A memory system architecture/interconnect topology that includes at least one point-to-point link between a master, and at least one memory subsystem. The memory subsystem includes a buffer device coupled to a plurality of memory devices. The memory system may be upgraded through dedicated point-to-point links and corresponding memory subsystems. The master communicates to the plurality of memory devices in each memory subsystem through the respective buffer device via each point-to-point link.

This invention relates to memory systems, memory subsystems, memory modules or a system having memory devices. More specifically, this invention is directed toward memory system architectures which may include integrated circuit devices such as one or more controllers and a plurality of memory devices.
Some contemporary memory system architectures may demonstrate tradeoffs between cost, performance and the ability to upgrade, for example; the total memory capacity of the system. Memory capacity is commonly upgraded via memory modules or cards featuring a connector/socket interface. Often these memory modules are connected to a bus disposed on a backplane to utilize system resources efficiently. System resources include integrated circuit die area, package pins, signal line traces, connectors, backplane board area, just to name a few. In addition to upgradeability, many of these contemporary memory systems also require high throughput for bandwidth intensive applications, such as graphics.
With reference to FIG. 1, a representational block diagram of a conventional memory system employing memory modules is illustrated. Memory system 100 includes memory controller 110 and modules 120a-120c. Memory controller 110 is coupled to modules 120a-120c via control/address bus 130, data bus 140, and corresponding module control lines 150a-150c. Control/address bus 130 typically comprises a plurality of address lines and control signals (e.g., RAS, CAS and WE).
The address lines and control signals of control/address bus 130 are bussed and xe2x80x9csharedxe2x80x9d between each of modules 120a-120c to provide row/column addressing and read/write, precharge, refresh commands, etc., to memory devices on a selected one of modules 120a-120c. Individual module control lines 150a-150c are typically dedicated to a corresponding one of modules 120a-120c to select which of modules 1120a-120c may utilize the control/address bus 130 and data bus 140 in a memory operation.
Here and in the detailed description to follow, xe2x80x9cbusxe2x80x9d denotes a plurality of signal lines, each having more than two connection points for xe2x80x9ctransceivingxe2x80x9d (i.e., transmitting or receiving). Each connection point electrically connects or couples to a transceiver (i.e., a transmitter-receiver) or one of a single transmitter or receiver circuit.
With further reference to FIG. 1, memory system 100 may provide an upgrade path through the usage of modules 120a-120c. A socket and connector interface may be employed which allows each module to be removed and replaced by a memory module that is faster or includes a higher capacity. Memory system 100 may be configured with unpopulated sockets or less than a full capacity of modules (i.e., empty sockets/connectors) and provided for increased capacity at a later time with memory expansion modules. Since providing a separate group of signals (e.g., address lines and data lines) to each module is avoided using the bussed approach, system resources in memory system 100 are efficiently utilized.
U.S. Pat. No. 5,513,135 discloses a contemporary dual inline memory module (DIMM) having one or more discrete buffer devices. In this patent, the discrete buffer devices are employed to buffer or register signals between memory devices disposed on the module and external bussing (such as control/address bus 130 in memory system 100). The discrete buffer devices buffer or register incoming control signals such as RAS, and CAS, etc., and address signals. Local control/address lines are disposed on the contemporary memory module to locally distribute the buffered or registered control and address signals to each memory device on the module. By way of note, the discrete buffer devices buffer a subset of all of the signals on the memory module since data path signals (e.g., data bus 140 in FIG. 1) of each memory device are connected directly to the external bus.
In addition to the discrete buffer device(s), a phase locked Loop (PLL) device may be disposed on the contemporary DIMM described above. The PLL device receives an external clock and generates a local phase adjusted clock for each memory device as well as the discrete buffer devices.
Modules such as the DIMM example disclosed in U.S. Pat. No. 5,513,135 feature routed connections between input/outputs (I/Os) of each memory device and connector pads disposed at the edge of the module substrate. These routed connections introduce long stub lines between the signal lines of the bus located off of the module (e.g., control address bus 130 and data bus 140), and memory device I/Os. A stub line is commonly known as a routed connection that deviates from the primary path of a signal line. Stub lines commonly introduce impedance discontinuities to the signal line. Impedance discontinuities may produce undesirable voltage reflections manifested as signal noise that may ultimately limit system operating frequency.
Examples of contemporary memory systems employing buffered modules are illustrated in FIGS. 2A and 2B. FIG. 2A illustrates a memory system 200 based on a Rambus(trademark) channel architecture and FIG. 2B illustrates a memory system 210 based on a Synchronous Link architecture. Both of these systems feature memory modules having buffer devices 250 disposed along multiple transmit/receive connection points of bus 260. In both of these examples, the lengths of stubs are significantly shortened in an attempt to minimize signal reflections and enable higher bandwidth characteristics. Ultimately however, memory configurations such as the ones portrayed by memory systems 100, 200 and 210 may be significantly bandwidth limited by the electrical characteristics inherent in the bussed approach as described below.
In the bussed approach exemplified in FIGS. 1, 2A and 2B, the signal lines of the bussed signals become loaded with a (load) capacitance associated with each bus connection point. These load capacitances are normally attributed to components of input/output (I/O) structures disposed on an integrated circuit (IC) device, such as a memory device or buffer device. For example, bond pads, electrostatic discharge devices, input buffer transistor capacitance, and output driver transistor parasitic and interconnect capacitances relative to the IC device substrate all contribute to the memory device load capacitance.
The load capacitances connected to multiple points along the length of the signal line may degrade signaling performance. As more load capacitances are introduced along the signal line of the bus, signal settling time correspondingly increases, reducing the bandwidth of the memory system. In addition, impedance along the signal line may become harder to control or match as more load capacitances are present along the signal line. Mismatched impedance may introduce voltage reflections that cause signal detection errors. Thus, for at least these reasons, increasing the number of loads along the bus imposes a compromise to the bandwidth of the memory system.
In an upgradeable memory system, such as conventional memory system 100, different memory capacity configurations become possible. Each different memory capacity configuration may present different electrical characteristics to the control/address bus 130. For example, load capacitance along each signal line of the control/address bus 130 may change with two different module capacity configurations.
As memory systems incorporate an increasing number of memory module configurations, the verification and validation of the number of permutations that these systems make possible may become increasingly more time consuming. Verification involves the confirmation of operation, logical and/or physical functionality of an IC by running tests on models of the memory, associated devices and/or bus prior to manufacturing the device. Validation involves testing the assembled system or components thereof (e.g., a memory module). Validation typically must account for a majority of the combinations or permutations of system conditions and possibilities which different memory configurations (e.g., 256 Mbyte, 1 Gbyte . . . ) present including signaling, electrical characteristics (e.g., impedance, capacitance, and inductance variations), temperature effects, different operating frequencies, different vendor interfaces, etc, to name a few. Thus, as the number of possible memory configurations increase, the test and verification time required also increases. More time required to test a system often increases the cost of bringing the system to market or delays a product introduction beyond an acceptable window of time to achieve competitiveness.
There is a need for memory system architectures or interconnect topologies that provide cost effective upgrade capabilities without compromising bandwidth. Using conventional signaling schemes, the bussed approaches lend efficiency towards resource utilization of a system and permits module interfacing for upgradeability. However, the bussed approach may suffer from bandwidth limitations that stem from the electrical characteristics inherent in the bus topology. In addition, impedance along a signal line may be increasingly more difficult to control with increased connection points along a signal line, introducing impedance mismatch and signal reflections. Utilizing the bussed approach in implementing an upgradeable memory system introduces many possible electrical permutations and combinations with each unique module configuration.
The present invention is directed toward memory system architectures (i.e., interconnect topologies) which include a controller communicating to at least one memory subsystem (e.g., a buffered memory module). An independent point-to-point link may be utilized between the controller and each memory subsystem to eliminate physical inter-dependence between memory subsystems. According to an embodiment, the memory system may be upgraded by coupling additional memory module(s), each via a dedicated point-to-point link to the controller. Bandwidth may scale upwards as the memory system is upgraded by the additional memory module(s).
In one aspect, the present invention is a memory system comprising a memory controller having an interface and at least a first memory subsystem. The interface includes a plurality of memory subsystem ports including a first memory subsystem port. The first memory subsystem includes a buffer device having a first port and a second port, and a plurality of memory devices coupled to the buffer device via the second port. A plurality of point-to-point links include a first point-to-point link. Each point-to-point link has a connection to a respective memory subsystem port of the plurality of memory subsystem ports. The first point-to-point link connecting the first port to a first memory subsystem port to transfer data between the plurality of memory devices and the memory controller.
In another aspect, the present invention is a memory system comprising a controller device and first and second buffer devices, each having a first interface and a second interface. A first point-to-point link includes a first connection to the controller device and a second connection to the first interface of the first buffer device. A first channel is connected to the second interface of the first buffer device, and a first plurality of memory devices are electrically coupled to the first channel. A second point-to-point link includes a first connection to the controller device and a second connection to the first interface of the second buffer. A second channel is connected to the second interface of the second buffer device, and a second plurality of memory devices are electrically coupled to the second channel.
In yet another aspect, the present invention comprises a controller device, and a first and second plurality of buffer devices, each buffer device having a first interface connected to a plurality of memory devices. First and second point-to-point links each include a first end connected to the controller device and a second end connected to a repeater device. A plurality of repeater links couple the first and second repeater devices to respective first and second pluralities of buffer devices.
In another aspect the present invention is a memory system comprising a controller device; a first, second and third connectors; and first second and third point-to-point links. Each of the respective first, second point-to-point links includes a first connection to the interface and a second connection to the respective first, second and third connectors. In this aspect the present invention also includes a first memory subsystem having a buffer device and a plurality of memory devices. The buffer device includes a first interface connected to the first connector, and a second interface connected to the plurality of memory devices. The second and third connectors may support coupling to respective second and third memory subsystems.
The present invention is described in the detailed description, including the embodiments to follow. The detailed description and embodiments are given by way of illustration only. The scope of the invention is defined by the attached claims. Various modifications to the embodiments of the present invention remain within the scope defined by the attached claims.

Memory system including a point-to-point linked memory subsystem


A belt attachment jig includes a jig body (10) located along a side surface of a pulley (1), and a belt guide portion (15) which protrudes forward in the pulley rotational direction from a contact portion (11) near one end of the jig body (10). The belt (B) is held between the twisting preventing plate (12) which forms the other end of the jig body (10) and the side surface of the jig-attached pulley (1) such that an inner circumferential surface of the belt (B) faces the jig-attached pulley (1). As the pulley (1) is rotated, the belt attachment jig is moved in the pulley rotational direction together with the belt (B) in a manner that makes the belt (B) fitted in the pulley groove.

In general, belt drive systems in which a belt is wrapped around a plurality of pulleys each having a pulley groove on its outer circumferential surface include a tension applying means, such as an auto tensioner, which applies predetermined belt tension after the belt is looped over all of the pulleys.
To avoid the provision of such a tension applying means, there is a belt which, when being attached to a plurality of pulleys, is extended in a circumferential direction and made to pass over the flange of the pulley, and a belt attachment jig for attaching the belt to the pulley has been suggested.
In the case for example where a belt is wrapped around two pulleys, the belt attachment jig is used in such a manner that the belt is looped over one of the two pulleys (a first pulley), and in this state, the belt is wound around the belt attachment jig and the belt attachment jig is attached to a second pulley. In this attachment state, the belt is wound around the belt attachment jig, and a belt portion located on the rear side of the belt attachment jig in the pulley rotational direction is fitted in the pulley groove of the second pulley, and a belt portion located on the forward side of the belt attachment jig in the pulley rotational direction is pulled laterally toward a near side of the second pulley. Accordingly, the belt attachment jig is sandwiched between the belt and the pulley groove. The phrase "near side" as used in this specification refers to the side closer to an operator who is attaching the belt, and the phrase "back side" refers to the side opposite to the side closer to the operator.
The belt attachment jig in this attachment state is moved forward in the pulley rotational direction by rotating the center bolt of the jig-attached pulley with a wrench, etc., to gradually increase the area of the belt which is fitted in the pulley groove, and make the belt completely wrapped around the jig-attached pulley in the end.
When the belt is wrapped around the pulleys as described above, the belt wound around the belt attachment jig passes through a lateral side of the near side of the jig-attached pulley and is led to the first pulley. Thus, if the belt is wrapped around the pulleys by rotating the second pulley, the belt entering to the first pulley may be pulled hard laterally toward the near side of the first pulley due to the tension generated by the wrapping of the belt. This may result in the detachment of the belt from the first pulley. To avoid the detachment of the belt, belt detachment preventing jigs for preventing the detachment of the belt have been known.
For example, Patent Document 1 discloses a belt detachment preventing jig including a plate-like detachment preventing member located on the rim of a pulley flange, and a fixing portion comprised of an engagement groove formed in the bottom of the detachment preventing member and a sandwiching portion which protrudes from the bottom of the detachment preventing member so as to extend along the inner surface of a pulley groove, wherein the pulley flange is sandwiched in the engagement groove, and the sandwiching portion is sandwiched between the belt and the pulley groove. Therefore, even if the belt is pulled laterally toward the near side of the pulley, the detachment preventing member prevents the detachment of the belt from the pulley.


Methods, systems, and apparatus for selecting frame loss measures are disclosed. In one aspect, a Synthetic Loss Measurement (SLM) report for a given interval for a network managed entity that includes at least two network nodes is received. A Loss Measurement Message (LMM) report for a given interval for the network managed entity is received. For the given interval and from the SLM and LMM reports, a reporting measurement for the network managed entity is selected based, at least in part, on a frame rate of data transmitted over the network managed entity during the given interval or an occurrence of a specified network event during the given interval. Frame loss information for the given interval for the network managed entity based on the selected reporting measurement is reported.

This specification relates to selecting frame loss measurement.
In a telecommunication network, frame loss rates for network managed entities are monitored and reported for network maintenance and optimizations. A network managed entity represents a connection between network nodes (e.g., network communication devices). For example, a network managed entity can be a data circuit that connects two or more network nodes. In some cases, a network node can report frame loss rates for the network managed entities that are associated with the network node.


A soft magnetic alloy powder containing Fe—Ni-based crystal particles is provided as one capable of adequately reducing core loss of a powder magnetic core and achieving satisfactory magnetic characteristics at an effective operating temperature of an element. The present invention provides a soft magnetic alloy powder containing Fe—Ni-based crystal particles containing 45 to 55 mass % Fe and 45 to 55 mass % Ni, relative to a total mass of Fe and Ni, and containing 1 to 12 mass % Co and 1.2 to 6.5 mass % Si, relative to a total mass of Fe, Ni, Co, and Si.

1. Field of the Invention
The present invention relates to a soft magnetic alloy powder, a compact, and an inductance element.
2. Related Background Art
Conventionally, a powder magnetic core is generally used as a type of magnetic core provided in an inductance element or the like. An Fe-based soft magnetic metal powder being a soft magnetic material is often used as a material of this powder magnetic core. Since the material of the Fe-based soft magnetic metal powder itself has low electric resistance, core loss becomes relatively high even if insulation between particles is enhanced. In recent years, according to the demand for downsizing of the inductance element or the like, it is to be desired that the electric resistance of the powder magnetic core is increased to decrease the core loss. For this reason, a further improvement is demanded for the conventional soft magnetic materials as described above. A technique of adding Si (silicon) in the metal powder was proposed in order to increase the electric resistance of the Fe-based soft magnetic metal powder. However, the addition of Si increases the hardness of the Fe-based soft magnetic metal powder, and thus moldability thereof becomes insufficient for the powder magnetic core and unsuitable for practical use.
Fe—Ni-based soft magnetic alloy (so-called permalloy alloy) powders are often adopted as materials of the powder magnetic core other than the Fe-based soft magnetic metal powder. However, reduction of core loss at high frequencies is insufficient in the Fe—Ni-based soft magnetic alloy powders. Then means of adding Si, Ge, or Sn being the Group 14 element was proposed for the purpose of reducing the core loss of the Fe—Ni-based soft magnetic alloy powders (cf. Patent Document 1). According to Patent Document 1, the electric resistance of the material itself increases when a predetermined amount of the Group 14 element such as Si is added in the Fe—Ni-based soft magnetic alloy powder.
Another example of addition of Si in the permalloy alloy likewise is the one disclosed in Patent Document 2. According to Patent Document 2, influence of oxygen on magnetic characteristics can be reduced by adding Si as a deoxidizing component. However, Patent Document 2 describes that Si should be limited to not more than 1 wt % because excessive addition of Si is harmful to the soft magnetic property. This Patent Document 2 also describes that Co may be added in the permalloy alloy in order to enhance the magnetic flux density or the like.
Patent Document 3 discloses use of Cr, Si, Cu, and Co as additive elements in the PC permalloy alloy, but describes nothing about an additive amount thereof.    [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-23811    [Patent Document 2] Japanese Patent Application Laid-Open No. 2002-173745    [Patent Document 3] Japanese Patent Application Laid-Open No. 63-114108

Soft magnetic alloy powder, compact, and inductance element


A time delay output apparatus for a circuit breaker includes a switch disposed at one side of a main shaft rotatable in directions to open/close a fixed contactor and a movable contactor, and a delay member disposed between the main shaft and the switch so as to operate the switch with a preset time delay, thereby simplifying the construction and reducing the size as well as enhancing operational reliability by stably obtaining a time delay.

1. Field of the Invention
The present invention relates to a time delay output apparatus for a circuit breaker, and more particularly, to a time delay output apparatus for a circuit breaker which is capable of preventing a malfunction caused by vibration, by excluding the use of a mass, thereby enhancing the operational reliability.
2. Description of the Background Art
In general, a circuit breaker is an protective electrical device disposed between a power source and a load equipment so as to protect the load equipment and an electrical line from a circuit fault (e.g., a large current due to a short circuit, earth fault, etc.) which may occur in an electrical circuit.
Some circuit breakers are provided with a relay performing an MCR (Making Current Release) function, which sets a current value, detects the introduced current, and instantaneously opens the circuit breaker when a large current greater than a reference value is introduced, thus to prevent the flow of the large current into the load side.
The relay blocks the electrical line within a preset allowable delay time. When the circuit breaker is closed to check whether or not a fault occurred in the electrical line, and if the fault is not completely solved, a large fault current flows for the preset allowable time in the electrical line, thereby causing damage in the electrical line and the load. When the circuit breaker is closed to check whether or not a fault occurred in the electrical line, and if a main contact is contacted and thus a fault current is detected, there is a need to instantaneously open the circuit breaker without maintaining the allowable (delay) time preset on the relay in order to reduce damage in the electrical line and the load. Such function is called the "MCR" function.
In order for the relay to perform the MCR function, two cases should be distinguished: one case is where the fault current is blocked (i.e., a fixed contactor and a movable contactor are separated) when the circuit breaker is closed, and another case is where the fault current is blocked (i.e., the fixed contactor and the movable contactor contact each other) when the circuit breaker is closed on an electrical line where the circuit breaker had been opened due to a previously occurred fault. In order to distinguish such two cases, there is provided a time delay output apparatus for a circuit breaker, which outputs a contact signal with a certain delay time after the fixed contactor and the movable contactor contact each other.
As shown in FIGS. 1 and 2, the time delay output apparatus for a circuit breaker includes a switch 20 disposed at one side of a main shaft 10 so as to output a signal when a contact is detected, a delay plate 30 disposed pivotably with respect to a detection portion of the switch 20 so as to contact and be separated from the detection portion of the switch 20, and a lever 12 integrally formed with the main shaft 10, and pressing and pivoting the delay plate 30 so as to be separated from the switch 20 when the main shaft 10 is rotated in an opening direction.
The delay plate 30 includes a pivot shaft 31, a first arm 33 extending from the pivot shaft 31 to the main shaft 10 and contacting the lever 12, and a second arm 35 extending from the pivot shaft 31 to the switch 20 and contacting the detection portion of the switch 20 by being pivoted together with the first arm 33. A spring 37 is connected to the second arm 35 so as to apply an elastic force in a direction urging the second arm 35 to contact the switch 20.
Meanwhile, the second arm 35 is provided with a mass 39 for generating a certain time delay by inertia when the main shaft 10 is rotated in a closing direction.
With such construction, when the circuit breaker is opened, as shown in FIG. 1, the lever 12 presses the delay plate 30, and thus the delay plate 30 is spaced apart from the switch 20. When the main shaft 10 is rotated in a closing direction (i.e., in a counter-clockwise direction in the drawing), the delay plate 30 is pivoted toward the switch 20 in a clockwise direction in the drawing by the urging force of the spring 37. Here, while the delay plate 30 is pivoted, a certain delay is generated by inertia of the mass 39. Such delay serves to output a signal from the switch 20 once the delay plate 30 contacts the detection portion of the switch 20 after the fixed contactor and the movable contactor contact each other by the rotation of the main shaft 10.
However, in this conventional time delay output apparatus for a circuit breaker, a relatively large mass 39 is required to generate a certain (fixed) delay, thereby increasing the size of the time delay output apparatus.
In addition, when a large current is introduced, the inertia when the mass 39 is vibrated or moved by vibration generated by electromagnetic repulsion force becomes more reduced, compared to that of when the mass 39 is stopped. Accordingly, the delay plate 30 cannot maintain the preset delay. Consequently, the switch 20 outputs a signal too early, and the circuit breaker is instantaneously opened, thereby not performing its function properly.

Time delay output apparatus for circuit breaker


A method for testing a data storage system. The data storage system contains a buffer area, firmware and a storage area. The method including: selecting at least one product testing item, commanding the firmware to execute a starting process in order to transfer the storage system from general working mode to testing mode, commanding the firmware to execute a testing process corresponding to the selected product testing item, the executed testing process generates a testing result, displaying the result; and commanding the firmware to execute an ending process in order to return the storage to general working mode. Users use an application program to give commands to the firmware after requesting disc access service from the computer operation system. The buffer area can be a RAM (Random Access Memory). The testing result can be displayed on a computer monitor.

A data storage system contains a data storage device and the access device thereof. Traditional data storage devices include hard discs, floppy discs, and memory cards. As capacity and utility of the flash memory and other non-volatile memory are improved and the prices thereof are reasonable, portable data storage devices containing flash memories are popular such as Compact Flash memory card (CF card), Smart Media Flash card (SM card), portable flash memory driver adaptable to computer USB port. The access devices include all kinds of readers for the data storage device such as CF card reader.
After the data storage devices and the access devices are manufactured. They have to be tested in order to control the quality of the products. The test includes writing parameters to the data storage devices, reading the parameters of the data storage devices, self-test, code setting, updating firmware, testing memory devices such as flash, low level formatting storage elements, reading storage elements statuses and so on.
A conventional method of testing the data storage system includes writing a new driver or modifying a standard driver, so test personnel can operate an application program under a computer operating system to test the products through a test platform such as a card reader or other access devices. The access devices can be an integrated hard disc integrating both the functions of a card reader and a data storage device. However writing a new driver or modifying a standard driver burdens the cost of research and development. Besides modifying standard driver sometimes will cause computer system unstable. In addition, when the computer operating system is upgraded or the interfaces of the test platforms are no longer supported by the computer, the test will be interrupted. Therefore a method for testing a data storage system that can reduce the cost of test and will not be interrupted by system upgrading is needed.

Data storage system and method for testing the same


An improved fuel system for a dual-fuel internal combustion engine. During normal operation, the primary fuel passes through a pressure regulator before arriving at a primary fuel rail. Further, pressurized secondary fuel is delivered to both a secondary fuel rail and to the pressure regulator for purposes of regulating the output pressure of the primary fuel that is delivered to the primary fuel rail. When the pressure at the primary fuel supply or between the primary fuel supply and the pressure regulator drops below a minimum operating pressure, the pressure regulator is isolated from the secondary fuel and the secondary fuel continues to be pressurized until it reaches a suitable pressure for operating in a limp mode. Then, the secondary fuel, which is pressurized to greater than a normal operating pressure, may be injected at the higher pressure for improved performance of the engine in the limp mode.

This disclosure relates to high-pressure direct-injection (HPDI) fuel systems designed to inject a primary fuel, such as natural gas, and a pilot fuel, such as diesel, into a combustion chamber, for example a cylinder of a reciprocating internal combustion (IC) engine. More specifically, this disclosure describes an HPDI system that features a "limp mode" when the supply of natural gas is depleted or otherwise interrupted. Still more specifically, this disclosure describes a control system and method for generating and isolating high-pressure pilot fuel in an HPDI system when operating in a limp mode.
Heavy-duty IC engines that run on natural gas instead of diesel are desirable because natural gas has cost advantages and produces fewer emission products compared to diesel. Engines that burn natural gas may be spark-ignited or compression-ignited. Spark-ignited engines are available, but spark-ignited engines that run on natural gas have reduced efficiencies and lower torques at low speeds when compared with traditional diesel engines. However, spark-ignited engines that run on natural gas are commonly used for transit buses, delivery vehicles, shuttles, street sweepers and other applications that do not require high torque and low speeds.
Compression-ignited engines that burn natural gas also burn some diesel as a pilot fuel and are therefore referred to as dual-fuel engines. Fuel systems for dual-fuel compression-ignited engines come in two types: substitution systems and high-pressure direct injection (HPDI) systems. Substitution systems simply add natural gas to the intake air stream and decrease the amount of diesel fuel, thereby "substituting" a percentage of the diesel with natural gas. Drawbacks of substitution systems include reduced power output because introducing natural gas into the intake air system reduces the amount of air drawn into the engine, and the amount of natural gas that can be substituted is limited by engine knock limits to avoid premature detonation of a premixed charge of natural gas and air. Engines equipped with substitution systems will run either on natural gas and substantial amounts of diesel or pure diesel (with no natural gas), but will not run primarily on natural gas. The substitution percentage of diesel with natural gas typically ranges between 0 and 65%, dependent upon the load and operating conditions. While substitution systems account for the majority of diesel/natural gas engines in use today, the inability to run on natural gas without substantial amounts of diesel renders substitution systems less environmentally friendly than HPDI systems. Further, substitution systems do not provide the fuel cost savings provided by HPDI systems when natural gas is less expensive than diesel fuel.
HPDI systems burn primarily natural gas with a small amount of diesel as a pilot fuel. The diesel is injected into the cylinder just prior to the injection of high-pressure natural gas to provide the ignition. Typically, the diesel amounts to less than 10% of the combusted fuel and therefore the emission reduction is substantial. Engines equipped with HPDI fuel systems offer power, torque and efficiency similar to that of traditional diesel engines. Further, a traditional diesel engine may be converted to an HPDI engine by replacing the diesel fuel system with an HPDI fuel system.
Current HPDI systems may run on diesel only, for those situations where the natural gas supply is depleted or natural gas is otherwise not available, or for extremely cold starts when the engine is too cold to effectively vaporize the natural gas stored in liquefied form, as disclosed in CA 2849623. During normal operations, when diesel is used as a pilot fuel, the diesel and natural gas are pressurized to a normal system pressure of about 30 MPa. However, when the engine is operating in a limp mode (also known as a limp-home mode, run-on diesel (ROD) mode and diesel only mode (DOM)), injecting diesel at the normal operating pressure provides only about 10% of the engine power. Operating at such a reduced power is very disadvantageous for some applications, such as mine haul trucks, where substantial power may be needed to move a truck off the haul road. Further, trucks with HPDI systems may need to travel substantial distances or climb steep inclines to reach a site where the natural gas supply can be replenished.
A solution to this problem would be to increase the pressure of the diesel from the normal operating pressure of about 30 MPa to a higher pressure of about 100 MPa while operating in the limp mode, but certain components of an HPDI system, such as the pressure regulator, cannot withstand the excessive force imbalance between the normal operating pressure and the high pressure needed to run on diesel only. Thus, a need exists for an HPDI fuel system and method that delivers high-pressure diesel (or high-pressure secondary fuel) to the engine when the engine is operating in a limp mode without compromising components needed to operate the engine in a normal operating mode.

Control system and method for isolating high pressure pilot fuel in dual-fuel HPDI system


A shift control system for a continuously variable traction roller transmission controls the feedback to a shift control valve so that a ratio b/a of a variation "b" mm of a feedback amount to the shift control valve for 1 mm of a displacement of a power roller to a variation "a" mm of the feedback amount to the shift control valve for 1 degree of an inclination of the power roller is in a range given by: 1.74R.sup.4/5 -3.90.ltoreq.b/a.ltoreq.3.09R.sup.5/9 +30.51.

The present invention relates to a shift control system for a continuously variable traction roller transmission.
One of the previously proposed continuously variable traction roller transmissions is disclosed, for example, in JP-A 2-163567. Such a continuously variable transmission may use a shift control system as shown in FIGS. 64-66.
Referring to FIGS. 64-66, 1 generally designates a power roller which is interposed between input and output toroidal disks 2, 3 disposed axially perpendicular thereto. An opposed surface of each of the input and output toroidal disks 2, 3 is a toroidal surface, whereas a periphery of the power roller 1 is a spherical surface which is contact therewith. Thus, torque to the input toroidal disk 2 is transmitted to the output toroidal disk 3 via rotation of the power roller 1. By slantly rotating the power roller 1 about a slant rotation axis O.sub.2 perpendicular to a rotation axis O.sub.1 thereof to vary a position of contact with the input and output disks 2, 3, the input/output rotation ratio or speed ratio can be changed steplessly.
While the power roller 1 occupies a position to put the rotation axis O.sub.1 at the same level as a rotation axis O.sub.3 of the input and output corn disks 2, 3, it preserves the inclination or speed ratio at the same value, whereas when the power roller 1 is moved in the direction of the slant rotation axis O.sub.2 to put the rotation axis O.sub.1 offset from the rotation axis O.sub.3 of the input and output disks 2, 3, it slantly rotates by itself in the direction corresponding to the offset direction to vary the inclination. From the foregoing, when controlling this continuously variable transmission, the following shift control method is adopted:
A trunnion 4 for rotatably supporting the power roller 1 is not only rotatable about the slant rotation axis O.sub.2, but movable in the direction of slant rotation axis O.sub.2. This displacement is produced by a plurality of servo pistons 5 which are in turn controlled in stroke by a shift control valve 6. For that purpose, the shift control valve 6 has an input port 6a to which a line pressure is supplied, and output ports 6b, 6c connected to chambers on both sides of each servo piston 5, respectively. Additionally, the shift control valve 6 receives a speed ratio command from a pinion 7 driven by a stepper motor (not shown). An input sleeve valve body 8 is stroked in accordance with this command, so that a relative position thereof with respect to a feedback spool valve body 9 is changed from a balance position as indicated in FIG. 65. Thus, the shift control valve 6 supplies in response to a new speed ratio command a line pressure of the input port 6a from the one output port 6b to the corresponding side of each servo piston 5, and drains the opposite side thereof from the other output port 6c, putting the power roller 1 offset in the corresponding direction and with respect to the input and output toroidal disks 2, 3. Under such offset conditions, the power roller 1 changes the inclination by itself in the direction corresponding to the speed ratio command.
The displacement or offset to the slant rotation axis O.sub.2 and slant rotation of the power roller 1 are transmitted, via the displacement to the slant rotation axis O.sub.2 and rotation of a precess cam 10 connected to the power roller 1, to a link 11 which is in contact with a cam face 10a thereof, and are fed back to the feedback spool valve body 9 of the shift control valve 6 via rotation of the link 11 about a shaft 12. The link 11 is an L-shaped lever, and has one lever arm in contact with the cam face 10a of the precess cam 10, and the other lever arm abutting on the feedback spool valve body 9 via an adjust screw 13 engaged therewith. This feedback enables the feedback spool valve body 9 to follow the displacement of the input sleeve valve body 8 in response to the speed ratio command so as to regain the initial relative position with respect to the input sleeve valve body 8. Accordingly, as soon as the power roller 1 has the inclination corresponding to the speed ratio command, the shift control valve 6 puts at zero the offset of the power roller 1 via the servo pistons 5, preserving the inclination or speed ratio.
With such a shift control system for a continuously variable traction roller transmission, it is preferable that a response lag is small which is produced between receiving of the speed ratio modifier command and achievement of the corresponding inclination of the power roller 1, and that the speed ratio converges quickly on a speed ratio command value with small frequency of vibrations or hunting which is produced until the inclination of the power roller 1 or speed ratio settles to the command value during a transition period of modification of the speed ratio.
One of the factors affecting such shift control performances is the type of the shift control valve 6. When using an overlap type shift control valve, i.e., the shift control valve wherein valve port parts of the input sleeve valve body 8 and the feedback spool valve body 9 overlap or engage each other in a balance state thereof after completion of the shift, relatively frequent hunting is produced. On the other hand, when using an underlap type shift control valve, i.e., the shift control valve wherein the valve port parts of the two valve bodies 8, 9 do not engage each other to keep valve ports open even in the balance state thereof, the response lag is larger, so that the shift control is practically difficult to carry out.
On the other hand, referring to FIG. 65, there is a just lap type shift control valve, i.e., the shift control valve wherein the valve port parts of the two valve bodies 8, 9 just close the valve ports in the balance state thereof. However, although not as considerable as compared with the underlap type shift control valve, the just lap type shift control valve is not free from a constant leakage of hydraulic fluid out of the valve ports even in the balance state of the shift control valve, thereby enlarging energy loss of an engine for driving an oil pump.
It is, therefore, an object of the present invention to provide a shift control system for a continuously variable traction roller transmission including an overlap type shift control valve which is free from not only the problem of hunting, but also response lag.

Shift control system for continuously variable traction roller transmission


An article of footwear includes an outsole having a bottom walking surface and a depressed top surface surrounded by an upstanding peripheral sidewall having a upper peripheral edge, an upper attached to the outsole, and a replaceable inner sole. The upstanding peripheral sidewall and depressed top surface of the outsole together define a cavity lying generally below the upper peripheral edge. The upper and outsole together define a volume disposed over the cavity and generally above the upper peripheral edge, the volume sized comfortably accommodate a wearer's foot. The replaceable inner sole has a body sized and shaped to fit snugly within the cavity portion, generally removed from encroachment of the volume, while supporting a wearer's foot within the volume.

The invention relates to footwear.
A typical shoe or boot includes an outsole which is attached to an upper lasted to an insole. The insole and upper together define a volume for receiving and protecting a wearer's foot. In certain constructions, the insole may be covered by a "sock-lining" formed of leather or synthetic material and inserted within the already-completed shoe. The sock-lining is designed to provide comfort, warmth and support to the wearer's foot. The sock-lining may also be of the type used to combat foot odor. Such sock-linings or other footbeds must be quite thin so as to consume only a relatively small portion of the volume intended for the wearer's foot, thus to avoid adversely affecting shoe fit.


A tamper resistant hourmeter is provided for an engine powered lawn mower. The hourmeter has a first pin connected to a positive voltage from a battery through a key actuated switch, a second pin to ground, a third pin to a magneto ignition, and a fourth pin to a fuel shutoff solenoid. The tamper resistant hourmeter connects the positive voltage from the battery to the fuel shutoff solenoid. The fuel shutoff solenoid opens a fuel line to the engine only if the key actuated switch is in either of the run or start positions.

Grass mowing machines and other vehicles powered by internal combustion engines may be provided with hourmeters that track and display the cumulative time the engine has operated. The information may be used for a number of different purposes including vehicle warranty, service and maintenance scheduling, rental usage, or determining resale value. The following patents provide examples of hourmeters for such vehicles.
U.S. Pat. No. 4,630,292 entitled "Fuel Tax Rebate Recorder" relates to a system for recording the total time that a motor vehicle is running, including three electrically driven timers, one of which is connected in series with the oil pressure switch of the motor so that the timer is energized while the motor is running.
U.S. Pat. No. 5,337,003 entitled "Self-Contained Clip-On Engine Operating Time Log" relates to a sensor and circuitry to detect spark impulses in the ignition wire for determining the operating time of the engine.
U.S. Pat. No. 5,644,491 entitled "Self Contained Multi-Function Engine Monitor and Timer for Providing Engine Running Time, Job Time, Service Time and Tachometer Functions" relates to an engine monitor coupled to a spark pick up wire, and provides total running time, job time and service time metering
U.S. Pat. No. 5,644,551 entitled "Adaptable Engine Usage Meter" relates to a meter connected to the ignition wire of a mower engine, and mounted on a mower handlebar.
U.S. Pat. No. 6,609,357 entitled "Lawn and Garden Control Module" relates to a controller for monitoring inputs relating to status of a mower/tractor for determining a safety status condition and inhibiting operation in response to a determination of a safety status condition.
U.S. Pat. No. 6,972,668 entitled "Tamper-Evident Use-indicating Odometer and Engine-Timer" relates to a tamper evident combined odometer and engine time recorder.
Some mowing vehicle warranties may be hour-limited. However, if the hourmeter is unplugged, the engine can run without accumulating time on the hourmeter. This would allow a user to unplug the hourmeter and continue operating the lawn mower without falling out of the warranty period.
A tamper resistant hourmeter is needed for a grass mowing machine to ensure time is recorded and accumulated while the engine is running. A tamper resistant hourmeter is needed that will prevent a user from unplugging it for unrecorded use of the mower.


A diffraction grating for generating a plurality of beams includes a plurality of gratings. The plurality of gratings are formed to have an axis of symmetry perpendicular to the direction in which a beam is divided on a surface of diffraction grating and include at least two gratings having different fundamental cycles. The plurality of gratings are formed such that they have an axis of symmetry perpendicular to the direction in which a beam is divided on a surface of the diffraction grating, for generating a plurality of beams. The fundamental cycle increases as a function of the distance from the axis of symmetry, and therefore aberration in the periphery of scattering light may be reduced.

1. Field of the Invention
The present invention relates generally to diffraction gratings for generating a plurality of beams and multi-beam pickups for recording/reproducing simultaneously to/from a plurality of tracks on an optical recording medium. The invention relates particularly to a diffraction grating having a plurality of gratings with different cycles for generating a plurality of beams and an optical pickup using such a diffraction grating.
2. Description of the Background Art
Various optics-related techniques have been researched, developed and reduced to practice in a variety of fields including communication, measurement and processing, because they permit operations at high a frequencies (high speeds), spatial information processing, phase processing and the like.
Among such techniques, the use of diffraction gratings and holograms as elements for selecting wavelengths, deflecting light, and generating a plurality of beams is known. For example, a diffraction grating in a spectroscope is used for separating a light component with a different wavelength in an incident light beam, and has a constant grating cycle.
Japanese Patent Laying-Open No. 5-264923 proposes a hologram scanner using a hologram for deflecting and collecting light as an application to a laser printer. According to this document, a light beam emitted from a semiconductor laser as an optical source is allowed to come into a plurality of scan holograms formed on a hologram disc. A light beam diffracted and deflected by the scan holograms is used to form an image on a scanning surface (photoreceptor drum), and the deflection angle of the diffracted light beam is changed by the rotation of the hologram disc for scanning. In order to correct characteristics on the scanning surface such as astigmatism and curvature of field, a grating pitch for the scan hologram is two-dimensionally modulated.
There is known such an information recording/reproducing apparatus in which an optical information recording medium (optical disc) is used, a plurality of beams are generated in an optical pickup for reading information, and the plurality of beams are directed at the optical disc at a time to obtain a signal. In the optical pickup, a diffraction grating is used to generate a plurality of beams (see Japanese Patent Laying-Open No. 1-269239 for example). Such a diffraction grating used for an optical pickup will be now described in detail.
First Conventional Example
Japanese Patent Laying-Open No. 1-269239 discloses an optical pickup including a diffraction grating for dividing a beam, a hologram element for dividing light for RES (Radial Error Signal) and FES (Focus Error Signal), and a laser source as they are integrally formed.
FIG. 1 is a view of the 3-beam optical pickup described above. Divergent light emitted from a semiconductor laser 112 as an optical source is divided into a plurality of beams by a diffraction grating 113, each transmitted through hologram element 114 as the zeroth-order diffracted light and comes into a collimator lens 115. The beams formed into parallel rays by collimator lens 115 are collected into a small enough spot on a disc 117 by an objective lens 116, and reflected as an optical beam reflecting information on disc 117. The reflected light is passed through objective lens 116 and collimator lens 115 and divided into the zeroth-order diffracted light beam and the first-order diffracted light beam by hologram element 114. The first-order diffracted light beam is allowed to come into an internal light receiving portion 118 including an RES light receiving portion, an FES light receiving portion and an RF (Radio Frequency) signal light receiving portion.
Herein, semiconductor laser 112, diffraction grating 113, hologram element 114 and internal light receiving portion 118 are built integrally as a hologram laser unit 119. Diffraction grating 113 divides a light beam into three beams, the zeroth-order diffracted light beam and the xc2x1first-order diffracted light beams, and the zeroth-order light beam is used as an RF signal and an FES, while the xc2x1first-order diffracted light beams are used as an RES. Therefore, the tracking employs the 3-beam method.
Second Conventional Example
A multi-beam optical pickup is proposed by which an optical recording medium is irradiated with a plurality of beams, which are used to record/reproduce information simultaneously to/from a plurality of tracks on the optical recording medium (Japanese Patent Laying-Open No. 1-248329).
The multi-beam optical pickup will be now described in conjunction with related figures. FIG. 2 is a view of an optical system. A light beam emitted from a semiconductor laser 102 as an optical source is formed into parallel light with a collimator lens 104, then let into a diffraction grating 103 and divided into a plurality of beams. Then, each of the beams is passed through a beam splitter 105, collected into an optical spot small enough on a disc 107 by an objective lens 106 and reflected and passed through objective lens 106 as a light beam reflecting information on disc 107. The light beam is reflected by beam splitter 105, and let into a light receiving portion 110 through a light collecting lens 108 and a cylindrical lens 109.
When a light beam is divided into for example three beams with a diffraction grating, the zeroth-order diffracted light beam (referred to as main beam) of diffraction grating 103 in the center on disc 107, and the xc2x1first-order diffracted light beams (referred to as sub beams) on opposite sides thereof are arranged in order to simultaneously perform reading with the three beams in total.
In the diffraction gratings used in the conventional pickups according to the first and second conventional examples, as shown in the plan view in FIG. 3 and the cross sectional view in FIG. 4, a grating recess 121 and a grating ridge 122 in diffraction grating substrate 130 are formed along straight lines and over an aperture surface in a constant grating cycle pn.
In the hologram scanner used for a laser printer disclosed by Japanese Patent Laying-Open No. 5-264923, the diffraction grating formed in the hologram is used for deflecting a single incident beam and does not divide this single beam into a plurality of beams. This is because this application requires a great beam intensity after diffraction, so if the beam is divided into a plurality of beams, the intensity of each diffracted light beam could be lowered, and a necessary beam intensity could not be obtained on the scanning surface. Therefore, only a diffracted light beam of the lowest order is typically used.
As a result, there is not disclosed in the document any such concept of correcting aberration in the diffracted light beam of the highest order when a plurality of high order diffracted light beams are used. The grating is formed to have curves in order to converge a beam spot in the X-direction (main scanning) and the Y-direction (sub scanning) on the scanning surface.
As described above, the diffraction grating of the optical pickup according to the first and second examples typically includes a straight line grating of an equal pitch as shown in FIGS. 3 and 4. In such a case, particularly in a multi-beam optical pickup which records/reproduces information to/from a plurality of tracks using a plurality of optical beams, the following problem is encountered.
In a multi-beam optical pickup, if the intervals Pd of beams on the disk is equal, the relation between Pd and the intervals Ph of the beams at the internal light receiving portion is given as follows:
Pd=Phxc2x7fOL/fCL
wherein the focal distance of the objective lens is fOL and the focal distance of the collimator lens is fCL.
In order to use a number of beams for recording/reproducing at a time, Pd should be small. To reduce Pd, Ph must be reduced or fCL must be increased. However, Ph is under restrictions as to the photoelectric conversion sensitivity and processing/assembling precision of the light receiving element and cannot be arbitrarily reduced, while the effective numerical aperture of the collimator lens is reduced by increasing fCL, which degrades the use efficiency of light. Therefore, the allowable image height on the disc determined by the aberration of the objective lens, collimator lens, diffraction grating, the disc and the like must be increased as much as possible.
In a conventional multi-beam optical pickup, however, a beam dividing diffraction grating having a straight line grating groove and a constant grating cycle over an aperture surface is employed, and therefore, the aberration is small for parallel light, while the aberration could be great for divergent rays as in the construction of the optical pickup disclosed by Japanese Patent Laying-Open No. 1-269239, which has been a main cause for degradation in the aberration of the entire optical system.
For example, FIG. 5 shows the wave front aberration of each beam in such a conventional multi-beam optical pickup, while FIG. 6 shows the wave front aberration derived from the diffraction grating therein. Herein, the image height refers to the position of the diffracted beam using the zeroth-order diffracted light beam on the disc as the origin.
When the reference value of each of beam wave front aberration (r. m. s. value) is 0.07xcex (Marechal Criterion), the maximum allowable image height is about 25 xcexcm. Therefore, if each of the beam intervals on the disc is 9 xcexcm, only the beams up to the xc2x1second-order diffracted beams may be available (2xc3x979=18 xcexcm less than 25 xcexcm), and therefore reading with five beams is performed. In practice, however, the number of beams is smaller when the aberration and assembling errors of the optical elements constituting the pickup are taken into account.
As a result, the wave front aberration value in the xc2x1third-order diffracted light beams exceeds the reference value as described above when the assembling tolerance of the elements is taken into account, and all the beams cannot be used for reading.
As can be seen from FIGS. 5 and 6 in comparison, a large part of the aberration of an optical system derives from the aberration of a diffraction grating.
FIG. 7 shows the wave front aberration of an optical system excluding a diffraction grating, FIG. 8 shows the wave front aberration of only the diffraction grating and FIG. 9 shows the wave front aberration of the entire optical system including the diffraction grating, each with xc2x1third-order diffracted light beams (when the image height is 0.027 mm). The wave front aberration of only the diffraction grating is in the same direction as that of the wave front aberration of the optical system excluding the diffraction grating and both aberrations are added and given in FIG. 9 as the entire wave front aberration.
As described above, in such a conventional optical pickup, straight line diffraction gratings having an equal pitch are used, the aberration for a divergent luminous flux is great, the allowable image height cannot be increased, and the number of beams cannot be increased. As a result, the spot size of the sub beams on the high image height side cannot be reduced sufficiently, which adversely affects the jitter characteristic, and reading cannot be performed at sufficiently high speeds.
As described above, conventional diffraction grating having straight line gratings of an equal pitch cannot be used for applications which require high-order beams such as a multi-beam optical pickup.
Japanese Patent Laying-Open No. 7-302435 (hereinafter as the third conventional example) discloses the use of diffraction gratings having unequal pitches as a reflective type diffraction grating for dividing a beam into three in a pickup using the 3-beam method for tracking control, which will be now described.
Herein, as shown in FIG. 10, a beam emitted from a semiconductor laser 147 has its advancing direction turned by 90xc2x0 and is divided into three beams using a reflective type diffraction grating 81 positioned at an angle of 45xc2x0 with respective to the optical axis. Each of the beams is collected on a disc 146 through a hologram element 149 and a light collecting lens 145. A light beam reflected from disc 146 is passed through light collecting lens 145, goes through the first-order diffraction (orxe2x88x92first-order diffraction) by hologram element 149 and let into a light receiving element 150.
In a pickup using a reflective type diffraction grating, since the optical axis of incident light into the diffraction grating is inclined, the distance between the zeroth-order diffracted light beam and the xc2x1first-order diffracted light beams is asymmetrical. According to the third conventional example, diffraction grating 81 is formed to have a cycle longer along the direction of the arrow X as shown in FIG. 11 in order to correct this asymmetry.
More specifically, diffraction grating 81 according to the third conventional example has unequal pitches and this is for the purpose of correcting the diffracted light beam so that the +first-order diffracted light beam and xe2x88x92first-order diffracted light beam will be symmetric with respect to the zeroth-order diffracted light beam, rather than correcting the aberration of the xc2x1second or higher order diffracted light beams, and if the xc2x1first-order diffracted light beams satisfy the conditions of a defined wave front aberration, it does not mean that beams of higher orders also satisfy the conditions of the wave front aberration. According to the third conventional example, a method of designing to satisfy a prescribed wave front aberration for beams of xc2x1second or higher orders is not suggested.
In the multi-beam optical pickup described above, the wave front aberration of higher order diffracted light beams should also be equal to or lower the defined level, and therefore the diffraction grating according to the third conventional example cannot be applied.
In addition, the third conventional example is directed to a solution to the asymmetry of the xc2x1first-order diffracted light beams unique to the reflective diffraction grating, and a transparent type diffraction grating having the xc2x1first-order diffracted light beams being symmetric is not addressed by the third conventional example.
As a result of research by the inventors, however, it was found that the wave front aberration of a higher order diffracted light beam was particularly disadvantageous when a divergent luminous flux was used in a transparent diffraction grating as shown in FIGS. 5 and 6.
Furthermore, although the grating according to the third conventional example is formed by straight lines, such straight line grating can only reduce the wave front aberration to a limited level.
It is an object of the present invention to provide a diffraction grating for generating a plurality of beams which can restrain the front wave aberration of higher order sub beams as well as a main beam.
Another object of the present invention is to provide a diffraction grating for generating a plurality of beams which permits the spot size of each beam to be sufficiently limited and the jitter characteristic to be improved.
Yet another object of the present invention is to provide a multi-beam optical pickup which can restrain the wave front aberration of higher order sub beams as well as a main beam.
A still further object of the present invention is to provide a multi-beam optical pickup which permits the spot size of each beam to be sufficiently limited and the jitter characteristic to be improved.
According to one aspect of the present invention, the diffraction grating for generating a plurality of beams includes a plurality of gratings formed to have an axis of symmetry perpendicular to the direction in which a beam is divided on the surface of the diffraction grating and includes at least two gratings having different fundamental cycles.
The diffraction grating for generating a plurality of beams includes a plurality of gratings on the surface of thereof formed to have an axis of symmetry perpendicular to the direction in which a beam is divided, and at least two of the plurality of gratings have different fundamental cycles, so that the aberration in the periphery of divergent light may be reduced.
According to another aspect of the present invention, the diffraction grating for generating a plurality of beams includes a plurality of gratings, which are formed in a curved shape on the surface of the diffraction grating and include at least two gratings having different fundamental cycles.
The diffraction grating have a plurality of gratings formed in a curved shape on the surface thereof and at least two of the plurality of gratings have different fundamental cycles, so that the aberration in the periphery of divergent light may be reduced.
According to a further aspect of the present invention, a multi-beam optical pickup includes a semiconductor laser, a diffraction grating for generating a plurality of beams having a plurality of gratings which have an axis of symmetry perpendicular to the direction in which a beam is divided on the surface and at least two of which have different fundamental cycles, a hologram element for transmitting a light beam transmitted through the diffraction grating for generating a plurality of beams and reflected from a recording medium, and an internal light receiving portion for receiving a light beam transmitted through the hologram element.
The diffraction grating for generating a plurality of beams have a plurality of gratings which have an axis of symmetry perpendicular to the direction in which a beam is divided on the surface thereof, and at least two of which have different fundamental cycles, and therefore the wave front aberration of the diffraction grating for generating a plurality of beams may be reduced, so that the wave front aberration of the entire optical system including the diffraction grating for generating a plurality of beams may be reduced.
According to an additional aspect of the present invention, a multi-optical pickup includes a semiconductor laser, a diffraction grating for generating a plurality of beams having a plurality of gratings which are formed in a curved shape on the surface and at least two of which have different fundamental cycles, a hologram element for transmitting a light beam transmitted through the diffraction grating for generating a plurality of beams and reflected from a recording medium, and a internal light receiving element for receiving a light beam transmitted through the hologram element.
The diffraction grating have a plurality of gratings which are formed in a curved shape on the surface and at least two of which have different fundamental cycles, and therefore a wave front aberration in the opposite direction to the wave front aberration of the optical system excluding the diffraction grating for generating a plurality of beams may be generated in order to reduce the wave front aberration of the entire optical system including the diffraction grating for generating a plurality of beams.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.

Diffraction grating having multiple gratings with different cycles for generating multiple beams and optical pickup using such diffraction grating


Starch hydrolysates having a D.P. of about 20 to 200 and a D.E. of about 0.5 to 5 are used as fat replacements in food. The starch hydrolysates are prepared by heating granular starch containing at least about 20 weight percent amylopectin in an acidic slurry of water and a water-miscable organic solvent such as ethanol. The slurry is heated under conditions which do not gelatinize the starch but cleave at least about 20 percent of the terminal amylose groups from the amylopectin molecules.

Fats and oils are compounds widely used in food. There is no chemical difference between a fat and an oil, the only distinction being that fats are solid at room temperature while oils are liquid. For simplicity, the term fat will be used throughout to include both fats and oils. Fats form one of the three classes of foods, the other two being carbohydrates and proteins. Fats contain more than double the number of calories per unit weight of carbohydrates or proteins. Furthermore, fats in the diet have become linked with a wide number of other undesirable effects on humans, ranging from heart disease to cancer. While these undesirable effects are now widely recognized, the taste, mouthfeel, and other organoleptic properties of fat in food are so desirable that it is not feasible to simply omit fat from food. Accordingly, it would be beneficial to reduce or eliminate the level of fat in food by replacing it with other materials which mimic fat's organoleptic and functional properties. A wide variety of fat replacements and substitutes have been taught for this purpose, including sucrose polyesters, pectin, carageenan, protein microparticulates, beta-glucans, and hemicelluloses. However, to date, starch derivatives of various types have shown the most promise in serving as acceptable fat replacements.
Starch is a plant material whose chemical composition is a polymer of thousands of anhydroglucose (C.sub.6 H.sub.10 O.sub.5) units. It is a member of the class of compounds known as polysaccharides in that it contains three or more saccharide units. It is also a member of the broader, carbohydrate class of compounds, which class includes monosaccharides, disaccharides, and polysaccharides. Starch molecules exist as essentially unbranched chains consisting predominantly of 1,4-linkages between the anhydroglucose units, known as amylose, and as branched chains consisting of both 1,4- and 1,6-linkages, known as amylopectin. The linear, short chain sections of the amylopectin molecule which are connected to the longer backbone are sometimes referred to as terminal amylose groups and generally are composed of about 10 to 50 anhydroglucose units.
Starch occurs naturally in plants in the form of granules having an average size of about 5 to 100 microns and containing thousands of individual starch molecules bound tightly together. Unmodified starch granules are insoluble in cold water, but can be dissolved by heating at a temperature of about 70.degree. to 90.degree. C. at atmospheric pressure, at which point the granules gradually swell and rupture and the individual molecules pass into solution. This process by which starch granules swell and rupture is alternatively referred to as gelatinization, pasting, or cooking.
The major commercial source of starch is corn (also known as maize), but potatoes, wheat, barley, rice, and tapioca are also important sources. The relative amounts of amylopectin (branched chains) and amylose (straight chains), as well as the average number of anhydroglucose units in a molecule (commonly known as the Degree of Polymerization, or D.P.) varies with the species of plant. For example, common dent corn starch contains about 72 percent amylopectin and 28 percent amylose; waxy maize corn starch contains nearly 100 percent amylopectin; and a common high amylose corn starch contains about 45 percent amylopectin and 55 percent amylose. Corn starch amylopectin has a D. P. of about 300,000 to 3,000,000 while amylose has a D. P. of about 800 to 8,000.
Corn starch is often modified chemically to alter its physical properties for a given application. One common modification is to substitute other chemical groups onto the hydroxyl groups of the starch molecules. The amount of substitution is expressed as the Degree of Substitution, or D.S. A starch molecule having one substituted group per anhydroglucose unit is defined as having a D.S. of one. A molecule having one substituent per 2 anhydroglucose units has a D.S. of 0.5., and so on. Another common modification is to treat the starch with an agent such as acid or enzyme to cleave some of the bonds between the anhydroglucose units and thereby reduce the average D. P. of the starch molecules. Starches having a reduced D. P. are said to be hydrolyzed or converted. They are often described in terms of their Dextrose Equivalent, or D. E., which is defined for an individual molecule as 100 / D. P. Accordingly, the monosaccharide dextrose, also known as glucose, has a D. P. of 1 and a D. E. of 100. Dextrose Equivalent is a convenient measure of the sweetness of a starch derivative and is widely used in the corn refining industry. In a mixture of molecules having different D.P.'s, D.E. can be viewed as a non-weighted average of the D.E.'s of the individual molecules. Depending upon the population distribution, two mixtures having the same average D.P. can have different D.E.'s, as shown by the following example.
Assume mixture A contains 6 starch derivative molecules, each one having a D.P. of 2 and a D.E. of 50. The average D.P. of the mixture is, of course, 2 (2+2+2+2+2+2/6) and the D.E. of the mixture is 50 (50+50+50+50+50+50/6). Now consider mixture B which also contains 6 molecules, but of the following distribution: The first molecule has a D.P. of 4 and a D.E. of 25; The second molecule has a D.P. of 3 and a D.E. of 33.33; The third molecule has a D.P. of 2 and a D.E. of 50; and the remaining three molecules each has a D.P. of 1 and a D.E. of 100. This mixture has an average D.P. of 2 (4+3+2+1+1+1/6), the same as mixture A. But mixture B has a D.E. of 68 (25+33.33+50+100+100+100/6).
As previously mentioned, a number of starch derivatives have been disclosed as fat replacements. One class of starch derivatives are those which are granular and converted in a non-alcohol process. Chiou et al., European Pat. Appln. No. 91-301368.6, published Aug. 28, 1991, which is incorporated by reference, discloses a granular starch hydrolysate prepared by heating starch in a strongly acidic, aqueous, non-alcohol slurry at a temperature below the gelatinization temperature. The resulting hydrolysate exhibits an unchanged ratio of 1,6- to 1,4- linkages, indicating that the conversion process cleaves the two types of linkages equally. The preferred starch hydrolysate has a D.E. of about 5.0 to 7.0 and an average molecular weight of about 4500 to 5000. These figures indicate that this hydrolysate contains a relatively high amount of low D.P. (<20) molecules. This hydrolysate is sold as a fat replacement under the trademark STELLAR by the A. E. Staley Manufacturing Company. The method of preparation disclosed by Chiou et al. is related to the well known Lintnerization process.
A second class of starch derivatives are those which are granular, alcohol-processed, but not converted. Eastman et al., U.S. Pat. No. 4,465,702, issued Aug. 14, 1984, discloses a nonbirefringent, cold-water-swelling, granular starch material prepared by subjecting ungelatinized starch, in a slurry in selected aqueous alcohols, to conditions of high temperature and pressure. The process does not significantly affect the D.P. of the starch molecules. This starch material is a component of the ready-to-spread cake frosting disclosed in Augustine et al., U.S. Pat. No. 4,761,292, issued Aug. 2, 1988. Augustine et al. state that the starch is believed to play a role in imparting a desirable consistency to the frosting even at relatively low fat levels.
A third class of derivatives taught as fat replacements are pregelatinized (nongranular) starches. Furcsik et al., International Pat. Appln. No. PCT/US90/04013, published Feb. 7, 1991, discloses gelatinized starch derivatives having a D.E. of 5 to 15 derived from high amylose starch which exhibit relatively high gel strengths and can be used as fat replacements. Zallie et al., U.S. Pat. No. 4,937,091, issued Jun. 26, 1990, and Chiu, U.S. Pat. No. 4,971,723, issued Nov. 20, 1990, disclose pregelatinized starch derivatives which are used to lend fat-like textures to aqueous dispersions, such as replacements for caseinate in imitation cheese. The derivatives are debranched using an enzyme, such as Pullulanase, which cleaves the 1,6- linkages in amylopectin. The preferred derivatives comprise about 80% short chain amylose and 20% partially debranched amylopectin. The use of enzymes to reduce D.P. suffers from several disadvantages. First, the process is slow. Second, biological contamination is possible. And third, the enzyme cannot act on granular starch so the process works only with pregelatinized starch.
A fourth class of starch derivatives are dextrins. Lenchin et al., U.S. Pat. No. 4,510,166, issued Apr. 9, 1985, discloses the use of tapioca dextrins having a D.E. of less than about 1.5 as fat replacements in certain foods. These dextrins retain their granular structure, but contain molecules randomly shortened by the conversion process.
A fifth class of starch derivatives worthy of mention are those which are aqueous-alcohol processed, even though they are not disclosed as fat replacements. Battists, U.S. Pat. No. 3,351,489, issued Nov. 7, 1965, discloses stable amylose dispersions prepared by heating amylose starch in boiling acidic liquid mediums containing water or other liquids such as sugar solutions, polyols, and alcohols. Exposure to these conditions gelatinizes the starch. Battista teaches that these dispersions are useful as bases for cosmetics and pharmaceutical preparations, foods, and packaging films, but does not mention their use as fat replacements. A process for producing granular dextrins is disclosed in Sugimoto, U.S. Pat. No. 3,799,805, issued Mar. 26, 1974, which is incorporated by reference. The dextrins are prepared by heating granular starch with acid in an aqueous solution of an organic solvent such as propanol, ethanol, methanol, acetone, and fatty acids. Sugimoto teaches that the resulting dextrins are useful in the production of maltodextrins, but contains no suggestion regarding their use as fat replacements. Another type of aqueous alcohol-treated starch is disclosed in Eastman, U.S. Pat. No. 4,837,314, issued Jun. 6, 1989. These starches are highly derivatized prior to alcohol treatment and are used as replacements for gum arabic.
Despite all the attempts to provide a versatile fat replacement from starch, none has heretofore been discovered and the search continues throughout the food industry.


A system and method for providing group communication services is disclosed. Each of a plurality of group communication devices coverts media, such as video, audio, image and/or data into data packets suitable for transmission over a data network, such as the Internet. The data packets are selectively transmitted through the data network to a communications manager. The communications manager acts as a configurable switch, allowing communications from any communication device to be selectively routed to the plurality of communication devices based on the types of the communication devices and/or the requests received from the corresponding users. The communications manager further allows users of other communication systems and devices to participate in group communications with each other.

Point-to-multipoint communication systems provide communications generally between a central location and multiple users of the system. For example, dispatch systems using Land Mobile Radios (LMRs) have been used in trucks, taxis, buses, and other vehicles in order to communicate scheduling information between a central dispatch center and one or more corresponding fleet vehicles. Communications may be directed at a specific vehicle in the fleet or to all vehicles simultaneously.
A class of wireless services intended for quick, efficient, one-to-one or one-to-many (group) communication operates in half-duplex communication, using a forward link or a reverse link at a time. A user presses a "push-to-talk" (PTT) button on a phone/radio to initiate a group communication. If granted the floor, the user provides media for a short time period. After the user releases the PTT button, other users may request the floor. These services have traditionally been used in applications where one person, a "dispatcher," needs to communicate with a group of people, such as field service personnel or taxi drivers. Similar services have been offered on the Internet and are generally known as "voice chat."
A key feature of these services is that communication is quick and spontaneous, usually initiated by simply pressing a PTT button, without going through a typical dialing and ringing sequence. Communication in this type of service is generally very short, with individual media "spurts" being generally on the order of several seconds, and "communications" lasting possibly a minute or less. The time delay between when the user requests the floor and when the user receives a positive or negative confirmation from a communication manager, indicating that the user has the floor and may begin providing media, is known as PTT latency.
PTT half-duplex communication offers a number of advantages, such as improved bandwidth efficiency, reduced sensitivity to latency, and simplified echo cancellation.
There is a need, therefore, for concurrent communication of multimedia, e.g., audio, video, image and/or data, in half duplex mode, which provides the advantages of PTT group communication services.

Communication device for providing multimedia in a group communication network


The invention provides methods, kits, and compositions comprising novel mutant loxP sites. Such sites are particularly useful for procedures requiring multiple site-specific recombination reactions, including deletions or insertions of multiple genes or other sequences in the same organism, staged insertions or deletions of genes of the same organism at different times, assembly of large polynucleotide constructs by serial site-specific recombination, and the like. In one aspect, compositions of the invention includes particular mutant spacer oligonucleotides of loxP recombination elements, the recombination elements themselves, and pairs of non-promiscuous mutant loxP sites.

Cre-loxP recombination is an important tool in molecular genetics. Cre ("Causes recombination") recombinase from bacteriophage P1 recognizes a specific 34 basepair (bp) target sequence, termed loxP, composed of an 8 bp spacer region flanked by two identical 13 bp inverted repeats (Table 1), e.g. Hoess et al Proc. Natl. Acad. Sci., 79: 3390-3402 (1982). Each base in the spacer region is conventionally named 1, 2, 3, 4, 5, 6, 7, or 8, according to its order (5′→3′) in the sequence. Cre-loxP sites mediate site specific intra- or inter-strand exchange of DNA molecules catalyzed by Cre recombinase. Depending on the location and the orientation of these sites, they can invert, insert, delete or exchange fragments of DNA in prokaryotic or eukaryotic systems, e.g. Sauer, Mol. Cell. Biol., 7: 2087-2096 (1987); Sauer et al, Proc. Natl. Acad. Sci., 85: 5166-5170 (1988); Sauer et al, Nucleic Acids Research, 17: 147-161 (1989). Orientation of insert DNA post-recombination is dependent on the orientation of the sites prior to the reaction, with sites in the same orientation on a given DNA strand mediating excision of intervening sequence and sites in opposite orientation mediating inversion of intervening sequence. Since the excision reaction is kinetically favored over the insertion reaction, gene deletion/inactivation experiments are straightforward to engineer by flanking the target sequence with loxP sites. The difficulty in implementing a stable DNA insertion is that the insertion reaction results in the presence of two loxP sites in cis configuration in the post-recombination product, which themselves become substrates for Cre and lead to rapid excision of the inserted component polynucleotide.
Two classes of variant loxP sites are available to engineer stable Cre-loxP integrative recombination. Both exploit sequence mutations in the Cre recognition sequence, either within the 8 bp spacer region or the 13-bp inverted repeats. Spacer mutants such as lox511, lox5171, lox2272, m2, m3, m7, and m11 recombine readily with themselves but have a markedly reduced rate of recombination with the wild-type site, e.g. Hoess et al, Nucleic Acids Research, 14: 2287-2300 (1986); Lee et al, Gene, 216: 55-65 (1998); Langer et al, Nucleic Acids Research, 30: 3067-3077 (2002). This class of mutants has been exploited for DNA insertion by Recombinase Mediated Cassette Exchange (RMCE), e.g. Seibler et al, Biochemistry, 36: 1740-1747 (1997); Schlake et al, Biochemistry, 33: 12746-12751 (1994); Baer et al, Curr. Opin. Biotech., 12: 473-480 (2001). Inverted repeat mutants represent the second class available and contain altered bases in the left inverted repeat (LE mutant) or the right inverted repeat (RE mutant). The LE mutant, lox71, has 5 bp on the 5′ end of the left inverted repeat that are changed from the wild type sequence to TACCG, e.g. Albert et al, Plant J., 7: 649-659 (1995); Araki et al, Nucleic Acids Research, 25: 868-872 (1997). Similarly, the RE mutant, lox66, has the five 3′-most bases changed to CGGTA. Inverted repeat mutants are used for integrating plasmid inserts into chromosomal DNA with the LE mutant designated as the "target" chromosomal loxP site into which the "donor" RE mutant recombines. Post-recombination, loxP sites are located in cis, flanking the inserted component polynucleotide. The mechanism of recombination is such that post-recombination one loxP site is a double mutant (containing both the LE and RE inverted repeat mutations) and the other is wild type, e.g. Van Duyne et al, Annu. Rev. Biophys. Biomol. Struct., 30: 87-104 (2001); Lee et al, Prog. Nucleic Acid Res. Mol. Biol., 80: 1-42 (2005); Lee et al, J. Mol. Biol., 326: 397-412 (2003). The double mutant is sufficiently different from the wild-type site that it is unrecognized by Cre recombinase and the inserted component polynucleotide is not excised. Recently, spacer and inverted repeat mutants have been combined to increase the specificity and stability of integrative recombination, e.g. Langer et al (cited above); Araki et al, Nucleic Acids Research, 30: e103 (2002).
Previously, novel spacer mutants have been discovered by mutating bases or by generating a set of potential spacer mutants and testing recombination between these spacers with the wild-type loxP site, e.g. Langer et al (cited above); Lee et al (Gene, cited above). In particular, Lee et al used an in vitro assay that evaluated the recombination efficiency of 24 spacers with 1 bp substitutions and 30 spacers with 2 bp substitutions from the sequence of the wild-type loxP. Their data suggested that homology was required at positions 2-5 and positions 6-7 for efficient strand exchange and resolution of a Holiday junction, whereas positions 1 and 8 had relaxed homology requirements. They concluded that homology was essential to achieve recombination rates between mutant loxP spacers comparable to that of the wild-type sequence. Their success with the lox2272 mutant suggested that positions 2 and 7 were particularly important in blocking promiscuous recombination.
The above work is important because recombination systems, such Cre-loxP and others, provide a means for making and/or manipulating large polynucleotide constructs that are useful in fields, such as synthetic biology, metabolic engineering, and the like, where practitioners seek to improve cellular activities by large-scale manipulation of enzymatic, transport, and regulatory functions of cells, e.g. Bailey, Science, 252: 1668-1674 (1991). It would be highly useful to such fields if there were available additional recombination elements that could be used together without cross-reactivity for the purpose of constructing large polynucleotide constructs, particularly through successive cycles of site-specific recombination.

This patent is subject to a terminal disclaimer.

Kits for multiple non-cross reacting recombination reactions utilizing loxP sequences


The present invention relates to a device and a method for dividing up substrates (2) in wafer form (e.g. wafers), which is used in the semiconductor industry, MST (microstructure technology) industry and photovoltaic industry, whereby improved reliability of the process and lower reject rates are accomplished. This object is achieved according to the invention by using adhesion forces that act between the substrates in wafer form and the devices (1) thereby used.

Disk-shaped substrates (for example, so-called wafers) from semiconductor material, which are manufactured, among other things, from polycrystalline and monocrystalline silicon, are needed for the semiconductor, MST (microstructure technology) and photovoltaic industries for manufacturing products of these branches of industry.
To obtain these disk-shaped substrates, blocks or cylinders of these semiconductor materials are cut into disk-shaped substrates by means of wire saws. This is carried out by a cutting process, during which this wire (thickness 200 μm) is pulled in a plurality of windings in parallel through the block or cylinder by means of an abrasive, which is in a so-called slurry. Wafer thicknesses of 270 μm to 320 μm are thus obtained currently. The blocks or cylinders cut into wafers are cleaned after this cutting in a cleaning step to remove the slurry. Since the need for high-purity silicon has increased greatly worldwide, because the manufacturers of wafers are currently unable to deliver sufficient quantities of wafers for the photovoltaic industry, it is necessary that the wafer thicknesses be reduced, especially for this field of application, in order to obtain a larger number of wafers from one block or cylinder. Wafer thicknesses of less than 130 μm are desirable. The separation of such disk-shaped substrates is currently embodied by mechanical gripping or pushing mechanisms, which act on the edges of the wafer and thus lead to an increased percentage of broken wafers. Such a process is described in European Patent EP 0 802 028 A2. The individual wafers are cut off there and brought to the receiving device by means of a conveyor belt.
Another method of separating wafers is described in German Patent DE 199 00 671 A1. The individual wafers are separated from each other in this process by blowing in fluid streams. This kind of separation might be suitable for wafers of standard thicknesses.
The small thicknesses of less than 130 ρm make the wafers, which are already highly susceptible to breakage, even more sensitive to mechanical loads, so that wafer separation processes, which apply compressive, tensile or shearing forces on the wafers, must be avoided as much as possible. This also forbids separation by hand, because this handling also leads to great losses of wafers due to breakage and leads, moreover, to a greatly reduced reproducibility.
It is therefore necessary because of the highly complicated and sensitive handling to automate separation processes as much as possible.

Process for separating disk-shaped substrates with the use of adhesive powers