calibration Slopes Solute Slope (.mu.s/M) ______________________________________ NaCl -6.7524 CsCl 0.1219 NaI 2.6577 CsI 25.6011 ______________________________________
The calibration for NaCl has a negative slope; the speed of sound increases as the concentration gets larger, at least up to 0.5M. The other solutes have increasingly positive calibrations. The slope for CsCl is small, but positive and easily measured with precision, as can be seen in FIG. 2.
The calibrations are shown in FIG. 3, relative to the time-of-flight for demineralized water, so that they apply to any container length.
The speed of sound in any medium is a function of the average intermolecular forces in that medium and of the mass of the individual particles involved. Solutes in a liquid change the intermolecular forces, which determine the sound speed. This work shows that, for very dilute solutions at least, the changes in intermolecular forces for a given low concentration solute are proportional to solute concentration in all cases investigated.
In a polar liquid, it can be expected that molecular or ion size, charge, hydration spheres, and similar variables also affect the intermolecular forces which control the speed of sound. Introductory texts generally state that the speed of sound is inversely proportional to the square root of the density, which is true in most cases. It is clearly not true here, however, since the density of the solution, proportional to the molecular weight in these measurements, clearly is not dominant, otherwise the calibration for NaCl could not be negative.
Consequently, the calibrations of FIG. 3 can be used directly and on-line for precise quantitative analysis of solutions of a single known solute and the difference in calibration slopes of FIG. 3 indicates that the technique can be also used for qualitative analysis as well.
Experiments in the field of solutions suggest that the nonlinearity mechanism involves hydration. Molecules in water solution can be described as being surrounded by hydration spheres of water molecules in "layers" or shells, the inner layer being most tightly bound, and other layers successively less well bound. The number and binding energy of water molecules in each layer is a function of solute molecule size, binding mechanism (e.g., electrostatic, Van Der Walls, etc.) and other parameters. The configuration and binding energies of the hydration sphere are unique properties of each solute molecule in each of its solvents, for many practical purposes at least. Liquids in general and pure solvent molecules in particular can be described as having the same structure, with each molecule being surrounded by an ordered array of other solvent molecules, the array becoming more disordered with distance, whether or not there are any solutes. Fully equivalent types of interactions affect other solvent systems, including, specifically, organic solvents.
To develop this theory of hydration and to explain the origin of nonlinear propagation, consider that an intense sound wave is propagating in a solution. During each compressive half-cycle of the sound wave, the solute, or solvent, molecule and all of its potential hydration sphere will be packed tightly together; the sound wave will be moving relatively heavy entities consisting of the solvent molecule and its hydration sphere, as it propagates. During each tensile half-cycle of the sound wave the tensile forces will strip off all or part of one or more hydration layers, depending on sound intensity, configuration, and binding energy of hydration layers. The sound wave will be moving relatively lighter entities during this part of the cycle.
Any harmonic motion in which the moving mass changes each half-cycle will generate harmonics, which is to say, is nonlinear. It is hypothesized that this is the mechanism for nonlinearity generation in solvents and their solutions.
One of the consequences of this hypothesis is that one expects the rate of nonlinearity generation with increasing intensity to change as the acoustic intensity becomes sufficient to strip all or part of each layer from the hydration sphere. Eventually the nonlinearity should stop increasing when there are no more layers to strip off, and this should happen at intensities lower than cavitation. At intermediate energies, any process which systematically changes the degree of hydration, such as complete removal of a hydration layer, will lower the rate of increase of nonlinearity with increasing acoustic intensity. Both complete and partial removal of the hydration sphere are termed "saturation" as described later.

Method for chemically analyzing a solution by acoustic means

The United States of America as represented by the Department of Energy


Disclosed is a burner head capable of securing heat resistance and durability characteristics and improving the quality of machining at the same time, capable of easily and stably machining a material into a complicated shape. A second metal primary material of the iron family having high workability and first metal primary materials of the SUS family having high heat resistance are rolled out. Their side plate ends are butt-welded by laser to form a one-piece metal flat-plate material. A press molding machine is operated to press mold recessed portions of a pair of plate members simultaneously with cutting along a contour line. Then, folding is carried out, and they are closely joined together. A gas passage is formed by a recessed portion of the second metal primary material section. A burner port is formed by a recessed portion of the first metal primary material section.

1. Field of the Invention
The present invention generally relates to a burner head for use in gas burning appliances such as water heaters, combustion equipment, et cetera. This invention relates more particularly to a burner head formed by joining together press-molded metal plate materials.
2. Description of the Related Art
It is well known in the prior art to form a burner head for use in gas burning appliances, first by superimposing inner and outer plates to be disposed interiorly and then by joining together the plates to a unit by means of spot welding or laser welding from the side (see Japanese Patent laid open Gazette No. 7(1995)-158822). More specifically, the inner and outer plates are each formed by press molding a sheet of metal material plate and the thus press-molded metal material plates are placed one over the other and are assembled together. Thereafter, the plates are welded together in the way as described above.

Burner head and gas burning appliance provided with such a burner head


A vacuum vessel has a member to be cooled to a low operating temperature inside the vacuum vessel and a main cooling circuit having fluid for cooling the member to operating temperature. The main cooling circuit has first fluid refrigerating means located at the vacuum vessel. To achieve rapid cooling, there is a pre-cooling circuit having the fluid for pre-cooling the member towards the operating temperature. The pre-cooling circuit has second fluid refrigerating means operating independently of the first fluid refrigerating means. The pre-cooling circuit cools the main cooling circuit, prior to operation of the main cooling circuit, by passage of the fluid from the pre-cooling circuit into the main cooling circuit. A heat shield cooling circuit for cooling a heat shield cools the second fluid refrigerating means of the pre-cooling circuit.

1. Field of The Invention
This invention relates to a vacuum vessel having a member cooled to a low temperature in use, for example, to the temperature of liquid helium, and means for cooling the cooled member. More particularly, but not exclusively, the present invention relates to a cryopump for condensing and adsorbing gas molecules on a cryopanel surface cooled to an ultra-low temperature, such as is used in a nuclear fusion reactor, etc.
2. Description of The Prior Art
The article "Cryopumps and cryogenic systems of prototype injector unit for JT-60", by T. Shibata et al., 9th International Cryogenic Engineering Conference, May 1982, describes a large scale cryogenic apparatus. A cryopump unit is used in each of a plurality of neutron beam injection devices disposed around a nuclear fusion apparatus. Each cryopump unit is cooled by liquid helium and liquid nitrogen. The cryopanel of each cryopump which is used for condensing and thus adsorbing gas molecules and exhausting them at a high speed is cooled to about 3.7K by liquid helium. A heat shield plate cooled to a low temperature of about 80K by liquid nitrogen is disposed around the cryopanel of each cryopump unit to avoid the cryopanel being directly heated by radiant heat from normal and high temperature portions outside the pump.
In known arrangements, the liquid helium that cools the cryopanel of each cryopump unit is produced collectively by a common large-sized liquid helium liquefaction refrigerator and is transferred to each cryopump unit through a heat insulated piping. Low temperature helium gas evaporating inside the cryopanel is recovered by the same large-scale liquid helium liquefaction refrigerator through another heat insulated piping. Liquid nitrogen, too, is produced collectively by a common large-sized liquid nitrogen liquefaction machine or is transferred from the same liquid nitrogen storage tank to each cryopump unit through a heat insulated piping, and the low temperature nitrogen gas evaporating inside the heat shield plate is emitted to the atmosphere.
In this known, large-sized cryopump, liquid helium is transferred from the large-scale liquid helium liquefaction refrigerator to each cryopump unit through a long heat insulated piping, and a large quantity of liquid helium evaporates inside the piping. This evaporated low temperature helium gas cannot be utilized for cooling the cryopanel, and moreover, increases the fluidization pressure loss inside the piping. Therefore, the pipe diameter of the heat insulating piping must be increased.
Heat entering the insulated piping is generally about 1 W/m, and when the length of the heat insulated piping reaches 200 m, liquid helium corresponding to heat of 200 W evaporates. Heat entering the helium at the cryopump is generally from several to some dozens of watts, so that most of the liquid helium is consumed merely for cooling the heat insulated piping.
The known large-sized cryopump thus needs a large quantity of liquid helium for cooling the heat insulated piping. For this reason, a large-sized liquid helium liquefaction apparatus having a large power consumption has been required.
If gas leaks into the vacuum region of the vacuum insulated piping, the heat insulating effect is largely destroyed and a large quantity of liquid helium inside the piping evaporates, so that the heat transfer function stops, cooling the piping from ambient temperature cannot be achieved, and the function of the cryopump often stops.
Japanese Utility Model publication no. JP-U-62-167875 discloses cryopanels cooled by a helium circuit including a liquefying refrigerator and a liquid helium tank. A heat shield or baffle of louvers protects a cryopanel from ambient temperature parts.
The prior art technique described above cools a group of cryopumps with liquid helium produced by a concentrated type large-sized liquid helium liquefaction machine and transferred through heat insulated pipings disposed in the ambient atmospheric space. It therefore involves the following problems:
(1) high electric power is necessary for cooling the cryopanels, PA0 (2) an expensive large-sized liquid helium liquefaction apparatus is necessary, PA0 (3) long heat insulated piping having large diameters are necessary, PA0 (4) since the long piping must be first cooled, a long time (several days) is necessary for cooling the cryopanel, PA0 (5) heating the cryopanel needs a long time (several days), likewise. PA0 (6) the reliability of the cooling system is low.


A composite floor pad assembly includes a pair of interchangeable and reversible floor polishing pads having identical external diameters and central openings therethrough of an identical diameter. An intermediate connecting member having a plurality of hook-like members projecting from opposite surfaces thereof and provided with a central opening is detachably connected to opposing surfaces of the two floor polishing pads. A truncated, conical mandrel is also provided over which the pads and connecting member may be placed to facilitate alignment of the pads. The mandrel may be provided with an attachment member for detachably connecting the mandrel to an upper surface of a floor polishing machine.

The present invention is directed to a floor polishing pad assembly, and more specifically to a floor polishing pad for use with a floor polishing machine wherein the pad is comprised of two 5/8" thick floor polishing pads joined by a double-sided circular VELCRO disk therebetween.
Conventional floor polishing machines use a floor polishing pad which is comprised of a single 1" thick pad. The fibers of the pad do not wear down appreciably and the 1" thickness is primarily for providing cushioning so that the pad will get down into uneven ripples and dips in all floors. Although the pad can be reversed to utilize the fibers on the opposite surface, the fibers in the center of the thick pad are never used for polishing purposes but only to achieve the desired cushioning effect.


A borehole data transmission apparatus whereby a centrifugal pump impeller(s) is used to provide a turbine stage having substantial pressure characteristics in response to changing rotational speed of a shaft for the pressure pulsing of data from the borehole through the drilling mud to the surface of the earth.

The present invention relates to a borehole data transmission apparatus and more particularly to a borehole data transmission apparatus utilizing a centrifugal pump impeller to provide a turbine stage having substantial pressure response characteristics for the pressure pulsing of data from the borehole through the drilling mud to the surface of the earth.
It is well known to transmit measurement data from a measuring instrument at the downhole end of a drill string within a borehole by generating pressure variations within the mud flow passing along the drill string and to retrieve the transmitted data by sensing such pressure variations at the surface. Typically such data includes weight on the bit, RPM, natural gamma, formation resistivity, bottom hole temperature, bottom hole pressure, and virtually any information related to detectable conditions. Such information is usually transmitted from the bottom of the borehole to the surface as a series of hydraulic pulses produced in, and transmitted through, the drilling fluid. The information, in the form of pulses, may be transmitted to the surface without disturbing the normal drilling operations or ceasing the flow of drilling fluid. At the surface, the pressure pulses are detected, usually converted to electrical signals, and processed to provide the sought for information in a useable format.
It is common to create pressure pulses in drilling fluid by periodically interrupting the normal flow of the fluid through the drill string, or diverting a portion of the flow into the annulus of the drill string, to form a series of pulses in the drilling fluid which is normally pressurized and which normally flows down through the drill string and back up the annulus around the outer surface of the drill string.
Thus, for example, a variety of systems have been used to form the pressure pulses and to effect transmission to the surface. In most instances, the pulsing system involves some form of valve so positioned that the entire fluid flow through the drill string also flows through the valve. The recognized difficulty with this arrangement is that the drilling fluid, due to its composition, the rate of flow and volume thereof, tends to be quite abrasive. As a result of the abrasive conditions of the drilling fluid and the fact that the transmission of data may involve a significant number of pulses, the life of the valves is somewhat limited.
A number of U.S. Patents show the use of rotary "turbine-like" valves which include a rotor and a stator. Both the rotor and stator have slots which can be aligned to open the valve and let drilling fluid pass through or misaligned to close the valve and provide a strong resistance to the passing of the drilling fluid. U.S. Pat, No. 4,956,823 of Russell shows a signal transmitter comprising main and secondary impellers angularly displaceable relative to one another in response to a change in load of a generator so as to vary the flow passage area and therefore the pressure drop across the rotating impeller assembly. U.S. Pat. No. 3,705,603 of Hawk refers to "a motor actuated rotary valve" which turns between an open position and a closed position in a rotary fashion. Turbines are also used for generating the electrical power needed to operate the logging-while-drilling apparatus. This is shown in the patents referenced, but is also used with non-rotary valves to create the pres-sure pulses as shown in U.S. Pat. No. 3,737,843 of Le Peuvedic et al. Numerous other patents show the use of turbines for generating power in a downhole logging-while-drilling apparatus and also show the use of rotary turbine-like valves which operated in an open and shut mode for generating the pressure pulses. Those systems shown in the patents referenced which use rotary valves for periodically interrupting a drilling fluid in order to generate pulses are motor actuated with the electrical power generated by a separate turbine motor.
The Applicant of the present invention is also the inventor of a logging-while-drilling tool shown in U.S. Pat. No. 4,734,892 which includes a variable rotation device in the form of a turbine rotor(s) of an axial turbine stage(s) with a changing pressure drop across the stage depending on the rotor rotational speed (RPM). The variability of the turbine rotor RPM is caused by changing of torsional loading torque on the rotor shaft. Such variable rotation of the turbine rotor generates the variable pressure drop across the turbine stage(s) to form the pressure wave signal in the drilling fluid.
The degree of torsional loading required on the rotor shaft in order to generate the pressure wave signal, is a function of the pressure response characteristics of the rotational device. Rotational devices are known which have different pressure response characteristics with respect to rotor rotational speed. A rotational device without significant pressure response characteristic will require significant torsional torque to generate the variable pressure drop across the turbine stage(s) thereby resulting in reducing the useful life of the device due to the friction and stress in the rotor shaft. Alternatively, multiple rotational elements could be configured to provide multiple turbine stages, the cumulative effect thereby creating pressure response characteristics across the several turbine stages. However, the downhole data transmission devices having multiple turbine stages must be of a relatively large axial size in order to generate the required significant pressure response across the several turbine stages for the data transmission.
It is an object of this invention to provide a simple, inexpensive, and compact borehole data transmission device having substantial pressure response characteristics for borehole pulse data transmission.
It is another object of the present invention to provide a borehole data transmission device having substantial pressure response characteristics across the turbine stage(s) thereby minimizing the number of turbine stage(s) required, resulting in a compact data transmission device.
Additional objects, advantages and novel features of the invention will become apparent to those skilled in the art upon examination of the following and by practice of the invention.


Crosslinked compounds of hyaluronic acid and the derivatives thereof, prepared by the technique of precipitation induced by supercritical antisolvent (SAS), can be used to advantage for the preparation of biomaterials for use in the field of medicine and surgery and in tissue engineering for medical and surgical purposes.

The present invention describes a process for the preparation of autocrosslinked compounds of hyaluronic acid and the derivatives thereof by the technique of precipitation induced by supercritical antisolvent (SAS).
These crosslinked compounds of hyaluronic acid and the derivatives thereof can be used to advantage for the preparation of biomaterials for use in the field of medicine and surgery and in tissue engineering for medical and surgical purposes.
Hyaluronic acid is a heteropolysaccharide composed of alternating residues of D-glucuronic acid and N-acetyl-D-glycosamine. It is a straight-chained polymer with a molecular weight that varies between 50,000 and 13,000,000 Da according to, the source from which it is obtained and the methods of preparation and determination used. It is naturally present in the pericellular gels, in the fundamental substance of connective tissue and in vertebrate organisms, of which it is one of the chief components, in the synovial fluid of joints, in the vitreous humor, in the human umbilical cord tissues and in rooster combs.
Hyaluronic acid plays a vital role in many biological processes such as tissue hydration, proteoglycan organisation, cell differentiation, proliferation and angiogenesis (J. Aigner et al., L. Biomed. Mater. Res. 1998, 42, 172-181).
It is known that hyaluronic acid fractions can be used to facilitate tissue repair, as substitutes for the intraocular fluid, or they can be administered by the intra-articular route to treat joint pathologies, as described in European Patents Nos. 0138572 and 0535200.
Hyaluronic acid plays a fundamental role in the tissue repair process, especially in the early stages of granulation, stabilising the coagulation matrix and controlling its degradation, favouring the recruitment of inflammatory cells such as polymorphonucleate leukocytes and monocytes, of mesenchymal cells such as fibroblasts and endothelial cells and, lastly, orientating the successful migration of epithelial cells.
It is known that the application of hyaluronic acid solutions is able to accelerate healing in patients suffering from sores, wounds and burns. The role of hyaluronic acid in the various stages of the tissue repair process has been described by the construction of a theoretical model by Weigel, P. H. et al.: xe2x80x9cA model for the role of hyaluronic acid and fibrin in the early events during the inflammatory response and wound healingxe2x80x9d, J. Theor: Biol:, 119, 219, 1986.
The use of low-molecular-weight hyaluronic acid fractions for the preparation of pharmaceutical compositions with bone-inducing properties (U.S. Pat. No. 5,646,129) is also known.
Hyaluronic acid derivatives maintain all the properties of the above glycosaminoglycan, with the advantage that they can be processed in various forms and that their solubility and degradation times can be varied according to the percentage of their derivation (EP 0216453 B1).
Moreover, also known are the total or partial esters of hyaluronic acid and the autocrosslinked derivatives of hyaluronic acid, their use in the pharmaceutical and cosmetic fields and in that of biodegradable materials (U.S. Pat. Nos 4,851,521; 4,965,353; 5,676,964).
The process known to date for the preparation of autocrosslinked derivatives of hyaluronic acid has the disadvantage that it is difficult to achieve homogeneous autocrosslinking throughout the mass of the product. Indeed, said process consists in preparing a solution of hyaluronic acid salt with tetrabutylammonium (HA-TBA) in an organic solvent such as N-methyl-pyrrolidone (NMP), dimethylsulfoxide (DMSO) or dimethylformamide (DMF) at a temperature of below 0xc2x0 C., agitating constantly while a solution of 2-chloro-1-methyl-pyridinium iodide (CMPJ) is added to whichever solvent or organic solvent is being used, the quantity of crosslinking agent being 25% that of the polymer mass. As soon as contact is made, the CMPJ produces crosslinking in the HA-TBA and, as its viscosity increases the solid becomes segregated before the crosslinking agent is homogeneously distributed. It therefore tends to settle preferentially on the solid and is no longer able to penetrate into the solution, leading to uneven crosslinking.
The ability of antisolvent fluids such as carbon dioxide (CO2) to solubilise in organic solvents under increased pressure has been exploited, in the present invention, to try to control the crosslinking reaction which is characterised by very rapid kinetics, especially in the early stage of mixing the reagents.
Rendering liquids far less viscous by swelling them makes it possible to achieve a mixture more rapidly and more efficiently than by the traditional process.
By compressing the antisolvent fluid it is possible to work in a swollen, and therefore dispersed environment and to control the crosslinking reaction once it has begun, slowing it down.
Addition of the crosslinking agent to the swollen mass is very rapid because of a specially designed injection system. Because of the swelling caused by the compressed antisolvent, the agitation of the mass and the fast injection of the crosslinking agent, it is possible to control the rate of crosslinking at the onset at temperatures of between 0 and 20xc2x0 C., preferably 10xc2x0 C.
At this temperature, the viscosity of the medium is such as will allow good homogenisation of the mass, unlike in the case of the conventional process that has to be conducted at temperatures of around xe2x88x9220xc2x0 C.
It is essential to work below precipitation pressure so that the separation of the polymer from the liquid phase occurs through the effect of the crosslinking and is not induced by precipitation due to the antisolvent effect; in the latter case, the crosslinking agent is only able to trigger the reaction superficially because it is unable to penetrate within the precipitate.
The present invention describes a process for the preparation of autocrosslinked compounds of hyaluronic acid and the derivatives thereof by means of precipitation using the supercritical antisolvent (SAS) technique.
These crosslinked compounds of hyaluronic acid and the derivatives thereof can be used to advantage for the preparation of biomaterials for use in the medical and surgical fields and in tissue engineering in the medical-surgical field.
The equipment used the technique is illustrated in FIG. 1, wherein P=precipitator; PI=CO2 pump; P2=pump for the crosslinking agent; VM1, VM2=millimetric valves for flow adjustment; VNR=cut-off valve; V1=on-off valve; VT1, VT2=three-way valves; A=sampling loop; PE=post-expansion vessel; R=rotameter.
The process according to the present invention involves the following steps:
a) preparing solutions of quaternary ammonium salt of hyaluronic acid or the derivatives thereof and the crosslinking agent;
b) loading the solutions of quaternary ammonium salt and crosslinking agent into the precipitator and into the container respectively, the latter being fitted with a pump to suck up the liquid;
c) adjusting the rotation speed to within a range of 200-1000 rpm, preferably between 250 and 450 rpm;
d) adjusting the temperature to within a range of xe2x88x9220xc2x0 C. to 20xc2x0 C., preferably between 0 and 10xc2x0 C.;
e) adjusting the pressure of the fluid to below that of precipitation of the quaternary ammonium salt of hyaluronic acid or the derivatives thereof, which depends upon the solvent and the temperature;
f) injecting the solution of crosslinking agent into the precipitator at a greater pressure than that present in the precipitator in order to disperse all the crosslinking agent homogeneously in the starting polymer solution;
g) optionally, injecting a buffer solution into the precipitator;
h) increasing the temperature to+ between 20 and 50xc2x0 C., preferably between 15 and 40xc2x0 C.;
i) leaving it to react for between two and twelve hours, preferably six hours;
j) washing the product with a flow of antisolvent at a pressure of between 60 and 150 bar, preferably between 80 and 100 bar;
k) depressurising and harvesting the product.
The following hyaluronic acid derivatives are to be preferred:
partial esters of hyaluronic acid wherein part of the carboxy functions are esterified with alcohols of the aliphatic, aromatic, arylaliphatic, cycloaliphatic, heterocyclic series (EP 0216453 B1);
partial esters of hyaluronic acid wherein part of the carboxy functions are esterified with an arylaliphatic alcohol and the second part with long-chain, straight aliphatic alcohols with between 10 and 22 carbon atoms (WO 98/08876)
the partially O-sulfated (WO 95/25751) and/or N-sulfated derivatives (WO 98/45335);
the amide derivatives of hyaluronic acid.
The preferred quaternary ammonium salts are tetrabutylammonium salts. The crosslinking agents are, for example, 2-chloro-1-methyl-pyridinium iodide, 2-chloro-pyridine, 2-chloro-1-isopropyl-pyridinium iodide, 1-fluoro-2,4-dinitrobenzene.
The solutions are prepared in organic solvents such as N-methyl-pyrrolidone (NMP), dimethylsulfoxide (DMSO), dimethylformamide.

Process for the preparation of autocrosslinked compounds of hyaluronic acid and the derivatives thereof by the supercritical antisolvent technique


A display device for providing a virtual reality service is provided. The display device includes: a display configured to display a stereoscopic image; a user interface configured to receive a user command for enlarging or shrinking the stereoscopic image; and a processor configured to adjust a three-dimensional effect for the stereoscopic image to correspond to the user command when the user command is input, and control the display to display an enlarged image or a shrunk image in which the three-dimensional effect is adjusted.

Recently, in accordance with the development of electronic technology, users could receive three-dimensional (3D) images through head mounted displays (HMDs).
In this case, the user could receive a 3D image for a direction that he/she views depending on movement of his/her head to feel a more realistic 3D image unlike an existing monitor or television (TV).
However, in the case of enlarging or shrinking the 3D image, a disparity between a left-eye image and a right-eye image is excessively increased, such that a cross talk phenomenon occurs, or a disparity between a left-eye image and a right-eye image is decreased, such that an unnatural image is provided to the user.

Display device and control method therefor


A housing for developing latent fingerprints is formed by positioning a thermally stable porous support material in a hollow tubular member and impregnating the support material with a liquid cyanoacrylate which is allowed to cure. The housing can be placed on an end of a portable heating device having sufficient heat to vaporize the cyanoacrylate and project the vapors against an object to be tested for latent fingerprints.

It is long known that cyanoacrylate, in vapor form, adheres to fingerprints. Once the vapor cures, the cyanoacrylate forms a white polymer substance that reveals to the fingerprint. This technique is known as developing a latent fingerprint. Although his process produces good results, the present technology for developing latent prints involves a time consuming process that must be performed in closed quarters. Current technology uses sheet packets of thick liquid cyanoacrylate. The cyanoacrylate is spread on sheets of material and then sealed. To use, the packet is opened by pulling the two sheets apart which then exposes the cyanoacrylate to the air. Typically, these sheets are placed in a closed vessel such as a large aquarium with the object to be examined. The cyanoacrylate vapors can then adhere to the object, developing any prints that might be on the object. This process can take up to six hours. One system calls for placing several packets throughout a room and then sealing the room for up to 24 hours to develop any prints that may be inside.
Examples of patents that use this technique can be found in U.S. Pat. Nos. 4,550,041; 4,729,229; 4,260,645, and 4,613,515. As noted above, these devices and methods all suffer from the same drawbacks: they are slow, taking up to several hours to complete the process, and must be used in a closed container.
It is also known that heat accelerates the vaporization of the cyanoacrylate. U.S. Pat. No. 4,719,119 discusses the drawbacks of using heat as it was taught in 1983. Essentially, the heat process uses a laboratory "hot plate" to warm the cyanoacrylate. In use, the opened pouch is placed on the hot plate within a closed container. As the heat is applied, vaporization accelerates. Notwithstanding the safety problems associated with this technique, it still requires that the test be conducted within a closed container such as an aquarium.

Apparatus for cyanoacrylate fingerprint developing and method of use therefore


A method for preventing a relay attack of a smart key system for a vehicle according to the present invention accurately calculates a current spaced distance between an SMK unit and a fob key by using an RSSI included in a response signal and a current voltage level in a process of decoding the response signal when the fob key carried by a user receives a signal applied from the SMK unit installed in a vehicle and then transmits the response signal having at least two kinds of information to the SMK unit, and detects a challenge signal applied from the SMK unit installed in the vehicle and a noise signal included in the response signal, thereby enabling an operation of the vehicle only in a state where the carrier of the fob key secures a predetermined visual distance from the vehicle, and more definitely preventing a third party from breaking into the vehicle through RF bi-directional authentication.

In general, a smart key system for a vehicle refers to a system for preventing a vehicle from being robbed by allowing various functional operation units of a vehicle body to be operated only when a driver (or a user) carries a fob key and a smart key unit (hereinafter, referred to as an SMK unit) authorizes that the driver (or the user) is an authorized user by decoding an encoding code applied from the fob key.
That is, when the user approaches the vehicle within a predetermined distance while carrying the fob key, the SMK unit wakes up the fob key, performs a procedure of authorizing an ID of the authorized user by mutually communicating encoding data of a transponder embedded in the fob key, and then switches operations of various functional operation units, such as starting an engine of the vehicle, opening/closing a trunk door, and opening/closing of a side door, to be operable when it is determined that the user is the authorized user.
However, when the side door is opened, a signal transfer system may be divided into two situations as described below. That is, the first case is a case where the SMK unit authorizes the authorized user ID, and then the user presses a switch related to an operation of the side door among the operation switches of the various functional operation units provided in the fob key and transmits a predetermined signal to the SMK unit, and the second case is a case where the SMK unit authorizes the authorized user ID, and then the user actively pulls a knob of the side door and transmits a triggering signal generated from the knob of the side door to the SMK unit.
In the meantime, the authorized user ID authorizing process performed between the SMK unit and the fob key in the smart key system in the related art will be briefly described below.
First, when the fob key approaches the vehicle within a predetermined distance or directly pulls the knob of the side door, a challenge signal is generated, and the generated challenge signal is modulated and demodulated by the SMK unit and is received by an LF receiver of the fob key.
When the fob key receives the challenge signal, a response signal including an encoding code is transmitted by using an RF transmitter of the fob key, the RF receiver of the SMK unit receives the response signal and determines whether the response signal is matched with a predetermined encoding code, and then enables the functional operation unit to be operated based on the fob key carried by the authorized user only when the response signal is matched with the predetermined encoding code.
However, even in a case where the user actually carrying the fob key goes beyond a predetermined distance (for example, a maximum visual distance, at which the driver views the vehicle) from the vehicle, the smart key system in the related art maintains a state in which a third party is capable of operating the various functional operation units when a normal challenge signal is transmitted to the fob key from the vehicle (which is referred to as a "relay attack"), so that there is a problem in that the vehicle or equipment stored in the vehicle may be robbed.
Particularly, in theory, when the fob key carried by the authorized user goes beyond a predetermined distance (a challenge signal reaching distance) from the vehicle, the fob key cannot receive the challenge signal, the aforementioned response signal including the encoding code itself is not transmitted, so that there may be no problem, but when a plurality of repeaters (a repeater 1 and a repeater 2) having an unlawful intention is provided between the vehicle and the fob key of the authorized user, there still occurs a problem in that a third party may break into the vehicle.

Method for preventing relay attack on vehicle smart key system


A method, apparatus, and storage medium for temporal indexing of at least two audio, video, and data (AVD) streams, each AVD stream comprising a plurality of AVD stream chunks. A stream information data stream (SIDS) having a plurality of SIDS chunks is stored, each SIDS chunk corresponding to a corresponding AVD stream chunk for each of the at least two AVD streams. A temporal index stream (TIS) having a plurality of TIS chunks is also stored, each TIS chunk corresponding to a corresponding SIDS chunk. Each TIS chunk comprises a time stamp for indicating the current time and an offset for locating the corresponding SIDS chunk. Each SIDS chunk comprises an SIDS chunk entry for each of the at least two AVD streams that is currently active, each SIDS chunk entry comprising an offset for locating the corresponding AVD stream chunk of each active AVD stream of the at least two AVD streams.

1. Field of the Invention
The present invention relates to data processing systems, and, in particular, to apparatuses and method for providing for temporal indexing for synchronized storing and retrieval of multiple audio, video, and data streams.
2. Description of the Related Art
In computer systems, there is a need for storage and retrieval of various types of data streams. These data streams can be audio data streams, video data streams, or other types of (non-video, non-audio) data streams. There is often a need to store (and retrieve) multiple streams of such data, and to maintain the temporal synchronization of such data so that, upon retrieval or playback, streams that occurred simultaneously maintain the correct time synchronization. Audio, video, and data streams sometimes referred to collectively herein as "A/V/D streams," and storage and retrieval of A/V/D streams is (also referred to as record and playback, or write and read, of such data. In computer systems such as data conferencing (or "teleconferencing") systems, a plurality of users are provided with the ability to have an electronic on-line meeting even if the users are not physically in the same room or building. Using application programs for this purpose, modem communication systems have enabled the ability to have a "meeting" wherein all users participate in the meeting through their individual computer systems and share data, graphics, text, and other types of information. Users may communicate with one another, sharing data in the form of graphical images, text, or other "annotations" and other information represented on the computer system display. This is analogous to a meeting where participants in a face-to-face meeting may display information to one another on a whiteboard and other participants may add annotations, delete, or otherwise modify the board. In some usages, video data may also be shared among a plurality of connected users during such teleconferences, or video conferences. For such an electronic conferencing system, it is desirable for individual users to be able to selectively record (and play back) any or all of the individual A/V/D streams that constitute the data conference.
Some current methods, such as those using the Microsoft.RTM. audio-video interleave ("AVI") file standard, allow the recording and indexing of A/V/D streams. Current techniques utilizing such interleave formats, however, do not provide an efficient means of locating (seeking) given time-points within the A/V/D recording, especially when the various streams are not all simultaneously recorded (e.g., some streams are paused and resumed while others are still continuously recorded). Further, once a particular location in the file has been seeked which corresponds to a particular time-point, such current methods do not provide a means for selectively reading one or more of the streams while maintaining synchronization between those streams. Thus, prior art indexing and synchronization methods suffer from several disadvantages. There is, therefore, a need for methods and apparatuses that provide for temporal indexing for synchronized storing and retrieval of multiple audio, video, and data streams.
There is also a need to be able to retrieve and playback certain defined events that occur during a data conference. Current methods, such as those utilizing the AVI file format standard, do not provide a means for tagging an event within a given A/V/D recording which may be randomly accessed for playback. There is, therefore, a need for methods and apparatuses that provide for event tagging for synchronized storing and retrieval of multiple A/V/D streams.
Additionally, various A/V/D streams may be paused and resumed independently of one another during a data conference. There is, therefore, a need for methods and apparatuses for creation and management of multiple discontinuous segments of different types of data (i.e. A/V/D) streams in a single file.

Apparatus and method for temporal indexing of multiple audio, video and data streams


It has been discovered that the incorporation of fluorinated gases, especially a perfluorocarbon such as octafluoropropane, into synthetic polymeric microparticles, significantly enhances echogenicity as compared with microparticles having air incorporated therein. The microencapsulated perfluorocarbon is manufactured with a diameter suitable for the targeted tissue to be imaged, for example, for intravenous or oral administration. In one embodiment, bioadhesive microparticles are formed for enhanced imaging of mucosal surfaces.

The present invention is generally in the area of diagnostic imaging agents, and is particularly directed to microencapsulated ultrasound imaging contrast agents.
When using ultrasound to obtain an image of the internal organs and structures of a human or animal, ultrasound waves, waves of sound energy at a frequency above that discernable by the human ear, are reflected as they pass through the body. Different types of body tissue reflect the ultrasound waves differently and the reflections that are produced by the ultrasound waves reflecting off different internal structures are detected and converted electronically into a visual display.
For some medical conditions, obtaining a useful image of the organ or structure of interest is especially difficult because the details of the structure are not adequately discernible from the surrounding tissue in an ultrasound image produced by the reflection of ultrasound waves absent a contrast-enhancing agent. Detection and observation of certain physiological and pathological conditions may be substantially improved by enhancing the contrast in an ultrasound image by infusing an agent into an organ or other structure or interest. In other cases, detection of the movement of the contrast-enhancing agent itself is particularly important. For example, a distinct blood flow pattern that is known to result from particular cardiovascular abnormalities may only be discernible by infusing a contrasting agent into the bloodstream and observing the dynamics of the blood flow.
Materials that are useful as ultrasound contrast agents operate by having an effect on ultrasound waves as they pass through the body and are reflected to create the image from which a medical diagnosis is made. Different types of substances affect ultrasound waves in different ways and to varying degrees. Moreover, certain of the effects caused by contrast-enhancing agents are more readily measured and observed than others. In selecting an ideal composition for a contrast-enhancing agent, one would prefer the substance that has the most dramatic effect on the ultrasound wave as it passed through the body. Also, the effect on the ultrasound wave should be easily measured. There are three main contrast-enhancing effects which can be seen in an ultrasound image: backscatter, beam attenuation, and speed of sound differential.
BACKSCATTER
When an ultrasound wave that is passing through the body encounters a structure, such as an organ or other body tissue, the structure reflects a portion of the ultrasound wave. Different structures within the body reflect ultrasound energy in different ways and in varying strengths. This reflected energy is detected and used to generate an image of the structures through which the ultrasound wave has passed. The term "backscatter" refers to the phenomena in which ultrasound energy is scattered back towards the source by a substance with certain physical properties.
It has long been recognized that the contrast observed in an ultrasound image may be enhanced by the presence of substances known to cause a large amount of backscatter. When such a substance is administered to a distinct part of the body, the contrast between the ultrasound image of this part of the body and the surrounding tissues not containing the substance is enhanced. It is well understood that, due to their physical properties, different substances cause backscatter in varying degrees. Accordingly, the search for contrast-enhancing agents has focused on substances that are stable and non-toxic and that exhibit the maximum amount of backscatter.
The capability of a substance to cause backscatter of ultrasound energy depends on characteristics of the substance such as its ability to be compressed. When examining different substances, it is useful to compare one particular measure of the ability of a substance to cause backscatter known as the "scattering cross-section." The scattering cross-section of a particular substance is proportional to the radius of the scatterer, and also depends on the wavelength of the ultrasound energy and on other physical properties of the substance, J. Ophir and K. J. Parker, Contrast Agents in Diagnostic Ultrasound, Ultrasound in Medicine & Biology, vol. IS, n. 4, p. 319, 323 (1989).
In evaluating the utility of different substances as image contrasting agents, one can calculate which agents should have the higher scattering cross-section and, accordingly, which agents should provide the greatest contrast in an ultrasound image. It can be assumed that the compressibility of a solid particle is much less than that of the surrounding medium and that the density of the particle is much greater. Using this assumption, the scattering cross section of a solid particle contrast-enhancing agent has been estimated as 1.75. Ophir and Parker, supra, at 325. For a pure liquid scatterer, the adiabatic compressibility and density of the scatterer and the surrounding medium are likely to be approximately equal, which would yield the result that liquids would have a scattering cross-section of zero. However, liquids may exhibit some backscatter if large volumes of a liquid agent are present. For example, if a liquid agent passes from a very small vessel to a very large one such that the liquid occupies substantially all of the vessel, the liquid may exhibit measurable backscatter. Nevertheless, it is appreciated by those skilled in the art that pure liquids are relatively inefficient scatterers compared to free gas microbubbles.
BEAM ATTENUATION
Another effect which can be observed from the presence of certain solid contrast-enhancing agents, is the attenuation of the ultrasound wave. Image contrast has been observed in conventional imaging due to localized attenuation differences between certain tissue types. K. J. Parker and R. C. Wang, "Measurement of Ultrasonic Attenuation Within Regions selected from B-Scan Images," IEEE Trans. Biomed. Enar. BME 30(8), p. 431-37 (1983); K. J. Parker, R. C. Wang, and R. M. Lerner, "Attenuation of Ultrasound Magnitude and Frequency Dependence for Tissue Characterization," Radiology, 153(3), p. 785-88 (1984). It has been hypothesized that measurements of the attenuation of a region of tissue taken before and after infusion of an agent may yield an enhanced image. However, techniques based on attenuation contrast as a means to measure the contrast enhancement of a liquid agent are not well-developed and, even if fully developed, may suffer from limitations as to the internal organs or structures with which this technique can be used. For example, it is unlikely that a loss of attenuation due to liquid contrast agents could be observed in the image of the cardiovascular system because of the high volume of liquid contrast agent that would need to be present in a given vessel before a substantial difference in attenuation could be measured.
The absorption of energy by the particles occurs by a mechanism referred to as "relative motion." The change in attenuation caused by relative motion can be shown to increase linearly with particle concentration and as the square of the density difference between the particles and the surrounding medium. K. J. Parker, et al., "A Particulate Contrast Agent with Potential for Ultrasound Imaging of Liver," Ultrasound in Medicine & Biology, Vol. 13, No. 9, p. 555, 561 (1987). Therefore, where substantial accumulation of solid particles occurs, attenuation contrast may be a viable mechanism for observing image contrast enhancement although the effect is of much smaller magnitude than the backscatter phenomenon and would appear to be of little use in cardiovascular diagnoses.
SPEED OF SOUND DIFFERENTIAL
An additional technique to enhance contrast in an ultrasound image has been proposed based on the fact that the speed of sound varies depending on the media through which it travels. Therefore, if a large enough volume of an agent, through which the speed of sound is different than the surrounding tissue, can be infused into a target area, the difference in the speed of sound through the target area may be measurable.
In summary, diagnostic ultrasound is a powerful, non-invasive tool that can be used to obtain information on the internal organs of the body. The advent of grey scale imaging and color Doppler have greatly advanced the scope and resolution of the technique. Although techniques for carrying out diagnostic ultrasound have improved significantly, and for making and using contrast agents, there is still a need to enhance the resolution of the imaging for cardiac perfusion and cardiac chambers, solid organs, renal perfusion; solid organ per fusion; and Doppler signals of blood velocity and flow direction during real-time imaging.
A variety of natural and synthetic polymers have been used to encapsulate imaging contrast agents, such as air. Schneider et al., Invest. Radiol., Vol. 27, pp. 134-139 (1992) describes three micron, air-filled polymeric particles. These particles were reported to be stable in plasma and under applied pressure. However, at 2.5 MHz, their echogenicity was low. Another type of microbubble suspension has been obtained from sonicated albumin. Feinstein et al., J. Am. Coll. Cardiol., Vol. 11, pp. 59-65 (1988). Feinstein describes the preparation of microbubbles that are appropriately sized for transpulmonary passage with excellent stability in vitro. However, these microbubbles are short-lived in vivo, having a half life on the order of a few seconds (which is approximately equal to one circulation pass) because of their instability under pressure. Gottlieb, S. et al., J. Am. Soc. Echo., Vol. 3, pp. 328 (1990), Abstract; and Shapiro, J. R. et al., J. Am. Coll. Cardiol., Vol. 16, pp. 1603-1607 (1990). Gelatin-encapsulated air bubbles have been described by Carroll et al. (Carroll, B. A. et al., Invest. Radiol., Vol. 15, pp. 260-266 (1980), and Carroll, B. A. et al., Radiology, Vol. 143, pp. 747-750 (1982)), but due to their large sizes (12 and 80 .mu.m) they would not be likely to pass through pulmonary capillaries. Gelatin-encapsulated microbubbles have also been described in PCT/US80/00502 by Rasor Associates, Inc. These are formed by "coalescing" the gelatin.
Microbubbles stabilized by microcrystals of galactose (SHU 454 and SHU 508) have also been reported by Fritzch et al. Fritzsch, T. et al., Invest. Radiol. Vol. 23 (Suppl 1), pp. 302-305 (1988); and Fritzsch, T. et al., Invest. Radiol., Vol. 25 (Suppl 1), 160-161 (1990). The microbubbles last up to 15 minutes in vitro but less than 20 seconds in vivo. Rovai, D. et al., J. Am. Coll. Cardiol., Vol. 10, pp. 125-134 (1987); and Smith, M. et al., J. Am. Coll. Cardiol., Vol. 13, pp. 1622-1628 (1989).
European Patent Application No. 90901933.5 by Schering Aktiengesellschaft discloses the preparation and use of microencapsulated gas or volatile liquids for ultrasound imaging, where the microcapsules are formed of synthetic polymers or polysaccharides. European Patent Application No. 91810366.4 by Sintetica S. A. (0 458 745 A1) discloses air or gas microballoons bounded by an interfacially deposited polymer membrane that can be dispersed in an aqueous carrier for injection into a host animal or for oral, rectal, or urethral administration, for therapeutic or diagnostic purposes. WO 92/18164 by Delta Biotechnology Limited describes the preparation of microparticles by spray drying under very controlled conditions as to temperature, rate of spraying, particle size, and drying conditions, of an aqueous protein solution to form hollow spheres having gas entrapped therein, for use in imaging. WO 93/25242 describes the synthesis of microparticles for ultrasonic imaging consisting of a gas contained within a shell of polycyanoacrylate or polyester. WO 92/21382 discloses the fabrication of microparticle contrast agents which include a covalently bonded matrix containing a gas, wherein the matrix is a carbohydrate. U.S. Pat. Nos. 5,334,381, 5,123,414 and 5,352,435 to Unger describe liposomes for use as ultrasound contrast agents, which include gases, gas precusors, such as a pH activated or photo-activated gaseous precursor, as well as other liquid or solid contrast enhancing agents.
U.S. Pat. No. 5,393,524 to Quay discloses the use of agents, including fluorocarbons, for enhancing the contrast in an ultrasound image. The agents consist of extremely small bubbles, or microbubbles, of selected gases, which exhibit long life spans in solution and are small enough to traverse the lungs, enabling their use in ultrasound imaging of the cardiovascular system and other vital organs. WO95/23615 by Nycomed discloses microcapsules for imaging which are formed by coacervation of a solution, for example, a protein solution, containing a perfluorocarbon. PCT/US94/08416 by Massachusetts Institute of Technology discloses microparticles formed of polyethylene glycol-poly(lactide-co-glycolide) block polymers having imaging agents encapsulated therein, including gases such as air and perfluorocarbons. As described in WO94/16739 by Sonus Pharmaceuticals, Inc., while solids and liquids reflect sound to a similar degree, gases are known to be more efficient and are the preferred media for use as ultrasound contrast agents. In fact, as shown by example 12 of the Sonus PCT application, protein microcapsules were dismissed as raising safety concerns (as well as efficacy issues) when administered to mini-pigs, as compared to emulsions or colloidal suspensions.
In all of these cases it is desirable to enhance the echogenicity of the imaging agent, in conjunction with enhancing or maintaining the stability and ease of manufacturing of the imaging agent.
It is therefore an object of the present invention to provide microparticles made from synthetic polymers with significantly enhanced echogenicity.

Microencapsulated fluorinated gases for use as imaging agents


An automatic gain control system is disclosed which utilizes a voltage coolled vario-losser means to vary the AGC System output. The control voltage is derived from the lowest detected level from any of a plurality of narrow band pass filters, such as the monolithic crystal type now available, each of which has a different peak transmittance frequency which is close to but different from a frequency of interest.

This invention relates to spectrum analyzers such as are used in studying sea noise spectra, and more particularly to improvements in the AGC (automatic gain control) of sea noise spectrum analyzers, for example analyzers of the lofar (low frequency analyzer and recorder) type.
Signals received at underwater hydrophones generally include broadband noises due to wind and wave action, shipping flow noise, and seismic disturbances. Also present are discrete frequencies from marine propulsion machinery. A representative spectrum has a smooth background level with some peaks of discrete frequencies, the background level being substantially of the character of white noise.
When a spectrum analyzer output with widely varying spectral densities is presented on a limited dynamic display medium, an automatic gain control is needed. Traditionally, lofar analysis has been displayed on "Timefax" electrosensitive paper which has a very limited range of approximately 6 db.
Since a lofar spectrum may have a range of 40 db across the frequency band of interest, a stiff AGC is required to maintain the output within the 6 db range of the display medium. In a typical lofar spectrum analyzer with AGC, the AGC filter bandwidth is about 50 times the analyzing bandwidth, that is 10 Hz vs 0.2 Hz, and the AGC stiffness is about 1 db change of the output for a 15 db change of the input. Now, a strong signal within the AGC filter bandwidth causes a decrease in gain throughout the AGC filter bandwidth and hence a "whitening" of the recorded spectrum response on the electrosensitive paper about the strong signal to the width of the AGC filter. If weak signals are present at frequencies falling in the area of whitening, they will not be displayed. One prior art approach to overcoming the problem of whitening is found in U.S. Pat. No. 2,996,667 issued to R. R. Galbreath.
Recent improvements in filter techniques have made available narrow band pass filter devices such as monolithic crystal filters which are considerably more stable than filters obtainable before and which are more discriminating in their band pass characteristics.

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


A hydraulic door operator includes a reversible hydraulic pump driven by an electric motor and connected in a closed loop to a reversible hydraulic motor which operates the door. A bypass valve assembly is connected across the loop between the pump and hydraulic motor. The bypass valve assembly is operative when fluid is delivered by the pump to drive the motor in one direction so that a portion of the fluid flow is bypassed from reaching the motor. When the pump is operated to deliver fluid to drive the motor in the opposite direction, the bypass valve assembly is inoperative. When operative, the bypass assembly will cause the motor to be driven at a slower speed than it will be driven when the bypass valve assembly is inoperative.

This invention relates to industrial door operators, and particularly to a hydraulic control system for the door operator which provides different speeds in opening and closing the door.
Door operators are used to open and close doors that are mounted for swinging or sliding movement between open and closed positions, or for doors that are mounted to unroll and roll-up for closing and opening door openings. The industrial doors may be used for a variety of purposes such as closing the entry ways to cold storage environments. The industrial doors, especially those used for cold storage purposes, are usually either a single panel or a by-parting sliding panel which is moved by a mechanical drive system that includes a chain loop above the doors and a reversible motor for driving the chain.
Hydraulic systems for door operators have been proposed. Examples of hydraulic door operators are found in U.S. Pat. No. 4,296,570 issued Oct. 27, 1981 to George C. Balbach, et al. and assigned to the assignee of this invention. In such hydraulic systems, a reversible hydraulic pump, driven by an electric motor, is connected by a closed loop to a reversible hydraulic motor which in turn drives the mechanical drive for the door.
The speed of operation of the door is very important. When the doors are used in a cold storage environment, they must be kept open for the shortest possible duration consistent with safety. Typically, the door will be driven open at a very rapid speed and will be closed at a second slower speed to ensure pedestrian and vehicle clearance through the door opening before closing occurs. In hydraulic door operators, this two-speed operation (i.e. one speed for opening and a second slower speed for closing) has typically been accomplished by using a two-speed electric motor to drive the hydraulic pump. The pump is driven at one speed to power the motor to drive the door to an open position, and the pump is driven at a second slower speed to power the motor to drive the door to a closed position.
Another suggested way to achieve two-speed operation in a hydraulic door operator is to insert a restricted orifice in a connection between the pump and the motor so that when fluid flow is delivered by the pump to drive the motor in a direction to close the door, the fluid flow is forced through the restricted orifice and the flow is reduced, thereby driving the motor at a slower speed. The restricted orifice is not in the flow path of fluid delivered to the door in a direction to drive the motor to open the door. Since the amount of flow delivered to the motor is governed by the flow that can be generated through the restricted orifice, a single speed electric motor can be used to power the hydraulic pump and the pump can be driven at the same speed regardless of whether the pump is driving the motor to open or close the door.
The use of a two-speed electric motor has the disadvantage of cost in that such motors are significantly more costly than single speed motors. The use of a restricted orifice to restrict flow between the pump and the motor has the disadvantage that it generates considerable heat buildup due to the back pressure that the restricted orifice creates.