A conductive composition for a biological electrode is capable of reducing the impedance between the electrode and the skin. A conductive gel composition for a biological electrode which is capable of electrically and physically connecting a living body to an electrode element and is composed of at least the following components: (1) a radical-polymerizable unsaturated compound; (2) a moisturizer serving as a plasticizer and functioning to supplementing and promoting the physiological humidifying function of the horny layer; (3) a polymerization initiator; and (4) a crosslinking agent. This moisturizer serves also as a plasticizer and, furthermore, elevates the moisture content in the horny layer at the application of this composition. The above-mentioned composition may further contain a plasticizer selected from among polyhydric alcohols, amines and ethers.

This invention relates to a conductive composition to be located between the skin and an electrode element when a biological electrode is applied to the skin.
A biological electrode consists of an electrode element made of silver, silver/silver chloride, carbon and the like and a conductive composition connecting the electrode element to the skin and is applied to the surface of a living body in order to output some bioelectrical phenomena (e.g., electrocardiogram, electromyogram, etc.) or electrically stimulate the living body.
Normal human skin has an external layer called xe2x80x9chorny layerxe2x80x9d which protects the living body against the invasion of various foreign factors. When the skin is contacted with the dry atmosphere, the moisture is lost from the horny layer. Also, the moisture content in the horny layer is reduced as aging proceeds. In such cases, the electrical resistance of the horny layer is elevated. The surface of the skin is not smooth but uneven and has a complicated shape, for example, being curved.
When an electrode element is contacted directly with the skin surface containing less moisture in the horny layer, it is frequently observed that the contact of the electrode element to the skin is inhibited and thus the effective contact area is reduced. As a result, the contact resistance is elevated. In addition, the resistance of the horny layer per se has been elevated as described above. Thus the total electrical resistance is considerably elevated, which causes some troubles, for example, the bioelectrical signal thus output picks up noise, only an unstable record can be obtained, or no record can be obtained in some cases. When the surface of a living body is electrically stimulated via an electrode, the high resistance at the contact area brings about an increase in the current density and thus causes damages such as burn to the living body.
To solve these problems, conductive compositions in the form of liquid, jelly or gel are generally employed in biological electrodes so as to reduce the skin resistance between the living body and the electrode element. These conductive compositions contain a large amount of water and/or electrolytes such as NaCl or KCl which are externally absorbed by the skin horny layer to thereby reduce the skin resistance. Owing to the characteristics of the components, however, such a conductive composition per se has a low viscosity and a high flowability, which makes it difficult to stably sustain the conductive composition between the electrode element and the skin for a prolonged period of time. Thus the electrode element should be provided with a containment space or a holding means such as sponge for supporting the conductive composition. The electrode element should be further provided with an adhesive tape for fixing it on the skin surface. When an adhesive tape is used, however, repeated application and removal of the electrode element cause mechanical damage to the skin.
When an electrode element is applied to the skin surface for a long time via such a conductive composition in an ICU, Holter""s electrocardiography, etc., the conductive composition bears mechanical load due to body motion and external pressure. The conductive composition leaks from the electrode element to cause detachment of the electrode element or unstable contact of the electrode element with the skin, thus making it impossible to record the biological signals.
In addition, such a conductive composition is dried during application due to the evaporation of the moisture contained therein. Thus the skin resistance is elevated, thereby making the record of the biological signals unstable. Furthermore, the evaporation of the moisture contained in the conductive composition causes an increase in the chlorine ion concentration in the conductive composition, which induces skin irritation. After the removal of the electrode element, furthermore, such a conductive composition remains on the skin and causes rash.
There are electrode elements usable repeatedly and so-called disposable ones which are thrown away after being used once. In the former ones, a conductive composition is applied to the skin immediately before use. In the latter ones, on the other hand, a conductive composition has been preliminarily filled or incorporated into the electrode in many cases so that they can be easily applied. In the latter case, therefore, it is required to have a structure that the conductive composition is kept not dried until it is used and to store the conductive composition in an airtight package to thereby prevent it from drying during storage. Accordingly, an electrode element of the latter type should have a complicated structure as a whole with taking the use and storage thereof into consideration.
To solve the above-mentioned problems of the liquid conductive composition, there have been recently proposed solid gel conductive compositions which are not flowable but soft and sticky (cf. JP-B-62-44933, JP-B-63-43646, JP-B-63-59334 and JP-B-2-32892; the term xe2x80x9cJP-Bxe2x80x9d as used herein means an xe2x80x9cexamined published Japanese patent applicationxe2x80x9d). Since stickiness can be imparted to a solid gel conductive composition per se, it can be advantageously employed in a biological electrode without using any adhesive tape for fixation which is essentially required in electrodes with the conventional liquid conductive compositions.
However, the largest disadvantage of these solid gel conductive compositions resides in that they cannot sufficiently reduce the impedance between the electrode and the skin.
The solid gel conductive composition functions to reduce the impedance of the horny layer by allowing the horny layer to absorb the moisture and electrolytes such as KCl or NaCl contained in the conductive composition. In general, moisture contained in a solid gel includes free water which can freely move and bonding water which cannot freely move. The free water largely contributes to the reduction of the impedance of the horny layer. Thus a conductive composition with a larger content of free water can achieve the better effect. However an increase in the free water content might result in the oozing of water onto the solid gel surface or loss of the stickiness, thus damaging the functions characteristic to solid gels.
Conventional solid gels frequently contain polyhydric alcohols such as glycerol and propylene glycol as a plasticizer. Such a plasticizer is nonionic and does not participate in conductivity, which elevates the electrical resistance of the conductive composition per se containing the plasticizer.
To lower the electrical resistance, electrolytes such as KCl and NaCl are added to the conductive composition. It is furthermore required to add water thereto so as to facilitate the smooth migration of these electrolytes. When the moisture content is increased so as to facilitate the smooth migration of the electrolytes, however, the composition suffers from a decrease in the stickiness and thus becomes unusable, as described above. In addition, the percutaneous absorption of excessive moisture or electrolytes causes skin disorders such as rash. Namely, there is the upper limit of the moisture content and thus the impedance of the conductive composition against the skin cannot be sufficiently lowered by this method.
An object of the present invention is to provide a conductive composition for a biological electrode capable of elevating the moisture content in the horny layer and lowering the impedance between the electrode and the skin while causing little irritation without depending on any increase in the moisture content or the amount of electrolytes.
Thus, the present invention provides a conductive gel composition for a biological electrode which functions to electrically and physically connect a living body to an electrode element and comprises at least the following components: (1) a radical-polymerizable unsaturated compound; (2) a moisturizer serving as a plasticizer and having a function of supplementing and promoting the physiological humidifying function of the skin horny layer; (3) a polymerization initiator; and (4) a crosslinking agent.
The present invention also provides a conductive gel composition for a biological electrode comprises a plasticizer selected from the group consisting of polyhydric alcohols, amines and ethers, as well as the above-described components (1)-(4).

Conductive composition for biological electrode


We have discovered that coherent variation of at least two laser parameters can result in improved device performance, e.g., in pure amplitude or frequency modulation at frequencies substantially above 1 GHz, or in previously unattainable modulation frequencies. Among the relevant laser parameters are pumping rate, optical gain coefficient, photon lifetime, confinement factor, effective carrier temperature, output frequency and spontaneous emission factor. Exemplarily, the pumping rate and the optical gain are coherently varied such that the output radiation is free of chirp, or the output frequency and the effective carrier temperature are coherently varied such that the output radiation has constant amplitude.

Semiconductor lasers are well known. High-frequency modulation of the output radiation of semiconductor laser is an active area of optoelectronics. At present, amplitude modulation (AM) is the most widely used scheme. The conventional method of modulating the output amplitude of a semiconductor laser involves varying the laser pumping rate, by varying either electrical pump current or pump photon flux. This method is simple but is known to be limited to relatively low frequencies, typically .ltorsim.10 GHz. Furthermore, the modulation frequencies .gtorsim.1 GHz, the conventional modulation method is plagued by oscillations in the wavelength of the dominant mode of the output radiation. This phenomenon is generally referred to as "chirp". Both of the above referred to shortcomings of the conventional modulation method are due to an intrinsic resonance in the nonlinear laser system, the electron-photon resonance.
An alternative method for modulating the laser output is to directly control by external means the gain coefficient associated with the laser cavity. See, for instance, U.S. Pat. No. 5,023,878, which discloses a semiconductor laser which comprises, in addition to a "gain" section, a "loss" section that is optically coupled to the gain section but is electrically substantially isolated therefrom, such that the modal gain of the laser cavity can be changed through change of the electrical bias on the loss section.
Recently, a different and novel method of varying the gain coefficient associated with the active medium was disclosed. The method involves varying the effective carrier temperature T.sub.e in the laser active region. V. B. Gorfinkel et al., International Journal of Millimeter and Infrared Waves, Vol. 12, p. 649 (1991) disclose heating the electrons in the active region by driving an electric current through the active region, and V. B. Gorfinkel et al., Applied Physics Letters, Vol. 60, p. 3141 (1992) (incorporated hereby by reference ) disclose heating by inducing intersubband absorption in quantum wells in the active region. See also U.S. patent application Ser. No. 07/814,745, filed Dec. 24, 1992 for V. B. Gorfinkel et al. (also incorporated by reference), which inter alia discloses an optical modulator that utilizes carrier heating by means of intersubband absorption. High frequency modulation of T.sub.e by several tens of degrees has been demonstrated experimentally.
Although the method of varying T.sub.e in principle allows faster laser modulation than the conventional (pump current modulation) method, it neither eliminates the relaxation oscillations nor the frequency chirp.
Although at present most laser modulation is AM, there is a growing demand for frequency-modulated (FM) laser output. Coherent optical communication methods based on FM signals are advantageous because varying the optical frequency within the laser amplification bandwidth (approximately 10 nm) opens a larger number of communication channels that are available with AM methods. Existing FM techniques are typically based on the modulation of the optical cavity length of a single-mode laser and can be classified in two groups: those which use the electro-optic effect for the modulation and those that modulate the carrier concentration in specially designed cavity sections. In both schemes, it is the real part of the refractive index which is modulated by the external control means, leading to a variation of the optical path length.
The electro-optic effect typically is very fast. However, as usually implemented in the prior art, electro-optic FM is necessarily accompanied by oscillation in the carrier concentration in the laser, which limits the possible rate of modulation and typically results in output that exhibits amplitude as well as frequency modulation (AFM).
FM schemes that modulate the carrier concentration also exhibit drawbacks. If the carrier modulation occurs in a region of the laser wherein the semiconductor material has a larger bandgap than the material in the active region of the laser then the modulation speed typically is limited by a relatively slow (of order 1 ns) spontaneous recombination. If, on the other hand, the bandgap is the same in the two regions then the recombination can be faster, helped by the stimulated emission process, but the optical output of the laser typically will exhibit AFM.
To summarize, conventional methods of laser modulation, whether they are nominally AM or FM, at high modulation rates (above about 1 GHz) typically result in an unwelcome mixture of the amplitude and frequency modulation. Moreover, the most widely used conventional laser modulation methods, based on the modulation of laser pump rate, are limited to relatively low frequencies (.ltorsim.10 GHz).
It would be highly desirable to have available a method of modulating a semiconductor laser that can make possible higher modulation rates than are attainable with the conventional (pump current modulation) methods, and/or that makes possible substantially pure amplitude-modulated (AM) or pure frequency-modulated (FM) laser output at modulation frequencies higher than the currently attainable maximum frequency of about 1 GHz. This application discloses such a method, as well as apparatus for the practice of the method.
Higher modulation frequencies, and/or substantially pure AM or FM laser output modulation at rates in excess of the currently attainable maximum rate of about 1 GHz, would be of interest in many areas of technology, exemplarily in optical fiber communications and in optical data processing. We anticipate that the below disclosed method and apparatus can be advantageously used in these and other areas of technology.

Article that comprises a semiconductor laser, and method of operating the article


An LCD device is disclosed, having a polarizer of which a retardation value is variable on regions for compensation of gravity defect caused by an excess liquid crystal at room temperature, wherein the LCD device includes an LCD panel having a normal cell gap region and an abnormal cell gap region; and the polarizer having a compensated retardation value Δnd for the abnormal cell gap region.

1. Field of the Invention
The present invention relates to a liquid crystal display (LCD) device, and more particularly, to an LCD device including a polarizer of which a retardation value is variable on regions for compensation of gravity defect caused by an excess liquid crystal at room temperature.
2. Discussion of the Related Art
Demands for various display devices have increased with development of an information society. Accordingly, many efforts have been made to research and develop various flat display devices such as liquid crystal display (LCD), plasma display panel (PDP), electroluminescent display (ELD), and vacuum fluorescent display (VFD). Some species of flat display devices have already been applied to displays for various equipments.
Among the various flat display devices, liquid crystal display (LCD) devices have been most widely used due to their advantageous characteristics of a thin profile, light weight, and low power consumption, whereby the LCD devices provide a substitute for a Cathode Ray Tube (CRT). In addition to mobile type LCD devices such as a display for a notebook computer, LCD devices have been developed for computer monitors and televisions to receive and display broadcasting signals.
Despite various technical developments in the LCD technology having applications in different fields, research in enhancing the picture quality of the LCD device has been, in some respects, lacking as compared to other features and advantages of the LCD device. In order to use LCD devices in various environments as a general purpose display, the key to developing LCD devices depends on whether LCD devices can implement a high quality picture, such as high resolution and high luminance with a large-sized screen, while still maintaining lightness in weight, thin profile, and low power consumption.
Hereinafter, a related art LCD device and a problem of gravity defect therein will be described with reference to the accompanying drawings.
FIG. 1 is an exploded perspective view illustrating an LCD device according to the related art. As illustrated in FIG. 1, a related art LCD device includes first and second substrates 1 and 2 bonded to each other at a predetermined interval, and a liquid crystal layer 3 formed between the first and second substrates 1 and 2.
In more detail, the first substrate 1 includes a plurality of gate and data lines 4 and 5, a plurality of pixel electrodes 6, and a plurality of thin film transistors T. The plurality of gate lines 4 are formed on the first substrate 1 at fixed intervals, and the plurality of data lines 5 are formed in perpendicular to the plurality of gate lines 4 at fixed intervals. Then, the plurality of pixel electrodes 6, which are arranged in a matrix-type configuration, are respectively formed in pixel regions defined by the plurality of gate and data lines crossing each other. The plurality of thin film transistors T are switched according to signals of the gate lines for transmitting signals of the data lines to the respective pixel electrodes.
The second substrate 2 includes a black matrix layer 7 that excludes light from regions except the pixel regions P of the first substrate, R/G/B color filter layer 8 displaying various colors in correspondence with the pixel regions, and a common electrode 9 to obtain the picture image.
Then, the liquid crystal layer 3 is formed between the first and second substrates 1 and 2. The LCD device is driven according to an electric field generated between the pixel electrode 6 and the common electrode 9. Thus, it is possible to control the amount of light passing through the liquid crystal layer 3 according to the alignment of liquid crystal layer 3, thereby displaying the images.
This is referred to as a TN (Twisted Nematic) mode, which has the disadvantage of a narrow viewing angle. In order to overcome the disadvantage of the TN mode LCD device, an IPS (In-Plane Switching) mode LCD device has been developed and studied.
In case of the IPS mode LCD device, both pixel and common electrodes are formed at a predetermined interval in a pixel region of a first substrate, thereby generating an IPS mode electric field (transverse electric field). That is, a liquid crystal layer is driven with the transverse electric field.
In the meantime, a method for fabricating an LCD device is classified into a liquid crystal dropping method and a liquid crystal injection method according to a type of forming a liquid crystal layer between first and second substrates.
The liquid crystal injection method will be described in brief.
First, a container of receiving a liquid crystal material and an LCD panel are positioned inside a chamber. According as the chamber is maintained under a predetermined pressure, moisture and foam is removed from the liquid crystal material and the inner walls of the container, and the inner space of the LCD panel is made to a vacuum state.
A liquid crystal inlet of the LCD panel is dipped into the liquid crystal material of the container under the vacuum state, and then the pressure inside the chamber is made to an atmospheric pressure. Thus, the liquid crystal material is injected to the inside of the LCD panel through the liquid crystal inlet by the pressure difference between the inside of the LCD panel and the chamber.
A method for fabricating an LCD device by the liquid crystal injection method has the following disadvantages. After cutting the two substrates into unit LCD panels, the vacuum state is maintained between the two substrates. In this state, the liquid crystal inlet is dipped into the container of the liquid crystal material. Thus, it requires a long time to inject liquid crystal, thereby lowering the manufacturing yield.
Also, when forming the large-sized LCD device, it is impossible to completely inject the liquid crystal material to the inside of the LCD panel, thereby causing the defects.
Further, the liquid crystal injection method requires a complicated process and spends a long time. That is, it is necessary to provide several equipments for injection of liquid crystal, thereby requiring a large space.
To overcome these problems of the liquid crystal injection method, the liquid crystal dropping method is developed, in which liquid crystal is dropped on any one of two substrates, and the two substrates are bonded to each other. In the liquid crystal dropping method, before bonding the two substrates to each other, the appropriate amount of liquid crystal is dropped on any one of the two substrates. After completing the dropping of liquid crystal, the two substrates are bonded to each other.
FIG. 2 is a photograph illustrating a gravity defect in an LCD device according to the related art. FIG. 3 is a cross sectional view along I-I′ of FIG. 2.
Referring to FIG. 2, the gravity defect generates in a lower edge of the LCD panel which is adjacent to the ground. When the LCD panel stands vertically, liquid crystal flows downward by gravity. Thus, the lower edge of the LCD panel is swollen, whereby a cell gap corresponding to the lower edge of the LCD panel increases, thereby generating spots.
As illustrated in FIG. 3, when cutting the LCD panel 10, a column spacer 20 may be apart from the first substrate 1 due to the swollen liquid crystal in the lower edge of the LCD panel 10. Especially, if the LCD panel 10 stands vertically when providing the excessive amount of liquid crystal, the liquid crystal flows to the lower edge of the LCD panel which is adjacent to the ground, whereby the lower edge of the LCD panel is relatively swollen.
At this time, a sealant pattern 25 is formed in a peripheral region of the LCD panel 10, and then the first and second substrates 1 and 2 are bonded to each other by the sealant pattern 25. In this case, a liquid crystal layer 3 is formed with the liquid crystal dropped between the first and second substrates 1 and 2. In the liquid crystal layer 3, a cell gap in the portion having no gravity defect is different from a cell gap in the portion having the gravity defect. When driving the LCD device, the portion having the gravity defect is displayed as a blurred image.
FIG. 4 is a view illustrating a polarizer corresponding to the LCD panel according to the related art. Referring to FIG. 4, the polarizer 30 corresponding to the LCD panel has the same retardation value Δnd on the entire surface.
When the LCD panel stands vertically, the liquid crystal flows down. Thus, the lower edge of the LCD panel swells, which is displayed as the blurred portion, thereby deteriorating the picture quality. The gravity defect is generated when the liquid crystal is excessively dropped on the substrate. Even though the LCD panel is maintained at room temperature or high temperature, the gravity defect may nonetheless be generated.
Thus, as an example, the related art LCD device has the disadvantage of when the LCD panel stands vertically after excessive dropping of the liquid crystal on the substrate, the liquid crystal flows downward, whereby the lower edge of the LCD panel becomes swollen, which is referred to as the gravity defect. In this case, the LCD panel having the gravity defect may result in a blurred image, lowering the picture quality.

Polarizer for compensation of gravity defect in liquid crystal display device


The invention concerns a transmitter-receiver device (A, B) which comprises a receiver unit (RXA) arranged to receive light and optical signals from a transmitter unit (TXA) arranged to transmit light and optical signals. The device also comprises a supervising unit (CUA) which prevents the transmitter unit (TXA) from continuously transmitting light when the supervising unit (CUA) detects that the receiver unit (RXA) does not receive light. The supervising unit (CUA) is arranged to, when it detects that the receiver unit (RXA) does not receive light, change to a test mode where the transmitter unit (TXA) is controlled to intermittently transmit short light pulses the supervising unit has an output (109) where a status signal indicates whether the transmitter-receiver device is in said test mode. The invention also concerns a communication system which comprising at least two such transmitter-receiver devices.

The present invention concerns a transmitter-receiver device which may be used to transfer information optically. Such a transmitter-receiver device may form part of a communication system for bidirectional transfer of optical signals. The invention also concerns such a communication system.
FIG. 1 shows schematically an example of a bi-directional communication system according to the prior art for transferring optical signals. The system comprises a first transmitter-receiver device A with a receiver unit RXA and a transmitter unit TXA. The transmitter-receiver device A communicates with a similar transmitter receiver device B. Also the transmitter-receiver device B thus comprises a transmitter unit TXB and a receiver unit RXB. The transmitter unit TXB transmits optical signals over a first optical fibre F1 to the receiver unit RXA. In a similar manner, the transmitter unit TXA transmits optical signals over a second optical fibre F2 to the receiver unit RXB. In such a system, the light that is transmitted from the respective transmitter unit TXA, TXB often has an essentially constant average power, i.e. light is normally transmitted all the time. The information transfer is carried out through a suitable modulation of this light signal.
The receiver units RXA, RXB may have an output UA, UB, respectively, which for example may assume two logical values depending on if the optical power received in the receiver units RXA, RXB exceeds a certain value. This output UA, UB may for example be connected to an indicator IA, IB, for example in the form of a light emitting diode. Such an indicator IA, IB may for example emit light if the respective receiver unit RXA, RXB receives light. In such a manner, the respective indicator IA, IB may indicate that the connection over the fibre F1, F2 works. The signal from the output UA or UB may also be connected to a network management system NMS. Such a network management system NMS supervises the communication system and makes it possible to, from a completely different position than where the transmitter-receiver devices A and B are located, supervise whether the bi-directional communication system works. The lines 131, 133, 135, and 137 are intended to transfer information carrying signals, for example as electric signals, to and from the transmitter and receiver units RXA, TXA, TXB, and RXB.
In the system according to FIG. 1, for example the transmitter-receiver device B may be arranged in a home and the second transmitter-receiver device A may constitute a centrally located device which transmits signals to the home and receives signals from the home. In order to supervise the system it is desirable to connect the device B to the network management system NMS. If, for example, the device B is positioned in a home or in an office, this device often has no other connection out from the home or the office than via the optical fibres F1 and F2. It is actually conceivable to connect the device B to a network management system via the fibre F1. However, it is relatively expensive and complicated to, in addition to the normal information signals, also transmit signals concerning the network management on the same fibre F1. Furthermore, this network management does not work in case of a breakage of the fibre F1. Since the network management system NMS is intended to supervise the function of the network, it is desirable that this supervision works also in case an error occurs in the communication between the devices A and B. It is, of course, conceivable that the network management system NMS may supervise the device B via another line than via F1 or F2, for example in the home there may be a telephone modem, over which this supervision takes place. This constitutes, however, a complicated solution for transferring signals to the network management system NMS. It is, of course, also possible that a person goes to the device B in order to personally check if, for example, the indicator IB is lit. This may possibly be acceptable within, for example, an office where the distance to B may be short. However, it becomes much more complicated to send a person to the device B if this device is located at a long distance from the position where the person normally is.
As a background to the present invention, also so-called eyesafe fibre communication systems should be mentioned. A problem with fibre communication systems is that the light intensity which is transmitted over the fibres may be relatively high. If, for example, a fibre is broken and if somebody looks into the fibre, damages of the eye might occur. If a fibre is broken or damaged, it is therefore desirable to cut off the light signal which is transmitted over this fibre. For example U.S. Pat. No. 5,136,410 describes such a system.
With reference to FIG. 1 it will now briefly be described how an eye-safe system may work. Suppose that a breakage takes place of the fibre F1. The output UA thereby indicates that no light is received in the receiver unit RXA. A supervising unit (not shown in FIG. 1) may then cut off the transmission of light from the transmitter unit TXA. At the receiver unit RXB it is thereby detected that no light is received. Another supervising unit in connection to the device B thereby immediately cuts off the transmission of light from the transmitter unit TXB. Thereby, no harmful light exists on the broken fibre F1. In order to check if the connection via the fibre F1 works again, the respective transmitter unit TXA, TXB often transmits short light pulses at regular intervals. These light pulses are so short that they are not harmful to the eye. When one receiver unit RXB receives such a light pulse, a similar light pulse is immediately transmitted by the transmitter unit TXB. As long as the breakage of the fibre F1 is the case, the receiver unit RXA does not detect any such light pulse. If, however, the fibre F1 works again, the receiver unit RXA will detect such a response pulse from TXB immediately after TXA having transmitted a pulse to RXB. The connection thus works again and the respective transmitter unit TXA, TXB may now continuously transmit light. The time between the light pulses in such a safety system is usually quite long, for example U.S. Pat. No. 5,136,410 mentions that the time between these pulses is about 49 seconds.

This patent is subject to a terminal disclaimer.

Transmitter-receiver device and a communication system


A tool for limiting a cut on an impeller having a shaft and vane is provided. The tool includes a shield member having a sidewall, a top, and an inner cavity. The tool also includes a first cut opening extending through the hub sidewall to the shield member inner cavity, the shield member configured to matingly receive the impeller shaft into the shield member inner cavity and position at least a portion of the impeller shaft proximate the at least one cut opening to expose the portion of the impeller shaft for grinding.

Jet engines (also called gas turbine engines) are generally designed and built robustly and safely. Nonetheless, these well-designed engines may need to undergo periodic maintenance and/or repair. Such maintenance and repair operations may include partial or complete disassembly of the engine, and removal, repair, or replacement, of one or more components within the engine. Some of the components may be installed in the engine according to relatively tight tolerances. Although these same components may be manufactured to within design specification tolerances, manufacturing variation may still exist. Thus, engine re-assembly following maintenance and/or repair may include instances in which these variations are accounted for by, for example, cutting and/or reconfiguring portions of the pre-manufactured replacement parts.
For example, in the compressor section of a jet engine, it is desirable to have balanced axial rotation of the compressor impeller. Occasionally, when a compressor impeller is replaced, the replacement impeller may rotate in an imbalanced manner. Thus, in such cases, typically, portions of the impeller shaft are either cut or grinded away. At times, the grinding tool operator may inadvertently grind too much of the impeller shaft or may miscut the impeller by cutting or grinding the impeller vanes. Generally, when a misgrind or miscut is made on an impeller, the compressor impeller is rendered non-serviceable and is typically discarded.
Therefore, there is a need for an apparatus that addresses one or more of the above-noted drawbacks. An apparatus that allows accurate grinding and cutting of the impeller shaft for rotational balance within a jet engine is desirable. It is also desirable for the apparatus to be inexpensive and easy to use. The present invention addresses one or more of these needs.


A sealing-enhancing coating for a gasket or a portion of a gasket includes flaky particles of chemically exfoliated vermiculite, at least 90% by weight of the particles having a thickness of no more than 30 microns, and no dimension greater than 1 mm. The particles form 10 to 90 wt. % of the coating. The coating also includes 50 to 10 wt. % of an organic polymer binder which when formed into a film 1 mm or less in thickness and heated to 300° C. in free air for 24 hours either does not decompose or decomposes leaving a residue of at least 20% by weight of film.

1. Technical Field
This invention is concerned with a gasket coating. In particular, the invention is concerned with a gasket coating for application to a surface of a gasket to provide improved sealing by filling small cracks and fissures in the surface of the gasket and/or of the member against which the gasket seals.
2. Related Art
Gaskets are used for sealing between two members, e.g. two portions of the exhaust system of an internal combustion engine, and provide a seal around a passage which passes from one member to the other. Accordingly, a gasket has to be resilient in order to press against the members and provide a fluid-tight seal. In the case of an exhaust gasket, the seal is to prevent escape of exhaust gases and entry of air. The resilience can be provided by utilising a relatively thick layer of resilient material such as a resilient rubber-based material or graphite but, where high temperatures (above 300.degree. C.) are experienced such as in an exhaust system, many resilient materials would degrade and are not commonly used. Instead, the gasket comprises a sheet of metal, e.g. stainless steel, which is formed into resilient ridges (called "beads") which provide the seal. Thus, when such a gasket is clamped between two members, the clamping force compresses the beads which are resiliently deformed and press against the members along the lines of the beads. However, such gaskets normally do not provide as good a seal as is desirable because the beads are unable to enter into small cracks and fissures in the members so that gases and liquids can escape past the beads. It is known, in gaskets not utilised at such high temperatures as are experienced by exhaust gaskets, to provide metal beads with a thin coating (typically less than 200 microns in thickness) of a sealing-enhancing coating which will deform under clamping pressure to fill cracks and fissures. Known sealing-enhancing coatings, however, degrade at higher temperatures so that they cannot be used on, e.g., exhaust gaskets for internal combustion engines.

Gasket coating containing chemically exfoliated vermiculite


A phase locked loop circuit for extracting a clock component from an input signal and generating a phase locked clock signal. Operates to detect a partial loss of the input signal and keep the input signal of a low-pass filter that is one component of the circuit zero. The clock signal is controlled to be far from an originally assumed signal while a partial loss of the input signal is detected. Hence, the pull-in operation of the PLL is expedited after the normal clock signal can be extracted.

1. Field of the Industrial Application
The present invention relates to a phase locked loop (PLL) circuit and a signal reproducing apparatus for reproducing data with a clock signal supplied by the PLL circuit.
2. Description of the Related Art
When reproducing digital data recorded on a recording medium such as an optical disk, a magnetic disk or a magnetic tape, it is necessary to generate a reproduction clock, that is, a so-called channel clock for pulling a channel bit from a signal read out of the recording medium. For generating a clock, in general, the PLL circuit is used. This PLL circuit may take an analog type or a digital type. The digital PLL circuit basically has the arrangement as shown in FIG. 1.
In FIG. 1, an input terminal 101 is inputted with a signal read from the recording medium such as the so-called EFM (Eight-Fourteen Modulation) signal. This EFM is a modulating system adopted by the so-called CD (compact disk), which operates to modulate 8-bit data into 14-channel bits according to the predetermined modulating rules. The modulated EFM signal includes inverted intervals (inter-edge intervals) in the range of 3T to 11T, where T is a channel bit period and contains a channel clock component.
The digital PLL circuit is arranged to have a phase comparator 102 being inputted with a signal from the input terminal 101, a low-pass filter (LPF) 103, and a variable frequency oscillator (VFO) 104. The output from the VFO 104 is taken as a PLL output clock PLCK at a terminal 105 as well as sent back to the phase comparator 102. The VFO normally uses a voltage controlled oscillator (VCO) for the analog PLL, while for the digital PLL, the VFO uses an oscillator arranged to change a frequency dividing ratio according to input phase error information, such as a number controlled oscillator (NCO).
In the foregoing arrangement, the phase comparator 102 operates to compare the PLL output clock PLCK with the input signal. Then, the compared result is sent to a digital LPF 103 through which a dc signal corresponding to the phase difference is taken out. Based on the phase difference signal, the oscillating frequency of the VFO 104 is controlled so that the resulting PLL output clock PLCK takes synchronization with a channel clock of the input signal (for example, EFM signal).
The phase comparator 102 is arranged as shown in FIG. 2, for example. An input signal (for example, EFM signal) at the input terminal 101 is sent to a first-stage register 121 that is connected in series with a second-stage register 122 and an Exclusive OR gate 123. The output from the register 121 is sent to the register 122 and the Exclusive OR gates 123 and 124. The Exclusive OR gate 124 is inputted with the output from the register 122. The registers 121 and 122 are driven on the PLL output clock PLCK from the terminal 105. The register 122 is inputted with the inverted clock PLCK given by an inverter 125. The output from the Exclusive OR gate 123 is sent to an enable terminal EN of a phase difference counter 126. The output from the gate 123 is inverted by an inverter 128 and then sent to a load control terminal LD. The output from the phase difference counter 126 is sent to a phase register 127. The phase difference counter 126 and the phase register 127 are driven on a master clock MCK sent from a terminal 106. The output from the Exclusive OR gate 124 is sent to a clock terminal of the phase register 127 as a phase register clock. The phase difference data is taken from the phase register 127 through a terminal 107 and then is sent to the LPF 103.
Then, the operation of the phase comparator shown in FIG. 2 will be described with reference to signal waveforms of components shown in FIGS. 3A to 3F.
In a case that the terminal 101 is inputted with the EFM signal as an input signal shown in FIG. 3A and the terminal 105 is inputted with the PLL output clock PLCK shown in FIG. 3B, the Exclusive OR gate 123 operates to output a "H" (High-level "1") signal between a rising time t.sub.1 of the EFM signal and a rising time t.sub.2, of the PLL output clock PLCK, during which the phase difference counter 126 continues to do a counting operation and then outputs a count signal as shown in FIG. 3D. The Exclusive OR gate 124 operates to output a signal that keeps at high level between the rising time t.sub.2 and the falling time t.sub.3 of the PLL output clock PLCK as shown in FIG. 3E. The phase register 127 is inputted with the output from the phase difference counter 126 on the rising timing t.sub.2 as shown in FIG. 3E, so that the output from the phase register 127 is switched as shown in FIG. 3F at the time t.sub.2.
A value to be loaded as initial data from the terminal 108 to the phase difference counter 126 is initialized to such a value as making the counter output value zero when the phase error is zero. The value is shifted to a negative side by a count value corresponding to a half of a period of the PLL output clock PLCK. The master clock MCK supplied to the terminal 106 is normally set as such a frequency as being several times or more as large as the PLL output clock frequency.
The phase difference data from the terminal 107 of the phase comparator as shown in FIG. 2 is sent to the digital LPF as shown in FIG. 4.
The digital LPF shown in FIG. 4 is arranged to have a register 131 on an input side and registers 132 and 133. That is, the phase difference data supplied through the terminal 107 is sent to the register 132 and an adder 136 through the register 131. Then, the output from the register 132 is multiplied by a coefficient from the terminal 135 and then is sent to the adder 136. The output from the adder 136 is sent to an adder 137, the output of which passes through a register 133 and then is multiplied by a coefficient from the terminal 139 through the effect of a multiplier 138. Then, the multiplied result is fed back to the adder 137, and the output of the register 133 is taken through a terminal 140 as an LPF output. These registers 131, 132 and 133 are driven at a filter clock sent from the terminal 110. This clock corresponds to both edges of the PLL output clock PLCK, for example.
The digital LPF operates to take a low-pass component of the phase difference data or the so-called dc component and then apply it to the VFO 104 shown in FIG. 1 as a control voltage.
In case some defects are caused on a recording medium such as a disk by impairments or fingerprints, the edges of the EFM signal read from the medium may be dropped over such a long time as several hundreds micro seconds.
The phase register 127 of the phase comparator shown in FIG. 2 operates to detect the edge of the EFM signal inputted by the registers 121 and 122 and update the phase data as a clock signal. Hence, the drop of the edge of the input signal inhibits to update the phase difference data of the phase register 127. As a result, the phase difference data immediately before the edge of the input signal is dropped is held as it is. The signal level lowered near the defect disallows the edge to be normally detected. Hence, it is more likely that the output from the phase difference counter 126 and the phase difference data from the phase register are greatly disturbed.
Hence, the LPF shown in FIG. 1 is inputted with a value greatly shifted from a center value for a long time, so that the LPF keeps a dc value inside of itself and supplies a dc value. As a result, the oscillating frequency of the VFO 104 shown in FIG. 1 is greatly shifted from the center value.
Afterwards, an optical pickup is departed from the defect of the medium so that the edge of the EFM signal can be properly obtained. Then, the PLL circuit performs a pulling operation. Since the LPF has a great time constant, the PLL circuit disadvantageously needs a long time for pulling in the phase of the signal if the dc value is stored in the filter.

Phase locked loop circuit and reproducing apparatus provided with thereof


A semiconductor laser device capable of improving heat dissipativity, simplifying the fabrication process and improving the fabrication yield is obtained. This semiconductor laser device comprises a semiconductor layer formed on an emission layer while constituting a convex ridge portion, a current blocking layer consisting of a semiconductor formed to cover at least the side surfaces of the ridge portion, a first metal electrode formed to be in contact with the upper surface of the ridge portion and convex support portions arranged on both sides of the ridge portion at a prescribed interval from the ridge portion.

1. Field of the Invention
The present invention relates to a semiconductor laser device and a method of fabricating the same, and more particularly, it relates to a semiconductor laser device having a convex ridge portion and a method of fabricating the same.
2. Description of the Background Art
A semiconductor laser device having a convex ridge portion serving as a current path is known in general. For example, Japanese Patent Laying-Open No. 2002-252421 discloses this type of semiconductor laser device.
FIG. 50 is a sectional view for illustrating a conventional semiconductor laser device having a ridge portion. The structure of the conventional semiconductor laser device having a ridge portion is described with reference to FIG. 50.
In the conventional semiconductor laser device having a ridge portion, an n-type buffer layer 202 of n-type GaInP, an n-type cladding layer 203 of n-type AlGaInP, an emission layer 204 including a multiple quantum well (MQW) active layer of GaInP/AlGaInP and a p-type first cladding layer 205 of p-type AlGaInP are successively formed on an n-type GaAs substrate 201, as shown in FIG. 50.
A mesa (trapezoidal) ridge portion constituted of a p-type second cladding layer 206 of p-type AlGaInP, an intermediate layer 207 of p-type GaInP and a contact layer 208 of p-type GaAs is formed on a prescribed region of the upper surface of the p-type first cladding layer 205. This ridge portion is formed in a striped (elongated) shape.
Current blocking layers 209 prepared by stacking n-type AlInP layers and n-type GaAs layers are formed to cover the upper surface of the p-type first cladding layer 205 and both side surfaces of the ridge portion while exposing only the upper surface of the ridge portion (contact layer 208). A p-type cap layer 210 of p-type GaAs is formed to cover the exposed upper surface of the ridge portion and the upper surfaces of the current blocking layers 209.
A p-side electrode 211 is formed on a portion of the p-type cap layer 210 around the aforementioned ridge portion. An n-side electrode 212 is formed on the back surface of the n-type GaAs substrate 201.
A process of fabricating the conventional semiconductor laser device having a ridge portion is now described with reference to FIG. 50. First, the n-type buffer layer 202 of n-type GaInP, the n-type cladding layer 203 of n-type AlGaInP, the emission layer 204 including the multiple quantum well (MQW) active layer of GaInP/AlGaInP, the p-type first cladding layer 205 of p-type AlGaInP, the p-type second cladding layer 206 of p-type AlGaInP, the intermediate layer 207 of p-type GaInP and the contact layer 208 of p-type GaAs are successively formed on the n-type GaAs substrate 201 by MOVPE (metal organic vapor phase epitaxy).
Then, SiO2 layers (not shown) are formed on the contact layer 208 by photolithography and etching at a prescribed interval. The SiO2 layers are employed as masks for etching the p-type second cladding layer 206, the intermediate layer 207 and the contact layer 208, thereby forming the mesa (trapezoidal) ridge portion consisting of the p-type second cladding layer 206, the intermediate layer 207 and the contact layer 208 in the striped shape on the central portion of the p-type first cladding layer 205.
Then, an SiO2 layer (not shown) formed on the ridge portion is employed as a mask for growing the current blocking layers 209 consisting of the n-type AlInP layers and the n-type GaAs layers to cover the upper surface of the p-type first cladding layer 205 and both side surfaces of the ridge portion. Thereafter the SiO2 layer (not shown) is removed from the ridge portion.
Thereafter the p-type cap layer 210 of p-type GaAs is formed by MOVPE to cover the exposed upper surface of the ridge portion and the upper surfaces of the current blocking layers 209. The p-side electrode 211 is formed on the portion of the p-type cap layer 210 around the aforementioned ridge portion by the lift off method.
The back surface of the n-type GaAs substrate 201 is etched for thereafter forming the n-side electrode 212 on this back surface. The conventional semiconductor laser device having a ridge portion is formed in the aforementioned manner.
FIG. 51 is a sectional view illustrating the conventional semiconductor laser device shown in FIG. 50 in a state mounted on a submount 251 in a junction-down system. According to the junction-down system, the semiconductor laser device is mounted on the submount 251 from the surface closer to the emission layer (active layer) 204. Referring to FIG. 51, a projecting portion of the p-side electrode 211 provided on the surface of the aforementioned conventional semiconductor laser device is directed downward and mounted on a metal film (electrode) 252 of the submount 251 through a welding material 253 consisting of a low melting point metal such as solder. In this case, the submount 251 also has a function of a heat sink absorbing heat of the semiconductor laser device and dissipating the same outward in general. Therefore, the heat generated from the semiconductor laser device is dissipated by the submount 251 from the aforementioned ridge portion through the p-type cap layer 210, the p-side electrode 211, the welding material 253 and the metal film 252.
When the aforementioned conventional semiconductor laser device is mounted on the submount 251 in the junction-down system, however, the heat generated from the semiconductor laser device is dissipated by the submount 251 through the p-type cap layer 210 of p-type GaAs having lower thermal conductivity than the welding material 253 of a low melting point metal such as solder, to disadvantageously reduce heat dissipativity. Therefore, the conventional semiconductor laser device is disadvantageously reduced in reliability (lifetime).
In the aforementioned conventional semiconductor laser device, further, three crystal growth steps must be carried out in total by MOVPE for growing the layers from the n-type buffer layer 202 to the contact layer 208, the current blocking layers 209 and the p-type cap layer 210 respectively. Consequently, the fabrication process for the semiconductor laser device is disadvantageously complicated.
When mounted on the submount 251 in the junction-down system, further, the aforementioned conventional semiconductor laser device is so easily inclined with respect to the submount 251 that the welding material 253 such as solder adheres to the side end surfaces of the inclined semiconductor laser device to easily electrically short the n-type semiconductor layers 202 and 203 and the p-type semiconductor layers 205 to 208 holding the emission layer 204 including the MQW active layer therebetween. Consequently, the fabrication yield is disadvantageously reduced.
When the aforementioned semiconductor laser device is mounted on the submount 251 in the junction-down system, in addition, only the projecting portion of the p-side electrode 211 comes into contact with the metal film 252 of the submount 251, to disadvantageously easily apply stress to the ridge portion located under the projecting portion of the p-side electrode 211. When stress is applied to the ridge portion, the operating current and the operating voltage are disadvantageously increased. When stress is applied to the ridge portion, further, the intensity ratio of polarization between a TE mode having an electric field component in a direction parallel to the emission layer 204 including the MQW active layer and a TM mode having an electric field component in a direction perpendicular to the emission layer 204 (intensity of TE mode/intensity of TM mode: polarization ratio) is disadvantageously reduced in light emitted from the semiconductor laser device.

Semiconductor laser device and method of fabricating the same


A web scaping system configured with artificial intelligence and image object detection. The system processes a web page with a neural network to perform object detection to obtain structured data, including text, image and other kinds of data, from web pages. The neural network allows the system to efficiently process visual information (including screenshots), text content and HTML structure to achieve good quality and decrease extraction time.

Software that extracts structured information from the web automatically is conventionally handled by creating custom crawlers ("spiders") for each website being crawled using manually specified rules. ScrapingHub is a creator and maintainer of the most popular open-source framework for creating such spiders (Scrapy). While this approach works, conventional crawlers require development and maintenance efforts for each website, which is slow, costly, and does not scale well to a large number of websites.

System and method for a web scraping tool and classification engine


A system for managing messages so that messages with redundant contents need not be reviewed by a user. Techniques of the invention monitor electronic messages received by a user and determine whether the received electronic messages are related to pending electronic messages for the user, such as by being part of the same message thread. Messages with redundant contents among the related messages are then identified, and the messages with redundant contents are managed so that the user need not review the contents. The messages with redundant contents can be managed by creating a new message which includes the unique contents of each of the identified messages but at most a single copy of the redundant contents. After the new message is created, the identified messages can then be indicated to be redundant in light of the newly created message in one or more ways, such as by deleting the identified messages or by altering the visual indicators of the identified messages presented to the user. Alternately, the messages with redundant contents can be managed by deleting the redundant contents from the identified messages, or by altering the manner in which the redundant contents are presented to allow for easy identification by the user.

The present invention relates generally to communicating via electronic messages, and more particularly to identifying and managing related electronic messages.
Electronically-communicated messages (xe2x80x9celectronic messagesxe2x80x9d or xe2x80x9celectronic communicationsxe2x80x9d) such as email, voicemail, paging messages, and transmitted documents have become increasingly popular and pervasive in recent years. The ability to send an electronic message to multiple recipients provides for quick and efficient communication, and the use of electronic messages has become common in business settings.
While electronic messages can be specified in a variety of formats, a typical electronic message will include substantive contents to be conveyed (e.g., text and/or images) as well as a preceding header with various identifying information about the message. For example, a header of an electronic email message might include an identification of the sender and of the recipients, as well as a subject for the message. Headers can also include information such as the size of the message, a specification of the encoding used for the message (e.g., a particular compression algorithm), a specification of the transmission protocol for which the message was created (e.g., TCP/IP), or a unique identifier for the message.
While a user can create and send a message independent of any other messages, messages are often part of a message thread. A message thread is a group of messages that are related to each other, such as when one message is a response to (e.g., a reply to or a forwarding of) another message. Messages in the same message thread will typically share various common message information, such as related subjects or common message content. For example, a reply email or voicemail will often include the contents of the original message as well as additional contents specific to the reply, and the subject line of a reply or forwarded email will often include the original subject line along with a relation indicator such as xe2x80x9cRE:xe2x80x9d or xe2x80x9cFW:xe2x80x9d respectively.
Consider, for example, the following situation in which co-workers send a series of emails that are part of a single message thread back and forth to each other, and each response message contains the contents of the message being responded to as well as additional unique content. Worker A first sends message 1 to workers B and C and to supervisor D. Worker B responds to message 1 with response message 2 sent to A and D, and worker C responds to message 1 with a distinct response message 3 sent to A and D. Thus, supervisor D has received message 1, message 2 which includes the contents of message 1 as well as additional contents, and message 3 which includes the contents of message 1 as well as additional contents.
While message threads can provide various benefits, receiving message thread messages can also create various problems. For example, a recipient of multiple message thread messages will often receive multiple messages that include common content. In the example above, supervisor D received the contents of message 1 in three different messages. After the contents of message 1 has been received the first time (e.g., from receiving message 1), those contents become redundant for that message recipient when they are included in the contents of other received message thread messages (e.g., such as response messages 2 and 3).
Current mechanisms for managing pending messages for a user create problems with respect to message thread messages with redundant contents. Pending messages for a user include those messages which have been received but not yet reviewed, as well as those messages which have been reviewed and retained. When a user has received multiple messages that are part of a common message thread, current message management mechanisms store and present each such message to the user. However, when the pending messages for a user include messages with contents that are redundant in light of the contents of other pending messages, various inefficiencies result. For example, extra computer resources are needed for the storage and presentation of the redundant contents, and extra time is needed by the user to review each message and to determine what contents are new and what contents are redundant.
The present invention provides a method and system for managing messages so that messages with redundant contents need not be reviewed by a user. Techniques of the invention monitor electronic messages received by a user and determine whether the received electronic messages are related to pending electronic messages for the user, such as by being part of the same message thread. Messages with redundant contents among the related messages are then identified, and the messages with redundant contents are managed so that the user need not review the contents. The messages with redundant contents can be managed by creating a new message which includes the unique contents of each of the identified messages but at most a single copy of the redundant contents. After the new message is created, the identified messages used to create the new message can then be indicated to be redundant in light of the newly created message in one or more ways, such as by deleting the identified messages or by altering the visual indicators of the identified messages presented to the user. Alternatively, the messages with redundant contents can be managed by deleting the redundant contents from the identified messages, or by altering the manner in which the redundant contents are presented to allow for easy identification by the user.
In one aspect of the invention, multiple electronic messages sent to the user are identified, at least two of the electronic messages are determined to have contents that each include the contents of another electronic message, and a new electronic message is generated containing the contents of the determined electronic messages in such a manner that the new electronic message contains only a single copy of the contents of the other electronic message.

Method and system for managing related electronic messages


A process for simultaneously exchanging material and for exchanging heat, material change being effected between a gas phase and at least one liquid phase by contact and passage in opposite directions of the gas phase and of the at least one liquid phase and heat exchange being effected between a compartment (I) and another compartment (II). In compartment (I) a plurality of spacer plates defining material exchange passages are arranged and the material exchange is effected by causing the at least one liquid phase to flow over a substantially vertical or inclined wall of a corrugated spacer plate having perforations and by causing at least a fraction of the gas phase to traverse simultaneously said perforations in a substantially ascending direction to contact said at least one liquid phase. The heat exchange is effected by circulating a heat exchange fluid in the compartment (II) which has a common wall with the compartment (I).

The invention relates to a process and a device allowing material and heat to be transferred between a gas phase and one or two liquid phases and simultaneously allowing heat exchanges with another fluid.
This invention employs a device having several compartments delimited in particular by a stack of several flat plates, each plate being spaced apart from the next plate. This separation space may be occupied by corrugated plates. This type of arrangement is already used to carry out heat exchanges. The fluids circulate in passages formed between two adjacent plates. These passages are alternate and allow co-current circulation between the hot flow and the cold flow, or counter-current circulation. This type of exchanger improves the heat transfer coefficient but does not allow material to be transferred.
In general, the technology developed for making such heat exchanges is widely known. As stated, these exchangers are composed of a stack of stamped sheet metal. The space between the plates is filled with spacers composed of baffles formed directly in the sheet metal by stamping, or by spacer plates called waves, made of straight metal.
The spacer waves maintain a uniform spacing between the plates, and some of them create a secondary exchange surface. In general, the spacer waves increase the rate of flow, and improve the ability of the system to withstand pressure. All these metal sheets are joined to each other either by welding or by brazing, which provides a good seal between the plates but makes it practically impossible to clean the assembly mechanically, or by bolting which makes it necessary to use gaskets between the plates to prevent communication between the two fluids and leakage to the outside. Whatever the type of these systems, they all improve, to a greater or lesser degree, the specific exchange surface and the heat transfer coefficient.
All the inlets to the compartments receive the same fluid (for example, hot fluid), communicate with each other, and are in communication with a box called the exchange header. This box is joined to the assembly either by welding or by bolting with a gasket. The same type of assembly is performed for the outlet connections. Thus, in general, an exchanger supplied with two different fluids has four headers, two inlet headers, one for each fluid, and two outlet headers, one for each fluid.
The prior art, U.S. Pat. No. 3,568,462, also teaches circulating a film of condensed liquid flowing downward and a vapor phase flowing upward in compartments through a perforated horizontal plate or wave.
However, such a device has its drawbacks. It generates a substantial pressure loss since the fluids are forced to pass through horizontal plates. Such an arrangement requires the size of the perforations to be increased, to the detriment of the quality of the gas-liquid contact, the flowrates treated, and the mechanical rigidity of the device.

Process and device for the simultaneous transfer of material and heat


A cochlear implant system including primary and secondary coils of wire for transmitting electromagnetic energy between the primary and secondary coils, wherein at least one of the primary and secondary coils are wound with turns of wire that are distributed radially and not concentrated at a single circumference so as to enhance the magnetic coupling coefficient of the primary and secondary coil systems.

One possibility for transcutaneously providing an implanted stimulator with power and information is to transmit rf-power via an inductively-coupled coil system. Such a coil system consists of a primary coil which is outside the body and a secondary coil implanted with the stimulator. When facing each other, the primary and secondary coils form a transformer which allows energy transfer from a transmitter powering the primary coil to the implanted stimulator. For example, cochlear prostheses systems utilize inductively coupled coils for power and data transmission. The diameters of primary and secondary coils for such applications are typically between 15 and 30 mm, and the coil separation is typically between 4 and 15 mm.
The minimum geometric size of the coils in general is determined by the distance between the coils. To achieve a high amount of inductive coupling, the distance between the coils has to be sufficiently small compared to the coils' diameters. A sufficiently high inductive coupling is a necessary condition to achieve a high power transfer efficiency. If the coupling is too low, a higher current in the primary coil has to be used to provide the same output from the secondary coil. Thus more power is wasted in the primary coil due to ohmic losses.

Device for transferring electromagnetic energy between primary and secondary coils

MED-EL Elektromedizinische Gerate Ges.M.B.H.


The airbag apparatus includes an airbag folded and housed in a housing. The airbag includes an outer bag constituting an outer wall of the airbag and an inner bag disposed inside the outer bag. The inner bag includes an outlet port supplying inflation gas into the outer bag and an arm inflatable into a tapered bag contour. The arm holds down a peripheral defected region of the outer bag defected from the housing onto a top plane of a ring of a steering wheel all the while that the inner bag remains completely inflated at the operation of the airbag apparatus.

1. Field of the Invention
The present invention relates to an airbag apparatus mountable on a vehicle and including an airbag inflatable with inflation gas and protruding from a housing where the airbag was folded and housed. More particularly, the present invention relates to an airbag apparatus whose airbag includes an outer bag and an inner bag disposed inside the outer bag, and which is suitably used for a steering wheel or a front passenger's seat.
2. Description of Related Art
A conventional airbag apparatus mountable on a vehicle includes an airbag inflatable with inflation gas and protruding from a housing where the airbag was folded and housed. As shown in JP 9-220995 A and in JP 2001-080440 A, such an airbag is attached to the housing at a periphery of its opening for admitting inflation gas. The airbag includes an outer bag constituting an outer wall of the airbag and an inner bag disposed inside the outer bag over the inlet opening. The inner bag is provided with an outlet port for allowing the inflation gas fed from the inlet opening to flow out into the outer bag.
The outlet port of the inner bag is used to redirect the inflation gas flowing out into the outer bag in order to control an inflated contour of the outer bag from the initial stage until the completion of inflation. For example, the outlet port is used to control the contour of the outer bag such that the deployment of the outer bag to an abdomen of a driver is promoted. That is, the inner bag of the airbag helps redirect the inflation gas flowing out into the outer bag.
However, there has been a room for improvement in conventional airbag apparatuses in inflating the outer bag without allowing a region of the outer bag deployed proximate the housing to float from members disposed around the housing during the course of inflation.
The floating of the outer bag from the members disposed around the housing is likely to cause a swaying motion of the outer bag where the outer bag floats from the members disposed around the housing and falls back to bump against the members repeatedly during the course of inflation. In the floated state, the outer bag being inflated is not supported by the members disposed around the housing, which makes it difficult for the outer bag to secure an enough reaction force for exerting cushioning property for receiving an occupant. On the other hand, if the outer bag engages the occupant in a thickening phase during the swaying motion, the bag may press the occupant unduly.


Concentrated suspensions of smectite clays are obtained as either relatively “thin” or highly shear-thinning slurries that are easy to pump, by adding one or more of certain cationic polymers whose weight average molecular weight, Mw, is 50,000 or higher. It was found during the course of the invention that a cationic polymer with an Mw of 10,000 did not work, while the same polymer with a bimodal Mw of 50,000 and 30,000 worked satisfactorily. To achieve the full advantage of the present invention, the cationic polymer preferably has 1 to 10 milliequivalents of cationic charge per gram of the polymer, and more preferably 5 to 10 milliequivalents of cationic charge per gram of the polymer, and most preferably 6 to 8 milliequivalents of cationic charge per gram of the polymer.

Layered silicate materials such as the smectite clays are a class of inorganic particulate materials that occur as stacks of individual, planar silicate layers referred to as platelets in the clay literature. Examples of smectite clays include montmorillonite, bentonite, bidelite, hectorite, saponite, and stevensite. These clays are popular particulate gellants or thickeners for aqueous compositions.
Smectite clays also find use as a flocculation aid in wastewater treatment where the flocculant compositions used are generally solid admixtures of clay and other treatment reagents. These flocculant products, however, are excluded from those wastewater treatment scenarios where the facility is not equipped to handle any solid treatment reagent. Since smectite clay-water slurries turn into gels once the clay content exceeds a level that may be as low as in the range of 5-10% by weight, handling, especially pumping, of clay suspensions with high clay content may prove to be extremely difficult, if not impossible. Nevertheless, in order for it to be viable, any liquid product of clay-based flocculants should have clay content much exceeding the above range. The present invention reveals a method for achieving such desirable liquid products of smectite clay-based flocculants, and the compositions thereof.
The face-surfaces of the platelets of smectite clays bear anionic charges counterbalanced by exchangeable cations that remain electrostatically attracted to the anionic charge of the clay surface. The exchangeable cations are generally either sodium ions or calcium ions. Smectite clay is referred to as sodium or calcium clay, depending on the type of predominant counterions associated with the face-surfaces of the clay platelets. While the anionic charge on the platelet face-surfaces does not vary with pH, the electrical charge on the edge-surfaces of these clays, although anionic under alkaline pH, could be cationic under acidic pH.
Fundamentally, the formation of particulate gels is a manifestation of suspended colloidal particles forming a network structure that entraps and thus immobilizes the suspending medium. Clay-based gels may form when individual platelets or stacks of a few, e.g., 3-15, aggregated platelets (tactoids) engage in interparticle associations with their neighboring platelets. These particle-to-particle links result in a particulate structure pervading through the entire suspension-volume. Such interparticle associations are governed by the interplay between the attractive and repulsive forces that generally act between particles suspended in a liquid.
Clearly, the strength of particulate gels will depend on the number of interparticle associations in a given volume of the gel, implying that the greater the number-concentration of suspended particles, the stronger is the gel. Also, a dominance of the attractive interactions over the repulsive interactions, the likelihood of which increases with decrease in interparticle separation distance, is required for suspended particles to associate with their neighbors. An increase in number-concentration of particles will tend to reduce their separation distances, an effect that could be especially dramatic for planar particles since the separation distance between two adjacent platelets will vary along their lengths when their faces do not align in parallel configuration. Nonetheless, too strong an attraction between adjacent clay platelets may draw them into strong face-to-face association, minimizing the number-concentration of particles.
Considering the above, the key to making clay-based gels is to ensure that there is sufficient interplatelet repulsion for the clay platelets to exfoliate (delaminate) under shear, releasing a large number of platelets as individual platelets or tactoids having fewer stacked platelets, that would then be available to form a particle network. On the other hand, in order to form a voluminous network structure, the net interaction (the sum of attractive and repulsive forces) between the delaminated platelets must be such that they can remain "bound" (attracted) to their neighboring platelets without being drawn into strong face-to-face association. Accordingly, the gel-network may form if the delaminated platelets, while being separated from the surrounding platelets by as thick as possible an intervening layer of the suspending medium, reside in a minimum of free energy of interaction with the neighboring platelets. Albeit physically separated from their neighbors, the individual platelets are no longer free to move independently, being trapped in a free energy minimum, in effect producing a particulate structure, and therefore thickening or gelation. Yet another phenomenon that clay-based gels may form in aqueous compositions, is where clay platelets coagulate due to edge-to-face associations, forming the so-called "card-house" structure described in clay literature.
The sodium smectite clays exfoliate to a much greater extent than their calcium analogs. For this reason, the sodium smectite clays produce a significantly higher level of thickening as compared to the calcium smectite clays. Therefore, one way of having concentrated clay suspensions with high fluidity is to use calcium smectite clays. However, such dispersions, while possibly meeting the requirement of low viscosity, would not present a high number concentration of delaminated platelets, which may be desirable for having good flocculating properties during wastewater treatment.
The ability of clay platelets to bring about coagulation/flocculation of suspended debris particles in wastewater is related to a phenomenon that may be described as heterocoagulation (coagulation between dissimilar materials) between the clay platelets and the debris particles. Such heterocoagulation would occur when the physicochemical conditions of the wastewater are such that the interaction between the debris particles and the clay platelets is attractive, even though the interaction between the debris particles is repulsive, preventing these particles from coagulating. Another way to describe such a heterocoagulation process is to use the analogy of bridging flocculation by polymeric flocculants, as described in colloid literature: like polymeric flocculants, the clay platelets draw the suspended debris particles into flocculation by sticking to and thus bridging two or more debris particles simultaneously.
It may be expected that the aforementioned debris-clay coagulation process will be favored if the number concentration of clay platelets is high (i.e., if the clay platelets are highly delaminated or exfoliated, an effect that also promotes thickening induced by clay platelets) and/or if a strong clay platelet-debris particle attraction is brought into play. Accordingly, conflicting demands are faced in obtaining concentrated, non-viscous clay-suspensions where the clay platelets are sufficiently delaminated in order to have good flocculating power. Nevertheless, even when a large number of clay platelets have been released due to exfoliation, the platelets may be prevented from engaging into any association with the neighboring platelets if the interparticle repulsive forces greatly dominate over the attractive forces. Therefore, the key to attaining concentrated, but non-viscous clay-suspensions, without necessarily sacrificing good exfoliation of clay platelets, is to ensure that strong repulsive forces act between the platelets, superseding any attractive interplatelet forces that tend to bring about associations between the platelets. Most surfaces tend to acquire an anionic charge when wetted with an electrolyte or water. Also, the surface active agents (emulsifiers and dispersing agents) that are more commonly used in industrial applications are anionic, resulting in suspended particles in most wastewater streams that are generally anionic. So in the context of clay-based flocculants, it has been found that a way to increase the clay platelet-debris attraction is to render the surface of the clay platelets cationic through the adsorption of cationic species.
As described in colloid literature, ionic polymers or polyelectrolytes may provide for electrical and steric repulsion forces between suspended particles, if, upon adsorption on the particle surface, i) the adsorbed polymer chains render the particle surface electrically charged, ii) the adsorbed polymer chains occupy more than 50% of the particle surface area, and iii) the polymer segments dangle out off the particle surface into the surrounding dispersion medium, forming loops and tails. Once brought into play, these repulsion forces act to minimize interparticle associations, resulting in thinning of the suspension. The adsorption of cationic polyelectrolytes on the surface of clay platelets could potentially increase the attractive interaction between the clay platelets and the anionic debris particles, which in turn could enhance the flocculating ability of clay.
Although the prior art teaches the use of various types of anionic polymer as thinning agents for smectite clay suspensions, it does not disclose the effects of cationic polymers on the rheological properties (for example, viscosity properties) of concentrated clay suspensions (for example, suspensions having a smectite clay content exceeding 20% by weight). Therefore, it is not clear whether or not the addition of a cationic polymer to a concentrated suspension of smectite clay would produce either a "thin" or a highly shear-thinning suspension that shows a viscosity significantly lower than what it would have been in the absence of the polymer. It is only since the present invention that it has been found that cationic polymers with a weight average molecular weight falling within a certain range, when used even at relatively low concentrations, would render a concentrated suspension of smectite clays non-viscous, while the suspension shows considerable flocculating ability.
Although a targeted application for the product of the present invention is coagulation/flocculation of suspended matter in water streams as, for example, in wastewater treatment, because of the coagulating ability of the product, it may be used even as a drainage aid in the papermaking process, wherein the product helps in bringing about agglomeration of pulp fibers to facilitate the drainage process.
Other potential uses of the product include, but are not limited to, an additive in personal care and cosmetic formulations, as well as a fabric softener. The cationic polymer-modified clays would be substantive to (or adhere onto) the anionic surfaces of the hair or the skin, such that these clays can help deliver some useful hair care or skin care properties when used as an additive in personal care or cosmetic products. For example, the deposition of cationic clay platelets on the anionic surface of the hair shafts is expected to be substantive to hair shafts to enhance hair styling. Accordingly, the use of cationic polymer-modified clays in hair care products should add to the hair styling properties of these products. The prior art discloses the use of smectite clays as a fabric softener. Furthermore, the most commonly used fabric softeners are cationic surfactants. As for the molecular structure, surfactant molecules contain a hydrophilic part and a hydrophobic part, with the two parts of the molecule segregated from one another. The cationic surfactants used as fabric softeners impart softness by adsorbing onto the (negatively charged) fabrics with their hydrophilic part, consisting of the cationic functional group, attached onto the fabric surface, while their hydrophobic part projects outwardly from the surface. Such adsorption of the cationic surfactants minimizes interfacial tension between the fabric surface and the surrounding air mass and minimizes the adhesion of water to the fabric surface. This reduces the shrinkage (reduction of substrate surface area) and resulting hard "feel" that accompanies the removal of water from the substrate. In accordance with the present invention, the cationic modification of the smectite clay surface by the surface treatment of the clay with one or more cationic species, e.g., polymers, that contain one or more hydrophobic groups, render the clay platelets better equipped to serve as a fabric softener.

Nonviscous aqueous dispersion compositions of water-swellable layered silicates and the method of producing the same


Disclosed is a method for storing data of a log-structured file system (LFS), which does not separately store segment summary information (SS) and segment usage information (SU) but makes a checkpoint be included in a checkpoint record and written upon writing the checkpoint to improve write performance for a flash memory by decreasing the number of metadata to be written in a flash page.

Since a flash memory is inexpensive, and is low in power consumption and has a small size, the flash memory is widely used as a storage device in various embedded systems.
In particular, a NAND flash memory which is one of types of the widely used flash memories is constituted by a plurality of erase blocks and each erase block is constituted by a plurality of pages. In the case of a large block NAND flash memory which has been increasingly used in recent years, the size of one page is 2 KB and 64 pages are gathered to constitute one erase block.
The flash memory is capable of performing three operations of Read, Write, and Erase. Read/Write is performed by the page and Write is called a program. In order to program a page which has been programmed once again, the entirety of an erase block to which the page belongs needs to be first erased and the Erase operation requires more time than Read/Write operations. Since each erase block is limited in the number of erasable times, when the number of erase times reaches a limit, the corresponding erase block cannot be used. An erase block which cannot be used any longer corresponds to a bad block. Therefore, a sufficient life-span of the flash memory can be ensured only when wear leveling that enables the respective erase blocks to be evenly used is achieved.
As such, the flash memory has a problem in which it takes a long time to rewrite data in a region in which data has been written once again and a problem in which when the block of the flash memory is gradually abraded with repeated usage to reach a limit, the block cannot be used. Accordingly, a scheme is presented, which solves such problems by processing data by performing a specific operation in a file system corresponding to an upper layer of the flash memory.
A representative file system used in the flash memory is a log-structured file system. The log-structured file system stores data in a scheme that sequentially writes both metadata and data of a file system in a log by regarding a storage space as one log.
The log-structured file system includes a sprite LFS in which the log-structured file system (LFS) is implemented in a sprite operating system, a flash-friendly file system (F2FS) in which a structure of the sprite LFS is improved to be suitable for being used for a flash translation layer (FTL) based flash storage device, a new implementation of a log-structured file system (NILFS2) that provides a snapshot function, and the like.

Method for storing metadata of log-structured file system for flash memory

ELECTRONICS AND TELECOMMUNICATIONS RESEARCH INSTITUTE


Methods for treating spent reactive soap lubricant baths employed in a cold forming process for metal treatment are described. One method involves treatment of the spent solution with acid to form stearic acid, collection of the stearic acid, and reaction of the stearic acid with a metal salt to form metal stearates. This method is preferably used to prepare sodium stearate. An alternative method involves treatment of a basic (i.e., pH greater than 7 or preferably greater than 10) spent reactive soap lubricant bath with certain metallic stearates, including aluminum stearate, zinc stearate, aluminum stearate, zinc stearate, barium stearate, lithium stearate, and calcium stearate. The metal stearates can be used in conventional lubricant formulations used in the metal forming or metal working industry. Sodium stearate recovered by the present invention is of sufficient purity that it can be reused in reactive soap lubricant baths. In one preferred embodiment, the process of this invention is incorporated into a cold forming operation, thereby providing for an essentially closed process relative to the sodium stearate component.

Reactive sodium stearate lubricant systems are used extensively in the metal forming and metal working industry, especially in cold forming operations. Such reactive sodium stearate lubricant systems consist of high-purity sodium stearate in an aqueous solution and are often referred to simply as "reactive soaps." Such reactive soaps have been used in metal treating operations for at least the last forty years.
The reactive soaps for cold forming operations are prepared from high purity stearic acid which contains about 95 percent by weight, at a minimum, of the C-18 fatty acid and only low levels of heavy metals (i.e., generally less than about 0.01 percent by weight). Lower grades of stearic acid (often referred to as "rubber grade" stearic acid) contain less than about 70 to 80 weight percent of the C-18 chain length fatty acid. Such lower grades of stearic acid cannot be used to prepare reactive soaps. The high-purity grades of stearic acid necessary for reactive soaps are, of course, considerable more expensive than the "rubber grades." For example, stearic acid suitable for use in preparing reactive soaps currently cost about $0.55 per pound as compared to about $0.29 per pound for "rubber grade" material. Generally, a reactive soap bath contains about one pound of sodium stearate per gallon of bath. Based on the extensive use of such baths in cold forming of steel and aluminum, the cost of high purity sodium stearate represents a significant cost element in cold forming operations.
The metal work piece in cold forming operations is first phosphated in a zinc phosphate conversion bath whereby a zinc phosphate layer or coating is formed on the substrate or work piece. The phosphated work piece is then immersed in a high-purity sodium stearate or reactive soap solution (usually buffered at a pH of about 8 to 10). A reaction occurs between the sodium stearate and the zinc phosphate coating whereby a portion of the zinc phosphate coating is converted to zinc stearate via the following reaction: EQU Zn(PO.sub.4).sub.2 +6Na(OOC(CH.sub.2).sub.n CH.sub.3).fwdarw.3Zn(OOC(CH.sub.2).sub.n CH.sub.3).sub.2 +2Na.sub.3 PO.sub.4,
where n is 16. The lubricant system formed on the metal substrate consists essentially of three layers (in order): (1) a layer of zinc phosphate adjacent to the substrate surface; (2) a layer of zinc stearate formed by the above reaction on top of the zinc phosphate layer; and (3) a final or top layer of sodium stearate. In this system, the zinc phosphate is chemically bonded to the substrate surface and the zinc stearate is chemically bonded to the zinc phosphate layer.
One of the major drawbacks to the reactive lubricant system is its sensitivity to contamination by metals entering the bath during normal operation. The degree of conversion of the zinc phosphate to zinc stearate generally decreases with the age of the reactive soap bath. The decreased efficiency of a reactive soap bath is generally due to an increase in contaminants which interfere with or inhibit the reaction between the zinc phosphate and the sodium stearate. Such contaminants include heavy metals (e.g., zinc and iron) which may be introduced through "drag-in" from earlier stages of the treatment process and from reactions with the substrate, as well as calcium and magnesium salts from the aqueous media. Such metal contaminants form their corresponding stearates in the bath. Generally, when the combined metal contaminant levels in the reactive soap exceed about 0.1 percent by weight, the lubricant system is no longer satisfactory for most cold forming operations and is considered "spent."
The most common method of treating a spent reactive sodium stearate bath is to simply discard the bath and prepare a new bath using fresh, high-purity sodium stearate. Normally, the spent reactive soaps are hauled away by a waste disposal company for treatment and disposal. Such a system is economically and environmentally unsound. As environmental regulations on the disposal of such wastes increase, these costs are expected to increase. Most conventional methods for removing the metal contaminants from spent reactive soap solutions cannot be used. For example, any filtering media or system would be quickly clogged with fatty acids or soaps if such filtering methods were attempted. To date the only alternative to direct disposal of the spent reactive soaps is the mechanical removal of the metal contaminants by periodic or continuous centrifuging operations. Such centrifugation methods are messy, difficult, and costly and have not, therefore, been widely accepted. Although the metal working and metal forming industry has been aware of these problems and has been forced to deal with these problems on a daily basis for almost forty years, no generally satisfactory solution has been found.
It is desirable, therefore, to provide a method by which spent reactive soap lubricants can be easily treated. It is also desirable to provide a method by which high purity stearic acid can be recovered from spent reactive sodium stearate lubricant baths. It is also desirable to provide a method by which the useful lifetime of reactive sodium stearate solutions can be extended. The present invention achieves these and other objectives as fully described in this specification using a straight-forward and simple treatment process.


For a purpose of preventing a compressor from being damaged by liquid compression without disposing any accumulator on a low-pressure side, there is disclosed a transition critical refrigerant cycle apparatus having a supercritical pressure on a high-pressure side. The transition critical refrigerant cycle apparatus constituted by connecting a compressor, a gas cooler, a pressure reducing device, an evaporator and the like in an annular shape, using carbon dioxide as a refrigerant, and capable of having the supercritical pressure on the high-pressure side comprises: an internal heat exchanger for exchanging heat between a refrigerant which has flown out of the gas cooler and a refrigerant which has flown out of the evaporator. This internal heat exchanger comprises a high-pressure-side channel through which the refrigerant from the gas cooler flows, and a low-pressure-side channel which is disposed in a heat exchanging manner with this high-pressure-side channel and through which the refrigerant from the evaporator flows, the refrigerant is passed upwards from below in the high-pressure-side channel, and the refrigerant is passed downwards from above in the low-pressure-side channel.

1. Field of the Invention
The present invention relates to a refrigerant cycle apparatus constituted by connecting a compressor, a gas cooler, a pressure reducing device, an evaporator and the like in an annular shape, using carbon dioxide as a refrigerant, and capable of having a supercritical pressure on a high-pressure side.
2. Description of the Related Art
In this type of refrigerant cycle apparatus, a rotary compressor, a gas cooler, a pressure reducing device (expansion valve, capillary tube, etc.), an evaporator and the like have heretofore been successively piped/connected in an annular shape to constitute a refrigerant cycle (refrigerant circuit). Moreover, a refrigerant gas is sucked on the side of a low-pressure chamber of a cylinder from a suction port of a rotary compression element of a rotary compression, compressed by operations of a roller and a vane to constitute a high-temperature/pressure refrigerant gas, and discharged to the gas cooler from a high-pressure chamber side via a discharge port and a discharge-noise silencing chamber. After the refrigerant gas radiates heat in this gas cooler, the gas is throttled by throttle means, and supplied to the evaporator. There, the refrigerant evaporates, and absorbs heat from surroundings at this time to thereby exert a cooling function.
Here, in recent years, to handle global environmental problems, apparatuses have been developed in which carbon dioxide (CO2) that is a natural refrigerant is used without using conventional chlorofluorocarbon even in this type of refrigerant cycle and in which a transition critical refrigerant cycle is used for operation at a supercritical pressure on a high-pressure side.
In this transition critical refrigerant cycle apparatus, to prevent a liquid refrigerant from being returned into the compressor and compressed, an accumulator has been disposed on a low-pressure side between an outlet side of the evaporator and a suction side of the compressor in such a manner as to accumulate the liquid refrigerant in this accumulator, and suck a gas only into the compressor. Moreover, the pressure reducing device has been adjusted in such a manner that the liquid refrigerant in the accumulator does not return to the compressor (see, e.g., Japanese Patent Publication No. 7-18602).
However, when the accumulator is disposed on the low-pressure side of the refrigerant cycle, more refrigerant charge amount is required. To prevent liquid backflow, a capacity of the accumulator has to be increased, and throttle of the pressure reducing device has to be adjusted. This has resulted in enlargement of an installation space or drop of refrigeration capability in an evaporator 15.
Moreover, since a compression ratio is very high in a case where carbon dioxide is used as the refrigerant of the refrigerant cycle apparatus, it has been difficult to derive a refrigeration capability at high temperature of outside air or the like.