A filtering method of flue gas of a boiler employing a filter apparatus integrated with ceramic filters and provided with a control mechanism for regenerating the ceramic filter by reverse cleaning and a detecting mechanism for detecting directly or indirectly unburnt component. Valves of a compressed gas are operated by a signal from the control mechanism when flying-over of the unburnt component is detected to thereby start at once frequent reverse cleaning wherein the compressed gas is blown into the cleaned gas spaces and thereafter the frequent reverse cleaning having a period shorter than four minutes continues until the flying-over of the unburnt component decreases to a small quantity.

1. Field of the Invention
This invention relates to a filtering method of flue gas emitted from a boiler such as a pressurized fluidized bed combustion boiler or a coal direct firing boiler, employing a filter apparatus integrated with plate-like filters or filter tubes made mainly of ceramics such as of mullite species, cordierite species, silicon carbide species or the like, and a filter apparatus for hot gas preferably employed in filtering flue gas of a boiler.
2. Discussion of the Related Art
A filter apparatus integrated with ceramic filters has already been reduced to practice for filtering flue gas at an elevated temperature of a low-level radioactive waste incinerator. However, the dust concentration of the flue gas is small and the variation of a combustion load thereof is extremely small. In other words, currently, it has been reduced to practice for an extremely limited usage.
On the other hand, the filter apparatus integrated with ceramic filters, is considered to be a component technology or a key technology for reducing to practice a coal gasifier power generating plant or a power generation plant employing a pressurized fluidized bed combustion boiler, which is a clean (wherein the emitted flue gas is composed of low NO.sub.x and SO.sub.x) energy technology of the next generation employing coal as fuel. Currently, intensive effort has been paid for the practical achievement of such a generation plant in various countries in the world.
In such a kind of power generation plant, power is generated by a combined cycle in two stages wherein power is generated by steam provided by a boiler and by driving a gas turbine by cleaned flue gas, which is obtained by removing dust from the flue gas after combustion under a pressurized state. Therefore, a power generating efficiency thereof is high. Since lime or dolomite is charged into the fluidized bed along with coal, almost no sulfur oxide (SO.sub.x) is generated. Since a combustion temperature thereof is restrained to be equal to or below approximately 900.degree. C., the generation of nitrogen oxide (NO.sub.x) is in a small quantity.
In employing the filter apparatus integrated with ceramic filters in filtering hot flue gas of a power generation plant or the like, it is necessary that the filter apparatus correspond to various operating conditions of the whole plant. Especially, in filtering flue gas emitted from a pressurized fluidized bed combustion boiler employing coal as fuel, when it is operated to increase the boiler load, combustion oxygen in the boiler becomes deficient and a large amount of unburnt component including soot is emitted.
In case of a bubbling bed type pressurized fluidized bed combustion boiler, when a load thereof varies under a low-load condition wherein a bed height of the fluidized bed is low, even if the oxygen concentration is high, a large amount of unburnt component is emitted in the flue gas, and carbon monoxide having a concentration exceeding 1000 ppm is often contained in the flue gas. Under such a situation, the concentration of dust in the flue gas increases 5 to 10 times as much as that in a steady state, by flying-over of the unburnt component, and a ratio of the unburnt component such as soot contained in the dust may be not smaller than 30%.
In the filtering of flue gas in the pressurized fluidized bed combustion boiler, it is the general tendency to adopt a system which prevents erosion of a gas turbine by dust, by cleaning flue gas which has been pre-cleaned by a cyclone at a prestage by a filter apparatus integrated with ceramic filters. However, in case of the cyclone, in a transient state wherein the dust concentration of the flue gas rapidly increases, the dust often overflow and an effective filtering function cannot be performed.
Moreover, the dust containing a large amount of unburnt component which pass through the cyclone, reaches ceramic filters of the filter apparatus. At this occasion, the dust concentration in the flue gas become 5 to 10 times as much as that in a steady state, and an increasing rate of a filtering pressure difference becomes 5 to 10 times as much as that in a steady state. In such a case, the operating conditions of the filter apparatus become unstable and finally the filtering function of the filter apparatus is lost.
Furthermore, there is a case wherein fuel is purged when the operation of the boiler is stopped, thereby blowing fuel which remains in a fuel charge manifold into the boiler. When this operation is performed just after a low-load operation, a large amount of coal powders are blown instantaneously through the pressurized fluidized bed combustion boiler, through the cyclone and reach the ceramic filters of the filter apparatus and the dust concentration in the flue gas reaches a value 100 to 300 times as much as that in the steady state.
In many tests in the filter apparatus wherein the filtering of flue gas in the pressurized fluidized bed combustion boiler is tested, the evaluation has been carried out under the condition wherein there is almost no variation of the boiler load. The reason is because the structure of the ceramic filters and the filter apparatus cannot stand the increase of filtering pressure difference by the dust laden gas having a high dust concentration containing unburnt component, generated by the variation of the boiler load, or a temperature variation caused by combustion of the unburnt component which takes place occasionally.
For instance, in a filter apparatus wherein ceramic filter tubes, each of which one end is closed, are arranged in a candle (candle stand) -like form (hereinafter candle type filter apparatus), disclosed in U.S. Pat. No. 4,904,287 and U.S. Pat. No. 5,059,227, since there is a problem in a supporting structure of a tube sheet made of a refractory alloy, when strong reverse cleaning is performed, the tube sheet and the filter tubes separately vibrate, the filter tubes or sealing parts thereof are damaged and the dusts leaks to the downstream side. Therefore, the reverse cleaning conditions are not determined by the necessary intensity of the reverse cleaning, but by the structural restrictions. Accordingly, when the filtering pressure difference becomes large, the reverse cleaning function becomes deficient, and as a result, the filtering becomes impossible due to the increase of the filtering pressure difference.
As another reason wherein a strong reverse cleaning of the filter cannot be adopted in the candle type filter apparatus, it is pointed out that the tube sheet is not cooled. Normally, the temperature of the flue gas emitted from the pressurized fluidized bed combustion boiler is in a range of 800.degree. to 950.degree. C. Therefore, creep of the tube sheet takes place when the filtering pressure difference becomes large even if the tube sheets made of a refractory alloy are employed.
Furthermore, since it is difficult to regulate flow in the space of the dust laden gas side, or the outside of the filter tubes into a smooth down-flow, there is a tendency wherein the dust adheres to and accumulates partially on the surface of the filter tubes in a large amount. When the adhered and accumulated unburnt component is ignited by any chance, it is combusted and serious damage is caused on the filter tubes.
Furthermore, in a filter apparatus provided with cross-flow filters having a structure of piled-up ceramic filter plates (hereinafter cross-flow type filter apparatus) described in Japanese Unexamined Patent Publication No. 198606/1990, when flue gas having a high dust concentration is to be filtered, gas passages are liable to be blocked by the dust. When strong reverse cleaning is necessary, the strength of the cross-flow filters is structurally insufficient. Accordingly, this device does not achieve a technical level wherein it can be operated under a variety of a boiler load.
In a filter apparatus having passages of dust laden gas penetrating inside of ceramic filter tubes (hereinafter tube type filter apparatus) disclosed in U.S. Pat. Nos. 4,584,003, 4,753,457, 4,867,769, 5,073,178 and the like, it is structurally possible to perform strong reverse cleaning. The filter apparatus is possible to be employed in a wide variety of operating conditions including those in a pressurized fluidized bed combustion boiler, by utilizing silicon carbide species or cordierite species ceramics for filter tubes.
In the tube type filter apparatus, since the inside of the filter tubes are passages for the dust laden gas, and the pressure difference of reverse cleaning gas is applied from outside of the filter tubes, mainly compressive stress is applied on the ceramics, and the pressure difference of the reverse cleaning does not help promote the damage of the filter tubes. Furthermore, the tube type filter apparatus is provided with the construction capable of achieving a large capacity by employing the filter tubes connected in the vertical direction and by piling up cleaned gas chambers. Since the dimensions of the tube sheets are comparatively small, the tube sheets can be cooled, if it is required. When the cooling is effective, the tube sheets do not creep even when strong reverse cleaning is performed. Therefore, it is possible to perform the strong reverse cleaning sufficiently. The apparatus can be employed under wide ranges of conditions of temperature, pressure and dust concentration.
That is to say, in the tube type filter apparatus, even when the dust concentration increases to some degree, it is possible to correspond thereto by previously designing the apparatus such that the strong reverse cleaning can be performed. Furthermore, in this filter apparatus, the flow of the dust laden gas is completely a down-flow and the flow area of the dust laden gas in the filter chamber is small, the dust is hard to be accumulated thickly on the filter, so long as an absolute quantity of the entrained unburnt component does not vary considerably. For instance, there causes no problem of thermal damage of the filter tubes or the like, so far as the unburnt component of approximately under 10% is always contained in the dust and the unburnt component combusts little by little.
However, even in the tube type filter apparatus, when a large amount of unburnt component flows into the apparatus in a short while, the dusts thickly adheres to and is accumulated on inner faces of lower end portions of the filter tubes wherein the down-flow velocities are almost null, the accumulated dust is ignited and combust in a short time, and temperatures at the portions of the filter tubes are elevated rapidly by the combustion heat. At this occasion, the temperature difference between the inside and the outside of the filter tubes exceeds an allowable temperature difference, and the filter tubes are destroyed by the thermal stress.
Furthermore, since the viscosity of gas is large at an elevated temperature, the dust in the hot gas floats against the gravity on the flow of the hot gas. Even when the main flow of the dust laden gas in a filter chamber (a space wherein solid-gas separation is performed in the filter apparatus) is constructed to be approximately a down-flow, a portion of fine dust floats against the gravity and is hard to drop down to the bottom of a hopper.
In an actual plant, flow of dust laden gas in the filter chamber constantly fluctuates by disorder of the dust laden gas flow caused by the operating conditions of the filter apparatus per se, or by disturbances at an upstream system or a downstream system of the plant, the turbulent flow of the dust laden gas accompanied by various secondary flows is constantly present in the filter chamber.
As a result, various phenomena causing the trouble mentioned below are generated in the filter chamber. One of the phenomena is bridging of dust, which is often observed in the candle type filter apparatus or the cross-flow type filter apparatus. By the presence of a transverse secondary flow or an upward secondary flow, even if the reverse cleaning of the ceramic filter is performed, the dust does not drop to the bottom of the hopper, and adhere again to the nearby ceramic filters. Finally, a portion of the flow passages on the side of the dust laden gas of the ceramic filters, is blocked by the accumulated dust, or a portion of the surface of the ceramic filters is covered with a thick accumulated layer of dust.
In case of the tube type filter apparatus, the gas flows at the lower end portions of the filter tubes fluctuate among the filter tubes, since the gas flow is influenced by a pressure and a velocity distribution of the dust laden gas at a gas inlet chamber of the vessel. It is clarified that there is even a filter tube wherein the dust laden gas flows reversely from the hopper.
When such phenomena take place and the dust is accumulated partially on the portions of the filter tubes, an effective filtration area of the ceramic filter decreases thereby decreasing the filtering capacity of the filter apparatus. In case of filtering the flue gas of the pressurized fluidized bed combustion boiler containing the unburnt component such as soot, the unburnt component contained in the accumulated dust is often ignited and combusted, and the ceramic filters receive a serious damage by the thermal stress caused by the combustion heat.
In filtering a synthetic gas in a coal gasifier plant, when the inner atmosphere is switched from a state, wherein the inside gas is filled with nonoxidizing gas, to air instantly after the stoppage of the operation, or oxidizing gas containing oxygen is introduced in the filter apparatus when the operation is restarted, the unburnt component in the accumulated dust is ignited and combusted whereby the ceramic filter receives a serious thermal stress damage.
A tube type filter apparatus is proposed in Japanese Examined Patent Publication No. 24251/1991, wherein the dust laden gas is extracted from the hopper (called blowing down) and is recirculated to the upstream of the filter apparatus. According to this filter apparatus, the dust laden gas at an elevated temperature having a high energy level is recirculated by the blowing down without depositing the dust laden gas to the outside, a downward flow is provided in the vicinity at the lower ends of the filter tubes, and the concentrated accumulation of dust at the lower end of the filter can be avoided. Therefore, the pressure difference of filtration can be decreased as a whole and the frequency of the reverse cleaning can be decreased.
However, a proper power is necessary to recirculate the dust laden gas. It is preferable to employ an ejector in use of steam or compressed air as a driving power, as a means of transporting the dust laden gas. However, the efficiency thereof is as small as approximately 4% at the most. This method can be employed in a case wherein a small quantity of the dust laden gas is recirculated. However, in recirculating a large amount of the dust laden gas, the energy loss is considerable.
Furthermore, recirculating the dust laden gas at an elevated temperature under pressure by a blower, is not a preferable method, since the installation of the blower is not easy and the blades of the blower are eroded by the dust. The recirculation of the dust laden gas is a potential method of solving the problem even in the case of the candle type filter apparatus. However, in this type of filter apparatus, since the flow area of the dust laden gas in the filter chamber is large, it is necessary to recirculate a large amount of the dust laden gas and the reduction of the method to practice is further difficult.
The blowing down operation wherein the dust laden gas is extracted from the hopper and is deposited, is experimentally performed with the effect being the same than with that in the blowing down operation wherein the recirculation is performed. However, the influence thereof on the efficiency of the plant is considerable and the extracted amount in a power generating plant is restricted to 1 to 2% of the total at the most. Therefore, a sufficient blowing down effect cannot be provided.

Filtering method of flue gas of a boiler and a filter apparatus for hot gas


A method for microfabrication of a three dimensional transistor stack having gate-all-around field-effect transistor devices. The channels hang between source/drain regions. Each channel is selectively deposited with layers of materials designed for adjusting the threshold voltage of the channel. The layers may be oxides, high-k materials, work function materials and metallization. The three dimensional transistor stack forms an array of high threshold voltage devices and low threshold voltage devices in a single package.

The manufacture of a semiconductor device (especially on the microscopic scale) requires various fabrication processes to be executed, such as film-forming depositions, etch mask creation, patterning, material etching and removal, and doping treatments. These processes are performed repeatedly to form desired semiconductor device elements on a substrate. Historically, with microfabrication, transistors have been created in one plane, with wiring/metallization formed above the active device plane, and have thus been characterized as two-dimensional (2D) circuits or 2D fabrication. Scaling efforts have greatly increased the number of transistors per unit area in 2D circuits, yet scaling efforts are running into greater challenges as scaling enters single digit nanometer semiconductor device fabrication nodes. Semiconductor device fabricators have expressed a desire for three-dimensional (3D) semiconductor circuits in which transistors are stacked on top of each other.
3D integration, that is, the vertical stacking of multiple devices, aims to overcome scaling limitations experienced in planar devices by increasing transistor density in volume rather than area. Although device stacking has been successfully demonstrated and implemented by the flash memory industry with the adoption of 3D NANO, application to random logic designs is substantially more difficult.
Threshold voltage (Vt) is the minimum voltage needed to activate a transistor within a CMOS (complementary metal-oxide-semiconductor) device. As CMOS devices have scaled down, there has been an increase in the number of different threshold voltages used within a given design. Using different threshold voltages enables designers to optimize specific portions of a chip to operate at higher performance or with lower power as needed. Conventional devices manufactured in conventional Foundry N5 technology nodes can incorporate as many as five different threshold voltages, which requires significant complexity within the chip manufacturing process.
Threshold voltage (Vt) can be "tuned" or created through several different approaches. One approach is to use channel doping to achieve different threshold voltages. As devices have scaled down in size and channel widths for leading-edge FINFET devices approach 50 Angstroms, and channel heights for nanowire/nanosheet devices likewise approach 50 Angstroms, channel doping is no longer a valid option for Vt tuning given the significantly reduced mobility with the doped channel coupled with the smaller dimensions. For such small channel dimensions, a single dopant atom can negatively impact the performance of the device. Further, the variability of the dopants within the channel is statistically very hard to control and these variations on atom-level scales may have significant impact on the threshold voltage of the device, thus the application of channel doping can generate multiple Vt tuning "flavors" or values which are not desired within a corresponding device.
Other approaches for Vt tuning of CMOS devices have been through work function metal (WFM) stack engineering, for example through the addition of multiple metal stack films surrounding the channel, or through increase of the work function metal stack thickness. Because the work function of the WFM stack is highly dependent upon the thickness variation within each film of the work function metal stack, complex integration processes have been developed using atomic layer deposition (ALO) of etch stop layers (ESL) and work function metal (WFM), multiple masking steps using expensive lithography operations, and wet etches in order to impart some controlled change in the work function metal stack to control threshold voltage. This approach has become the primary approach for threshold voltage tuning for state-of-the-art technology nodes but has come with increased integration and manufacturing complexity in the attempt to achieve the multiple threshold voltage requirements.
Accordingly, it is one object of the present disclosure to provide methods and systems in which threshold voltages (Vt) may be adjusted through selective deposition processes. Such processes can be adopted across FINFET, nanowire/nanosheet, complementary FET, and vertical FET devices.

Method for threshold voltage tuning through selective deposition of high-K metal gate (HKMG) film stacks


Provided are a method, electronic musical instrument, and computer storage device for mixing automatic accompaniment input and musical device input during a loop recording. During a first loop recording, automatic accompaniment information is generated from a storage device having patterns of automatic accompaniment information. First musical device input is received from at least one coupled musical device. The first musical device input and the automatic accompaniment input based on the generated automatic accompaniment information are mixed to produce a first mixed output. The first mixed output in a recording memory. During a second loop recording following the first loop recording, the first mixed output is outputted from the recording memory. Second musical device input from the at least one coupled musical device is received while outputting the first mixed output. The received second musical device input and the first mixed output are mixed to produce second mixed output. The second mixed output is stored in the recording memory.

1. Field of the Invention
The present invention relates to a method, electronic musical instrument, and computer storage device for mixing automatic accompaniment input and musical device input during a loop recording.
2. Description of the Related Art
Japanese Patent Application Nos. JP2006-023569 and JP2006-023594 describe recorders that are capable of mixing musical sounds stored in a memory device such as a Random Access Memory (RAM) with newly inputted musical sounds and multitrack-recording the mixed sounds in the memory device. By using such a recorder with a multitrack recording capability, loop phrases for automatic performance can be created by the so-called "loop recording" in which a loop segment with a predetermined length is looped (repeated), and performance sounds inputted in the respective loops are recorded in multitracks.

Mixing automatic accompaniment input and musical device input during a loop recording


There are provided methods and apparatus for measuring a received quality of at least one of a video multicast and a video broadcast for a plurality of users. A method includes receiving data from the plurality of users regarding the received quality, and increasing a weight of the data for any of the plurality of users having the received quality greater than a threshold.

In a video broadcast and/or multicast (hereinafter also referred to collectively as "broadcast/multicast") application, irrespective of whether over a wireless or a wired network, the recipients of the same video may experience different channel conditions at the same time. Furthermore, the same recipient(s) may also experience different channel conditions at different times. Consequently, the decoded video qualities (either perceptual or in terms of an objective quality measure) for different recipients, or the same recipient at different times, varies.
In accordance with some prior art broadcast/multicast systems, such systems are designed to satisfy a target quality for the user with the worst channel condition (i.e., the highest loss rate). Using this typical approach, users with good channels are unnecessarily penalized.
In one prior art approach, it has been proposed to minimize the maximum performance degradation due to multicast among multiple users. An example of this prior art approach will now be provided, where a single user i with a loss rate pi is considered. Given the total rate constraint Rt, the optimal source coding and channel coding parameters Ai are chosen to minimize the expected end-to-end distortion for this user, with a corresponding minimal distortion Dopti, as follows:
                                          A            i                    =                                                    arg                                                                                min                                            A                :                                                                            R                      e                                        /                    r                                    <=                  R                                                                                D                                            (                                                      p                    i                                    ,                  A                                )                                                    ,                                                                D            opt            i                    =                      D                                      (                                                p                  i                                ,                                  A                  i                                            )                                                          (        1        )
In the multicast/broadcast case, for a particular source/channel coding scheme characterized by parameter set AM, the end-to-end distortion for user i is DMi(pi,AM). In the prior art approach, it has been proposed to choose AM to minimize the maximum performance degradation among all users. Specifically,
                              A          M                =                              arg                          A              :                                                                    R                    e                                    /                  r                                <=                                  R                  t                                                                        min                                {                                          max                i                                                          [                                                                            D                      M                      i                                                                                (                                                                        p                          i                                                ,                        A                                            )                                                        -                                      D                    opt                    i                                                  ]                                      }                                              (        2        )
In this way, the receiving quality of each user can be degraded from its optimal performance by a certain amount. However, none of the users are overly penalized.
A problem with the above measure is that it is quite complex to compute. System optimization based on this metric requires intense computation. Moreover, it is also not clear whether equalizing performance degradation due to multicast is an appropriate design criterion.

Method and apparatus for evaluating performance for a video broadcast and/or multicast


The wall of a pressure vessel tube having stress-corrosion cracks or the like is repaired by localized melting using laser welding, for fusing over defects by melting and re-solidifying the metal. A high powered laser beam is focused at a limited area or spot on the internal wall of the tube. The welding head is operated at sufficient power and is relatively moved in the tube at a sufficient rate to melt the spot while advancing along a line on the internal surface of the wall. The wall is melted to a depth of part or all of the thickness of the wall. Points at which the tube has been melted by the focused beam cool following passage of the welding head. The welding head is also advanced laterally of the line, either continuously or stepwise. Localized melting and cooling of the tube material continues progressively, line by overlapping and/or adjacent line, to melt and reform the degraded area. By successively melting, and optionally alloying linear sections of the wall using an alloying material, stress-corrosion cracks and similar defects are fused over, repairing the degraded area. The localization of the melting is such that the metal does not substantially flow and the metal cools quickly following passage of the weld head, to below a temperature of sensitization.

1. Field of the Invention
The invention relates to reforming degraded areas in ductile materials, in particular by melting a localized area to a predetermined depth, re-forming the localized area by cooling it, and advancing the localized melting and cooling through the degraded area to restore it to an integrally continuous form. The melting preferably involves scanning over a surface along successive adjacent lines on the inside surface of a tube, to progressively melt and fuse over defects at least to a depth sufficient to restore the tube to a serviceable condition for effecting heat exchange, pressure confinement or the like. The invention is particularly applicable to fusing service-induced stress and corrosion defects in coolant circuit tubes of pressurized water nuclear reactors. Localized melting is preferably accomplished by welding, especially with a laser weld head. An alloying material can be included during welding, the alloying material being supplied as a powder, gas or self-supporting tube and consumed in the process.
2. Prior Art
Heat transfer tubes in the steam generator systems of nuclear power plants are subject to degradation over time of the primary pressure barrier in zones of high mechanical stress. The pressure and temperature of coolant in the coolant circuit can be substantial. Static pressure due to the coolant may be on the order of 100 bar (2,200 psi) in the coolant circuit and the coolant temperature can be 600.degree. F. when the plant is operational. The thermal and mechanical stresses applied to the tubes tend to degrade the tubes in the regions of highest stress.
One area of concern is the tubing in heat transfer devices. In a reactor system, heated water from a primary coolant circuit is passed through heat exchanger tubes having a second flow of water passing outside the tubes. Should the barrier defined by a tube deteriorate, the secondary coolant may become contaminated with radiation from the primary coolant. It is expensive to replace the heat exchangers, and methods have evolved for repairing degraded steam generator heat exchanger tubes in various situations. However, the inaccessibility of the heat exchanger tubes as well as the radioactive environment surrounding the heat exchanger tubes present difficult problems.
A steam generator heat exchanger generally has a number of substantially parallel-flow tubes coupled between inlet and outlet manifolds. Whereas there are parallel alternative flow paths, one method of dealing with a deteriorated steam generator tube is to simply plug lit to prevent leakage. Plugs are inserted upstream and downstream of the plugged zone, isolating the zone of deterioration from the primary side coolant, and thus preventing leakage.
Plugging an affected tube reduces the active heat exchange surface area and results in a reduction in steam generator performance. Designers build an extra margin into the design of heat exchangers of this type, in recognition that it may become necessary in the future to plug some of the heat exchanger tubes without replacing the entire unit. If carried to an extreme in which the number of plugs installed exceeds the plugging margin provided according to the steam generator design, the steam generator must be de-rated because the rated heat generation capacity exceeds the available heat transfer capacity of the heat exchanger.
An alternative repair known as sleeving involves isolating only the surface of the tube in the area of deterioration while allowing primary coolant to flow in the tube, i.e., without removing the entire tube from service. Sleeving involves fitting an undersized length of tubing (the sleeve) into the affected tube, and attaching the sleeve upstream and downstream of the degraded zone to the inner walls of the tube, preferably sealing the sleeve to the tube to prevent leakage between them. The sleeve forms a seal and restores the integrity of the pressure boundary. The sleeve may be attached to the walls of the tube by mechanical means, such as by forming complementary bulges in the sleeve and the tube after positioning the sleeve to lap the area to be repaired. For a hermetic leak-tight seal the sleeve can be welded to the tubing, for example using gas tungsten arc or laser welding. Alternatively, the sleeve and tube can be attached by brazing. In either case, the sleeve is joined to the tube along the ends of the sleeve, typically along a circular line at each end of the sleeve.
The sleeve does not completely occlude the tube like a plug, but there are penalties. Thermal transfer declines due to flow reduction resulting from the reduced internal diameter of the tube and the discontinuity defined by the sleeve. In an extensive sleeving program, or in a generator that already has a large number of plucks, sleeving may not be practical. The thermal transfer characteristics of the heat exchanger tube are adversely affected by a sleeve. The sleeve thickens the overall tube wail. Any area of relatively lower thermally conductive contact between the sleeve and the original tube, such as a gap or corroded zone, forms an insulating zone, reducing the heat transfer efficiency of the system. The effect of a single sleeve may not be large, but large scale sleeving, especially in the support plate regions, can significantly reduce the efficiency of the steam generator.
The attachment zone of the sleeve, depending on the specific method of attachment to the tube, produces a local stress concentration in the original parent tube. The zones of attachment are at increased risk of further primary water attack with continued operation of the generator, requiring additional treatments or operations to reduce susceptibility to degradation at the attachment zones. Sleeves thus introduce additional process steps, down-time, and costs for materials and equipment.
Sleeving for a steam generator plant of this type must be made to specific requirements of the ASME Code. Because applications vary, the length and configuration of the sleeves needed varies as well, making it necessary to stock a large variety of sleeves to enable repairs at different areas.
Laser welding is one means to attach a supplemental sleeve inside a tube. U.S. Pat. No. 4,694,136--Kasner et al discloses welding the ends of a sleeve to the inner walls of a heat exchanger tube in this manner. After placing the sleeve inside the tube and mechanically forming complementary annular bulges in the sleeve and the tube to fix them against displacement, a 500 to 700 watt laser beam is applied to the inner surface of the sleeve, either in successive closely spaced lines or in a helical continuous line. The area melted by the laser is about 0.24 inches in width (0.61 cm) and extends completely through the material of the sleeve, and about 0.025 inches (0.064 cm) deep into the tube, or about halfway through the tube wall. The melted material of the sleeve and tube are mingled and fused around the circumference at the point of attachment, forming a hermetic connection of the sleeve and the tube.
According to Japanese Patent Publication 2-199,397, dated Aug. 7, 1990, it is known to heat-treat degraded areas of a tube along the inner surface as a means to reduce the later occurrence of cracking caused by tensile stress and corrosion. The incidence of stress-corrosion cracking in austenitic stainless steel is particularly increased if the steel has been heated to a temperature between 550.degree. and 800.degree. C. (about 1,000.degree. to 1,500.degree. F.). The phenomenon of increased cracking within this temperature range, known as sensitization, occurs due to precipitation of carbides from solution with the iron, especially along interstices between fine granular bodies. Typically, in the production of steel, care is taken to cool the steel quickly through the sensitization temperature range, to minimize the degradation of structural integrity caused by sensitization. According to said Japanese Patent Publication 2-199,397, heat treating is accomplished using a YAG laser beam to produce a temperature rise on the inner surface that is limited to below the temperature of sensitization. The laser beam is focused at a localized internal surface of the pipe and moved over a predetermined axial length at a sufficient rate to limit the temperature rise. A chromium or titanium powder can be applied to the internal surface prior to heat treating, for improving the stress-corrosion characteristics of the tube as a part of the heat treating process. The heat treatment is described as thereby assisting in either preventing stress-corrosion cracks or repairing stress-corrosion cracks after they have occurred.
Plugging and sleeving deal with problems in the structure of a tube by isolating the degraded portion of the tube from the primary coolant. Heat treating prior to the occurrence of cracks may be helpful, but heat treating after cracks have occurred requires the application of additional material, and therefore resembles sleeving. It would be desirable to reconstitute the tube rather than to patch over or isolate it to deal with a deteriorated zone. Reconstituting the tube in situ by actually melting and then solidifying the tube material would preclude the need for add-on structures adversely affecting the flow characteristics of the tube or the plant. An additional material can be employed for alloying with the material of the original tube, or the tube can simply be reformed from its original metal.
Whereas melting a metal allows the metal to flow, it would appear to be impossible to reform a tube in this manner without providing some form of mold for support. However, by melting only a small localized area at any one time, e.g., by laser welding, proceeding along the length of the tube to be repaired in a generally helical or axial scanning pattern, and/or along parallel lines or the like, it is possible according to the invention to reform the tube incrementally and to fuse over stress-corrosion cracks. Moreover, by melting a small area at a time using a focused laser, the melted metal is retained in place by the surrounding solid metal. As the point of welding passes, the thermal sink provided by the surrounding metal quickly cools the solidified metal through the sensitization range.
It is an object of the invention to repair a tube having a deteriorated area, especially a heat exchanger tube in the heat exchanger of a nuclear steam generator plant, by melting a depth of the inner surface of the tube using welding technology, thereby fusing over cracks and rendering the tube material once again continuous over the zone of deterioration, and to a sufficient depth to return the tube to serviceable condition.
It is a further object of the invention to repair a pressure vessel tube without substantially decreasing the internal diameter of the tube or increasing the external diameter, by melting and reforming the tube material at a localized small area, and scanning the area of localized melting to proceed over the tube surface in adjacent or overlapping lines.
It is another object of the invention to provide a means to repair a tube conveniently, which improves over results obtainable either by plugging the tube, by adding a supplementary support/sealing sleeve, or by heat treating the tube in the presence of a supplemental material. In particular it is an object to melt and reform the tube in incremental lines so that cracks are fused over and the heat exchange capacity of the repaired tube is at least as good as that of the original tube.
It is also an object of the invention to employ a tracking optical welding technique using a high powered laser, for surface welding at least a depth at the inside of a tube along a progressive overlapping spiral path, at a sufficiently slow rate of advance and a sufficiently high power level, to melt the tube at an isolated area that quickly cools after the welding point passes.
It is another object of the invention to improve the surface of a pressure vessel tube by surface welding, optionally in the presence of an alloying material which modifies the characteristics of the original tube in the area of the repair. The alloying material can be a welding powder, gas or consumable sleeve disposed in the degraded area prior to or concurrently with welding.
These and other aspects of the invention are met in a method for repairing a wall of a pressure vessel tube having a degraded area by melting a localized area to a predetermined depth, re-forming the localized area by cooling it, and advancing the localized melting and cooling through the degraded area to restore it to an integrally continuous form. The repair is effected by positioning in the tube a high powered laser welding head with the beam energy focused at a limited area or spot on the internal wall of the tube. The welding head is relatively moved in the tube at a sufficient rate to weld along a line on the internal wall for melting the tube in the degraded area at least to a depth equal to a part of the thickness of the tube wall. The depth of melting is sufficient to restore the tube to serviceable condition by reforming a functionally sufficient thickness of tube, with regard to the particular purpose of the tube. The point at which the tube has been melted by the focused energy cools following passage of the welding head. As the point of application of the welding head advances along a line, the line is likewise advanced laterally. Localized melting and cooling of the tube material continues, line by adjacent or overlapping line, to encompass the degraded area. By successively melting, and optionally applying one or more alloying materials such as a powder, aerosol or insert, using materials known in the art, linear sections of the wall, stress-corrosion cracks and similar defects are fused over, repairing the degraded area. The optional additional welding material can be employed for improving the characteristics of the tube as compared to the original tube. Preferably, the lateral advance is less than the width of localized melting, causing the lines to overlap and continuously re-form the degraded surface. Although the entire surface of the tube can be melted and reformed in this manner, the localization of the melting at any one time is such that the metal does not substantially flow and the metal cools quickly following passage of the weld head, to below the temperature of sensitization. The advance of the welding line and the lateral displacement can be stepwise or continuous, and can be oriented axially or radially.
The realization of these objects will be appreciated from the following discussion of particular exemplary embodiments of the invention. However it should also be appreciated that the invention is capable of variation from the examples, in accordance with the scope of the invention as claimed.


A method and system for power management among batteries of varying states of health. Two or more battery packs are switched on and off in square wave pulses to energize a multi-winding transformer, and the output of the transformer is used to power a load. As the state of charge of the battery packs decrease at different rates, the duty cycle of each battery pack's switch pulse is made proportional to its state of charge relative to the other battery packs. The battery pack with the greatest state of charge has the longest on-time and provides the most energy to the transformer, yet all battery packs contribute. A baseline duty cycle is computed by a proportional integral control module, based on voltage measurements at the load. Energy contribution is managed so that state of charge does not diverge even when the battery packs have widely varying states of health.

1. Field of the Invention
This invention relates generally to state of charge (SOC) balancing among battery packs and, more particularly, to a method and system for power management among battery packs with varying states of health which uses a switched transformer to provide proportional active SOC balancing.
2. Discussion of the Related Art
Electric vehicles and engine/electric hybrid vehicles are rapidly gaining popularity in today's automotive marketplace. Electric and hybrid vehicles offer several desirable features, such as reduced emissions, reduced usage of petroleum-based fuels, and potentially lower operating costs. A key component of both electric and hybrid vehicles is the battery pack. Battery packs in these vehicles typically consist of numerous interconnected cells, which can deliver a lot of power on demand to drive the vehicle.
After a few years of service in an electric or hybrid vehicle, battery packs often need to be replaced due to degradation and variation in the state of health of the individual cells, which leads to reduced driving range for the vehicle. Yet, even with a somewhat reduced state of health, an electric vehicle battery pack can still store a considerable amount of energy, and can be used for other applications besides powering a vehicle. A variety of different post-vehicle-life uses for such battery packs have been proposed, including using the battery packs in Community Energy Storage (CES) systems.
CES systems store energy for a small community, such as a residential subdivision or a commercial or industrial complex. CES systems typically serve to augment power available from the utility grid, and are useful in their ability to store locally-generated energy from sources such as solar and wind. Post-vehicle-life battery packs from electric vehicles can be used in CES systems, but their efficiency may be diminished by variations in the state of health of individual cells or sections of the battery packs. A method of managing variations in battery state of health is needed which does not simply bleed off power from higher state of charge batteries, and which enables use of maximum available energy in the battery packs.

Scalable method of proportional active state of charge balancing for managing variations in the state of health of batteries


Embodiments of the present disclosure provide a method, device and computer readable storage medium implemented at a relay device. According to embodiments of the present disclosure, the relay device determines whether a terminal device served by a network slice has to be handed over. In a case of determining that the terminal device has to be handed over, the relay device sends a request for local information to at least one candidate relay device, and the local information includes at least one of information associated with a backhaul link from a candidate relay device to a network device and slice configuration information of the candidate relay device. Based on the received local information, the relay device determines a candidate relay device for handover of the terminal device. According to embodiments of the present disclosure, the relay device determines the candidate relay device to which the terminal device has to be handed over, based at least on the information associated with a backhaul link and the information associated with a network slice, so as to satisfy network slice configuration requirement and ensure backhaul quality of the terminal device.

In order to deal with an intensive cell configuration in the fifth generation (5G) of the communication system according to 3GPP and to reduce deployment of backhaul optical fibers, integrated access and backhaul (IAB) of a communication system has been developed into a research topic of 5G. For example, in 5G IAB, a relay node may be deployed in a communication network to simply backhaul complexity of the communication network and increase spectral efficiency and system capacity of a hotspot area. In a communication system comprising a relay node, a terminal device accesses a relay device using an access link from the terminal device to the relay device, so as to enable wireless or wired bidirectional communication with the relay device. The relay device accesses the network device using a backhaul link from the relay device to the network device, for example, a base station, so as to enable wireless or wired bidirectional communication with the network device.
In order to enhance flexibility and extensibility of the communication network, there is provided a network slicing technology to tailor a plurality of logical networks for different users or applications based on the existing communication architecture. Specifically, the network slicing technology allows the communication network to be divided into a plurality of logically or physically different network slices. Each of the network slices may optimize a network for one or more communication traffics having a particular quality of service (QoS) requirement, so as to flexibly support various types of communication traffics for different levels of users. In the communication network including the relay device and the network device, how to take related configuration of a network slice into account in mobility management such as handover is a problem to be solved.

Communication method, device and computer readable storage medium for relay device


A second gear rotating at a rotation speed faster than a rotation speed of a first gear while meshing therewith, a magnet provided on the second gear and rotating together therewith, and a small angle detection magnetic sensor disposed in a vicinity of where the second gear is fixed and configured to detect a magnetic line of force of the magnet are provided. Meanwhile, a third gear rotating at a rotation speed slower than the rotation speed of the second gear in synchronization with the first gear, a magnet provided on the third gear and rotating together therewith, and a large angle detection magnetic sensor disposed in a vicinity of where the third gear is fixed and configured to detect a magnetic line of force of the magnet are provided. A rotation angle of a steering shaft is calculated based on angle data detected in the small angle detection magnetic sensor and the large angle detection magnetic sensor.

1. Field of the Invention
The present invention relates to a steering angle sensor detecting a rotation angle of a steering mounted on a vehicle, and particularly, to a technology for improving accuracy of the detection.
2. Description of the Related Art
As a conventional example of a steering angle sensor mounted on a vehicle, there is one using a system, in which a large diameter gear is disposed coaxially to a steering, and further, a small diameter gear meshing with this large diameter gear is disposed, and a rotation angle of this small diameter gear is detected.
As shown in FIG. 1, accompanied with the steering shaft 101 rotates, the large diameter gear 102 rotates, and the small diameter gear 103 meshing therewith is rotationally driven. In addition, the magnet 104 is disposed on the center of the small diameter gear 103, and further, the hall IC 105 is disposed in the vicinity of where the magnet 104 is disposed. Hence, the direction of the magnet 104 can be detected by the hall IC 105, and eventually, the rotation angle of the small diameter gear 103 can be detected.
Accordingly, the rotation angle of the steering shaft 101 can be calculated based on output signals of the hall IC 105.
However, in the steering angle sensor thus configured, the number of teeth of the small diameter gear 102 is smaller than that of the large diameter gear 102, in which, for example, a ratio of the numbers is 1:4. Moreover, in the steering shaft 101, the total steering angle is approximately less than 4 turns, and therefore, the small diameter gear 103 will make a total of approximately 15 turns.
Hence, though the hall IC 105 can detect the rotation angle of the small diameter gear 103, the hall IC 105 cannot recognize the absolute position of the steering shaft 101, that is, cannot recognize how many turns the small diameter gear 103 has made among the total of 15 turns. Therefore, the conventional steering angle sensor has had a drawback that the sensor must detect the steering angle with reference to a steering angle of the steering shaft 101 of 0 degree, that is, with reference to a straight ahead position of the vehicle, which makes it impossible to detect the steering angle until a reference position signal to notify that the vehicle is at the straight ahead position is given from the vehicle.
Meanwhile, in order to solve this problem, there has been proposed a method of constantly monitoring variations of the steering angle by energizing the steering angle sensor even when the ignition switch of the vehicle is turned off. However, this method has caused a problem that a heavy load is put on a battery because electric power is consumed even when the ignition switch is turned off.
As described above, the conventional steering angle sensor has had the problem that the sensor cannot detect the steering angle until the straight ahead position of the vehicle is detected. Furthermore, the method in which the steering angle sensor is energized even when the ignition switch is turned off has had a drawback that the method was impractical because more electric power is consumed.
The present invention has been created in order to solve the conventional problem as described above. It is an object of the present invention to provide a steering angle sensor capable of detecting a steering angle of a vehicle by a simple method.
In order to achieve the foregoing object, the present invention provides a steering angle sensor, including a first gear rotating in synchronization with a steering shaft, a second gear rotating in synchronization with the first gear at a rotation speed faster than a rotation speed of the first gear, a small angle detection magnet provided on the second gear and rotating together with the second gear, a small angle detection magnetic sensor disposed in a vicinity of where the second gear is fixed and configured to detect a magnetic line of force of the small angle detection magnet, a third gear rotating at a rotation speed slower than the rotation speed of the second gear in synchronization with the first gear, a large angle detection magnet provided on the third gear and rotating together with the third gear, and a large angle detection magnetic sensor disposed in a vicinity of where the third gear is fixed and configured to detect a magnetic line of force of the large angle detection magnet, wherein a rotation angle of the steering shaft is calculated based on angle data detected in the small angle detection magnetic sensor and the large angle detection magnetic sensor.
The steering angle sensor may be configured such that the small angle detection magnetic sensor supplies a periodic signal of a triangular wave accompanied by a rotational movement of the second gear, and that the large angle detection magnetic sensor supplies a periodic signal of a triangular wave accompanied by a rotational movement of the third gear, in which the periodic signal has a longer period than a period of the periodic signal supplied by the small angle detection magnetic sensor.
The steering angle sensor may be configured such that detection data by the small angle detection magnetic sensor and detection data by the large angle detection magnetic sensor are set different from each other in accordance with an absolute angular position of the steering shaft.
The steering angle sensor may be configured such that a signal, in which a gradient of a detection value detected by the large angle detection magnetic sensor is made to coincide with a gradient of a detection value detected by the small angle detection magnetic sensor, is created as a conversion signal, and that a difference between the conversion signal and a detection result by the small angle detection magnetic sensor is calculated, and it is determined as to which period in a periodic waveform supplied from the large angle detection magnetic sensor an absolute steering angle of the steering shaft belongs in accordance with the remainder when a value of the difference is divided by a predetermined number of steps.


This invention provides a data distribution system capable of changing dynamically a capability of the data distribution system. In the present invention, there are provided a plurality of distributing servers, a supplying server connected to each of the plurality of distributing servers. In the case that there is a request for a content not included in the disk unit of the distributing server, it is transmitted from the supplying server to the distributing server and concurrently the content is distributed from the distributing server to the requesting set top box.

The present invention relates to a data distribution system, and more particularly to a data distribution system having distribution servers.
A data distribution system distributes data (i.e., video data) to clients (i.e., set top boxes). The data distribution system has distributing servers which distribute data ("content") to the clients by a stream.
In the data distribution system, work load of the distributing servers is not always balanced. If some specific distributing severs are accessed more than other distributing servers, the entire performance of the system is degraded.
On the other hand, if all of the distributing servers store same contents in duplicate, too much capacity is required in the distributing servers.

Data distribution system that performs load balancing by directly transmitting data between distribution servers


A SOI-MEMS gyroscope has a three fold symmetrical construction such that is symmetrical in the x direction, the y direction and diagonally. The gyroscope is suspended above a silicon substrate by lateral flexures that are located at the corners of the proof mass and by central flexures that are positioned at the center regions of the proof mass. The proof mass, lateral flexures, and central flexures are formed of a silicon composition with the flexures supporting the proof mass such that the proof mass will not touch the underlying base silicon substrate even when subjected to extreme G forces. Comb finger actuators apply an electrostatic force to the proof mass in the x direction; and, when experiencing an external rotational rate around the z-axis, the Coriolis force acts along the y direction and the resulting deflection is sensed by a pair of comb-finger capacitors connected as a differential capacitive voltage divider.

I. Field of the invention
The present invention relates to gyroscopes.
More particularly, the present invention incorporates a stationary three-fold symmetric vibratory rate gyroscope implementation provided on a thick-film silicon-on-insulator (SOI), micro electro-mechanical system (MEMS).
II. Discussion of the Background
Small, affordable, and reliable inertial components are required for small diameter precision-guided military weapon systems. Gyroscopes are inertial components or devices that can sense angular rotation and/or rotation rate. The ring laser and interferometric fiber optic gyroscopes dominate the current tactical missile system market. Although these gyroscope technologies meet most inertial requirements, they tend to be moderately expensive. Recent advancements in microelectromechanical systems (MEMS) technologies make it possible to develop miniaturized, low cost angular rate sensors. The process technologies initially developed for fabricating integrated circuits have now evolved to allow development of MEMS devices.
Although many organizations are developing MEMS gyroscopes for a variety of applications, most do not begin to address the demanding and challenging requirements for military combat systems. Requirements for small precision guided weapons were the basis for the MEMS gyroscope development criteria. Rate sensing in many small diameter missile guidance units typically requires a rate resolution of 10°/hr. Additionally, for a particular guided munition, a large roll rate about its longitudinal axis may be experienced during flight. The anticipated rotational rates encompass a range of −3000° to +3000°/sec, resulting in a dynamic range of 107.
In order to control the heading of this system during flight, the system must know its roll angle about the longitudinal axis so that the control systems can adjust accordingly. Therefore, the accuracy of this angular measurement must correspond to a bias stability of 10°/hr in order for the guidance system to compensate.
Furthermore, actuators in the control system of the guided munition may result in a substantial vibration environment. Large shocks of greater than 1000 G's can be seen at frequencies ranging from 5 kHz to 15 kHz. Additionally, the inertial device must operate through military temperature environments (−55° to +125°). The criteria for achieving superior resolution while measuring large rotation rate adds difficulty to design determination since there are tradeoffs that exist in determining the mechanical structure's topology.
For example, achieving superior resolution requires substantial inertial mass available in the device. However, when a large mass design is devised, the resulting deflections due to large values of rotational rate are generally more than the device can accommodate. In most cases, enough electrostatic feedback force cannot be produced to counter the Coriolis forces. Given that the MEMS gyroscope must not only survive but operate through these harsh environments, the challenge has been to develop a robust, accurate and reliable MEMS gyroscope.
MEMS angular rate sensors or gyroscopes that detect angular rate utilize the Coriolis Effect. A vibratory rate gyroscope is a sensor that detects and measures rotation by generating and measuring Coriolis acceleration. In other words, the sensing method used in a vibratory rate gyroscope is based on the Coriolis pseudo-force resulting from a translating body in a rotating frame of reference. The conventional illustrations of FIG. 1 and FIG. 2 demonstrate the Coriolis Effect on an object.
A mass, m, is moving at time, t, with a velocity vx along both the (x,y) and (x′,y′) axes.
At time t+dt, the (x′,y′) axes have rotated Ωdt where Ω is the rotational rate. In accordance with Newton's Laws, the mass is still moving with velocity vx in the (x,y) frame of reference.
However, in the (x′,y′) frame of reference, is appears that the velocity, vx has moved by an amount dvx. Therefore the Coriolis acceleration and force is:
                    α        =                                            ⅆ              v                                      ⅆ              t                                =                                    -              2                                                                                Ω                                                                                v              x                                                          Equation                                                            (          1          )                    F=ma=−2mΩvx   Equation (2)
The fundamental result from this simple derivation of system dynamics is that a translating mass in a rotational frame of reference will appear to experience, within the rotating frame, a force orthogonal to its velocity and proportional to its velocity and the rate of rotation of that frame of reference.
The conventional vibratory rate gyroscope consists of a mass-spring system that has at least two orthogonal modes of oscillation (FIG. 3). The mass is forced to have an oscillatory velocity in the frame of reference of the device along the x-axis. Anchored springs 16 and 14 having respective identical spring constants kx and ky are attached to respective rollers 20 and 18 so as to provide a suspension that constrains the mass to particular orthogonal oscillation modes. When the device experiences rotation, the Coriolis force induces oscillation of the orthogonal mode of the device. Sensors detect this motion and provide a signal from which the rotational rate is extracted. The Coriolis force is proportional to the external rotation rate.
The equations of motion for a mass-spring system moving in a non-inertial reference frame are found using Lagrangian dynamics. Expressions for the potential energy and kinetic energy of the system must be derived first.
The global frame of reference is the p-q-a frame, the local frame of reference x-y-φ is rotated by an angle θ with respect to the global frame. The local frame is also translated by rx and ry with respect to the global frame.
The potential energy stored in the springs is:
                    PE        =                                            1              2                                                  k              x                                                  x              2                                +                                    1              2                                                  k              y                                                  y              2                                +                                    1              2                                                  k                              ϕ                                                                                ϕ              2                                                          Equation                                                            (          3          )
The kinetic energy is calculated in the global frame of reference, using the global variables:
                    KE        =                                            1              2                                                                  m                                                  (                                                            ⅆ                      q                                                              ⅆ                      t                                                        )                                            2                                =                                                    1                2                                                                            m                                                        (                                                                  ⅆ                        p                                                                    ⅆ                        t                                                              )                                                  2                                      +                                          1                2                                                                            I                                                        (                                                                  ⅆ                        α                                                                    ⅆ                        t                                                              )                                                  2                                                                        Equation                                                            (          4          )
The global variables are related to variables in the local frame of reference by rotation matrices:q(t)=cos(θ)x(t)−sin(θ)y(t)+rx(t)   Equation (5)p(t)=sin(θ)x(t)+cos(θ)y(t)+ry(t)   Equation (6)i a(t)=θ(t)+φ(t)   Equation (7)
The equations of motion in the local frame of reference are found from
                              F                      x            i                          =                                            ∂              L                                      ∂                              x                i                                              -                                    ⅆ                              ∂                L                                                                    ⅆ                t                                                          ∂                                  x                  i                                                                                Equation                                                            (          8          )
Where xi are generalized coordinates, Fx, are external forces such as damping and excitation forces, and L is the Lagrangian (L=KE−PE).
The global coordinates in the kinetic energy relation are substituted by Equations (5), (6) and (7) to convert to local coordinates. Equation (8) is then applied for each of the on-chip coordinates (x, y, φ), by replacing the generalized coordinate by the respective on-chip coordinate, yielding:
                                             x            ¨                    =                                                    -                                  ω                  x                  2                                                          x                        -                                                            ω                  x                                Q                                                          x                .                                      -                                          F                x                            m                        +                          x                                                                                Ω                2                                      +                          y                                                                                Ω                .                                      +                          2                                                                                Ω                                                                                y                .                                      -                                          a                x                                          cos                                                                                θ                        -                                          a                y                                          sin                                                                                θ                                                            Equation                                                                          (            9            )                                                                    y            ¨                    =                                                    -                                  ω                  y                  2                                                          y                        -                                                            ω                  y                                Q                                                          y                .                                      -                          2                                                                                Ω                                                                                x                .                                      +                          y                                                                                Ω                2                                      -                          x                                                                                Ω                .                                      +                                          a                x                                          sin                                                                                θ                        -                                          a                y                                          cos                                                                                θ                                                            Equation                                                                          (            10            )                                                                    I                                                                                ϕ              ¨                                =                                                    -                                  k                  ϕ                                                                          ϕ                .                                      -                          I                                                                                ϕ                                                            Equation                                                                          (            11            )
Where wx2=kx/m and wy2=ky/m are the resonant frequencies of the x and y modes, respectively, ax and ay are external accelerations, and Q is the quality factor of resonance. The Coriolis accelerations are the 2Ω{dot over (y)} and 2Ω{dot over (x)} terms. The last two terms in Equations (9) and (10) are the acceleration terms, which create transients at the natural frequency of the system. The terms yΩ and xΩ refer to the inertia of angular acceleration. The terms yΩ2 and xΩ2 are centripetal accelerations, and act as spring softeners.
The importance of the above derivation is that it includes extra terms in the equations of motion beyond the standard Coriolis force terms. When experiencing large rotational rates and angular accelerations, these extra terms, the centripetal acceleration, linear acceleration and angular accelerations, play larger roles in the error terms of the rotational rate signal.
In addition, the derivation shows, as is commonly known, the role of matching resonant frequencies so that the benefits of a high quality factor can be applied to the sensor.
The coefficients in the above equations, particularly the spring constant and quality factor, are dependent on temperature. In prior art systems, the temperature sensors are prone to sense temperatures at variance from the actual temperature of the gyroscope. Such a result causes errors in the rotational calculations.
In micro-electronic designs, the proof mass of the gyrroscope is positioned and moves above a base substrate surface. Even when experiencing high G forces, the proof mass must remain above the substrate surface.

SOI-MEMS gyroscope having three-fold symmetry

United States of America as represented by the Secretary of the Army


A power operated tape measure enables extension of a tape via a drive mechanism, as well as retraction of the tape through a mechanical decoupling within the drive mechanism. The tape measure has a housing within which is positioned a spring-biased tape assembly, the drive mechanism and a clutch. The spring-biased tape assembly includes an annular reel onto which is wound a tape having indicia for taking length measurements. The drive mechanism includes a driving gear and a driven gear, and is adapted to engage with a bottom surface of the tape to extend the tape out of the housing. The clutch is adapted to displace the driven gear out of engagement with the driving gear and thereby decouple the driving and braking force provided by the drive mechanism from acting upon the bottom surface of the tape to permit the spring-biasing of the tape assembly to retract the tape into the housing.

This invention relates generally to retractable tape measurement devices. More particularly, the present invention is directed to a tape measure employing power operated tape extension that may be disengaged for retraction of the tape back into a housing of the tape measure.
Retractable tape measurement devices, or "tape measures", are well known. These tape measures generally have a housing formed by opposed sidewalls. An aperture in the housing allows an elongated tape or "blade" having measurement indicia thereon to extend out of and retract into the housing as needed. The tape is typically wound on a reel in a coil rolled manner with the reel being rotatably mounted within the housing. A first end of the tape may be attached to the reel and second free end of the tape typically has a stop or hook to prevent the second end of the tape from entering the housing. A retracting means, such as a recoil spring, is coupled with the reel to bias the reel in a direction to wind the tape onto the reel and retract the tape into the housing. A user can pull on the hook against the force of the retracting means to extend the tape out of the housing for making a measurement. A brake lever or the like may be provided so that the tape may be frictionally held at a selected position of extension while a measurement is made, and then released for retraction.
As an improvement to the operation of a conventional tape measure, power operated tape measures have been devised. The most popular design for a power operated tape measure is to include a motor that employs power operated tape extension out of the housing. This is accomplished through a gear and roller system coupled with the motor and engaging with a bottom or outwardly exposed surface of the tape as it is wound on the reel. The motor may then drive the unwinding of the tape from the reel through the gear/roller system so that the tape extends out of the housing a selected amount. Although a tape measure configured with power operated tape retraction may be implemented, such a design is often undesirable due to the complexity of employing a motor that rotates under electrical power in opposed directions to accomplish tape extension and retraction. A typical power operated tape measure, therefore, relies on a conventional recoil spring for tape retraction while utilizing a motor means for tape extension.
One design issue with tape measures having only power operated tape extension is that the gearing/rollers coupled with the motor must be disengaged from the tape surface in order for the recoil spring to accomplish quick tape retraction, i.e., without having to overcome the braking force provided by the resistance of the motor to being rotated backwardly. Various mechanisms have been employed to move a drive roller out of engagement with the tape, such as by the switch actuator and rod arrangement disclosed in U.S. Pat. No. RE37,824. However, such an arrangement is disadvantageous because as the diameter of the coiled tape becomes smaller (due to extension of a portion of the tape out of the housing), the tape driving roller must move inwardly towards the centerpoint of the reel to maintain contact with the remaining tape. This motion of the driving roller displaces the rod and actuator coupled therewith with respect to the housing, which is undesirable because the actuator does not remain in a consistent position on the housing for initiating tape retraction.

Tape measure utilizing mechanical decoupling of power tape extension feature for tape retraction


An apparatus for treatment of a failing heart by reducing the wall tension therein. In one embodiment, the apparatus includes a tension member for drawing at least two walls of a heart chamber toward each other.

The syndrome of heart failure is a common course for than progression of many forms of heart disease. Heart failure may be considered to be the condition in which an abnormality of cardiac function is responsible for the inability of the heart to pump blood at a rate commensurate with the requirements of the metabolizing tissues, or can do so only at an abnormally elevated filling pressure. There are many specific disease processes that can lead to heart failure with a resulting difference in pathophysiology of the failing heart, such as the dilatation of the left ventricular chamber. Etiologies that can lead to this form of failure include idiopathic cardiomyopathy, viral cardiomyopathy, and ischemic cardiomyopathy.
The process of ventricular dilatation is generally the result of chronic volume overload or specific damage to the myocardium. In a normal heart that is exposed to long term increased cardiac output requirements, for example, that of an athlete, there is an adaptive process of slight ventricular dilation and muscle myocyte hypertrophy. In this way, the heart fully compensates for the increased cardiac output requirements. With damage to the myocardium or chronic volume overload, however, there are increased requirements put on the contracting myocardium to such a level that this compensated state is never achieved and the heart continues to dilate.
The basic problem with a large dilated left ventricle is that there is a significant increase in wall tension and/or stress both during diastolic filling and during systolic contraction. In a normal heart, the adaptation of muscle hypertrophy (thickening) and ventricular dilatation maintain a fairly constant wall tension for systolic contraction. However, in a failing heart, the ongoing dilatation is greater than the hypertrophy and the result is a rising wall tension requirement for systolic contraction. This is felt to be an ongoing insult to the muscle myocyte resulting in further muscle damage. The increase in wall stress is also true for diastolic filling. Additionally, because of the lack of cardiac output, there is generally a rise in ventricular filling pressure from several physiologic mechanisms. Moreover, in diastole there is both a diameter increase and a pressure increase over normal, both contributing to higher wall stress levels. The increase in diastolic wall stress is felt to be the primary contributor to ongoing dilatation of the chamber.
Prior art treatments for heart failure fall into three generally categories. The first being pharmacological, for example, diuretics. The second being assist systems, for example, pumps. Finally, surgical treatments have been experimented with, which are described in more detail below.
With respect to pharmacological treatments, diuretics have been used to reduce the workload of the heart by reducing blood volume and preload. Clinically, preload is defined in several ways including left ventricular end diastolic pressure (LVEDP), or left ventricular end diastolic volume (LVEDV). Physiologically, the preferred definition is the length of stretch of the sarcomere at end diastole. Diuretics reduce extra cellular fluid which builds in congestive heart failure patients increasing preload conditions. Nitrates, arteriolar vasodilators, angiotensin converting enzyme inhibitors have been used to treat heart failure through the reduction of cardiac workload through the reduction of afterload. Afterload may be defined as the tension or stress required in the wall of the ventricle during ejection. Inotropes like digoxin are cardiac glycosides and function to increase cardiac output by increasing the force and speed of cardiac muscle contraction. These drug therapies offer some beneficial effects but do not stop the progression of the disease.
Assist devices include mechanical pumps and electrical stimulators. Mechanical pumps reduce the load on the heart by performing all or part of the pumping function normally done by the heart. Currently, mechanical pumps are used to sustain the patient while a donor heart for transplantation becomes available for the patient. Electrical stimulation such as bi-ventricular pacing have been investigated for the treatment of patients with dilated cardiomyopathy.
There are at least three surgical procedures for treatment of heart failure: 1) heart transplant; 2) dynamic cardiomyoplasty; and 3) the Batista partial left ventriculectomy. Heart transplantation has serious limitations including restricted availability of organs and adverse effects of immunosuppressive therapies required following heart transplantation. Cardiomyoplasty includes wrapping the heart with skeletal muscle and electrically stimulating the muscle to contract synchronously with the heart in order to help the pumping function of the heart. The Batista partial left ventriculectomy includes surgically remodeling the left ventricle by removing a segment of the muscular wall. This procedure reduces the diameter of the dilated heart, which in turn reduces the loading of the heart. However, this extremely invasive procedure reduces muscle mass of the heart.


A variable optical buffer queue, particularly useful either as an input or an output queue in an optical packet router in a wavelength-division multiplexing (WDM) communication network. An input queue includes plural separately controllable optical delay units disposed on wavelength channels between a demultiplexer and tunable wavelength converters controlling switching through a wavelength router. An output queue includes for each output port of a wavelength router plural separately controllable optical delay units tuned to different wavelengths. The delay units may induce selective amounts of delay and may be implemented as a series of controlled microresonators coupled to waveguide. Such a structure is usable as a controllably accessible optical memory.

1. Field of the Invention
The invention relates generally to switches used in optical communications networks. In particular, it relates to optical routers and optical buffers used therein.
2. Background Art
Two important recent advances in communication networks include large, high-capacity networks based on packet switching and optical fiber transmission media, in particular silica fiber. More recent further advances include asynchronous packet switching, such as the TCP/IP protocol of Internet networks, and wavelength-division multiplexing (WDM) of multiple optical signals on a single fiber. Combining these advances has presented difficulties.
Heretofore, the switching of asynchronous packets has been typically performed by electronic routers, which require electro-optical conversion of optical signals before and after switching. Electronic routers in WDM networks are difficult to scale to a large number of channels and present other problems of carrying different types of traffic on a large network.
An optical router is greatly desired to perform the packet switching without converting the data payload of the packet to optical form. Yoo has described such an optical router in U.S. patent application Ser. No. 09/654,384, filed Sep. 1, 2000, now issued as U.S. Pat. No. 6,519,062, incorporated herein by reference in its entirety. Yoo has also described the integration of such an optical router on a single substrate in U.S. patent application Ser. No. 10/081,396, filed Feb. 22, 2002, now issued as U.S. Pat. No. 6,768,827, incorporated herein by reference in its entirety.
A principal problem with optical routers is the difficulty of implementing optical memory, particularly random access optical memory. Some sort of memory is desired when two packets arrive on different source fibers and both require transmission to a same destination fiber, that is, memory to resolve contention. The multiple channels of a WDM fiber can alleviate some contention, but at the expense of excess capacity. TCP/IP allows some packet loss if the contention cannot be resolved, but the loss rate needs to be minimized. A feedback fiber of substantial length can be installed from the output side to the input side of the router to provide a fixed delay storage, but the feedback route complicates the router control and may contribute to further delay. Proposals have been made for parallel banks of selected fibers of different lengths. However, such an arrangement splits the optical power and requires bulky fibers.
Several approaches to packet buffering are described by Zhong et al. in "A new wavelength-routed photonic packet buffer combining traveling delay lines with delay-line loops," Journal of Lightwave Technology, vol. 19, no. 8, August 2001, pp. 1085-1092 and by Hunter et al. in "Buffering in optical packet switches," ibid., vol. 16, no. 12, December 1998, pp. 2081-2094.

All optical variable buffer queue useful in optical packet networks

The Regents of the University of California


A method and a device for controlling the slip of a tractor vehicle or the like, in which the drive wheel slip is determined and, if the actual slip is different from a specified nominal slip, the gear ratio of a controllable transmission in the drivetrain is adjusted in the direction of slip optimization. The transmission is a geared-neutral transmission whose output speed, at full drive power, can be adjusted to an extremely small value close to zero.

In this case the term "tractor vehicle or the like" is understood to mean a working vehicle in general, with which, during its operative use, high propulsion forces have to be produced by contact with the ground surface in order to generate a high thrust or traction force. As examples, agricultural tractors pulling a plow, or tractor shovels which push a loading shovel into a heap of material in order to take some of it up, may be mentioned. It is characteristic of such working processes that they take place at low driving speeds and are controlled by the driver via the control of the thrust. In known working vehicles the thrust is controlled, for example, by controlling the contact pressure in a slipping clutch, by specifying a speed difference in a hydraulic torque converter, or by means of some other torque-limiting element in the drivetrain, usually one that can be influenced by the driver.
The propulsion forces of the vehicle are produced by the contact of its tires with the ground. They depend on the normal force Fn at each drive wheel and on the coefficients of friction μ between the tires and the ground. In this, the frictional coefficient μ is particularly responsible for the forces that can be transmitted between the tires and the ground. However, the frictional coefficient itself depends on the material pairing (tire/ground) in each case and also on the slippage taking place at the wheel, i.e. the ratio between the actual speed of the vehicle over the ground and the theoretical speed on the basis of the wheel rotation speed. The known μ slip curves show that the μ value at first rises steeply with increasing slip and reaches a maximum, and then falls again along a flatter course. From this it follows that some slip is necessary in order to produce a propulsion force. The result of the μ value decrease after the maximum is that the excess drive torque not transmitted to the ground gives rise to an increasing, undesired acceleration, i.e. to wheel spin, which leads to increased tire wear and/or to damage of the road.
A method for controlling slip and a device are known from DE 102 19 270 C1. They are used with an agricultural utility vehicle which, for example, tows an agricultural implement. In this case devices are provided, which determine the slippage of the drive wheels and, if the actual slip is different from a specified nominal slip, regulate the drive torque by producing a defined combination of engine speed and gearbox transmission ratio in order to optimize the slip. A disadvantage of the known method and the known device is considered to be that in this regulation process a change of the engine speed also changes the drive torque, so that in some circumstances the power required in order to perform the given work is no longer available.

Method and device for controlling slip in a tractor vehicle or the like


The invention provides a high purity carbonaceous material which is reduced in contents of oxygen, nitrogen and chlorine readily binding to carbon atoms and in contents of elements, phosphorus, sulfur and boron, readily binding to carbon atoms upon heating and which can be used in producing single crystals such as semiconductors, a high purity carbonaceous material for use as a substrate for ceramic layer coating, and a ceramic layer-coated high purity carbonaceous material. The high purity carbonaceous material has oxygen content of 1×1018 atoms/cm3 or less as determined by SIMS. Its chlorine content is preferably 1×1016 atoms/cm3 or less as determined by SIMS, and its nitrogen content is preferably 5×1018 atoms/cm3 or less as determined by SIMS. Its phosphorus, sulfur and boron contents are preferably not higher than respective specified values. Such a high purity carbonaceous material is coated with ceramic layer.

Carbonaceous materials are not only excellent in various mechanical characteristics but also advantageous in that they hardly react with metals. Therefore, they are widely used in the semiconductor, machinery and nuclear industries.
In recent years, the market for silicon semiconductors and compound semiconductors, typically SiC and GaN has rapidly expanded. With such market expansion, the requirement imposed on carbonaceous materials have become severer. In addition, carbonaceous materials are also used in the growth of CaF2 single crystals, which are used for emitting short wavelength excimer laser beams in semiconductor lithography (hereinafter referred to as "photo etching") for attaining large scale integration of semiconductors.
Enhanced resolution is required in semiconductor photo etching and, for realizing resolution enhancement, CaF2 has come into use for emitting short wavelength excimer laser beams, such as krypton fluoride (248 nm), argon fluoride line (193 nm) nad fluorine (157 nm). In connection with this, lenses made of fluorite (single crystal CaF2) have come into use, since the conventional noncrystalline optical materials cannot transmit light at 193 nm. In the following, the production of CaF2 single crystals is described specifically. CaF2 single crystals are produced by the Bridgman technique of Czochralski (CZ) process. The use of a graphite material as jigs in furnaces, such as heating elements, in the production of CaF2 single crystals by the Bridgman technique, for instance, is described in Laid-open Japanese Patent Application (JP Kobai) No. 2000-137101.
Graphite materials generally contain metal impurities entrapped in pores and between graphite lattices thereof, hence they as such cannot be used in semiconductor manufacturing. Therefore, the applicants have previously proposed, for use in the semiconductor and nuclear industries, high purity graphite materials having a metal impurity (ash) content of 5 ppm or less as a result of treatment of graphite materials with a halogen-containing gas, for instance, for attaining high levels of purity (JP Kokai No. S64(1989)-18964; Japanese Patent Publication (JP Kokoku) No. H06(1994)-35325). They have also recently proposed, in JP Kokai 2002-249376, carbonaceous materials with reduced nitrogen content for use in the manufacture of compound semiconductors.
However, even if such high purity graphite materials reduced in metal impurity content and in nitrogen content as disclosed in the above-cited patent documents are used as jigs in furnace, the yield in the production of CaF2 single crystals becomes very low, less than 10%, because impurities, such as oxygen, chlorine, phosphorus and sulfur, have an unfavorable effect.
An object of the present invention is to provide the high purity carbonaceous material, which have not only reduced oxygen, nitrogen, chlorine, phosphorus and sulfur content in pores, but also reduced amounts of oxygen, nitrogen, chlorine, phosphorus, sulfur and boron which are bound to carbon atoms in graphite material.

High purity carbonaceous material and ceramic coated high purity carbonaceous material