A tool for controlling azimuth and/or inclination in a wellbore and methods for utilizing the same is disclosed. The tool generally comprises a freely rotating mandrel, for transmitting drilling forces, contained within two eccentric sleeves. The outer sleeve has an eccentric longitudinal bore that forms a pregnant or weighted side that seeks the low-side of the wellbore. Two gauge inserts or stabilizer shoes are provided on either side of the outer sleeve at ninety degrees to the pregnant housing. The inner sleeve has a further eccentric longitudinal bore that contains the freely rotating mandrel. The mandrel is attached to the drill string at one end and to the drilling bit at the other. The position of the inner sleeve may be controlled, at will from the surface, so that the eccentric is kept to one side of the outer housing, thus transmitting a fulcrum force to the bit and controlling the azimuth and/or inclination of the wellbore. The pregnant housing contains drive means and assorted logic for controlling the position with respect to the pregnant housing of the eccentric bore of the inner sleeve.

The formation through which a wellbore is drilled exerts a variable force on the drill string at all times. This variable force is essentially due to the clockwise rotary motion of the bit, the weight applied to the drill bit and the strata of the formation. Formation is a general term used to define the material--namely rock, sand, shale, clay, etc.--that the wellbore will pass through in order to open a pathway or conduit to a producing formation. This variable force will result in a variable change in the direction of the wellbore.
The formation is generally layered by the action of nature over millions of years and is not necessarily level. The formation will have dips, defined as a change in direction of the layers of the formation, which can extend either upward or downward. As the drill bit moves into a dip or from one type of formation to another, the force on the drill bit will change and cause the drill bit to wander up, down, right or left. This wandering is the natural result of the reaction of the formation to the clockwise torque and forward drilling force exerted by the drill bit on the formation. Mathematically the result can be viewed as a simple vector cross product between the torque force and the drilling force or weight on bit. The cross product results in a component force towards the right of the drilling force. The industrial term given to this effect is "bit-walk" and many methods to control or re-direct "bit-walk" have been tried in the industry.
Bit-walk is predictable, but the magnitude and, frequently, the direction of bit-walk are generally unpredictable. Looking at the vector cross product model, it can be seen that as the drilling force or weight on bit is varied, the cross product varies. Or, as the RPM of the drill string is varied, the cross product varies. Or, as the formation changes, the cross product changes. In drilling a wellbore, all of these forces constantly vary; thus, the magnitude of bit-walk constantly changes. The industry has learned to control the effects of bit-walk in a vertical hole by varying the torque and weight on bit while drilling a vertical hole. However, in an inclined (non-vertical) hole bit-walk causes a number of problems.
By industry definition, once an inclined hole is established, the side of the wellbore nearest to true vertical is called the "low-side" of the hole. The opposite side of the hole is referred to as "high-side" and is used as a reference point throughout the wellbore drilling operation. The drilling force follows the longitudinal extension of the wellbore; thus, the drilling force is parallel to and spaced from the low-side of the hole. Since bit-walk is the result of applied torque and drilling force, then it can be anticipated that normal bit-walk will be to the right of the low-side of the hole. This definition applies in all wellbores.
In a vertical hole or slightly inclined hole, bit-walk may be controlled by developing as much rigidity as possible in the lower portion of the drill string near to the drill bit. This can be and generally is accomplished by using drill string components of high rigidity and weight (drill collars or heavy-weight drill pipe) and stabilizers. A stabilizer, well known in the industry, is a tubular member with a combination of radial blades, often having a helical configuration, circumferentially arranged around the tubular and extending beyond the outer diameter of the tubular. The extension of the stabilizer blades is limited to the diameter of the drill bit. Thus, the stabilizer will work in a stable hole; however, if the wellbore washes out (increases in diameter due to formation or other downhole mechanical or hydraulic effects) or where the lateral force exerted by the blades is less than the torque effect of the drill bit, then the stabilizer loses its effectiveness and bit-walk will occur. In a highly inclined or horizontal well, bit-walk becomes a major problem.
Very often the driller wishes to deviate the wellbore or control its direction to a given point within a producing formation. This operation is known as directional drilling. For example, a water injection well in an oil field is generally positioned at the edges of the field and at a low point in that field (or formation). A vertical wellbore will be established and the wellbore "kicked-off" from vertical so that an inclined (or even horizontal) wellbore results. It is now necessary to selectively guide the drill bit and string to the required point in the relevant formation. In order to achieve this objective, control of the wellbore is required in both the vertical plane (i.e. up and down) and in the horizontal plane (i.e., left and right).
At present, in order to deviate a hole left or right, the driller can choose from a series of special downhole tools or techniques. The industry often employs downhole motors and bent subs. More recently the steerable motor has become popular, although it uses similar precepts employed by the downhole motor and bent sub. Both of these tools act in a similar manner and both require that the drill string not be rotated in order to influence and control the wellbore direction.
A bent sub, a short tubular that has a slight bend to one side, is attached to the drill string, followed by a survey instrument, of which an MWD tool (Measurement While Drilling which passes wellbore directional information to the surface) is one generic type, followed by a downhole motor attached to the drill bit. The drill string is lowered into the wellbore and rotated until the MWD tool indicates that the leading edge of the drill bit is facing in the desired direction. Weight is applied to the bit through the drill collars and, by pumping drilling fluid through the drill string, the downhole motor rotates the bit. As the bit cuts the wellbore in the required inclination and direction, the drill string is advanced. When drilling with a bent sub and motor, after the correct inclination and direction are established, the entire string is tripped to the surface, the bottom hole assembly (bent sub, downhole motor and drill bit) replaced with a single drill bit, the string is then tripped into the wellbore, and regular drilling operations restarted. This procedure will be repeated if the direction of the wellbore is unsatisfactory.
The advantage of a steerable motor is that the assembly does not require tripping immediately after the correct inclination and direction are established; the motor can be retained and will drill as a conventional "rotary assembly". Whenever the assembly is tripped, a new bottom hole assembly will be configured which will, theoretically, allow continuation of the wellbore along the correct plane and at the correct angle from vertical.
It follows that the deeper or longer the wellbore, more time will be used in making a return trip whenever tools have to be changed. For example, the bent sub may not have enough angle which will always require a round trip.
One of the earlier inventions giving sufficient control to deviate and start an inclined hole from or control bit-walk in a vertical wellbore may be in found U.S. Pat. No. 3,561,549 entitled Slant Drilling Tools for Oil Wells by Garrison and Tschirky. Garrison et al. disclose an improvement in which a non-rotating sleeve having a plurality of fins (or wedges) on one side is placed immediately below a downhole motor in turn attached to a bit. This device acts in a similar manner to an offset packer and biases the downhole assembly away from the fins (or wedges). The device must be orientated like an offset packer before commencing drilling operations. Once the wellbore is established in the desired direction, the device must be taken out of service by a round trip out of and back into the wellbore. The disclosure discusses a second orientation device above the downhole motor. This device is more properly applied when starting an initial inclination or when correcting a vertical hole which has drifted from true vertical.
U.S. Pat. No. 4,220,213 by Hamilton discloses a Method and Apparatus for Self Orientating a Drill String while Drilling a Wellbore. The device consists of an offset mandrel with a rotatable tubular extending through the mandrel and a shoe, laterally attached to the outside of the mandrel, which slides along the wellbore. The offset mandrel is heavily weighted (by supplying sufficient material when manufacturing the mandrel) at 90 degrees to the "shoe." This tool is attached to the drill string immediately above the drill bit and the remaining drill string contains the usual downhole tools for weight, flexibility, control of inclination, wellbore surveying, etc. The heavily weighted portion of the Hamilton mandrel seeks the low-side of the hole, thus orientating the shoe to one side of the wellbore. The sliding shoe places a bias on the attached drill bit in a similar manner as does an offset packer or the Garrison et al. device.
The tool is designed to take advantage of gravity because the heavy side of the mandrel will seek the low-side of the hole. The shoe is attached to the mandrel on the side and one-quarter along the circumference. The device is designed to counteract the vector cross product of torque and drilling force which normally causes the bit to walk to the right. This means that a counter force must be applied that biases the bit to the left; thus, the normal position of the shoe is on the right. In using the tool, the weighted bottom seeks the low-side of the wellbore, the shoe rubs along the right side of the wellbore and the tubular rotates freely within the mandrel supplying drilling torque to the bit. The extension of the shoe beyond the bit circumference would be set by the size of the wellbore.
This tool is known to work: however, it suffers the same drawback as does the offset packer and the tool of Garrison et al., namely if the bit-walk forces change, then the tool must be changed or removed necessitating a round trip.
U.S. Pat. No. 4,638,873 to Welbom discloses a Direction and Angle Maintenance Tool and Method for Adjusting and Maintaining the Angle of a Directionally Drilled Borehole. This tool is essentially an improvement to the Hamilton device and operates in much the same manner. Welborn uses a spring-loaded shoe and a weighted heavy side which can accommodate a gauge insert held in place by a retaining bolt. Welborn explains that the lowside gauge insert will cause hole deviation (inclination) and the spring-loaded shoe will resist the tendency for bit-walk. He claims an improvement to the bearings within the mandrel, which reduces the tendency of the bearings to fail. The disclosure states that the gauge insert is chosen to obtain a particular change in inclination and that the shoe may be used (or left off) to correct bit-walk to the right. If a change in bit-walk rate occurs or if the bit tends to move to the left, then this tool, like the other tools described, must be withdrawn. This necessitates a round trip.
Thus, the prior art can correct bit-walk in a wellbore. However, if changes in the forces that cause bit-walk occur while drilling, all the prior art tools must be withdrawn in order to correct the direction of the wellbore. The absolute requirement for tool withdrawal means that a round trip must be performed. This results in a compromise of safety and a large expenditure of time and money. The industry needs a true lefl/right downhole tool that can remain in place on the downhole assembly and have its effect switched from the surface. That is, a tool that will cause the wellbore to turn either to the right or to the left whenever required.

Surface controlled wellbore directional steering tool


A network management application provides notification of events on network devices using prepopulated notification rules. The notification rule is prepopulated by the network management application using conditions that represent the present state of the device being monitored. An associated notification action is executed when an event on a network device satisfies the conditions of the prepopulated notification rule. The notification action can be tested without actually creating a set of conditions for a device that satisfies the conditions of the notification rule.

Not applicable.
1. Field of the Invention
The present invention relates generally to computer network management and more particularly to automatically defining conditions under which a user is notified of network activity.
2. Description of the Related Art
Network management has experienced explosive growth and become a fundamental part of network infrastructure. Network management is essentially a set of tools and processes that enables one to control, monitor, and troubleshoot a network. A network manager typically uses standalone or integrated network management software to collect and process management data from the network.
One of the functions served by network management software is the monitoring (or health polling) and notification of the state of various network devices. The state of a monitored device is reported, for example, as an entry in an event log dialog. As the use of network systems has grown, so too has the size of the networks. As such, many network systems are very complex. Likewise, network management for these large systems can be very complex. To provide a manageable interface, the network management software may be configured to report only changes in the state of a device. To further streamline reporting performed by network management software, a notification rule may be created to report only certain instances or severities of particular network changes.
A notification rule is a description of a type of event, or set of conditions, that triggers a notification. The notification rule tells the network management software when to notify a user or an administrator of an event. Generally, a notification rule is defined by a set of conditions relating to the device being monitored. These conditions may describe the present state of a device. Some event information that has been used to define notification rules are device types, alarm event types and alarm severity classes.
For example, a notification rule can be based in whole or in part on an alarm threshold condition to indicate when a network device, monitored by the network management software, exceeds or exits a certain operating state for that device. A rule for a network router device can be triggered using an alarm threshold set for monitoring the number of dropped or lost data packets. The alarm and subsequently the notification rule, is triggered when the number of dropped data packets exceeds the preset threshold. In addition, a corresponding alarm severity class can be set to limit triggering of the notification rule based on the extent to which the threshold had been exceeded. Alarm severity classes, for example, have included cleared (or informational), indeterminate, minor, major and critical alarm classes. For example, a number of dropped data packets only slightly exceeding the alarm event threshold is represented by a xe2x80x9cminorxe2x80x9d alarm, while a number of dropped data packets greatly exceeding the threshold is represented by a xe2x80x9ccriticalxe2x80x9d alarm. In addition, an xe2x80x9cinformationalxe2x80x9d alarm severity class has been established to provide information for devices not exceeding normal operating conditions.
Typically these notification rules have been created by a user or a network administrator. Much like the network systems they were designed to monitor, the notification rules have become increasing complex. Specifically, the user must step through a number of procedures to properly configure a notification rule for a particular device or a particular state of a device. Specifically, each of the event conditions included in a notification rule required that a user first retrieve the information describing the condition from somewhere within the network management software application. Next the user was required to manually enter in the relevant information into the notification rule. Finally, to complete the notification process, the user was required to specify a particular notification action that would be performed when the conditions defining the notification rule had been satisfied.
To further complicate the process, a number of alarm event and alarm severity combinations can be used. Typically, the combination of conditions for a particular notification rule was selected by taking the present state of a device. Specifically, the network management software would indicate the occurrence of an event for a device on the network and display such on a monitor at its location on the network server. An administrator then would typically desire that he be notified in the future upon subsequent like changes in the state of that particular device. Therefore, the notification rule would be created based on the set of conditions defining the state of the device in question.
The notification rule would include, a notification action specified by the administrator. These notifications actions included, for example, executing a script at the server location, reporting the particular event occurrence on a separate event log saved in the network management software, indicating a change in the state of the device by creating a sound on the host computer, sending an e-mail to a remote e-mail address, and sending a page to a remote receiver, for example the administrator""s pager. Any of these notification actions, or any combination thereof, would be performed by the network management software when the state of the monitored device matched the particular state upon which the notification rule conditions were based.
Configuring notification rules was time consuming, requiring a user or an administrator to manually configure all the information needed to define the notification rule. In addition, the administrator was usually left with no real way to test the specified notification action. In this way, upon creation of a notification rule, an administrator was unable to test the action without actually causing the event conditions that triggered the notification action to occur. A network administrator was, forced to either skip testing the notification to see if its effect is what is intended, or forced to attempt to create the event artificially to test the notification. Under many critical situations, creating an actual network problem may be undesirable from a systems standpoint, if not altogether impossible.
A system according to the present invention provides automatic notification of an event caused by a change in the state of a device connected to a network. A device, such as a network server, is monitored for activity. The present state, at any given time, is reported to a network management application. The application executes a notification action when the device activity satisfies a set of predetermined conditions, collectively termed a notification rule.
A system according to the present invention allows automatic prepopulating of the conditions comprising notification rule with the present state or set of conditions of a network device, as reported by the monitoring function. This simplified procedure avoids time-consuming manual searching of present device conditions and subsequent manual entry of these conditions into a notification rule. The notification rule functions as the trigger mechanism for a notification action. The notification action reports the occurrence of the event to the user in a manner specified by the user.
In addition, the present invention allows the notification feature to be easily tested by simulating the trigger for the notification action. The testing capability is performed without actually creating an event on the monitored device to trigger the conditions of the notification rule.

Automatic notification rule definition for a network management system

Compaq Information Technologies Group, L.P.


The purpose of the present invention is to provide a method for producing an oligosiloxane and an oligosiloxane synthesizer, by which an oligosiloxane can be efficiently produced. An oligosiloxane can be efficiently produced by the method for producing an oligosiloxane, which includes a condensation step for generating a hydrosiloxane having a structure represented by the following Formula (d) by reacting an alkoxysilane having a structure represented by the following Formula (b) with a hydrosilane having a structure represented by the following Formula (c) in the presence of a boron compound having Lewis acidity, and a hydrosilylation step for generating an alkoxysiloxane having a structure represented by the following Formula (f) by reacting the hydrosiloxane having the structure represented by Formula (d) generated in the condensation step with a carbonyl compound represented by the following Formula (E) in the presence of a boron compound having Lewis acidity. Moreover, an oligosiloxane having arbitrary substituent sequences can be produced.

Siloxane bonds constitute the main skeleton of silicone polymers and functional siloxane compounds, and thus methods for forming siloxane bonds have been actively developed since olden times. However, techniques for synthesizing oligosiloxanes through control over siloxane sequences are limited.
Masamune et al., have achieved stepwise synthesis of siloxane dendrimers through combination of siloxane bond formation by condensation reaction of silanol and chlorosilane in the presence of pyridine with dehydrogenative condensation of hydrosilane and water (see Non-patent Document 1). Meanwhile, Kung et al., have also reported a technique for synthesizing sequence-controlled oligosiloxanes, wherein siloxane bond formation by condensation reaction of silanol and chlorosilane is applied to perform stepwise reaction of silanediol and dichlorosilane (see Non-patent Document 2). However, the availability of silane monomers (chlorohydrosilane and silanediol) to be used for the above reactions is limited and a procedure of removing pyridinium chloride generated after the siloxane bond formation is required. Accordingly, rapid and convenient synthesis of various sequence-controlled oligosiloxanes by these techniques is difficult.
Meanwhile, tris(pentafluorophenyl)borane is known to catalyze the condensation reaction of alkoxysilane and hydrosilane (Patent Document 1 and Non-patent Document 2). Furthermore, this catalyst is also used for hydrosilylation of carbonyl compounds (Non-patent Document 3).

Sequence-controlled oligosiloxane and manufacturing method and oligosiloxane synthesizer therefor

NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE AND TECHNOLOGY


An image forming apparatus into which applications are installable includes an operation panel and a resolution comparing circuit. The operation panel has a display resolution. The resolution comparing circuit compares the display resolution with resolution of an application screen that an installed application displays. If the resolution comparing circuit determines that the display resolution is higher than the application screen resolution, the image forming apparatus displays the application screen as a screen provided with a frame.

Unless otherwise indicated herein, the description in this section is not prior art to the claims in this application and is not admitted to be prior art by inclusion in this section.
According to the latest technology, a typical image forming apparatus, which is a printer, a multifunction peripheral (MFP), or similar apparatus, ensures simplify installing an additional application convenient for a user. To execute the identical application on image forming apparatuses having operation panels with different resolutions, a known image forming apparatus causes an application to determine the resolution of the operation panel so as to switch screen data for displaying an application screen corresponding to the resolution. However, in the known image forming apparatus, every time a new image forming apparatus with a different resolution is released, it is necessary to revise the logic of the application so as to execute the application using the operation panel of the new image forming apparatus.

Image forming apparatus and method for displaying application screen of image forming apparatus that ensures display of application screen on operation panel with different resolution


A net guide for a wire screen, made to absorb an impact by causing connections of many guide pieces of a net guide formed by the connections of the guide pieces to have a stretchability. A net guide going in and out from a lower end of a movable frame in compliance with an opening/closing of a net to thereby guide a lower end of the net is constituted by connecting, by a wire, many guide pieces formed approximately like a U-letter by a bottom part and a standing wall part. The wire is inserted through through-holes of the guide pieces, and the guide pieces under a connected state are pressed by a coil spring giving a tension to the wire.

In the wire screen in which the net is made openable/closable by the lateral pull, the net guide which goes in and out, in compliance with an opening-and-closing of the above net, from the lower end of the movable frame or the fixed frame, that is attached to both ends of the net, to and from its inside, and which is introduced out along the lower end of the net concerned under the stretched state to thereby guide that lower end, is hitherto publicly known as disclosed in Patent Document 1 or Patent Document 2 for instance.
The net guide described in the above Patent Document 1 is one which is constituted from plural resin-made guide pieces formed approximately like a U-letter by a bottom part along the lower end of the net and a standing wall part which stands up along an outer face of the net concerned, and a flexible tape-like member for connecting those guide pieces, and in which the guide pieces are connected by inserting the above tape-like member through an insertion part, of the above tape-like member, provided along bottom parts of the guide pieces, and fixing the guide pieces in both ends to the tape-like member concerned.
On the other hand, in the above Patent Document 2, there is disclosed one in which the above net guide is constituted as a connection-like body connected in order by a fitting between a protrusion and a hole in a rigid unit.
However, as to the net guides of the above Patent Documents 1 and 2, in both of them, since there is made such that the net guide can be bent in order to introduce it from the lower end of the movable frame or the fixed frame to its inside but cannot be bent in other direction, there has been an issue that if a foot or other thing is caught by the net guide introduced-out to a lower part of the net and a strong force or impact acts on it, the net guide is simply disassembled or damaged.    Patent Document 1: JP-A-2003-201796 Gazette    Patent Document 2: JP-A-2000-145314 Gazette

Net guide for wire screen and wire screen apparatus having the same


Regular burst signals from video line (n+0) to line (n+3) are replaced by modified burst signals which function as copy prohibit signals. The phase of the modified burst signals is controlled by controlling at least one of the orthogonal vectors into which the phase of the regular burst signal is resolved; and the phase vector of the modified burst signals is equal to the average value of the phase vector of the regular burst signals in lines (n+0) through (n+3). The phase vector of the modified burst signal in line (n+2) exhibits a phase difference of 135.degree. from the phase vector of the original regular burst signal in that line and causes image disturbances when the thus-modified video signal is recorded and reproduced by a VCR. The phase vector of the modified burst signal in each of lines (n+0), (n+1) and (n+3) exhibits a difference as small as 45.degree. from the phase vector of the original regular burst signal in those lines.

This invention relates to copy protection to selectively prohibit the recording (i.e., copying) of analog video signals output from video discs, digital VCRs, digital broadcasting receivers, computers or other digital devices, yet permits satisfactory display by TV receivers of the original copy-protected video signals.
With the development of digital technologies, it has become easier and more commonplace to provide high-quality video signal sources for consumer use. For example, digital broadcasting terminals and DVDs (digital video discs) provide users with high-quality video signals and constitute such high-quality video sources. Digital VCRs (video cassette recorders) are gradually increasing their share of consumer use. Currently, however, analog VCRs are much more popular, and providers of high-quality video sources must take into account the coding or processing of digital video signals so as to restrict or prohibit the copying by analog VCRs of the analog version of digital video signals in order to protect the copyright of such video signals.
There are known techniques for prohibiting copying by analog VCRs known as, for example, the AGC pulse system and the color stripe system. The AGC pulse system restricts or prohibits copying of an analog video signal by inserting pulses having an amplitude larger than the normal AGC reference level typically recognized by the AGC circuits of the analog VCR. That is, pseudo sync pulses are inserted in some of the vertical blanking periods of the video signal, as shown in FIG. 21A. FIG. 21B is an enlarged view of a line interval in the blanking period in which the pseudo sync pulses are inserted. The pseudo sync pulses may comprise five cycles of a pulse of level p added to the horizontal sync pulse. Thus, the usual AGC reference level, measured as the level of the horizontal sync pulse, is increased by p.
Many types of analog VCRs (such as consumer-use analog VCRs) are configured to perform the AGC operation by using the horizontal sync pulse in a 1H line interval in the vertical blanking period, as shown in FIG. 21C. In these VCRs when the pseudo sync pulse having a larger amplitude than the horizontal sync pulse is inserted in the 1H line interval, the AGC circuit executes its AGC operation on the amplitude of the pseudo sync pulse as if the pseudo sync pulse is the reference level. As a result, the gain of the AGC circuit is erroneously thought to be too large and, accordingly, is decreased so as to be too small to detect the sync signal and to normally reproduce the video signal. TV monitors, however, use an AGC system that differs from that of analog VCRs and can adequately display reproduced images notwithstanding the pseudo sync pulses.
However, those video cassette recorders having long AGC time constants, such as .beta.-system VCRs, 8 mm VCRs and some VHS-system VCRs, are not particularly sensitive to pseudo sync pulses. To account for this, the color stripe system has been proposed. In the color stripe system, the phase of the color burst signal in the reproduced video signal is inverted for N-out-of-M lines; for example, 4 out of 21 lines.
TV monitors use APC (automatic phase control) for extracting color burst signals from the video signal (more particularly from the chroma signal). The phase of the color burst signal is detected and phase changes are integrated by a low pass filter, for example, to control a voltage controlled oscillator to generate a reference subcarrier for color demodulation of the input video signal. The reference subcarrier is also used as a reference signal for phase detecting the burst signal.
When a video signal processed by the color stripe system is recorded on another consumer-use analog VCR, the APC circuit of the analog VCR erroneously recognizes the phase-inverted color burst signal as if it is the original color burst signal. This results in inverting the color of the line when that video signal is reproduced. As a result, color-inverted lines appear in the displayed image every 21 lines, as shown in FIG. 22.
On the other hand, typical TV receivers use long time constant APC circuits having a narrow frequency response range for generating the reference subcarrier wave for color signal demodulation, so that the reproduced images are not affected when the color burst signals in only four lines are inverted. However, for those APC circuits that exhibit a long time constant but a wide frequency response range, color-inverted lines may appear in the displayed image.
In view of this, the assignee of the present invention has proposed that for all lines in an effective image display, the phase of only a certain period of the burst signal is inverted. This prevents deterioration of the quality of images even with TV monitors that exhibit color-inverted lines when using the color stripe system.
In consumer-use analog VCRs, the color subcarrier of frequency of 3.58 Mhz (in case of NTSC) is frequency-converted into a low-band-converted color signal having a center frequency in the range of 600 to 700 kHz. The low-band-converted color signal is frequency-multiplexed with a luminance signal and recorded on magnetic tape. When the video signal is reproduced, the low-band-converted color signal is frequency-separated and converted into a color signal having the original carrier frequency. Consequently, because of such recording/reproducing processing and the characteristics of the electromagnetic elements (e.g., tape, heads, etc.), the color signals in consumer-use analog VCRs are limited to a much narrower band than TV receivers. Because of this narrow band of the color signals, the duration of the reproduced color burst signal tends to expand relative to the duration of the original signal prior to recording. FIG. 23A shows the color burst signal in an original signal and FIG. 23B shows the expanded color burst duration in the signal reproduced by the VCR. The original color burst signal a shown in FIG. 23A is expanded to a' as shown in FIG. 23B when recorded on and then reproduced from the magnetic tape.
This inherent characteristic is used in the above-mentioned proposal by the assignee to invert the phase of only a few cycles of the color burst signals to prohibit copying. FIGS. 24A to 24C show an example of this proposal. For normal lines, the color burst signal extends over 10 cycles, for example (FIG. 24A). In some lines, however, in order to induce image disturbance for copy protection, 13 cycles of the color burst signal are provided, including 6 cycles of the phase-inverted color burst signal and 7 cycles of the normal phase color burst signal (FIG. 24B). For example, a block of 21 lines includes 17 lines with regular (i.e., normal phase) color burst signals and four lines with inverted color burst signals, these blocks being repeated throughout the image (FIG. 24C). When this type of copy-protected video signal is reproduced, the APC circuit in the color sync circuit of the VCR cannot follow the burst signal. As a result, the quality of the image displayed from the copied signal is deteriorated, and copying of the signal is prevented. However, TV monitors detect and use the normal phase color burst signals to display substantially normal images from the original, non-copied, copy-protected video signal.
This type of copy protection relies on VCRs that record color signals having narrow frequency bands and is not very effective in S-VHS analog VCRs, for example, in which the color subcarrier extends over a wide band. To overcome this problem, it is suggested to increase the number of cycles of inverted color burst signals in the burst interval. FIG. 25 shows an example in which the 13 cycles of burst signal include 10 cycles of inverted phase and three cycles of regular (i.e., normal) phase. This assures the copy prohibit function even with VCRs that record with wide band color signals. However, depending on the TV monitor, images displayed thereby may be unacceptably deteriorated. For example, even when no phase inversion of the burst signal occurs, images may be distorted by displaying a difference in color saturation resulting in horizontal stripes or by changes in color saturation over the entire image.
The present inventor attempted to overcome this problem of different color saturation by proposing blocks of copy prohibit signals formed of lines containing copy prohibit signals with a larger number of inverted color burst signals alternating with lines containing increased amplitude of regular color burst signals. Here the repetitive frequency of regular-phase color burst signals increases beyond the frequency response range of TV monitor APC circuits, thereby preventing or at least minimizing image disturbances caused by inverted color burst signals. Since normal phase color burst signals of increased amplitude are used, the decrease in cycles of regular color burst signals (caused by an increase in the number of cycles of inverted color burst signals) is compensated, and image disturbances on the TV monitors are prevented. On the other hand, when these copy-protected signals are copied and reproduced by VCRs, image disturbances are generated as a result of the expansion of the inverted color burst signals (FIG. 23B).
As known, TV monitors use an ACC (automatic color correction) circuit for automatic correction of color signal levels or amplitudes. The ACC circuit may use diode detection or phase detection, the output of which is integrated. When the ACC circuit uses phase detection, the above copy-protection method causes a substantial decrease in the color burst signal levels due to a cancellation of the integrated value of the detected inverted color burst signals because the inverted color burst signals are substituted for the regular color burst signals. However, since only some of the cycles of the color burst signals are modified (i.e., phase inverted), they compensate for the decreased level, and cancel the image disturbing function.
When the ACC circuit uses diode detection, phase information does not affect the detector output; for example, inverted color burst signals do not significantly affect the detector output but, rather, the inverted color burst signals result in overcorrection and cause image disturbance. A problem of ACC circuits is that their operating characteristics vary with different TV monitors so that the amount of correction that is needed is not determined definitely. Therefore, when a TV monitor is supplied with a signal containing such copy prohibit signals, it uses a fixed value to effect correction against the disturbance and residual errors may be detected as a disturbance. To overcome this problem, the inventor proposed a method of using inverted color burst signals and regular color burst signals of increased amplitude in a single horizontal line; and permitting the user to modify the amplitudes of the color burst signals as desired. If overcorrection by burst signals of increased amplitude occurs, image disturbance can be removed from TV monitor displays by appropriately setting the amplitude of such color burst signals.
While this method is effective when a video signal is supplied to a single TV monitor, it may be ineffective when the video signal is supplied to two or more monitors. For example, when two or more TV monitors are supplied from a single video output, it is difficult to effect appropriate corrections in all monitors to remove fully the disturbance in the display. This problem also occurs when a single TV monitor has a multi-screen display, such as a main screen and a sub-screen (e.g., picture-in-picture). In this case, since the sub-screen displays an image of the main screen in smaller size, the single monitor has separate circuits for processing the signals for the main screen and the sub-screen; and elements used in the respective circuits often are based on different standards. This may result in different characteristics of the ACC circuits and the APC circuits in the main screen and the sub-screen. Consequently, even after an appropriate setting is made for one, image disturbances may occur when the image displayed on the main screen is switched to the subscreen.


The present invention provides a system and method for promoting a probationary member to a full member in a distributed system. A probationary member includes a process in a distributed system that is intended to be added or intended to replace an existing process in the system. Prior to adding or replacing the probationary member, the probationary member is evaluated based on criteria associated with context information related to the system. Based on the evaluation, the probationary member may be promoted to a full member of the system or eliminated from the system. Therefore, the present invention provides the opportunity to evaluate the probationary member in the system, prior to the probationary member being promoted to a full member of the system. Additionally, the probationary member may be added or replace an existing process in a single view change. Therefore, fault tolerance is maintained when the probationary member is replacing a mirror in a fault-tolerant distributed system.

In recent years, reliable, high performance computer systems have been, and still are, in great demand. Users have also demanded the introduction and propagation of multi-processor distributed computer systems to support their computing processes (e.g., simulations, parallel processing, etc.). A distributed computer system generally includes a collection of processes and a collection of execution platforms (i.e., hosts). Each process may be capable of executing on a different host, and collectively, the processes function to provide a computer service. A failure of a critical process in a distributed system may result in the service halting.
Typically, each process in a distributed system maintains information, which may be updated, regarding the configuration of the system as a whole. To this purpose, processes often maintain a "view", which is a data structure representing the membership of the distributed system (i.e., a set of processes that constitute the system, and each process in the view is a member). It is often required that each process maintains a view consistent with the view maintained by the other processes in the system. All the processes in the system monitor the health of one another, for example, by sending heartbeats on network or internal communication links. This monitoring ability allows each process to update its view of which processes in the system are operational. Additionally, the processes in the system may communicate with each other for maintaining consistent views of the system.
A view change is a representation of membership that reflects the addition of a new member (i.e., a new process) or the removal of a current member from the view. For example, if the first process suspects that another process has failed, the first process can request a view change. Commonly, a technique for maintaining consistency between the processes includes the processes in the system voting on a view change. The majority of the members of the system must vote for a new view for it to be adopted.
A simple example of a distributed system is discussed herein to illustrate these concepts. One technique for minimizing the risk of a failure of a critical process in a distributed system includes implementing a fault tolerant system. A simple fault tolerant system may include three processes. Two of the processes are mirrors that provide system redundancy, which makes the system fault tolerant. If one mirror fails, the other has the ability to perform the role of the failed mirror in the system. A third process (called the "witness") is not a mirror and acts as a tie-breaker for view-consensus algorithms. If the third process agrees to a view change presented by one of the mirrors, the view change may be adopted by the system.
A distributed system may include members that have specific "roles". In the above example, two members may be mirrors of each other and provide users with a service, and the third witness-member may perform the function of maintaining view consistency.
While fault tolerant systems typically replace members due to the failure of a process, it may be desirable to replace a member that has not failed, hereafter referred to as the "victim". A victim may be used for the following situations: when the system is reconfigured to optimize performance; when a failed communication path requires a new process to be added via another communication path; when a host is removed from service for maintenance purposes, and the like.
A process may be replaced by killing the victim, which causes the system to repair itself by automatically replacing the victim. FIG. 5 illustrates a conventional method for killing a victim and merely relying on the system to replace the lost process through conventional failure detection and auto-repair ability.
In FIG. 5, view 505 illustrates normal operation of a three member system 500, including members (e.g., processes) 510, 520 and 530. Members 520 and 530 are mirrors. View 540 illustrates a first view change, including the removal of member 530. In view 540, member 530 is terminated (i.e., the victim is killed) and then removed from the view. In view 540, the system 500 is no longer fault tolerant, because no mirrors are available. Therefore, if member 520 fails, the computer service provided by system 500 may be halted. View 560 includes a second view change. In view 560, a new member 550 is added to the system for replacing member 530.
The process illustrated in FIG. 5 is "non-atomic", because more than one view change is required to replace a process. Because the system requires all three members in order to remain tolerant of failures, system 500 will not be fault tolerant during the interval after the victim has been killed and before the victim has been replaced. This temporarily exposes system 500 to the risk of system failure and halt in service. To avoid this risk, it is desirable to create a replacement member before killing the victim.

Adding and removing processes in a single view

Hewlett-Packard Development Company, L.P.


An integrated fracking system may include a substructure assembly including one or more frame rails. The integrated fracking system may include a variable frequency drive (VFD) coupled to the frame rails of the substructure assembly. The integrated fracking system may include a transformer coupled to the frame rails of the substructure assembly. The integrated fracking system may include a pump subsystem. The pump subsystem may include a first frac pump, a first motor operatively coupled to the first frac pump, a second frac pump, and a second motor operatively coupled to the second frac pump. The pump subsystem may be coupled to the frame rails of the substructure assembly.

Hydraulic fracturing, referred to herein as fracking, is a method used to enhance hydrocarbon recovery from certain downhole formations. Fracking involves the injection of high-pressure fluid into the downhole formation to induce fracturing of the formation. A proppant is typically included in the fluid used for fracturing. The proppant enters the fractures and retards the closure of the fractures once the fracking operation is completed. The fractures produced may provide additional flow channels for hydrocarbons to escape the formation.
Multiple pieces of wellsite equipment are used during a fracking operation including pumps used to supply the fracturing fluid to the formation, referred to herein as frac pumps. Frac pumps are typically driven by diesel motors. Frac pumps require the use of multiple other pieces of wellsite equipment to function, each of which must be operatively coupled in order to undertake a fracking operation.


A bicycle roller training system of the type having three rollers for supporting a freestanding bicycle uses rollers of a novel design. The rollers comprise a cylindrical middle portion of a uniform first diameter, two end portions of a second diameter larger than the first diameter, and two transitional portions between the middle portion and the end portions. The length of the middle portion is greater than the tread width of a tire of a bicycle with which the apparatus is used. The transitional portions increase in diameter from the cylindrical middle portion toward the ends of the roller. The transitional portions preferably have a curvilinear profile, and the preferred profile of the transitional portions is a parabolic curve. Thus the transitional portions preferably comprise paraboloids of revolution. The rollers also have disk-shaped weights mounted at one or more ends for increased angular momentum. Axles of the rollers are rotatably mounted to a frame. One or more steps may be provided on the frame for convenience in mounting the bicycle.

The present invention relates to the field of bicycle training apparatus; more specifically, it relates to roller system bicycle trainers.
A conventional bicycle roller system is a training device for bicyclists typically consisting of three parallel cylindrical rollers supported horizontally in a frame. One roller is positioned below the front wheel of the bicycle and two are positioned below the driven rear wheel. The two rear rollers are placed such that the rear wheel is cradled between them and in contact with both rear rollers at once. The front roller is linked to one of the rear rollers so that when a bicycle is ridden upon the system, both wheels of the bicycle spin at the same speed and impart stability to the bicycle via gyroscopic inertia. Such a bicycle roller system is described in U. S. Pat. No. 581,835 to Sturgis. This inertia allows the bicycle to be maintained in an upright position, but does little to limit lateral movement on the roller system. Minimal deviation of the front wheel from a straight-ahead orientation or a slight shift of the bicycle rider""s weight, causes relatively large lateral movement of the bicycle as compared to a bicycle on the ground. This potential for lateral movement and its sensitivity to rider input make rollers an excellent training device to improve bicycle handling skills, but severely limit their use for cardiovascular fitness. The average rider is constantly at risk of riding off the side of the rollers, as is an accomplished bicyclist should he become fatigued and lose concentration while riding. One solution to the problem of riding off the sides of the rollers is described in U.S. Pat. No. 463,862 to Guignard which employs concave rollers. Concave rollers in which the concavity is minimal (i.e., rollers having a shallow curvature) offer little aid in keeping the bicycle centered upon the roller. Concave rollers in which the concavity is severe (i.e., rollers having a deep curvature) reduce the skill-training benefit of rollers, while giving the sensation of riding down into a groove in the ground.
In addition, the uniform diameter rollers used by most conventional systems, carry little angular momentum. Thus, when the rider stops pedaling, the wheels stop in a matter of seconds and all gyroscopic-inertia helping to balance the bicycle is lost. This makes dismounting without falling difficult. A solution to the de-mounting problem is described in U.S. Pat. No. 3,905,597 to Tabb, which describes elevated and inwardly slanted platforms located adjacent to the pedaling region and positioned to be readily reached by the feet of the bicycle operator when the bicycle is in an upright operating position. However, the presence of such platforms can in itself present additional safety and convenience problems.
Because of the above difficulties, bicycle roller use is usually limited to skill training by accomplished riders.
This patent describes a bicycle roller system of the three-roller type, using rollers of a novel design. Each of the rollers comprises a xe2x80x9cflatxe2x80x9d (right-cylindrical) middle portion or central span of a first diameter, two end portions of a second diameter larger than the first diameter and two transitional portions, which are between the middle portion and each of the end portions. The transitional portions increase in diameter from the middle portion toward the ends of the roller. The transitional portions preferably have a curvilinear profile and an identical profile at both ends of a roller. The most preferred rate of increase of diameter of the transitional portions is a parabolic rate; i.e., the diameter is a parabolic function of distance measured along a direction parallel to the roller axis. Another equivalent way of characterizing the preferred shape of the transitional portion is to define it as paraboloidal. The rollers also preferably have disks of a relatively high density mounted at one or more ends as disk-shaped weights. The middle portion or central span of each roller, being of uniform diameter, allows skill training and as realistic a feel as on a system employing conventional flat rollers. The parabolic rate of increase in the diameter of the transitional portions of the rollers yields multiple benefits. First, the transitional portions impart a centralizing force to the bicycle tires when the tires leave the central span. This centralizing force increases the closer the tires come to the end of the roller, making it difficult to ride off the rollers. At a given rotational speed, the roller having a disk-shaped weight affixed at the end of the roller has greater angular momentum than a standard unweighted roller of lesser diameter, without requiring the entire roller to be of large diameter and without requiring massive weight to be used in small diameter rollers. The increased angular momentum or flywheel effect allows a rider to coast on the rollers, simulating actual ground riding. The flywheel effect also allows a rider time to start dismounting, i.e., to disengage his foot from a bicycle pedal and place the foot upon the supporting surface mounted under the bicycle, before the gyroscopic-inertia from the spinning wheels, which helps balance the bicycle, is lost. The rate of increasing diameter of the three rollers transitional portions can vary, even within a single system, as can the widths of the rollers and the widths of the xe2x80x9cflatxe2x80x9d middle portions. Specifically, if the transitional portions"" diameters vary in the preferred parabolic manner, the parabolic rates of increase of the diameter of the transitional portions can vary


A seat belt buckle for use with a tongue of a seat belt includes a latch that engages the tongue, and a release bar that releases the latch. An inertia locking device mounted to a frame portion is normally biased in an unlocking position and rotates to a locking position to prevent movement of the release bar into the release position when the seat belt buckle is subjected to a force greater than the biasing force.

Seat belt buckles in general must meet many requirements to reliably operate under any and all conditions. One specific requirement for seat belt buckles is to function when used with seat belt pretensioners (i.e., retractor, buckle or anchor pretensioners).
Seat belt pretensioners remove seat belt slack in the event of a predetermined occurrence. When pretensioners are activated this results in a very high acceleration of the seat belt webbing and subsequently the seat belt buckle.
Therefore, it is desirable to provide the seat belt buckle with a locking feature or device that is engaged during activation of the pretensioners.

Seat belt buckle for use with pretensioner


A foldable supporting assembly includes an inner lateral bar unit, and first, second, third and fourth longitudinal bar units. The first and second longitudinal bar units are disposed at a first side, and rotatably connected with the first and second ends of the inner lateral bar unit. The third and fourth longitudinal bar units are disposed at a second side, and rotatably connected with the first and second ends of the inner lateral bar unit. When folded, one of the first and second longitudinal bar units is disposed between the inner lateral bar unit and the other one of the first and second longitudinal bar units, and one of the third and fourth longitudinal bar units is disposed between the inner lateral bar unit and the other one of the third and fourth longitudinal bar units.

Beds are usually the main furniture in bedrooms and often occupy the majority of the space. In modern days, foldable beds become daily necessities in particular when the space is limited. Foldable beds are desirable because they are convenient to use and require less space for storage. However, some existing foldable bed frames, especially those double-layered frames (e.g., lateral or longitudinal bar unit made of a stack of bars), are not user-friendly. They cannot be folded well, and thus would take up a large space during transportation and storage.
Given the current state of the art, there remains a need for foldable beds and bed frames that address the abovementioned issues.
The information disclosed in this Background section is provided for an understanding of the general background of the invention and is not an acknowledgement or suggestion that this information forms part of the prior art already known to a person skilled in the art.

This patent is subject to a terminal disclaimer.

Foldable supporting assembly and bed frame having same


A thumb support (1) including a thumb engaging portion (3) and an anchoring portion (5). The thumb engaging portion (3) is attached to the anchoring portion (5) by means a first elastically extensible strap (7), such that the thumb is resiliently biased towards a preselected healing position. In a preferred embodiment, a second elastically extensible strap (9) is included which provides additional support.

The present invention relates to an apparatus for maintaining a user's thumb in a predetermined healing position.
Injuries to the thumb and adjacent muscles and ligaments commonly occur during many sports, including various types of football, basketball, cricket, baseball, and snow skiing. Such injuries can also occur during day-to-day activities through accidental falls or other mishaps.
The majority of these injuries involve damage to the ulnar collateral ligament of the metacarpal phalangeal joint (MCP joint) of the thumb, and may vary from minor sprains through to partial and complete tearing of the ligament. A complete tear requires immediate surgery, whilst other types of injuries may heal by themselves given adequate time and rest.
After injury or surgery, it is necessary to minimise strain on the ligament, thereby to promote faster and better healing. In the past, this has generally been achieved by means of standard bandages or taping. However, such measures require expert application, and moreover provide a relatively static support by binding the thumb against the adjacent hand.
There are available some splint and brace devices which are designed to immobilise the thumb in a particular position. One type utilises metallic or plastics splints within an elastic lycra or neoprene casing. In use, the splints lie along the outside of the thumb to maintain it in a particular position. Other types of splints are formed from rigid plastics materials designed to envelope the thumb.
A disadvantage of all these supports is that they tend to be cumbersome, and difficult to remove and apply, particularly if the wearer is in pain. Due to their passive nature, they do not enable use of the thumb in its usual capacity, and are not therefore able to be used as an injury prevention device. Furthermore, such splints generally fail to maintain the thumb in an optimal healing position as they often fail to position the thumb correctly.


The present invention discloses genetically engineered plants which display altered structure or morphology. The transgenic plants express a cell wall modulation transgene or gene construct that results in the altered structure or morphology. The altered structure or morphology can be associated with, for example, altered biomass, growth, yield, greater or less resistance to biodegradation, more or less digestible to ruminants, altered cellulose content, larger leaves/normal hypocotyls or smaller leaves/longer hypocotyls, etc. compared to a non-transgenic plant of the same species. The cell wall modulation transgene can be any cellulose binding domain, a cellulose binding protein, or a cell wall modifying protein or enzyme such as endoxyloglucan transferase, xyloglucan endo-transglycosylase, an expansin, cellulose synthase, or a novel isolated endo-1,4-.beta.-glucanase of Arabidopsis thaliana. The invention also discloses transgenic plants containing a gene construct comprising a promoter operably linked to the cell wall modulation protein or polypeptide gene and may further comprise a sequence encoding a secretion signal peptide. In particular, the invention discloses transgenic plants containing a gene construct comprising the cel1 promoter, operably linked to the cel1 signal peptide and any cellulose binding domain. Methods for modulating plant growth by transgenic expression of a cell wall modulating protein or polypeptide are also disclosed. The present invention also discloses a novel, isolated Arabidopsis thaliana endo-1,4-.beta.-glucanase gene (cel1), its promoter (cel1 promoter) and polypeptide (Cel1) and recombinant nucleic acid vectors containing the cel1 gene with or without a secretion signal peptide sequence and/or the cel1 promoter.

2.1. PLANT ELONGATION AND GROWTH
The plant cell elongation mechanism is a fundamental process with primary importance in plant-tissue development. Cell elongation requires relaxation of the rigid primary cell wall (Carpita and Gibeaut, 1993, Plant J. 3:1-30; Cosgrove, 1993, Plant Physiol. 102:1-6; Fry, 1988, The Growing Plant Cell Wall Chemical and Metabolic Analysis, Lonoman Scientific & Technical, New York; Roberts, 1994, Curr. Opin. Cell Biol. 6:688-694). Several mechanisms for this relaxation have been suggested, including the activities of endo-xyloglucan transferase (Nishitani and Tominaga, 1992, J. Biol. Chem. 267:21058-21064), xyloglucan endotransglycosylase (Fry et al., 1992, Biochem. J. 282:821-828) and expansins (McQueen-Mason and Cosgrove, 1995, Plant Physiol. 107:87-100). Endo-1,4-.beta.-glucanase (hereinafter, EGase) has been suggested to play an important role in the elongation process (Shoseyov and Dekel-Reichenbach, 1992, Acta Hort. 329:225-227; Verma et al., 1975, J. Biol. Chem.250:1019-1026).
Substantial evidence for the involvement of a 1,3-1,4-.beta.-glucan-specific enzyme in cell elongation was found in monocotyledons (Hatfield and Nevins, 1987, Plant Physiol. 83:203-207; Hoson and Nevins, 1989, Plant Physiol. 90:1353-1358 1989; Inouhe and Nevins, 1991, Plant Physiol. 96:426-431). EGase has been implicated in xyloglucan degradation during vegetative growth and fruit ripening (Hayashi, 1989, Ann. Rev. Plant Physiol. 40:139-168; Hayashi et al., 1984, Plant Physiol. 25:605-610). The activity of this enzyme could affect the generation of oligosaccharins, signaling molecules that are involved, among other things, in plant development and cell elongation (see for review, Darvill et al., 1992, Glycobiology 2:181-198).
To date, most of the EGase genes isolated have been studied in relation to fruit ripening (Cass et al., 1990, Mol. Gen. Genet. 223:76-86; Fischer and Bennett, 1991, Ann. Rev. Plant Physiol. Plant Mol. Biol. 42:675-703; Lashbrook et al., 1994, Plant Cell 6:1485-1493; Tucker et al., 1987, Plant Mol. Biol. 9:197-203) and abscission zones (Kemmerer and Tucker, 1994, Plant Physiol. 104:557-562; Tucker and Milligan, 1991, Plant Physiol. 95:928-933; Tucker et al., 1988, Plant Physiol. 88:1257-1262).
More recently, Wu et al. (1996, Plant Physiol. 110:163-170) cloned the EGase gene from pea and showed its expression to be induced by auxin in elongating epicotyls.
Endogenous regulation of cell elongation appears to be dominated by cell wall mechanics. This process is a result of the interaction between internal turgor pressure and the mechanical strength of the cell wall (reviewed by Steer and Steer, 1989, New Phytol. 111:323-358). Unlike most plant cells, the growth of pollen tubes and root hairs is restricted to the tip zone (reviewed by Cresti and Tiezzi, 1992, "Pollen tube emission organization and tip growth," in Sexual Plant Reproduction, pp. 89-97, eds. Cresti and Tiezzi, Springer-Verlag, Berlin). The growing region of pollen tubes consists of two distinct layers when fully mature. The inner layer consists mostly of callose-related molecules and the outer layer contains pectin, xyloglucan (XG), cellulose (at low levels and poor crystallinity) and other polysaccharides (reviewed by Steer and Steer, 1989, New Phytol. 111:323-358).
Xyloglucans (XGs) are linear chains of .beta.-(1-4)-D-glucan, but unlike cellulose, they possess numerous xylosyl units added at regular sites to the 0-6 position of the glucosyl units of the chain (reviewed by Carpita and Gibeaut, 1993, Plant J. 3:1-30). XG can be extracted by alkaline treatment and then bound again in vitro to cellulose (Hayashi et al., 1994, Plant Cell Physiol. 35:1199-1205).
XG is bound to cellulose microfibrils in the cell walls of all dicotyledons and some monocotyledons (reviewed by Roberts, 1994, Curr. Opin. Cell Biol. 6:688-694). The XG bound to the cellulose microfibrils cross-links the cell-wall framework.
Plant-cell expansion, including elongation, requires the integration of local wall-loosening and the controlled deposition of new wall materials. Fry et al. (1992, Biochem J. 282:821-828) and Nishitani and Tominaga (1992, J. Biol. Chem 267:21058-21064) purified xyloglucan endo-transglycosylase (XET) and endo-xyloglucan transferase (EXT), respectively. These two enzymes were shown to be responsible for the transfer of intermicrofibrillar XG from one segment to another XG molecule and thus, suggested to be wall loosening-enzymes.
However, McQueen-Mason et al. (1993, Planta 190:327-331) showed that XET activity did not correlate with in vitro cell all extension in cucumber hypocotyls.
The effect of XG on growing tissues has been extensively investigated. XG oligosaccharides, produced by partial digestion with .beta.-(1-4)-D-glucanase and referred to as "oligosaccharins", alter plant-cell growth (reviewed by ldington and Fry, 1993, Advances in Botanical Research 19:1-101). One such oligosaccharin, XXFG (XG9), antagonizes the growth promotion induced in pea stem segments by the auxin 2,4-D at a concentration of about 1 nM (York et al., 1984, Plant Physiol. 75:295-297; McDougall and Fry, 1988, Planta 175:412-416). On the other hand, at high concentrations (e.g,., 100 .mu.M) oligosaccharins promote the elongation of etiolated pea stem segments (McDougall and Fry, 1990, Plant Physiol. 93:1042-1048). The mode of action of oligosaccharins is still unknown.
Another type of cell wall-loosening protein, termed "expansin", was isolated by McQueen-Mason et al. (1992, The Plant Cell 4:1425-1433). Expansin does not exhibit hydrolytic activity with any of the cell-wall components. It binds at the interface between cellulose microfibrils and matrix polysaccharides in the cell wall, and is suggested to induce cell wall expansion by reversibly disrupting noncovalent bonds within this polymeric network (McQueen-Mason and Cosgrove, 1995, Plant Physiol. 107:87-100).
Some cellulose-binding organic substances alter cell growth and cellulose-microfibril assembly in vivo. Direct dyes, carboxymethyl cellulose (CMC) and fluorescent brightening agents (FBAs, e.g., calcofluor white ST) prevent Acetobacter xylinum microfibril crystallization, thereby enhancing polymerization. These molecules bind to the polysaccharide chains immediately after their extrusion from the cell surface, preventing normal assembly of microfibrils and cell walls (Haigler, 1991, "Relationship between polymerization and crystallization in microfibril biogenesis," in Biosynthesis and Biodegradation of Cellulose, pp. 99-124, Haigler and Weimer eds., Marcel Dekker, Inc., New York). Haigler discusses dyes and fluorescent brightening agents that bind to cellulose alter cellulose microfibril assembly in vivo. Modifications in cell shape were observed when red alga (Waaland and Waaland, 1975, Planta 126:127-138) and root tips (Hughes and McCully, 1975, Stain Technology 50:319-329) were grown in the presence of dyes. It is now evident that these molecules can bind to the cellulose chains immediately upon their extrusion from the cell surface of prokaryotes and eukaryotes (Haigler and Brown, 1979 Science 210:903-906; Benziman et al., 1980, Proc. Natl. Acad. Sci. USA 77:6678-6682; Haigler et al., 1980, Science 210:903-906; Brown et al., 1982, Science 218:1141-1142) and prevent crystal-structure formation (Haigler and Chanzy, 1988, J. Ultrastruct. Mol. Struct. Res. 98:299-311). In addition, the rate of cellulose polymerization was shown to increase in the presence of dye (Benziman et al., 1980). Crystallization was proposed to be the bottleneck in this coupled reaction and its prevention to result in accelerated cellulose synthase activity.
2.2. CELLULOSE BINDING PROTEINS AND DOMAINS
Many cellulases and hemicellulases (e.g., xylanases and mannases) have the ability to associate with their substrates. These enzymes typically have a catalytic domain containing the active site for substrate hydrolysis and a carbohydrate-binding domain or cellulose-binding domain (herein generally designated "CBD") for binding the insoluble cellulosic or hemicellulosic matrices.
To date, more than one hundred and twenty cellulose-binding domains (CBDs) have been classified into ten families designated I-X (Tomme et al., 1995, "Cellulose-Binding Domains: Classification and Properties", in ACS Symposium Series 618 Enzymatic Degradation and Insoluble Carbohydrates, pp. 142-161, Saddler and Penner eds., American Chemical Society, Washington, D.C.) (incorporated herein by reference). Most of the CBDs have been identified from cellulases and xylanases, but some are from other polysaccharides or from non-catalytic proteins. The CBDs identified thus far are from fungi, bacteria and slime molds.
The ten families of CBDs are as follows: family I CBDs are all from fungal .beta.-1,4-glycanases; family II CBDs are found in bacterial hydrolases; family III CBDs are found in .beta.-1,4-glucanases; family IV CBDs primarily have two conserved cysteine residues; family V is represented by a CBD from Erwinia chysanthemi; family VI CBDs are primarily from xylanases and nearly all located at the C-terminal end of the protein; family VII is represented by the CBD of Clostridium thermocellum; family VIII is represented by the CBD of Dictyostelium discoidum; family IX CBDs are all known to be present as tandem repeats at the C-terminal end of thermostable xylanases; and family X is represented by xylanase E from Pseudomonas florescens spp. cellulosa. For a detailed description of the CBD families and individual members useful in the present invention, see Table II of Tomme et al. which is incorporated herein by reference.
Shoseyov and Doi (1990, Proc. Natl. Acad. Sci. USA 87:2192-2195) isolated a unique cellulose-binding protein (CbpA) from the cellulase "complex" of the cellulolytic bacterium Clostridium cellulovorans. This major subunit of the cellulase complex was found to bind to cellulose, but had no hydrolytic activity, and was essential for the degradation of crystalline cellulose.
The cbpA gene has been cloned and sequenced (Shoseyov et al., 1992, Proc. Natl. Acad. Sci. USA 89:3483-3487). Using PCR primers flanking the cellulose-binding domain (herein, this specific CBD is designated "cbd") of CbpA, the latter was successfully cloned into an overexpression vector that enabled overproduction of the approximately 17 kDa cbd in Escherichia coli. The recombinant cbd exhibits very strong affinity to cellulose (U.S. Pat. No. 5,496,934; Goldstein et al., 1993, J. Bacteriol. 175:5762-5768; PCT International Publication WO 94/24158, all are incorporated by reference as if fully set forth herein).
In recent years, several CBDs have been isolated from different sources. Most of these have been isolated from proteins that have separate catalytic, i.e., cellulase and cellulose binding domains, and only two have been isolated from proteins that have no apparent hydrolytic activity but possess cellulose-binding activity (Goldstein et al., 1993, J. Bacteriol. 175:5762-5768; Morag et al., 1995, Appl. Environ. Microbiol. 61-1980-1986).
2.3. CLOSTRIDIUM CELLULOVORANS CBD EFFECTS ON SEEDLING AND POLLEN TUBE ELONGATION
The exogenous application of the cbd of Clostridium cellulovorans has been shown to modulate the elongation of pollen tubes and seedlings grown in culture. See PCT International Publication WO 94/24158 at pages 73-77.
The cbd of C. cellulovorans promoted pollen tube growth of peach pollen grains grown in liquid culture. Pollen grains exposed to 50 ug/ml of cbd produced pollen tubes almost twice size of pollen grains treated with bovine serum albumin (BSA) at 50 ug/ml.
Seeds of Arabidopsis thaliana germinated in distilled water in the presence of C. cellulovorans cbd responded differently to high versus low concentrations of cbd. High concentrations of cbd (1-100 ug/ml) dramatically reduced the root length. Low concentrations of cbd (1.times.10.sup.-6 to 1.times.10.sup.-4 ug/ml) promoted elongation of the roots whereas treatment with BSA had no effect. The effect on shoot length revealed a similar trend, but the differences between the treatments were not as dramatic as for the roots, and were not statistically different.
Cell walls of pollen tubes have been shown to contain exposed cellulose fibrils in the tip zone (reviewed by Steer and Steer, 1989, New Phytol. 111:323-358). Pollen tube elongation is known to be apical (reviewed by Cresti and Tiezzi, 1992, "Pollen tube emission, organization and tip growth", in Sexual Plant Reproduction, pp. 89-97, Cresti and Tiezzi eds., Springer-Verlag, Berlin). Gold-immunolabelling of cbd in pollen tubes revealed that cbd was present primarily at the tip zone. Moreover, the lack of calcofluor staining in the tip zone of cbd-treated pollen tubes indicated the absence of a crystalline structure. See PCT International Publication WO 94/24158.
It has already been established that XG chains cross-link the cellulosic network in the cell wall (reviewed by Roberts, 1994, Curr. Opin. Cell Biol. 6:688-694). It is accepted that a prerequisite for cell elongation is a loosening of the cross-linked cellulose network, by either hydrolysis as demonstrated by Inouhe and Nevins (1991, Plant Physiol. 96:426-431), transglycosylation (Fry et al., 1992, Biochem. J. 282:821-828; Nishitani and Tominaga, 1992, J. Biol. Chem. 267:21058-21064), or expansins that interact with the XG-cellulose bond (McQueen-Mason et al., 1992, The Plant Cell 4:1425-1433). By in vitro competition assays it was shown that cbd competes with XG for binding to cellulose. Maximum cbd binding to cellulose is achieved after 1 hour (Goldstein et al. 1993, J. Bacteriol. 175:5762-5768), compared to XG binding to cellulose that is achieved only after 4 hour (Hayashi et al. 1987, Plant Physiol. 83:384-389). It is suggested that, during the elongation process, cellulose microfibrils become exposed and cbd competes with XG on binding to the exposed cellulose microfibril. It is therefore possible that this competition results in a temporary loosening of the cell wall and consequently enhanced elongation.
The inhibitory effect of cbd on root elongation can be explained by steric hindrance of the cellulose fibrils by excess amounts of cbd, which block access for enzymes or other proteins that modulate cell elongation via loosening, of the rigid cellulose-fibril network. This hypothesis is supported by Nevins, who prevented auxin-induced elongation with anti-.beta.-D-glucan antibodies (Hoson and Nevins, 1989, Plant Physiol. 90:1353-1358) or with antibodies specific to cell wall glucanases (Inouhe and Nevins, 1991, Plant Physiol. 96:426-431).
The cbd of the CbpA protein of C. cellulovorans is a bacterial protein. Its mode of action in modulating cell wall elongation may be different from that of the natural process.

Arabidopsis thaliana endo-1,4-.beta.-glucanase gene and promoter

Yissum Research Development Company of the Hebrew University of Jerusalem


In some embodiments, the present disclosure relates to a plasma processing system configured to form a symmetric plasma distribution around a workpiece. In some embodiments, the plasma processing system comprises a plurality of coils symmetrically positioned around a processing chamber. When a current is provided to the coils, separate magnetic fields, which operate to ionize the target atoms, emanate from the separate coils. The separate magnetic fields operate upon ions within the coils to form a plasma on the interior of the coils. Furthermore, the separate magnetic fields are superimposed upon one another between coils to form a plasma on the exterior of the coils. Therefore, the disclosed plasma processing system can form a plasma that continuously extends along a perimeter of the workpiece with a high degree of uniformity (i.e., without dead spaces).

Integrated chips are formed by complex fabrication processes, during which a workpiece is subjected to different steps to form one or more semiconductor devices. Some of the processing steps may comprise formation of a thin film onto the semiconductor substrate. Thin films can be deposited onto a semiconductor substrate in a low pressure processing chamber using physical vapor deposition.
Physical vapor deposition is typically performed by acting on a target material to convert the target into a vapor. Often, a target material is acted upon by a plasma comprising a plurality of high energy ions. The high energy ions collide with the target material, dislodging particles into the vapor. The vapor is transported to a semiconductor substrate, upon which the vapor accumulates to form a thin film.

Taiwan Semiconductor Manufacturing Co., Ltd.


A fastening device for a vehicle area with at least one reception rail fixed to the vehicle has associated therewith an additional functional profile. The additional functional profile permits the binding of further components to the reception rail. In one embodiment, the functional profile includes a plastic envelope profile surrounding the reception rail. In a further embodiment, a fastening block is placed in the reception rail, and can be secured in the reception rail.

1. Field of the Invention
The invention relates to a fastening device for a vehicle area with at least one vehicle-fixed reception rail.
2. Description of Related Art
Such a fastening device is generally known in connection with cars. Thus, in particular vehicle seats in the vehicle interior are located in displaceable manner on reception rails. The reception rails are connected to a vehicle floor and are consequently fixed to the vehicle.
It is also known (DE 100 47 542 A1) to anchor several reception rails in a loading or luggage area or space of a car and said rails can be used for receiving and fixing functional components.
The problem of the invention is to provide a fastening device of the aforementioned type, which, with simple means, has high functionality.


A printed circuit board (PCB) defines a first outer surface and a second outer surface that is opposite the first outer surface. The first outer surface of the PCB defines a recess. The PCB includes a signal layer between the first outer surface and the second surface with a first portion exposed within the recess and a second portion exposed within the recess. A component is disposed within the recess and connected to the first portion and the second portion of the signal layer such that an entirety of the component is within the recess and below the first surface.

Embodiments described herein relate generally to the placement of electrical components on a printed circuit board, and more particularly, subsurface mounting of discrete electrical components on internal printed circuit boards layers.
Some known electronic devices manufactured for high-speed signal transfer (e.g., greater than 10 Gigabits per second Gb/s) use printed circuit boards (PCBs) having dielectric materials with specific characteristics. Often, such dielectric materials are configured to minimize losses, thereby facilitating the high-speed signal transfer. Such known dielectric materials are typically expensive, at times being five to seven times the cost of a standard, commonly used PCB substrate (e.g., FR-4). As such, the efficient use of space on the PCBs is desirable.
Often, such PCBs have differential pairs and/or impedance-controlled strips (e.g., a transmission line such as a microstrip and/or stripline) to minimize impedance mismatches that can result in signal degradation. In some known high-speed applications, it may be desirable to use, for example, serial capacitors (i.e., alternating current (AC) capacitors) to provide AC isolation between a transmitter component and a receiver component on a PCB. Such capacitors, however, can introduce a characteristic impedance mismatch into the circuit. As such, the PCBs often employ signal vias to provide connectivity to internal layers of the PCB, which generally are back drilled to reduce the via stub. Moreover, the signal vias can degrade signal quality by increasing loss and/or cross-talk, as well as having parasitic resonances. In an effort to minimize these effects, the PCBs often include several ground vias to provide return signal paths, improve characteristic impedance mismatches, and reduce or eliminate signal-via-to-signal-via cross-talk. The inclusion of several ground vias, however, reduces the usable space of the PCB (e.g., portions of signal layers below the AC capacitors often become unusable) and can often result in challenges with routing signal traces.
Thus, a need exists for improved apparatus and methods for placement of discrete electrical components on internal layers of a PCB to increase component density of the PCB.

Apparatus and methods for placement of discrete components on internal printed circuit board layers


A method for electroblowing fibers is provided which involves the steps of:                forcing a polymer fluid through a spinneret in a first direction towards a collector located a first distance from the spinneret, while simultaneously blowing a gas through an orifice that is substantially concentrically arranged around the spinneret, wherein the gas is blown substantially in the first direction;        wherein an electrostatic differential is generated between the spinneret and the collector; and        collecting the fibers, and its use in preparing submicron scale fibers of various types, particularly hyaluronan fibers, and the hyaluronan nanofibers thus formed.

1. Field of Invention
The present invention relates to a method for spinning nanofibers that combines aspects of electrospinning and melt-blowing, its application to spinning of hyaluronan and the nanofibrous materials made thereby.
2. Discussion of the Background
One technique conventionally used to prepare fine polymer fibers is the method of electrospinning. When an external electrostatic field is applied to a conducting fluid (e.g., a charged semi-dilute polymer solution or a charged polymer melt), a suspended conical droplet is formed, whereby the surface tension of the droplet is in equilibrium with the electric field. Electrospinning occurs when the electrostatic field is strong enough to overcome the surface tension of the liquid. The liquid droplet then becomes unstable and a tiny jet is ejected from the surface of the droplet. As it reaches a grounded target, the jet stream can be collected as an interconnected web of fine sub-micron size fibers. The resulting films from these non-woven nanoscale fibers (nanofibers) have very large surface area to volume ratios.
The electrospinning technique was first developed by Zeleny[1] and patented by Formhals[2], among others. Much research has been done on how the jet is formed as a function of electrostatic field strength, fluid viscosity, and molecular weight of polymers in solution. In particular, the work of Taylor and others on electrically driven jets has laid the groundwork for electrospinning[3]. Although potential applications of this technology have been widely mentioned, which include biological membranes (substrates for immobilized enzymes and catalyst systems), wound dressing materials, artificial blood vessels, aerosol filters, and clothing membranes for protection against environmental elements and battlefield threats[4-26].
The major technical barrier for manufacturing electrospun fabrics is the speed of fabrication. In other words, as the fiber size becomes very small, the yield of the electrospinning process becomes very low. For example, if one considers a polymer melt being spun from the spinneret with a diameter of 700 μm, and the final filament is formed with a diameter of 250 nm, the draw ratio will then be about 3×106. As the typical throughput of the extrudate from a single spinneret is about 16 mg/min (or 1 g/hr), the final filament speed will be about 136 m/s, as compared to the highest speed (10,000 m/min or 167 m/s) attainable by the high-speed melt-spinning process. Thus, the throughput of the spinneret in conventional electrospinning is about 1000 times lower than that in the commercial high-speed melt-spinning process.
Another major technical problem for mass production of electrospun fabrics is the assembly of spinnerets during electrospinning. A straightforward multi-jet arrangement as in high-speed melt spinning cannot be used because adjacent electrical fields often interfere with one another, making the mass production scheme by this approach impractical.
A unique esJets™ technology for multiple-jet electrospinning process has recently been developed for manufacturing of non-woven membranes having fibers with diameters in the tens of nanometers size range. Three patent applications based upon this technology have been filed[27-29] and several papers have also been published[30-34].
Hyaluronan (HA) is an associated polymer, having the following structure:

HA has an acidic group as well as a glucosamine segment. The presence of this weak acid makes the polymer a polyelectrolyte, i.e., its charge density depends on the degree of dissociation, that can be influenced by factors including, but not limited to:                pH        ionic strength        nature of co-ions and counter ions        solvent quality that shall also affect the above 3 conditions.
The degree of association can be disturbed by physical and/or chemical means. For example:                By physical means, e.g., ultra-sonics, shear, microwave, etc.        By chemical means, such as complex formation with a liquid, e.g., polyethylene oxide is soluble in water because of its hydrogen bonding with water.

Electro-blowing technology for fabrication of fibrous articles and its applications of hyaluronan

The Research Foundation of State University of New York


An updated part of map data is delivered while suppressing unwanted communication traffic and preventing contradiction in the updated map. A map delivering server (10) comprises a map data storage section (102) storing link data including the update dates and times and update infection range for each link, a network IF section (101) for receiving from a navigation terminal (20) a map delivery request containing the requested area of map delivery and the previous request data and time of map delivery of the requested area, and a map element search section (103) for searching the map data storage section (102) for the link data associated with the update infection range including the link at least a part of which belongs to the requested area of the map delivery request and associated with the update date and time later than the previous request date and time contained in the map delivery request. The link data found by the map element search section (103) is sent to the navigation terminal (20) through the network IF section (101).

Patent Document 1 and Patent Document 2 disclose techniques of delivering map data from a server to a terminal such as a navigation system on a basis of mesh cells. Patent Document 3 discloses a technique in which, when for instance a moving object is traveling on a new road unregistered in map data, a terminal mounted to the moving object sends coordinate data for identifying the road to a server and the server updates master map data using the coordinate data of the new road that has been sent from the terminal.
Patent Document 1: JP 2003-044992 A
Patent Document 2: JP 2004-077254 A
Patent Document 3: JP 2004-004240 A

Map data delivering device, communication terminal, and map delivering method


An integrated vertical SiC—PN power diode has a highly doped SiC semiconductor body of a first conductivity type, a low-doped drift zone of the first conductivity type, arranged above the semiconductor body on the emitter side, an emitter zone of a second conductivity type, applied to the drift zone, and at least one thin intermediate layer of the first conductivity type. The intermediate layer is arranged inside the drift zone, has a higher doping concentration than the drift zone, and divides the drift zone into at least one first anode-side drift zone layer and at least one second cathode-side drift zone layer. There is also disclosed a circuit configuration with such SiC—PN power diodes.

1. Field of the Invention
The invention relates to an integrated vertical silicon carbide PN power diode and a circuit arrangement with such power diodes.
Semiconductor components are at present made from a semiconductor material such as silicon or also from gallium arsenide (GaA) and gallium phosphate (Ga3P4), which, however, have a low thermal, chemical and physical stability.
Silicon carbide (SiC) on the other hand is a semiconductor material that has a physically highly stable crystal structure particularly due to its wurtzite- or zinc-blende crystal lattice. Depending on the polytype, SiC monocrystals have a large energy band gap of 2.2 eV to 3.3 eV, which makes them thermally, and especially mechanically, particularly stable and resistant to radiation damage. This makes SiC very attractive for such semiconductor components, which are exposed to extreme temperatures or extreme operating or environmental conditions, such as prevail, for example, in automotive and railway engineering. Semiconductor components based on SiC are able to operate over a large voltage and temperature range, for example up to 650° C. to 800° C., have very good switching properties and low losses and can also be operated at very high working frequencies. Compared to silicon, SiC has a stronger breakdown field (up to 10 times higher than for silicon) due to the better material properties, a higher heat conductivity (more than three times higher than with silicon) and a larger energy band gap (2.9 eV for 6 H—SiC).
SiC is particularly suitable for power components with a very high blocking voltage (600 V up to a few kV), such as high voltage (switching) diodes and field-effect transistors. Such SiC semiconductor components are, for example, used in converters for electrical drives, in switched-mode power supplies or in uninterruptible power supply systems. The purpose of the use of higher operating voltages is usually to be able to convert larger electrical outputs (of a magnitude of some kilowatts) with the same current.
Because the SiC semiconductor technology is still relatively young and in many respects not yet optimized, a series of problems exist in the production of SiC-based semiconductor components, which are yet to be solved to enable SiC components to become a reality in many component variants and in large unit quantities. The particular reason for this is that the same processes used for silicon components cannot simply be used for the production of SiC components. For example, doping by diffusion is all but unrealizable for SiC. Furthermore, the electrical activation of the doping atoms applied during the ion implantation is relatively difficult to control with SiC. For the aforementioned reasons, SiC is at present advantageously used for semiconductor components that can be produced by relatively simple technology such as Schottky diodes, PN diodes and field-effect transistors.
To explain the general problem, FIG. 1 of the drawing shows a schematic part section of the construction of an SiC power diode. The SiC power diode with the reference character 1 contains a very thick N-doped SiC semiconductor substrate, which is, for example, part of an SiC semiconductor wafer. The back of the semiconductor substrate 2 is connected to a cathode terminal K. An N-doped buffer layer 3, a low N-doped drift zone 4 and a highly P-doped emitter zone 5, which is connected on the front to an anode terminal A, are mounted in series on the front of the SiC semiconductor substrate 2. The thickness of the drift zone 4 and its doping concentration essentially determines the blocking state characteristics of the power diode 1.
FIG. 1a shows an idealized form of a current/voltage curve of the SiC power diode from FIG. 1 relative to temperature T, with, on the abscissa, the forward voltage UF being shown and, on the ordinate, the current I flowing at the same time being shown. KP is the intersection point of both diode characteristic curves at high currents or high forward voltages. The working point normally used for an SiC power diode is typically below the intersection point KP of the diode characteristic curves.
FIG. 1a shows that the forward voltage UF reduces with increasing temperature T at a given injected current I. At a given impressed forward voltage UF, the diode current I increases with increasing temperature T. This phenomenon is also known as negative temperature coefficients (du/dt<0) at constant current. The diodes normally used e.g. silicon diodes, on the other hand have a positive temperature coefficient with the forward voltage UF also increasing at a constant diode current I with increasing temperature T.
The phenomenon of the negative temperature coefficient is on the one hand due to the service life of a minority charge carrier increasing with increasing temperature. In addition or alternatively, this phenomenon is also due to the contact resistance between the anode metalling and the highly P-doped emitter zone reducing with increasing temperature.
This particular phenomenon with an SiC SC power diode as described in FIG. 1a, i.e. the presence of a negative temperature coefficient, is unwelcome or even damaging, particularly where several SiC power diodes are connected in parallel because, due to technology-imposed differences between different power diodes, a uniform distribution of the total current to the various power diodes of the parallel circuit cannot usually be guaranteed. As a result, one of the power diodes of the parallel circuit therefore typically takes a higher diode current than the other power diodes, which has the direct effect of causing this power diode to suffer a greater increase in temperature than the other power diodes. Because of the negative temperature coefficient, this in turn causes the current even through this power diode to additionally increase due to the characteristic curve, thus leading to a further increase in temperature of this power diode.
This latter phenomenon typically quickly leads to failure of this power diode and thus of the complete diode parallel circuit. This is a condition that should, of course, be avoided.

SiCED Electronics Development GmbH & Co. KG