A method and device for interpolating a pixel of an interline of a first field in a sequence of interlaced fields includes selecting at least one first pixel and one second pixel from scan lines of the first field adjacent the interline, and a third pixel from a second field temporally preceding or following the first field. The image position of the third pixel corresponds to the image position of the pixel to be interpolated. Also selected are fourth and fifth pixels which lie vertically adjacent the third pixel in the second field. A first filter value is generated by low-pass filtering the at least one first and second image information values. A second filter value is generated by high-pass filtering the third, fourth and fifth image information values. An image information value of the interpolated pixel is generated using the first and second filter values.

The invention relates to the field of video signal processing, and in particular to the field of interpolating a pixel of an interline of a first field from a sequence of interlaced fields.
Television signals normally contain information for temporally successive fields which can be displayed on the screen, where two successive fields are interlaced (i.e., have different raster positions). Each field contains image information only in every other scan line, where a scan line for which image information is present in the one field is always empty in the second field. In the following discussion, image information values are understood to mean, specifically, brightness values (luminance values) or color values (chrominance values).
FIG. 1 illustrates two such successive fields A and B, where the first field A has scan lines A1, A2, A3, A4 and A5 for which a received video signal contains image information. The field B includes scan lines B1, B2, B3, B4 and B5 for which a received video signal contains image information. The raster positions of the fields A and B are mutually offset in such a way that the positions of the scan lines of the field B correspond to the positions of the empty interlines of the field A, and vice versa.
In order to enhance image quality, it is often desirable to generate complete frames, i.e., images in which no empty interlines are present.
In one particularly simple method, the approach is to double each of the fields, that is, simply to output the content of a superior or inferior scan line as an interline of a field. In this method, continuous brightness or color transitions in the resulting image have a stepped appearance. In addition, edges running diagonally through the image appear stepped or stair-like.
Another known approach to interpolating a pixel in an interline of a field is to utilize the image information values for pixels that lie vertically adjacent to the pixel to be interpolated, and to implement a linear averaging of these image information values. However, in this method, edges running horizontally through the image are not reproduced sharply.
In addition to the pixels of the field which surrounds the pixel to be interpolated, it is also possible to employ the image information values of temporally preceding or following fields for purposes of interpolation.
European Patent EP 0192292 B1 proposes an approach for interpolating a pixel of an interline from a field in which two pixels are selected from the field in which the pixel to be interpolated is located. That is, one pixel from a scan line above the interpolation pixel and one pixel from a scan line below an interpolation pixel, where the horizontal positions of the selected pixels correspond to the horizontal position of the interpolation pixel. In addition, a pixel of a scan line is selected from a temporally following field, where the position of this pixel corresponds to the pixel position of the interpolation pixel. In this known method, the average value of the image information values for these three pixels is determined, and image information of that pixel is selected for which the image information most closely approximates the average value determined. The pixel of the second field is, in other words, utilized for interpolation if the image information of this pixel lies between the image information values for the pixels of the field with the intermediate spot to be interpolated. Otherwise, the image information of one of the pixels from lines adjacent to the interpolation pixel is selected—with the result that one of these values is doubled, i.e., reproduced twice one below the other. However, this mere repetition of a pixel results in a positionally incorrect display of highly vertical transitions, a phenomenon which is particularly noticeable in edges running diagonally in the image.
The publication Kovacevic J; Safranek, R. J.; Yeh, E. M.: Deinterlacing by Successive Approximation, IEEE Transactions on Image Processing, February 1997, pp. 339-344 discloses a method of interpolating a pixel from an interline in which the value of the interpolation pixel is determined utilizing weighting factors, from the pixels lying vertically above and below the interpolation pixel, and from an additional pixel which is selected from a preceding or following field.
U.S. Pat. No. 5,661,525 similarly describes a method of interpolating a pixel in which pixels directly vertically adjacent to the interpolation pixel as well as pixels from preceding or following fields are selected, wherein these selected pixels are weighted to generate the interpolation pixel.
European Patent application EP 0 227 190 describes a method of interpolating a pixel within a field, wherein pixels lying above and below the interpolation pixel are selected and compared. If the difference between these two values is greater than a predetermined value, the larger or the smaller pixel value is selected as the interpolated pixel value. If the difference is smaller than the reference value, one of the two adjacent pixel values, or the average of these pixel values, is selected as the interpolated value.
U.S. Pat. No. 5,910,820 describes a method of interpolating a pixel in which a weighting of selected pixels is implemented depending on a threshold value and depending on the difference between pixel values for the pixels adjacent to the interpolation pixel.
European Patent application EP 0 946 054 A1 describes a method of interpolating a pixel using a weighted 3-tap median filter. The pixels vertically adjacent to the interpolation pixel and the pixels of a temporally preceding or following field are fed to the median filter.
German Patent DE 689 27 957 T2 describes a method of sampling conversion of a television signal, wherein two data values of a first field and a data value of a second field are selected. An average value is generated from the data values of the first field, and a weighted average value is generated from all three data values. One of the three selected data values, the average value of the data values from the first field, or the weighted average value of all data values, is outputted as the interpolated value.
U.S. Pat. No. 5,475,438 describes a method of pixel interpolation in which the average of the pixel values of two pixels is generated which lie vertically adjacent to the interpolation pixel, and in which a pixel is selected from the field preceding the field with the interpolation pixel and from a field following the field with the interpolation pixel. The average value together with the pixel values from the preceding or following field are fed to a median filter, the output value of which is weighted and added to the similarly weighted average value.
There is a need for a system and method for interpolating a pixel of an interline of a field from a sequence of interlaced fields, which ensures a correct display of edges running horizontally through the image, suppression of stepping in diagonally running edges, and a correct reproduction of movements.

Method and device for interpolating a pixel of an interline of a field


A radio frequency automatic identification system detects targets which include solid resonators resonating at several frequencies, attributing information to the frequencies at which the target resonates. Preferred resonators are quartz crystals, which may be made by a process of heating quartz to soften it and cutting crystals to approximate size and resonant frequency. Resonators produced by such a process are measured to determine their actual resonant frequency, and preferably the crystals are sorted into predetermined frequency windows in accordance with their measured resonant frequency. A set of resonators having frequencies corresponding to predetermined data is selected from the sorted groups of resonators and incorporated into a target. The preferred target is an ink-like material having a plurality of resonators disposed in a matrix which is radio frequency transparent at the frequency of interest. Targets are preferably detected by repetitively sweeping the frequency of the interrogating signal through a range which includes the information-bearing range of the system.

Automatic identification systems are widely used to input data into computer systems and to control operation of equipment. Radio frequency operated systems are often used in automatic identification applications where identification of an object is to be made without contact and where the application may not permit line-of-sight communication between the object and a sensor. Radio frequency automatic identification ("RF/AID") systems are based on "targets" which generally function as transponders. Upon receipt of a radio frequency interrogating signal, the target responds by producing a detectable radio frequency response signal. Such targets have taken the form of tags or labels which are affixed to an object to be identified. As used herein, a "target" is any radio frequency responsive means which may be attached to, printed upon, or otherwise associated with an object to be identified.
Automatic identification systems are presently used or contemplated for use in a wide variety of applications for monitoring of people, animals, locations, and things. Such applications include material handling, such as automatic storage and retrieval; cargo handling, such as baggage sorting and tracking; asset management, such as of rental vehicles or for retail theft control; identification of persons, such as for facility access control or patient tracking; and identification of animals, such as for automatic feeding.
One major attribute of presently available RF/AID systems which limits their use is that the target cost is substantial. The cheapest currently available radio frequency responsive targets cost on the order of $10 per target, and many cost on the order of $100 per target. This high cost substantially restricts use of such systems to situations where the target can be reused, such as in retail theft prevention where targets are removed from an item after purchase and reused on other items. Another attribute which restricts use of present RF/AID systems is the target size. Targets are typically several inches long, which inhibits their use where small items are to be identified or where it is desired that the target be unobtrusive.
Both of these attributes result in large part from the structure typically employed for RF/AID targets and the frequency at which they operate. Such targets typically contain an antenna for receiving an interrogating RF signal; radio frequency processing means for determining whether an interrogating signal has been received; and radio frequency transmitting means responsive to the processing means for transmitting a detectable RF response signal from the target. Present systems typically operate at fairly low frequencies.
The present invention is directed to a new system for RF/AID which avoids the foregoing drawbacks.

Radio frequency automatic identification system


A circuit for varying an amplitude of an oscillation signal comprises an oscillator, signal processing circuitry, a first feedback circuit, and a second feedback circuit. The oscillator generates the oscillation signal and has a control input to vary the amplitude of the oscillation signal. The signal processing circuitry processes the oscillation signal. The first feedback circuit is configured to control the control input of the oscillator by comparing a reference value and an input amplitude of an input of the signal processing circuitry. The second feedback circuit generates the reference value by comparing an output amplitude of an output of the signal processing circuitry and a predetermined value.

1. Field of the Invention
This invention relates generally to oscillators and more specifically to oscillators with variable reference.
2. Description of the Background Art
For signal processing circuitry to operate linearly and optimally process an analog signal, the analog signal should be within a limited range of amplitude. For example, if an input signal to the signal processing circuitry is too low in amplitude, noise that is present in the signal processing circuitry represents a relatively large part of the input signal. The input signal that is too low in amplitude results in a poor signal-to-noise ("S/N") ratio in an output of the signal processing circuitry. Conversely, if the input signal to the signal processing circuitry is too high in amplitude, then the signal processing circuitry can operate nonlinearly, resulting in distortion or "clipping" in the output.
FIG. 1 illustrates circuitry including automatic gain control ("AGC") in the prior art. AGC 110 detects an output amplitude at an output 130 of the signal processing circuitry 100 to control the gain of a gain adjustment amplifier 120 in the signal processing circuitry 100. If the output amplitude at the output 130 is too low in amplitude, then the AGC 110 increases the gain of the gain adjustment amplifier 120. Conversely, if the output amplitude at the output 130 is too high in amplitude, then the AGC 110 decreases the gain of the gain adjustment amplifier 120.
One problem with the AGC approach of FIG. 1 is that extraneous components are required in the signal processing circuitry 100 to support the AGC function, but are not otherwise needed. For example, the gain adjustment amplifier 120 of FIG. 1 is necessary for AGC, but does not perform any signal processing function in the signal processing circuitry 100. Another problem is that extraneous components in the signal processing circuitry 100 contribute undesired noise and/or distortion in the output of the signal processing circuitry 100.
FIG. 2 illustrates a circuit 200 to control an amplitude of an oscillation signal in the prior art. The circuit 200 limits an amplitude of the oscillation signal at an input 210 of the signal processing circuitry 240 to within a predetermined range. An oscillator 222 generates the oscillation signal that a buffer 215 amplifies to create the input 210 of signal processing circuitry 240. A peak detector 230 compares the input amplitude at the input 210 of the signal processing circuitry 240 to a predetermined range 235 and generates a control signal 250 to control the amplitude of the oscillator 222. The amplitude of the oscillation signal is adjusted based upon a desired input amplitude at the input 210 of the signal processing circuitry 240.
The approach of FIG. 2 excites oscillation in the oscillator 222, minimizes phase noise or jitter in the oscillation signal at the input 210 or input 260, or reduces the power consumed by the oscillator 222. However, one problem with the circuitry 200 of FIG. 2 is that the amplitude of the oscillation signal generated by the oscillator 222 is based upon only a predetermined range of amplitude, and not upon the actual amplitude of signals at some node in the signal processing circuitry 240 or another component following or "downstream" of the oscillator 222 such as the comparator 270. For example, the amplitude of the signal at the input 260 to the comparator 270 may be too high for the comparator 270 to operate optimally if the signal processing circuitry 240 experiences an increase in its gain characteristics due to process variations, voltage fluctuations in a power supply (not shown) powering the signal processing circuitry 240, and/or a change in operating temperature of the signal processing circuitry 240.
Therefore, a need exists to address the aforementioned deficiencies and inadequacies.


An adapter on the nose of a pneumatic ram engages the end of an underground pipe and under the action of the ram drives the pipe ahead of it for removal. The adapter has a frusto-conical channel at the larger diameter end of a frusto-conical region of a nose section for receiving the end of a pipe upon radial expansion of the pipe end to thereby secure the adapter to the pipe while preventing excessive radial expansion of the pipe end.

The present invention relates to removing underground piping and more particularly to replacing deteriorating underground gas piping with new piping. The invention is of particular utility in removing deteriorating steel pipe lines used to provide gas service from the street mains into an adjacent building.
Heretofore, replacing local gas lines required excavating a trench from the building out to the main, a costly operation causing disruption of walkways and roadways. The lines require replacement as a consequence of deterioration through corrosion. The current practice is to replace the steel pipe sections with plastic piping.
Several companies produce pneumatic tools with various adapter heads for boring passages under pavements and the like to minimize the amount of trench excavating required. The known pneumatic tools are constructed to either drive a pipe before it or trail a pipe behind it as it bores a passage before it. These pneumatic tools are variously identified as "boring tools" or "piercing tools", and the like. They have also been called "missiles", "moles" and "rams". The term "pneumatic ram" will be used in the following disclosure to encompass all of such tools. As far as is known, such tools have never been adapted and used to drive an already installed pipe out from its embedment.


A radial vent composite heat pipe system for cooling and increasing the power density of an electrical machine is provided. The system comprises a plurality of radial vent composite heat pipe assemblies each comprising a slot portion thermally connected to a vent portion. The slot portions are disposable within respective stator slots of a stator core pack of a stator assembly of the electrical machine. The vent portions are disposable within stator vents of the stator assembly. The slot portions absorb heat from the stator coils of the stator assembly and transfer the absorbed heat to the vent portions. The vent portions reject the transferred heat into a cooling air flowing through the respective stator vent, thereby rapidly transferring heat from the respective stator coil to the cooling air flowing through stator vent, and thereby greatly increasing the power density of the electrical machine.

The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Typically, large motors, generators and transformers (i.e. large electric machines) remove internal heat in the following fashion. Air is ingested at one or both ends of the rotor. The air can be ingested solely by the suction created by the pumping action of the rotor or assisted by external blowers. Part of the ingested cooling air blows directly over the stator coil end turns. It should be noted that some electric machines have the air that has passed through the rotor and stator and is slightly heated blow over the exposed coil end turns before exiting (as is the case with single end ventilated machines).
The ingested air travels axially down the rotor in the space between the shaft spider bars and is pumped through the rotor radial vents by the rotor bars. The air is then pumped through the air gap (the radial space between the stator and the rotor) and into the stator radial air vents. The air enters the stator radial air vent and blows over the exposed coil end head (i.e. the coil section in the vent section and not the core section where the coil is surrounded by the stator core iron). The air then blows through the rest of the radial vent until it is exhausted at the outside diameter of the stator core. The radial vent sections alternate with the core pack sections. A typical core section is 1.75″ long and a typical radial vent sections is 0.5″ wide. However, the sizes and proportions of the core packs and air vent sections vary significantly from one design to the next. In addition, some designs have the stator and rotor vent packs aligned with each other, while in other designs they are offset.
The above description does not include the airflow through the frame, bearing brackets, air enclosures, etc., as these details are machine specific and commonly known to one skilled in the art.
The power density of such electric machines is thermally limited by the stator coil temperature. In particular, the stator coil temperature is limited by the maximum allowable temperature of the electrical insulation system (i.e. the insulation that surrounds the coil). It should also be noted that approximately 50% of the total motor losses (which manifest themselves as heat) are generated within the stator coils. The heat that is generated within the coil has three parallel paths by which it can be shed: 1) convection in the small section of exposed coil (i.e. the part of the coil that is in the vent packet area) directly cooled by the air flow; 2) conduction in the larger section of stator coil that is surrounded by the stator core iron (i.e. the part of the coil that is in the core packet section). This area is cooled by conducting heat from the coil to the core iron, and the again by conduction as the heat travels axially in the core pack section until it gets to the outermost lamination in the core pack area. This outermost stator iron lamination has the heat is removed via convection by the cooling air as it travels in the radial air vent; and 3) convection in the exposed coil end turns directly cooled by the air flow.
The stator coil temperature is a balance of how much heat is generated in the coil and how effectively this heat is rejected through the three parallel paths as described above. This maximum coil temperature limits the maximum power that a particular machine can produce.
As described above, approximately half of the heat is generated in the coil. A large proportion of the coil is surrounded by the core iron, and thus not effectively cooled. For instance, if the air vent is 0.5″ wide and the stator core pack length is 1.75″, then only 22% of the coil length is directly exposed to the cooling air. The thermal resistance is very high between the coil in the core pack area and the face of the radial vent (this is also the outermost lamination of the core pack) where it is convected to the air stream. This high thermal resistance path is the only heat transfer path for the larger stator coil area where most of the heat generated in the coil is generated. Details for this long, torturous heat transfer path resulting in the high thermal resistance is as follows.
Within a specific core pack section, heat is conducted through the center portion of the stator coil to the outer edges of the coil. This heat is then conducted from the outer surface of the stator coil through the electrical insulation. The coil insulation has a high thermal resistance, but it is very thin (typically 0.030″ per side for medium voltage (4000 Volt) electric machine, but the actual thickness varies significantly from one design to the next). The heat is then conducted from the insulation to the stator slot edges in the stator core. The edges are formed from the individual laminations. All the laminations in the core pack are make up a core pack area.
Heat is conducted radially and axially in the stator core from the slot area to the surface of the radial air vent. The stator core is not a solid block of steel, but consists of many very thin steel plates (i.e. the stator laminations). These laminations have insulation on the surfaces which further raises the thermal resistance and inhibits heat transfer in the axial direction.
Typical stator laminations are 0.018″ thick. Lamination thickness varies significantly from design to the next. This example of an electrical machine with a 1.75″ core packet length would consist of 95 individual laminations. The net impact of high thermal resistance is that it takes a greater temperature differential to move a given amount of heat. Conversely, the amount of heat that is transferred is limited by the temperature rise between the where the heat is generated (the stator coil) and where it is rejected (the air flowing through the radial air vent). Electrical machines are designed to balance the amount of heat that can be removed while staying below the maximum temperature limit at the coil. Very often, temperature sensing devices (such as resistance temperature devices (RTDs)) are placed directly in the stator slot to measure the temperature in the coil at the slot to assure that the maximum temperature limit is not exceeded. The stator coil is shown in FIG. 4.
Finally, the heat is convected to the air flowing through the radial air vents. There are two paths where the flowing air absorbs the heat: the air flowing directly over the short exposed section of stator coil and the air which is flowing through the rest of the air vent absorbing the heat that has been conducted through the stator core.


A local area network including at least one hub unit, at least one associated station unit and a wireless communication link between each hub unit and its associated station units. The communication link includes a wireless down-link channel for transferring information from each hub unit to its associated station units and a wireless up-link channel for transferring information from each station unit to its associated hub unit. Communication is conducted in accordance with a combination time division multiplexing and contention based protocol. A synchronized common slotted time frame between each hub unit and its associated station units is imposed by the hub unit.

This invention relates to multiple access communication systems. More particularly, it relates to multiple access wireless local area network (LAN) communication systems.
The need for wireless interconnection of computers operating over LANs has become increasingly apparent as the popularity of LAN usage in office environments has grown. Traditionally, computers and computer related devices operating as part of a LAN have been interconnected using such conventional technologies as twisted pair, coaxial cable and optical fiber cable. A primary goal of conventional systems has been to utilize these technologies to realize fast, reliable, multiple access communications over the LAN. Historically, several communication protocols and topological architectures have been combined with traditional interconnection technologies to realize this goal.
In attempting to achieve the goal of fast communication, the issue of how to make efficient usage of the chosen transmission medium was repetitively addressed by prior art systems. A common trade off encountered with respect to bus allocation is how to allocate bus usage between high duty cycle subscribers and low duty cycle subscribers whose transmissions are characterized by a high peak-to-average transmission rate. Such low duty cycle subscribers are commonly referred to as "bursty" subscribers. Three general approaches were developed; time division multiplexing, frequency division multiplexing and space division multiplexing.
Time Division Multiplexing (TDM) attempts to take advantage of transmission mediums which can support a faster communication data rates then are required by any one user on the network. Essentially, multiple digital communication signals are interleaved in time over a single transmission path. Many different types of TDM based systems have become well known in the art. Examples include polling, priority request, communication path contention, and cyclic time division systems.
In a polling system, a central controller polls remote stations, offering each an opportunity to utilize the communication path. In a priority request system, remote stations request usage of the communication path and a central controller awards control of the path according to priority levels assigned to each station. Contention systems generally involve remote stations transmitting at random times and then retransmitting in the event of a detected collision. In a cyclic time division implementation, devices on the network are only permitted to transmit during a preassigned periodically occurring time slot. Some cyclic time division systems have fixed slot lengths and a fixed period while others allow for these parameters to be dynamically updated. Still others control the length of the time slots by passing a digital code, called a token, between devices operating on the network. Only when a device possesses the token, may it transmit.
Frequency Division Multiplexing (FDM), attempts to exploit transmission mediums which can support a wider bandwidth than is necessary to accommodate the highest frequency baseband device coupled to the network. In an FDM system, each transmission signal is modulated onto a different carrier signal operating about a particular center frequency. Each unique carrier signal is referred to as a channel. One example of frequency division multiplexing is frequency shift keying (FSK). FSK systems may be designed to operate in either a full or half duplex environment. A full duplex implementation assigns separate channels for transmission and reception, thereby enabling transmission and reception to occur simultaneously. Alternatively, half duplex systems require a single channel to be time multiplexed for both transmission and reception. FSK systems generally represent a logical one by a frequency shift in a particular direction relative to the center frequency. Similarly, a logical zero may be represented by an equivalent frequency shift in the opposite direction.
Space Division Multiplexing (SDM) simply adds more signal paths which are spacially isolated from each other, thereby increasing the number of signals that can be simultaneously transmitted. As implemented in a local area network, this involves providing a separated interconnection between any two devices wishing to communicate.
Another common issue raised in attempting to efficiently utilize a transmission medium is whether to implement a baseband or a broadband system. In the context of LANs, broadband refers to any system which transmits the digital information as an analog signal. One example is the FSK approach discussed above. Another example is phase shift keying (PSK). As the name suggests, PSK entails representing a logical one by a signal having a particular frequency and a particular phase while representing a logical zero by a signal having identical frequency but being phase shifted by a predefined amount.
The transmission path multiplexing approaches discussed above have traditionally been applied to various permutations of four topological architectures. These topologies are commonly referred to as; bus networks, loop networks, ring networks and star networks.
A bus network is one of the simplest configurations. In this type of a system the network is typically comprised of a passive transmission bus. The bus may consist of a single cable or many branches. Devices operating on such a network, commonly referred to as subscriber devices, interface directly to the bus and every device has access to transmissions from every other device. Since the bus is passive, it is the responsibility of the devices operating over the network to manage bus access. Traditionally, both frequency and time division multiplexing have been employed on such systems.
A loop network typically consists of an inbound unidirectional signal path, an outbound unidirectional signal path and a unidirectional path coupler for transferring signals from the inbound path to the outbound path at the system head-end. A loop network may also be a passive system. However, in some prior art implementations, a digital bus repeater (DBR) is employed as a path coupler. A DBR provides certain minimal formating functions and regenerates signals tending to deteriorate over long signal paths. Devices operating on a loop network typically interface to the network via an appropriate bus interface unit (BIU). As in the case of bus networks, both frequency and time division multiplexing have been utilized for efficient transmission path allocation.
A ring architecture, in its most rudimentary form, is a unidirectional closed loop signal path. Typically, devices may interface to the ring either directly or through an appropriate BIU. In some prior art implementations DBRs are inserted into the signal path periodically around the ring, and each subscriber device interfaces to the ring via a DBR. In other prior art implementation, two concentric unidirectional rings are employed. In an analogous fashion to the loop network, one ring services incoming communications signals while the other services the outgoing. Since the ring is a predominantly passive network, the devices operating over the network are responsible for efficient network allocation.
A star network typically involves having each subscriber device connected, via a dedicated communications path, to a central communication controller. Traditionally, if one device on the network wishes to send a message to another device on the network, it transmits the message to the central controller and the central controller, in turn, redirects the transmission to the appropriate destination device. In other prior art implementations of star networks the central controller acts as a switching unit. As such, instead of relaying communications, upon request from a transmitting device, it Performs switching operations to physically connect a transmitting device to a specified receiving device. As can be seen, the central controller relieves the subscriber devices of responsibility for efficient network allocation.
Many common prior art implementations have been developed which employ contention type time multiplexing protocols in an attempt to realize the most advantageous usage of the above discussed topologies. One early implementation, capable of utilizing either a bus, loop or ring topology can be characterized as a free-for-all system. According to this early implementation, subscriber devices transmitted at random and then waited a period of time for an acknowledgment from the destination device. If no acknowledgment was received then the sending device retransmitted. A substantial deficiency of this system was the number of communication collisions caused by contending subscriber devices.
Subsequent prior art implementations improved on this approach by adding a carrier sensing feature. Generally referred to as carrier sense multiple access (CSMA) or listen before talk (LBT), this protocol required transmitting devices to determine whether the shared communication path was available prior to beginning a transmission. However, this protocol, nevertheless, suffered inefficiencies because collisions of simultaneously transmitted signals went undetected until the transmitting device failed to receive the expected acknowledgment from the receiving device.
The CSMA approach was later improved upon by the addition of collision detection (CSMA/CD), also known as a listen while talk protocol (LWT). According to a LWT protocol, the transmitting device monitors the bus during transmission so that a collision is detected at the earliest possible time. Considerable time savings occur by early detection if transmission distances are such that there is a long round trip delay between the transmitter and the receiver. Additional time savings occur when lengthy communications are involved and a collision occurs early on in the transmission.
Several non-contention based prior art systems have been developed which relieve subscriber devices operating on the network from having to detect collisions. One such implementation which tends to eliminate communication collisions is a cyclic TDM approach, commonly referred to as a token passing ring. As the name suggests, this network exploits a ring type architecture. In a token passing ring system, the devices on the network continuously pass, between themselves, a digital code, called a token. Only when a device possesses the token, may it transmit data over the ring. In this way network communications are interleaved in time. FDM may also be utilized to modulate the baseband signals being time multiplexed over the communication path.
Two other implementations of cyclic TDM systems are well known in the art. They are fixed slot allocation and dynamic slot allocation. In a fixed slot allocation system, regularly occurring time slots in a repetitive framed sequence are dedicated to specific devices operating on the network, for their transmissions. In dynamically allocated systems, Parameters such as the size of each time slot and the number of time slots allocated to a particular device may be varied. Since a device only transmits during its allocated time slots, communication collisions generally do not occur.
Although the above discussed prior art implementations have succeeded in realizing fast, reliable, secure communications in a multiple access LAN environment, they nevertheless suffer from substantial deficiencies. High on the list of drawbacks to a hardwired system is the considerable cost of installation resulting from having to run cables throughout an office. Another deficiency is the difficulty associated with relocating subscriber devices within an office. A further drawback of hardwired systems is the cost and difficulty associated with moving an entire system from one location to another. Therefore, the most recent activity in the field of LANs has centered around the development of wireless LANs.
There are two primary technologies being developed to provide wireless LAN connections. One is infrared light and the other is radio. Most systems that propose the use of light to transmit data over a local area networks focus on wavelengths in the infrared part of the visible spectrum. This choice is natural because the physical devices for transmitting are plentiful and inexpensive. Additionally, infrared technology is also suited to very high data rates.
However, infrared communication systems are mostly limited to line-of-sight links because light cannot penetrate doors and walls. Systems which use diffused sources and which rely on reflections off walls and ceilings have been built, but none have succeeded in multiple-room environments without the use of extensive repeater networks. Additionally, infrared tranceivers are easily interrupted by people walking around an office.
Radio waves have long been used for voice communication. Hand-held walkie-talkies are essential for plant-maintenance personnel in large office buildings. FAX and telephone communications over cellular radio links are becoming integral to many modern businesses. The use of radio technology for high speed data communication over such links is now emerging.
The primary advantage that radio has over infrared is its ability to penetrate most solid objects found within a building. Consequently, objects such as wall boards, wood doors, modular office walls, and people will not disrupt a radio signal to the same degree as an infrared signal. However, prior art systems have yet to completely overcome several difficulties inherent to designing a radio based LANs for operation in an office environment.
One significant difficulty is effectively dealing with multiple signal paths created by transmission signal reflection. Other issues involve guarding against unauthorized reception of communication signals and interference with those signals.
The FCC has recognized the need to use radio transmissions for commercial in-building communication systems and has allocated three separate bands for low powered systems that do not require user licensing. Specifically, these frequency bands are 902-928 MHz, 2.4-2.5 GHz, and 5.8-5.9 GHz. The 902-928 MHz band is both fairly narrow and crowded with such devices as store security systems and paging systems. However, the other two bands offer sufficient bandwidth to transmit data at LAN megabit data rates and they are virtually free of interference from other devices.
Another frequency band that is being used for wireless networks is 18-19 GHz. This frequency range does offer a great deal of bandwidth, ten 10 MHz channels. However, the use of this band requires an FCC license on a per location basis. This restricts the freedom a user has in installing a wireless LAN as well as the ability to move the system. Connection costs are significantly higher because the cost of radio components increases along with the frequency.
Another drawback to utilizing this band is that it is very close to infrared and as a result, shares many of the propagation characteristics of light. Since signal penetration of solid objects, such as walls is low, the effective range is small, typically a 40 foot radius. This increases the need to provide many repeaters to cover a typical office environment and further increases the overall system cost.
Accordingly, it is an object of the present invention to provide a wireless, radio frequency, multiple access communication system for use within an office environment.
It is a further object to provide a wireless, radio frequency, multiple access communication system which is effectively immune to information transmission problems caused by signal reflections.
It is another object of the invention to provide a wireless radio frequency, multiple access communication system which accommodates both high and low duty cycle subscribers.
An additional object of the invention is to provide a wireless radio frequency, multiple access communication system which implements a carrier sense multiple access with collision detection protocol.
Another object of the invention is to provide a wireless system which avoids any need for FCC licensing, thereby providing the user with additional flexibility with respect to system installations and subsequent system relocation.

Wireless local area network communications system


An overhead sensing device for motor vehicles and the like comprises a non-conductive flexible feeler adapted for contacting an overhead obstruction, and an actuation device for outputting a signal in response to the non-conductive flexible feeler contacting an overhead obstruction. An audible and a visual signal device signals the operator in the case where the non-conductive flexible feeler contacts an overhead obstruction. The audible and visual signaling device are operative in response to the output of the actuation device. A control device, including a remote control device, controls the height of the non-conductive flexible feeler above a highest point of the motor vehicle.

1. Field Of The Invention
The present invention relates to an overhead obstruction sensing device for motor vehicles and the like which provides an audible and/or visual alarm in the case of contact with an overhead obstruction.
2. Description Of The Related Art
Motor vehicles and, in particular, semitrailer trucks are constantly troubled with insufficient overhead clearance when passing under overhead obstructions such as bridges, loading docks, tree branches, and overhead wires In view of the danger and monetary damages associated with motor vehicles coming into contact with overhead obstructions, sensing devices have been developed for warning of potential contact with an overhead obstruction.
For example, U.S. Pat. No. 4,307,375 describes a sensing device which includes a vertically adjustable metal shaft mounted on a motor vehicle forward of the highest point on the motor vehicle. The metal shaft is connected to a microswitch device which is actuated upon deflection of the metal shaft by contact with an overhead obstruction. The height of the metal shaft is adjusted to match the height of the motor vehicle. The micro-switch device, if actuated, allows current to flow to an alarm thereby warning the operator that the overhead clearance is insufficient.
Conventional sensing devices, however, are difficult to adjust vertically, and it has heretofore been difficult to match the height of the motor vehicle to the height of the metal shaft. In addition, because such sensing devices operate by contacting overhead obstructions, there is danger if the overhead obstruction is a high-tension power line or the like.


A sensor head is configured by beam-welding a magnetostrictive sleeve made of a magnetostrictive material to an intermediate sleeve. The intermediate sleeve is longer than the magnetostrictive sleeve. The intermediate sleeve protrudes from both ends of the magnetostrictive sleeve by a length "L". For the sensor head, an annealing process is performed. The sensor head for which the annealing process is performed is installed to a shaft. At this time, the contact portion between both ends of the intermediate material and the shaft are beam-welded all around.

1. Field of the Invention
The present invention relates to a torque sensor, and more particularly to a method for installing a magnetostrictive torque sensor in a measurement target.
2. Description of the Related Art
Torque measurement is performed for various use purposes in a variety of industrial fields. For example, in an automobile field, torque measurement is being put into practical use in order to detect the torque caused to occur by a driver's operation using a steering wheel in an electromotive power steering system, or to detect the torque in the rotational direction of tires when running. Provided below is the explanation about the example where the torque which is used in an automobile field and delivered to a shaft, is detected.
As a method for detecting torque, a magnetostrictive torque sensor using a magnetostrictive material is known. The magnetostrictive material has the nature that its magnetic characteristic changes as its shape is distorted. It is fixed to a target whose torque is to be measured (a shaft in this case). If torque is applied to the shaft, the shape of the magnetostrictive material fixed to the shaft is distorted. As a result, the magnetic characteristic of the magnetostrictive material changes. Therefore, the torque applied to the shaft can be detected without contact (indirectly) by detecting the magnetic characteristic of the magnetostrictive material.
As a method for fixing a magnetostrictive material to a shaft, the method for directly attaching the magnetostrictive material to the shaft and fixing it, and the method for interposing a sleeve (a support sleeve 104) between the magnetostrictive material and the shaft and fixing the magnetostrictive material as disclosed by the patent gazette TOKKAIHEI 1-97823, are known. A drawing used in the patent gazette TOKKAIHEI 1-97823 is shown in FIG. 1.
With the former method, the magnetostrictive material is fixed to the shaft by being welded or soldered, or by using an adhesive. With the method disclosed by the patent gazette TOKKAIHEI 1-97823, a measurement sleeve 101 made of a magnetostrictive material is soldered to the support sleeve 104. The support sleeve 104 is fixed by being welded using induction heating or by being solder to a shaft 105 to be measured. Note that the patent gazette TOKKAIHEI 1-97823 is a patent application, one of whose features is that the support sleeve 104 is arranged in order to reduce residual stress caused in the method of fixing a magnetostrictive material directly to a shaft.
The configuration disclosed by the patent gazette TOKKAIHEI 1-97823 aims at solving the problems of the conventional configurations as described above. However, totally judging from the sensitivity as a magnetostrictive sensor, residual stress, the degree of convenience of installation to a shaft, a bad influence of heat on the shaft, etc., there are points that must be further improved.
According to the patent gazette TOKKAIHEI 1-97823, a measurement sleeve 101 made of a magnetostrictive material is soldered and fixed to the support sleeve 104 in the state where slits are formed in measurement areas 102 and 103. With such a process, however, the magnetostrictive material is damaged by heat which is not necessary for metal composition, and the desired magnetic characteristic may not be obtained. Furthermore, residual stress is considered to occur due to a difference between the thermal expansion coefficient of the magnetostrictive material, the support sleeve and that of the solder material, although it is not large. If the magnetostrictive material is damaged by heat, the sensitivity as a magnetostrictive sensor is degraded. Additionally, if the residual stress occurs in the magnetostrictive material, it becomes difficult to correctly detect the torque delivered to the shaft. The support sleeve 104 and a shaft 105 to be measured are fixed by being welded using induction heating or by being soldered, so that the temperatures of the support sleeve 104 and the shaft 105 to be measured become high in a wide range with these methods. As a result, the residual stress is caused to occur in the magnetostrictive material when the support sleeve 104 to which the measurement sleeve 101 is installed is fixed to the shaft 105 to be measured. Additionally, since the shaft 105 to be measured, to which the torque is delivered, is tempered, its strength may deteriorate.
For welding using the induction heating, it is desirable to reduce the contact area between two objects which are to be welded. Accordingly, in the example referred to in the patent gazette TOKKAIHEI 1-97823, it seems that the contact point or the contact line between the support sleeve 104 and the shaft 105 to be measured is formed by pressing the support sleeve 104 in the direction from the outside of the support sleeve 104 to the center of the shaft 105 to be measured, and an induced current is applied to the contact point or the contact line, when the support sleeve 104 is fixed to the shaft 105 to be measured. However, if the support sleeve 104 is fixed in such a way, distortion occurs in both the support sleeve 104 and the measurement sleeve 101 to which the support sleeve 104 is fixed. As a result, there is the possibility that a correct value cannot be obtained as a torque sensor. In the meantime, if copper or silver solder is used for the fixing operation, an eddy current occurs in the place where the solder is used, which leads to weakness of an excitation magnetic field. Accordingly, the sensitivity as a torque sensor is expected to be degraded.
In a magnetostrictive material field, an annealing process is said to be effective as the method for eliminating the residual stress of the magnetostrictive material and for improving the sensitivity of the magnetostrictive material by making crystal grains larger. The patent gazette TOKKAIHEI 1-97823 does not disclose the annealing process. However, if the annealing process is assumed to be performed for the torque sensor disclosed by the patent gazette TOKKAIHEI 1-97823, the following two methods can be considered.
(1) After the annealing process is performed in the state where the measurement sleeve 101 is fixed to the support sleeve 104, they are fixed to the shaft to be measured. PA1 (2) After the measurement sleeve 101 is fixed to the support sleeve 104 and both of them are fixed to the shaft 105 to be measured, the annealing process is performed for the whole of the sensor including the shaft 105 to be measured.
Although the residual stress of the magnetostrictive material is eliminated and its sensitivity is improved with the annealing process in the above described (1), the support sleeve 104 and the shaft 105 to be measured are fixed by being welded using induction heating or by being soldered in a later process. Therefore, the temperature of the torque sensor becomes high in a wide range, and the residual stress can possibly and again occur in the magnetostrictive material. In the meantime, since the annealing process is performed at a final stage in the above described (2), the residual stress of the magnetostrictive material is eliminated and its sensitivity is improved. However, since the annealing process is also performed for the shaft 105 to be measured, the shaft 105 to be measured is damaged by the heat of the annealing process. As is often the case, a parts maker for manufacturing a torque sensor and an assembling maker for installing the torque sensor to a shaft differ. If the method referred to in (2) is adopted in this case, the assembling maker must perform the annealing process. As a result, it is inconvenient for the assembling maker. Therefore, the assembling maker may demand delivery of a torque sensor for which the annealing process is not required after installation to a shaft.

Kabushiki Kaisha Toyoda Jidoshokki Seisakusho


A solar cell includes a first conductivity type silicon substrate, a second conductivity type layer of microcrystalline or amorphous silicon deposited on the substrate in a plasma process and consuming an oxide film no more than 2 nanometers thick formed on the substrate before depositing the second conductivity type layer, a transparent electrode layer disposed on the second conductivity type layer, a grid electrode disposed on the transparent electrode layer, and an electrode disposed on the substrate. A method for producing a solar cell includes forming a silicon oxide film on a first conductivity type silicon substrate to a thickness not exceeding 2 nanometers by immersing the substrate in heated nitric acid, depositing a second conductivity type layer of microcrystalline or amorphous silicon on the silicon oxide film in a plasma, the silicon oxide film being consumed during deposition of the second conductivity type layer, and forming respective electrodes on the substrate and the second conductivity type layer.

FIG. 1 is a cross-sectional view of a prior art tandem solar cell comprising an a-Si:H (hydrogenated amorphous silicon) n-i-p solar cell serially arranged on an a-Si:H/c-Si (crystalline silicon) solar cell disclosed in "Proceedings Of The 2nd International Photovoltaic Science And Engineering Conference", 1986, pages 394-397. A p-type crystalline silicon or polycrystalline silicon (poly-Si) substrate 1 has serially disposed on it an n-type hydrogenated amorphous silicon layer 3, a p-type a-Si:H layer 7, an intrinsic a-Si:H layer 8, an n-type a-Si:H layer 3a, and a transparent electrode layer 4. Grid electrodes 5 are selectively disposed on the transparent electrode layer 4 and a rear surface electrode layer 6 is disposed on the rear surface of the substrate 1.
The n-type a-Si:H layer 3, p-type a-Si:H layer 7, intrinsic a-Si:H layer 8, and n-type a-Si:H layer 3a are successively deposited on the p-type c-Si or poly-Si substrate 1 in a plasma chemical vapor deposition (CVD) process. The tandem structure includes an n-i-p solar cell comprising a-Si:H layers 3a, 8, and 7 serially connected with an n-type a-Si:H/p-type c-Si or poly-Si solar cell. An ITO (indium tin oxide) transparent electrode layer 4 is deposited on the n-type a-Si:H layer 3a by sputtering or evaporation. The grid electrodes 5, comprising silver and having a spacing of several centimeters, are printed on the transparent electrode layer 4. The rear surface electrode layer 6 is formed by sintering an aluminum paste applied to the rear surface of the substrate 1 before the a-Si:H layers are deposited.
In this tandem solar cell, light of relatively short wavelengths within the solar spectrum is converted into electricity by the n-i-p solar cell comprising the a-Si:H layers, and light that passes through the n-i-p solar cell is converted into electricity by the n-type a-Si:H/p-type c-Si or poly-Si solar cell. Thus, a wide range of the solar spectrum is utilized to generate electricity in the tandem solar cell.
FIG. 2 is a cross-sectional view of a prior art silicon microcrystalline (.mu.c-Si:H) or a-Si:H/c-Si or poly-Si solar cell. An n-type c-Si or poly-Si substrate of 400 to 500 microns thickness has deposited on it a p-type .mu.c-Si:H layer or an a-Si:H layer 3 100 to 200 angstroms thick and a transparent electrode layer 4. A comb-type electrode 5 is disposed on the transparent electrode 4 and a rear surface electrode 6 comprising silver 6,000 angstroms thick is disposed on the rear surface of the substrate 1.
The p-type .mu.c-Si:H layer or a-Si:H layer 3 is deposited on an n-type c-Si or poly-Si substrate 1 in a plasma CVD process and the transparent electrode layer 4 is deposited by sputtering or evaporation. The rear surface electrode 6 is deposited on the rear surface of the substrate 1 and the grid electrodes 5 are deposited on the transparent electrode 4 by printing or evaporation.
In this .mu.c-Si:H or a-Si:H/c-Si or poly-Si solar cell, a pn junction is present between the n-type c-Si or poly-Si substrate 1 and the p-type .mu.c-Si:H layer 3. When sunlight is incident on the device, holes are produced in the substrate 1 and collected as a result of the potential gradient of the pn junction, thereby generating electricity.
FIG. 3 is a cross-sectional view of a MIS-type solar cell disclosed in "15th IEEE Photovoltaic Specialists Conference", 1981, pages 1405-1408. A p-type c-Si or poly-Si substrate 1 bears an oxide film 2. A collecting electrode layer 5 is disposed on the oxide film 2. A rear surface electrode layer 6 is disposed on the rear surface of the substrate 1.
The oxide film 2 is formed on the c-Si or poly-Si substrate 1 by thermal oxidation. An aluminum layer is deposited on the oxide film 2 by evaporation or sputtering and patterned by photolithography into a grid configuration having a spacing between grid fingers of several microns several tens of microns. The rear surface electrode 6 is formed by sintering aluminum paste which is deposited on the rear surface of the substrate before the oxide film 2 and the electrode layer 5 are formed. Metal M of the grid electrode pattern with the thin oxide film I and the c-Si or poly-Si substrate S comprise an MIS structure that generates electricity from light absorbed by the Si substrate. The range of the solar spectrum absorbed by the MIS structure is narrower than the range absorbed by the tandem structure.
In the prior art a-Si/c-Si or poly-Si solar cell constructed as described above, no matter how the c-Si or poly-Si substrate is cleaned, an interface state density of about 10.sup.9 eV.sup.-1 cm.sup.-2 is present at the a-Si:H layer/c-Si or poly-Si junction interface, limiting the open circuit voltage V.sub.oc. Furthermore, the open circuit voltage and the fill factor, i.e., the product of the current and the voltage corresponding to the optimum operation point of the solar cell divided by the product of the open circuit voltage V.sub.oc and the short circuit current J.sub.sc, are lowered because the a-Si:H layer/c-Si or poly-Si interface is affected by the plasma in the plasma CVD process, increasing the interface state density. In addition, optical and electrical deterioration, such as the Staebler-Wronski effect, occurs, especially in the neighborhood of the interface, when light irradiates the cell for a long time.
There is no established theory explaining the cause of the degradation of cell performance. However, the following theory is advanced. Generally, in a-Si:H and .mu.c-Si:H, silicon bonds which are not compensated by hydrogen are so-called "dangling" bonds. Since no atom is present at the end of a dangling bond, traps occur, adversely affecting the electrical characteristics of the non-crystalline silicon. In order to compensate the dangling bonds, hydrogen is added to the non-crystalline silicon and couples with the dangling bonds. However, when light irradiates the silicon, the hydrogen-silicon bonds are broken, resulting in degradation of the solar cell characteristics.
When an a-Si:H n-i-p solar cell is disposed on the a-Si:H/c-Si or poly-Si solar cell, in the tandem solar cell of FIG. 1, the same current must flow through both cells. Since the upper a-Si:H n-i-p solar cell has a smaller current output than the lower solar cell, the total output current is limited by the upper n-i-p solar cell. In the prior art .mu.c-Si:H/c-Si or poly-Si solar cell, the solar cell characteristics, such as open circuit voltage, short-circuit current, fill factor, and the like, are not always good. In the prior art MIS solar cell, to make sufficient light incident on the c-Si or poly-Si substrate, patterning of a fine metal electrode having a width of 5 to 15 microns and a spacing interval of 50 to 120 microns is required. That patterning requires an expensive process, such as photolithography.

Solar cell and method of producing the solar cell


Active amino acid Ca, i.e., calcium oxide and/or hydroxide product coexistent with a slight amount of one or more amino acids and/or hydrolyzable amino acid derivatives is disclosed, which can be effectively absorbed into the human body and can deposit onto the bone with a high efficiency. Beverages containing same are also disclosed. The active amino acid Ca product is produced by calcining a calcium-containing material at 800.degree.-980.degree. C. in a calcining chamber free from oxygen, and subjecting the calcined product to a forced cooling step.

This invention relates to an active amino acid Ca product, i.e., a calcium oxide and/or calcium hydroxide product coexistent with a slight amount of one or more amino acids and hydrolyzable amino acid derivatives, beverages containing same, and a process for their production. More particularly, it relates to an active amino acid Ca of natural origin coexistent with a slight amount of one or more amino acids and hydrolyzable amino acid derivatives, which can be effectively absorbed into the human body and can deposit onto the bone with a high efficiency, beverages containing same, and a process for their production.
It has been widely accepted that calcium is an essential element for formation of bone or tooth of mammals as well as human beings. In addition, it has recently been found that calcium is one of the most important elements that support all sorts of life activities and, at present, calcium is receiving much attention in the front line of medical science.
It has been pointed out that deficiency of calcium induces not only osteoporosis but such diseases as hypertension, arteriosclerosis, arthralgia, diabetes, immunological diseases, and obecity ["Kurasi To Kenkou (Life and Health)", 1991, vol.9, published by Hoken Doujin Sha].
However, calcium can be absorbed only at an extremely low absorption ratio unless it is ingested together with vitamin D or proteins, and a necessary amount of calcium can not be absorbed by independent ingestion of calcium.
Recent study has revealed that an adult requires calcium in an amount of 600 mg per day. It is known, however, that calcium contained in foods or beverages is not completely absorbed by the body and that calcium content indicated for a particular food or beverage is greatly different from the amount of calcium actually absorbed therefrom by the body. Therefore, an enormous amount of calcium-containing foods must be ingested in order to take up the necessary amount of calcium from daily meals.
For example, calcium contained in cow's milk which is known as a drink containing calcium at a level as high as about 100 mg/100 ml and is believed to be absorbed with a high absorption ratio due to bonding of calcium to protein, can be absorbed at a level as low as 50% at the highest, i.e., 50 mg out of 100 mg. In addition, the protein bonding to calcium finally produces, after being digested and absorbed, lactic acid, butyric acid, pyroracemic acid, sulfuric acid and phosphoric acid, and most of 50 mg of the absorbed calcium is consumed for neutralizing these acids, thus the amount of calcium substantially absorbed being at most about 10 mg out of 100 ml of cow's milk.
Therefore, it is obvious that a necessary amount of calcium can not be ingested from cow's milk alone. However, in order to supply the deficient amount of calcium from other foods or beverages, even calcium-rich foods such as small dried sardines, sardines, cystophyllum fusiforme, toasted laver, etc. fail to supply the necessary amount of calcium. As a result, human beings are always in a calcium-deficient state, thus suffering from the aforesaid diseases induced by deficiency of calcium.
Such situation is not limited to Japan alone. In Europe and the United States where cow's milk is consumed 3 to 5 times as much as in Japan, incidence of osteoporosis which has been clarified to be induced by deficiency of calcium is twice that in Japan. This fact shows that calcium-rich foods or beverages such as cow's milk are insufficient to solve the problem of calcium deficiency.
Vitamin D known to accelerate absorption of calcium is produced from provitamin D in the body through irradiation with sunlight, or is ingested directly from foods. The thus ingested vitamin D is converted to active vitamin D by the action of accessory thyroid hormone. The active vitamin D helps calcium to be absorbed through intestinal wall The active vitamin D also causes calcium of the bone to be released from the bone in cooperation with the accessory thyroid hormone and, as a result, excess vitamin D is known to induce many troubles such as hypercalcemia, uremia, and malacosteon. Thus, in the USA, FDA does not approve vitamin D a medicine.
As has been described above, even cow's milk, which is believed to show the best calcium absorption ratio, permits calcium contained therein to be absorbed only in an extremely small absorption ratio and, therefore, it is at present extremely difficult to supply a necessary amount of calcium from foods alone. The calcium absorption ratio decreases with age of men or women. It has been clarified that all sorts of diseases and senility are mostly induced by deficiency of calcium from both the microscopic (or cell-level) and macroscopic (or general) points of view (Reports of the Japanese Society of Internal Medicine, Apr., 1990).
That is, when calcium level becomes lower than is necessary for maintaining life, a necessary amount of calcium is supplied from the bone, which in turn damages the bone cells, inducing retardation of growth of bone or tooth and osteoporosis. In addition, general health state will be damaged. For example, purification of blood and healthy state of brain, nerve, heart, muscle, etc. will not be maintained.
Of these diseases, osteoporosis is believed to be the disease to which human beings are most susceptible due to deficiency of calcium. In addition, this disease has been found to produce bedridden old men and old patients suffering from dementia. Thus, it is the most important subject to solve the problem of calcium deficiency for realizing healthy longevity in the coming aging society.
In order to solve the problem of calcium deficiency, calcium-containing products have been developed as nutrition-supplying foods, and calcium-containing preparations for medical use have been required to show higher absorption ratio ["Karusiumu No Subete (Everything on Calcium)" written by Takuo Fujita, issued by Aki Shobo].
Of the calcium-containing products, that one which has been developed by the inventors and which is a purified electrolysis product of oystershell contains more mineral ingredients and shows a higher calcium ion concentration. This electrolysis product has been proved to show a markedly high absorption ratio in the intestines and deposits on the bone in a markedly high ratio, and is now actively employed in many medical facilities including hospitals attached to university as nutrition-supplying food for prophylaxis and treatment of diseases of adults.
In the course of further investigations on the aforesaid calcium-containing product to develop a calcium product showing a higher absorption ratio and a higher deposition ratio on the bone, the inventors have found that a novel active amino acid calcium oxide and/or calcium hydroxide product coexistent with an extremely small amount of amino acids (particularly, low molecular weight amino acids) and hydrolyzable amino acid derivatives can solve the aforesaid problem, thus having completed the present invention.

Active amino acid Ca, beverages containing same, and process for their production


A medical device includes an elongated medical device body; a first operating line and a second operating line inserted in an axial direction of the medical device body; and a bending operating part for performing a bending operation of a distal end part of the medical device body by pulling the first and second operating lines, at an intermediate part and a proximal end part in the axial direction of the medical device body, the first and second operating lines extending in parallel so as to be spaced apart from each other in a circumferential direction of the medical device body, and at the distal end part in the axial direction of the medical device body, the first and second operating lines being curved and joined together so as to approach each other in the circumferential direction of the medical device body gradually toward a distal end side.

As an elongated medical device, such as a catheter capable of bending a distal end part, a type having operating lines is known (for example, Patent Document 1).
In the catheter of Patent Document 1, a plurality of hollow tubes are disposed around a central lumen, and operating lines are respectively inserted through the two hollow tubes that face each other via the central lumen. In the catheter of this document, distal ends of the operating lines are fixed to the distal end part of the catheter. The catheter of this document is configured to bend rear ends of the operating lines. Accordingly, the distal end part of the catheter can be bent by selecting and pulling an operating line.

This patent is subject to a terminal disclaimer.


A mass flow controller includes a base having a first passage, an inlet portion for introducing fluid into the first passage, an outlet portion for releasing the fluid from the first passage, and a second passage branched from a first upstream portion of the first passage and connected to a second downstream portion of the first passage A mass flow sensor is connected to the first passage between the inlet portion of the base and the first portion of the first passage; A first valve is disposed in-line with the first passage between the first and second portions. The first valve controls the mass flow of the fluid passing through the first passage;. A second valve is disposed in-line with the second passage to opens/close the second passage. A valve controller compares the mass flow measured by the mass flow sensor to a standard flow, and then positions the first valve such that the measured mass flow corresponds to the standard flow.

1. Field of the Invention
The present invention relates to semiconductor device fabricating equipment that employs gas to process semiconductor substrates and the like. More particularly, the present invention relates to a mass flow controller of a gas supplying apparatus of semiconductor device fabricating equipment.
2. Description of the Related Art
Generally, various kinds of gases are used in semiconductor fabricating processes. A mass flow controller measures and controls the mass flows of the gases. Requirements for the accuracy of mass flow controllers have increased to meet the increasing demand for more highly integrated semiconductor devices.
FIG. 1 is a sectional view of a conventional mass flow controller, and FIG. 2 is a is an enlarged view of a mass flow sensor of the conventional mass flow controller.
Referring to FIGS. 1 and 2, a base 110 of the conventional mass flow controller 100 has a passage 112 through which a fluid passes, an inlet portion 114 for introducing the fluid into the passage 112, an outlet portion 116 for releasing the fluid from the passage 112.
A bypass 120 is disposed in the passage 112. The conventional mass flow controller 100 also has a sampling pipe 132 connected to the passage 112 between an inlet of the bypass 120 and an outlet of the bypass 120. Accordingly, a sample of the fluid flowing through the base 110 passes through the sampling pipe 132.
A mass flow sensor 130 measures a mass flow of the fluid passing through the sampling pipe 132 and hence, through the passage 112. The mass flow sensor 130 includes a first thermal resistance 134a and a second thermal resistance 134b wound around the sampling pipe 132. The first thermal resistance 134a and the second thermal resistance 134b include platinum (Pt) or other similar metals are connected to a bridge circuit 136. A control valve 140, e.g., a solenoid valve, is connected between the bypass 120 and the outlet end 116.
When the first thermal resistance 134a and the second thermal resistance 134b are heated, a temperature difference proportional to the mass flow of the fluid is generated between upstream and downstream ends of the sampling pipe 132. As a result, resistance values of the first thermal resistance 134a and the second thermal resistance 134b become different. The bridge circuit 136 detects the different resistance values as an electric signal. The detected signal is amplified through an amplifier (not shown). A compensator correlates the amplified signal to the mass flow of the fluid.
The measured signal indicating the mass flow of the fluid is transmitted to a valve controller (not shown). The valve controller compares the measured signal to a standard signal corresponding to a predetermined desired flow of the fluid. The valve controller moves the control valve 140 until the measured signal corresponds to the standard signal.
As mentioned above, this type of mass flow controller is widely used in apparatus for fabricating a semiconductor device. For example, the mass flow controller is used for controlling the supplying of a reaction gas in equipment in which a deposition process or an etching process is performed on a substrate.
When the mass flow controller malfunctions during the process, a main controller of the substrate processing equipment suspends the process. In particular, the main controller closes a plurality of valves mounted on a gas line through which the reacting gas passes. The substrate is unloaded from the substrate processing equipment. The reacting gas remaining in the gas line and the mass flow controller is then exhausted. Then, the mass flow controller is exchanged.
Accordingly, a gas supplying apparatus connected to the substrate processing equipment includes a purge line and a purge valve for exhausting the reacting gas that remains in the gas line and the mass flow controller. The purge line and the purge valve are connected to an inlet portion of the mass flow controller.
In addition, the control valve 140 of the mass flow controller is held open by current supplied to the control valve. On the contrary, the control valve 140 closes when the current is not supplied to the control valve. Thus, when the main controller cuts off the current to the control valve 140, the control valve 140 blocks the passage 112 in the base 10. Also, when the control valve 140 is experiencing trouble, the reacting gas remaining in the gas line and the mass flow controller is exhausted through only the purge line and the purge valve. However, the purge line and the purge valve contribute significantly to the volume and cost of the gas supplying apparatus

Substrate processing equipment having mass flow controller


An actuating and sensing apparatus includes a circuit board, a housing, an actuating device and a sensor. The housing is disposed on the circuit board and includes an entrance opening, an exit opening and a compartment. The compartment is in communication with an external environment of the housing through the entrance opening and the exit opening. The actuating device is disposed within the compartment and closing the exit opening. The sensor is disposed within the compartment and corresponding to the entrance opening. When the actuating device is enabled, a gas within the compartment is guided to the external environment outside the housing, and a pressure gradient is generated in the compartment so as to introduce a gas from the external environment outside the housing into the compartment through the entrance opening to make the gas detected by the sensor.

Nowadays, people pay much attention to monitoring environmental air quality in daily living, e.g., monitoring carbon monoxide, carbon dioxide, volatile organic compounds (VOC), PM2.5, and so on. The exposure of these substances in the environment can cause human health problems or can even harm the life. Therefore, it has become an important issue for every country to develop and implement environmental air quality monitoring technology.
However, the conventional environmental gas detector (e.g., the air cleaner) is bulky in volume and inconvenient to carry around. That is, it is difficult for the user to acquire the information of the ambient gas. Consequently, the user may be exposed to the environment containing the harmful gas. Therefore, it is important to acquire the information of the ambient gas everywhere and at any time.
Moreover, since the conventional environmental gas detector is not waterproof and dustproof, some problems occur. If moisture or liquid is introduced into the environmental gas detector during the process of transferring the gas, the outputted gas contains moisture. In case that the electronic component for sensing the gas is contacted with the gas, the electronic component is possibly damped, rusted or even damaged. Moreover, the conventional environmental gas detector is not dustproof. If dust is introduced into the environmental gas detector during the process of transferring the gas, the components are possibly damaged and the gas transportation efficiency is reduced. Therefore, it is important to achieving the waterproof and dustproof efficacy of the environmental gas detector.
For solving the above drawbacks, it is important to provide a miniature, silent, waterproof and dustproof actuating and sensing apparatus.

Actuating and sensing apparatus and casing using the same


An audio signal processing apparatus includes a signal processing unit, an output unit, a retention unit, and a coefficient setting unit. The signal processing unit is configured to perform signal processing on an audio signal by a digital filter. The output unit is configured to be connected to an external speaker and output the audio signal to the speaker. The retention unit is configured to retain a plurality of filter coefficients that are impulse responses having reverse characteristics of a plurality of speakers having different speaker characteristics. The coefficient setting unit is configured to select one of the filter coefficients that corresponds to the speaker connected to the output unit from the retention unit and set the filter coefficient in the digital filter.

The present disclosure relates to an audio signal processing apparatus and an audio signal processing method that perform correction processing on audio signals to correct speaker characteristics.
In devices that perform audio signal processing, such as acoustic devices (hereinafter, referred to as audio signal processing devices), there are techniques in which correction processing such as digital filter processing is performed on an audio signal acquired from a sound source. The audio signal processing device outputs an audio signal that has been subjected to correction processing from a speaker or the like, thus being capable of improving a sound quality of the audio output from the speaker or the like, acoustic effects, or the like.
Examples of such correction processing include correction of "speaker characteristics". The speaker characteristics refer to frequency characteristics of a speaker, which differ depending on a bore or the like of a speaker or an internal structure thereof. Here, the frequency characteristics refer to phase characteristics as deviation in time between phases of an audio signal input to the speaker and an audio signal output from the speaker, amplitude characteristics as an intensity ratio, or the like.
Examples of the audio signal processing device capable of correcting speaker characteristics by performing correction processing on an audio signal include a "signal processing apparatus" disclosed in Japanese Patent Application Laid-open No. 2009-55079 (paragraph [0034], FIG. 1; hereinafter, referred to as Patent Document 1), for example. This signal processing apparatus is intended to improve low-level components of a compact speaker by combining amplification of a low-frequency band signal of an input audio signal and its shift to a high frequency band.

Audio signal processing apparatus and audio signal processing method


A method for transporting a fluid, for instance gas under pressure, in a pipe while reducing head loss to a minimum, comprises injecting into the pipe a fraction of a liquid with a predetermined flow rate so that the combination formed by the gas flow and the injected liquid fraction has the form of a ring-shaped control flow over at least the length of the pipe, and on delivery separating the injected liquid fraction from the gas under pressure.

The present invention relates to a method for reducing friction phenomena between a flowing fluid and the wall of a pipe in which it is carried.
It is applicable to transportation of gas under pressure, particularly that of natural gas under pressure, by reducing the pressure losses resulting from friction phenomena.
It relates in particular to a method for transporting natural gas under pressure in the presence of a liquid fraction, whereby the flow of the gas plus the liquid fraction is annular over at least part of the length of the pipeline.
Transportation of natural gas under pressure represents an important economic issue and intercontinental gas pipelines require substantial investment outlays. The gas is generally transported over long distances, with the transportation pressure being approximately 70 bars in the case of a land line but as high as approximately 160 bars in the case of a sea line. In the majority of cases, the natural gas transported contains at least 90% methane.
The pressure losses resulting from friction between the gas in turbulent flow and the inside wall of the pipeline are large, due in particular to the long distances, and contribute to increasing the cost of production. Hence it is necessary to reduce these pressure losses.
One method for offsetting pressure losses resulting from these friction phenomena consists of installing recompression stations regularly spaced along the pipeline and regulated to offset pressure losses. Such an arrangement considerably increases the necessary investment outlay and entails high energy consumption and operating costs.
Moreover, for sea lines, the recompression process during transportation presents implementation difficulties.
The prior art describes the use of additives such as polymers added to the fluid to be carried in specific proportions to reduce friction phenomena.
The method described in U.S. Pat. No. 4,958,653 enables the friction-reducing additives added to a pipeline to be proportioned in such a way that the gas flowrate is maximized for fixed pressure loss conditions.
The principal teaching of this reference is based on a method principally involving the following steps: a gas is introduced into a line under pressure, a quantity of additives is injected at a first point in the line, the gas flowrate is checked at a second point in the line, and the quantity of additives injected at the first point is adjusted until the gas flowrate measured at the second point reaches a maximum value.
The additive also fills in the unevennesses in the inside wall of the pipeline and decreases friction phenomena by minimizing protuberances.
However, such a method does not enable the pressure loses to be minimized for a fixed gas flowrate.
To transport a viscous liquid such as crude petroleum, a method has been described consisting of adding a less-viscous liquid, for example water, which flows with the higher-viscosity liquid and thus reduces wall friction.
It has been discovered that, in the case of a gas flowing under pressure, it is possible to reduce the pressure loss by injecting a liquid that is more viscous than the gas transported, meeting conditions that produce annular flow, as described in French Application EN. 96/08,914.

Method of transporting gas under pressure in the presence of a liquid film


The objectives of the present invention are: to provide a novel tetrazole silane compound, a method for synthesizing the same, and a silane coupling agent containing the tetrazole silane compound as a component; and to provide a surface treatment solution using the tetrazole silane compound, a method for surface treatment, and a method for adhering two different materials. The tetrazole silane compound according to the present invention is a compound represented by chemical formula (I). (In formula (I), X, R, and n are respectively the same as defined in the specification.)

As a component of a silane coupling agent, an organic compound having a silicon atom in its molecule has been used. Such a substance has functional groups having different affinities in the molecule, and exhibits a function as an intermediary between organic materials and inorganic materials that are not normally compatible. Therefore, it is an essential agent for development and production of composite materials.
Patent Literature 1 proposes, as a component of a silane coupling agent used as a primer for bonding glass or metal to rubber, various substances having a structure where a nitrogen containing heterocyclic ring such as triazole or thiadiazole is connected to a silyl group such as a trimethoxysilyl group or a triethoxysilyl group, through an organic group having a thioether (sulfide) bond or the like.
Patent Literature 2 proposes 1N-trimethoxysilylpropyl-1,2,4-triazole as a silane compound used as a corrosion inhibitor for aluminum and magnesium alloys.

Tetrazole silane compound, method for synthesizing said compound and use thereof


An electrical facility includes an earphone socket having a housing which includes a socket opening at one end portion and a compartment in the other end portion and which includes one or more signal terminals and a ground terminal, and a connector mechanism is engaged in the compartment of the housing and includes a socket element directed toward and aligned with the socket opening of the housing, and includes an output terminal electrically connected to the socket element. The connector mechanism may be selected from an RF connector mechanism. The output terminal of the housing is directed toward an outer peripheral portion of the housing.

1. Field of the Invention
The present invention relates to an earphone socket or jack, and more particularly to an earphone socket including a radio frequency (RF) connector device for transmitting radio frequency signals in addition to the radio and/or vocal and/or audio signals.
2. Description of the Prior Art
Typical earphone sockets comprise a phone connector or audio connector including a phone jack or socket having a 3.5 mm socket opening formed or provided therein for plugging or receiving or engaging with the corresponding 3.5 mm phone plug or the like, in which the typical phone jack or socket is normally disposed or attached or mounted or secured in an electrical facility or apparatus, such as the mobile phone or portable phone, and normally includes a radio or audio module for AM/FM single receiving and/or transmitting purposes, compact disc processing purposes, MP3 processing purposes, or the like, and the phone plug is normally electrically connected or coupled to the earphone or the speaker or the like for outputting the radio or audio signals.
For example, U.S. Pat. No. 6,688,918 to Wang et al., U.S. Pat. No. 6,928,310 to Lee, U.S. Pat. No. 7,340,284 to Chung, and U.S. Pat. No. 7,940,339 to Horiachi disclose several of the typical electrical facilities or apparatuses comprising a phone plug for selectively engaging with the phone jack or socket of the electrical facility or apparatus.
However, the phone jacks or sockets and the phone plugs of the electrical facilities or apparatuses may be used for receiving and/or transmitting the radio or audio signals of relatively lower frequencies, and may not be used for receiving and/or transmitting the radio frequency (RF) signals of relatively higher or greater frequencies, such that an additional phone jack or socket and/or phone plug is further required be provided for receiving and/or transmitting the radio frequency (RF) signals of relatively higher or greater frequencies.
Furthermore, the radio frequency (RF) signals processing modules, such as Global Positioning System (GPS) modules, WiFi modules, digital video broadcasting terrestrial (DVB-T) modules, digital audio broadcasting modules, etc. have now been widely used for receiving and/or transmitting and/or processing the radio frequency (RF) signals which may not be used for receiving and/or transmitting the radio frequency (RF) signals of relatively higher or greater frequencies.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages of the conventional earphone sockets and/or phone plugs of the typical electrical facilities or apparatuses.

Earphone socket having RF connector device


An apparatus for preventing torque variation in a digitally controlled servomotor. Electrical angles .theta..sub.1 and .theta..sub.2 of the exciting magnetic field or the armature coil at respective timings of detecting and controlling a load current are obtained. The current is dq-transformed with .theta..sub.1 and inverse-dq-transformed with .theta..sub.2. As a result, even if there is a displacement of the actual electrical angle owing to the rotation of the armature during computing, it is possible to execute accurate current control. Further, at the time of calibration of the control system, the load currents are detected to be dq-transformed. From the d-axis components and q-axis components, values related to the offset and the amplification factor of the current detection systems are calculated. During the actual operation of the servomotor, the detected current value is corrected using the values. Further, the detection of the load current is performed plural times in one control cycle. Thereupon, a statistical average value is obtained as the detected current. Accordingly, an undesirable variation of the output torque is prevented.

1. Field of the Invention
The present invention relates to a digital servo-control apparatus for digitally controlling an AC servomotor and, more particularly, relates to apparatus adapted for preventing the output torque of the servomotor from fluctuating.
2. Description of the prior art
In order to avoid difficulties involved in analog control systems, a digital servo-control apparatus has recently come into use. In the digital servo-control apparatus, the target value and the feedback value are provided as digital values and the difference therebetween is calculated by a digital computer. Further, the command value according to the difference is provided as a digital value and the controlled amount (rotational angle, rotational velocity, or load current) to a controlled system, i.e., a servomotor is digitally controlled by the command value. Such servo-control apparatus, in general, have the feedback loops for a position, a velocity, and a current.
In the current feedback loop of such feedback loops, the load current is detected by a current transformer (CT), the output thereof is amplified by an analog amplifier, and the output thereof is sampled at intervals of a predetermined period to be digitized. The detected current of each phase is subjected to a dq-transformation. The load current supplied to the servomotor is feedback-controlled so that the resultant d-axis component and q-axis component of the detected current become equal to the respective target values.
The d-axis component of the load current represents the reactive current, while the q-axis component is proportional to the output torque of the servomotor when the servomotor is a synchronous motor and the strength of the exciting magnetic field is constant. Accordingly, when the servomotor is a synchronous motor, the feedback control of the load current is executed so that the d-axis component of the detected load current becomes zero and the detected q-axis component becomes equal to the target current proportional to the target output torque.
As described above, the d-axis component and the q-axis component have only DC components, respectively, regardless of the electrical angle, i.e., the phase angle of the load current. Accordingly, the dq-transformation method has an advantage that the current control to the servomotor becomes easier. Here, the electrical angle is defined as the angle formed between the exciting magnetic field and the reference axis of the armature coil in the case of a synchronous motor. More concretely, the electrical angle is, for example, the rotational angle of the revolving magnetic field in a revolving-field type synchronous motor, the rotational angle of the armature in a revolving-armature type synchronous motor, or the rotational angle of the revolving magnetic field referenced from the primary side (stationary coordinate system) in an induction motor.
In performing the above described dq-transformation of the detected load current and the inverse dq-transformation for getting a command value of current from the command values of the dq-components, the electrical angle must be given. The electrical angle is generally assumed to be constant during the control period of the velocity feedback loop.
Therefore, in the conventional apparatus, the same assumed electrical angle is used in both dq-transformation of the detected load current and inverse dq-transformation for getting the command value. However, the actual electrical angle at which the command value is output is advanced with respect to the assumed electrical angle because of computing time by the digital computer. Accordingly, the conventional apparatus has a problem that the difference between the actual electrical angle and the assumed electrical angle used in the control of the servomotor becomes large and, hence, it becomes unable to obtain an accurate command value of the phase current to be controlled. Because of this, the conventional system has a problem that the output torque of the servomotor tends to fluctuate.
The d-axis component and the q-axis component of the load current are essentially direct currents independent of the frequency of rotation of the revolving magnetic field or the revolving armature.
However, it has been found by the present inventors that the d-axis component is, in reality, not zero but has a DC component, a fundamental wave with the same frequency as the frequency of rotation of the revolving magnetic field or the revolving armature, and a second harmonic, as shown in FIG. 7, and the q-axis component has a DC component not corresponding to the output torque of the servomotor, a fundamental wave with the same frequency as the frequency of rotation of the revolving field or the revolving armature, and a second harmonic, as shown in FIG. 8.
In the feedback control, the load current is controlled according to the instantaneous values of the d-axis component and the q-axis component of the load current detected at intervals of a predetermined period and the target values of the same. Therefore, the power-factor decreases when there is an error in the DC component of the d-axis component of the detected load current, and the power-factor varies when there is a fluctuation in the d-axis component. Further, there is such a problem that the response speed tends to vary when there is an error in the DC component of the q-axis component and the output torque tends to fluctuate when there is fluctuation in the q-axis component.
Further, the sampling of the load current in the above described current feedback loop is performed only once when the PWM voltage applied to the servomotor is zero as shown in the timing chart of FIG. 11, or at the middle point of the control period of the current feedback loop. Even if the sampled value of current happened to be abnormal, the sampled value is used as the feedback value of the current feedback loop and calculation of the command value of current is performed according to the sampled value. Therefore, the conventional servo-control has a problem that the PWM voltage swings and the torque or velocity variation becomes greater.

Digital servo-control apparatus for preventing torque variations


A sculptured diaphragm of a sensor is fabricated by providing a semiconductor material, forming at least one cavity on the front side of the semiconductor material, forming a diaphragm layer over the semiconductor material, and the etching a cavity on the back side of the semiconductor material. If a sensor having a diaphragm with a central boss is desired, then the diaphragm layer is planarized to form a thick and a thin portion in the diaphragm layer.

The present invention relates in general to semiconductor devices and, more particularly, a method of forming a sculptured diaphragm.
Semiconductor sensors are comprised of thin diaphragm formed on a semiconductor substrate. The diaphragm is typically formed by etching the back side of a semiconductor substrate to form a cavity and leaving a thin layer of semiconductor material to act as the diaphragm.
The deformation or movement of the diaphragm causes a change in capacitance or resistance. In order to respond to low pressures, the diaphragm thickness is reduced. However, a thin diaphragm causes more nonlinearities to occur in the output due to the presence of nonlinear membrane stresses present on the surface of the diaphragm.
To reduce the nonlinearity, a diaphragm of variable thickness is desirable. Such diaphragms have been fabricated by making certain portions of the diaphragm thicker than others. The thicker portions of the diaphragm are called bosses. This approach allows the fabrication of high output, low pressure sensors with substantially linear outputs.
It would therefore be advantageous to be able to fabricate a sensor with a diaphragm having a thick central boss in a cost competitive manner.

Method for making a sculptured diaphragm