A method of controlling charge or discharge of a battery for an electric vehicle comprises the steps of, dividing a battery into a plurality of blocks each composed of a plurality of cells for constituting the battery in all, detecting terminal voltages (V.sub.n) of the divided blocks, respectively to obtain a difference (V.sub.max -V.sub.min) in voltage between a maximum value and a minimum value from among the detected terminal voltages of the respective divided blocks, and controlling the charge or discharge of the battery on the basis of the obtained difference in voltage between the maximum and minimum values of the terminal voltages of the divided blocks. In practice, when the voltage difference (V.sub.max -V.sub.min) between the maximum value and the minimum value is equal to or higher than a specified value (V.sub.Kc, V.sub.Kd), the battery is stopped from being further charged or discharged; the charge or discharge current is limited; or the charge or discharge current is decreased stepwise at each control start period, to prevent the low-performance cells from being overcharged or over-discharged, that is, for prevention of the partial cells from being deteriorated due to a performance difference between the respective cells.

1. Field of the Invention
The present invention relates to a battery charge/discharge control method for an electric vehicle, more specifically to a method of controlling charge or discharge of a battery for the electric vehicle to prevent the battery from being overcharged or over-discharged due to difference in performance among battery cells for constituting the car battery.
2. Information Disclosure of the Related Art
In general, a battery mounted on an electric vehicle is of secondary battery which can be charged and discharged repeatedly. Therefore, when the remaining battery capacity decreases, it is necessary to take an appropriate control or management action before being over-discharged, for instance by charging the battery under restriction of charging current.
Various technique related to the battery charge/discharge control method has been so far proposed. For instance, Japanese Patent Application Laid-Open (Kokai) No. 60-245402 discloses such a battery charge/discharge control method that when any one of the battery open voltage and the battery voltage during vehicle travel drops below a predetermined voltage, respectively, an alarm is generated to inform the driver of a decrease in battery capacity, and in addition the battery capacity and the battery life can be both displayed by detecting the time required until the battery voltage reaches a constant voltage level when charged. By the way, in the electric vehicles, since a relatively high voltage is required as a power source for driving the vehicle, the battery used as the primary power source is usually formed by a combination battery such that a plurality of unit batteries each composed of a plurality of cells are combined with each other. In the case of a lead battery, for instance, a unit battery of nominal 12 V (.apprxeq.2.1 V.times.6) is composed of six cells of 2.1 V, and a battery of nominal 336 V (=12 V.times.28) can be obtained by connecting 28 unit batteries in series. Therefore, the total number of this battery cells is as large as 168 (=6.times.28).
As a result, in the conventional battery charge/discharge control technique of detecting the terminal voltage of the whole battery cells to control the charge or discharge of the battery, since the partial battery cells tend to be overcharged or over-discharged due to difference in performance among the cells during the charge and discharge operation, there exists a problem in that the battery performance deteriorates or damaged, with the result that the battery life is shortened. In addition, once a difference among the individual cells begins to occur due to over-discharge, the battery performance deteriorates sharply with the lapse of time.

Battery charge/discharge control method for electric vehicle


The invention provides a method for decoration of silver onto carbon materials, comprising the following steps: functionalizing a first carbon material and a second material; mixing the functionalized first and second carbon materials into a first mixed solution through an alcohol solution; and mixing a silver solution and the first mixed solution into a second mixed solution.

1. Field of the Invention
This application claims priority of No. 101138167 filed in Taiwan R.O.C. on Oct. 17, 2012 under 35 USC 119, the entire content of which is hereby incorporated by reference.
The invention relates to a method for decoration of silver, particularly to a method for decoration of silver onto carbon materials.
2. Related Art
In the current field of the transparent conducting oxide, indium tin-doped oxide (ITO) is the most research and industrial application.
However, ITO is exposed to aerobic high-temperature (about 300° C.) environment, conductivity of ITO will significantly decrease because of oxygen vacancy. Moreover, the amount indium metal is continuing to decrease and difficult to obtain, price of indium metal will continue to rise, it will also cause the cost of transparent conductive film to increase year by year.

Method for decoration of silver onto carbon materials


A cleaning/polishing pad has a first surface with raised, substantially nubs, having a length greater than a width, arranged adjacent each other forming laterally alternating rows of nubs and having troughs interspersed therebetween, a second surface opposite the first surface, and a thickness. The troughs, which may contain polishing/cleaning chemicals, are divided into first and second groups of substantially parallel troughs. The groups of troughs are arranged at an angle to one another forming a hatch pattern. The pad can be formed to make roller brushes, circular brushes or manual wipes. For the circular brushes the nubs are arranged adjacent each other forming laterally alternating concentric circles of nubs. Micropores are interspersed within the pad having a gradient of pores with smaller pores towards the first surface and larger pores towards the second. There are no sharp edges or corners in/on the pad.

The present invention generally relates to cleaning and polishing devices for use in critical environments, and in particular, to a cleaning/polishing pad which has a selected surface pattern for use as a circular or roller brush and as a manual wipe, and a method for using the pad.
Many industrial operations, especially in semiconductor manufacturing operations, require efficient means to polish and clean highly finished surfaces. Semiconductor materials, such as silicon wafers, require the removal of particulates and other surface contaminants during the manufacturing processes. Other materials, such as optical glass or magnetic storage devices, also require similar removal of particulates and other surface contaminants. In particular, operations in semiconductor device fabrication often utilize a two-step process that includes a polishing step followed by a brushing step. One of the main goals of the polishing step is to planarize the wafer, while the main goal of the brushing step is to perform subsequent cleaning of the wafer. These two-steps are often repeated followed by the addition of semiconductor material in order to manufacture a semiconductor material having multiple polished layers. It is essential that particulates and surface contaminates be removed between the layers to avoid defects in the final product.
In the manufacturing of integrated circuits, chemical mechanical polishing has emerged as the preferred approach to achieve both local and global planarization. These techniques typically use a polishing pad along with a polishing slurry. The brushing step, which follows chemical mechanical polishing, typically involves cleaning fluid and a brush device having a sponge-type cleaning pad.
Popular brushes, rollers, sponges and other wiping products made from non-woven, woven or knit materials, typically used in industrial and critical environments, are inadequate to address the higher levels of cleanliness and absorbency required in cleaner environments. Unfortunately, fiber particulates and certain free polymers found on conventional wiping products, frequently contaminate the processes, tools and facilities. In addition to the surface of the manufactured item, the environment and work surfaces in microelectronic firms are susceptible to such contamination. Prior art wipes, sponges or brushes, which have conventional nubs, damage surface features and are very poor at delivering cleaning chemicals to the surface of wafers and other media. Other prior art wipes, sponges or brushes contain chloride and other biocides which are corrosive to disk media surfaces. Also, undesirable metallization of semiconductor wafers might occur when metal particulates are produced by conventional wiping products. Furthermore, silicone has also been used when cleaning, but is not permitted with semiconductor wafers as it is detrimental to the surface of the wafers. Therefore, silicone is not permitted in any product used in the cleaning process.
One method for cleaning wafers involves pads that contact and clean the wafer as they rotate. U.S. Pat. No. 5,778,481 (""481), assigned to International Business Machines Corporation, describes disc shaped cleaning/polishing pads having resilient members (nubs) arranged in patterns (spiral, swirl, concentric or the like) which facilitate the movement of cleaning/polishing fluids from the center of the pads to the periphery. The pads of the ""481 patent may be composed of suitable materials such as polyurethane or polyvinyl alcohol.
Likewise, U.S. Pat. No. 5,311,634, issued to Nicholas Andros, describes disc shaped cleaning pads for use on a cleaning apparatus, which consist of a supporting core with a sponge affixed thereto which is a microporous hydroxylated polymer material; the surface of the sponge is convex having a plurality of projections which are preferably a plurality of hemispherical nubs arranged in concentric circles, which may also be ellipsoid, cubic, conical or a variety of other shapes, radiating from the central axis of the sponge.
Furthermore, U.S. Pat. No. 5,966,766, assigned to Advanced Micro Devices, Inc., shows a method and apparatus for cleaning a semiconductor wafer that includes a disc-shaped brush which is a substantially flexible material having a plurality of protrusions thereon; the protrusions are designed to extend through corresponding openings in a disc shaped base wherein the protrusions are spaced apart.
Alternative methods involve the use of sponge or sponge-like rollers for automated machinery, and wipes to manually clean surfaces. U.S. Pat. Nos. 6,004,640 and 5,460,655, assigned to Wilshire Technologies, Inc., disclose a hydrophilic foam article and surface-cleaning method for a clean room which article is made from an open cell, static-dissipative, polyurethane foam and laundered in deionized water, and can be fashioned as a wiper, a sponge, a roller, a swab mounted on a handle, or a plug having a generally cylindrical shape.
Also, U.S. Pat. No. 6,004,402 (""402), assigned to Xomed Surgical Products, Inc., shows a method of cleaning silicon material with a sponge in which the sponge is purified to remove undesirable residual contaminants. The sponge of the ""402 patent has 100% open pores and no dead ends or fibrils. Furthermore, the sponge therein also has conical projections extending from the outer surface. The projections are disposed at regular intervals in rows offset from one another in the direction of the longitudinal axis, and have planar surfaces, which are smaller than their bases.
U.S. Pat. No. 4,566,911 (""911), assigned to Kanebo Limited, describes a method for cleaning an article using a cleaning roll having a surface layer of polyvinyl acetal porous elastic material. The roller of the ""911 patent may have a smooth surface, a gear-like surface with parallel groves which may form an angle to a roll axis, or projections extending from the surface in which the projections may be circular, ellipsoidal, rectangular, or diamond shape or the like which covers a surface area of 15% to 65% of the entire surface area. The articles of the ""911 patent is not designed for use in a critical environment.
None of the above inventions and patents, taken either singularly or in combination, is seen to describe the instant invention as claimed.
Cleaning pads of the present invention may be used in brushes which are used in chemical mechanical planarization washing, wet bench photoresist, etching techniques, spin drying, disk media washing, substrate washing, and other microelectronic/optical washing and drying processes. Alternatively, the cleaning pads may be used as manual abrasive and wiping pads which are used to apply or remove cleaning chemicals, debris, residues and particles, and to dry surfaces by hand. The cleaning pads facilitate the application of cleaning/polishing chemicals via external delivery, internal delivery, and submerged into the cleaning chemicals.
It is an object of the present invention to provide a cleaning pad surface which generates turbulence in the fluid cleaning chemicals as the pad is moved across a substrate. The cleaning pad of the present invention has at least one surface designed to contact the item to be cleaned. This surface has evenly distributed nubs with troughs interspersed between the nubs. When properly used, the nubs agitate the fluid cleaning chemicals creating sufficient agitation to remove particulates from the item.
A further object of the present invention is to provide a cleaning pad which permits fluid to be dispersed through the pad or to wick into the pad. The present pad has a micropore structure which is open-celled having very fine pores on the order of 2-5 microns. These pores permit the cleaning fluid to be dispersed and removed through the pad. This attribute permits control of the amount of cleaning chemicals present.
Another object of the present invention is to increase the absorbency of cleaning pads or wipes for clean environments. The absorbency of a cleaning pad according to the present invention may be selectively controlled with automated systems. Otherwise, the cleaning pads according to the present invention are highly absorbent.
Yet another object is to control the delivery of cleaning chemicals. The open-cell core of the pad permits even flow of cleaning chemicals, which flow can be modulated by applying a vacuum or pressure across the opposing side of the pad. The present invention facilitates delivery of cleaning chemicals continuously on and into the face of the wafer with higher rates of turbulence and greater flushing and drawing of debris, residues and particles than prior art articles.
A further object of the present invention is to improve the longevity of cleaning pads as long-term disposables. The pads of the current invention have a longer life than prior art cleaning wipes/sponges but are still disposable. The prior art devices have sharp or squared edges which catch on rough substrates resulting in torn wipes or sponges. The pads of the present invention have no sharp or squared edges, and therefore do not tear easily.
Another object of the present invention is to eliminate fiber release from fiber based wiping materials. The uniformity of cells prevents dry spots which might otherwise result in subsequent abrasion that shortens the life of the brush. Also, uniformity limits the transmission of brush particles to the wafer.
It is also an object of the present invention to reduce damage to the item cleaned. Sharp edges are avoided in the present invention, as previously mentioned, which reduces scratching of the item cleaned. Prior art articles have sharp edges which are especially undesirable in the manufacture of semiconductor materials, especially silicon wafers. The nubs on the cleaning pads of the present invention have rounded edges and corners thus eliminating this potential source of scratches.
These and other objects of the present invention will become readily apparent upon further review of the following drawings and specification.


An image forming apparatus capable of forming both of erasable images and images to be stored, and increasing the number of times that a single sheet with an image can be repetitively decolorized and reused. The apparatus includes a photoconductive element for electrostatically forming a latent image representative of image data. A developing device develops the latent image formed on the photoconductive element by either of an ordinary undecolorizable toner and a decolorizable toner.

The present invention relates to an image forming apparatus capable of forming an erasable image and, more particularly, to an image forming apparatus for forming an image on a sheet by a decolorizable toner.
There has recently been reported a decolorizable toner which becomes transparent when illuminated, heated or otherwise treated. For example, a toner in which a functional infrared absorptive coloring matter IR820B and ammonium salt of organic boron, e.g., tetrabutyl ammoniumbutyl triphenylborate are coexistingly dispersed is taught in "Functional Coloring Matter Sectional Meeting, Data No. 17", Functional Coloring Matter Sectional Meeting of the Kinki Institute of Chemical Engineers, May 29, 1991. A decolorizable toner reactive to light appears blue before decolorization and exhibits the maximum absorption for a wavelength of 825 nm. When illuminated by infrared rays having a wavelength range close to 825 nm or light containing such infrared components (e.g. light from a halogen lamp), the decolorizable toner becomes transparent. Therefore, by decolorizing a decolorizable toner image existing on a sheet, it is possible to use the sheet repetitively. This effectively saves limited natural resources. Let the toner made transparent by decolorization be referred to as a transparent toner hereinafter.
The decolorizable toner becomes transparent when subjected to light or heat. Hence, when a sheet carrying a toner image formed by a decolorizable toner sensitive to light is left in a light place, the toner image sequentially fades and, finally, becomes transparent. Also, a decolorizable toner image sensitive to heat becomes transparent when stored in a hot place. For this reason, the decolorizable toner is not feasible for images containing important data. It follows that if an image forming apparatus is operable only with a decolorizable toner, images to be stored have to be formed by another and exclusive image forming apparatus.
Moreover, although decolorization makes a decolorizable toner forming a toner image on a sheet transparent, it does not remove the toner image from the sheet; that is, the transparent toner image remains on the sheet even after decolorization. As a result, the amount of transparent toner the remaining on the sheet sequentially increases as the sheet is repetitively used, resulting in various problems, as follows. When a toner image is to be transferred to the sheet by a new image forming step, the transparent toner remaining on the sheet causes the image to be irregularly transferred, locally lost, or otherwise damaged. Further, the sheet with the transparent toner remaining thereon is apt to jam the transport path. In addition, in the event of fixation, hot offset or similar defects may occur. Therefore, despite decolorization, the number of times that a single sheet can be repetitively used is limited. Generally, the maximum number of repetitive use of a single sheet is considered to be 10 times at most.

Image forming apparatus capable of forming an erasable image


Disclosed are an extendable pressurized-type hollow fiber membrane module which facilitates improvement of filtrate quality through a multistep-filtration, enhanced easiness of installation and maintenance, decrease of footprint, and/or enlargement of filtration apparatus (without causing decrease of permeate flux of a unit hollow fiber membrane), and a filtration apparatus manufactured using the same. The filtration apparatus of the present invention comprises first and second pressurized-type hollow fiber membrane modules, wherein an inlet port of the first pressurized-type hollow fiber membrane module for introducing feed water and an outlet port of the second pressurized-type hollow fiber membrane module for discharging filtrate or air are coupled to each other.

Separation methods for water treatment include a method using heat or phase-change, a method using a filtering membrane, and so on. Among the advantages of the method using a filtering membrane is the high reliability of water treatment since the water of desired purity can be easily and stably obtained by adjusting the pore size of the filtering membrane. Furthermore, since the method using a filtering membrane does not require a heating process, it can be used together with microorganisms which are useful for separation process but vulnerable to heat.
Among the methods using a filtering membrane is a method using a hollow fiber membrane module comprising a bundle of hollow fiber membranes. Typically, a hollow fiber membrane module has been widely used in the field of microfiltration for obtaining axenic water, drinking water, super pure water, and so on. Recently, the application of the hollow fiber membrane module is being extended to wastewater treatment, solid-liquid separation in a septic tank, removal of suspended solid (SS) from industrial wastewater, filtration of river, filtration of industrial water, filtration of swimming pool water, and the like.
The hollow fiber membrane module may be classified into a submerged-type module and a pressurized-type module in accordance with the driving method.
The submerged-type module performs the filtration operation while submerged in a water to be treated. Particularly, as the negative pressure is applied to the inside of the hollow fiber membrane, only the fluid component is allowed to pass through the hollow fiber membrane and enter the inside (lumen) thereof. As a result, the pollutants such as the impurities and sludge contained in the water are separated from the filtrate. The submerged-type module is advantageous in that it does not require additional facilities for circulating the water, and thus the cost of equipment itself as well as the operation cost can be reduced. On the other hand, it has a drawback in that the permeate flux obtainable per a unit time is limited.
On the contrary, although requiring additional facilities for circulating the water, the pressurized-type module pressurizing the water from the outside to the inside of the hollow fiber membrane is advantageous in that its permeate flux obtainable per a unit time is greater than that of the submerged-type module.
As illustrated respectively in the Korean patent application laid-open publication Nos. 10-2012-0122381 and 10-2012-0140329 filed by the present applicant, in a conventional pressurized-type hollow fiber membrane module, both ends of a hollow fiber membrane disposed inside a case are potted in different fixing parts respectively. In other words, since the body portion of the hollow fiber membrane performing a filtration process is positioned between the two fixing parts in the case, when the hollow fiber membrane is damaged, it is impossible to repair it, and thus the entire module should be discarded.
In order to increase the treatment capacity of the filtration apparatus, it may be considered to increase both lengths of the case and hollow fiber membrane therein. The longer the length of the hollow fiber membrane is, however, the greater the frictional force which prevents the filtrate flow along the lumen of the hollow fiber membrane is, thereby decreasing the permeate flux of the hollow fiber membrane.
As another method to increase the treatment capacity of the filtration apparatus without increasing the length of the hollow fiber membrane, it may be considered to connect a plurality of pressurized-type modules in parallel. Such method, however, requires more complicated water-circulating facilities, and thus makes it more difficult to install a filtration apparatus. Furthermore, it also requires the increase of footprint of the filtration apparatus.

Extendable pressurized-type hollow fiber membrane module and filtration apparatus manufactured using the same


The fuel assembly has fuel arrangement of a square lattice of 10 lines by 10 rows. Four water rods having a large diameter are arranged in central region of horizontal cross section wherein arrangement of 12 fuel rods is possible. The four water rods having a large diameter are so arranged adjacently in a circle as to form an internal between each other. First coolant flow path which is extended toward axial direction is formed by surrounded with the water rods having a large diameter. The first coolant flow path leads to third coolant flow path which is formed around the fuel rods through second coolant flow path which is the interval between the water rods having a large diameter.. The fuel assembly is able to optimize the moderator to fuel atom number density ratio and to reduce the pressure loss because a portion to be an excessively moderated region is utilized as the first coolant flow path.

The present invention relates to a fuel assembly and an upper tie plate thereof, and specially to the fuel assembly and the upper tie plate thereof which are preferable for effective utilization of fissile material and achieving high burnup in boiling water reactors.
Improvement of fuel economy is able to achieved by increasing the degree of burnup of the fuel. For increasing the degree of burnup of the fuel, enrichment of uranium 235 in the fuel pellet may be increased. But, increasing of the enrichment without increasing of the moderator to fuel atom number density ratio (H/U ratio) causes hardening of a neutron spectrum. Therefore, an finite multiplication factor of the fuel assembly does not become the maximum value at the enrichment.
FIG. 1 illustrates change of the relation between the H/U ratio and the infinite multiplication factor depending on increasing of the enrichment. For obtaining large infinite multiplication factor with a constant enrichment, it is necessary to achieve the most proper H/U ratio corresponding to the enrichment. That is, when the enrichment is increased in order to improve the fuel economy, the most proper H/U ratio is increased, and accordingly it becomes necessary to increase the number of water rods or to increase a horizontal cross sectional area of the water rods.
And, when the enrichment is increased, power peaking in radial direction of the fuel assembly is increased and linear power density of fuel rod becomes large, and consequently the fuel rod is exposed to a more severe condition.
Further, distribution of voids in axial direction of the reactor core is small at the lower end portion of the reactor core, and is large from the middle to the upper end portion of the reactor core. Therefore, as burning of the fissile material at the upper region of the fuel assembly is retarded, the concentration of uranium 235 becomes higher relatively than that in the other portion. And by effect of the void, fissile plutonium is produced and built up at the upper region of the fuel assembly. According to the reason mentioned above, power peaking becomes high at the upper portion in axial direction of the fuel assembly. As the increasing of the enrichment relates also to the increasing of power peaking in the axial direction, linear power density of the fuel rod becomes large as well, and the fuel rod is exposed to a more severe condition.
On the other hand, a flow rate spectral shift operation of a nuclear reactor is currently considered, in which the void fraction is changed greatly by operating the nuclear reactor with smaller flow rate (the flow rate of the coolant which flows through the reactor core) in the reactor core than the designed flow rate value at the beginning of operation cycle and with larger flow rate in the reactor core than the designed flow rate value at the end of the operation cycle, and fissile plutonium is built up and burnt effectively. In performing the flow rate spectral shift operation, as the power peaking in axial direction becomes large, the linear power density of the fuel rod becomes larger and the fuel rod is exposed to a more severe condition.
Accordingly, in order to decrease the linear power density of the fuel rod and to be sure to maintain thermal margin, it is necessary to reduce the power load per fuel rod by increasing number of the fuel rods in the fuel assembly by such method as changing the configuration of a fuel rods lattice from 8 lines by 8 rows to 9 lines by 9 rows etc.
In view of the two aspects described above, increasing of the number of fuel rods in the fuel assembly by changing the configuration of the fuel rods lattice and increasing of the H/U ratio by increasing of horizontal cross sectional area of the water rod or number of the water rods are a current trend in the fuel assembly for boiling water reactor.
For instance, in U.S. Pat. No. 4,781,885, a fuel assembly having a fuel rods lattice of 9 lines by 9 rows is disclosed, in which a large square water rod is installed at the central region which is equivalent to the 9 fuel rods arranged in a square lattice of 3 lines by 3 rows.
Further, in JP-A-1-196593 (1989), a fuel assembly having fuel rods in diamond lattice of which bearings to the internal wall of the channel box is 45.degree. is disclosed, in which a cruciform large water rod is installed at the central region which is equivalent to a region for 12 fuel rods.
More plutonium is built up generally at the upper region of the fuel assembly as described above, especially in case of the flow rate spectral shift operation, much plutonium are built up. When the quantity of plutonium built up at the upper region of the fuel assembly is increased so much, it becomes difficult to maintain surely the margin of the reactor shut down at cold shut down. The difficulty is caused by increasing of the infinite multiplication factor with disappearance of voids at the upper portion of the reactor core at the cold shut down.
In order to solve the problem, in JP-A-64-88292 (1989), a plurality of water rods are installed at least in symmetrical positions to the diagonal line of the fuel assembly and fuel rods having shorter length in axial direction than the other fuel rods (partial fuel rod) are installed at least at the position between the water rods. In the fuel assembly, the void fraction of coolant at the space above the partial fuel rods where the fuel is not located, namely vanishing rods, becomes zero at the cold shut down of the reactor. The portion of the vanishing rod acts as a large water rod with the other water rods at the cold shut down. Therefore, the portion of the vanishing rod has an excessive neutron moderating effect and reversely a large neutron absorbing effect at the cold shut down. As the result, the difference between the infinite multiplication factors during the operation of the reactor and during the cold shut down becomes small, and shut down margin of the reactor is increased. Further, in the case of installing of the partial fuel rods, an additional effect such as reducing of pressure loss at two phase flow portion in the fuel assembly under the reactor operation is brought.
As described above, increasing of the H/U ratio by increasing of the number of fuel rods, and further, increasing of horizontal cross sectional area of the water rods or the number of the water rods are the current tendency.
Under such trend of the current technical development, a trial is performed which is aimed at high burnup by increasing the enrichment further. Such increment of the enrichment aiming at the increasing of the discharge burnup necessitates further enlarging of the horizontal cross sectional area of the water rods in order to make the H/U ratio the most proper. Nevertheless, as the horizontal cross sectional area of the large water rod is enlarged according to U.S. Pat. No. 4,781,885 and JP-A-1-196593 (1989), the pressure loss of the reactor core is increased by narrowing of the area of the coolant flow path which is formed between the fuel rods.
The increasing of the pressure loss of the reactor core is a problem mainly in following points.
(1) When the pressure loss of the reactor core is increased, the capacity of the pump has to be increased in order to compensate the increment. If the maximum flow in the reactor core is achieved by the maximum rotation of the pump under the condition without the increment of the pressure loss, the pump is not able to achieve the maximum flow in the reactor core when the pressure loss is increased.
(2) Stability is lowered by increasing of the pressure loss. That is, as the pressure loss of the two phase flow in the upper portion of the fuel assembly is larger than the pressure loss of the single phase flow portion, when entering flow to the fuel assembly is increased, the resistance at the two phase flow portion is increased in order to reduce the entering flow. When the entering flow is reduced, the resistance at the two phase flow portion is reduced and the entering flow is increased again. By repeating of the phenomena, vibration of the flow is caused in the fuel assembly, and the stability is lowered. The larger the pressure loss at the two phase flow portion is, the easier the vibration of the flow is caused.
On the other hand, the fuel assembly which is described in JP-A-64-88292 (1989) has a problem in aspect of fuel economy because optimization of the H/U ratio is not considered on the fuel assembly.
Further, in case of installing partial fuel rods, which has two advantages such as the reduction of pressure loss at two phase flow portion and the secureness of the reactor shut down margin into the fuel assembly for high burnup as described in JP-A-64-88292, fuel inventory is decreased. The reduction of the fuel inventory increases the number of reload fuel assemblies and causes problems such as increment of the number of generated spent fuel assemblies. One of the methods for solving the problem is enlarging the diameter of the fuel rod for keeping the same fuel inventory as before installing of the partial fuel rod. But the method causes another problem of increasing pressure loss which is accompanied with the reduction of flow path area for the coolant.

Fuel assembly and upper tie plate thereof


This invention relates to a keyboard cleaning device. More particularly, this invention relates to a device for cleaning upper and/or lateral surfaces of keyboard buttons or keys. In a first embodiment of the present invention, a key cleaner is comprised of a head structure having at least one convex cleaning substructure contoured to the top surface of a key of a data entry keyboard, a handle and means for attaching the handle to the head structure. Pursuant to a second embodiment of the present invention, the key cleaner is comprised of a head structure having at least one wedge-shaped cleaning substructure which is contoured to fit between the keys of a data entry keyboard and a handle attached to the head structure. Other embodiments are also described.

This invention relates to a keyboard cleaning device. More particularly, this invention relates to a device for cleaning upper and/or lateral surfaces of keyboard buttons or keys including keys on computer, typewriter, machine-operator console and cash register keyboards.
Computing and word processing systems have made data entry keyboards ubiquitous in the private sector, government and home. Data entry keyboards are now commonly used by data-entry personnel, secretaries, receptionists, programmers, clerks, computer-controlled machine operators, and others. Data entry keyboards are now even used on many cash registers. Use of these keyboards will grow as the role played by computers in modern society increases.
To input data into a computer, cash register or other device, the user touches the keys of a data-entry keyboard with the fingertips. Through frequent contact, the upper key surfaces tend to accumulate a coating of grease. This provides a favorable medium for collecting dirt and dust within the work area. The dirt and dust also accumulates on the side surfaces of the keys over time. This accumulation may be exacerbated by a number of users having access to a keyboard or any one user eating or drinking in the vicinity of the keyboard.
Dirt on the keys of a keyboard gives an unpleasant appearance and feeling which can have a negative effect on the productivity and satisfaction of the keyboard user. Accumulation of dirt, grease, food or soda can actually make the keys stick, causing an increased chance of data-entry error. On data-entry keyboards associated with cash registers, caked on grease and dirt are especially problematic.
Presently, there is no commonly available tool or easy method to facilitate the cleaning of keyboards. Present methods of cleaning keyboards are awkward, tedious and ineffective. Keyboard users allow dirt to accumulate on the keys to the point such dirt negatively impacts productivity and increases the potential for damage to the internal workings of the keyboard.
The most common current method of cleaning the keys is to rub the upper surface of the keys with tissue paper sprayed with an office furniture cleaner. This method is clumsy and crude, even for the upper key surfaces. The lateral key surfaces are very difficult to reach using this method.
Recently, cotton swab-like devices have become available in professional cleaning kits, or through computer supply distributors. These devices may be used to clean the upper key surfaces, but are not much better than tissue paper. In addition, these devices are inadequate for cleaning the lateral surfaces of the keys.
Other approaches to cleaning keys involve blowing the keys with compressed air or exposing the keys to suction with a miniaturized vacuum. These approaches are not effective because most of the dirt that accumulates sticks to the keys. The dirt is not susceptible to low-level air pressure or suction.
It is, therefore, a principal object of the present invention to provide a simple device and a method for inexpensively, rapidly and effectively cleaning the keyboards of data entry equipment. An additional, more particular object of the present invention is to provide such a device for effectively cleaning both the top and lateral surfaces of keys of data-entry keyboards.
It is an additional object of the present invention to provide a device for cleaning more than one key on a data-entry keyboard at the same time. It is a further object of the present invention to provide a device that can both clean data entry keyboards and dry them off after an initial cleaning step is performed. It is a further object of the present invention to provide a method for cleaning and drying the keys of data entry keyboards.
These and other objects of the present invention will be understood from a consideration of the specification and the drawings which are attached hereto.


A method for the recovery of hydrocarbons from a reservoir of hydrocarbons including injecting a hydrocarbon solvent into the reservoir along with a displacement gas to mobilize hydrocarbons in the reservoir of hydrocarbons; and producing mobilized hydrocarbons from the reservoir of hydrocarbons. The hydrocarbon solvent is injected along one or more predominantly horizontal injection wells in the aquifer that are spaced from the production well or wells. The hydrocarbon solvent is a hydrocarbon solvent selected from the group consisting of ethane, propane, butane. Apparatus for the recovery of hydrocarbons from a reservoir of hydrocarbons includes at least a first and preferably several injection wells drilled into the reservoir, the injection wells having a portion open to fluid communication with the reservoir; and at least a first production well and preferably several production wells drilled into the reservoir, and spaced below the injection wells, the first production well including a pump for pumping oil from the well. A solvent recovery system is also preferably connected between adjacent injection wells and production wells.

The recovery of heavy oils using horizontal wells has been carried out on an increasing scale in Canada and other countries in recent years. Typical practice in fields such as those in Winter, Senlac, Long Lake, Cactus Lake and Haytar, all in Canada, involves the construction of horizontal production wells about 1000 m in length at the top of the reservoir. Oil is produced by pumping and the recovery is limited eventually by the watering out of the production. Water displaces and replaces the oil as it rises from aquifers lower in the reservoir. The advantage of horizontal wells over conventional, near-vertical ones is that the volume of the reservoir affected by the rising water is much greater and oil is drawn by each well from a larger area. In favourable cases, cumulative production quantities of 100,000 barrels or more of oil are achieved at economic production rates. These are sufficient to more than pay for the cost of the horizontal well and its operation. The disadvantage of the process is that a recovery of only about 5% of the oil in place is achieved. Much of the original oil is left behind in the unswept and water-swept regions.
The inventor has previously proposed an approach for the recovery of heavy oils that involves the use of vaporized solvents such as ethane, propane, or butane. In this method use is made of gravity to cause the oil diluted by the solvent to fall to the base of the reservoir with its initial pore volume becoming filled by solvent vapor. The process is effective if appropriate reservoir conditions can be achieved. In particular, for economic application of the process, it is necessary to have a large mass transfer area available since diffusive mixing is slow. The pressure needs to be close to the vapor pressure of the injected solvent since light hydrocarbon vapors only have a high solubility in the oil when they are close to their dew point. This limited the most economic applications of the process to reservoirs where the pressure can be controlled appropriately, i.e. to about 500 psig for ethane, 110 psig for propane and 20 psig for butane.
Propane has a particular advantage as a solvent for use in such recovery techniques because it allows the precipitation of considerable asphaltene material in the reservoir thus producing an upgraded, less viscous, and more valuable oil product. For propane to be used by itself at normal reservoir temperatures a pressure of the order of 110 psig is required.
In a previous application for patent, the inventor proposed a process that uses saturated hydrocarbon solvent vapor (typically ethane or propane) in conjunction with horizontal wells to mobilize and recover viscous oils and bitumens from reservoir of hydrocarbons in which a bottom water zone (aquifer) is used to deliver the solvent vapor to the base of the reservoir. A hydrocarbon solvent in the vapor phase is preferably injected at reservoir temperature into an aquifer underlying the deposit. The hydrocarbon solvent vapor is essentially insoluble in water, while strongly soluble in oil, with the consequence that there are no heat or material losses to the water layer. Furthermore, the water in the bottom water zone will be mobilized and underride the lighter diluted oil and assist in moving it towards the production well. Use of this process produces a much larger interfacial area for mass transfer. However, the pressure requirement probably limits the general applicability of using propane alone in such a method to relatively shallow bitumen reservoirs.
In this patent document, a further improvement of the above described hydrocarbon recovery process includes the injection of a non-condensible displacement gas into a reservoir with a hydrocarbon solvent. The displacement gas should be at a pressure sufficient to limit the rate of ingress of water into the recovery zone to a small manageable value. The process is operated so that some of the injected displacement gas is produced from the horizontal production wells located at the base of the reservoir. The injection may be into the bottom water layer if this exists or, if it is practical (as it usually will be with conventional heavy oils but not with bitumen), into horizontal injection wells located at the top of the reservoir, parallel to and probably displaced horizontally from the producers. Gas is injected into the reservoir from these wells and the production is controlled so that there is a net but manageable small flow of gas from injector to producer. In conventional reservoirs such an operation may produce a small recovery of heavy oil by itself, but this will be limited because of the tendency of the low viscosity gas to flow through the oil as fingers and bypass it. The hydrocarbon solvent should be a liquefied but vaporizable solvent such as butane or propane. Confined evaporation of this liquid solvent in the displacement gas maintains a concentration of solvent vapor in the gas phase. The rate of injection of liquefied solvent is preferably controlled so that essentially all of the solvent is vaporized before the gas stream reaches the production well. This vaporized solvent diffuses within the gas fingers and dissolves into the heavy oil reducing its viscosity. The diluted oil becomes mobile and accumulates at the bottom of the gas fingers so as to tend to seal them off. However the steady flow of gas results in displacement and diluted oil is produced. The rate of injection of liquefied solvent is controlled so as to maintain a practical concentration in the produced oil (2-50% by weight).
A limitation of this approach can be that the fingers of gas produced by the initial injection sweep only a small volume of the reservoir and, as a result, there is only a limited interfacial area for the solution of the vaporized solvent into the bitumen. Mixing is limited and, as a result, the production rate may be limited. Therefore, in a further aspect of the invention, use is made of the flow channels that have been developed in a reservoir that has been previously produced by conventional water displacement of the type described above. In the water-flooded reservoir there are numerous passages in which water has been flowing through the oil sand. In this further aspect of the invention, the displacement gas is injected with liquefied but vaporizable solvent into the horizontal well(s) already located at the top of the reservoir and to displace the water downwards to new horizontal production wells drilled at the base of the reservoir, parallel to the injectors. The producers may be located directly below each injector or in between. Non-condensible gas is allowed to flow through these interconnected passages and to displace water to the production well. Again, as in the previous processes, the pressures are arranged so that there may be a small inflow of fluids from outside the recovery region but only at a controllable rate. The liquefied but vaporizable solvent such as propane or butane is injected at a rate controlled to provide a practical concentration of solvent in the produced fluids (2-50% by weight).
An important advantage of the process is that the tendency for the vaporized solvent to rise will cause the swept region to increase in size upwards.
The solvent is recovered from the produced oil and recycled to the injectors. It is believed that significant increase in recovery from horizontal well projects in areas such as Lloydminster, Alberta, Canada, can be achieved by use of this invention.
There is thus provided in accordance with one aspect of the invention, a method for the recovery of hydrocarbons from an underground reservoir of hydrocarbons, the method comprising the steps of:
injecting a displacement gas and a liquid vaporizable hydrocarbon solvent into an injection well lying in the underground reservoir to mobilize hydrocarbons in the underground reservoir; and PA1 producing mobilized hydrocarbons together with displacement gas and liquid vaporizable hydrocarbon solvent from a production well lying in the underground reservoir spaced from the injection well. PA1 a source of liquid vaporizable hydrocarbon solvent; PA1 a source of displacement gas; PA1 a first injection well drilled horizontally into the reservoir, the injection well having a portion open to fluid communication with the reservoir and being connected to the source of liquid vaporizable hydrocarbon solvent; and PA1 a first production well drilled horizontally into the reservoir, and spaced from the injection well, the first production well including a pump for pumping oil from the well. PA1 drilling a second horizontal well into the reservoir of hydrocarbons spaced from the first horizontal well; PA1 establishing a communication path with flow of displacement gas from the first horizontal well to the second horizontal well; PA1 injecting a hydrocarbon solvent into the reservoir of hydrocarbons through the first horizontal well while injecting displacement gas such that hydrocarbon solvent in the vapor state is present in the displacement gas in the reservoir; and PA1 producing hydrocarbons and displacement gas from the second horizontal well.
In another aspect of the invention, the displacement gas is injected into the injection well until a communication path is established between the injection well and the production well and then the liquid vaporizable hydrocarbon solvent is injected along with the displacement gas.
Preferably, the mobilized hydrocarbons are produced along a predominantly horizontal production well in the underground reservoir.
In another aspect of the invention, where the reservoir has previously been produced by an existing horizontal production well lying at the top of the underground reservoir, the displacement gas is injected into the existing production wells, and in addition, production wells are created by drilling a new production well into the underground reservoir below the existing production well.
Methane and nitrogen are preferred for the displacement gas while butane and propane are preferred for the liquid vaporizable hydrocarbon solvent.
In a further aspect of the invention, there is provided apparatus for the recovery of hydrocarbons from a reservoir of hydrocarbons, the apparatus comprising:
A solvent stripper is preferably connected between the first injection well and the first production well.
In another aspect of the invention, a method is provided for the production of hydrocarbons from a reservoir of hydrocarbons having a first horizontal well drilled into the reservoir of hydrocarbons, the method comprising the steps of:
The hydrocarbon solvent is preferably injected in the liquid phase and vapor from the hydrocarbon solvent preferably saturates the displacement gas. The hydrocarbon solvent is preferably selected from the group consisting of propane and butane.
Further aspects and advantages of the invention are described in the detailed description that follows and set out in the claims that follow.

Process and apparatus for the recovery of hydrocarbons from a reservoir of hydrocarbons


A down-the-hole hammer drill bit retaining assembly is arranged to releasably retain a drill bit at a hammer arrangement of a percussion drilling apparatus. The retaining assembly includes a drive sub and a retainer ring. The drive sub has at least one indent to provide a fluid communication pathway for a flushing fluid extending over a radially outward facing surface of the retainer ring and into an internal region of the drive sub in contact with inwardly projecting splines.

The technique of down-the-hole (DTH) percussive hammer drilling involves the supply of a pressurised fluid via a drill string to a drill bit located at the bottom of a bore hole. The fluid acts to both drive the hammer drilling action and to flush rearwardly dust and fines resultant from the cutting action, rearwardly through the bore hole so as to optimise forward cutting.
Typically, the drill assembly comprises a casing extending between a top sub and a drill bit that, in turn, is releasably coupled to a drive component (commonly referred to as a chuck or drive sub). Drilling is achieved via a combination of rotation and axial translation of the drill bit. Rotation is imparted to the drill bit from the drive sub via intermediate engaging splines. The axial percussive action of the bit is achieved via a piston that is capable of shuttling axially between the top sub and the drill bit and is driven by the pressurised fluid to strike a rearward anvil end of the bit. In some embodiments, a foot valve extends axially rearward from the drill bit to mate with the piston during its forwardmost stroke to control both the return stroke and provide exhaust of the pressurised fluid from the drill head that acts to flush rearwardly the material cut from the bore face. Example DTH hammer drills are described in WO 2008/051132, WO 2013/104470 and U.S. Pat. No. 6,131,672.
Conventionally, the drill bit is retained at the assembly and in contact with the drive sub via a retainer ring. The retainer ring extends around a rearward end of the drill bit shaft and is configured to abut a radially projecting shoulder positioned at the axial rearward end of the bit shaft. Such a configuration prevents the drill bit from falling out of the hammer assembly during flushing or when the hammer assembly (and the drill bit) are loaded into or extracted from the borehole. Example retainer ring assemblies are described in U.S. Pat. No. 5,803,192; US 2007/0089908; EP 1462604 and WO 2001/21930.
However, these conventional retaining assemblies are disadvantageous for a number of reasons. In particular, in an attempt to minimise wear at the drive sub splines, a portion of the pressurised fluid delivered to the drill bit is diverted to the radially outer region of the bit and into contact with drive sub splines. Typically this diverted fluid flow passes between the radially inner surface of the retainer ring and the outer surface of the drill bit shaft. Accordingly, conventional retainer rings include flow path channels or otherwise have a structure to allow the lubricating fluid to reach the axially forward drive sub splines. However, these airflow passageways at the radially inner region of the retainer ring reduce the area contact of the ring with the abutment shoulder of the drill bit. Accordingly, conventional bit retainers are weakened and drill bit retention is compromised. Accordingly, what is required is a drill bit retaining assembly that addresses the above problems and in particular allows delivery of a desired volume of lubricating fluid to the splines whilst providing a secure and reliable retention of the drill bit.

Down-the-hole hammer drill bit retaining assembly


A wedge lock clamping assembly, system and method wherein the module to be clamped in a slot in a chassis has a pair of wedge surfaces oppositely inclined to spaced-apart side surfaces of the slot. The clamping assembly comprises a pair of wedge elements on opposite sides of a movement axis and each wedge element is configured to be disposed within the slot between a respective wedge surface of the module and a respective side surface of the slot. An actuator operates to forcibly urge the wedge elements along the movement axis for causing the wedge elements to be wedged between the respective wedge surfaces of the module and respective side surfaces of the slot for clamping the module in the slot. A toggle is interposed between the wedge elements and the actuator for equalizing the force acting on each wedge element such that the wedge elements will move axially relative to one another to accommodate any difference in gap widths between the wedge surfaces of the module and side surfaces of the slots thereby to minimize any lateral shifting of the module relative to the slot while still securing clamping the module in the slot.

A commonly used electronic packaging process is for electrical "daughter" modules, such as circuit boards or modules, to be plugged perpendicularly into respective connectors on a "motherboard". The term motherboard is often used synonymously with the term backplane to describe a circuit board that contains general circuitry and connectors into which other circuit boards or modules can be plugged. The connectors provide both a physical mount and an electrical interconnect between the daughter boards (modules) and the backplane (motherboard). Usually the backplane is incorporated into a rack (or sub-rack) that may include a chassis or enclosure that surrounds and protects the circuit boards. The chassis may be supplied with guides such as slots and/or pins for guiding the boards into proper position for mating with the connectors on the chassis and further to support the daughter boards with respect to the enclosure or chassis.
Wedge-clamps heretofore have been provided on the edges of the circuit boards or modules as a means to securely hold the edges of the circuit boards in the slots in the chassis. Such wedge-clamps are typically located between one edge of the circuit board and a wall of a slot formed in the chassis. Tightening the wedge clamp forces the board to reference to the chassis slot rather than the (usually underlying) motherboard to which it may be connected. If the slots and motherboard connection are not accurately aligned relative to one another, the board will translate and/or bend and the connector will be stressed, creating a point of possible failure.
The problem is more acute when the circuits are packaged in module form. Typically such modules have a rigid cube-like housing, containing electronics circuitry mounted on one or more circuit boards. The module also has one or more connectors usually located along an edge of the module for electrical connection to a motherboard/backplane. The module includes guides, usually provided on opposite sides of the module, to fit into the slots in the chassis. The guide-slot alignment for locking the guides in place with conventional wedge-clamps requires that the module housing and the chassis slots be formed with relatively precise tolerances to obtain a proper fit and locking action. This increases the cost (in terms of time, labor and expense) of manufacture of such components.


The present invention relates to a wireless network that operates in accordance with the IEEE 802.11n standards and comprises at least one router (2) by which the connections established with the other devices are routed via a wireless network (1), at least one access point (3) which serves as a data transmission point in the network, and at least one client device (4) that uses the network sources; and to a wireless network setup and configuration distribution method (100) which enables to easily configure the devices that connect to the said networks.

Wireless networks whose areas of use increasingly expand nowadays are basically comprised of a router (A) connected to external networks (A) (for example internet), access points between which mutual data transmission is provided via the router, and client devices which are connected to these points via wire or wirelessly. Day by day increase in the number and kinds of client devices brings along the difficulty of identifying these devices to the network.
The existing wireless network products can create a joint network only as a result of making many mutual configurations manually. Additionally, when a configuration related to the network changes in any device, that device remains out of the network. As long as the configuration related to the network does not match with all of the devices the device can not be included in the network. Creating a secure wireless network in which a plurality of devices are involved and subsequently making configuration changes require too much technical knowledge for an ordinary user. Wireless network connections of the mesh networks, which are used to expand the coverage area of wireless networks, other computers that connect to these networks wirelessly and various wireless multimedia devices should be secure, easy-to-setup and the configurations thereof should be easy-to-change.
In WPS (Wi-Fi Protected Setup) definition defined by Wi-Fi Alliance, a method is described that will connect the access point and the wireless device to each other easily and safely. In this definition, expansion of the coverage area by adding new access points between the secondary areas of use are disclosed, while technical details are not specified. This definition does not provide a direct statement for setup and configuration of mesh networks, however it provides an infrastructure suitable for developing specific applications.
In U.S. Patent Application Publication No. US2003087629A1, known in the state of the art, an additional gateway server is proposed as the control mechanism with the purpose of overcoming the flaws of WEP encryption having low level of security and administering a large-scale wireless network. However this application is not a network setup method that can be used by ordinary home users, but it is a wireless network administration application that requires complicated configurations and setups.
In U.S. Patent Application Publication No. US20060285514A1, known in the state of the art, it is proposed to incorporate wireless network feature to devices that are distant from each other such as computer, pocket computer, printer, server and to remote control them. It is provided that wireless network infrastructure should be already setup for this application to operate. However, setup of a mesh network structure that provides wide coverage is also an application that requires technical knowledge in practice.

Wireless network setup and configuration distribution system

AirTies Kablosuz Iletisim Sanayi ve Dis Ticaret AS


A method of preparing an electrode for use in a biophotovoltaic device, comprising the steps of: coating a self-assembled film on a substrate using Langmuir-Blodgett technique; and immersing the coated substrate into an microalgae culture, followed by incubating thereof to grow microalgae thereon hence obtaining a biofilm, characterised in that the self-assembled film is derived from graphene.

Biological photovoltaics (BPV) is an energy-generating technology which uses oxygenic photoautotrophic organisms, or fractions thereof, to harvest light energy and produce electrical power. In contrast to microbial fuel cells which generate electricity from the metabolic process of living microbes, biophotovoltaics produce electricity from light energy via light harvesting apparatus of photosynthetic organisms.
Algae are amongst the most efficient photosynthetic organisms with fast growth rates and tolerance in extreme environments. Nishio et al. (2010) proposed that it is likely that green algae and heterotrophic bacteria grew in the anode biofilm and formed layered structure. It was suggested that green algae and cyanobacteria cooperatively converted light energy into electricity.
Further, McCormick et al. (2011) disclosed a mediatorless biophotovoltaic system by virtue of using bacterial species capable of self-mediated extracellular electron transfer. Particularly, green algae or cyanobacteria strains were grown directly on an indium tin oxide-polyethylene terephthalate (ITO-PET) on anode in a sandwich type or an open air design BPV system. Besides, Ng et. al (2013) disclosed suitable strains of algae capable of forming biofilm on ITO and glass anode in a BPV device for electric power generation. Photosynthetic efficiency of the biofilms were determined.
It appears that anode material is crucial in determining power outputs in a BPV system. In this aspect, Bombelli P. et al. (2012) disclosed their study relating to surface morphology and surface energy of anode material including ITO-PET, stainless steel, glass coated with a conductive polymer and carbon paper. Apart from choosing a suitable anode material, method of treating anode for better adherence of biofilm derived from green algae or cyanobacteria was crucial in enhancing efficiency and power output of a BPV system. The abovementioned thin film or slides of ITO are usually formed via physical vapour deposition on solid surfaces. Particularly, they can be obtained by electron beam evaporation or sputter deposition technique. As such techniques are required to be conducted under vacuum condition, the production of the ITO thin film or slides requires skilled workmanship and specialized facilities hence lead to high production cost.
As an alternative, carbon-based films, such as films of graphene are highly sought-after due to its transparency and relatively lower electrical resistance properties comparing to ITO. The present invention provide method of preparing electrode with such a carbon-based biofilm and BPV device thereof.

Method of fabricating graphene-based/algal biofilm electrode for application in a biophotovoltaic device


A hierarchical sparse tensor compression method based on artificial intelligence devices, in DRAM, not only saves the storage space of the neuron surface, but also adds a meta-surface to the mask block. When reading data, the mask is first read, then the size of the non-zero data is calculated, and only these non-zero data are read to save DRAM bandwidth. In the cache, only non-zero data is stored, so the required storage space is reduced. When processing data, only non-zero data is used. The method uses a bit mask to determine if the data is zero. There are three levels in the hierarchical compression scheme: tiles, lines, and points, reading bitmasks and non-zero data from DRAM, and saving bandwidth by not reading zero data. When processing data, if their bit mask is zero, the tile data may be easily removed.

Artificial intelligence (AI) processing has been a popular topic recently, both in terms of computationally and memory intensive, as well as high performance-power efficiency. Accelerating computing with current devices such as CPUs and GPUs is not easy, and many solutions such as GPU+TensorCore, tensor processing unit (TPU), central processing unit (CPU)+field programmable gate array (FPGA), and AI application-specific integrated circuit (ASIC) have been proposed to address these problems. GPU+TensorCore tends to focus on solving computationally intensive problems, while TPU tends to focus on computation and data reuse, and CPU+FPGA/AI ASICs focus on improving performance-power efficiency.
In artificial intelligence processing, many data are zero due to neuron activation and weight pruning. In order to use these sparsity, it is necessary to propose a compression method that achieve one or more of the following benefits: may save computation, may save power consumption while skipping zero neurons or convolution weights, may reduce the required buffer storage space, and may increase DRAM bandwidth by not transmitting zero data.
Although there are many similar solutions currently, they only use a single layer compression scheme, and this does not have obvious advantages. With a bit mask of two or more layers, if the advanced mask is 0, we can easily remove high-level data, which means that all of the branches are zero, but the traditional single-layer mask Compression cannot get this result.

Hierarchical sparse tensor compression method in artificial intelligent devices

Nanjing Iluvatar CoreX Technology Co., Ltd.


A first device may provide, periodically throughout a test session and to neighboring devices that are in a network with the first device, a message request for measuring network performance. The neighboring devices, upon receiving the request message, are to use a relay mechanism to determine network performance indicator (NPI) values. The first device may receive, from the neighboring devices and periodically throughout the test session, a response message that includes the NPI values. The first device may determine additional NPI values that measure the network performance between the first device and the neighboring devices. The first device may determine overall NPI values based on the NPI values and the additional NPI values. The first device may identify a preferred next-hop to one of the neighboring devices based on the overall NPI values, where the preferred next-hop is part of a preferred path through the network.

A measurement protocol may be used to measure network performance of a group of network devices. For example, a two-way active measurement protocol (TWAMP) may define a standard used to measure network performance between any two network devices that support TWAMP. As such, the group of network devices may use a test session to send probe packets between network devices to measure the network performance.

Network performance monitoring using an active measurement protocol and relay mechanism


A module is disclosed for use as a membrane device, comprising, a shell with fluid couplings removably affixed to each of its ends and at least one non-disassemblable cartridge operably held within the shell. The cartridge is constructed from plural wafers sequentially coaxially aligned, each wafer consisting essentially of a generally planar frame and an array of hollow fibers of selectively permeable material adhesively held by their ends in opposed portions of the border of the frame, without potting the ends. Several cartridges may be coaxially "ganged" to provide the required filtration area. The cartridges may be removably disposed in the shell, or secured therein so that the entire module may be discarded when its efficiency is unacceptably low. The wafers are adhesively secured to define a fluid-tight conduit with open ends through which a feedstream is flowed transversely over the fibers. The bores of the fibers are in open fluid communication with the permeate zone in the shell. A frame of a wafer may be provided with longitudinal, laterally spaced apart grooves in its upper surface and the fibers trained in the grooves. A cartridge may be made by precoating a first frame with adhesive, embedding the fibers in the adhesive, initially curing the adhesive and then placing a second frame over the partially cured adhesive; and, repeating the steps. Alternatively, the second frame may be positioned over the embedded fibers on the first frame and the adhesive then cured. The arrays lie in a plane substantially orthogonal to the direction of flow of a feedstream to be treated, and fibers of one array are staggered relative to those in a successive array.

Though numerous embodiments of framed hollow fiber membranes (referred to as "fibers" for brevity) have been disclosed in this art, and much effort has been expended to provide a "wafer" or "cell" which can be assembled to form a module, the effort has not resulted in a cost-effective module which is reliable, rugged and has wide commercial applications. Prior art cells have sacrificed good exposure of the fibers for packing density by making wafers with bundles of fibers which are in contact with one another to a greater or lesser degree in some wafers compared to others; and, have made wafers with fluid passages in the sides of their frames.
This invention is specifically directed to a cartridge formed by repetitively adding repeating units, each unit consisting essentially of a unitary frame of arbitrary shape and an array of fibers; and, to a module containing a stack of cartridges. The term "repeating unit" is used because such a unit, per se, is difficult to handle and has little practical utility. Such a repeating unit is referred to as a "unitary wafer" to provide better visualization of the physical form of a repeating unit. We know of no prior art cartridge which has been constructed with such "unitary wafers".
A cartridge of unitary wafers was never successfully constructed prior to this time for a number of inter-related reasons, one of which was the high risk of not making a leak-proof cartridge; another was a preoccupation with the ability to replace a defective cell when necessary. Not the least of reasons was that it was not evident how a reliable and economical cartridge could be constructed with simplicity. Moreover, there is no intimation in the prior art of the far-reaching benefits of constructing a cartridge directly, without first constructing a single cell.
Conceptually, the effort in the art has been directed towards providing a single cell, then coaxially assembling plural cells, because it was logical to construct a single cell. A single cell can be handled and checked before being assembled in a module. But a different approach, namely, a concept directed to constructing a reliable and rugged cartridge without making individual cells, led to a solution of the problems in the prior art, namely providing a module with high efficiency and reliability at an affordable cost.
For example, Nichols in U.S. Pat. No. 4,959,152, states "Hollow fiber membranes may be conveniently mounted in annular or similar frames or retainers having a continuous perimeter and an open central portion. The fibers are strung across the open central portion of the frame and the ends are embedded in the retainer thereby forming a wafer. The ends of the fibers are exposed at the outside surface of the retainer, giving access to the interior of the fibers, while the outside surfaces of the fibers are accessible in the open central portion of the retainer." (see col 1, lines 57-66). Soon thereafter he states "Tight sealing of adjacent wafers is essential to avoid contamination of retentate and permeate." Though not explicitly stated, Nichols recognized the importance of sealing plural layers of fibers in each wafer effectively, because he constructed a device to centrifuge an epoxy resin of appropriately chosen viscosity and quick-setting characteristics, to generate a potting ring through which the ends of the fibers protrude to discharge fluid flowing through the lumens of the fibers.
The effectiveness of the centrifugal force however was not restricted to ejecting the epoxy resin radially outward to be deposited against the inner periphery of his mold; the centrifugal force also displaced the fibers in each layer resulting in uncontrolled spacing of fibers and "gaps" which invite channeling. To counter such displacement, individual fibers running parallel to each other in the weft direction in each layer, were woven together ("tied") with warp filaments to form a flat sheet; or, each layer of fibers was adhesively secured to a contiguous layer with a suitable adhesive-coated filament placed on the upper and lower surfaces, respectively, or both, of each layer (see col 4, lines 56-66). Tying fibers together results in chafing at the "ties" and premature rupture of the chafed fiber; and, in entrapment of solids in a "cage" formed by an axial zone between tied fibers.
By "axial" we refer to the central axis of a module, along which axis a multiplicity of arrays of fibers are assembled. For convenience and ease of reference in most of the drawings, the central axis is referred to as being in the vertical direction unless otherwise stated. The arrays of fibers are referred to as being in the lateral plane, one axis of which is referred to as horizontal, and a direction at an angle to the horizontal in the lateral plane is referred to as being transverse.
Our goal was to construct an assembly of coaxially aligned wafers in fluid-tight relationship near the peripheries of their frames, each wafer carrying but a single row ("monolayer") of parallel spaced apart fibers without tying them together or interconnecting them, or potting their ends. Yet we wished to secure the monolayer of fibers in fluid-tight spaced-apart relationship near their terminal portions, in opposed sides (or opposed portions of the border) of a frame having a central or off-set through-passage ("feed channel") for carrying a feedstream to be treated. The problem of confining those terminal portions had little in common with the problem so recently solved by Nichols, namely of securing multiple layers by forming inner and outer potting rings of centrifuged resin, and removing the outer one.
More than a score of years earlier, Strand in U.S. Pat. No. 3,342,729 had to use a mesh of fibers which he sandwiched between two extruded or cast frame members, formed from a suitable thermoplastic polymeric material. The reason he was forced to use a mesh was because such a configuration of meshed fibers had inherent stability. A multiplicity of individual, loose fibers do not have such stability. The stability afforded by the mesh is sufficient to allow the fibers (as a mesh) to be handled and positioned between the frame members. Strand did not suggest positioning individual fibers, in side-by-side relationship between the frame members nor could he have done so without envisioning the possibility of providing an essentially planar array of individual spaced-apart fibers between frame members. The fibers as a mesh, sandwiched between two frame members, is referred to as a "cell" in Strand's invention.
Strand suggested making a cell as follows: "A mesh membrane can be sandwiched between two such (frame) members and the assembly subjected to heat sealing conditions whereby a unitary, integral cell member is provided. This means has the added feature of readily and securely bonding the members into an intimate joined relationship, but additionally avoids the need for any adhesive and sealant material and the attendant setting or drying time. Means can also be provided simultaneously to heat-seal the ends of any fibers protruding beyond the outer edge of the joinder of the two frames by causing the material of the frame to flow over the joinder forming a smooth surfaced seamless edge. Care must be exercised that the hollow fibers are not materially altered in any portion where flow therethrough is desired. The frames can be made in pairs with mating male and female fittings such as lugs and indents to facilitate and assure alignment of the various matching openings. Rapid production of the cells can be achieved by the foregoing means." (see col 7, lines 12-30).
Strand's only description of the fabrication technique he used to form a cell, required a laminated frame constructed from two laminar portions, each having congruent elongated through-passages in each side. The upper surfaces of first laminar portions and the lower surfaces of second laminar portions within the periphery defined by the through-passages in the sides, are coated with adhesive such as an epoxy resin, and the mesh (which is cut slightly larger than the frame) is sandwiched in the adhesive between the upper and lower laminar portions until the mesh is securely and permanently bound to, and held between the laminar portions.
As did others before and after Strand, he suggested a "great number of membrane cells be stacked one above another with very small separations between them (and in some instances one upon another) to develop an extremely large transfer area . . . " (see col 4, lines 25-28). The function of the through-passages, or elongated perforations, in the sides of the frame was to provide multiple flow-channels for permeate, that is, the sides were "functionally perforate". In operation, channels for permeate must be sealed in fluid-tight relationship with the central through-passage ("feed channel") of the frame. Therefore, it was essential that there be no leakage of fluid through openings or channels in a "sealed zone" of any frame. The sealed zone of a frame is defined in the '729 patent as the annular zone adjacent a conduit formed by axially aligned multiple through-passages in an assembly of frames. The sealed zone includes (i) intra-frame space between a fiber and the frame in which it is held, as well as (ii) inter-frame space between successive frame members. The intra-frame space between the outer wall of the fiber and the frame (in which it is held) is sealed by filling it with adhesive which sets over the fibers. The inter-frame space in Strand's module may be sealed with a gasket member, particularly if the assembly, referred to herein as a "stack" of frames, is to be disassembled. The inter-frame space may be sealed with adhesive to non-displaceably secure each frame to a successive frame when there is no intention to disassemble the frames.
The problem we addressed was quite different from the one addressed by Strand. We sought to form a "cartridge" which could be "ganged" with other cartridges to form a "stack" in a module, using appropriate gasket means for disassembly of the cartridges, if desired. Preferably, neither the fibers in each array, nor those of adjacent arrays were to be touching when a cartridge was assembled, and their spaced-apart relationship was to be maintained, except during operation under near-extreme conditions, by essentially only the thickness of the frames in which the fibers were held. Each wafer was to consist essentially of an array of substantially coplanar, non-displaceable, individual, essentially linear fibers, supported in a preferably substantially coplanar unitary laminar frame having a continuous periphery (that is, no separation of the frame). There were to be no flow channels in the sides of the frame, that is, each frame was to be "functionally imperforate". Such perforations as might be provided within the borders of a frame would be solely to position or mount the frame within a shell of a module.
We sought to avoid tying fibers to one another intermediate their terminal portions, either to adjacent fibers in a specific array, or to adjacent fibers in an array above or below the specific array. Fibers in contact with each other not only decrease the effective area of a module of multiple wafers, but exhibit a proclivity to chafe against each other, thus damaging the walls of contacting fibers. Still further, we sought to avoid potting the ends of the fibers, and machining one centrifuged (outer) layer of resin in which the ends of the fibers are plugged, to expose another centrifuged (inner) layer of resin in which the ends of the fibers are not plugged, as in the Nichols' cell.
The significance and importance of securing loose, individual linear fibers in an array of coplanar fibers having generally parallel longitudinal axes, is better appreciated by referring to numerous prior art cells in which fibers are looped about a frame before their ends are secured by potting them. Even before Strand's invention teaching opposed headers in the periphery of each cell, Lewis et al in U.S. Pat. No. 3,198,335 taught a cell in which fibers were also secured in a "header" of the cell, in loops or "hanks", rather than individually, and at least one end of each loop was secured by being potted in resin to form the header. (see col 6, lines 16-30). The desirability of using loops in a cell construction having a header built into the cell was reiterated and refurbished twenty years later in an improvement by Ostertag in U.S. Pat. No. 4,440,641. In the construction of such cells, the fibers must be looped because there is no other means for holding them in place before they are potted. In the wafer we sought to construct we sought to provide no header, the open ends of fibers being so disposed as to communicate with an annular space outside the wafer.
In addition to coping with the problem of positioning a large number of fibers precisely before they are potted, there are numerous pitfalls in "potting" the terminal portions of fibers in a fluid resin which is to be solidified. To begin with, one must find a resin which is sufficiently compatible with the fibers as to form a fluid-tight bond which will survive over the useful life of the module. After having found such a resin one must make sure that movement of the fibers near the resin does not damage the fibers due to the shearing action of the solid resin on their terminal portions, particularly if the pressure differential to be used in the module is substantial. Further, cutting and dressing the solid resin to expose the ends of the fibers may result in plugging many of the fibers, and is to be avoided.
As if these problems were not enough, one must cope with the geometry of the frame which is to support each array of fibers, whatever the configuration of the array, in any assembly of arrays to be housed in a module.
Since we decided to forego potting the fibers we had to find a fast and effective technique for securing the terminal portions of the fibers. This required development of a technique for securing the terminal portions upon or within the border of the frame in such a manner as both, to position the fibers before they are bonded to the frame, and also to provide adequate support at the terminal portions so as to maintain the fibers in spaced-apart relationship relative to other fibers in the assembly.
The development of this technique resulted in the ability to make a cartridge of wafers in which all frame members are permanently sealed, successively, one to another.
In a "cartridge" which is constructed by sequentially assembling frames and monolayer arrays, the number of arrays "n" held between successive frames is one less than the number of frames in which the fibers are held, since a cartridge must begin and end with a frame, that is, there are "n +1" frames; and n represents an integer 2 or greater, preferably in the range from 6 to 100.
It will be appreciated that, though the description of the invention herein is for "outside-in" flow of feed, the module containing a cartridge, or a stack of cartridges, may be equally well adapted for "inside-out" flow, for process considerations demanding such flow. By "outside-in" flow we refer to a feed flowing through the central feed channel in a cartridge or stack, so as to allow a portion of the feed to be separated as permeate. The portion separated as permeate flows from outside the walls of the membranes into their lumens. "Inside-out" flow is when the feed flows through the lumens of the fibers and the permeate is collected outside the membranes.
The cartridge, a module containing the cartridge or stack of cartridges, the method of constructing the cartridge, and the effectiveness of each of the foregoing in a variety of permeation processes, address the deficiencies of the prior art.

Cartridge of hollow fiber membrane wafers and module containing stacked cartridges


A sensing element is formed on a silicon (Si) substrate and covered with a cap. The cap has a leg portion having a titanium layer and a gold layer formed in that order on the lower surface thereof. The silicon substrate has an Si bonding frame at a position corresponding to the leg portion. When bonding the Si bonding frame of the silicon substrate and the leg portion of the cap, the titanium layer deoxidizes a naturally oxidized silicon layer formed on the Si bonding frame, whereby the silicon substrate and the cap can be uniformly bonded together with an Au/Si eutectic portion interposed therebetween. In this case, the Au/Si eutectic portion includes a titanium oxide accompanying the deoxidization of the naturally oxidized silicon layer.

This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 8-264642 filed on Oct. 4, 1996, the contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a semiconductor device including an eutectic bonding portion and a method for manufacturing the same. For example, the present invention is favorably applied to a semiconductor device having a protection cap for covering a functional element therein.
2. Description of Related Art
Conventionally, a semiconductor acceleration sensor, a yaw rate sensor, or the like generally has a movable portion (vibrating portion) on its silicon chip. The movable portion is displaced in accordance with a physical quantity such as an acceleration, and an electric signal corresponding to the physical quantity is determined by converting the displacement of the movable portion to the electric signal. Also, in such a semiconductor device, as disclosed in JP-A-5-326702, a cap covers the movable portion in order to protect the movable portion. In this case, to improve the measurement sensitivity, stability of characteristics, avoidance of air damping, etc., it is preferable that an atmosphere around the movable portions is an inert gas atmosphere, a deoxidation gas atmosphere, or a vacuum atmosphere in some cases. Because of this, there is a need to seal the movable portion in the above-mentioned atmosphere, and therefore a cap for covering the movable portion without causing leakage therefrom is required.
To comply with this need, JP-A-5-326702 discloses a cap for covering not only an element having a movable portion but a chip carrying the element. However, this structure is not suitable for a device having a size which is to be miniaturized. Further, JP-A-4-304679 proposes a technology in which an element is sealed by a thin film formed during a wafer process. In this case, because the thin film serves as a cap, several disadvantages arise such that the mechanical strength thereof is low, the shape of the element is limited, there is no flexibility, and the like. To improve the mechanical strength thereof, a cap made of a bulk can be disposed on the chip in place of the cap made of a thin film. In this case, however, there is a need to invent a bonding method considering a quantity production property.
As a bonding method, anode bonding, direct bonding, and eutectic bonding methods are well known. In the anode bonding method, a high voltage is applied to the chip. If the chip has a circuit element, a withstand voltage of which is not so high, the circuit element is liable to be broken. To avoid this problem, the circuit element may be disposed on another chip other than the chip to which the cap is bonded. That is, the anode bonding method cannot be applied to the chip having the circuit element, and therefore there is no flexibility. In addition, gas is liable to be generated in the anode bonding process thereby adversely affecting sensing properties. Especially, in a vacuum sealing structure, the gas deteriorates the degree of vacuum. In the direct bonding method, there is a necessity to obtain adhesion at an atomic level. Therefore, this bonding method is generally applied to very limited cases. Further, this bonding method requires flat surfaces to be bonded and the application of high pressure. In view of the above, the direct bonding method is also difficult to be applied for the cap to be bonded to the chip.
In the eutectic bonding method that is a long-employed bonding method, the bonding portion is liquidized so that it does not require high pressure applied thereto.
Specifically, in a case where gold (Au) and silicon (Si) is bonded to each other in the eutectic bonding method (Au/Si eutectic bonding method), its bonding temperature is comparatively low and there is consistency between the bonding method and the other processes. Therefore, the eutectic bonding method is considered to be the most effective method for the bonding of the cap.
However, this bonding method has a disadvantage of being liable to produce voids in the bonding portion which may cause leakage therefrom. Now, there is no report about a technique that a void-less bonding is realized with a high yield in the eutectic bonding method. In addition, in the Au/Si eutectic bonding method, because silicon is an extremely active material, a naturally oxidized layer is formed on the surface of silicon. This oxidized layer disturbs an eutectic region to be formed on an entire interface between silicon and gold layers thereby resulting in large variations in bonding strength.
In view of the above-mentioned problems, an object of the present invention is to provide a semiconductor device including a Au/Si eutectic bonding portion which can solve the problems caused by a naturally oxidized layer of silicon and a method for manufacturing the same.
A semiconductor device according to the present invention includes first and second substrates bonded together by an eutectic portion of silicon and gold (Au/Si eutectic portion) containing an oxide of metal that has deoxidized silicon oxide.
In a method for manufacturing a semiconductor device according to the present invention, firstly, a first wafer having a silicon portion on a surface thereof and a second wafer having a gold layer and a metallic layer formed on a surface thereof are prepared. The metallic layer is made of metal having a deoxidizing property relative to silicon oxide. Then, in a state where the first and second wafers contacts each other, the first and second wafers are heated up to a temperature equal to or higher than an Au/Si eutectic temperature, thereby bonding to each other. Then, the first and second wafers are cut into individual semiconductor devices.
During the heating of the first and second wafers, metal of the metallic layer deoxidizes a naturally oxidized layer formed on a surface of the silicon portion of the first wafer. As a result, because the gold layer and the silicon portion can be contacted at an entire interface between the first and second wafers, an Au/Si eutectic portion is formed at all portion between the first and second wafers. Accordingly, variations of bonding strength between the first and second wafers are reduced, so that uniform and stable bonding can be realized. The metallic layer may be made of one material selected from titanium, aluminum, tantalum, zirconium, and niobium. The thickness of the metallic layer is preferably in a range of 10 nm to 100 nm. A protection layer made of gold may be formed on the metallic layer to prevent oxidization of the metallic layer. However, if the heating of the first and second wafers is performed in an atmosphere of vacuum, an inert gas, or deoxidization agent, the oxidization of the metallic layer can be prevented. In such a case, there is no need to form the protection layer on the metallic layer. To promote an eutectic reaction during the heating of the first and second wafers, it is effective to roughen a surface of the silicon portion in advance of the bonding of the first and second wafers.

Semiconductor device including eutectic bonding portion and method for manufacturing the same