A feedback control circuit and method for a control system used to control an electrical power generating source that comprises a free piston Stirling engine driving a linear alternator. A switching mode rectifier connects the alternator winding to an output circuit that includes an electrical energy storage means and is controlled by a pulse width modulator that controls the rectifier switching duty cycle and phase. The control system controls the pulse width modulator. The improvement computes a voltage across a virtual tuning capacitor and uses the computed voltage to control the switching mode rectifier so that the switching mode rectifier is switched in a manner that makes the alternator circuit operate as if a tuning capacitor were actually present and so that the control system controls the piston of the Stirling engine to maintain balance of the mechanical power generated by the Stirling engine and the electrical power absorbed from the engine by the alternator.

1. Field of the Invention
This invention relates generally to a free-piston Stirling engine driving a linear alternator to generate electrical power and more particularly relates to improvements in a closed loop, negative feedback control system for such an electrical power generating source.
2. Description of the Related Art
This invention is directed to an improvement in a control system for controlling a free-piston Stirling engine driving a linear alternator for converting heat energy to electrical power. The improvements include a novel control loop for controlling piston stroke to maintain the mechanical power generated by the engine equal to the power transferred from the engine to the linear alternator and also include a control loop for controlling another variable, such as DC output voltage or head temperature. Embodiments of the invention may also be applied to control multiple such engine/alternator pairs and maintain them in synchronization.
Control Circuits
As known to those skilled in the control system art, a closed loop, negative feedback control system has a forward loop and at least one feedback loop. The forward loop has a command input that is applied to a summing point (or summing junction). The command input is a signal representing a desired (commanded) value of an operating output variable parameter that is being controlled and provides a reference signal.
The forward loop also has at least one and may have a series of forward control elements (also known as "dynamic units") that perform a mathematical operation on a signal that passes along the forward loop. Each forward control element has a forward transfer function which is a mathematical expression relating its input signal to its output signal.
A feedback loop of a closed loop, negative feedback control system has a sensor for measuring the actual value of the variable parameter that is being controlled and applies a signal representing that actual value to the summing point. The feedback loop may also perform one or more mathematical operations on the measured signal, such as scaling, before applying it to the summing point. The output of the summing point provides an error signal representing the difference between the desired value and the measured value of the controlled parameter. That error signal is applied to a forward control element.
Closed loop, negative feedback control systems are not limited to a single feedback loop, a single summing point or a single forward control element. A closed loop control system may have multiple summing points interposed between multiple forward control elements that are connected in series along the forward loop. Multiple feedback loops, each sensing and feeding back a signal representing a different sensed variable parameter, are connected to these summing points. Consequently, each summing point has an input representing a command input, an input representing a feedback signal that represents a sensed variable parameter and an output representing a difference between the inputs to the summing point. Each summing point also might have inputs representing disturbances or external force or torque loads, for example. Although the difference often represents the difference (an "error") between a commanded value of an output variable and a sensed value of the same variable, the difference can also be simply a modification of one signal by another signal described mathematically. There are also other types of circuit connections, such as a feed forward loop. Elements of a control circuit are conventionally represented in a control circuit diagram as mathematical expressions for the operations they perform on their input signals. The mathematical expressions are advantageously Laplace transform expressions and tell an engineer skilled in the art the operating characteristics of the elements in the control system and therefore how to construct hardware implementations of them. Ordinarily, there are multiple computing circuits known to those skilled in the art to implement each element in the control system so long as they perform the transfer function described by their mathematical expressions.
Persons skilled in the control system art also recognize that such control systems can be implemented with analog or digital computing circuits and combinations of them. The mathematical operations described in the diagram of a control system are desirably implemented with any of a variety of commercially available microprocessors, microcontrollers or other computing circuits. As known in the current state of the art, analog circuit and mathematical operations can be economically performed by software programmed digital circuits having software algorithms that simulate analog circuit operations and perform or compute mathematical operations. Many of these operations can be performed by discrete logic, programmable logic array (PLA), programmable gate array (PGA) or digital signal processor (DSP) implementations, as well as by microprocessors or microcontrollers. Therefore, the terms "control circuit" and "controller circuit" generically include the known types of analog and digital logic control implementations that can be used to implement the control circuit illustrated on a control circuit diagram. The term "computing circuit" refers to circuit implementations utilizing such circuits for transforming an electrical signal in accordance with a mathematical operation or algorithm.
Free-Piston Stirling Engines and Alternators
A free-piston Stirling engine (FPSE) driving a linear alternator is an attractive electrical power source because such sources are efficient, compact and light weight and can generate electrical power from heat energy supplied by a variety of fuels. A free-piston Stirling engine is a closed-cycle, reversible heat engine which converts heat into work by moving a confined volume of working gas between a relatively warmer heat acceptor and a relatively cooler heat rejector. The resulting alternating, cyclical, expansion and compression of the internal working gas provides an oscillating pressure wave that drives an appropriately sprung piston to oscillate substantially sinusoidally in linear reciprocation. The piston is mechanically linked to a ring of permanent magnets that it drives in reciprocation within the winding or coil of the linear alternator thereby inducing a voltage across the winding terminals. Typically, the piston of the engine is directly linked by a flange on the back of the piston to an array of axisymmetrically arranged magnets, for example arranged in a ring, and the engine and alternator are integrated into a common, hermetically sealed housing.
Many prior art electrical power sources of this type include a rectifier circuit connecting the alternator output terminals to an electrical load and also have a controller which is a control system for controlling the operating parameters of the Stirling engine and the alternator as well as the output electrical parameters. The operation of a free-piston Stirling engine and its connection to a linear alternator are described in many publications, including patents such as U.S. Pat. No. 6,871,495 which is herein incorporated by reference.
Energy for driving the FPSE is supplied from an external heat source, such as fuel combustion, solar energy or heat from radioisotope power sources, applying heat to the engine heat acceptor ("hot end"). The heat energy is converted by the engine to mechanical work energy which drives the linear alternator to convert the mechanical energy to electrical energy. It is highly desirable that the mechanical power generated by the FPSE be exactly equal to the power transferred from the FPSE to the linear alternator, most of which is ultimately transferred to the load. This balanced power condition avoids significant problems with engine operation. If the power transferred to the alternator exceeds the power generated by the FPSE, the engine will stall. If the power transferred to the alternator is less than the power generated by the FPSE, the piston stroke will increase uncontrollably and can cause damaging internal collisions and engine temperature will slowly increase over time. Piston stroke is the distance traveled by the piston between the boundaries of its reciprocation. Piston motion as a function of time can be represented as a phasor with a piston amplitude XP and is sometimes alternatively used to describe piston displacement. Piston amplitude XP has a magnitude of one half piston stroke and the two terms are sometimes used interchangeably when describing qualitative aspects of operation.
Fuel combustion systems for electrical power generating systems of this type commonly have temperature control systems that control the temperature at the engine's heat acceptor. Consequently, for relatively long term control, the mechanical power delivered from the engine to the alternator can be modulated by increasing or decreasing the thermal input power to the engine head which causes its temperature to change. However, that is an insufficient control for at least two reasons. First, the rate of temperature change that can be accomplished is relatively slow, far too slow to respond in time to prevent either engine stalling or piston over-stroking. Second, engine efficiency is strongly dependent upon heat acceptor temperature. The hotter the heat acceptor temperature at the engine head, the more efficient the engine. Therefore, modulating thermal input power and temperature not only is too slow but also reduces engine efficiency because it does not maintain the highest possible input head temperature. It is therefore desirable to provide a way to control engine output power in order to maintain the power transfer balance between the engine and the alternator, but it is desirable to do so in a way that permits the hot end temperature of the FPSE to remain at a constant maximum temperature in order to maximize engine efficiency. Although embodiments of the invention advantageously include a fuel combustion control system that maintains a constant temperature that is as hot as the engine materials can withstand, that alone is not a viable option for controlling engine power output and piston stroke and maintaining the power balance described above.
Prior Art Examples
FIG. 1 is a simplified schematic diagram illustrating the electrical circuit of a prior art electrical power generating source having a linear alternator 10 driven by a free-piston Stirling engine and applying the alternator AC output to a load 12. The alternator is shown as its equivalent, lumped-element circuit. This equivalent circuit has, in series connection, an inductor 14 having inductance Lalt representing alternator winding inductance, a lumped resistance Rac representing alternator resistance and an AC voltage source 16 having an induced or back emf Vg. The voltage Vg is the open circuit voltage induced in the alternator winding by the magnets that are driven in reciprocation by the free-piston Stirling engine.
A tuning capacitor 18 is frequently connected in series with the alternator winding in order to tune out the winding inductance. The capacitance of the tuning capacitor is chosen so that, at the operating frequency of the alternator and engine, the inductive reactance of the winding and the capacitive reactance of the tuning capacitor form a series resonant circuit. Such series resonant circuits exhibit a zero or resistive impedance. The tuning capacitor consequently provides a unity or near unity power factor which maximizes power transfer from the alternator to the electrical load and minimizes resistive heat losses. However, such tuning capacitors are bulky and expensive so it is desirable to eliminate the tuning capacitor. Also, the tuning capacitor impedance and the series inductor impedance only match at a single frequency. Therefore, with a tuning capacitor, the output power factor varies with engine operating frequency. The controller of the present invention can compensate over a wide range of frequencies, provide unity power factor or constant frequency operation.
As also illustrated in FIG. 1, the output of the alternator can be connected to the utility electrical power grid 20 and used to supply electrical power to the grid. As known to those skilled in the prior art, if a tuning capacitor 18 is used to balance or cancel the inductive reactance of the alternator winding, this arrangement results in the free-piston Stirling engine operating at the same frequency and substantially in phase with the electrical grid. This synchronous operation occurs because the Stirling engine is coupled to the alternator by the magnetic coupling between the reciprocating permanent magnets and the alternator winding. The coupling of the magnetic flux of the reciprocating magnets with the magnetic flux resulting from the alternator current, causes the alternator current to be reflected into the engine as complex damping forces acting upon the free-piston Stirling engine. These forces, which are reflected back into the engine, act upon the piston of the engine as a combination of mass, spring and damping forces. If a tuning capacitor is used, the magnetic force generated by the alternator current acts upon the Stirling engine piston to cause the piston to run synchronously with the alternator current in the same way that a rotating synchronous electric motor, having two rotating magnetic fields, remains synchronous. If the magnetic field from the reciprocating magnets becomes advanced or retarded from the magnetic field from the alternator current, there is a magnetic force pulling them together. In the linearly reciprocating engine and alternator, the result is that the reciprocating piston of the FPSE will operate synchronously with the electrical power grid voltage, if the FPSE is designed to be mechanically resonant at or very near the power grid frequency and the capacitor is tuned for series resonance with the alternator winding.
FIG. 2 illustrates an electrical power generating source like that of FIG. 1 and known in the prior art, but having a common, passive, full wave rectifier 22 using four diodes arranged in an H-bridge to provide a DC output. The prior art has also substituted a full wave, switching mode rectifier, also known as an active rectifier, for the full wave diode rectifier of FIG. 2 and eliminated the tuning capacitor 24 by various techniques. An example of such a configuration is shown in the above cited U.S. Pat. No. 6,871,495.
Switching Mode Rectifiers
A switching mode rectifier is a type of circuit that is known in the prior art and described in multiple publications. It typically has an H-bridge configuration but has controllable electronic switches, commonly MOSFETs, substituted for the diodes of FIG. 2. An active rectifier controller or control circuit is connected to the gate of each electronic switch and switches them ON and OFF by switching one diagonally opposite pair ON and the other pair OFF and alternating the pair that is ON while the other pair is OFF. This switching is done at a frequency that is much higher than the sinusoidal frequency of the FPSE and alternator. For example, the electronic switches may be switched at a rate of 10 kHz or 20 kHz while the FPSE and alternator may be operated at 60 Hz or 120 Hz. The switching control not only turns the electronic switches ON and OFF as described, but also varies the duty cycle of the electronic switches in response to a modulating input signal. The switching control of a switching mode rectifier is essentially a pulse width modulator that includes a high frequency oscillator for alternately switching the diagonally opposite switch pairs and also modulates the duty cycle of the ON and OFF switching states that are switched at the high frequency. The phase of the switching is a function of the phase of the signal that control the pulse width modulator and the duty cycle of the switch pairs is a function of the amplitude of that control signal. As a result, the phase of the switching of the switching mode rectifier controls the phase of the current though the H-bridge relative to the alternator terminal voltage. However, because the phase control by the switching mode rectifier does not depend upon resonance, which is frequency dependent, a switching mode rectifier can maintain a desired phase relationship over a range of engine operating frequencies. The pulse width modulating circuit and function can be implemented not only with analog circuits but also and more importantly using microprocessors or microcontrollers, as is preferred, and other digital logic and processing circuits that are programmed, such as with software, to perform the pulse width modulating function. Because switching mode rectifiers, summarized above, are described in prior art text books and technical literature about switch mode power supplies, switch mode inverters or switch mode motor drives, switching mode rectifiers are not explained here in more detail.
Variations
FIG. 1 also illustrates the use of a "dump" resistance 26 as another prior art way of controlling piston stroke and maintaining the power balance between the engine and the alternator. The resistance 26 is an additional electrical load that can be switched into the circuit or varied in resistance to essentially waste excess power produced by the engine. However, this is obviously undesirable because it simply dissipates excess power produced by the engine in order to maintain the power balance and consequently reduces efficiency by wasting heat energy and therefore wasting fuel.
The prior art has recognized that the power out from a FPSE can be controlled by controlling piston stroke because the power produced by a FPSE is approximately proportional to the square of the piston stroke. However, the voltage induced in the alternator is proportional to stroke and most electrical loads require a stable, constant voltage, such as 24 vdc or 28 vdc or 115 vac. Consequently, it is a problem to design a control system that accomplishes both (1) matching the power delivered to the alternator by the FPSE to the power demanded by the electrical load plus electrical losses; and (2) maintaining a constant output voltage. The problem is that, if the electrical power demand of the electrical load decreases and the stroke is decreased to reduce FPSE power, the induced voltage drops. Conversely, if an increased electrical power demand results in an increased stroke to provide more power from the FPSE, the output voltage also increases. It is therefore desirable to modulate the power from the FPSE to match electrical load power while reducing or eliminating voltage variations at the electrical load that result from variations in load power demand.
Additionally, there is a need for a manner of controlling piston stroke by a feedback control system that can more quickly detect variations in operating parameters resulting from system disturbances that lead to unwanted variations in piston stroke and that can quickly respond to the detected variations so that the actual piston stroke is maintained within tighter boundaries.
Similarly, there is a need for a manner of controlling piston stroke that can quickly vary the piston stroke in response to changes in the electrical power out load demand and maintain the balance of Stirling engine generated power out and power absorbed by the alternator.
Therefore, it is an object and feature of the present invention to provide an improved way of controlling piston stroke in order to match mechanical power produced by the engine to mechanical power absorbed from the engine by the alternator which is essentially the electrical power required by the user load.
A further object and feature of the invention is to control piston stroke based upon an operational parameter that can be more easily and more quickly controlled thereby permitting control of piston stroke, and therefore of power balance, within closer tolerances.
A further object and feature of the invention is to combine the piston stroke control with circuitry and a feedback control loop to provide improved voltage regulation so that the FPSE can be operated over a wide range of piston stroke for maintaining the balance of the engine power transferred to the alternator and yet still provide a relatively constant, well regulated output voltage to the electrical load over a wide range of load power consumption.
Yet another object and feature of the invention is to provide an even simpler, more stable and more effective controller for controlling an electrical power generating source comprising a free piston Stirling engine driving a linear alternator than previously disclosed.

Controller computing a virtual tuning capacitor for controlling a free-piston stirling engine driving a linear alternator


A method for decoding data from multiple channels by predicting future symbol periods is disclosed. The method includes the steps of receiving data symbols on two channels, detecting data symbol level transitions for each channel, predicting a future symbol level transition, verifying the validity of data symbols on each channel, and selecting the best data symbol from one of the two channels.

1. Field of the Invention
The present invention relates to communication receivers. More specifically, the present invention is directed to multi-channel predictive decoding in a communication receiver.
2. Description of the Prior Art
Radio frequency ("RF") homodyne receivers are used in RF identification ("RFID") systems. RFID systems may be used, for example, to identify a vehicle passing through a toll lane to charge a toll fee to a corresponding account.
In addition to the receiver, an RFID system includes an RF source and a transponder tag associated with a target to be identified (e.g., a vehicle). The source transmits an RF signal that reaches the tag. The tag backscatter-modulates the signal, which is then received by the RF homodyne receiver. Backscatter modulation may be defined as the alteration of a tag's radar cross section with time.
The RF homodyne receiver mixes the backscattered signal with a local oscillator ("LO") signal to produce intermediate frequency ("IF") signals. The IF signals are then amplified and decoded to obtain identification data.
One of the major problems encountered with RFID systems is that to produce a measurable IF signal, the backscattered signal should preferably be in phase with the LO signal. Mathematically, if the LO and the RF signals received are cosine waves, the signals mix (e.g., are multiplied with each other) and can be expressed as a square cosine IF signal. But if the received RF signal is 90 degrees out of phase with the LO signal, the resulting signal is a cosine multiplied by a sine, which results in an IF signal having zero magnitude.
A first solution to the problem involves three-channel phase detection. In this approach, three different phases of the backscattered signal mix with the LO signal to produce IF signals. The receiver amplifies, filters, and digitizes the IF signals. The digitized IF signals are then sent to a decoder where information is extracted by selecting the two channels that have the same decoded data. The major problem with a two-channel decoder is trying to decide which of the two channels is correct. With the three-channel decoder only one channel can be out of phase at a time, and when two out of the three channels (phases) being received are in agreement, the correct data can be deciphered. The three-channel decoder however requires filtering and amplification of three independent channels, which takes up receiver space. In addition, the reception depends on the least sensitive of the two selected channels.
A second solution to the in-phase problem is similar to the three-channel phase detection approach discussed above. The difference lies in the use of a quasi-third channel. RF mixing occurs at four phase angles: 0 degrees (A+), 90 degrees (B+), 180 degrees (A−), and 270 degrees (B−). A channel "A" is processed as (A+)-(A−); a channel B is processed as (B+)-(B−); and the quasi-third channel is processed as (A+)-(B−). The quasi-third channel approach requires processing of three channels and two-out-of-three voting, which results in a significant decrease in the signal-to-noise ratio.
A third solution to the in-phase problem, which may be used with only two channels, is to correlate known symbols of choice with symbols received on each of two channels 90 degrees apart. The channel with the greatest correlation to a known symbol is then selected for decoding. Correlation works well when the exact periods of the incoming data symbols are known.
In RFID systems the tags are designed for low cost, and therefore, the period of the received symbols can vary by as much as 20%.
Not knowing the period (or length) of the incoming signal makes it very difficult to determine the period (or length) of the incoming signal utilizing correlation. This task becomes even more difficult when trying to choose between two channels.
A fourth approach for solving the in-phase problem is to distinguish a bad channel from a good one by selecting the signal with the greatest power. This is the technique normally utilized in sampled systems. For systems where amplitude information has been reduced to either ON or OFF, state power measurements are not available. This invention provides an advantage in systems where only binary transitions and their occurrence in time are available, including cases where the power levels of two incoming signals are not known.
The present invention as described in the sections that follow provides solutions to the problems discussed above.


An electrical lead for implantation in a patient comprises separate first and second lead portions having conductor wire therein. The leads are electrically connected at respective ends within a lead anchor member. In accordance with this invention, the lead anchor has means for fixed retention of the first and second lead portions in electrical connection therewith so that an electrical signal passing through the lead passes through a conductive portion of the lead anchor between the first and second lead portions. The lead anchor has means permitting suture retention in a desired implanted position in the patient.

This application relates to electrical leads which are intended for implantation in the patient for numerous uses such as cardiac pacing or sensing, or any other desired use. Particularly, the lead of this invention is contemplated for use as part of a spinal lead system, in which, as is conventionally known, electrical current is applied to the spinal cord as a method of alleviating lower back pain. Such a lead is used to place an electrode in the epidural space of the spine. The lead may be adjusted in its position with current applied on an experimental basis until the patient reports the best paresthesia in a given position. At that point, or at a later time, the surgeon may implant, subcutaneously, a neurostimulator, and connect it to the positioned lead for transferring neurostimulating signals to the spinal cord.
In the prior art, a separate lead anchor is generally affixed in the area of the spinal lead's exit from the spinal column, and sutured to the patient. The purpose of this is, of course, to maintain the optimum position of the lead in the spinal column for maximum pain surpressing effect. The anchor may typically be sutured to the underlying muscle, with sutures also tied around the body of the anchor, while the lead itself is positioned within the anchor in telescoping relation thereto for retention.
Unfortunately, it has been found that, as the patient moves, it is possible for the lead to slide to a certain extent with respect to the lead anchor. This, in turn, results in a shifting of the position of the electrode in the epidural space, which may reduce the effectiveness of the pain-reducing electrical stimulation through the electrode. However, this problem has not been easily solved, because the precise positioning of the lead anchor on the lead cannot be exactly determined until actual implantation has taken place and after the electrode on the lead has been precisely positioned. Accordingly, the lead anchor cannot be preattached to the lead in a manner to effect permanent, non-sliding attachment, because of the unpredictability of the positioning of the lead tip and its electrode in the spine, coupled with the requirement for the lead anchor to be positioned at only about one possible position, at the spinal lead's exit from the patient.
For this reason, in the prior art, a lead anchor with a sliding connection with the lead that it retains has been mandatory.
In accordance with this invention, an improved electrical lead is provided, in which an attached lead anchor means may be adjustably positioned with respect to the lead. Nevertheless, the lead anchor cannot slide along the lead, so that an electrical lead may be provided for implantation with adjustable lead anchor positioning, but without the problem of the prior art of migration of the lead within the spine after the implantation procedure is complete. It can be understood that such migration is very unpleasant because it may require another operation to readjust the positioning of the lead, which of course is very traumatic to the patient and highly undesirable.


Systems or methods for losslessly compressing data received from sensors, such as photon counters, are disclosed. An integer representation of a sensor reading is received from a sensor. The integer representation is combined with additional integer representations from each of a plurality of additional sensors into a single integer value. The single integer value is then stored as an element of an integer array that represents a predefined sample interval.

Sensors often generate readings frequently. For example, photon counters may determine thousands or millions of times per second whether or not a photon detector has detected a photon and the number of times the photon detector has detected the photon. The readings can often consume large amounts of data when stored in memory.


Silicon carbide single crystal is prepared. Using the silicon carbide single crystal as a material, a silicon carbide substrate having a first face and a second face located at a side opposite to the first face is formed. In the formation of the silicon carbide substrate, a first processed damage layer and a second processed damage layer are formed at the first face and second face, respectively. The first face is polished such that at least a portion of the first processed damage layer is removed and the surface roughness of the first face becomes less than or equal to 5 nm. At least a portion of the second processed damage layer is removed while maintaining the surface roughness of the second plane greater than or equal to 10 nm.

1. Field of the Invention
The present invention relates to a method of manufacturing a silicon carbide substrate, and a silicon carbide substrate.
2. Description of the Background Art
When the warp of a silicon carbide substrate is too great, inconvenience occurs in manufacturing a semiconductor device using the silicon carbide substrate. Therefore, the level of warping must be regulated. According to U.S. Pat. No. 7,422,634, a value representing the warping of a wafer is represented by "warp" that is the distance between the maximum value and minimum value of the wafer surface measured from a reference plane. This value is set smaller than approximately 0.5 μm. The specification of the cited reference discloses a method of using a double-side lapping device as an exemplary method of manufacturing a wafer. The publication teaches that polishing and etching are preferably carried out subsequent to usage of the double-side lapping device, and that the etching is dispensable.
Assuming that an equivalent damage layer is formed at each of the top face and backside face of the wafer (silicon carbide substrate) subsequent to processing by the double-side lapping device, it is considered that the warp of the silicon carbide substrate may become smaller since the stress at both of the damage layers becomes equivalent. However, the face formed by the lapping device generally has a relatively great surface roughness, not suitable to have an epitaxial layer of high quality formed thereon or a semiconductor element formed therefrom. Therefore, polishing of further accuracy is required after lapping.
If the aforementioned polishing is applied only to the top face (first face) among the top and backside faces, the damage layer at the top face and the damage layer at the backside face will no longer be equivalent since removal of the damage layer will be carried out at only the top face among the top face and backside face. As a result, the warp of the silicon carbide substrate is increased. This may cause inconvenience in manufacturing a semiconductor device. For example, the resolution in photolithography is degraded, or the wafer may be cracked when being fastened.
If the aforementioned polishing is carried out on both the top face and backside face, the surface roughness will be reduced, not only at the top face, but also at the backside face (second face). In other words, both the top face and backside face are mirrored. In other words, the appearance of each of the top face and backside face will become substantially the same. As a result, distinguishing between the top face and backside face will become difficult. Unlike a silicon substrate, the physical property differs between the top face and backside face of a silicon carbide substrate, since two types of planes, i.e. a Si plane and a C plane, are present due to the crystal structure thereof. Therefore, distinguishing between the top face and backside face is important even if the surface roughness is the same. Furthermore, the backside face having a mirrored face induces the problem that, when the backside face of the silicon carbide substrate is mounted on a stage, the backside face will slip on the stage or adhere to the stage.

Silicon carbide substrate manufacturing method and silicon carbide substrate


Receiving a notification message by a mobile subscriber can include establishing a session with a notification service; maintaining a persistent communication connection with the notification service after the session is established; subscribing to a node hosted by the notification service, wherein the node is pre-provisioned for use by a mobile subscriber; and receiving from the notification service a notification message corresponding to the subscribed node. Further, a message can be transmitted over the communication connection to the notification service at a predetermined interval and it can be determined whether the communication connection is viable. Additionally, it can be determined that the communication connection is no longer viable if no response is received from the notification service, the period of the predetermined interval can be decreased, and another session with the notification service can be established.

An entity, such as an application or a device, can be configured to discover that an event of interest has occurred, such as a change in the status of another application or device. Further, the entity can take an appropriate action in response to the occurrence of the event of interest. As a result, the entity can be configured to automatically perform one or more actions in response to a state of an application or a device. For example, the entity can download and install a software patch in response to discovering that the software patch has been made available on an accessible server.
An entity can determine whether an event of interest has occurred by polling a corresponding event provider. For example, a change in the state of the event provider being polled can be interpreted as the occurrence of an event of interest. Through polling, the entity actively transmits one or more requests for information to the event provider. The event provider then responds with the requested information. Further, the polling can be performed periodically, such as at a predetermined interval. Thus, an event of interest can be detected within a predetermined amount of time after occurrence. Polling also can be performed in response to the occurrence of another event.
The occurrence of an event of interest also can be discovered through receipt of a notification message. The notification message can be sent directly from the event provider to the entity to indicate that an event of interest has occurred. In order to receive direct notification, however, the entity must be known to the event provider. Thus, the entity must register with each event provider from which notification messages are desired.
Alternatively, one or more notification messages can be distributed in accordance with a publish-subscribe model. In a publish-subscribe model, an event provider (or "publisher") publishes information to a notification service indicating that an event of interest has occurred. Further, the notification service can generate and transmit a corresponding event notification message to one or more entities (or "subscribers") that have subscribed to receive notification messages associated with the event of interest. In a publish-subscribe model, each of the subscribers registers with the notification service to receive messages corresponding to one or more nodes (or "topics"). Generally, a message associated with the publish-subscribe model can include a payload of data, such as additional data that provides history or contextual information. A notification message, however, can be formatted to omit the payload of data. Thus, a notification message can indicate the occurrence of an event of interest without the additional overhead and processing associated with a typical message in the publish-subscribe model.
A notification service can include multiple nodes (or "topics"), to which one or more publishers can publish information regarding events of interest. Multiple subscribers also can subscribe to notification messages associated with a particular node. Thus, a notification service can broadcast a notification message associated with a single publisher to multiple subscribers. Further, a subscriber can subscribe to event notifications associated with multiple publishers. Additionally, a notification service can be configured to manage access to the notification system by both publishers and subscribers. For example, the notification service can maintain subscription lists, authenticate publishers and subscribers that are requesting to open a session, and manage nodes to which information can be published.
The publish-subscriber model has been implemented to notify subscribers of a variety of events. For example, network accessible content sites, such as news sites and weblogs, commonly implement the publish-subscribe model to notify subscribers of new content. When a new item of content is available on the content site, a publisher associated with the content site can publish information to a corresponding node hosted at a notification service. The notification service can then transmit an event notification message to each of the subscribers subscribing to that node.

Automatic notification system and process


Computer-implemented methods are provided for preparing an application for execution within an application execution environment and for running an application within an application execution environment. The computer-implemented methods create supplementary information for the application. The supplementary information includes an indication of a service request which is to be performed during execution of the application to obtain information from an application service. The computer-implemented methods retrieve the supplementary information for the application, and execute the application within the application execution environment. The methods perform the service request from the application execution environment independently from the execution of the application based on the supplementary information, and receive a response to the service request from the application service at the application execution environment. The method provides the response from the application execution environment to the application in response to a request from the application to perform the service request.

The present invention relates to application execution environments. In particular, it relates to running applications within application execution environments and to the preparation of applications for execution within such application execution environments.
Application execution environments provide an environment in which applications may be executed. They typically provide a number of functions which support the execution of applications within the environment. Such functions include, for example, functions which allow control over the applications running in the environment, provide access to storage, facilitate inter-application communications within the environment or allow communications with external services outside of the environment. However, there are many other functions which may be provided by an application execution environment in order to support the execution of applications. Applications running within an application execution environment may make use of these functions provided by the application execution environment in order to carry out their tasks. At a general level, any operating system may be considered as providing an application execution environment. However, more specialized application execution environments exist which are designed to support rapid high-volume online transaction processing, such as Customer Information Control System, CICS® (CICS is a trademark of International Business Machines Corporation, registered in many jurisdictions worldwide). CICS® is commonly used within a mainframe computing system environment to manage large-scale computer processing transactions for "enterprise" user organizations such as banks, brokerage firms, insurance companies, large retailers, and so on. More specialized application execution environments, such as CICS®, typically provide functionality which goes beyond (or augments) the functionality provided by an operating system. Such application execution environments may be provided as middleware running on top of an operating system.

This patent is subject to a terminal disclaimer.

Running an application within an application execution environment and preparation of an application for the same


Nearly orthogonal latin hypercubes are used in optimization algorithms for creating an expanded and synthetically-generated data set to improve an initial optimization algorithm.

Optimization algorithms have been utilized to be able to optimize processes in which a large amount of data is processed from sensors which sense various of the measurable quantities within a monitored system. This large amount of data has been utilized in the past to derive an initial optimization algorithm which is then used to optimize a monitored system.
Optimization algorithms are those that can include both diagnostics and prognostications. One such system involving the PRDICTR algorithm is described in U.S. patent application Ser. No. 12/548,683 by Carolyn Spier filed on Aug. 27, 2009, assigned to the assignee hereof and incorporated herein by reference.
When however it is important to embed an optimization algorithm at a point of performance such as on a vehicle, due to the large amount of data originally required for providing robust optimization, there needs to be a way of reducing the amount of sensor data required in order to derive an initial optimization algorithm, so that the optimization algorithm can be placed at the point of performance.
Thus, there is a need to create an optimization algorithm that one can embed at the point of performance. The normal method of creating such an algorithm is precluded because of the necessity of collecting a large amount of data and then finding a vector through the data that has the highest coefficient of goodness of fit. For vehicle embedded systems, this approach is impractical. Moreover, vehicle health monitoring systems invariably have small numbers of monitored parameters in which only a few variables on vehicles are monitored.
Note that vehicles exhibit a number of different failure modes and monitored conditions can include the number of hours of operation, a number of interactions, and numbers of specific environments that are encountered by the vehicle. However, if the monitored data is a small data set, then oftentimes it is difficult to justify a complete optimization algorithm study such as that produced by the aforementioned PRDICTR algorithm.
Note that if one could wait to collect data on all of the failure modes of a vehicle and then find the performance vector that suggests how the system is going to fail in a new environment, then it would be possible to derive the appropriate optimization algorithm.
However, when the amount of data is limited and one cannot interpolate a vector through the modest amount of data, there needs to be a way of synthetically generating data in order to be able to derive an initial optimization algorithm.

Nearly orthogonal latin hypercubes for optimization algorithms

BAE Systems Information and Electronic Systems Integration Inc.


A panel including a substrate coated with a thermochromic layer, and a plurality of electric conductive layers formed of an electric conductive material. Here, the infrared ray transmittance of the panel is randomly or desirably adjusted as an electric conductive layer generates heat, and the color tone of the panel may be adjusted as desired by a user.

1. Field
One or more embodiments of the present invention relate to a panel including a thermochromic layer, and to a panel including a thermochromic layer and an electric conductive layer.
2. Description of Related Art
With the rapid increase of the cost of chemical energy sources such as petroleum, demand for development of a new energy source is increasing. However, it is also important to control energy consumption. In a typical household, 60% or more of energy is consumed in heating and cooling. In particular, about 24% of the consumed energy escapes through windows of typical houses and buildings.
Various efforts have been made to reduce the amount of energy lost through windows. For example, the size of windows may be controlled, or a high insulation window may be installed.
An example of a high insulation window is a panel including a glass coated with a thermochromic layer for adjusting energy inflow by adjustment of infrared ray transmittance.

Panel including thermochromic layer and electric conductive layer


A method for restoring a wireless backhaul link includes: measuring the signal quality of a first wireless backhaul link between a first new radio (NR) host station being accessed by a NR wireless backhaul base station and the NR wireless backhaul base station; in a case that the signal quality of the first wireless backhaul link is less than a link reselection threshold corresponding to the NR wireless backhaul base station, beginning a new search for an adjacent NR host station; measuring signal quality of a second wireless backhaul link between the NR wireless backhaul base station and a second NR donor base station; and initiating, when the signal quality of the second wireless backhaul link being greater than a first threshold continues a duration exceeding a first time length, a random access request to the second NR donor base station, so as to establish a wireless backhaul link with the second NR donor base station.

With the development of communication technology, mobile communication has experienced a leap development from voice services to mobile broadband data services, which not only profoundly changes people's lifestyles, but also greatly promoted social and economic development. As two main driving forces for the development of future mobile communication, the mobile Internet and the Internet of Things provide broad application scenarios for the 5th Generation (5G) mobile communications technology. Facing 2020 and the future, the thousand times growth of data traffic, hundreds of billions of devices connected and diversified service requirement will all pose severe challenges to the design of 5G systems. 5G will meet people's requirement for ultra-high traffic density, ultra-high density of connection number, and ultra-high mobility, and can provide users with the ultimate service experience of high-definition video, virtual reality, augmented reality, cloud desktops, and online games. 5G will infiltrate the Internet of Things and other fields, and be deeply integrated into industrial facilities, medical equipment, transportation facilities, etc., thereby fully achieving the "Internet of Everything", and effectively satisfying the information service requirement of vertical industries such as industry, medical treatment, transportation, and etc.
In order to meet the requirements of future 5G services that are more diverse, higher speed, and more connection number, it is required to improve spectrum efficiency greatly of 5G networks. And high-frequency communication technology can be an important candidate technology to satisfy the requirement of improving spectrum efficiency and ultra-high speed for 5G networks. The 3rd Generation Partnership Project (3GPP) has also launched a lot of standardization work for high-frequency communications.
Due to the transmission characteristics of high frequency bands, small cells are typically used for high frequency communication. However, in a case that each small cell is provided with traditional backhaul, such as optical fiber, it will require a lot of overhead such as a great quantity of fiber (especially in the case of dense deployment of 5G networks), and appropriate sites are required to support the placement of backhaul. In the New Radio (NR), high frequency bands will be mainly used and be preferably used as wireless backhaul frequency bands. However, high frequency bands are also characterized with easily being blocked and leading to a link break off. Therefore, how to prevent the wireless backhaul link from breaking off is a technical problem to be solved urgently.

Methods of restoring wireless backhaul link and establishing wireless backhaul link, NR wireless backhaul base station, and NR donor base station

BEIJING XIAOMI MOBILE SOFTWARE CO., LTD.


The ultrasonic instrument includes a shaft having an integral sheath of PTFE encompassing the shaft and attached solely to the shaft. At the proximal end of the shaft, wrench flats are exposed through openings in the sheath and grooves cooperate with complementary ribs on the sheath, to prevent relative longitudinal and rotational displacement of the sheath and shaft. The sheath is in contact with the shaft at the nodes along the shaft. The diameter of the sheath is about 5 mm whereby the instrument may be used with a 5 mm trocar port. To manufacture the instrument, the sheath is initially formed to a diameter equal to or less than the diameter of the shaft and then mechanically expanded. Subsequently, the sheath is heat-shrunk about the shaft and rolled continuously along the shaft, except at regions corresponding to the nodes along the shaft, to expand the sheath to a larger diameter to space the sheath from the shaft except at the nodes of the shaft.

Use of ultrasonically vibrating surgical blades to cut and coagulate tissue has previously been disclosed, for example, in U.S. Pat. No. 2,714,890. The benefits of using ultrasonic energy for tissue dissection and coagulation are many, e.g., enhanced cutting speed, simultaneous hemostasis and cutting, freedom from electrical hazards since no electrical current flows in the tissue, elimination of smoke and reduced build-up of eschar and other material on the blade. An ultrasonic surgical instrument adapted for laparoscopic usage under endoscopic observation has been described in prior U.S. patent application Ser. Nos. 07/670,186, filed Mar. 15, 1991, now abandoned and 07/828,697, filed Feb. 3, 1992, now abandoned, disclosures of which are incorporated herein by reference. From a review of those disclosures, it will be appreciated that there is an evolving use of ultrasonic instruments for laparoscopic surgery. In those instruments, a shaft diameter of approximately 10 mm or more was believed necessary for a number of reasons: (1) the ultrasonic energy transmission waveguide, i.e., a shaft, should have a sufficiently large diameter to provide the necessary strength to carry the desired ultrasonic energy without failure from fatigue; (2) there should be sufficient space for a protective sheath which surrounds the waveguide, i.e., the shaft, to prevent coupling of the ultrasonic energy to tissue or devices adjacent to it; and (3) the shaft should have a sufficiently large diameter to obtain the desired stiffness to allow the surgeon to supply side, as well as longitudinal, forces to the tissue.
While the ultrasonic laparoscopic instruments disclosed in the above-identified prior applications, of common assignee herewith, are eminently suitable for their intended purposes, there is the limitation that they require use of a 10 mm diameter trocar port which, in turn, creates a larger incision and scar than would be the case when using smaller available ports. Because most laparoscopic procedures involve the use of both 5 and 10 mm trocar ports, a 5 mm diameter device for laparoscopic surgery would enable the surgeon to choose from a greater variety of approaches to the surgical site because a 5 mm device can be used through either a 5 or 10 mm trocar port. There are, however, difficulties in reducing the diameter of an ultrasonic laparoscopic instrument for use with a 5 mm trocar port consistent with the above-identified criteria for effectively transmitting ultrasonic energy to the blade to enable dissection and coagulation. For example, in most prior ultrasonic devices which employ a sheath, it is required that the sheath be telescoped over the shaft from one end. Consequently, the sheath must have a larger diameter than the outside diameter of the shaft and at least one of the blade and shaft coupling at its proximal end to the handpiece. Where the sheath inner diameter is smaller than the outside diameter of both the blade and the shaft coupling to the ultrasonic transducer, the acoustic drive train, i.e., the shaft, must be formed into separable pieces to enable the user to remove the sheath. In this connection, see U.S. Pat. No. 3,861,391.

Laparoscopic ultrasonic surgical instrument and methods for manufacturing the instruments


A semiconductor light emitting device has at least a substrate, an n-type GaN type semiconductor layer, an active layer, and a p-type GaN type semiconductor layer which are laminated on each other. In a first annealing process, the semiconductor light emitting device is annealing-processed thereby activating the p-type GaN type semiconductor layer. A metal mask is formed to cover an electric current introducing area of a surface of the p-type GaN type semiconductor layer. In a second annealing process the semiconductor light emitting device is annealing-processed thereby inactivating the p-type GaN type semiconductor layer.

The present invention relates to a method for manufacturing a light emitting device.
Recently, the semiconductor light emitting device using gallium nitride and related compound semiconductors (hereinafter called III-V nitride semiconductors) has attracted a lot of attention. Accordingly, the device structure suitable for the III-V nitride semiconductor has been studied.
Here, III-V nitride semiconductor is defined as the semiconductor of the compound of GaN of III group atom with N of V group atom, the compound of Ga of III group atom with another III group atom such as Al, In and others which is substituted for a part of Ga, and the compound of N of V group atom with another V group atom such as P, As and others which is substituted for a part of N.
Heretofore, various types of element structure have been proposed in order to improve the characteristics of the semiconductor light emitting device. As a method for improving a basic characteristic such as the threshold of oscillation, there is a method for providing structure to restrict the path for electric current.
As one of the methods to restrict the electric current path, there is a method of removing an area around the path in a p-type layer of the surface of the semiconductor by wet etching or dry etching.
However, the method has following problems.
The method of wet etching can not be used, because an etching solution suitable for the semiconductor of the GaN related compound has not been discovered.
In the method by the dry etching, an active layer may be damaged by the etching of the p-type layer, thereby reducing the light emitting characteristic.
Therefore, at the present time, a method by annealing process is devised as shown in FIGS. 3a and 3b.
A semiconductor light emitting device of FIG. 3a has a layer structure comprising a III-V nitride semiconductor on a substrate 21, which comprises an n-type buffer layer 22, n-type GaN clad layer 23, n-type AlGaN clad layer 24, InGaN active layer 25, p-type clad layer 26, and p-type GaN contact layer 27.
In the method, the entire semiconductor layer is annealing-processed, thereby activating the p-type layers. Thereafter, a mask 28 of insulation material is mounted on the surface of the p-type contact layer 27, and the semiconductor is annealing-processed in an ambient of hydrogen. As a result, p-type layers 29 not covered by the mask 28 are made high resistance to form a narrow electric current path as shown in FIG. 3a.
Next, the mask 28 is removed and a p-electrode 30 of Au is mounted on a current injection area of the p-type contact layer 27 as shown in FIG. 3b.
On the other hand, the n-type clad layer 23 is exposed by etching a part of the semiconductor layer (FIG. 3a), and an n-electrode 31 of Au is mounted on the surface of the n-type clad layer 23, thereby forming a semiconductor light emitting device (FIG. 3b).
However, in the method, the mask 28 of insulation material must be removed, and the removed portion is exposed in the atmosphere. The exposed portion is oxidized to form an oxidation film on the portion. Furthermore, in order to reduce the contact resistance of the electrode 31, the semiconductor layer is annealing-processed again. As a result, hydrogen diffuses from the high resistance portion to the low resistance portion of the narrow path, thereby increasing the resistance of the narrow path.

Method for manufacturing a semiconductor light emitting device


An aerospace fastener comprises a blot with a roll-formed thread, and a nut with a similar thread having a uniform pitch P. The bolt has a cylindrical shank, a threaded tip and a run-out zone between the shank and tip. The thread root in the run-out follows a smooth S-shaped curve with the concave portion preferably having a radius in the range of from 2P to 2.7P. The run-out extends from 1.4P to 2.3P from the maximum grip plane of the bolt, and preferably extends from 1.6P to 2P from the maximum grip plane. The root of the thread in the run-out lies within an envelope defined by boundaries which take into account the maximum and minimum material conditions of the bolt. The nut has a run-in truncating the crest of the nut thread complementary to the run-out to clear the root of the bolt thread when the nut is assembled on the bolt in the minimum grip condition. This permits the nut to be assembled on the bolt further than in a conventional combination, and shortening of the nut and bolt by at least 1P to save weight.

This invention concerns lightweight fasteners such as for aerospace applications. A bolt with a roll formed thread and better than usual effective thread run-out is provided. The bolt may be used with a shortened nut with a truncated thread for clearance from the bolt thread run-out. Because of such improvements the nut and bolt can each be up to one pitch length shorter than a conventional nut and bolt. Alternatively, the bolt may be used with a conventional length nut or collar, and the tensile strength of the fastener increased.
Further, such a bolt may be used with a swaged collar rather than a nut, and the enhanced strength or shortened length can be advantageous. The bolt may have some of the thread on its tip deleted to form longitudinal flutes which lock a swaged collar or nut onto the bolt. In such an embodiment, the decreased strength due to deleting some of the thread may be offset by increased strength provided by the improved bolt.
Weight of the fasteners is of great concern in airplanes and other aerospace applications. The nuts, bolts, rivets and the like employed for securing the structural elements of an airplane contribute a substantial portion to the total weight of the airplane since very large numbers of such fasteners are used. It is not unusual to use over 100,000 fasteners on one airplane. Thus, there has been a long effort to reduce the weight of fasteners without decreasing the strength, or preferably decreasing weight while increasing strength. Even an apparently small decrease in weight on an individual fastener can have a large impact on the total weight of an airplane.
Nuts and bolts are ubiquitous fasteners on aircraft. The vast majority of aircraft bolts have roll formed threads because of the superior fatigue properties of these threads as compared with machined or ground threads. To make such bolts, a machined metal blank is rolled between a pair of thread forming dies for placing a thread on the blank. Metal is not removed from the blank in this process, but instead the metal is deformed as the thread forming dies press in to form the root and flanks of the thread. The displaced metal flows outwardly to form the crest of the thread.
A conventional thread rolling die has uniform thread forming ridges and grooves over most of its width for making a uniform thread. The edges of the dies are, however, chamfered or rounded somewhat to avoid damage to the die. This chamfer results in a short run-out zone between the cylindrical shank of the bolt and the end or tip on which the thread is fully formed. The run-out zone is also advantageous on the bolt since it avoids a sudden change in cross section of the bolt which could weaken the bolt, particularly in fatigue.
In conventional threaded aircraft fasteners the run-out zone has a length of up to two times the pitch of the thread. Within the run-out zone the root of the thread is not fully developed because of the chamfer on the roll forming die. That is, the thread is shallower than in the portion of the bolt where the thread is fully developed. Concomitantly, the crest of the thread in the run-out may not be fully developed since less metal is displaced from the root. Thus, in the run-out the outside diameter of the crest of the thread is less than the major diameter in the fully threaded portion. The flanks of the bolt thread, which carry the tensile load on the nut and bolt combination, may or may not be fully developed in the run-out. Thus, in the run-out the thread is referred to as imperfect and is nonfunctional.
The maximum length of the run-out under the specifications used in the aerospace industry is 2P, where P is the pitch of the thread. The actual length of the run-out due to normal manufacturing variations is in the range of from 1.5P to 2P.
Nuts used with conventional aerospace fasteners typically have a counterbore collar concentric with the threaded hole through the nut. The length of the counterbore is such that when fully tightened, the threaded portion of the nut does not extend into the run-out on the bolt. If it were to extend into the run-out there would be thread interference between the crest of the nut thread and the incompletely formed root of the bolt thread, and the nut could not be properly tightened on the parts being secured.
The length of the cylindrical shank of a bolt from its head to the beginning of the thread run-out is referred to as the "maximum grip." If the fastener has a flush head, the grip is from the top of the head to the end of the shank. With a raised head not countersunk into one of the parts being secured, the grip is the cylindrical, unthreaded length of the shank.
The plane corresponding to the maximum thickness of parts to be held by a bolt is sometimes also referred to as the "maximum grip," or "maximum grip plane".
Terminology referring to the form and size of threads as used throughout this specification are those commonly applied t screw threads such as set forth at pages 45-1 through 45-8 of Tool Engineers Handbook, 2nd Ed., American Society of Tool Engineers, 1959. High strength aerospace fasteners are designed so that the maximum grip corresponds to the maximum thickness of the parts being secured together. The minimum grip is typically one-sixteenth inch (1.6 mm) less than the maximum grip. For example, an aircraft fastener may have a nominal length of one quarter inch (6.35 mm) for the maximum grip. The fastener would be used for securing together parts having a total thickness in the range of from three-sixteenths inch (4.76 mm) to onequarter inch (6.35 mm). If the thickness of parts being secured together is exactly one-quarter inch, for example, the installer has the option of selecting either of two conventional fasteners, one to fit at its minimum grip length or the other at its maximum grip length.
The depth of the nut counterbore in a conventional aerospace fastener is the difference between the maximum grip and minimum grip plus about 1.5P. A small amount may be added to account for accumulated manufacturing tolerances. This means when the nut is secured against parts having the minimum grip, the end of the thread in the nut is at the end of the run-out, a distance of about 1.5P from the end of the cylindrical shank of the bolt. When the nut is secured against parts having the maximum grip, the thread in the nut stops about one-sixteenth inch (1.6 mm) plus 1.5P from the end of the run-out. The same concept is present in metric bolts, and the difference between minimum grip and maximum grip is typically one millimeter or two millimeters. Thus, the depth of a nut counterbore is 1 mm or 2 mm plus 1.5P.
It has been recognized that if the thread run-out were reduced to 1P or less instead of 2P, the length of the counterbore on the nut could be reduced, thereby reducing the total length of the nut. This also permits a shortening of the bolt thread and overall length by 1P.
The weight savings in an airplane by reducing the length of both the nut and bolt by as little as 1P can be quite substantial.
Aerospace bolts have been developed with an effective run-out of only about 1P. In one such design, for example, a special roll forming die is used. Instead of tapering the root of the thread and producing an imperfect thread, a full thread is carried to within 1P of the cylindrical shank. The root of the thread then increases in a very short distance toward the shank diameter. This has permitted reduction of the total length of the nut and bolt by 1P without significantly reducing the tensile strength of the nut and bolt combination.
This type of short run-out bolt has drastically reduced fatigue properties as compared with a conventional bolt having a run-out length of up to 2P. An exemplary tensile fatigue test simulates an application where the parts secured together do not have parallel faces. For example, two parts may be secured together with the face engaged by the nut being out of perpendicular with the axis of the bolt shank by three degrees.
In a three degree tensile fatigue test there is comparable off-axis loading which induces some bending in the bolt. In an exemplary fatigue test an assembly of a nut and bolt is cycled between an upper tensile load of 50% of the rated capacity of the combination and a minimum load of 5% of the rated load bearing capacity of the combination. The number of cycles to failure is measured.
In such a test the bolt with a modified thread having only an effective 1P run-out has only about 20% of the fatigue life of a conventional bolt with up to 2P run-out. For example, if a conventional bolt has fatigue life of 100,000 cycles, the modified lightweight bolt may have a fatigue life as low as 20,000 cycles in the three degree off-axis fatigue test. The adverse impact on tensile fatigue is apparently due to having a rather deep thread root close to the maximum grip plane at the end of the cylindrical shank. Such a short run-out bolt is also substantially poorer in a lap shear test than a bolt with a run-out of 2P.
Thus, there are two types of shortcomings in existing aerospace fasteners. In one type of fastener there is adequate tensile strength and tensile fatigue strength, but the fastener is relatively long and therefore relatively heavy. On the other hand, a fastener has been produced which is shorter and hence lighter, but the tensile fatigue properties of that fastener are significantly adversely affected.
Thus, it is desirable to provide an aerospace fastener with a roll formed thread where the length of the nut and bolt can be reduced without reducing either the tension capability of the combination or the off-axis tensile fatigue strength of the combination. It is desirable to provide the option of reducing length, and hence, weight, or maintaining a standard length and increasing strength of the fastener. It is particularly desirable to provide such a combination of a nut and bolt that has increased strength as compared with conventional aerospace fasteners. It is also desirable to make such a fastener using roll forming dies relatively unchanged from conventional roll forming dies.
When designing aerospace fasteners for high volume production one must take into account manufacturing tolerances. The tolerances are quite small but the parts themselves are small and these tolerances should be accounted for in the thread run-out.
The thread on a fastener has a specified pitch diameter D.sub.P. The blank on which the thread is rolled is typically machined to have a tip diameter substantially the same as the pitch diameter of the finished thread. There is a certain tolerance, however, on the machined diameter and the actual size may be slightly larger or slightly smaller than the nominal. In the parlance of the art when the blank is oversize at the tolerance limit, it is referred to as the maximum material condition, and when it is undersize at the tolerance limit it is referred to as the minimum material condition.
When fasteners are roll formed the actual thread dimensions differ depending on the variation of the blank diameter from the nominal diameter. Thus, the major diameter of the thread for the maximum material condition is larger than the major diameter for the minimum material condition. These may be referred to as the maximum material major diameter D.sub.MM and the minimum material major diameter D.sub.mM. Concomitantly, the minor diameter of the thread at its root also has a maximum material minor diameter D.sub.Mm and a minimum minor diameter D.sub.mm.
The nuts used with such bolts also have maximum and minimum material conditions. The maximum material condition for the nut is essentially one with the smallest hole which is within tolerance. Fasteners are designed so that when both the nut and bolt are in the maximum material condition, there is virtually no clearance between the mating threads. When either or both of the nut and bolt are at less than the maximum material condition, there is some clearance, and the maximum clearance occurs when both a nut and bolt are in the minimum material condition.
There is also a length tolerance on the shank. Thus, the location of the maximum grip plane has a small tolerance. In typical aerospace fasteners, the tolerance on the grip is -0.000 and +0.010 (0.25 mm). The bolt designer must be cognizant of this tolerance as well.
As an example, the bolt must be made so that when it has the maximum material condition and the nut with which it is used has the maximum material condition and the fastener is used on minimum grip parts, the nut can be tightened against the parts without interference by the nut thread against the root of the thread in the bolt runout. Concomitantly, the thread root and the bolt run-out should not be so small as to significantly decrease the strength properties of the bolt.
In a very high proportion of the holes where aerospace fasteners are used, the shank has an interference fit in the hole. The maximum material major diameter of the thread is smaller than the shank diameter so that the tip of the bolt can be readily inserted in the hole. It is common to provide a lead-in at the end of the shank for a smooth transition between the shank diameter and the major diameter of the thread to assist in guiding the shank into the hole. Typically, the lead-in takes the form, in a longitudinal cross section of the bolt, of a convex arc which is tangent to the shank diameter a short distance from the maximum grip plane and decreases toward the major diameter on the other side of the grip plane. Thus, at the grip plane, the bolt diameter is slightly smaller than the shank diameter. The lead-in continues to a diameter that is at least smaller than the maximum material major diameter. The lead-in is formed on the machined blank rather than being developed during the roll forming step.
A smooth continuous curve has been defined for the run-out of the thread root for maximizing strength and minimizing weight of fasteners. There are acceptable deviations from the defined curve which are within tolerance. As long as the thread root run-out falls within a carefully defined envelope, the strength of the fastener is maintained and there is no interference between the crest of the nut thread and the root of the bolt thread in the run-out.


There is provided a vehicular lamp that can be miniaturized by reducing signal lines connected to a vehicle main body. The vehicular lamp that is used for a vehicle includes a light source unit, and a signal line that connects the light source unit and a light source controlling unit for controlling lighting of the light source unit, in which the light source unit includes: a semiconductor light-emitting element; an optical member that irradiates light emitted from the semiconductor light-emitting element to the outside of the vehicle; a lighting controlling unit to which electric power is supplied from a vehicle main body and that control an electric current supplied to the semiconductor light-emitting element according to a voltage applied to the signal line by the light source controlling unit in order to control a light amount of the semiconductor light-emitting element; a current detecting resistor that is connected to the semiconductor light-emitting element in series; a current driving resistor that is connected to the signal line in series; and a comparator that sinks the current flowing into the current driving resistor and the same signal line as the signal line when a voltage is generated on the current detecting resistor by the current flowing into the semiconductor light-emitting element.

1. Field of the Invention
The present invention relates to a signal transmission system and a vehicular lamp.
2. Description of Related Art
In late years, a vehicular lamp that uses a semiconductor light-emitting element such as an LED (Light Emitting Diode) for a light source is known as disclosed, for example, in Japanese Patent Laid-Open No. 2002-231013 (see pages 2 to 6 and FIGS. 1 to 13). For safety reasons, when a light source of a vehicular lamp breaks, the vehicle informs a driver of that effect and prompts the driver for replacement of the light source. In addition, when the speed of a vehicle is fast, the vehicle increases a light amount of the light source more than it drives slowly. In this way, the front of the vehicle becomes brighter and safety of vehicle traveling is increased, in some cases.
In order to detect disconnection of a light source by a vehicle main body, a signal line, which transmits a signal to indicate disconnection of the light source from a vehicular lamp to the vehicle main body, is required. In addition, when a light amount of the light source is controlled, a signal line, which transmits a control signal from the vehicle main body to the vehicular lamp, is required. Therefore, since the number of cables connected to the vehicular lamp increases, there has been a problem that the vehicular lamp is not miniaturized in some cases. In addition, due to an increase of the number of cables, there has been a problem that it takes a long time to mount the vehicular lamp to the vehicle in some cases.

Signal transmisson system and vehicular lamp


Disclosed are compositions and methods for analyzing a target sequence in a sample. Generally, the method includes use of at least one pair of probes (Probe A and Probe B). In one embodiment, Probe A hybridizes to wanted and unwanted nucleic acid in the sample and bears a fluorophore and Probe B hybridizes to unwanted nucleic acid in the sample and bears a quencher. Fluorescence signal from Probe A hybridizing to unwanted nucleic acid is quenched by any relatively close hybridization of Probe B hereby increasing the specificity for the presence, amount or absence of the wanted target sequence. In preferred embodiments, the method is referred to as Fluorescence In-Situ Hybridization (FISH). The invention has many useful applications including rapidly detecting a microbial target sequence in a clinical sample.

1. Field of the Invention
This invention is related to the field of probe based nucleic acid sequence detection, quantitation and analysis. More specifically, this invention relates to methods and kits, which prevent the generation of false positive results in probe based assays, particularly where said probes are fluorescently labeled PNA or LNA probes.
The invention is more specifically directed to methods and kits suitable for improving the specificity and/or reliability of diagnostic tests using probes. The methods and kits of this invention are particularly well-suited for fluorescence in situ hybridization.
2. Description of the Related Art
Nucleic acid hybridization is a fundamental physiochemical process, central to the understanding of molecular biology. Probe-based assays use hybridization for the detection, quantitation and analysis of nucleic acids. Nucleic acid probes have long been used to analyze samples from a variety of sources for the presence of nucleic acids, as well as to examine clinical conditions of interest in single cells and tissues. More recently, high affinity nucleic acid probe analogs and mimics have become the preferred reagents for hybridization assays.
Locked Nucleic Acid (LNA) and Peptide Nucleic Acid (PNA) are novel high affinity probes which provide higher sensitivity and specificity than conventional DNA probes. DNA is a biological material that plays a central role in the life of living species as the agent of genetic transmission and expression, whereas LNA and PNA are recently developed totally artificial molecules, conceived in the minds of chemists and made using synthetic organic chemistry. Although LNA and PNA can employ common nucleobases (A, C, G, T, and U) and can hybridize to nucleic acids with sequence specificity according to Watson-Crick base paring rules, they differ both structurally and functionally from DNA. Peptide Nucleic Acid, despite its name, is neither a peptide nor a nucleic acid, nor is it even an acid, but a non-naturally occurring polyamide backbone composed of (aminoethyl)-glycine subunits where the nucleobases are connected to the backbone by an additional methylene carbonyl moiety. (See: U.S. Pat. No. 5,539,082 and Egholm et al., Nature 365:566-568 (1993)). Due mostly to the fact that PNA carries a net neutral electrical charge, PNA can form hybrids extremely rapidly and stably with naturally occurring nucleic acids. LNA is a nucleic acid analog created by chemically joining the 2′ oxygen and 4′ carbon of a ribonucleoside through a methylene linkage. The highly rigid structure of the resultant locked 3′-endo conformation reduces the conformational flexibility of the ribose. The increased rigidity and local organization of the LNA phosphate backbone lowers the entropic penalty for hybridization of LNA probes as compared to DNAs of the same relative composition. These structural features provide PNA and LNA probes with higher affinity for target sequences and furthermore allow PNA and LNA probes to hybridize under conditions that are destabilizing to naturally occurring nucleic acids, such as low salt concentration or in the presence of guanidinium hydrochloride. These attributes enable PNA probes to access targets, such as highly structured rRNA and double stranded DNA, known to be inaccessible to DNA probes (See: Stefano & Hyidig-Nielsen, IBC Library Series Publication #948. International Business Communication, Southborough, Mass., pp. 19-37 (1997), (Fuchs, Appl Envir Micro 64 (12) 4973-82, 1998; Efficient poly(A)+ RNA selection using LNA oligo(T) capture. Technical note, Exiqon A/S, Denmark. LNA and PNA are useful candidates for investigation when developing novel probe-based hybridization assays because of their excellent hybridization features.
Probe based assays are useful in the detection, identification and quantitation of nucleic acids. Nucleic acid probes have long been used to analyze samples for the presence of nucleic acid from a bacteria, fungi, virus or other organism (See for example; U.S. Pat. Nos. 4,851,330, 5,288,611, 5,567,587, 5,601,984 and 5,612,183). Probe-based assays are also useful for examining genetically based clinical conditions of interest. Despite the high specificity of LNA and PNA probes as compared to naturally occurring nucleic acid probes, it is common to encounter sequence regions where it is very difficult to design a probe which allows exclusive detection of the desired target in a particular assay format.
The use of PNA probe mixtures have previously been described as a way to target two adjacent target sequences (US2002058278) as a means to increase specificity, however, that concept required each of the two PNA probes hybridizing the adjacent target sequences to be extended with an arm segment capable of forming a triplex with a third labeled PNA probe, such that a total of three probes were required. In addition, the use of a fourth probe or antibody was proposed.
Blocker probes are nucleic acid or non-nucleic acid probes that can be used to suppress the binding of the probing nucleobase sequence of the probe to an unwanted target sequence. Preferred blocker probes are PNA probes (See: Coull et al., U.S. Pat. No. 6,110,676). Typically blocker probes are closely related to the probing nucleobase sequence and preferably they comprise one or more single point mutations as compared with the probe sought to be detected in the assay. Blocker probes operate by hybridizing to non-target sequences, thereby preventing these sequences from being available for hybridization with the detectable probe. The competition set up between the blocker probe and the detectable probe ensures that each probe will only bind to highly complementary targets, increasing the specificity of the assay. Generally and preferably, blocker probes are directed towards a particular single non-target sequence which differs by at least one nucleobase from the target sequence.
The "Hybridization Probes" method (U.S. Pat. No. 6,174,670) describes use of two DNA probes which hybridize to adjacent target sequences, where one DNA probe is labeled with a fluorophore (donor) and the other DNA probe is labeled with another fluorophore (acceptor), such that simultaneous hybridization of the two probes facilitate Fluorescence Resonance Energy Transfer (FRET). The method teaches that FRET occurs as the energy from the excitation of the donor fluorophore is transferred to the donor fluorophore where it is emitted at the emission wavelength of the donor fluorophore. The combined specificity of the two probes is greater than that of either probe alone, as the detectable signal is dependent on the specific hybridization of two DNA probes. Use of Hybridization Probes is limited to selected donor-acceptor fluorophore pairs and instrumentation, such as the LIGHTCYCLER™, with a special combination of excitation filter for the donor fluorophore and emission filter for the acceptor fluorophore. This method is not directly applicable in, for example, fluorescence in situ hybridization assays using standard fluorescence microscope filter sets.
It would be desirable to have a method for improving the specificity for a target sequence that employs quenching of the fluorescence from binding of fluorophore-labeled probes to unwanted target sequences.

Method for improved specificity in probe based assays


In formation of a fine pattern with direct electron beam delineation, disclosed is a method of obtaining parameters on an electron scattering intensity distribution expressed with a double Gaussian distribution obtained when exposing a resist with an electron beam. A resist on a substrate is exposed with an electron beam in accordance with an evaluation pattern which comprises a plurality of basic checked patterns each comprising longitudinal and lateral exposed stripes. The basic checked patterns are successively arranged longitudinally and laterally at predetermined intervals on a plane so as to form a plurality of longitudinal pattern rows and lateral pattern rows, widths of the stripes of the basic checked patterns in each of the lateral pattern rows being successively changed so as to be different from each other. The exposure doses for the basic checked patterns in each of the longitudinal pattern rows are successively changed so as to be different at every basic checked pattern, thereby obtaining, as a critical exposure dose, the minimum exposure dose in each of the longitudinal pattern rows on the basis of removed or remaining states of the non-exposed portions of the basic checked patterns to obtain the respective parameters.

The present invention relates generally to formation of a fine pattern with direct electron beam delineation, and more particularly to an exposure evaluating method of obtaining an electron beam scattering intensity distribution for a proximity effect correction in the fine-pattern formation.
In performing a so-called electron beam exposure, an electron beam scattering occurs in a resist, by which scattering the exposure area becomes wider than the electron beam illumination area so as to enhance affection of the scattering to make it difficult to obtain a pattern with a desirable dimension. This is referred to as proximity effects. Thus, formation of a fine pattern requires the proximity effect correction.
Generally, the electron beam scattering intensity distribution can be expressed by the following double Gaussian distribution under the condition that in a coordinate system the center point is taken as xl and the scattering intensity is E(r). ##EQU1## where .alpha. represents the spread of the forward scattering occuring in the resist, .beta. designates the spread of the back scattering generated by reflection from the substrate, and depicts the reflection coefficient of the back scattering.
When a pattern represented by a region S1 is exposed with an exposure dose (quantity of illumination) Q.sub.E, the absorbed dose Q(r) in the coordinate R can be expressed in accordance with the following equation. EQU Q(r)=.sqroot..sub.s1.spsb.Q.sub.E .multidot.E(r-x1)d.sup.2 x1 . . . . . . . . . . . . (2)
Secondly, when this pattern is exposed with an exposure dose Q.sub.E1 and the resist in the coordinate r is first removed after development, the dissolved absorbed dose Qc of the resist can be diven in accordance with the following equation. EQU Qc=.sqroot..sub.s1.spsb.Q.sub.E1 .multidot.E(r-x1)d.sup.2 x1 . . . . . . . . . . . . (3)
When carrying out the proximity effect correction, for forming an expected pattern, after obtaining the exposure region S1 and the exposure dose Q.sub.E1 to satisfy the condition that the absorbed dose Q(r) in the equation (2) is greater than the dissolved absorbed dose Qc in the region including the expected pattern but smaller than the dissolved absorbed dose Qc, the exposure region S1 is exposed with the exposure dose Q.sub.E1 so as to result in execution of the proximity effect correction. Although the above description has been made in terms of using a positive resist, with respect to a negative resist, the proximity effect correction can be effected by a similar manner in which the resist-removing portions is considered as resist-remaining portions.
Generally, the proximity effect correction is made by setting a number of evaluation points on the border line of the expected pattern and setting up an equation so as to satisfy the equation (3) on all of the evaluation points, thereby obtaining the exposure region and the exposure dose which satisfy the above-mentioned condition as the solution of the set-up equation. At this time, in the equation (3), the forward scattering spread .alpha., the back scattering spread .beta., the reflection coefficient .eta. and the resist dissolved absorbed dose Qc becomes parameters depending upon a process. Here, these parameters depend upon the material of the resist, development condition of the resist, material of the substrate, acceleration voltage of the electron beam and others and are hence required to be renewed if at least one of them changes. Further, of the aforementioned parameters, the resist dissolved absorbed dose Qc can be easily obtained because it can be defined as the exposure dose at the time that the film thickness of the resist first becomes zero when exposing a pattern extremely wider than the scattering length of the electron beam. Accordingly, it is required to easily obtain .alpha., .beta., and .eta. of the aforementioned parameters. In addition, in the equation (3), .alpha. is generally known to be about 0.1 to 0.3 .mu.m and the correction effect can be obtained even if approximating as .alpha.=0, and therefore there is no problem in terms of obtaining only .beta. and .eta..
A description will be made hereinbelow with respect to known methods of obtaining the parameters .alpha., .beta., and .eta..

Electron beam exposure evaluation method

Matsushita Electric Industrial Co., Ltd.