A piston pump having a piston axially movable against the force of a spring within an operating chamber connected via check valves to an operating cylinder and a hydraulic medium supply. A section of the piston that extends into the operating chamber has a reduced diameter extension which extends from a shoulder of the piston that delimits the operating chamber. The extension includes a thickened free end having a sealing surface facing the shoulder. A valve disk is located and guided on the extension in a gap between the shoulder and sealing surface and is capable of axially reciprocating movements thereon. The valve disk is provided with openings which provide a passageway for hydraulic medium from the operating chamber to a second check valve. The openings are blocked when the valve disk abuts the sealing surface.

The invention concerns a piston pump with a pump housing and a piston, which, with its end surface and the pump cylinder delimits a displacement chamber, which is connected to a hydraulic medium supply via a first check valve and to an operating cylinder via a second check valve, wherein the piston moves axially in reciprocating fashion from one end position of the largest displacement volume to the other end position of the smallest displacement volume against the force of a spring. The invention especially pertains to a hydraulic pump for powering hydraulic tools.
Piston pumps of this type are generally known and also serve to power pressing tools with high and very high pressures. Battery-operated drive motors with limited torque are often used for the mobile operation of such tools. In this context, the maximum pressure that can be produced in a pump of this type is also limited, since the torque produces the maximum force with which the piston can be driven in the pump cylinder.
The task of the invention is to improve a piston pump of the initially mentioned type so that higher pressures can be attained at equal maximum torque. Nonetheless, the pump should be configured in a simple manner.
The problem is solved according to the invention in that the section of the piston that extends into the displacement chamber is provided with an extension with a smaller diameter that connects to the end face of the piston via a shoulder and that has a thickened free end of the piston with a sealing surface facing said shoulder; in that a valve disk, which acts as a seal, is present between the shoulder and the sealing surface, which is brought into the pump cylinder, and through which the connection of the displacement chamber to the second valve is capable of being closed. The axial thickness of the valve disk is smaller than the gap between the sealing surface and the shoulder, so that the valve disk can be moved back and forth between the shoulder and the sealing surface, while the valve disk is provided with at least one opening through which the displacement chamber can be connected with the second check valve and which is closed when the valve disk is brought into contact with the sealing surface. Such a valve disk that is movable on the piston extension can be used to form a pump that operates in two stages, and which creates a high volume flow at relatively low pressures through the movement of the thickened end of the piston in the pump cylinder.
At relatively higher pressures, the return spring cannot completely retract the thickened end of the piston, against the pressure in the operating cylinder, and accordingly also the pressure in the displacement chamber. The displacement chamber further exhibits a stop on which, in a position of the piston between the end positions, the valve disk lies. Through the valve disk a small displacement chamber is formed that is only pressurized with the pressure of the shoulder surface of the piston. The free surface of the shoulder is provided to be smaller than the effective surface of the thickened end of the piston. In this way, the piston can produce higher pressure at the same torque and power. The operating method is described in detail below with reference to the drawings.
It is practical that, if the thickened end of the piston features a circumferential collar, the side of it, which faces toward the step, forms the sealing surface. The spring that rests on the side of the displacement chamber that lies across from the piston can engage the side of the collar that lies across from the sealing surface. In this manner a relatively large and powerful spring can be integrated into the displacement chamber so that correspondingly high pressures can be produced.
According to a preferred embodiment of the invention, the thickened end of the piston is configured as a hat-shaped piston sleeve that is mounted on the extension. Preferably the piston sleeve is mounted on the extension in such a way that it can be removed. In general, the piston unit is made up of three individual parts, the piston with the extension, the valve disk, and the piston sleeve, which are easy and inexpensive to produce. The piston sleeve can also be movable on the extension, as long as it can be ensured that a gap between the valve disk and the sealing surface or the step remains that depends on position. This gap can be very small, as long as the hydraulic medium can flow through it.
The piston can generally be driven as desired. It is practical if the piston is driven by a cam without guide rings. This has the advantage that freewheeling is possible in the direction of the bottom dead center, which is necessary because of the two-stage operating method, since the piston stands still at an intermediate point. The cam only operates during the compression phase in the direction of top dead center.
According to another embodiment of the invention, it is provided that the piston move within a sleeve that is inserted in the pump housing. This has the advantage that the piston unit with the return spring can be installed into a cylindrical displacement chamber of the pump housing, which is restricted by the sleeve in the downward direction. At the same time, this sleeve can form the stop for the valve disk, which is directly retained in the cylindrical recess of the pump housing while acting as a seal.
Generally, it is also possible that the valve disk is guided by the sleeve, set into the pump housing, that extends in the direction of the operating cylinder, while forming the stop for the valve disk. This has the advantage that the sleeve can be optimally fitted to the guide of the piston, on the one hand, and to the guide of the valve disk, on the other. Both measures allow the sleeve to consist of a different material than that of the piston and/or that of the pump housing.


A magneto-optical recording medium on which new information can be directly over-written over pre-existing recorded information. Such medium comprises two magneto-optical recording layers which have a difference in Curie temperature in the range of 0.degree. C. -25.degree. C. and which are separated from each other by a metal layer for the transfer of heat, such as aluminum. Recording is effected by scanning the medium with a write spot produced by a pulsed laser beam concurrently with application of an external magnetic field which is modulated in accordance with the information to be recorded. The layers may have equal Curie temperatures if they behave thermally asymmetrically. At any scanning position of the write spot the scanned superposed local areas of the two recording layers are heated thereby above the Curie temperature of at least one of such layers and then permitted to cool while being subjected to the external magnetic field. This produces a frozen-in net magnetization in the scanned local area of one of the recording layers, which aids the external magnetic field in producing a similar frozen-in net magnetization of the superposed local area in the other recording layer. This allows use of a relatively weak external magnetic field, which is more economical and capable of operation at higher frequencies. Any pre-existing magnetization of the latter superposed local area is erased in consequence of magnetization thereof in accordance with the external magnetic field.

1. Field of the Invention
The invention relates to an erasable magneto-optical recording medium comprising a substrate on one side of which there is provided a first magneto-optical recording layer having a first Curie temperature and a second magneto-optical recording layer having a second Curie temperature, such layers having an easy axis of magnetization perpendicular to the plane of the layer, superposed information bits in the form of magnetic domains being inscribable in both layers by a combination of irradiation with laser light and a modulated magnetic field.
The invention also relates to a method of simultaneously erasing existing information and inscribing new information in such a magneto-optical recording medium.
2. Description of the Related Art
In a MO (=magneto-optical) recording medium, data are represented by magnetized domains or bits. The direction of magnetization of the domains extends perpendicularly to the plane of the MO-recording layer. The bits can be detected by means of the MO-effect, which causes the direction of polarization of polarized light to change as a function of the direction of magnetization of the domains when such light is reflected from (Kerr-effect) or passed through (Faraday-effect) the layer.
The magnetized domains are obtained by locally heating the MO-recording layer by means of a focused laser light beam to a temperature above the Curie temperature of the material of the MO-recording layer. During cooling to a temperature below the Curie temperature, the magnetization is locally oriented according to the direction of an externally applied magnetic field and then becomes frozen-in. This method is also termed thermomagnetic recording. A customary manner of inscribing information in a MO-recording layer consists in rotating a disc-shaped recording medium while a permanent external magnetic field is applied. A laser light beam which is modulated according to the information to be recorded inscribe inscribes magnetic domains in the MO-recording layer. A disadvantage of said laser-modulation method is that the existing information cannot be directly overwritten with new information. The existing information must first be erased, by using a permanent magnetic field and a continuous laser light beam. A suitable method of directly overwriting existing information with new information (termed direct overwrite) is magnetic field modulation (MFM). In MFM it is the external magnetic field which is modulated according to the information to be recorded, the focused laser light beam having a constant power. The external magnetic field is generated by a magnet coil.
In the case of MO-recording using MFM, a MO-recording layer is desired whose direction of magnetization can change at weak magnetic fields, because this enables the dissipation of the magnet coil to be reduced and/or the distance of the magnet coil to the MO-recording layer to be enlarged. Technically, it is very difficult to generate a strong magnetic field having a high frequency (in the order of magnitude of 10 MHz).
In European Patent Application EP-A-225141 a description is given of such a magneto-optical recording medium which is suitable for direct overwriting. In said Application, use is made of two "exchange"-coupled MO-layers which have an opposite magnetization at temperatures between room temperature and the Curie temperature, so that the opposing demagnetizing fields are small and the MO-layer can be inscribed with a smaller external magnetic field. In this known MO-recording medium, both MO-layers have an opposite direction of magnetization. Also the superposed domains have opposite directions of magnetization.
A disadvantage of the known MO-recording medium resides in the fact that the technology used for the manufacture of the exchange-coupled MO-layers is difficult to control. Said MO-layers are provided on a substrate by means of vacuum evaporation or sputtering. The exchange-coupling acts over only a few interatomic distances, so that any contamination or oxidation of the first MO-layer substantially reduces the exchange-coupling with the second MO-layer.

Direct over-write magneto-optical recording medium having multiple recording layers, and method of recording new information by directly overwriting pre-existing recorded information on such medium


An improved two roll sugarcane crushing mill with a semi closed frame having a plurality of improved two roll mill modules in tandem. Each improved two roll mill modules has a bottom roll and top roll, the bottom roll being rotatingly mounted in a pair of main frames at the two ends and the top roll is rotatingly mounted in a pair of top beams. One end of each of the top beams being pivotedly attached near the upper end of the main frame towards feed side for swinging the top beams along with the top roll. A hydraulic loader is provided which is pivotally attached between the end of the top beam and the base of the main frame. The semi closed frame fitted at the bottom end to the base of the Head Stock is designed to bear the forces of heavy and fluctuating loads.

1. Field of the Invention
The present invention relates to an Improved Two Roll Sugarcane-crushing Mill. More particularly this invention relates to the said Improved Two Roller Sugarcane crushing Mill having a semi closed frame invented for operational convenience sturdiness and improved performance.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98.
In the prior art, the inventor of the present invention has fully described and claimed an improved two roller sugarcane crushing mill in his Indian patent No. 186646. Several corresponding foreign patents in countries like US, South Africa, ARIPO etc. also have been granted. The two roller crushing mill claimed in the said patent had distinct advantages as enumerated in the specification of the said patent over the earlier crushing mills. In the said mill a single or plurality of feeder rollers of toothed or Cast iron type are used, without needing a closed stationary pressure chute for compressed/compact feeding of prepared cane/bagasse mat and in which, pivoted hydraulic system attached to a lever arm for free floating top roll is provided to give more loading at less hydraulic pressure and at the same time easy dismantling of top rolls, and reduced hydraulic seal failure resulting into low maintenance cost, less power consumption and improved performance, as of existing mill.
Although the said two roller mill claimed in the said patent by the same inventor had distinct advantages, during installation and its working it was observed that, it had following limitations which needed to be improved.                1. There was further scope to strengthen the headstock frame in the said mill.        2. There was further scope for better arrangement for side supporting of the Bottom roll Bearing.        3. Provision of better locking arrangement for the Bottom roll Bearing with bolting arrangement was desired.        4. Provisions were necessary for easy assembly/dismantling of Bottom roll without removing the Top roll.        5. Taper wedges needed to be eliminated for providing strength and reducing stresses in the headstock frame and convenience for operation as well as maintenance        6. Provision of imbibition or maceration liquid feeding means was required on the scraper for feeding the imbibition/maceration liquid to the bagasse mat for increased extraction efficiency.        7. Forcing zig-zag travel of the bagasse mat for providing better permeability for improved extraction efficiency.


Systems and methods for quickly resolving storage area commands from packet addresses are presented. Clients exchange packets comprising addresses and payloads with physical storage areas that have controllers using a stateless protocol. Modules use the addresses in addition to payloads to derive commands that are understandable by the controller. Furthermore, the neither the module nor the controller require use of a file system to interact with the physical storage area. Modules can derive the storage area commands through resolving a context associated with physical storage area. In some embodiments, modules split addresses into portions that can be used as indices into context lookup tables. In other embodiments, modules can employ variants to router address lookup algorithms to quickly resolve storage area commands.

Network storage devices require high performance to ensure a user or an application experiences fast response or high data throughput from the storage device. Client computers exchange packets with the storage devices where each packet comprises information directed toward a physical storage area. Typically, the information includes addresses, payloads, commands, or other information relevant to interacting with the storage area. High performance network storage solutions imply the various aspects of the solution should also be high performance including processing protocols, interpreting packet information, command resolution, addressing storage areas, or other aspects.
The faster a network storage solution is able to process networking protocols the higher the performance of the solution. Some storage solutions use stateful protocols including TCP or iSCSI over TCP to communicate with network storage devices. Stateful protocols incur overhead when processing packets at high speeds often times requiring additional support systems include TCP Offload Engines (TOE) to improve performance. As networking infrastructure speeds increase, the overhead on stateful processing places greater demands the processing units to maintain state of a communication link. To alleviate the problem of protocol overhead and to improve performance, a network storage solution could employ stateless protocols. Solutions that employ open standard ATA over Ethernet (AoE) use Ethernet as the stateless protocol. Such solutions offer high performance on communication networks; however, the solutions do not offer addressing schemes that can scale to extended network, for example, a LAN, WAN, or the internet using layer 3 routing.
Constituent storage elements of a networks storage solution including clients, storage devices, proxies, or other equipment, should quickly interpret commands to ensure performance of the solution remains high. Traditionally, solutions employ a command protocol imposed on a communication stack. Again, take for example iSCSI where the SCSI command set tunneled over a TCP/IP connection between a client and storage device. This implies, once a storage element receives packet, it must continue to process the command protocol above and beyond protocol processing. Through proper construction of the network storage solution, packet interpretation can be advantageously accelerated by having the communication link processing take some of the responsibilities. Furthermore, communication link processing can aid in the resolution of storage area commands.
In general, network storage solutions provide explicit identifiers (IDs) associated with a physical storage area. For example, a logical volume of storage based on iSCSI has a logical unit number (LUN), or a NAS system has a path or file name on the NAS file server. However, this imposes a completely separate storage area ID translation layer on top of a communication layer when packets are exchanged over a network. The storage device decodes the ID to determine which physical storage area is the target. For example, a LUN refers to a logical volume; however, storage devices resolve the LUN to a disk or a disk partition as a function of other packet information including a logical block address (LBA) or other payload information. Once the address has been translated, the commands must then be interpreted. Therefore it is advantageous to address physical storage areas utilizing networking infrastructure rather than solely using an explicit address or ID because the network itself can help resolve an address to the storage area. Furthermore, it is also advantageous to use physical storage area addresses to help resolve a command targeting the storage area. For example, if an IP address is used as an address for a storage area, network switches or routers find the storage area by directing network storage packets appropriately without using additional extraneous infrastructure to create the storage fabric. The use of IP addresses as storage area addresses is well addressed in co-owned Zetera U.S. patent applications with Ser. Nos. 10/473,713, 10/473,509, 10/47280, and 10/763,099 which are hereby included by reference in their entirety.
Using externally controlled addresses for storage areas provide advantages of scalability because the addresses of storage areas are not necessarily bound to hardware or to physical location. However, the address space can be quite large. For an IPv4 address, there are over 4 billion addresses that could be assigned to a storage area. For an IPv6 address, there are 3.4×1038 addresses that could be assigned to a storage area. Without a storage device knowing a priori what addresses are going to be assigned to its storage areas, the storage device might not be able to assume restrictions on the address space resulting the storage device having to search for the correct storage area through the entire address space. For example, if storage devices manage storage areas having IP addresses from multiple subnets spread evenly the full address space; each storage device can not assume limitations on subnets to reduce the search space thereby consuming memory. Therefore, the storage device requires a fast method for resolving a storage area's address to the storage area context where the method balances memory utilization with speed of resolution.
Consumers of network storage have an insatiable need for storage. In the near future one could reasonably expect that all electronic data, communications, content, or other data will be stored for archival purposes and will not be deleted. Therefore, storage addresses should scale with the storage solutions to support nearly seamless increases in capacity, performance, reliability, recovery, or in other critical characteristics. For example, a logical volume represented by a multicast address could store data on a storage area that individually have addresses comprising one or more segments including the multicast address, LBA, port assignment, time stamp, or other information in a network storage packet. Complex addresses loaded with information are difficult to interpret forcing storage devices to consume CPU time that might be precious on cost sensitive storage devices.
Therefore, there remains a considerable need for apparatus and methods to ensure high performance of network storage solutions. High performance network solutions would comprise the following beneficial elements:                Exchange packets between storage elements and storage areas using a stateless protocol        Modules use addresses within the packets to quickly derive storage area commands without requiring a file system

Systems and methods for deriving storage area commands


An integrated PCN/DCN system architecture has a switching center, coupled to a public switched telephone network (PSTN), which selectively transfers signals between the PSTN and a digital cellular network (DCN) or a personal communications network (PCN) which is allocated a portion of the cellular communications band by a local cellular operator. Each PCN subnetwork of the PCN includes several microcells arranged in a multi-dimensional grid, and the allocated cellular channels are divided into sets assigned to columns of the grid. The allocated portion of the cellular spectrum is reused within each PCN subnetwork by assigning the same set to more than one of the columns so that different communications signals can be transferred over the same cellular channels.

1. Field of the Invention
The present invention relates to wireless communications networks, and, more particularly, to a personal communications network (PCN) and system architecture that enables integration of personal communications networks (PCN) and digital cellular networks (DCN).
2. Description of Related Art
A digital cellular network (DCN) is a mobile wireless telephone service in which radio coverage is divided into a network of cells and each cell is assigned a number of available radio frequencies. In the standard DCN, a base station transceiver system (BTS) transmits and receives control and voice communication information from a base station controller (BSC) within the same cell, and transfers the information to selected mobile users within the cell via a radio interface, such as, for example, the E-TDMA radio interface proposed by Hughes Network Systems, Inc. The base station controller (BSC) is controlled by a mobile switching center (MSC) that provides an interface to a public switched telephone network (PSTN) interface, and which provides mobility control across the cellular network. The mobile switching center (MSC) controls the transfer of communications information to selected base station controllers within the cellular network according to the position of the mobile user to whom the communications information is directed, to provide a roaming and handoff function between cells.
A personal communications network (PCN) is a mobile wireless telephone service for local use in environments in which the use of digital cellular communication is impracticable. Such environments include areas in which buildings or other structures cause undesirable signal transmission characteristics, or areas of high density telephony use. For example, a personal communications network may be configured as a private PCN (or radio PBX), to serve mobile users within an office building or plant, as a public PCN, for the high density telephony use areas, such as downtown areas, malls, and airports, or as a residential PCN where homes and condominiums are served by a local radio loop to outside base stations.
Numerous techniques have heretofore been proposed in the U.S. and Europe for the service of personal communications networks. These approaches typically involve a network of small cells which are served by a low-power radio interface. However, such systems generally require a radio interface different from that used in the digital cellular network. For example, personal communications systems are proposed that employ radio interfaces using Code Division Multiple Access (CDMA), while other systems (CT-2 and DECT) have adopted relatively wide band Time Division Multiple Access (TDMA) with Time Division Duplex (TDD) interfaces.
In addition, the allocation of frequency bands different from those committed to digital cellular communications has generally been required in such systems due to the scarcity of spectrum envisaged for PCNs sharing the cellular spectrum.
Thus, the basic disadvantages of the previously proposed PCN systems are that they require the use of different communications units for personal and cellular communications, different system infrastructures, and the allocation of different frequency bands.
Accordingly, from the user's perspective, it would be desirable to adapt PCN systems to cellular to eliminate the need for different communications units in different environments. For instance, cellular-based PCNs could enable the use of cellular portable units in the office, and new personal units could be made cellular-ready by car-based RF power boosters or by adherence to stringent distance limitations relative to the cellular base stations.
The major consideration in the adaptation of PCN to cellular to achieve the above advantages is the ability of the frequency spectrum currently allocated to cellular to support both cellular traffic and the multitude of localized high traffic densities usually associated with PCNs.

Integrated personal/cellular communications system architecture


A telephone line interface and associated circuitry that may be implemented to simultaneously couple DC loop voltage, ring bursts, and caller-ID data to the phone line side of a DAA circuit through a single two wire resistively coupled interface. The interface and circuitry may be implemented to combine processing of the DC loop voltage and ring bursts into a single circuit, with processing of caller-ID data being performed separately.

Electrical isolation barriers can be identified in many industrial, medical and communication applications where it is necessary to electrically isolate one section of electronic circuitry from another electronic section. In this context, isolation exists between two sections of electronic circuitry if a large magnitude voltage source (typically on the order of 1000 volts or more) connected between any two circuit nodes separated by the barrier causes less than a minimal amount of current flow (typically on the order of 10 milliamperes or less) through the voltage source. An electrical isolation barrier must exist, for example, in communication circuitry that connects directly to the standard two-wire public switched telephone network and that is powered through a standard residential wall outlet.
Direct Access Arrangement (DAA) circuitry may be used to terminate the telephone connections at a phone line user's end to provide a communication path for signals to and from the phone lines. DAA circuitry includes the necessary circuitry to terminate the telephone connections at the user's end and may include, for example, an isolation barrier, DC termination circuitry, AC termination circuitry, ring detection circuitry, and processing circuitry that provides a communication path for signals to and from the phone lines. It is also desirable that the DAA circuitry act as an isolation barrier to meet the requirements of FCC regulations, Part 68. Examples of DAA circuitry known in the art may be found described in U.S. Pat. No. 6,198,816, U.S. Pat. No. 6,298,133, U.S. Pat. No. 6,385,235 and in U.S. patent application Ser. No. 09/347,688 filed Jan. 2, 1999 and entitled "DIGITAL ACCESS ARRANGEMENT CIRCUITRY AND METHOD HAVING A SYNTHESIZED RINGER IMPEDANCE FOR CONNECTING TO PHONE LINES" by Tuttle et al., the disclosure of each being incorporated herein by reference.
In traditional DAA designs, a separate interface and circuit is typically required for each of loop voltage monitoring, ring burst detection and caller-ID demodulation. This is generally due to the significantly different voltage levels and frequencies involved in these signaling schemes. Furthermore, the ringer interface is often nonlinear which makes it unsuitable for measuring loop voltage or detecting caller-ID data. Implementing three interfaces requires numerous high voltage external components that increases both cost and board space usage. The separate circuits required also consume considerable power.
Loop voltage levels on the TIP and RING lines may be monitored for a number of reasons. For example, such levels may be utilized for on-hook or off-hook intrusion detection or determining other states of the phone line. Exemplary uses of DC loop voltage (also called DC line voltage) data may be seen in co-pending U.S. patent application Ser. No. 09/603,037, filed Jun. 26, 2000 and entitled "INTEGRATED MODEM AND LINE-ISOLATION CIRCUITRY AND ASSOCIATED METHOD HAVING INTRUSION DETECTION" by Timothy J. Dupuis, which is incorporated herein by reference.
In the past, a capacitive interface has been used to connect the ringer circuitry on the phone line side of the DAA directly to the TIP/RING Lines as described in U.S. Pat. No. 6,198,816. The capacitive interface linearly attenuates the TIP/RING signal voltage from high phone lines levels (typically 40–140 Vrms, 15–68 Hz) to levels within integrated circuit technology limitations. Because the interface provides a linear signal, it may also be connected to caller ID circuitry to demodulate caller ID data as described in U.S. Pat. No. 6,298,133, which has been incorporated herein by reference. The use of common inputs for the ringer circuitry and the caller-ID circuitry eliminates the need for a separate caller ID interface. However, the interface cannot pass DC signals, and a separate interface is required for loop voltage monitoring. This has typically been accomplished using a resistive interface connected to the hook switch circuitry.
An example of a prior art telephone system utilizing capacitive isolation barriers and configured for performing ring burst detection and caller-ID demodulation or analog to digital conversion is described below with reference to FIGS. 3 and 4. As illustrated, this system employs one interface for the separate ringer circuitry and the separate caller-ID circuitry. Not shown in FIGS. 3 and 4 is an additional interface and separate circuitry employed for loop voltage monitoring. Thus, in this prior art telephone system, two unique interfaces and three separate circuits are used to perform loop voltage monitoring, ring burst detection and caller-ID demodulation or analog to digital conversion.
As shown in FIG. 3, the TIP line 1602 and RING line 1604 are provided to the prior art communication system 110. The diode bridge 1606 receives the TIP line 1602 and RING line 1604 and provides an output to the external hookswitch devices 1702. A communication line 1705 couples the external hookswitch devices to the line side circuits 118. The line side circuits 118 are circuits isolated from external powers sources, such as power source 112, by an isolation barrier 120. The isolation barrier 120 may be a capacitive isolation barrier as previously described.
As shown in the prior art configuration of FIG. 3, phone line interface circuitry, such as a hookswitch, caller ID and ringer interface circuit 1704 is provided within the line side circuitry 118. The hookswitch, caller ID and ringer interface circuitry 1704 is coupled to the external hookswitch devices through line 1705 and ground through line 1707. The phone line loop current utilized by the line side circuits 118 is shown as Iloop. Circuitry 1704 is also coupled directly to the TIP line 1602 and the RING line 1604 through a capacitive interface 1703. The capacitive interface 1703 may be comprised of three high voltage (such as 300 V) capacitors 1703a, 1703b, and 1703c having capacitances of 2200 pF, 2200 pF and 5600 pF respectively, and linearly attenuates the TIP/RING signal voltage from high phone lines levels (typically 40–140 Vrms, 15–68 Hz) to levels within integrated circuit technology limitations. Bi-directional input/output lines 1706 are shown provided from the hookswitch, caller ID and ringer interface circuitry 1704 for communication through the isolation barrier 120 to the user powered circuits 116.
The user powered circuits 116 of prior art communication system 110 include ringer timing circuitry 1708. The ringer timing circuitry may bidirectionally communicate through line 1710 and the isolation barrier 120 to ringer circuits within the hookswitch, caller ID and ringer interface circuitry 1704 in the line side circuit 118. The ring detection output is provided on output line 1719 to a ring detection output pin 1720 of the user powered circuit 116. Alternatively, the ring detection output 1719 may be provided at the analog-to-digital converter ("ADC") data port pin 1718 by use of a mux 1716. Mux 1716 may be utilized to multiplex the ringer detection output 1719 and a signal line 1712 containing caller ID data from an ADC output from the line side circuit 118. The mux 1716 may operate in response to a caller ID field signal 1714 so that when caller ID information is present on the TIP and RING lines, caller ID information is presented at the ADC data port pin 1718 and when ringing information is present on the TIP and RING lines, ring detection information is presented at the ADC data port pin 1718. In this manner the ADC data port may reflect activity on the TIP/RING loop during ringing, caller ID fields, and off-hook operations.
FIG. 4 illustrates a more detailed view of some of the circuits of the hookswitch, caller ID and ringer interface circuitry 1704 of prior art communication system 110. As shown in FIG. 4, input line 1705 provides the TIP and RING signal information to integrated hookswitch circuits 1810. The integrated hookswitch circuits 1810 are those portions of the hookswitch circuitry integrated within the line side integrated circuit 118 (as opposed to portions of the hookswitch circuitry which may be off chip as designated by the external hookswitch devices 1702 as shown in FIG. 3). The ground line 1707 is also coupled to the integrated hookswitch circuits 1810. The TIP and RING information is also coupled into circuitry 1704 through a capacitive interface 1703. The TIP and RING information coupled through the capacitive interface 1703 may be provided to a ringer burst circuit 1802 and to a mux 1812. The mux 1812 operates in response to a control signal 1815. The control signal 1815 may be provided to indicate when caller ID information is present on the TIP and RING lines. Thus when caller ID information is present on the phone line, the caller ID information may be provided from the TIP and RING lines to an ADC 1814 for conversion to digital data which may then be transmitted across the isolation barrier 120. In other cases when caller ID information is not present (such as in an offhook situation), the mux 1812 may provide data from the integrated hookswitch circuits to the ADC 1814 for conversion to digital data which may then be transmitted across the isolation barrier 120. A power supply line 1816 may be provided to a variety of circuits such as the mux 1812 and the ADC 1814 from power obtained from the phone line through the hookswitch circuits. The power may be supplied even in conditions when the hookswitch is not normally closed (an on-hook condition). Bi-directional communication from the ringer burst circuit 1802 to the user powered circuit 116 may be provided on communication line 1817 through the isolation barrier as also discussed below in further detail.
As shown in FIG. 4, outputs 1703d and 1703e of the capacitive interface 1703 are coupled to ringer burst circuitry 1802 and are also connected to caller ID circuitry input lines 1804 and 1806 so that accurate caller ID data from the TIP/RING signals may be present on caller ID input lines 1804 and 1806, with the caller ID information being then provided from lines 1804 and 1806 to a mux 1812. In an alternate prior art configuration (not shown), a separate dedicated ADC may be coupled to capacitive interface outputs 1703d and 1703e for receiving, digitally converting and transmitting caller ID data across isolation barrier 120, i.e., rather than using ADC 1814 for this purpose. As further shown with respect to the prior art communication of FIGS. 3 and 4, loop current (Iloop) may be drawn from the TIP line 1602 and the RING line 1604 through interface lines 1705 and 1707, with virtually no (less than 10 uA) loop current being drawn during a ringing burst and only on-hook loop current being drawn during the caller ID field.
FIG. 5 illustrates an alternative prior art implementation of a combined ringer/caller-ID interface and associated circuitry 500 that may be implemented in a telephone system that employs two unique interfaces and three separate circuits to perform loop voltage monitoring, ring burst detection and caller-ID demodulation or analog to digital conversion. In FIG. 5, components to the left of the dotted line are off-chip and elements to the right are implemented on the line side chip of DAA circuitry. As illustrated, caller ID circuitry 510 and ringer circuitry 530 are coupled to the TIP and RING lines through a capacitive interface 550 that includes capacitors C1 (i.e., C1A, C1B) and C2. Capacitive interface 550 functions in a manner similar to capacitive interface 1703 of FIG. 4. The linear division factor is set by the ratio of C1 to C2 and is typically selected to insure that the DAA circuitry does not overload before the maximum ring threshold is exceeded. R1 determines the corner frequency of the highpass filter formed by R1, C1, and C2 and is typically selected such that the lowest frequency ring burst is passed without significant attenuation. R2 is utilized to protect the PAD diodes in the line side chip from excessive current during lightning strikes or other surges.
As illustrated in FIG. 5, one interface is shared between the ringer and caller-ID functions, however separate circuitry is used on chip. In this regard, the ringer circuit is a simple window comparator 530 that detects when the voltage on the line exceeds a certain preset positive or negative threshold thus causing ring detection signals RDTP or RDTN to go high, respectively. These signals are then sent across the isolation barrier of the DAA circuitry to circuitry within the system side chip that performs ring validation and generates timing signals indicating the location of caller-ID data between the first and second ring burst. As illustrated in FIG. 5, the much smaller magnitude caller-ID signals are converted to digital format in a 2nd order delta-sigma ADC 510 coupled to the interface through gain block 520. The resulting bit stream is sent across the isolation barrier to the system side chip for decimation or analog to digital conversion of the caller-ID data.
Still referring to the prior art implementation of FIG. 5, the placement of the more complex ring validation, timing, decimation, and caller-ID decoding circuitry on the system side chip results in lower power dissipation on the line side. This is desirable since it minimizes the circuitry on the line side chip, which decreases the amount of power that must be transmitted across the isolation barrier and minimizes the common-mode noise transmitted to the TIP/RING lines.
Although not shown in FIGS. 3–5, prior art loop voltage interface and circuitry have been implemented in such prior art systems using components both on and off the line side chip. In such prior art circuitry, the loop voltage is converted to digital format in a simple switched capacitor dual-slope counting ADC. The resulting PCM data is sent across the isolation barrier to the system side chip. Further details on such prior art loop voltage interface and circuitry may be found in co-pending U.S. patent application Ser. No. 09/603,037, filed Jun. 26, 2000 and entitled "INTEGRATED MODEM AND LINE-ISOLATION CIRCUITRY AND ASSOCIATED METHOD HAVING INTRUSION DETECTION" by Timothy J. Dupuis.
To summarize, in previous DAA implementations at least two unique interfaces and three separate circuits are required to simultaneously perform loop voltage monitoring, ring burst detection, and caller-ID demodulation. With regard to the combined ringer/caller-ID interface and circuitry shown in FIG. 5, three external capacitors and four external resistors are required. Furthermore, high voltage capacitors (e.g. 300 v) employed in the capacitive interface of prior art telephone communication systems are relatively expensive. In addition, large ring signals or a battery reversal can cause the protection diodes in the line side chip to turn on resulting in charge storage in the external capacitors. Once the protection diodes turn on the capacitive voltage divider ceases to operate linearly. Since caller-ID data should be processed within 100 msec of a battery reversal, some means must be provided to squelch or reset, the charge on these capacitors after an over voltage event. With regard to the loop voltage interface and circuitry of the prior art, the hookswitch must be off (i.e., telephone device on hook) in order to measure the loop voltage since the interface is shared with the hookswitch circuits.

Telephone line interface for DAA circuitry


A pulsed plasma accelerator includes two electrodes (1) arranged between dielectric bars (2) made from an ablating material, a discharge channel with an open end part whose walls are defined by the surfaces of electrodes (1) and dielectric bars (2), an energy accumulator (11) and current supplies (14,15) for connecting the electrodes (1) with the energy accumulator (11). The current supplies (14, 15) define in conjunction with the electrodes (1) and the energy accumulator (11) an external electric circuit, with characteristics of the external electric circuit being selected on the condition: 2≦C/L, where C (μF) is the electric capacitance of the external electric circuit, and L is the inductance of the external electric circuit, L≦100 nH. During operation of the plasma accelerator, quazi-nonperiodic pulse discharges are ignited and maintained in the discharge channel. By providing coordinated parameters of the external and internal circuits, a substantial increase in the efficiency of plasma acceleration is achieved.

It is customary to assume that plasma accelerators are apparatuses designed for ionization of a working substance accompanied by acceleration of an ionized gas (plasma) under the action of electromagnetic force and gas pressure force upon generation of an electric discharge.
Plasma acceleration occurs in plasma accelerators as a result of an electric breakdown in an electrode-to-electrode gap. In steady-state plasma accelerators, the electric discharge time is sufficiently long—the typical breakdown time t is at least 1 second. In pulsed plasma accelerators, the electric discharge is of shorter duration. The pulsed discharge time t is about 1-100 μs.
Pulsed plasma accelerators are currently employed as actuating systems in spacecraft control systems and as pulsed low-temperature plasma injectors.
It is common knowledge that in order to maintain a spacecraft in a desired orbital position during retarding in a relatively dense residual atmosphere of the outer space, it is advantageous to use small-sized propulsion units with low power consumption. Such requirements are satisfied with the use of propulsion units based on pulsed plasma accelerators. Most of such propulsion units use solid dielectric as a working substance releasing gaseous products as a result of ablation under the action of thermal and radiant energy of an electric discharge generated.
There is a great tendency nowadays to a wide employment in the outer space of low-orbiting (with orbit height Horb=400-1 000 km) light-weight and small-sized spacecrafts of relatively simplified construction and low cost, said spacecrafts having the typical weight in the range of from 50 kg to 500 kg. However, these light-weight and small-sized spacecrafts have substantially restricted power supplying capacities of electric propulsions providing high accuracy in keeping of orbital parameters of both individual spacecrafts and groups of such spacecrafts. For this purpose, highly efficient small-sized electric propulsions capable of correcting and stabilizing of spacecraft orbits at the minimal power consumption are demanded.
Steady-state plasma accelerators used as spacecraft controlling electric propulsions have a number of grave disadvantages including the complexity of plasma accelerator construction, the complexity of a manufacture process and operation of an accelerator, the increased manufacture and operating costs, as well as insufficient propulsive efficiency (plasma acceleration efficiency) and low performance reliability at the power consumption of less than 150 W.
An ablation pulsed plasma accelerator is the most promising propulsion for a spacecraft with regard to the simplicity of construction, reliability, low costs and proper functioning at the power consumption of from several watts to hundreds of watts. A pulsed plasma accelerator also provides for maximal accuracy of spacecraft control as compared to other kinds of propulsion units used as actuating systems. However, the efficiency of pulsed plasma accelerators of the prior art does not meet the operative requirements for handling the majority of spacecraft control problems.
A substantial increase in the operating efficiency of a pulsed plasma accelerator, primarily over the range of power consumption of from 20 W to 300 W, within which the basic problems for controlling of spacecraft orbital parameters are currently solved and will be solved in the near future, is of fundamental importance for widening the range of functioning of a spacecraft.
Presently the basic technical problems of a pulsed plasma accelerator are the excessive retardation of evaporation of a working substance with regard to a discharge current and, as a result, ineffective acceleration of a substantial part of plasma generated, which on the whole adversely affects the efficiency of accelerator (the efficiency of plasma acceleration).
It has already been pointed out in the very first studies on the investigation of plasma acceleration processes in a pulsed plasma accelerator (Artsymovitch L. A. et al, "Electrodynamic acceleration of plasma coagulates". ZHETF, Moscow, 1957, vol 33, No. 1) that the plasma acceleration efficiency is dependent upon dimensionless parameter q:q=l2C2U20/2mL0,                where l [H/m] is the linear inductance of accelerator electrodes;        C [F] is the capacity of an external discharge circuit;        U0 [V] is the initial voltage of an external discharge circuit;        m [kg] is the weight of a plasma coagulate;        L0 [H] is the initial inductance of an external discharge circuit.
The physical meaning of the parameter q lies in defining the ratio of a typical value of a magnetic pressure force to a typical value of an accelerated plasma coagulate inertia force. It has been established that an increase in the parameter q results in that a discharge approaches a nonperiodic shape with rising of plasma acceleration efficiency.
One of the known features of a pulsed plasma accelerator is that weight m of accelerated plasma is commonly proportional to the power Wo applied to the discharge:m≈kW0,                where W0=CU20/2;        k=10−8-10−9 kg/J is a proportionality factor.
When the dependence for W0 is introduced in the previous ratio, the dependence for the parameter q assumes the form of:q=12C2U20/2k(CU20/2)L0=(12/k)(C/L0).
So, with the assigned configuration and sizes of an accelerating channel of a pulsed plasma accelerator, the efficiency of plasma acceleration is characterized by the ratio of C/L0.
The specific technical solutions aimed at increasing the efficiency of plasma acceleration by means of a pulsed plasma accelerator and associated with the realization of theoretical reasoning of q of about C/Lo are not yet developed.
As an example, it is renowned a pulsed plasma accelerator designed for use as an electric propulsion of a system for controlling the position of a geostationary earth orbit satellite of a global communication system (A. I. Rudikov, N. N. Antropov, G. A. Popov. "Pulsed Plasma Thruster of Erosion Type for a Geostationary Artificial Earth Satellite", 44th Congress of the International Astronautical Federation, IAF-93-S.5.487, Graz, Austria: IAF, Oct. 16-22, 1993). Propulsive pulses generated by such a propulsion unit must neutralize the effects of outer factors upon a spacecraft in a geostationary orbit.
Each pulsed plasma accelerator incorporated in a propulsion unit of the prior art comprises electrodes (a cathode and an anode), one of the electrodes being made in the form of a copper rod and the other of the electrodes being made in the form of a plate, a solid dielectric working substance ablating under the action of an electric discharge, a system for supplying of a working substance into a rail-type discharge channel, and a discharge-initiating system. Power is supplied to accelerator electrodes via current supplies from an outer energy accumulator of 36 μF capacitance at the maximal voltage of about 3 kV.
Such an accelerator operates at a gas pressure less than 10-4 torr in an accelerating channel. The energy released with each pulse is about 160 J at the current pulse amplitude of 35 kA. The disadvantage of the given propulsion unit is low propulsive efficiency, which is less than 10%, owing to an oscillating nature of a discharge current variation during each pulse time.
In another pulsed plasma accelerator of the prior art (P. J. Turchi "Directions for Improving PPT Performance", 25th International Electric Propulsion Conference, IEPC 97-038, USA, Cleveland, Ohio: IEPC, Aug. 24-28, 1997), pulsed oscillating discharges were generated in a discharge channel with power being supplied to electrodes from a high-current capacitive accumulator. The stored energy of the accumulator was 20 J at an initiating voltage of 2 kV, and the accumulator capacitance was 10 μF. The inductance of an external electric circuit was 400 nH. However, despite the attempts of increasing the pulse time and creating a quasi-continuous discharge current at each pulse, the total propulsive efficiency of the propulsive unit did not reach 10%. The obtained propulsive efficiency does not allow such plasma accelerators to be employed in commercial spacecrafts.
With regard to the paper discussed, it should be mentioned that a proper conclusion was drawn on the need for coordination of impedances for internal and external circuits in a pulsed plasma accelerator. However, quite complicated and low-effective solutions are offered for handling the given problem, said solutions including the incorporation of additional components in the electric circuit. The mentioned components, such as capacitors, inductance coils and commutators, allow the internal and external circuits to be coordinated and a quasi-nonperiodic discharge in a pulsed plasma accelerator to be obtained, though the positive effect is substantially reduced by power losses associated with such components.
Apart from the above-mentioned, there exists other viewpoint concerning with an increase in the efficiency of a pulsed plasma accelerator. As an example, a pulsed plasma accelerator (propulsion) is known which comprises an accelerating channel defined by two electrodes, an insulator adapted for separating these electrodes and serving as a working substance, a discharge-initiating system, and an energy accumulator based on high-current capacitors and connected to the electrodes by means of a current supply. The given propulsion uses teflon as a working substance (Gregory G. Spanjers et al. "Investigation of Propellant Inefficiencies in a Pulsed Plasma Thruster", AiAA-96-2723, 32nd JPC, Lake Buena Vista, Fla., USA: AIAA/ASME/SAE/ASEE, Jul. 1-3, 1996). During operation of the propulsion, the influence of electric discharge energy upon the efficiency of use of a working substance was investigated. However, despite the resultant increase in a propulsive pulse and propulsion value, the total propulsive efficiency of the plasma accelerator at the discharge energy of about 40 J varied from 7% to 8%. The relatively low propulsive efficiency was due to the oscillating nature of the discharge current variation during each pulse.
The conclusion was drawn in the discussed paper that in order to increase an efficiency of a pulsed plasma accelerator, the first one half-period time of a discharge current must be reduced and its amplitude must be increased. The above conclusion was supported by reliable experimental results, however it did not take into account nonlinearity of processes occurred in the input electric circuit of the pulsed plasma accelerator and caused by plasma.
In order to increase propulsive characteristics of pulsed plasma accelerators (propulsions), accelerators were designed for high level of electric discharge energy (W. J. Guman and D. J. Palumbo "Pulsed Plasma Propulsion System for North-South Stationkeeping", AIAA-76-999, AIAA International Propulsion Conference, Key Biscayne, Fla., USA: AIAA, Nov. 14-17, 1976). A known pulsed accelerator (propulsion) includes two electrodes defining an accelerating channel, dielectric bars made from teflon and arranged between the electrodes, a ceramic end insulator, and a capacitive accumulator. The capacitance of the accumulator was rated for the generation of an electric discharge of about 750 J in the accelerating channel.
The discharge generated in the discharge channel of the present plasma accelerator is of oscillating type. The maximal total propulsive efficiency of the propulsion at the discharge voltage of 2.5 kW was 25.6%. However, with the indicated level of discharge energy the propulsive efficiency of the plasma propulsion may not be accepted sufficient since the efficiency of competitive plasma (magnetic plasma) propulsions, such as steady-state plasma propulsions, is up to 45% at this energy level.
It is known a pulsed plasma accelerator (propulsion) comprising two flat copper electrodes, two dielectric bars manufactured from an ablating material and arranged between the said electrodes, a discharge-initiating device, and an energy accumulator (N. Antropov et al. "Parameters of Plasmoids injected by PPT", AIAA 97-2921, 33rd AIAA/ASME/SAE/ASEE Joint Propulsion Conference, Seattle, Wash., USA: AIAA/ASME/SAE/ASEE, Jul. 6-9, 1997). An accelerating channel of the plasma accelerator is defined by surfaces of the electrodes and side surfaces of the dielectric bars. The energy accumulator includes five high-current capacitors with the total stored energy of 80-100 J. The operating voltage of the capacitor battery is 2.5-2.8 kV. The inductance of an external electric circuit connected to the electrodes of accelerator was 20 nH. The efficiency of plasma accelerator did not exceed 13% with the energy of electric discharge of 100 J.
The closest analog of the claimed invention is an erosion (ablation) plasma propulsion (accelerator) disclosed in Pat. No RU 2143586 C1 (IPC-6 F03H1/00, H05H1/54, published 27 Dec. 1999). The known analog includes electrodes (a cathode and an anode), which are connected via an ohmic and inductance load to a capacitor (energy accumulator) plates, a ceramic end insulator, which separates the electrodes from one another, and dielectric bars made from ablating material and arranged between the electrodes. The energy accumulator is connected to the electrodes through thin copper busbars (current supplies). The discharge channel walls are defined by the surfaces of electrodes and dielectric bars. The electrodes of the known plasma accelerator are made in the form of plates. A discharge-initiating device (igniter) is located in a slot formed in the end insulator.
The dielectric bars used in the known plasma accelerator are movable toward a discharge channel midline by means of a special moving device (a spring pusher). The dielectric bars are caused to move until abutment against a stop made in the form of a step on the surface of electrode.
Plasma is accelerated in the discharge channel of the plasma accelerator in the following manner. A narrow high-voltage pulse is supplied from a discharge-initiating unit to the electrodes of the discharge-initiating device. A surface breakdown results in generating of a plasma coagulate, which causes short-circuiting of the electrodes in the slot of the end insulator where an electric arc discharge is created. During breakdown, electrodes are at a "waiting" potential. A working substance is evaporated from the surfaces of the dielectric bars by radiant discharge energy, ionized and accelerated by electromagnetic force and gas dynamic pressure.
During operation of a plasma accelerator—analog, cord-shaped stable plasma is generated at the leading end of the accelerating channel to inhibit deposition of a carbon film in this part of the channel and, accordingly, eliminate non-uniform consumption of the working surface of dielectric bars. This phenomenon enhances the stable propulsive characteristics of the accelerator due to the uniform evaporation of the working substance.
The electric discharge in the accelerating channel of the plasma accelerator is of oscillating nature, with the number of one-half periods of pulse discharge current variations being three. As a result, the maximal propulsive efficiency of the plasma accelerator does not exceed 14%.
With the known ablation pulsed plasma accelerator, one of the greatest problems immediately affecting the efficiency characteristics of the accelerator are the working substance losses occurring in the accelerating channel during the plasma acceleration process.
The reason for the working substance losses has to do with space and time discrepancies of the two processes occurring in the accelerating channel of the pulsed plasma accelerator:                a relatively fast process (tpr of about 1.5-3 μs) of formation and acceleration of a discharge current region (a current arc);        a relatively slow process of heating the working surfaces of the working substance bars, ionization of the working substance, generation of a plasma flow and acceleration thereof (tpr is about 7-12 μs).
The total oscillatory electric discharge time of the known pulsed plasma accelerator-analog is 8-15 μs depending on the sizes of the accelerating channel and the features of the discharge circuit. However, as it had been established, an effective electromagnetic process for plasma acceleration occurred only during the first discharge of the accumulator (the first one-half period of the discharge current), with the time of the said discharge making from 1.5 to 3.0 μs depending on the energy and sizes of the accelerator. Furthermore, in the course of the discharge process, only the ablation (evaporation) of the working substance and thermal (gas dynamic) plasma acceleration had occurred.

Gosudarstvennoe Nauchnoe Uchrezhdenic “Gosudarstvenny Nauchno-Issledovatelsky Institut Prikladnoi Mechanik I Elektrodinamiki”


A continuous shear deformation apparatus comprises: a roller for pushing a metal sheet to be processed into dies; the dies having an inlet for introducing a metal sheet, a shear deformation zone for shear-deforming the sheet, and an exit; and a control unit for controlling a gap of the dies exit depending on the compressive stress generated at the metal sheet while the metal sheet passes through the shear deformation zone of the dies. The compressive stress generated at the metal sheet becomes constant when the metal sheet is shear-deformed, and thereby the thickness of the metal sheet is uniformly controlled in a longitudinal direction.

1. Field of the Invention
The present invention relates to a continuous shearing apparatus controlling a thickness uniformity of a metal sheet, and more particularly, to a continuous shearing apparatus preventing a thickness of a sheet from being increased during the process, decreasing a thickness deviation of the sheet in a longitudinal direction, and performing a continuous shearing for a long sheet such as a coil.
2. Description of the Conventional Art
A continuous shearing apparatus as shown in FIG. 1, called as an equal channel angular rolling (ECAR) apparatus, includes a rolling device for supplying a metal sheet 20 to dies and deformation dies with an L-shaped passage causing shear deformation when a metal sheet is passing there through. The rolling device is composed of two rollers 10a and 10b, and the dies are composed of an upper die 30a and a lower die 30b. Screws 40a and 40b for controlling the gap of the dies are provided at a dies fixing wall 50.
A metal sheet 20 through the rollers 10a and 10b passes an inlet passage between A and B and is pushed to an exit (a passage after B), and the metal sheet receives shear-deformation. As the result of the shear deformation, the microstructure of the sheet becomes grain-refined so that the shear deformed sheet may have improved mechanical properties such as high strength, formability, etc.
However, in the conventional continuous shearing apparatus, when a sheet 20 goes from the rollers 10a, 10b to the shear deformation zone (B), compressive stress is generated by deformation resistance at the shear deformation zone. Such a compressive stress increases the thickness of the sheet which goes into the shear deformation zone. When the thickened sheet passes through the shear deformation zone, a larger resistance is caused thereby to increase the sheet thickness much more. Thus, as the shear deformation process continues, the sheet gets thicker. When the thickness of the sheet exceeds a limited gap of the dies exit (after B), the shear deformation processing cannot be performed any longer. Consequently, the conventional apparatus is not appropriate to the continuous processing for long sheets, such as coils.

Continuous shear-deformation apparatus for controlling thickness uniformity of a metal sheet

Korea Institute of Science and Technology


A polypropylene for an electric material has a melt flow rate of 0.1 to 30 g/10 min., a mesopentad fraction calculated from a 13C-NMR spectrum of 0.90 to 0.99, and a firing residue of 50 ppm by weight or less based on the polypropylene, a titanium content and an iron content which are detected from the firing residue, of 1 ppm by weight or less and 0.1 ppm or less, respectively, based on the polypropylene, and the chlorine content of 5 ppm by weight or less based on the polypropylene. The above polypropylene exhibits excellent electric insulation and has a roughened surface when it is formed into a film, and thus the polypropylene can be suitably used for a capacitor film without using an additive such as a β crystal nucleating agent. The polypropylene is also useful as a material of a film for coating an electric wire and a material for an instrument for conveying an electronic material.

Polypropylene has been utilized in diverse states for a wide range of raw materials for electric appliances owing to its excellent electrical insulation characteristics. For example, high-purity polypropylene which is extremely reduced in impurities caused by a catalyst is made into a film as thin as 20 μm or less and, in recent years, 5 μm or less, and is applied to a high-performance condenser (for example, Japanese Patent Application Laid-Open (JP-A) No. 6-236709).
However, it is difficult to say that the electrical insulation characteristics of polypropylene currently used are universal in all applications, and if a polypropylene having higher insulation characteristics can be stably provided, it is industrially very useful. As a method for solving this problem, earnest studies have been made to provide a highly purified polypropylene, for example, by using a method where remaining catalyst residue and chlorine content is reduced as much as possible, as disclosed in publications of JP-A Nos. 62-113548 and 2-150443. The present inventors also recognize that the insulation characteristics of polypropylene are significantly improved by these methods. At the same time, the present inventors also recognize that such polypropylene obtained in these methods does not necessarily provide a fixed level of electric insulation characteristics well reproducibly. Namely, the electric insulation characteristics sometimes vary largely between lots and the electric insulation characteristics sometimes vary depending on the position of sampling even if polypropylene materials obtained in the same lot are molded to produce electric materials. It is reasonable that in the case of continuously producing molded products for electric material from polypropylene in an industrial scale, a limitation is placed upon the frequency of pre-quality control of raw material polypropylene from the viewpoint of production speed and production cost. Therefore, if a maximum amount of polypropylene for electric materials can be obtained stably by making pre-quality checks in the smallest frequency, it can be said that this gives very enormous contribution to the development of polypropylene industries.

Polypropylene and application of said polypropylene to electric material


A method of forming a transistor device includes providing a drift layer having a first conductivity type and an upper surface, forming first regions in the drift layer and adjacent the upper surface, the first regions having a second conductivity type that is opposite the first conductivity type and being spaced apart from one another, forming a body layer on the drift layer including the source regions, forming spaced apart source regions in the body layer above respective ones of the first regions, forming a vertical conduction region in the body layer between the source regions, the vertical conduction region having the first conductivity type and defining channel regions in the body layer between the vertical conduction region and respective ones of the source regions, forming a gate insulator on the body layer, and forming a gate contact on the gate insulator.

Power semiconductor devices are widely used to regulate large current, high voltage, and/or high frequency signals. Modern power devices are generally fabricated from monocrystalline silicon semiconductor material. One widely used power device is the power Metal Oxide Semiconductor Field Effect Transistor (MOSFET). In a power MOSFET, a control signal is supplied to a gate electrode that is separated from the semiconductor surface by an intervening silicon dioxide insulator. Current conduction occurs via transport of majority carriers, without the presence of minority carrier injection that is used in bipolar transistor operation.
MOSFETS can be formed on a silicon carbide (SiC) layer. Silicon carbide (SiC) has a combination of electrical and physical properties that make it attractive as a semiconductor material for high temperature, high voltage, high frequency and/or high power electronic circuits. These properties include a 3.2 eV bandgap, a 4 MV/cm electric field breakdown, a 4.9 W/cm-K thermal conductivity, and a 2.0×107 cm/s electron drift velocity.
Consequently, these properties may allow silicon carbide-based MOSFET power devices to operate at higher temperatures, higher power levels, higher frequencies (e.g., radio, S band, X band), and/or with lower specific on-resistance and/or higher blocking voltages than silicon-based MOSFET power devices. A power MOSFET fabricated in silicon carbide is described in U.S. Pat. No. 5,506,421 to Palmour entitled "Power MOSFET in Silicon Carbide" and assigned to the assignee of the present invention.
Although silicon carbide is theoretically capable of sustaining high reverse voltages, it may be desirable to shield certain portions or features of a silicon carbide device, such as the gate insulator, the device edge, etc., from high electric fields, as breakdown may be more likely to occur at these locations.

Field effect transistor devices with buried well regions and epitaxial layers


An aircraft having a fuselage and a front landing gear; both sides of the rear bottom of the fuselage are fixedly connected with the rear landing gear; one end of the front landing gear is rotatably connected to the front bottom of the fuselage. When the front landing gear rotates to the first position, the second position and the third position, the connecting line between the end of the front landing gear away from the fuselage and the end of the rear landing gear away from the fuselage intersects with the plane, where the fuselage is located, on the side close to the front of the fuselage, parallel to and intersect on the side close to the rear of the fuselage.

When the existing small aircraft is not working, the plane where the fuselage is located is parallel to the ground, and because the small aircraft is relatively low and small, the users often need to stoop to avoid the canard wing in front of the fuselage when entering and leaving the cabin at the bottom of the fuselage, which causes inconvenience to the users. At the same time, the above problems also affect the access efficiency of the users and cause hidden dangers in safety.


A device for coupling a coolant duct of a rotating part, especially for a back-up or transport rollers, includes a hollow resilient compensator device fixedly connected to a journal of the rotating part, wherein the journal comprises a bore hole for conducting a coolant and is insertable in a bearing of a stationary part. A second end of the compensator is connected to a first sealing ring. The compensator is enclosed by a receptacle sleeve which includes a second sealing ring that creates a sealin contact with the first sealing ring. The receptacle is connected to the stationary part at an adjustable distance wherein a pretensioning exerted on the compensator by the receptacle sleeve via the first and second sealing rings is adjustable in response to a distance of the receptacle sleeve from the stationary part.

1. Field of the Invention
The invention relates is directed to a device for coupling the coolant duct of a rotating part.
2. Description of the Prior Art
Reference DE-PS 42 07 042 discloses a generic device for coupling the coolant duct of a back-up and transporting roll. This device is supported by pins in bearing blocks or pillow blocks by roller bearings, and coolant flows through the device along an axial bore hole that is guided through the pins. Every bearing block is closed by a cover. The cover has a cooling duct which is connected at one end to a coolant inlet and coolant outlet, respectively. The other end opens into the region of the pin bore hole. A compensator is arranged between the duct opening of the cover and the bore hole of the roll and cooperates with a seal which coaxially contacts a sealing face arranged relative to the roll shaft. The seal is preferably constructed as a lip seal.
It is disadvantageous in this construction that the sealing lip of the sealing ring is subject to wear because of the movement occurring on it and therefore has a limited life. Further, the attainable temperature range is limited because lip sealing rings are usually made from elastomers. Moreover, the compensator cannot be pretensioned in a deliberate manner, so that it is not possible to adapt to different internal pressures of the coolant.

Device for coupling a coolant duct of a rotating part


A wireless network system arranges a plurality of access points along the aisles in a vehicle having two or more aisles. The positions of the access points on the first aisle and the positions of the access points on the second aisle are arranged in a zigzag pattern. The distance between neighboring access points is thus great, and there is no signal interference between adjacent access points.

1. Field of Technology
The present invention relates to a wireless network system having access points or base stations at least capable of wireless transmission and terminals at least capable of wireless reception in a vehicle having a plurality of aisles.
2. Description of Related Art
Constructing a system connecting a plurality of terminals to a network in a building or vehicle has typically involved laying at least as many wired conductors as terminals.
While this method offers the advantage of highly reliable communication, the time and cost required to lay the lines and the work involved in subsequent maintenance are significant drawbacks.
Networks that connect wirelessly to the terminals are now available and are increasingly common. Wireless networks offer the advantage of requiring less time for installation and maintenance than conventional wired networks, and are therefore also less expensive. Wireless networks also eliminate the weight of the wires and the space needed to lay the wires, and are therefore particularly advantageous when installed in transportation vehicles.
Reflection of the radio waves by obstacles produces a phase shift in the signal waves that results in fading because the phase-shifted signals are then merged and result in a weakened reception level. Fading causes a loss of reception packets (errors), and narrows the usable bandwidth.
The literature is also silent on how the access points should be located in a vehicle having multiple aisles.
The general positioning of access points is described in Japanese Unexamined Patent Appl. Pub. H8-321799, Japanese Unexamined Patent Appl. Pub. H11-127096, and Japanese Unexamined Patent Appl. Pub. 2000-13853, but these documents are silent on the location of access points in a vehicle.
The access points could be located at equidistant intervals from the front to the back inside the passenger cabin.
However, if the signal strength of the wireless signals output from the access points is increased so that the signals can reach both ends of the vehicle, the wireless signals from two adjacent access points located one behind the other will interfere with each other, and signal quality will drop.

Wireless network located within a vehicle containing access points and terminals for wireless communication


A connector includes a housing having a mating end, a wire receiving end and a longitudinal axis therethrough. The housing holds a plurality of contacts grouped in pairs and arranged about the axis. At least one shielding member is located within the housing. The at least one shielding member isolates each contact pair from an adjacent contact pair. An organizer is configured for attachment to the wire receiving end of the housing. The organizer defines a central opening that receives a plurality of signal wires. The organizer includes a plurality of wire guides arranged about the central opening. Each wire guide receives one of the signal wires.

The invention relates generally to electrical connectors, and more particularly, to a connector that minimizes crosstalk among signal conductors in the connector, minimizes return loss in a pair of signal conductors in the connector, and minimizes alien cross talk from signal conductors in neighboring connectors.
In electrical systems, there is increasing concern for preserving signal integrity as signal speed and bandwidth increase. One source of signal degradation is crosstalk between multiple signal paths. In the case of an electrical connector carrying multiple signals, crosstalk occurs when signals conducted over a first signal path are partly transferred by inductive or capacitive coupling into a second signal path. The transferred signals produce crosstalk in the second path that degrades the signal routed over the second path.
For example, a typical industry standard type RJ-45 communication connector includes four pairs of conductors defining different signal paths. The RJ-45 plug design is dictated by industry standards and is inherently susceptible to crosstalk. In conventional RJ-45 plug and jack connectors, all four pairs of conductors extend closely parallel to one another over a length of the connector body. One pair of conductors is also split around another conductor pair. Thus, signal crosstalk may be induced between and among different pairs of connector conductors. The amplitude of the crosstalk, or the degree of signal degradation, generally increases as the frequency increases. More crosstalk can be created by the contacts in the jack that interface with the contacts in the plug. As signal speed and density increase, alien crosstalk, or crosstalk between neighboring connectors must also be addressed in preserving signal integrity.
At least some RJ-45 jacks include features that are intended to suppress or compensate for crosstalk. The shortcomings that are inherent in jacks such as the RJ-45 can be expected to become more serious as system demands continue to increase. It would be desirable to develop a connector that is designed to minimize both internal crosstalk and alien crosstalk at the outset rather than to correct for crosstalk after the fact.
Another source of signal degradation is return loss resulting from signal reflections along the conductors. Return loss can originate from multiple sources such as variations in impedance among the various elements in the connector as well as along the signal path. Improving return loss performance has proven to be difficult.

Electrical connector with enhanced jack interface


The invention involves encapsulation of phosphorescent molecules in polymeric matrices to prevent phosphorescence quenching. Specifically, polymers containing a significant portion of halogens have been found to be good matrices for encapsulation of phosphorescent molecules to provide strong phosphorescence at ambient conditions. Those encapsulated phosphorescent molecules can find a wide variety of applications for detection of many species, including biological and chemical molecules as well as micro-organisms.

Phosphorescence is the result of a three-stage process. In the first stage, energy is supplied by an external source, such as an incandescent lamp or a laser, and absorbed by the phosphorescent compound, creating excited electronic triplet states (as opposed to fluorescence, which only has a singlet excited state). In the second stage, the excited states exist for a finite time during which the phosphorescent compound undergoes conformational changes and is also subject to a multitude of possible interactions with its molecular environment. During this time, the energy of the excited states is partially dissipated, yielding relaxed states from which phosphorescence emission originates. The third stage is the phosphorescence emission stage in which energy is emitted, returning the phosphorescence compound to its ground states. The emitted energy is lower than its excitation energy (light or laser) and thus of a longer wavelength. This shift or difference in energy or wavelength allows the emission energy to be detected and isolated from the excitation energy.
Quenching of phosphorescence is a phenomenon in which various reactants will bond with the triplet states and decrease the effective amount of phosphorescent compound available for use, thus interrupting the phosphorescent signal. Oxygen and water are strong quenchers of triplet states and may cause decay of the phosphorescence signal, thereby limiting its use in applications such as, for example, most practical biological assay applications. In order to obtain strong phosphorescence, oxygen often must be removed during the phosphorescence measurement.
Several phosphorescence molecules have nonetheless been documented for application in biological assays, including metallo-porphyrins. The phosphorescence molecules for biological assays are usually water soluble and have functional groups for easy covalent conjugation with biological molecules such as proteins. During use of these compounds, oxygen can be removed by various means, including using Na2SO4 in an aqueous solution. Unfortunately, these means are often cumbersome to use and generate problems in obtaining consistent results.
One way to avoid oxygen quenching of the phosphorescence is to encapsulate phosphorescent molecules inside a solid matrix to shield them from quenchers such as oxygen and water molecules. Selection of the encapsulation matrix is important. The matrix should have relatively low oxygen permeability and have relatively high solubility of the phosphorescent molecules so that high loading of the phosphorescent molecules can be achieved and strong phosphorescence can be obtained. For many applications, mono-dispersed phosphorescent particles of different sizes are desired. In those cases, the matrices should be capable of forming mono-dispersed particles. For other applications, the phosphorescent particles may also be desired to have various surface functional groups to allow further surface modifications.
Different types of matrices have been used for encapsulation of phosphorescent molecules to form phosphorescent particles. These matrices include inorganic materials and polymers. Of the polymers used for encapsulation of phosphorescent molecules to form particles, polystyrene (PS) and polyacrylonitrile (PAN) and their derivatives have been commercially used. These polymeric systems, however, do not allow for maximal phosphorescence intensity at ambient conditions. The polystyrene matrix is not ideal for encapsulation of phosphorescent molecules because of the poor solubility of many phosphorescent molecules (sometimes referred to as "phosphorescent dye" or "dye") in polystyrene, which results in low dye loading and relatively low phosphorescence. The oxygen solubility of polystyrene is also believed to be relatively high. PAN and its derivatives have been found to have low oxygen permeability but they have limited solubility for many phosphorescent molecules as well, which also limits their application for encapsulation of those phosphorescent molecules. There is a need for new matrix systems for the encapsulation of phosphorescent molecules to provide even higher phosphorescence intensity than that provided by PAN and its derivatives.

This patent is subject to a terminal disclaimer.

Polymeric matrices for the encapsulation of phosphorescent molecules for analytical applications


The solar charger is provided with a case 1 that can hold a rechargeable battery 5 in a removable fashion, and a solar cell 4 to supply charging power to the rechargeable battery 5 loaded in the case 1. The case 1 is formed in a shape having a bottom surface 2 and at least two tapered surfaces 3 with different slope angles α with respect to the bottom surface 2, and the solar cell is disposed on the bottom surface 2. The angle of inclination θ of the solar cell 4 provided on the bottom surface 2 of the solar charger is changed by disposing a tapered surface 3 having a different slope angle α on a flat surface.

1. Field of the Invention
This invention relates to a solar charger that charges a rechargeable battery via a solar cell, and in particular relates to a solar charger that can efficiently charge a rechargeable battery over the four seasons of the year.
2. Description of the Related Art
Solar cells produce electricity most efficiently when oriented perpendicular to the sun's rays. This is because solar energy is most efficiently transferred to solar cells irradiated in this orientation. The sun's rays irradiate solar cells with energy of approximately 1 KW per square meter. Consequently, solar cells with an energy conversion efficiency of 10% generate 100 W of electricity per square meter. However, if the solar cells are inclined at an angle of 45° with respect to the sun's rays, solar energy supplied to the solar cells drops by 30%. If the solar cells are further inclined to an angle of 60°, solar energy supplied to the solar cells drops to one half. This shows how important orienting solar cells perpendicular the sun's rays is for efficiently charging rechargeable batteries via solar cells.
To efficiently charge rechargeable batteries via solar cells, the present applicant developed a solar charger that can change the angle of inclination of the solar cells (refer to Japanese Patent Application Disclosure SHO 63-19770[1988]).


The device includes an incremental optical encoder (3) comprising two parts, 4,5) which are displaceable in rotation within one another. One part (5) is associated with a movable component (1) and the other part (4) with a fixed component (2) and its output is connected to a device for determining the angular position of the movable component (1) relative to the fixed component (2) on the basis of the relative angular positions of the two encoder parts. The encoder (3) is carried by one of the components (1), and one if its parts (5) is connected to this component (1) while the other part (4) is connected to an optical device for slaving the encoder part in at least one specified orientation in relation to the other component (2).

In certain machines such as, astronomical apparatuses and more particularly telescopes, it is important to be able to measure in an extremely precise manner the angular position of a component which is displaceable in rotation in relation to a fixed component.
This is so, for example, in the case of a telescope mounting which is displaceable in rotation within a supporting structure for the same and more particularly where it is desired to measure the azimuth angle or the elevation angle of this mounting.
In fact, these measurements must be made in an extremely precise manner with a very high resolution.
In the prior art, a certain number of devices are already known which permit the measurement of the angular position of a component which is movable in relation to a fixed component.
Thus, for example, it is possible to make use of an incremental optical encoder in the extension of the movable component, one of the parts of this encoder being fixed and being connected to the fixed component, while the other part is mounted so as to be displaceable in rotation within the fixed part and is connected to the movable component.
The output of this encoder is connected to means for determining the angular position of the movable component in relation to the fixed component on the basis of the relative angular position of the two encoder parts.
Any coupling means may be employed to connect the movable part of the encoder and the movable component of which it is necessary to measure the angular position in relation to the fixed component.
The structure of these coupling means must comply with a certain number of requirements in order not to disturb the measurement, while accepting certain defects of coaxiality between the components, these defects being due, for example, to the imperfect nature of the supporting bearings for the movable component. This leads to the construction of coupling means which are extremely complex and costly and which are relatively difficult to implement and maintain.
Furthermore, it is not always easy to have direct access to the end of the movable component in order to connect this end to the movable part of the encoder.
In order to solve the latter problem, use has been made of other devices comprising an encoded strip fixed, for example, to the periphery of the movable component. This strip is associated with any reading means which are disposed facing this strip, for example on the fixed component, and the output of which is connected to the means for determining the angular position of the movable component in relation to the fixed component.
However, the precision of these devices is dependent on the size of the assembly.
Furthermore, these devices are extremely sensitive to the clearances for mounting of the movable component within the fixed component, to thermal expansions or to the mechanical stresses to which these two components are subjected, so that in order to obtain an acceptable precision it is necessary to multiply the reading means at the periphery of the strip and to undertake comparisons and an in situ calibration of these devices in relation to a conventional standardization incremental optical encoder.
The validation of these calibrations requires a fidelity of the observed phenomena; in certain applications, this is impossible to obtain, so that the desired precision cannot always be obtained with these devices.

Device for measuring the angular position of a component which is rotatably displaceable relative to a fixed component, especially of a telescope mounting in relation to its supporting structure


A wire guide device of a wire electrical discharge machine includes a first roller shaft, a first wire guide roller provided at an end of the first roller shaft, a second roller shaft, and a second wire guide roller provided at an end of the second roller shaft and having an end face in an axial direction provided to face an end face of the first wire guide roller in the axial direction. The first wire guide roller and the second wire guide roller have a conical surface and a conical surface with which a wire electrode is in contact.

A wire electrical discharge machine includes a feed roller for sending out a new wire electrode and a wire electrode collection roller for collecting a used wire electrode. When a wire electrode is fed from the feed roller to the wire electrode collection roller, the wire electrical discharge machine applies a constant inter-electrode voltage between the wire electrode and a workpiece, which are used as electrodes, thereby producing electrical discharges between the electrodes to machine the workpiece into a desired shape while relatively moving the wire electrode and the workpiece with the wire electrode being tensioned.
In an early stage of electrical discharge machining, rough machining is performed. Rough machining is machining to cut a machining allowance as much as possible in one-time machining to cut out to a rough shape. A wire electrode with a diameter of 0.35 mm to 0.10 mm is used in rough machining, and the wire electrical discharge machine controls the tension of the wire electrode, the feed speed, and the amount of current supplied for electrical discharge machining during the rough machining. This allows continuous machining without a break in the wire electrode. In a final stage of the electrical discharge machining, finish machining is performed. In finish machining, in which the amount of machining of a workpiece is smaller than that in rough machining, the remainder on a machined surface after rough machining can be cut to improve surface accuracy, or a corner radius (R) of a workpiece can be minimized. The corner R means roundness at a corner of the workpiece. As a wire electrode at the time of finish machining, an ultrafine wire electrode with a diameter of 0.03 mm to 0.01 mm smaller than the diameter of the wire electrode used for rough machining is used.
The wire electrical discharge machine ordinarily uses a set of reference dies called diamond dies that are disposed immediately above and below a workpiece. Each diamond die has a hole with a slight clearance with respect to the diameter of a wire electrode. Therefore, when the wire electrode is changed for a change from rough machining to finish machining, or when the wire electrode is changed for a change from finish machining to rough machining, a change between diamond dies having a hole appropriate to the wire electrode used for rough machining and diamond dies having a hole appropriate to the wire electrode used for finish machining is required. In other words, the wire electrical discharge machine cannot perform machining continuously from rough machining to finish machining without changing the diamond dies provided in a wire electrode feed mechanism, or without adjusting a reference position in which the wire electrode is fed.
Patent Literature 1 discloses a technique for stabilizing wire feed using a mechanism other than diamond dies. In Patent Literature 1, the outer peripheral surface of each of two guide rollers is provided with a circumferential groove that is an annular groove portion continuing in the rotational direction of the guide roller, and the two guide rollers provided with the circumferential grooves are in contact with each other at their outer peripheral surfaces so that their circumferential grooves are opposed to each other. A wire electrode is passed through a circular space formed by each other's circumferential grooves in contact. The conventional art disclosed in Patent Literature 1 is directed to a structure in which the feed speed of the wire electrode and the rotational speed of the guide roller are matched with each other to stably feed the wire electrode.

Wire guide device of wire electrical discharge machine and wire electrical discharge machine