A conical bearing apparatus having a dynamic pressure generating groove on the upper section of a conical bearing in order to increase a fluid pressure generated by the other dynamic pressure generating groove formed on the tapered surface of the conical bearing. As fluid generated by the two dynamic pressure generating grooves is completely used for raising the body of rotation, it is possible to raise the body of rotation in a short time. Accordingly, the friction between an optical polygon support and the upper section of the conical bearing is minimized and an abrasion of the optical polygon support or the conical bearing can be reduced. Furthermore, by reducing the overload of the conical bearing and optical polygon support, the stability in rotating the optical polygon is enhanced.

1. Field of the Invention
The present invention relates to a conical bearing apparatus. More particularly, the present invention relates to a conical bearing apparatus having a dynamic pressure generating groove on the upper section of a conical bearing in order to increase a fluid pressure generated by the other dynamic pressure generating groove formed on the tapered surface of the conical bearing.
2. Description of the Related Art
Recently, as the computer-related industries have developed, driving motors for various kinds of devices, such as an optical polygon driving apparatus of a laser printer, a spindle motor of a hard disk, or a head driving motor of a VCR, are required to have high accuracy and superhigh rotation performance without any trembling or vibration of the axis of the apparatus. In response to the demand to eliminate the trembling and vibration of the axis which degenerates the performance of the devices, driving motors capable of being stably rotated at a high speed have been developed, and moreover, a fluid bearing apparatus which rotates the axis of rotation of the driving motor precisely and speedily has been developed.
The above-described fluid bearing apparatus has dynamic pressure generating grooves which generate the dynamic pressure. Dynamic pressure generating grooves are mainly used as follows: a dynamic pressure generating groove having a spiral shape in a thrust bearing for supporting a thrust load; and a dynamic pressure generating groove having a herringbone shape in a radial bearing for supporting a radial load.
Generally, the conical bearing apparatus, which is used in an optical polygon driving apparatus of a laser printer, includes a conical bearing fixed at one end of the axle of fixation; and a bush formed apart from the conical bearing at a predetermined distance for receiving the conical bearing. Accordingly, the optical polygon support connected to the bush faces the upper section of the cone. Moreover, on the tapered side of the cone, a dynamic pressure generating groove is formed. When the bush which is connected to the optical polygon support starts to rotate, fluid flows into the dynamic pressure generating groove of the cone which is facing the conical groove of the bush, thereby generating a dynamic pressure. This dynamic pressure influences the optical polygon support facing the upper section of the cone, and enables the body of rotation to be risen.
In order to minimize the time when the fluid pressure generated by the dynamic pressure generating groove is more than the weights of the bush, optical polygon and optical polygon support, it is necessary to properly design the number and the area of the dynamic pressure generating grooves. However, in the conventional conical bearing apparatus, forming the dynamic pressure generating groove only on the tapered side of the cone is insufficient.
Accordingly, as it takes a long time for the body of rotation, such as the bush, to rise from the cone, an excessive friction between the conical bearing and the body of rotation is generated, thereby causing instability in rotating the axis.

Conical bearing apparatus having a dynamic pressure generating groove


Biomedical nanocomposite implants having both low-loaded and highly-loaded nanocomposites. A matrix and nanofillers are provided wherein the nanofillers are dispersed in the matrix to form a composite. Nanoscale coated and un-coated fillers are used. Methods for preparing biomedical nanocomposite implants are also illustrated.

1. Field of the Invention
In one aspect, the invention comprises a nanostructured filler, intimately mixed with a matrix to form a nanostructured composite. At least one of the nanostructured filler and the nanostructured composite has a desired material property which differs by at least 20% from the same material property for a micron-scale filler or a micron-scale composite, respectively. The desired material property is selected from the group consisting of refractive index, transparency to light, reflection characteristics, resistivity, permittivity, permeability, coercivity, B-H product, magnetic hysteresis, breakdown voltage, skin depth, curie temperature, dissipation factor, work function, band gap, electromagnetic shielding effectiveness, radiation hardness, chemical reactivity, thermal conductivity, temperature coefficient of an electrical property, voltage coefficient of an electrical property, thermal shock resistance, biocompatibility and wear rate.
The nanostructured filler may comprise one or more elements selected from the s, p, d, and f groups of the periodic table, or it may comprise a compound of one or more such elements with one or more suitable anions, such as aluminum, antimony, boron, bromine, carbon, chlorine, fluorine, germanium, hydrogen, indium, iodine, nickel, nitrogen, oxygen, phosphorus, selenium, silicon, sulfur, or tellurium. The matrix may be a polymer (e.g., poly(methyl methacrylate), poly(vinyl alcohol), polycarbonate, polyalkene, or polyaryl), a ceramic (e.g., zinc oxide, indium-tin oxide, hafnium carbide, or ferrite), or a metal (e.g., copper, tin, zinc, or iron). Loadings of the nanofiller may be as high as 95%, although loadings of 80% or less are preferred. The invention also comprises devices which incorporate the nanofiller (e.g., electrical, magnetic, optical, biomedical, and electrochemical devices).
Another aspect of the invention comprises a method of producing a composite, comprising blending a nanoscale filler with a matrix to form a nanostructured composite. Either the nanostructured filler or the composite itself differs substantially in a desired material property from a micron-scale filler or composite, respectively. The desired material property is selected from the group consisting of refractive index, transparency to light, reflection characteristics, resistivity, permittivity, permeability, coercivity, B-H product, magnetic hysteresis, breakdown voltage, skin depth, curie temperature, dissipation factor, work function, band gap, electromagnetic shielding effectiveness, radiation hardness, chemical reactivity, thermal conductivity, temperature coefficient of an electrical property, voltage coefficient of an electrical property, thermal shock resistance, biocompatibility, and wear rate. The loading of the filler does not exceed 95 volume percent, and loadings of 80 volume percent or less are preferred.
The composite may be formed by mixing a precursor of the matrix material with the nanofiller, and then processing the precursor to form a desired matrix material. For example, the nanofiller may be mixed with a monomer, which is then polymerized to form a polymer matrix composite. In another embodiment, the nanofiller may be mixed with a matrix powder composition and compacted to form a solid composite. In yet another embodiment, the matrix composition may be dissolved in a solvent and mixed with the nanofiller, and then the solvent may be removed to form a solid composite. In still another embodiment, the matrix may be a liquid or have liquid like properties.
Many nanofiller compositions are encompassed within the scope of the invention, including nanofillers comprising one or more elements selected from the group consisting of actinium, aluminum, arsenic, barium, beryllium, bismuth, cadmium, calcium, cerium, cesium, cobalt, copper, dysprosium, erbium, europium, gadolinium, gallium, gold, hafnium, hydrogen, indium, iridium, iron, lanthanum, lithium, magnesium, manganese, mendelevium, mercury, molybdenum, neodymium, neptunium, nickel, niobium, osmium, palladium, platinum, potassium, praseodymium, promethium, protactinium, rhenium, rubidium, scandium, silver, sodium, strontium, tantalum, terbium, thallium, thorium, tin, titanium, tungsten, vanadium, ytterbium, yttrium, zinc, and zirconium.
"Domain size" as that term is used herein, refers to the minimum dimension of a particular material morphology. In the case of powders, the domain size is the grain size. In the case of whiskers and fibers, the domain size is the diameter. In the case of plates and films, the domain size is the thickness.
As used herein, a "nanostructured powder" is one having a domain size of less than 100 nm, or alternatively, having a domain size sufficiently small that a selected material property is substantially different from that of a micron-scale powder, due to size confinement effects (e.g., the property may differ by 20% or more from the analogous property of the micron-scale material). Nanostructured powders often advantageously have sizes as small as 50 nm, 30 nm, or even smaller. Nanostructured powders may also be referred to as "nanopowders" or "nanofillers." A nanostructured composite is a composite comprising a nanostructured phase dispersed in a matrix.
As it is used herein, the term "agglomerated" describes a powder in which at least some individual particles of the powder adhere to neighboring particles, primarily by electrostatic forces, and "aggregated" describes a powder in which at least some individual particles are chemically bonded to neighboring particles.
2. Relevant Background
A very wide variety of pure phase materials such as polymers are now readily available at low cost. However, low cost pure phase materials are somewhat limited in the achievable ranges of a number of properties, including, for example, electrical conductivity, magnetic permeability, dielectric constant, and thermal conductivity. In order to circumvent these limitations, it has become common to form composites, in which a matrix is blended with a filler material with desirable properties. Examples of these types of composites include the carbon black and ferrite mixed polymers that are used in toners, tires, electrical devices, and magnetic tapes.
The number of suitable filler materials for composites is large, but still limited. In particular, difficulties in fabrication of such composites often arise due to issues of interface stability between the filler and the matrix, and because of the difficulty of orienting and homogenizing filler material in the matrix. Some desirable properties of the matrix (e.g., rheology) may also be lost when certain fillers are added, particularly at the high loads required by many applications. The availability of new filler materials, particularly materials with novel properties, would significantly expand the scope of manufacturable composites of this type.

This patent is subject to a terminal disclaimer.


Various embodiments provide for detection of tapping of an optical signal. In one embodiment an optical fiber includes a cladding region and first and second core regions. The first core region has a first core medium having a first mode-dependent loss (MDL) figure of merit. The second core region has a second core medium having a second different MDL figure of merit. Tapping of the optical signal may be determined to occur when the MDL of the first and second optical signals differs by a predetermined threshold value.

Optical communications systems provide data transmission paths that are generally robust to interception of information, e.g. eavesdropping. However, under some circumstances an eavesdropper may tap information from the transmission path, e.g. an optical fiber. Such eavesdropping may be difficult to detect, leaving the intended recipient of the transmission unaware that the confidentiality of the transmission has been compromised.

Optical fibers with varied mode-dependent loss


A flexible electrical receptacle system and method for installation is provided. The system includes at least two support bars affixed parallel to one another between two wall support members. A central bar is positioned between the two support bars and configured to move along a length of the parallel support bars. An electrical receptacle affixed to the central bar and configured to move along a length of the central bar.

During the construction or remodel of homes, office buildings, schools, hospitals and other buildings, electrical boxes are installed to provide electrical power to residents or users of the buildings. Traditionally, a metal or plastic box is installed within a wall to hold electrical cables that provide power via one or more sockets. If a wall is already installed, an electrical box can be installed between wall studs by cutting a hole in the existing wall, placing the electrical box inside the hole, and securing the electrical box to the wall using tabs on the box to clamp to a backside of the wall. In contrast, in a new construction, the electrical box is generally affixed to a wall stud using nails prior to installing the wall.
However, once the wall is installed, moving the electrical box can be difficult and time consuming. Specifically, a large amount of the wall, such as sheetrock, must be removed to access and remove the electrical box from the wall stud, and then reposition the electrical box along the same wall stud or a different stud. Finally, a hole in the wall where the electrical box was originally located, must be patched. Further, cutting a new hole in the wall to reposition the electrical box is not a satisfactory alternative because the originally placed electric box must be moved to patch the hole in the wall made for the original electric box.
Accordingly, an electric box that can be conveniently moved after installation of a wall is needed. Preferably, the moveable electric box reduces an amount of work necessary for the move, including removal of a minimal amount of the installed wall, and provides a secure placement of the electric box

Flexible electrical receptacle system and method for installation thereof


To obtain a polymerization initiator (acid generating agent) having excellent power for initiation of cationic polymerization without containing arsenic or antimony.

Salts of onium or transition metal complex are known in prior art as cationic polymerization initiators for curing cationic polymerizable compounds, such as, epoxy compounds by heat or irradiation with active energy beams, such as, by light and electron beam (refer to Patent Reference 1).
In addition, as these salts of onium or transition metal complex produce acids by heat or irradiation with active energy beams are also referred to as acid generators and used in resists and photosensitive materials (refer to Patent Reference 2).
Incidentally, the cationic polymerization initiators described in these specifications contain BF4−, PF6−, AsF6− and SbF6− as anions, cation polymerization initiation capability differs depending on the species of the anion, improving in the order BF4−<PF6−<AsF6−<SbF6−. However, applications using the cationic polymerization initiators containing AsF6− and SbF6−, which have good polymerization initiation capability, are limited due to the problem of toxicity of As and Sb, such that only SbF6− salts are used in limited applications, such as, stereolithography. Therefore, PF6− salts, which have poor polymerization initiation capability, are generally used; however, for instance, in order to obtain a curing speed that is on the same order as that of SbF6− salts, the addition of nearly 10 times the quantity of the latter is required for PF6− salts, and problems exist, such as, loss of physical properties of the cured material due to the large residual amounts of unreacted initiator, solvent used as necessary to dissolve the initiator or decomposition products from the initiator, furthermore, easy corrosion of substrates, equipments and the like due to large amounts of the byproduct HF from the decomposition of the initiator. Therefore, a cationic polymerization initiator not containing a toxic element, having a cationic polymerization initiation capability that is comparable to that of SbF6− salts, is strongly sought.
Onium salts or salts of transition metal complex having tetrakis (pentafluorophenyl) borate as anion are proposed as cationic polymerization initiators responding to this problem (refer to Patent Reference 3); however, although the polymerization initiation capability thereof with respect to cationic polymerizable compounds is better than that of those having PF6− as anion, it is poorer compared to that of those having SbF6− as anion, such that an still better improvement is desired.
[Patent Reference 1] Japanese Patent Application Laid-Open No. S50-151997, Japanese Patent Application Laid-Open No. S50-158680, Japanese Patent Application Laid-Open No. H2-178303, U.S. Pat. No. 4,069,054, idem 4450360, idem 4576999, idem 4640967, Canadian Patent No. 1274646, European Patent Application Disclosure No. 203829
[Patent Reference 2] Japanese Patent Application Laid-Open Nos. H2002-193925, 2001-354669, 2001-294570
[Patent Reference 3] Japanese Patent Application Laid-Open No. H6-184170

Fluorinated alkyl fluorophoshoric acid salts of onium and transition metal complex

Abstract: Provided is a specific onium salt or transition metal complex salt of a fluorinated alkyl fluorophosphoric acid.


A decoding device having a turbo decoder and an RS decoder concatenated serially and a method of decoding performed by the same. A turbo decoder decodes received data of a channel and an RS decoder RS decodes the turbo decoded data. A controller controls the turbo decoder to iteratively turbo-decode the data according to a number of iterations determined by a stored iteration number and to cease the turbo decoding if an error correction completion signal is received from the RS decoder. The controller decreases the iteration number for a next frame of the data if the completion signal is received within the predetermined number of iterations and increases the iteration number for a next frame if the completion signal is not received within the predetermined number of iterations. The iteration number is changeable within maximum and minimum limits and may exceed the maximum limit in special cases.

1. Field of the Invention
The present invention relates to a decoding device having a turbo decoder and an RS decoder serially concatenated, and more particularly, to a device for decoding a signal which has undergone both an RS encoding and a turbo encoding, and a decoding method thereof.
2. Description of the Related Art
Generally, in order to correct an error on a channel, a wireless digital communication system uses a method of adding an error correction code in a transmitting terminal and a method of correcting the error in a receiving terminal. One of the coding methods used for the error correction is a turbo code. The turbo code is employed for a channel in need of a high data rate such as CDMA2000 used in the USA, and W-CDMA used in Europe.
FIG. 1 is a block diagram of a conventional decoding device for decoding a received turbo code.
A signal received through a channel passes an input buffer 10 and is input into a turbo decoder 20. The turbo decoder 20 decodes a turbo code by an iterative decoding method and the decoded signal is transmitted to an output buffer 70.
The turbo code varies in the error correction capacity according to an iteration number of the iterative decoding operation. As the iteration number gets greater, the possibility of error correction increases. However, if the iteration number is too great, a decoding time becomes long and power consumption for decoding increases. Therefore, a controller 40 ceases the iterative decoding once the error correction is performed beyond a particular level.
Two conventional criteria determining methods of ceasing the iterative decoding are described below.
The first method is to predetermine an iteration number and cease the iterative decoding when the iteration number reaches the predetermined iteration number. However, this method may increase the decoding time and power consumption as the unnecessary iterative decoding may be performed even though an error is sufficiently corrected. Additionally, this method has a problem that the desired error correction performance may not be achieved as the iterative decoding can be ceased although the error correction is not completed.
The second method is to have a separate LLR (Log Likelihood Ratio) calculator or CRC (Cyclic Redundancy Check) generator 30 as shown in FIG. 1. In other words, it is a method that, by performing the CRC on the signal decoded during the iterative turbo decoding or producing the LLR of the decoding results, the decoding is ceased when it is determined that the error correction is completed according to the CRC result or when the minimum value of the absolute values of the LLR is higher than a predetermined threshold value.
However, in the method using the CRC, the turbo code should be encoded again according to the CRC method, which may cause a data rate loss and the CRC result may be incorrect.
In addition, the method using the LLR has a difficulty in determining a proper threshold value for ceasing the iteration, and errors may still occur even though the LLR conditions are met.
The iteration control of the turbo decoder by the method mentioned above can be adopted even if the error correction is done by the turbo decoder alone. Recently, a new error correction method using both a turbo decoder and a Reed Solomon Decoder (RS decoder) is suggested (U.S. Pat. No. 6,298,461) where a decoding result of an RS decoder is used to control the iteration of the turbo decoder to get a better decoding result.

Decoding device having a turbo decoder and an RS decoder concatenated serially and a method of decoding performed by the same


A device for heat treating (annealing) a III-V semiconductor wafer comprises at least one wafer support unit which is dimensioned such that a cover provided above the wafer surface is either spaced without any distance or with a distance of maximally about 2 mm to the wafer surface. A process for heat treating III-V semiconductor wafers having diameters larger than 100 mm and a dislocation density below 1×104 cm−2 is carried out in the device of the invention. SI GaAs wafers produced have an at least 25% increased characteristic fracture strength (Weibull distribution), an improved radial macroscopic and mesoscopic homogeneity and an improved quality of the mechano-chemically polished surface. The characteristic fracture strength is higher than 1900 MPa.

The invention relates to a device and a process for heat treating (also referred to as annealing) of III-V wafers (also called substrates), and to annealed wafers or substrates. The invention particularly relates to the aforementioned device, process and wafer based on GaAs semiconductor materials, above all of semi-isolating (SI) GaAs wafers, as well as GaAs wafers produced according to the VGF (Vertical Gradient Freeze) and the VB (Vertical Bridgman) process. Because the electric, electronic and other physical properties of such annealed wafers are adjustable, they are particularly suited for the manufacture of active microelectronic devices based on III-V semiconductors.
In the crystal growth process from a melt, the solidified material goes through a thermal history dependent of location. That is, the effective maintenance time in a certain temperature range, in which balancing or compensation processes (e.g. relaxation of residual strength, homogenization, etc.) are possible, varies for different parts of a crystal. Therefore, it is common practice to subject single crystals to an equational heat treatment after the termination of the crystal growth process, either in the growth apparatus or preferably in a separate heating furnace. The annealing of GaAs single crystals was first applied by RUMSBY et al. (D. Rumsby, R. M. Wafer, B. Smith, M. Tyjberg, M. R. Brozel, E. J. Foulkes: Tech. Dig. GaAs IC Symp., New York, IEEE, 1983, 34) for strain relaxation and homogenization of electrical properties of non-doped, semi-insulating LEC Liquid Encapsulated Czochralski)-GaAs single crystals. Since then, the crystal annealing processes have been systematically optimized, specifically with respect to the application and the customer; and in addition to homogenization, they also serve for the control of defect sites. An overview of crystal annealing of GaAs is given, inter alia, by ODA et al. (O. Oda, H. Yamamoto, K. Kainosho, T. Imaizumi, H. Okazaki: "Recent developments of bulk III-V materials: annealing and defect control," Inst. Phys. Conf. Ser. No 135, pp 285-293, 1993).
The basic physical mechanism of each heat treatment is the diffusion of intrinsic defect sites and impurities under the consideration of possible factors, such as Fermi level and dislocations, which possess increased diffusibility ("pipe diffusion") and with which point defects may react (segregation). Due to the smallness of the self diffusion coefficients and many extrinsic diffusion coefficients even close to the melting temperature of GaAs, the equational processes affected thereby are limited to mesoscopic linear dimensions (O(100 μm)). In particular, a homogenization of axial and radial concentration inhomogeneities, which are formed by macrosegregation of dopants and impurities during crystal growth, is not possible by crystal annealing.
Specifically, GaAs has a homogeneity region that includes the stoichiometric composition, with a retrograde solubility at least on the As-rich side of the homogeneity region (H. Wenzl, W. A. Oates, K. Mika: "Defect thermodynamics and phase diagrams in compound crystal growth processes," in: D. T. J. Hurle (ed.): Handbook of Crystal Growth, vol. 1A, North-Holland, Amsterdam, 1993). A consequence of the retrograde solubility is the formation of As precipitates when exceeding the solidus line during the cooling procedure, which is coupled with changes in the intrinsic defect inventory of GaAs ("structural point defects"). A distinction is made between matrix precipitates and decoration precipitates having different size distributions, which are formed by homogenous and heterogenous nucleation, respectively. The size distribution of the decoration precipitates (DP) additionally depends on the dislocation density of the material. The lower the dislocation density, the higher the average size of the precipitates. That is, VGF/VB-GaAs, in particular that having SI properties, has larger, greater DP compared to LEC-GaAs. On the other hand, LEC-GaAs, though having a smaller sized DP, has a relatively high dislocation density of substantially above 1×104 cm−2. Dissolving the precipitates by a holding step in the homogeneity region, and re-precipitating the excessive arsenic by means of a defined cooling process thus represents—considering the distribution and the amount of deposited arsenic—a possibility to control not only the defect inventory, but also of the As precipitates by means of crystal annealing. However, heat treating single crystals of large dimensions poses strict limitations on the realizable heating and cooling rates in view of the physico-thermal properties of GaAs, if thermal strain is to lie below certain limits in favor of a constant dislocation density, or for the avoidance of fractures.
During mechano-chemical polishing of the wafers, the As precipitates cause etch pit-like defects in the surface, which are detectable by light scattering techniques as so-called COPs (Crystal Originated Particles) and are classified depending on their size, and which must meet specifications of the use and the user. The size distribution of the COPs depends, inter alia, on the respective polishing procedure; however, it is basically proportional to the size distribution of the As precipitates. That is, on the average, the COPs are larger in VGF/VB-GaAs than in the LEC material. COPs may disturb epitaxial growth and may cause an unacceptable "roughness" of the stacked layers in the manufacture of device elements. Moreover, it is known that the As precipitates affect the circuit behavior of FETs produced by ion implantation (U.S. Pat. No. 5,219,632).
Besides the common practice of carrying out annealing of the whole crystal (ingot), a heat treatment of single wafers, the so-called wafer annealing, is known. There, different from crystal annealing, use can be made of the fact that, with GaAs (and other III-V compounds), arsenic (i.e., the V component) has a higher vapor pressure than gallium (i.e. the III-component) above the temperature of the congruent evaporation. In this manner, it can be tried, at least in principle, to adjust the composition of GaAs in a surface-near region of the wafer by means of an As partial pressure, which is applied from the outside (for example, by evaporating solid arsenic, or by other means) (see O. Oda, H. Yamamoto, K. Kainosho, T. Imaizumi, H. Okazaki: "Recent developments of III-V materials: annealing and defect control," Inst. Phys. Conf. Ser. No 135, pp 285-293, 1993).
Another known variant of wafer annealing is heat treatment after ion implantation. It serves for the activation of implanted dopants, wherein a selective As evaporation is suppressed by an As partial pressure corresponding to the activation temperature, or by a diffusion barrier of Si3N4, AlN or another cover layer.
Starting from a 1-step wafer annealing procedure (U.S. Pat. No. 5,219,632), a 2-step (JP 01-153481 A, U.S. Pat. No. 5,047,370) and finally a 3-step procedure (JP 04-215439 A, U.S. Pat. No. 5,137,847) were developed in the wafer annealing for further improvement of the mesoscopic homogeneity.
These developments have in common that, in a first (in U.S. Pat. No. 5,219,632 the only) annealing step at T>1100° C. and t>30 min in a quartz ampoule, the density of the so-called micro defects of typically 5×105 cm−3 in SI LEC GaAs is decreased to ≦5×103 cm−3 under a not further defined As partial pressure, for the avoidance of a selective As evaporation, and by a subsequent cooling to room temperature at a rate of 1-30 K/min. Micro defects are defined as deposits of impurities or As precipitates that can be detected by the known AB etching as oval etch pits on the wafer surface. Preferably, lapped or purity-etched wafers, optionally also in the as-grown status, are used. After double sided etching of the annealed wafers, the second annealing at 750° C.-1100° C. (preferable at 900° C.-1000° C.) is carried out for at least 20 min. Again, it is annealed in a quartz ampoule, but now in a non-oxidizing atmosphere, such as, e.g., N2, H2, Ar or also AsH3, with a not further specified pressure, i.e., non-conservative without As potential and therefore under extracting conditions, or alternatively in a conservative manner with an As partial pressure for suppressing degradation of the surfaces. The indications on the process gas are therefore contradictory. This manner of operation may, however, be provisionally contemplated, to the extent that the wafers are etched, pre-polished and finally polished after the annealing, so that a possibly changed composition in the region close to the surface is of no importance.
In the publications JP 08-255799 A, JP 08-259396 A and JP 09-194300 A, the second annealing in a T range of 800° C.-1000° C. is carried out under an As partial pressure, which is at least 1.4- to 2-fold of the pressure above stoichiometric GaAs at the respective temperature. Thereby, the stoichiometric imbalance and the EL2 concentration associated therewith are increased in a region near the surface. The publications are silent on the behavior of As precipitates during this heat treatment.
In the 3-step wafer annealing described in U.S. Pat. No. 5,137,847 or JP 04-215439 A, a further annealing is carried out at 520-730° C. under As partial pressure. In this document, the 3-step annealing is indicated as being optimal with respect to homogenization and a decrease of micro defects.
The high cooling rate demanded after the first annealing step is disadvantageous and unacceptable, because it leads with high probability to a multiplication of dislocations (slip line formation) based on too high of a thermal strain. This is consistent with the Japanese laid-open patent application JP 2002-274999 A, which limits the heating and cooling rates to ≦200 K/h or ≦100 K/h, as well as with JP 2001-135590 A, which relates to a certain temperature scheme wherein both the heating and the cooling rates are changed depending on the temperature T. However, it was not noticed that critical heating and cooling rates should be different for the avoidance of a multiplication of dislocations for LEC-GaAs and VGF-GaAs, respectively. Furthermore, the amount of material and labor drastically increases concurrent with the number of annealing steps.
In JP 09-199508 A, it is disclosed to stack the GaAs wafers to be annealed one above another, to press them together via an elastic element under a defined pressure, and to anneal them in this manner under a non-oxidizing atmosphere (N2, Ar, H2, AsH2) in a container in a temperature range between 800-1000° C.
JP 05-082527 A discloses a device for annealing wafers in a vertical arrangement. The device consists of 3 azimutally displaced support rods having cuts at defined intervals for receiving the respective wafer. The support rods are fixed to a cone flange. They are formed in a hollow manner, may receive one or more thermo elements and may be supplied by a cooling gas. This device is inserted into a vertically arranged quartz ampoule having a corresponding cone cutting. The ampoule has an extension at its lower extremity for receiving metallic arsenic. The extension projects into a separate heater, the temperature of which controls the As partial pressure in the ampoule and thereby avoids a degradation of the wafers. The wafers are heated by a furnace having several separate heaters, which are controlled by means of an inner thermal element, such that a constant temperature may be maintained over the whole insert length of the wafers. The ampoule may be evacuated. The ampoule having the wafers inserted therein may be closed through a cone cutting, or may be melt sealed as well.
Instead of one wafer for each level, two backside contacted GaAs wafers may also be inserted according to JP 2000-294561.
According to JP 06-302532 A, and likewise in JP 10-287500 A and JP 10-289883 A, the wafers are laid on supports made of heat resistant materials, such as pBN, graphite, silicon, tungsten, molybdenium, and these supports are stacked vertically or horizontally and are inserted into the annealing ampoule in this matter. In the horizontal storage of the wafers on supports, borings between the wafer supports serve for a better exchange with the process gas (see JP 10-321540 A).
EP 0 399 662 A describes a process for annealing semiconductors of the type A3B5 (III-V) and A2B6 (II-VI), wherein the semiconductor having its surface encapsulated by a glass encapsulation film is subjected to a fast thermal annealing (RTA) in order to anneal defects caused by ion implantation. In a treatment device, a cover 12 is provided above a wafer 1 having a thickness of about 500 μm through a spacer ring 11, which typically has a height of 600 to 900 μm, so that a free space of at least 100 μm is formed for allowing the wafer to expand and for enabling a homogeneous heat transfer to the wafer. The encapsulation film intentionally provides a barrier above the wafer surface, such that no (mass) transport is possible between the semiconductor material of the wafer and the free space.

Device and process for heating III-V wafers, and annealed III-V semiconductor single crystal wafer


The present invention pertains to modified xylanase enzymes that exhibit increased thermostability and alkalophilicity, when compared with their native counterparts. Several modified xylanases exhibiting these properties are disclosed including xylanases with at least one modification at amino acid position 10, 27, 29, 75, 104, 105, 125, 129, 132, 135, 144, 157, 161, 162 or 165, or a combination thereof. Also included within the present invention is a modified xylanase that comprises at least one substituted amino acid residue and that may be characterized as having a maximum effective temperature (MET) between about 69° C. and about 78° C., wherein the modified xylanase is a Family 11 xylanase obtained from a Trichoderma sp. The present invention also includes a modified Family 11 xylanase obtained from a Trichoderma sp. characterized as having a maximum effective pH (MEP) between 5.8 and about 7.6. Modified xylanases characterized as having a MET between about 69° C. and about 78° C. and a MET between about 5.8 and 7.6 are also disclosed.

Xylanases are a group of enzymes with wide commercial utility. A major application of xylanases is for pulp biobleaching in the production of paper. In addition, xylanases have been used as clarifying agents in juices and wines, as enzymatic agents in the washing of precision devices and semiconductors (e.g. U.S. Pat. No. 5,078,802), and they are also used for improving digestibility of poultry and swine feed.
In the manufacturing of pulp for the production of paper, fibrous material is subjected to high temperatures and pressures in the presence of chemicals. This treatment converts the fibers to pulp and is known as pulping. Following pulping, the pulp is bleached. Xylanase enzymes are used to enhance the bleaching of the pulp. The xylanase treatment allows subsequent bleaching chemicals such as chlorine, chlorine dioxide, hydrogen peroxide, or combinations of these chemicals to bleach pulp more efficiently. Pretreatment of pulp with xylanase increases the whiteness and quality of the final paper product and reduces the amount of chlorine-based chemicals which must be used to bleach the pulp. This in turn decreases the chlorinated effluent produced by such processes.
The most important chemical pulping process is kraft pulp. For kraft pulp, following pulping, and prior to the treatment of pulp with xylanase, the pulp is at about a temperature of 55-70° C. and at a highly alkaline pH (e.g. Nissen et al., 1992). A drawback of many commercially available wild-type xylanases, is that these enzymes exhibit an acidic pH optimum and a temperature optimum of about 55° C. Therefore, in order to effectively utilize xylanases for bleaching applications, the pulp must be acidified to a pH approximating the optimal pH for the specific xylanase used. In addition, the hot pulp must be cooled to a temperature close to the optimal temperature for enzymatic activity of the selected xylanase. Decreasing pulp temperatures for xylanase treatment decreases the efficiency of the subsequent chemical bleaching. Acidification of pulp requires the use of large quantities of acids. Further, the addition of acids leads to corrosion, which lessens the lifetime of process equipment. Thus, xylanases optimally active at temperatures and pH conditions approximating the conditions of the pulp would be useful and beneficial in pulp manufacturing.
Xylanases which exhibit greater activity at higher temperatures could be used to treat pulp immediately following the pulping process, without the need to cool the pulp. Similarly, xylanases which exhibit greater activity at higher pH conditions would require less or no acid to neutralize the pulp. The isolation of, or the genetic manipulation of, xylanases with such properties would provide several advantages and substantial economic benefits within a variety of industrial processes.
Several approaches directed towards improving xylanase for use in pulp-bleaching within the prior art include the isolation of thermostable xylanases from extreme thermophiles that grow at 80-100° C., such as Caldocellum saccharolyticum, Thermatoga maritima and Thermatoga sp. Strain FJSS-B.1 (Lüthi et al. 1990; Winterhalter et al. 1995; Simpson et al. 1991). However, these thermostable xylanase enzymes are large, with molecular masses ranging from 35-120 kDa (320-1100 residues), and exhibit a reduced ability to penetrate the pulp mass compared with other smaller xylanases which exhibit better accessibility to pulp fibers. In addition, some of the extremely thermophilic xylanases, such as Caldocellum saccharolyticum xylanase A, exhibit both xylanase and cellulase activities (Lüthi et al. 1990). This additional cellulolytic activity is undesirable for pulp bleaching, due to its detrimental effect on cellulose, the bulk material in paper. Furthermore, hyper-thermostable xylanase enzymes which function normally at extremely high temperatures have low specific activities at temperatures in the range for optimal pulp bleaching (Simpson et al. 1991).
A number of xylanases have been modified by protein engineering to improve their properties for industrial applications. For instance, U.S. Pat. No. 5,759,840 (Sung et al.), and U.S. Pat. No. 5,866,408 (Sung et al.) disclose mutations in the N-terminal region (residues 1-29) of Trichoderma reesei xylanase II (TrX). Three mutations, at residues 10, 27 and 29 of TrX, were found to increase the enzymatic activity of the xylanase enzyme at elevated temperatures and alkaline pH conditions.
U.S. Pat. No. 5,405,769 (Campbell et al.) discloses the modification of Bacillus circulans xylanase (BcX) using site-directed mutagenesis to improve the thermostability of the enzyme. The site specific mutations include replacing two amino acids with Cys residues to create intramolecular disulfide bonds. In addition, specific residues in the N-terminus of the enzyme were mutated which were also found to further improve the thermostability of the enzyme. In in vitro assays, the disulfide mutants showed thermostability at 62° C., an improvement of 7° C. over the native BcX xylanase enzyme. However, these thermostable disulfide mutants showed no gain in thermophilicity in laboratory assays in subsequent studies (Wakarchuck et al., 1994). Mutations T3G (i.e. threonine at position 3 replaced with Gly; BcX xylanase amino acid numbering), D4Y(F) and N8Y(F) near the N-terminus of the BcX xylanase enzyme provided thermostability to 57° C., an increase of 2° C. over the native BcX (U.S. Pat. No. 5,405,769). However, the use of these enzymes within industrial applications still requires cooling and acidification of pulp following pretreatment, prior to enzyme addition. Therefore, further increases in thermostability, thermophilicity and pH optima are still required.
There is a need in the prior art to obtain novel xylanases which exhibit increased enzymatic activity at elevated temperatures and pH conditions, suitable for industrial use. It is an object of the invention to overcome drawbacks in the prior art.
The above object is met by the combination of features of the main claim, the sub-claims disclose further advantageous embodiments of the invention.

Modified xylanases exhibiting increased thermophilicity and alkalophilicity


An exposure control device in a camera comprises a focus detection device for calculating a plurality of defocus amounts corresponding to a plurality of focus detection areas, a weight producing device for producing a plurality of weights corresponding to the plurality of focus detection areas on the basis of the plurality of defocus amounts, a light metering device for light-metering a plurality of light metering areas at least partly overlapping with the plurality of focus detection areas and producing a plurality of light metering outputs, and an exposure amount calculating device for calculating a proper exposure amount on the basis of the plurality of weights and the plurality of light metering outputs.

1. Field of the Invention
This invention relates to an exposure control device in a camera.
2. Related Background Art
There has heretofore been an exposure control device in a camera which effects the distance measurement of a plurality of areas of the object field and carries out exposure calculation by the use of the output of a light metering area corresponding to an area which is in focus.
In such device, however, too much importance is attached to the output of the light metering area corresponding to the area which is in focus and use is not made of the output of a light metering area corresponding to an area which is out of focus, and this has led to the problem that the resultant photograph partly obtains proper exposure, but generally suffers from unbalanced exposure.
This problem is particularly severe in a scene wherein the luminance difference is great.


The invention includes a method and apparatus for determining a routing table for use in a network comprising a plurality of type-one nodes and a plurality of type-two nodes where the type-two nodes use respective type-two routing tables having one next-hop node associated with each of a plurality of destination nodes of the network. The method includes obtaining, from the type-one nodes and the type-two nodes, link status information associated with each of a plurality of links of the network, obtaining traffic measurement information from the type-one nodes and the type-two nodes, and determining, using the link status and traffic measurement information, type-one routing tables for the respective type-one nodes. The type-one routing tables are determined as a group in a substantially coordinated manner, and each type one routing table includes a plurality of next-hop nodes associated with each of the destination nodes.

The scalability and resiliency of connectionless networks is evident from the ubiquity and rapid growth of the Internet. Despite the success of connectionless networks, many service providers use connection-oriented networks for achieving global objectives such as network traffic engineering. This is primarily due to the fact that traffic management in connection oriented networks is operationally simpler than traffic management in connectionless networks. Specifically, service providers often use layer-two connection-oriented networks for achieving global objectives for layer-one connectionless networks. An example is the use of Multi-protocol Label Switching (MPLS) for carrying Internet Protocol (IP) traffic.
In connection-oriented networks, traffic is typically routed from source to destination along pre-determined paths. Since these pre-determined paths may be established and manipulated individually, it is possible to adjust the pre-determined paths to accommodate changing traffic conditions in the network. This accommodation of changing traffic conditions is important for providing a quality of service guarantee for traffic associated with pre-determined paths. Disadvantageously, connection-oriented networks require path establishment for supporting traffic flows originating in the network, making the scaling of connection-oriented networks difficult. Furthermore, failures in the network require explicit establishment of restoration paths, thereby reducing operational ease of connectionless networks.
Use of connection oriented networking, despite ease of deployment and scalability of connectionless networking, is due to the fact that connectionless networks typically use shortest-path, hop-by-hop routing. The use of shortest-path, hop-by-hop routing is well-suited for maintaining best-effort connectivity (e.g., as is done using widely deployed routing protocols such as OSPF), however, maintaining connectivity is not the only objective for service providers. In additional to maintaining connectivity, service providers seek efficient traffic management, effective capacity use (e.g., avoiding congestion on some links while other links remain underutilized), and like objectives. Disadvantageously, while such network-wide objectives are easier to meet with connection-oriented networks than with routing currently employed in connectionless networks, connection-oriented networks are not as scalable as connectionless networks.

Method and apparatus for improved routing in connectionless networks


An electronic device that includes functionality to perform at least two functions, a first of which may be timekeeping and the other of which is at least a function other than the first function. The electronic device comprises a multilayered module comprising a frame having a frame surface; at least two physically separable printed circuit boards, the first of which includes means related to at least the timekeeping and the second of which includes means related to at least the function other than timekeeping, wherein the first printed circuit board is intermediate the frame surface and the second printed circuit board; a battery compartment dimensioned for receiving a battery, wherein the battery compartment is asymmetrically positioned within the module thus creating a region above the first printed circuit board and proximate the battery compartment; and wherein the second printed circuit board is securable within the module and in the region; wherein the functionality of the electronic device can be changed and/or modified by a removal of the second printed circuit board and a replacement with another printed circuit board having means at least in part different from and/or in addition to the means of the second printed circuit board; whereby the first printed circuit board need not be removed to provide for such additional and/or different functionality provided by the replacement printed circuit board.

The present invention is generally directed to the construction of electronic devices, such as timepieces in general and watches in particular, and specifically, to an improved module construction for such electronic devices that allows for increased functional versatility.
Manufacturers of timepieces, as well as manufactures of all electronic devices, continually seek ways to meet the needs of its consumers. One way to do so is by providing such a wide range of products that would be of interest to the consumer.
From an inventory control and a manufacturing perspective, it is always a desire and objective to design such electronic devices with the most amount of common components, thereby decreasing inventory costs while also making the manufacturing process as easy and inexpensive as possible, notwithstanding differences among the products.
In any family of products, such as timepieces in general and watches specifically, there are certain basic features and components that remain the same throughout each of the products, no matter what specific differences each product may have. For example, it would not be uncommon to find certain consistencies across a wide range of products, such as timepiece module size and dimensions, certain circuit board layouts and design, battery requirements and characteristics, dial and gear train constructions and/or LCD displays. Thereafter, with any "basic" module design, all that would need to vary between differing products are those features and components that are needed to provide such functional differences, enhancements and/or modifications.
The assignee of the present invention has recognized that consistency and uniformity, where possible, is important for a number of reasons, not the least of which are inventory control costs, manufacturing capabilities and costs, and brand recognition. The more a timepiece module can remain the same, the more optimized the manufacturing process can become. For example, timepieces with a compass mode, a heart rate monitor, an altimeter function or the like, are all believed to be possible within a common timepiece module. In fact, reference may be had to coowned and copending U.S. application Ser. No. 10/441,417, the subject matter of which is incorporated by reference as if fully set forth herein, which discloses the wide potential of differing products that are available under one common design.
Accordingly, it is desirable to design and construct a timepiece module that provides and allows for increased functional versatility.

Multifunctional timepiece module with application specific printed circuit boards


A semiconductor device includes a laminated substrate having circuit boards, an insulating plate, and a metal plate laminated, and warped convexly to the circuit board side; semiconductor chips fixed to the corresponding circuit boards; a base plate having a predetermined disposition region in which the laminated substrate is disposed, grooves disposed in the outer periphery of the disposition region, and projections disposed in positions in the disposition region adjacent to and inside the grooves. The grooves has on the projection side an inclination corresponding to an inclination caused by the warp of the laminated substrate. A joining material fills the space between the metal plate and the disposition region and covers the grooves and projections.

A main portion of an example of a heretofore known semiconductor device is shown in a sectional view (FIG. 9(a)) and a plan view (FIG. 9(b)).
A semiconductor device 101 shown in FIGS. 9(a) and 9(b) includes a metal base plate 102. The base plate 102 has through holes 102a for mounting the semiconductor device 101 to a heat sink (not shown) with bolts. A laminated substrate 103 is joined to the top of the base plate 102 by a joining material 104. The joining material 104 is specifically a solder. The laminated substrate 103 is formed of an insulating plate 131, a metal plate 132 provided on one surface of the insulating plate 131, and circuit boards 133 which are provided on the other surface of the insulating plate 131 and which form a predetermined circuit. The laminated substrate 103 is, for example, a DCB (Direct Copper Bond) substrate.
Semiconductor chips 105, such as IGBTs (insulated gate bipolar transistors), are electrically and mechanically connected to the circuit board 133 by respective conductive joining materials 106. "Being electrically and mechanically connected" is defined as including not only a case in which objects are connected together by direct joining, but also a case in which objects are connected together via a conductive joining material, such as a solder or a metal sintered material, and the same applies in the following description.
As the base plate 102 and laminated substrate 103 of the heretofore described of semiconductor device 101 are different in heat expansion coefficient from one another, heat stress is applied to the joining material 104 due to the heat generation when the semiconductor chips 105 are in operation. Further, when the semiconductor device 101 is in operation, there is fear that cracks are generated in the joining material 104 by repetition of the heat stress. FIG. 10 shows an ultrasonic observation image, wherein the condition of cracks generated in the joining material is observed. FIG. 10 is an image of the joining material 104 seen from above, wherein the white portions show cracks. As shown in FIG. 10, cracks are generated in an outer periphery, such as at four corners, of the joining material 104, and grow inward. Also, in order to prevent the generation and growth of cracks in the joining material 104, it is effective to form the joining material 104 to a certain thickness.
In order to form the joining material 104 to a certain thickness, projections 121 are disposed on the principal surface of the base plate 102. The distance between the base plate 102 and the metal plate 132 is defined by the projections 121, thus obtaining the joining material 104 with the same thickness as the height of the projections 121.
However, it is not possible to sufficiently secure the thickness of the joining material 104 in the outer peripheral portion of the metal plate 132 in the case of the semiconductor device 101 including a laminated substrate 103A, a convex warp of which to the circuit board 133 side is large, as shown in FIG. 11. Therefore, there is fear that the cracks are generated in the outer peripheral portion of the joining material 104. The warp of the laminated substrate 103A occurs due to, for example, the difference between the total volume of the circuit board 133 and the total volume of the metal plate 132.
Even in the case of the laminated substrate 103A, where the convex warp at the circuit board 133 side is large, it is possible to prevent the generation of cracks by increasing the height of the projections 121 and increasing the thickness of the outer peripheral portion of the joining material 104. However, the increase in the height of the projections 121 also leads to an increase in the thickness of the central portion of the joining material 104 which is not high in heat conductivity. Therefore, there is fear that the heat conductivity from the metal plate 132 to the base plate 102 deteriorates, and that the heat dissipation property from the semiconductor chips 105 to the external deteriorates.
PTL 1 describes a semiconductor device wherein a projection on a base plate is positioned in a region separated 1 to 10 mm from the peripheral edge of a circuit board of a laminated substrate, and a groove of a rectangular shape in section is provided on the side closer to the peripheral edge than the projection. Even in the case of a laminated substrate whose warp is large, the groove serves to maintain the thickness of a joining material between the base plate and the circuit board of the laminated substrate. However, the groove of the base plate described in PTL1 has a space of a rectangular shape in section. As the region in the groove in which the joining material is thick is wide when the groove is rectangular, there is a room for improvement in the heat dissipation property from the laminated substrate to the base plate. Also, the groove described in PTL 1 is such that it is difficult for voids in the joining material to come out when joining, and that there is a room for improvement in the reliability of the joining material.
Also, PTL 2 describes a semiconductor device wherein grooves are formed in a surface of a base plate in order to bring the base plate into close contact with a heat sink, thereby controlling the warped shape of the base plate. However, the grooves described in PTL 2 do not contribute effectively to an adjustment of the thickness of a joining material.


A photocatalytic reactor for processing selected reactants from a fluid medium comprising at least one permeable photocatalytic membrane having a photocatalytic material. The material forms an area of chemically active sites when illuminated by light at selected wavelengths. When the fluid medium is passed through the illuminated membrane, the reactants are processed at these sites separating the processed fluid from the unprocessed fluid. A light source is provided and a light transmitting means, including an optical fiber, for transmitting light from the light source to the membrane.

This invention relates generally to photocatalytic reactors and more particularly to a photocatalytic reactor having at least one permeable photocatalytic membrane. The United States Government has rights to this invention pursuant to Contract No. DE-AC05-840R21400 with Lockheed Martin Energy Systems, Inc. awarded by the U.S. Department of Energy.
The use of photocatalysis for in situ environmental remediation and other applications is a growing area of research. In the process of photocatalysis generally, the illumination of the surface of a photocatalyst, such as an oxide semiconductor, produces chemically active sites associated with excited electron-hole pairs. The positive holes migrate to the semiconductor surface and participate in oxidation reactions, while the electrons are scavenged by an oxidizer such as oxygen. The complete mineralization (reduction to CO.sub.2, H.sub.2 O, and halogen ions) of many halogenated organics such as trichloroethylene has been shown to proceed by these oxidation-reduction reactions at such active sites on the photocatalyst surface.
In photocatalysis, the molecule to be changed must contact or closely approach the photocatalyst surface. Most photocatalysis research to date has used slurries of small titanium dioxide particles, mixed with the dissolved substances of interest, in order to keep the titanium dioxide photocatalytic surfaces as close as possible to the molecules dissolved in the slurry. However, because subsequent recovery of particles of photocatalyst from a treated liquid can be difficult and creates an additional step, various methods for immobilization of the photocatalyst have been attempted. Such methods include coating the photocatalyst on glass beads, inside tubes of glass or Teflon, on fiberglass, or on woven mesh. In these systems, however, the convenience of catalyst immobilization is achieved at the expense of increased average convective-diffusion distance from fluid to catalyst surface.
Some research has focused on the use of inorganic ceramic membranes as a means by which to fix the photocatalyst. By immobilizing the photocatalyst in a membrane, molecules to be treated are brought into contact with the photocatalytic surface as the liquid passes through the membrane, thus allowing for continuous processing and decreased diffusion distances. U.S. Pat. No. 5,035,784, issued Jul. 10, 1991, describes the degradation of organic chemicals with a titanium ceramic membrane. However, this patent discloses a "membrane" comprised of a porous film coated on a non-porous glass substrate, such as beads or slides. Because the glass substrate is not porous, a constant concentration gradient is required to drive the contaminant reactants into the pores of the film. As the concentration of contaminant reactants decreases exponentially with time, the decomposition rate decreases. As a result, this system cannot completely eliminate the presence of contaminant reactants, and thus the effective efficiency of the system decreases over the duration of the reaction.
Surface illumination is another important aspect of photocatalysis. In U.S. Pat. No. 5,035,784 and in other work addressing the use of photocatalysis for decomposition of contaminants, large ultraviolet lamps are used to illuminate the photocatalyst, whether fixed on a support or as a slurry. Such lamps are limited in that they cannot effectively illuminate the membrane, particularly if the membrane is small (i.e. a few millimeters) and if in situ remediation is desired. The use of a large lamp in such a system also has disadvantages in that the system is not easily scaled up for in situ use.
In the above-referenced patent, a light delivery system comprising an optical fiber coated with a photocatalyst is also described. However, the use of a coated optical fiber has disadvantages in that the photocatalyst is coated on a non-porous support, and the contaminants cannot flow through such a support, thereby decreasing the efficiency of the process. Moreover, in this system, the photocatalytic coating is illuminated from the back, and thus, direct illumination of the surface of the photocatalyst is not possible. Such a configuration decreases the effectiveness of the process because fewer chemically active sites can be formed.
Accordingly, a need in the art exists for a photocatalytic reactor having at least one permeable photocatalytic membrane which permits either a gas or liquid fluid medium containing selected reactants to flow through the membrane so that the chemically active sites on the surface of the permeable photocatalytic membrane will have constant contact with the reactants and a light transmission system which directly illuminates the membrane, allows for in situ use of the photocatalytic reactor, and allows the reactor to be easily scaled to a particular application.

The United States of America as represented by the United States Department of Energy


Methods to control electrical resistivity in filler-polymer compositions are described using dual phase fillers. Polymer compositions containing the dual phase fillers are further described.

The present invention relates to fillers and fillers in filler-polymer compositions. The present invention further relates to filler-polymer compositions with controlled electrical resistivity and methods to control resistivity in filler-polymer compositions.
In making filler-polymer compositions, there is a desire to have certain electrical resistivity, such as volume resistivity and/or surface resistivity, in the filler-polymer composition for various uses. The desired range of electrical volume resistivity depends on a particular application and, for example, can be in the range of from 101 to 1018 Ohm*cm. A typical volume resistivity value for some commercial polymers is in the range of from 1012 to 1018 Ohm*cm. Conductive filler, such as carbon black, is frequently added to lower electrical resistivity of particle-polymer composition, also referred to as a composite. A sharp change in resistivity of the composite happens when the concentration of carbon particles reaches a critical value at which continuous conductive paths are formed.
The resistivity of composites can be affected by the chemical functionalization of the carbon black, for instance, by use of diazonium chemistry, where an alkyl-containing or aromatic-containing group is attached onto the carbon black. U.S. Published Patent Application No. 2006/0084751 A1 provides some examples of certain types of chemical functionalizations of the carbon surface via diazonium chemistry with non-polymeric organic groups. While this chemical functionalization has been quite useful and an important advancement in filler-polymer compositions, the chemical functionalization of carbon black can have a disadvantage in that the chemical groups attached onto the surface of the carbon black are sensitive to high temperatures. For instance, at temperatures above 150° C., the chemical groups attached onto the carbon black may be destroyed, which can lead to the loss of resistivity performance. Since some filler-polymer compositions are made or are preferably made in high temperature processing or subjected to high temperatures in post-processing, it would be helpful to have alternative solutions to controlling electrical resistivity in filler-polymer compositions which are less sensitive to high temperature processing.
Further, it would also be desirable to have a filler which can permit control of electrical resistivity in a polymer composition. Such fillers would have benefits in various applications, such as the ones exemplified below:
One application is with electrophotographic composites, which can benefit from the fillers that can tune polymer film surface resistivity to, for instance, 106-109 Ohm/sq range. Such an intermediate range of resistivity for electrophotographic composites (rolls and belts) can be important for proper operation, specifically to transfer charged toner particles and develop images. Generally, such composites want to avoid being too conductive or too resistive.
Another example is in electronic industrial formulations (such as black inks, adhesives, etc), where the color and high electrical resistivity can be important. There is a need for high resistivity carbon blacks to insure proper operation of electronic parts and avoid short circuits when carbon black particles are not perfectly dispersed in the formulations.
One of the major uses of carbon black particles is in reinforcing rubber polymers (tire applications). Typically, a reinforced polymer composite (for example, a tire) has about 30 wt % of carbon black. Such a high concentration of carbon black particles leads to electrical percolation of the composite, which is used in certain rubber applications to dissipate the electrostatic charges. However, there are applications that can benefit from reinforced polymers that are also electrically resistive, such as applications related to insulative rubber composites, insulative polymer composites, various insulative adhesive, and sealant formulations.
Thus, it would be desirable to control electrical resistivity in filler-polymer compositions, including the more difficult regions, as shown in FIG. 1, regions 1 and 2. It would also be desirable to have a filler which can permit control of electrical resistivity in a filler-polymer composition and which is more dispersible in certain types of chemistries, such as silicone-type chemistries.
Accordingly, there is a need to overcome the disadvantages mentioned above and to provide methods to control electrical resistivity in filler-polymer compositions in order to achieve a desired resistivity range, particularly methods which are not dependent on the chemical functionalization of conductive filler particles alone or at all. Further, there is a need to provide filler-polymer compositions with controlled electrical resistivity that are more dispersible in various types of polymer compositions, including silicone polymer compositions.
Carbon black is frequently added to polymers to improve polymer stability against the damaging UV and/or IR light. At the same time, the electrical resistivity of such a composite is affected, which is highly undesirable for certain applications. Accordingly, there is a need to provide methods to control electrical resistivity in such a manner that one is able to maintain the electrical resistivity level of the original polymer at any loading of an optically dense carbon type filler.

Methods to control electrical resistivity in filler-polymer compositions and products related thereto


Methods and apparatuses for forming a dual damascene structure utilizing a selective protection process to protect vias and/or trenches in the dual damascene structure while removing a hardmask layer from the dual damascene structure. In one embodiment, a method for removing a patterned hardmask layer from a substrate includes forming an organic polymer material on a dual damascene structure that exposes substantially a patterned hardmask layer disposed on an upper surface of the dual damascene structure, removing the patterned hardmask layer on the substrate, and removing the organic polymer material from the substrate.

1. Field
Embodiments described herein generally relate to methods and apparatuses for forming semiconductor devices. More particularly, embodiments described herein generally relate to methods and apparatuses for manufacturing an interconnect structure for semiconductor devices utilizing a selective protection process during a pattering process.
2. Description of the Related Art
Reliably producing nanometer and smaller features is one of the key technology challenges for next generation very large scale integration (VLSI) and ultra large-scale integration (ULSI) of semiconductor devices. However, as the limits of circuit technology are pushed, the shrinking dimensions of VLSI and ULSI interconnect technology have placed additional demands on processing capabilities. Reliable formation of gate structures on the substrate is important to VLSI and ULSI success and to the continued effort to increase circuit density and quality of individual substrates and die.
As the dimensions of the integrated circuit components are reduced (e.g., to nanometer dimensions), the materials used to fabricate such components must be carefully selected in order to obtain satisfactory levels of electrical performance. For example, when the distance between adjacent metal interconnects and/or the thickness of the dielectric bulk insulating material that isolates interconnects have nanometer dimensions, the potential for capacitive coupling between the metal interconnects is high. Capacitive coupling between adjacent metal interconnects may cause cross talk and/or resistance-capacitance (RC) delay which degrades the overall performance of the integrated circuit and may render the circuit inoperable. In order to minimize capacitive coupling between adjacent metal interconnects, low dielectric constant bulk insulating materials (e.g., dielectric constants less than about 4.0) are needed. Examples of low dielectric constant bulk insulating materials include silicon dioxide (SiO2), silicate glass, fluorosilicate glass (FSG), and carbon doped silicon oxide (SiOC), among others.
A patterned mask, such as a photoresist layer or a hard mask layer, is commonly used to etch structures, such as gate structures, shallow trench isolation (STI), bit lines and the like, or back end dual damascene structures on a substrate. The patterned mask is conventionally fabricated by using a lithographic process to optically transfer a pattern having the desired critical dimensions to a layer of photoresist. The photoresist layer is then developed to remove undesired portions of the photoresist, thereby creating openings in the remaining photoresist.
However, the patterned mask, which is typically formed on an upper surface of the structure to be etched, often contribute an increase of the trench/via aspect ratio, which creates challenge for the metal gap filling process. As such, it is often desired to remove the patterned mask from the substrate prior to the metallization process so as to lower the aspect ratio of the vias/trenches to facilitate metal filling into the vias/trenches during the metallization process. Conventionally, dry etching or wet etching process can both be utilized to remove the patterned mask. However, conventional processes often adversely damage sidewalls or features in the interconnect structure, resulting in line collapse or profile deformation.
Damage caused to the structure may result in inaccurate critical dimension of the feature formed on the substrate may result in poor electrical properties of the device. Poor electrical properties of the device may impact not only the electrical performance of the devices, but also on the integration of the interconnection structure, including insulating materials and conductive materials, which may eventually lead to device failure.
Thus, there is a need for improved methods to selectively control and protect certain areas of the structures on a substrate from damage during a patterned mask removal process.

Methods for forming interconnect structure utilizing selective protection process for hardmask removal process


An apparatus for specifying three-dimensional coordinates of a body includes an image position sensing unit for converging a light radiating from a specific body arranged in a space on a plane to form an image and detecting a position of the image on the plane, one or a plurality of mirrors for reflecting the light from the specific body to allow the reflected light to enter the image position sensing unit, and a coordinate calculating unit for calculating coordinates of the specific body in a three-dimensional coordinate system defined in a three-dimensional space based on the positions of the images respectively formed by a light radiating from the specific body and directly entering the image position sensing unit and a light reflected by the mirror and entering the image position sensing unit.

1. Field of the Invention
The present invention relates generally to a system for use in information apparati such as computers and measuring apparati, for specifying coordinates of a body in three-dimensional space, and more particularly, it relates to an improvement in a technique for specifying coordinates of a body by using radiation of light and the like.
2. Description of the Related Art
With the development of electronic technology in the field of computers etc., systems employing three-dimensional space have been increased in number. The most typical one of such systems is the virtual reality (hereinafter referred to as "VR") system.
The VR system enables a person to have a similar experience in artificial reality to a real experience. The following literatures describe such virtual reality:
(1) "Virtual Environment" by Michitaka Hirose, Proceedings of the 6th Human Interface Symposium (1990);
(2) "Generation of Artificial Reality" by Michitaka Hirose, System/Control/Information, vol. 33, No. 11, pp. 590-597 (1989); and
(3) "How Far Virtual Reality Will Be Realized" by Michitaka Hirose, Journal of the Japan Society of Mechanical Engineers, vol. 93, No. 863, pp. 72-78 (1990)
For the VR system, it is essentially important to input a position and posture of a person to the system with accuracy and at a high speed. Various attempts have been made to accurately specify coordinates of a person at high speed.
FIG. 1 shows one example of such a VR system employing coordinate input system. The system is described in the above-described literature (1).
With reference to FIG. 1, the VR system includes a space sensor 102 attached to the head of a person 100, liquid crystal glasses 104 which the person 100 puts on, a data glove 106 which the person 100 puts on his hand, a space sensor controller 108 for controlling the space sensor 102, a data glove controller 110 for controlling the data glove 106, a graphics and world controller 112 for subjecting a world model 128 to predetermined processing to adapt virtual reality to the person's movements according to a position and posture of the person and a position and posture of his finger input respectively from the space sensor controller 108 and the data glove controller 110, a stereo display controller 114 for producing video to be applied to the person 100 based on the world model 128, a stereo display 116 for performing stereoscopic display of a virtual body 118 in response to a signal applied from the stereo display controller 114, a synchronization signal transmitter 126 for alternately opening/closing right and left liquid crystal shutters of the liquid crystal glass 114 in synchronization with a display cycle of the virtual body 118 in response to a synchronization signal from the stereo display controller 114, a halfmirror 120 disposed in front of the person 100, and a force feedback controller 124 for controlling a force feedback head 122 such that force is applied against the data glove 106 and the hand of the person 100 according to the world model 128.
The VR system shown in FIG. 1 operates as follows. The space sensor 102 and the space sensor controller 108 detects position/posture of the head of the person 100 and applies their three-dimensional coordinates to the graphics and world controller 112. The data glove controller 110 detects movements of the person's (100) hand and applies information indicative of the posture and the position of the hand to the data glove controller 110. The data glove controller 110 processes the signal to generate a signal indicative of coordinates of a position of the person's (100) hand and a state of each articulation and applies the signal to the graphics and world controller 112.
The graphics and world controller 112 determines how to change the world model 128 based on the information indicative of position/posture of the head and the hand of the person 100 and the information of the world model 128 representing the former virtual reality. The world model 128 is subjected to a predetermined processing based on the determination.
The stereo display controller 114 generates stereoscopic video to be applied to the person 100 according to a new world model 128. The stereoscopic video signals includes a pair of video, one for the person's right eye and the other for the left eye. The stereo display 116 alternately displays the video for the right eye and video for the left eye at predetermined intervals. The displayed virtual body 118 is reflected by the halfmirror 120, which reflection enters the eye of the person 100 as a virtual body 132. At this time, the synchronization signal transmitter 126 opens the right side shutter of the liquid crystal glass 104 when the video for a right eye is displayed and the left side shutter when the video for a left eye is displayed, with the other shutter closed. As a result, the video for a right eye and the video for a left eye are respectively applied to the right eye and the left eye of the person 100. The person 100 recognizes the virtual body 132 as being stereoscopic.
The force feedback controller 124 determines reactive force to be applied to the hand of the person 100 according to the world model 128. The force feedback controller 124 operates the force feedback head 122 based on the determined reactive force to press the hand of the person 100 with the data glove 106 put thereon. As a result, the person 100 feels as if he actually touched the virtual body 132.
It is clear that finding the accurate position of the person 100 is important for the above-described VR system. For this, one used as the space sensor 102 is shown in FIG. 2. With reference to FIG. 2, the position detection system includes a source coil 134, a sensor coil 136, a detection circuit 138, a computer 140 and a drive circuit 142. Each of the source coil 134 and the sensor coil 136 includes three Helmholtz coils arranged orthogonal to each other.
The three coils of the source coil 134 generate magnetic field in a time divisional manner. The sensor coil 136 senses the magnetic field generated by the source coil 134. The output of the sensor coil 136 is detected by the detection circuit 138 and applied to the computer 140. The computer 140 computes spatial position and posture of the sensor coil 136 based on nine pieces of information (3.times.3) obtained from the output of the sensor coil 136. The computed information is output through the computer 140.
The system shown in FIG. 2, however, has following shortcomings. First, the system is incapable of detecting a position of a body in the entire space. Second, the system operates so slowly that movements of virtual reality cannot be precisely changed in accordance with the user's movements. Furthermore, in the system, when a metallic body exists in measurement space, a magnetic field change caused by the metallic body leads to an error in a measured value.
The data glove 106 for use in the system shown in FIG. 1 can also measure coordinates of a tip of a finger, for example.
With reference to FIG. 3, the data glove 106 includes glove main body 144, a space sensor 146 attached to the back of the glove main body 144 such as shown in FIG. 2, and an optical fiber sensor 150 attached to the glove 144 along the respective fingers of the glove 144 by a fiber stopper 148. The optical fiber sensor 150 enables input equivalent to 2 degrees of freedom per finger, that is, the input equivalent to the total of 10 degrees of freedom to be obtained. Furthermore, an additional use of the space sensor 146 allows the data glove 106 to obtain information equivalent to 16 degrees of freedom including position/posture of the hand. Then, coordinates of a position of the tip of a predetermined finger can be specified by adding the output of the position sensor 146 and the multiplication of the output of the optical fiber sensor 150. Based on the same principle, a suit called a data suit has been made public which is capable of measuring movements of the entire body.
A device such as the data glove has an excellent function of converting minute movements into corresponding information. On the other hand, such device requires a power source to be supplied to a part itself for designating a spatial position and a sensor to be provided. As a result, the system is made large in scale as a whole. In addition, such device allows recognition of coordinates only in limited range of space.
Another attempt is a system as shown in FIG. 4. With reference to FIG. 4, the system includes a mouse pen 152 which can be freely moved in space by a person's hand and has a light emitting position 156, and two pairs of light receiving portions 154 for receiving a light from the light emitting portion 156. As each of the light receiving portions 154, a conventional camera can be used. The respective light receiving portions 154 in the system shown in FIG. 4 includes a lens 158 and a light receiving element 160. A filter 164 is provided on the light receiving element 160. The light receiving element 160 and the lens 158 are located to have their axes cross each other at a predetermined angle.
In the system shown in FIG. 4, a light from the light emitting portion 156 of the mouse pen 152 passes through the lenses 158 to enter the pair of light receiving elements 160. The incident angle of the light onto the light receiving element 160 is changed according to a position of the light emitting portion 156. The light incident angle can be found by the position of the image of the light emitting portion 156 formed on each light receiving element 160. A position of the light emitting portion 156 of the mouse pen 152 can be found based on the incident angle and a distance between the light receiving elements 160 on the principle of trigonometrical survey. The filter 164 serves to apply only light emitted from the light emitting portion 156, out of the incident lights, to the light receiving element 160.
The system shown in FIG. 4, however, requires two light receiving elements or cameras. This makes the device complicated and large in scale. In addition, when a distance between light receiving elements or cameras must be changed, it is difficult to adapt the system to new conditions with ease. Furthermore, the pen 152 for pointing out a specific point in space and having the light emitting portion 156 requires a power source to be provided therewith for operating the light emitting portion 156. In addition, the lens 158 and the light receiving element 160 arranged to have their axes crossing to each other at a predetermined angle has a narrow space wherein coordinates can be designated.

Apparatus for specifying coordinates of a body in three-dimensional space


A video library is formed within a personal video depot (PVD). The PVD has capability to accept purchased video's and DVD's as well as personal video's captured on camcorders. The purchased video's and DVD's are rights verified and assigned to a user having an authenticated ID. The PVD has capability to play a selected video on a TV as well as acquire additional video titles from the server connected to the depot through a network. A menu is displayed on a TV from which a remote control is used to make selections that affect the purchase of video titles and operation of the PVD.

1. Field of Invention
The present invention relates to multimedia systems, and in particular personal multimedia systems used to form libraries of multimedia including video and audio files.
2. Description of Related Art
In today's environment it is important to use commercially produced multimedia, i.e. analog and digital video, DVD's and CD's, in a manner consistent with industry license standards. Building personal libraries often consists of a rack of DVD and CD disks that are separately loaded into a player having one or more slots to hold the disks. Unless an individual creates a cataloging scheme, it is sometimes difficult to find a particular DVD or CD. Once a DVD containing a movie has been viewed, reviewing may not be as frequent as listening to a CD containing favorite music and the library of DVDs grows without frequent reuse.
A solution to the growing DVD library, which consumes space and requires physical organization, is to store video content into a personal video library and index the videos for future use. A user verification and a rights verification included in the personal video library guarantees the storage and use of the video's according to industry license standards.
U.S. Pat. No. 6,799,226 (Robbin et al.) is directed to techniques for rendering a peripheral device, which includes a data storage device, capable of being unplugged without preparatory user actions. U.S. Pat. No. 6,665,797 B1 (Keung) is directed to a program for providing identity information of the rightful user for accessing a network central computer to obtain services and/or software products. In U.S. Pat. No. 6,654,540 B2 (Artigalas et al.) a method and device is directed to a recording and reading apparatus constituting a video reservoir in the home of the consumer. In U.S. Pat. No. 6,275,936 B1 (Kyojima et al.) a method and apparatus is directed to access right authorization.
U.S. Pat. No. 6,587,403 (Keller et al.) is directed a music jukebox, which is configured for storing therein a music library. US 2004/0224638 (Fadell et al.) is directed to a media player system comprising a docking system, wireless capability, media storage and performing as a handheld music player. In U.S. Pat. No. 5,586,186 (Yuval et al.) a method and system is directed to controlling unauthorized access to information distributed to a user. U.S. Pat. No. 4,949,187 (Cohen) is directed to a video communication system that allows users to download a movie in digital format and store the movie locally for viewing at any time.