An acrylic resin composition suitable for the preparation of capstock for siding panels and having excellent impact resistance, weatherability and processability and a low gloss, which comprises 30 to 100% by weight of an impact modifier having a multilayer structure and 0 to 70% by weight of a methyl methacrylate homopolymer or copolymer and whose MFI (melt flow index measured according to ASTM D-1238 at 230xc2x0 C. and a load of 3.8 kg) is no more than 0.2 g/10 minutes.

The present invention relates to a resin composition for capstock containing an impact modifier having a multilayer structure as a main component, and more particularly to a resin composition suitable for producing capstock having excellent impact resistance, weatherability and processability and a low gloss by using a multi-manifold die.
It is well known that acrylic resins are excellent in weatherability. By utilizing this feature, acrylic resins have been used as a capstock for materials which require a weatherability. For example, U.S. Pat. No. 4,198,520 discloses improving the weatherability of materials having a poor weatherability such as ABS resin and PVC by applying an acrylic resin as a capstock to the surface of the materials. Further, U.S. Pat. No. 5,318,737 and WO 00/08098 disclose that an acrylic resin composition suitable for the production of capstock having excellent weatherability and impact resistance is obtained by adding a rubber component to an acrylic resin.
Although these products have been used in the market, however, it is hard to say that they sufficiently meet demands of the market in a field which requires a low gloss, since they have a high gloss peculiar to acrylic resins.
As a method of lowering the gloss are known addition of an inorganic material such as silica or talc, addition of a styrenic block copolymer such as SBS (styrene-butadiene-styrene block copolymer), SB (styrene-butadiene block copolymer), SEBS (styrene-ethylene-butylene-styrene block copolymer) or SIS (styrene-isoprene-styrene), addition of an olefin rubber such as EPR (ethylene-propylene rubber) or EPDM (ethylene-propylene-diene rubber), addition of NBR (nitrile rubber), and the like. However, the addition of these materials is unfavorable because of bringing about lowering of impact resistance or weatherability, although the gloss is reduced thereby.
Also, with respect to the processing method, coextrusion using feed block die is disclosed, for example, in U.S. Pat. No. 5,318,737. Since the viscosity of respective layers must be matched with each other, the melt characteristics of acrylic resin compositions are restricted, and the U.S. patent discloses that MFI must be from 0.4 to 0.75 g/10 minutes. WO 00/08098 does not limit the processing method, but discloses that MFI is not less than 1.5 for obtaining good products. However, if MFI is not less than 0.4, the obtained products have a high gloss and, therefore, are not applicable to uses requiring a low gloss. That is to say, it is required for obtaining low gloss products to increase the viscosity, but resins having an MFI of not more than 0.2 g/10 minutes are not processed to give good products by coextrusion using a feed block die which has been popularly used. Thus, it is difficult to achieve an excellent processability and a low gloss together.
Like this, it is very difficult to stably produce products having a low gloss and a beautiful surface with the impact resistance being maintained. It is the actual situation that there has not been provided a capstock made of an acrylic resin as a main component having impact resistance, weatherability, processability and low gloss that can sufficiently satisfy the demands of the market.
It is an object of the present invention to solve the problems mentioned above and to provide a capstock having excellent impact resistance, weatherability and processability and a low gloss which cannot be achieved by conventional acrylic resins.
A further object of the present invention is to provide an acrylic resin composition having an excellent processability suitable for the production of low gloss capstock.
The present inventors have found that an acrylic resin composition having an MFI (melt flow index) of not more than 0.2 g/10 minutes and comprising a multilayer structure polymer having a very high viscosity and a very high elasticity, which can serve as an impact modifier, and optionally a methyl methacrylate copolymer has an excellent processability and can provide a capstock having excellent impact resistance and weatherability and a low gloss by coextrusion using a multi-manifold die
Thus, the present invention provides:
(1) a resin composition suitable for extrusion to prepare a capstock using a multi-manifold die comprising 100 to 30 parts by weight of an impact modifier having a multilayer structure and 0 to 70 parts by weight of a methyl methacrylate polymer comprising 50 to 100% by weight of methyl methacrylate and 50 to 0% by weight of a copolymerizable monomer, the total of said impact modifier and said methyl methacrylate polymer being 100 parts by weight and said composition having an MFI (melt flow index measured according to ASTM D-1238 at 230xc2x0 C. and a load of 3.8 kg) of not more than 0.2 g/10 minutes;
(2) the composition of item (1), which comprises 20 to 60 parts by weight of said methyl methacrylate polymer and 80 to 40 parts by weight of said impact modifier, the total thereof being 100 parts by weight;
(3) the composition of item (1), wherein said methyl methacrylate polymer comprises 5 to 90% by weight of a methyl methacrylate polymer having a molecular weight of not less than 500,000 and 95 to 10% by weight of a methyl methacrylate polymer having a molecular weight of less than 500,000;
(4) the composition of item (1), wherein said impact modifier is a polymer having two layer structure prepared by polymerizing 50 to 15 parts by weight of a monomer mixture comprising 50 to 100% by weight of a (meth)acrylic ester and 50 to 0% by weight of a copolymerizable monomer in the presence of 50 to 85 parts by weight of a crosslinked acrylic rubber;
(5) the composition of item (1), wherein said impact modifier is a polymer having three layer structure prepared by polymerizing 30 to 60 parts by weight of a monomer mixture comprising 50 to 99.9% by weight of an alkyl acrylate, 50 to 0% by weight of a copolymerizable monomer and 0.1 to 5% by weight of a crosslinking monomer in the presence of 10 to 40 parts by weight of a polymer prepared by polymerization of 80 to 99.9% by weight of methyl methacrylate, 20 to 0% by weight of a copolymerizable monomer and 0.1 to 5% by weight of a crosslinking monomer to give a two-layered polymer, and then polymerizing 10 to 60 parts by weight of a monomer mixture comprising 50 to 100% by weight of a (meth)acrylic ester and 50 to 0% by weight of a copolymerizable monomer in the presence of said two-layered polymer;
(6) the composition of item (1), wherein said capstock is a capstock for a siding panel made of polyvinyl chloride; and
(7) a siding panel obtained by extrusion using the composition of item (1) as a capstock and a vinyl chloride resin as a substrate.
The acrylic resin composition of the present invention comprises 0 to 70 parts (parts by weight, hereinafter the same) of a methyl methacrylate polymer comprising 50 to 100% (% by weight, hereinafter the same) of methyl methacrylate and 50 to 0% of a copolymerizable monomer and 100 to 30 parts of an impact modifier having a multilayer structure (the total being 100 parts), and the composition has an MFI (melt flow index measured according to ASTM D-1238 at 230xc2x0 C. and a load of 3.8 kg) of not more than 0.2 g/10 minutes. The acrylic resin composition is suitable for the production of capstocks by extrusion using a multi-manifold die.
The methyl methacrylate polymer includes homopolymer and copolymers obtained by polymerization of 50 to 100% of methyl methacrylate and 50 to 0% of a monomer copolymerizable therewith. If the amount of methyl methacrylate is less than 50%, the effect of improving the weatherability of capstock moldings is insufficient. The content of methyl methacrylate is preferably from 60 to 98%, more preferably from 75 to 95%. The monomers copolymerizable with methyl methacrylate include, for instance, aromatic vinyl compounds, acrylic esters, alkyl methacrylates other than methyl methacrylate, and the like.
Examples of the aromatic vinyl compounds are, for instance, styrene, xcex1-methylstyrene, chlorostyrene and other styrene derivatives.
Examples of the acrylic esters are, for instance, ethyl acrylate, butyl acrylate, n-octyl acrylate, 2-ethylhexyl acryalte and other alkyl acrylates.
These monomers may be used alone or in admixture thereof.
The methyl methacrylate polymer can be prepared by emulsion polymerization, suspension polymerization, bulk polymerization, solution polymerization and so on. Of these, bulk polymerization is particularly preferred from the viewpoint of decreasing the content of impurity in the polymer.
The impact modifier having a multilayer structure is a polymer having a multilayer structure obtained by polymerizing a vinyl monomer in a single stage or in two or more stages in the presence of particles of a rubbery polymer. The rubbery polymer includes, for instance, an acrylic rubber, a diene rubber, a silicone rubber and the like. Examples of the diene rubber are, for instance, polybutadiene rubber, isoprene rubber, SBR, NBR, and the like. Examples of the acrylic rubber are, for instance, butyl acrylate-based rubber, n-octyl acrylate-based rubber, 2-ethylhexyl acrylate-based rubber, and the like. Of these, acrylic rubbers are preferred from the viewpoint that the weatherability of obtained capstocks is not lowered. In general, these rubbers are used in the form of crosslinked rubber. Known crosslinking monomers are used as a compound for forming a crosslinked structure. Preferable examples of the crosslinking monomer are allyl methacrylate, allyl acrylate, diallyl maleate, diallyl fumarate, diallyl itaconate, monoallyl maleate, butadiene, divinyl benzene, and the like. These may be used alone or in admixture thereof.
The crosslinked rubber particles may further contain a hard polymer in the inner layer as a core of the particle.
The crosslinked acrylic rubbers are obtained, for example, by polymerizing a monomer mixture of 50 to 99.9% of an alkyl acrylate having a C4 to C8 alkyl group, 50 to 0% of a copolymerizable monomer and 0.1 to 5% of a crosslinking monomer. Examples of the monomer copolymerizable with the alkyl acrylate are, for instance, alkyl acrylates having a C1 to C3 alkyl group, aromatic vinyl compounds such as styrene, xcex1-methylstyrene, chlorostyrene and other styrene derivatives, alkyl methacrylates such as methyl methacrylate and ethyl methacrylate, vinyl cyanide compounds such as acrylonitrile, vinyl acetate, and other vinyl compounds. These monomers may be used alone or in admixture thereof. In case of forming a hard core as an inner layer of the crosslinked acrylic rubber, the above-mentioned monomer mixture is polymerized preferably in the presence of a hard polymer obtained by a polymerization, preferably emulsion polymerization, of a monomer mixture of 80 to 99.9% of methyl methacrylate, 0 to 50% of a copolymerizable monomer and 0.1 to 5% of a crosslinking monomer. Examples of the copolymerizable monomer used in the preparation of the hard polymer are alkyl (meth)acrylates other than methyl methacrylate, aromatic vinyl compounds such as styrene and other styrene derivatives, vinyl cyanide compounds and other vinyl compounds. These monomers may be used alone or in admixture thereof.
In general, the impact modifier having a multilayer structure is obtained by polymerizing 10 to 70% of a vinyl monomer in a single stage or in two or more stages in the presence of 90 to 30% of crosslinked rubber particles. The content of the crosslinked rubber particles in the obtained multi-layered polymer is preferably from 50 to 85%, more preferably from 60 to 80%, from the viewpoints of moldability and weatherability.
Examples of the vinyl monomer to be polymerized in the presence of the rubber polymer particles are, for instance, an alkyl methacrylate such as methyl methacrylate or ethyl methacrylate, an alkyl acrylate, e.g., an alkyl acrylate having a C1 to C8 alkyl group such as methyl acrylate, ethyl acrylate or butyl acrylate, an aromatic vinyl compound such as styrene, xcex1-methylstyrene, chlorostyrene, other styrene derivatives or vinyl toluene, a vinyl cyanide compound such as acrylonitrile or methacrylonitrile, a halogen-containing vinyl compound such as vinyl chloride, vinyl acetate, and the like. The polymerization for the multi-layered polymer is conducted by emulsion polymerization, suspension polymerization, bulk polymerization, solution polymerization and the like. Emulsion polymerization method is preferred from the viewpoint that control of polymer structure is easy.
As an impact modifier having a multilayer structure are preferably used a two-layered polymer obtained by polymerizing 50 to 15 parts of a graft monomer mixture of 50 to 100% of a (meth)acrylic ester and 50 to 0% of a copolymerizable monomer in the presence of 50 to 85 parts of a crosslinked acrylic rubber (the total of the rubber and the monomer mixture being 100 parts); and a three-layered polymer obtained by polymerizing 10 to 60 parts of a graft monomer mixture of 50 to 100% of a (meth)acrylic ester and 50 to 0% of a copolymerizable monomer in the presence of a crosslinked acrylic rubber having a two layer structure obtained by polymerizing 30 to 60 parts of a monomer mixture of 50 to 99.9% of an alkyl acrylate having a C4 to C8 alkyl group, 50 to 0% of a copolymerizable monomer and 0.1 to 5% of a crosslinking monomer in the presence of 10 to 40 parts of a hard polymer which forms a hard core (the total of the core layer, the rubber layer and the graft layer being 100 parts). As the copolymerizable monomer in the graft monomer mixture are used vinyl monomers as mentioned above copolymerizable with the (meth)acrylic esters.
The methyl methacrylate polymer mentioned above is preferably a combination of at least two polymers having a different molecular weight. That is to say, there is suitably used a mixture of preferably 10 to 95%, more preferably 30 to 80%, of a methyl methacrylate polymer having a molecular weight of less than 500,000 and preferably 5 to 90%, more preferably 20 to 70%, of a methyl methacrylate polymer having a molecular weight of not less than 500,000. The molecular weight as used herein means a weight average molecular weight measured by GPC and calculated based on polystyrene having known molecular weights. The gloss lowering mechanisms by the methyl methacrylate polymer having a molecular weight of not less than 500,000 are assumed that one is to provide a resin with viscosity and elasticity and the other is to make a surface rough since it does not completely disperse into a methyl methacrylate polymer composed mainly of methyl methacrylate having a molecular weight of less than 500,000 and, as a result, is present in a size of several micrometers.
The resin composition of the present invention for extrusion into capstock comprises 0 to 70 parts, preferably 20 to 60 parts, of the above-mentioned methyl methacrylate polymer and 100 to 30 parts, preferably 80 to 40 parts, of the above-mentioned impact modifier having a multilayer structure. The composition comprising 20 to 60 parts of the methyl methacrylate polymer and 80 to 40 parts of the impact modifier having a multilayer structure is preferable from the viewpoint of a balance between the impact resistance and the processability. The resin composition of the present invention is characterized by its fluidity, and it is important that the composition has an MFI (melt flow index) of not more than 0.2 g/10 minutes measured according to ASTM D-1238 at 230xc2x0 C. and a load of 3.8 kg. The MFI of the composition is preferably from 0.01 to 0.15 g/10 minutes, more preferably from 0.03 to 0.1 g/10 minutes.
The process for preparing the acrylic resin composition of the present invention is not particularly limited, and the composition is obtained by mixing the methyl methacrylate polymer and the multi-layered impact modifier in a usual manner. The methyl methacrylate polymer and the multi-layered impact modifier may be prepared together by carrying out a graft polymerization to form a free polymer corresponding to the methyl methacrylate polymer.
The composition of the present invention may contain usual additives such as antioxidant, light stabilizer, lubricant, pigment and the like, as occasion demands.
Siding panels having excellent weatherability, impact resistance and processability and a low gloss can be obtained by using the acrylic resin composition of the present invention as a capstock.
Various thermoplastic resins such as vinyl chloride resins and ABS resins are used as a resin of the substrate for the capstock. Vinyl chloride resins are particularly preferred from the viewpoints of processability and weatherability.
The present invention is more specifically explained by means of the following Examples and Comparative Example. It is to be understood that the present invention is not limited to these Examples.


A perfectly or approximately lattice-matched semiconductor layer for use in an electronic or optoelectronic device. Perfectly lattice-matched (xe2x80x9cPLMxe2x80x9d) semiconductor layers prevent or lessen the formation and propagation of crystal defects in semiconductor devices, defects that can decrease the performance characteristics of the device. For some semiconductors, the ability to optimize composition-dependent properties over the wider range of compositions that approximately lattice-matched (xe2x80x9cALMxe2x80x9d) semiconductor layers allows is more advantageous than the lower strain and dislocation density encountered for PLM layers. In addition, PLM cell layers and ALM cell layers are also expected to result in improved radiation resistance characteristics for some semiconductor devices.

The present invention generally relates to semiconductor materials and, more particularly, to lattice-matched semiconductor materials for use in electronic and optoelectronic devices.
The interest in photovoltaic (xe2x80x9cPVxe2x80x9d) cells in both terrestrial and non-terrestrial applications continues as concerns over pollution and limited resources continue. Irrespective of the application, and as with any energy generation system, efforts have been ongoing to increase the output and/or increase the efficiency of PV cells. In terms of output, multiple cells or cells having different energy bandgaps have been stacked so that each cell or cell can absorb a different part of the wide energy distribution in the sunlight.
In the prior art, the need to achieve perfectly lattice-matched materials in semiconductor layers of a solar cell or other optoelectronic device is not recognized. Neither is the need to or to control very small amounts of strain in adjacent semiconductor layers. In fact, for example, in prior art examples growing gallium arsenide (xe2x80x9cGaAsxe2x80x9d) and gallium indium phosphide (xe2x80x9cGaInPxe2x80x9d) layers on a germanium (xe2x80x9cGexe2x80x9d) substrate, the lattice constant of the Ge had generally been thought to be sufficiently close to that of GaAs so that GaAs could be grown on a Ge substrate, and GaInP grown on the GaAs, with no detriment to the semiconductor properties.
In fact, the small lattice mismatch between GaAs and Ge causes crystal defects in the GaAs and in the bulk of cells. The presence of such crystal defects reduces the minority-carrier lifetimes in the bulk of the cells, increases the surface recombination velocity at interfaces, and creates possible shunting paths, all of which can reduce the current and voltage of photovoltaic devices, increase the reverse saturation current density and diode ideality factor of p-n junction in the device, and in general, degrade the performance of optoelectronic devices. Further, multi-junction solar cells and other optoelectronic devices having these crystal defects degrade under radiation.
Thus, it is highly desirable to prevent the formation of crystal defects in semiconductor layers and to increase the radiation resistance of multi-junction solar cells and other optoelectronic devices.
It is thus an object of the present invention to prevent the formation of crystal defects in semiconductor layers grown on a growth substrate. It is another object of the present invention to improve or change the characteristics of radiation resistance.
The above objects are accomplished by adding a small amount of an alloying element to a semiconductor material to manipulate the lattice constant of the semiconductor cell to become a perfectly lattice-matched (xe2x80x9cPLMxe2x80x9d) semiconductor that may be used for the base, emitter, back-surface field (xe2x80x9cBSFxe2x80x9d), window, tunnel junction, cap, buffer, and/or other cells in a device. In this context, PLM means that the lattice mismatch between the PLM cell and the growth substrate is less than 0.074%. If specified, PLM may also refer to a difference in lattice mismatch between the PLM cell and an adjacent cell of less than 0.074%.
The PLM semiconductors prevent the formation and propagation of crystal defects in semiconductor devices, or reduce their concentration dramatically. The presence of such crystal defects reduces the minority-carrier lifetimes in the bulk of the cells, increases the surface recombination velocity at interfaces, and creates possible shunting paths. These all can reduce the current and voltage of photovoltaic devices, increase the reverse saturation current density and diode ideality factor of p-n junction in the device, and, in general, degrade the performance of optoelectronic devices. The use of PLM semiconductor cells in the device eliminates or reduces these sources of non-ideal loss, and brings the device performance closer to theoretical limits. The higher degree of lattice matching and the presence of additional elements may be used to improve or change device radiation resistance.
In an alternative preferred embodiment, or in combination with the PLM solar cell layers, the solar cell layers may be grown approximately lattice-matched (xe2x80x9cALMxe2x80x9d) to each other and to the growth substrate. A layer is defined to be ALM if it has an unstrained lattice constant that differs from that of the adjacent subcell layers, or that of the substrate, by an amount greater than or equal to 0.074%, but less than about 0.3%. The ALM layers are thus layers grown with a small intentional mismatch to the substrate or the adjacent subcells.
For some semiconductors, the ability to optimize composition-dependent properties over the wider range of compositions that ALM allows is more advantageous than the lower strain and dislocation density encountered for PLM layers. The small intentional mismatch of ALM cell layers is also expected to result in greater radiation resistance for some semiconductors, so that the balance between high beginning-of-life (xe2x80x9cBOLxe2x80x9d) performance and radiation resistance may be optimized via the degree of small intentional mismatch, for a given solar cell radiation exposure and required service life.

Lattice-matched semiconductor materials for use in electronic or optoelectronic devices


The present invention provides GPCR polypeptides and polynucleotides, recombinant materials, and transgenic mice, as well as methods for their production. The polypeptides and polynucleotides are useful, for example, in methods of diagnosis and treatment of diseases and disorders. The invention also provides methods for identifying compounds (e.g., agonists or antagonists) using the GPCR polypeptides and polynucleotides of the invention, and for treating conditions associated with GPCR dysfunction with the GPCR polypeptides, polynucleotides, or identified compounds. The invention also provides diagnostic assays for detecting diseases or disorders associated with inappropriate GPCR activity or levels.

The invention relates to the fields of medicine and drug discovery.
Mammalian G protein coupled receptors (GPCRs) constitute a superfamily of diverse proteins with thousands of members. GPCRs act as receptors for a multitude of different signals. Chemosensory GPCRs (csGPCR) are receptors for sensory signals of external origin that are sensed as odors, pheromones, or tastes. Most other GPCRs respond to endogenous signals, such as peptides, lipids, neurotransmitters, or nucleotides. GPCRs falling in the latter group are involved in numerous physiological processes, including the regulation of neuronal excitability, metabolism, reproduction, development, hormonal homeostasis, and behavior, and are differentially expressed in many cell types in the body.
Of all currently marketed drugs, greater than 30% are modulators of specific GPCRs. Only 10% of GPCRs (excluding csGPCRs) are targeted by these drugs, emphasizing the potential of the remaining 90% of the gene family for the treatment of human disease.
Despite the importance of GPCRs in physiology and disease, the size of the GPCR superfamily is still uncertain. Analyses of genome sequences have generated markedly varied estimates (Venter, J. C. et al., Science 291, 1304-51 (2001); Lander, E. S. et al., Nature 409, 860-921 (2001); Takeda, S. et al., FEBS Lett 520, 97-101 (2002)). In addition, while most GPCRs are known to be selectively expressed in subsets of cells, the expression patterns of most GPCRs are incomplete or unknown. Thus, there is a need for GPCR polypeptides, polynucleotides, antibodies, genetic models, and modulating compounds for use in the treatment and diagnosis of a wide variety of disorders and diseases.

Method of identifying a compound for the treatment or prevention of obesity


A process for producing a pulp from cellulose-containing material, wherein the material is reacted with formic acid as the solvent, and cooked at approximately the boiling temperature of the solvent, whereby return condensation is used. Annual plants, deciduous or coniferous wood can be used as the cellulose-containing material. In one variant of the process, the cellulose-containing material is only slightly warmed, whereby backflow cooling is used, and then a precisely predetermined quantity of hydrogen peroxide is slowly added to the liquid at a constant rate. This process variant can be repeated at a lower cooking temperature. The pulp thus obtained is preferably utilized in the production of cellulose, and in particular in the production of paper or cardboard. It is proposed that the lignin, which is isolated from the cellulose-containing material, have further applications, whereby such lignin is, after the pulp has been separated from the solvent, itself precipitated out in water. The lignin thus obtained can be used as a new building material, as a filler material or as an output substance to be used in the manufacture of aromatic products.

The invention relates to a process for producing a pulp from cellulose-containing material, the pulp itself and its application.
By pulp is meant a cellulose mash that is used in the production of chemical pulp, which, in turn, is used to make paper or cardboard. The cellulose-producing industry today is finding it increasingly difficult to meet the environmental standards and requirements imposed on it. In addition, it is no longer permitted in Germany, by virtue of the environmental regulations of 1990, to use conventional processes for recovering cellulose, such as the sulphite process. In Germany today the sulphite process is the only process wherein sulphur-containing digestion agents are used to dissolve the lignin, which serves as a binder, out of the cellulose-containing material.
One result of efforts to develop more environmentally-friendly processes for recovering cellulose is the so-called Acetosolv process, in which the digestion liquid contains at least 50 percent by weight of acetic acid, to which is added a very small quantity of hydrochloric acid. Following digestion, the recovered pulp is washed with caustic soda and, if required, with organic solvents, in order to more or less completely remove the lignin.
The disadvantages of this process are the relatively high consumption of acetic acid, the use of caustic soda, and the organic solvents that may be needed to wash the pulp.
In accordance with the stringent requirements of the paper industry, the extracted pulp is regularly bleached in a subsequent step, in order to keep the Kappa number at the most below 25. Even the Acetosolv process includes downstream bleaching with peroxide, with respect to which it should be pointed out that high use is not advantageous.
EP 0 325 891 A1 discloses an improvement to this Acetosolv process. The improvement comprises in essence that the pulp be washed following the digestion step, not with caustic soda, but with a C.sub.1-3 -carboxylic acid, or with a mixture of such acids, whereupon the subsequent bleaching step is carried out in the existing acid medium, to which hydrogen peroxide or ozone is added. A carboxylic acid such as, for example, butyl acetate, can be used as the solvent. This patent also discloses that the C.sub.1-3 -carboxylic acid can later be re-used as a digestion liquid.
Disclosed in EP 0 250 422 B1 is a process commonly known as the Milox process, in which bleached pulp is produced from cellulose-containing material. In this process, digestion is accomplished in a peroxyformyl, peroxyaceto, peroxypropional or peroxybutyric acid medium, wherein recovery of peroxic acid is effected in that the acid used is mixed with a relatively large quantity of hydrogen peroxide, whereupon the digestion process continues. Following digestion, the pulp is bleached in an alkali solution to which hydrogen peroxide has been added. The disadvantage of this process, however, is the use of an alkali solution such as caustic soda, as well as the high proportion of hydrogen peroxide required.
Using this prior art as the basis, the present invention aims to develop a process for producing a pulp from cellulose-containing material that is environmentally-friendly, highly economical and efficient.

Method of producing a pulp from cellulosic material using formic acid and hydrogen peroxide


Business forms are sealed by pressure with reduced tenting and pillowing. Each form has a strip of pressure sensitive adhesive of a predetermined width. In an automatic continuous, sequential manner, upper and lower rollers operatively biased together by spring pressure activate the pressure sensitive adhesive to affix one part of the form to another. The force applied by the rollers is applied only to the approximate area of the predetermined width of the adhesive, not over the whole form. Conveyor tapes are associated with the rollers to facilitate conveyance of the forms, and a pressure of about 120 lbs. per lineal inch is applied to the pressure sensitive adhesive. A buckle or insert folder can be used to fold the forms, and they are then fed to a first pressure sealing module. A 90.degree. transfer conveyor conveys the forms from the first pressure sealing module to a second module, and from the second module they are removed by a discharge conveyor.

In the manufacture of business forms, it is almost always necessary to seal one part of the form construction with respect to another. This is typically accomplished by utilizing an adhesive which acts between the two portions of the business form to be fixed together. Oftentimes heat activated adhesives are utilized, but in many circumstances it is desirable to utilize pressure sensitive adhesives.
A sealing system for business forms used with one type of pressure sealing adhesive requires that the adhesive applied to the forms during manufacture be capable of cohesive bonding to a fiber tearing strength when pressure sealed after computer printing by the end user, but must be entirely free of adhesive bonding under all conditions of normal handling during manufacture, storage and imaging. Thus the margins of pressure applied to the paper during normal handling, and the pressure applied to effect fiber tearing bonds are widely separated.
A typical pressure sealing piece of equipment for use with business forms uses a multiple roll sealing system to apply pressure to the entire web (or the entire individual sheets) being processed. Those rolls are capable of exceeding the threshold unit pressure required, which is quite high, typically about 200 lbs. per lineal inch of paper width when using a succession of two or three pressure couples. This requires a very rigid yet accurate mechanical system. While the application of such high forces requires massive and precise construction of the sealer, it is also necessary that the web or sheet manifold be clean--that is that there be no disturbances in the surface configuration. Therefore it is extremely difficult to utilize such equipment with inserts, window patching, folds internal to the form, etc., since such build ups in thickness or non-uniformities in the surface characteristics decrease the unit pressure at the sealing edges and could increase the sealing pressure in the inclusion area so that a jam or physical tearing of the sheet occurs. When inserts are provided, there also is the problems of "tenting" or "pillowing".
According to the present invention, a method and apparatus are provided that overcome the problems associated with full-width pressure sealing systems. According to the present invention it is possible to continuously, and at high speed, act upon business forms including those having inserts, window patching, folds internal to the forms, and other surface non-uniformities. The "pillowing" effects (where the sealed manifold is forced apart), and the "tenting" effects (where various plies of the assembly shift relative to each other and thereby prevent formation of a completely flat form) are substantially avoided.
The general manner in which the desirable results are accomplished according to the invention is by effecting sealing along only the pressure sensitive adhesive strips of the business forms--rather than along the entire surface of the forms. This allows the coupling force between each sealing roll pair to be reduced from about 1,000 lbs. in the prior art, to about 100-200 lbs., dependent on the ratio of total form width to sealing bond width. This also allows production of a system that is much less massive than conventional, and one that is reliable and simple and easy to utilize.
According to one aspect of the present invention, a method of handling business forms is provided, each form having at least one strip of pressure sensitive adhesive of a predetermined width for affixing one part of the form to another part. The method comprises the step of (a) automatically, in a continuous, sequential manner, acting on successive individual business forms to apply a force to them sufficient to activate the pressure sensitive adhesive to fix one part of the form to another, the force being applied only to the approximate area of the predetermined width of adhesive. Typically the business forms would each have first and second generally parallel strips of pressure sensitive adhesive each of a predetermined width, and step (a) would be practiced so as to apply the activating force to the approximate areas of both strips of adhesive. The business form may have a third (or others) strip of pressure sensitive adhesive generally perpendicular to the first strip, and of a predetermined width. In a continuous and sequential manner, according to the method of the invention the form would be acted on to apply a force to the third strip, too, this force also being applied only to the approximate area of the predetermined width of the third adhesive strip. Prior to the practice of step (a), the business form may be initially configured by folding a sheet of paper to provide at least two plies. The paper may be V-folded, C-folded, or Z-folded. An insert may be inserted between the plies, in which case the adhesive activating step or steps are practiced so that activating force is not applied to any area of the business form containing the insert.
According to another aspect of the invention a pressure applying system for applying pressure to business forms to activate pressure sensitive adhesive associated with the forms is provided. The system comprises a frame, and a pressure applying device operatively connected to the frame. The pressure applying device comprising means for simultaneously applying pressure along a pair of spaced, generally parallel strips while simultaneously conveying business forms through the device, including two sets of narrow width upper and lower rollers. The upper roller of each set is disposed above and in peripheral engagement with the lower roller of that set along a common vertical center line. The pressure applying device also preferably further comprises a pair of conveyor transport belts or tapes, one associated with each set of rollers, and mounted interiorly of the rollers for assisting conveyance of business forms between the rollers. Each upper and lower roller preferably has a segment with an elastomeric material periphery to assist accurate rotary displacement of said upper and lower roller pairs.
According to a further aspect of the present invention, there is provided a first pressure sealing device comprising upper and lower rollers disposed on a common vertical centerline, and means for applying a force to the upper roller sufficient to effect activation of the pressure sensitive adhesive of the business forms acted thereon, the rollers having a width approximately equal to the predetermined width of a strip of pressure sensitve adhesive which they act upon (e.g. about 0.3-0.7 inches). A second pressure sealing device, substantially identical to the first device, is also provided. Feeding means feed business forms in a continuous manner to the first device upon exiting the first sealing mechanism. A 90.degree. transfer conveyor means continuously feeds business forms from the first device to a second similar sealing device; and, discharge conveyor means convey sealed forms away from the second device.
According to yet another aspect of the present invention a pressure applying distinct module is provided. The module comprises: A stationary frame, a lower roller, a first shaft for mounting the lower roller for rotation about a first generally horizontal axis, the axis being fixed with respect to the frame, and an upper roller. Also provided are: means for mounting the upper roller so that it is distinct from the first shaft and frame, but so that the upper and lower rollers are on a common vertical center line, and so that it is rotatable about a second generally horizontal axis, parallel to the first axis; and force applying means for applying a force between the frame and the upper roller so that the periphery of the upper roller is operatively pressed into engagement with the periphery of the lower roller. The first shaft is rotated about its axis of rotation by a motor.
The force applying means (e.g. spring or hydraulic) preferably applies sufficient force to the upper roller so that there is a pressure of about 100-200 lbs per lineal inch exerted by the rollers on the sheet material therebetween.
The rollers and the apparatus according to the invention typically are steel pressure wheel couples having a diameter of about three inches, and separated by a linear distance of about 31/2 inches. They have an operative peripheral width of about 0.3-0.7 inches (e.g. about 1/2 inch) so that they act only on that portion of the business form on which the strip of pressure sensitive adhesive is applied. Preferably horizontally spaced sets of rollers are provided so that multiple parallel strips of pressure sensitive adhesive can be acted upon at the same time, and the horizontal spacing between the rollers perpendicular to the direction of movement of the forms may be adjusted to accommodate forms of different dimensions. The second pair (in the direction of form movement) of rollers of each set is very slightly larger in diameter than the first, to provide a slight tension on the forms during conveyance.
It is the primary object of the present invention to provide for the effective high speed automatic sealing of business forms in a continuous, successive manner by applying pressure only to strips of pressure sensitive adhesive associated with the forms, and not other parts of the form. This and other objects of the invention will become clear from an inspection of the detailed description of the invention, and from the appended claims.

Pressure seal adhesive system with rollers


In accordance with some implementations, a method for responding to requests submitted through a conversational interface is disclosed. The method is performed on a server system having one or more processors and memory storing one or more programs for execution by the one or more processors. The server system receives a request from a user through a conversational interface. The server system determines, based on the request, whether the system is able to fulfill the request automatically. In accordance with a determination that the system is able to fulfill the request automatically, the server system fulfills the user request with no human interaction. In accordance with a determination that the system is not able to fulfill the request without human intervention, the server system sends the request to a human operator for fulfillment.

Over the last two decades, the number of online services has increased dramatically. Online services that have emerged include, for example, online commerce services and social networking services. These services open up new experiences for user, including interactions between users and new ways of shopping for goods and services. These services incur a positive network effect as more users sign up and use the service.
A source of inconvenience in the user experience is the provision of information by the user to the online service in order to make full use of the service. The online service asks for a certain amount of information upfront from the user at sign-up, and can subsequently ask for additional information. If the venue asks for too much information too quickly, the user is overwhelmed and becomes less likely to provide the information, less likely to stay with the service, or less likely to sign up for the service in the first place. Another source of inconvenience is the communication interface between the user and the online service. A user can use different modes of communication on any given day. Limiting the user to one mode of communication with the service inconveniences the user and limits the user's interaction with the service. Requesting information from the user without requesting too much too quickly, and providing multiple avenues or modes of communication with users, including avenues that has a conversational feel, make online services more convenient and user-friendly.


A vehicle lighting fixture can achieve uniform projection of light while being capable of providing improved luxurious sense of projected light. The vehicle lighting fixture can include a housing, an outer lens configured to cover an opening of the housing to define a lighting chamber; and a light source and a light guiding lens located in the lighting chamber. The light guiding lens is configured so as to receive light from the light source and guide the light to a light exiting surface thereof for light projection. The light guiding lens has a functional surface which is opposite to the light exiting surface and can include a plurality of flute cuts configured to diffuse light and a plurality of prism cuts configured to reflect light. The plurality of prism cuts are arranged at random on the functional surface.

Some conventionally known vehicle lighting fixtures used as a rear lamp or a position lamp include a light source such as a light emitting diode (LED) and a light guiding lens having a reflective function portion and a light exiting surface. In this type of lighting fixtures, light emitted from the light source can enter the light guiding lens and be guided by the reflective function portion thereof in its longitudinal direction. During the guiding of light, the light can be reflected, thereby exiting through the light exiting surface. In this case, there may be formed a plurality of lens cuts in a surface of the light guiding lens opposite to the light exiting surface.
In a vehicle lighting fixture including such a light guiding lens, there is a large difference in luminance between a nearer position and a farther position from the light source, resulting in decreased uniform luminance in the light exiting surface.
In order to cope with this problem, there has been proposed a vehicle lighting fixture including a light guiding lens as shown in FIG. 1, for example, those disclosed in Japanese Patent Application Laid-Open No. 2013-045671.
FIG. 1 is a cross-sectional view illustrating part of a light guiding lens 101 of the vehicle lighting fixture proposed in Japanese Patent Application Laid-Open No. 2013-045671. The light guiding lens 101 is configured to include a plurality of prism cuts 101a formed in a surface (lower surface in FIG. 1) opposite to a light exiting surface (upper surface in FIG. 1) on a side near a not-illustrated light source and curved surfaces 101b concavely formed between the prism cuts 101a configured such that the respective curved surfaces 101b connect the adjacent ones of the prism cuts 101a.
In the light guiding lens 101 with such a configuration, light from the light source can be diffused by the curved surfaces 101b to reach the farther side of the light guiding lens 101 and be totally reflected within the light guiding lens 101. Then, the light diffused and/or reflected can be controlled by the prism cuts 101a in terms of light distribution so as to be projected through the light exiting surface of the light guiding lens 101 (upper surface in FIG. 1). Accordingly, the difference in luminance between the nearer position and the farther position from the light source can be reduced to improve the uniformity in luminance in the observed light exiting surface of the vehicle lighting fixture. The formation of such curved surfaces 101b concavely formed between the adjacent prism cuts 101a can properly diffuse the bundle of light rays to provide a light projection state with even luminance.
In the vehicle lighting fixture including the light guiding lens 101 as illustrated in FIG. 1, although the difference in luminance between the nearer position and the farther position from the light source can be reduced, the light projection is monotonous due to the uniform projection of light with a wider angle range of the light guiding lens 101, resulting in decrease of luxurious feeling as a vehicle lighting fixture.


Provided is a computer system including at least one host computer; and at least one storage system, characterized in that: the storage system has a disk drive and a disk controller, and provides a storage area of the disk drive as at least one logical unit; upon detecting a failure in a logical path serving as an access route from the host computer to the logical unit, the host computer specifies logical paths for accessing the same logical unit that is connected to the logical path where the failure is detected; the host computer executes failure detecting processing for the specified logical paths to judge whether the specified logical paths are normal or not; the host computer selects normal logical paths out of the specified logical paths; and the host computer accesses the logical unit via the normal logical paths selected.

This invention relates to a computer system having a host computer and a storage system. More specifically, this invention relates to a technique of switching logical paths that connect a host computer and a storage system.
There have been known multi-path computer systems in SAN (Storage Area Network) environments. A multi-path computer system has a storage system and a host computer, which are connected to each other by a SAN containing a Fibre Channel switch.
A storage system in a multi-path computer system provides a logical unit, which is connected to a host computer via a plurality of logical paths. The logical paths are paths provided for redundancy in accordance with combinations of physical paths along communication routes between a host computer and a storage system. The physical paths are I/O paths connecting the host computer and the storage system to each other. The I/O paths are, for example, SCSI cables or Fibre cables.
Generally speaking, a plurality of logical paths pass common components. Accordingly, when a failure is detected in one logical path, there is a strong possibility that other logical paths are also experiencing a failure. In the case of a failure in a Fibre Channel switch, for example, every logical path that passes this Fibre Channel switch suffers a failure.
A host computer in a multi-path computer system needs to choose which logical path is to be used for transmission of an I/O request to a logical unit set in a storage system.
A technique of selecting a logical path by round robin is disclosed in JP 2004-185093 A. According to this technique, the host computer chooses a logical path by round robin and uses the chosen logical path in sending the I/O request.

This patent is subject to a terminal disclaimer.

Computer system and method for performing failure detecting processing for a logical path


A method used for an induction type power supply system, for detecting whether an intruding metal exists in a power transmission range of the induction type power supply system, includes interrupting at least one driving signal of the induction type power supply system to stop driving a supplying-end coil of the induction type power supply system; obtaining a first attenuation slope during a first period when driving of the supplying-end coil is stopped, and obtaining a second attenuation slope during a second period when driving of the supplying-end coil is stopped; and determining whether the intruding metal exists in the power transmission range of the induction type power supply system according to the first attenuation slope and the second attenuation slope.

1. Field of the Invention
The present invention relates to a method used for an induction type power supply system, and more particularly, to a method of detecting whether there is an intruding metal existing in a power transmission range of an induction type power supply system.
2. Description of the Prior Art
An induction type power supply system includes a power supplying terminal and a power receiving terminal. The power supplying terminal applies a driver circuit to drive a supplying-end coil to generate resonance, in order to send electromagnetic waves. A coil of the power receiving terminal may receive the electromagnetic waves and perform power conversion to generate DC power to be supplied for a device in the power receiving terminal. In general, both sides of the coil are capable of transmitting and receiving electromagnetic waves; hence, a magnetic material is always disposed on the non-induction side of the coil, allowing the electromagnetic energy to be aggregated on the induction side. The magnetic material close to the coil may enlarge the coil inductance, and thereby increase the electromagnetic induction capability. In addition, the electromagnetic energy exerted on a metal may heat the metal. This principle is similar to an induction cooker. Therefore, another function of the magnetic material is to isolate the electromagnetic energy, in order to prevent the electromagnetic energy from interfering with the operations of the device behind the coil, and also prevent the electromagnetic energy from heating surrounding metals for safety.
In the induction type power supply system, an induction coil is included in each of the power supplying terminal and the power receiving terminal for sending power energy and control signals. The safety issue should be considered in this system. However, a user may intentionally or unintentionally insert a metal between these induction coils when using the induction type power supply system. If an intruding metal appears during power transmission, the electromagnetic energy generated by the coil may rapidly heat the intruding metal and cause an accident such as burning or exploding. Therefore, the industry pays much attention to this safety issue, and related products should have the capability of detecting whether an intruding metal exists. When there exists an intruding metal, power supply output may be cut off for protection.
In the prior art, a power loss is calculated by measuring the output power of the power supplying terminal and the input power of the power receiving terminal, and existence of the intruding metal is determined based on the calculated power loss and a predetermined threshold value. If the power loss exceeds the threshold value, the system may determine that there is an intruding metal. However, the above method of determining the intruding metal may not achieve satisfactory protection effects. For example, when a smaller intruding metal such as a coin, key or paper clip exists in the power transmission region of the power supplying terminal, the small intruding metal may not be successfully detected by the above method. Also, if the threshold value for determination is too strict, small noise interferences may be wrongly determined to be an intruding metal, which results in unnecessary power cut. Thus, there is a need for improvement over the prior art.

Induction type power supply system and intruding metal detection method thereof


A compact motor arrangement having at least three equi-angularly-spaced motors having coplanar rotational axes intersecting at a common point. Each motor has an exterior shape of a frustrum of a cone, and a conical air gap, the exterior surfaces of adjoining motors being tangential.

The invention relates to a motor arrangement comprising at least three electric motors, each comprising a stator having the form of a hollow, tapering, and substantially rotationally symmetrical body and a rotor, the axes of rotation of the motors being substantially arranged in one and the same plane and being so mutually spaced angularly that adjacent axes of rotation intersect each other in a common intersectional point at angles which are substantially equal to 360.degree. divided by the number of comprised motors. The invention also relates to the use of such motor arrangements as rudder motors in missiles.
Arrangements of this type and comprising four conventional torque motors are previously known. By a conventional motor in this case is meant a motor having a cylindrical rotor and a stator adapted thereto. A motor arrangement consisting of four such conventional motors is relatively bulky because there is a relatively large space in the center of the motor arrangement which is not used. In some applications, for example as rudder motors in missiles etc., the motor arrangement occupies an inadvantageously large part of the space.
Torque motors of the kind set forth have a torque which is linearly dependent on the length of the rotor-stator unit and approximately related to the square of its diameter. In this connection a motor constant K.sub.M may be defined as: ##EQU1## where T.sub.p is the peak torque and P.sub.p peak power input at stall condition.
Electrical motors with a cone-shaped stator per se are previously known (see EP No. A1 0 010 685 FIGS. 13-14 with the corresponding text). However, there are no suggestions in this publication to make the motor exterior concial or to use such motors in a compact motor arrangement comprising more than one motor in a common plane and in an optimal way utilizes an available volume.

Motor arrangement comprising at least three co-planar conical motors


The present invention describes a process for the industrial production of L-carnitine, comprising the enantioselective reduction of an alkyl 4-chloro-3-oxobutyrate or 4-chloro-3-oxobutyramide. The optically active 3-hydroxy derivative thus obtained is reacted with trimethylamine, obtaining crude L-carnitine, which is then finally purified. The catalyst used for the reduction is a complex of ruthenium bound to a penta-atomic bis-heteroaromatic system. The reduction reaction, performed in controlled conditions of hydrogen pressure, substrate concentration, temperature, and substrate: catalyst molar ratio, enables 4-chloro-3-hydoxybutyrate or 4-chloro-hydroxybutyamide to be obtained in a high yield. The process described, which leads to L-carnitine being obtained, is easily applicable on an industrial scale.

The invention described herein relates to the synthesis of L-carnitine.
The subject of the invention is a process for obtaining this product, which can be easily implemented on an industrial scale.
Carnitine contains an asymmetry centre and can therefore exist in the form of two enantiomers, designated R-(xe2x88x92)-carnitine and S-(+)-carnitine, respectively. Of these, only R-(xe2x88x92)-carnitine is present in living organisms where it acts as a carrier for the transport of fatty acids across the mitochondrial membranes.
It is therefore essential that only R-(xe2x88x92)-carnitine be administered to patients undergoing regular haemodialysis treatment or treated for cardiac or lipid metabolism disorders.
In view of the substantial biological and pharmaceutical interest in this molecule, many studies have been conducted with a view to its synthesis.
The known techniques of large-scale synthesis of L-carnitine include:
i) the optical resolution of a racemic mixture: this technique involves the use of a resolving agent in an equimolar amount and the separation of the unwanted enantiomer. This procedure leads to the loss of 50% of the starting product.
ii) Stereospecific hydration of crotonobetaine or xcex3-butyrobetaine by a microbiological method (U.S. Pat. No. 4,708,936). This microbiological synthesis procedure entails the risk of imperfect reproducibility, of possible alterations of the strain used, and of possible biological contamination of the product.
iii) Enantioselective reduction of a butyric 4-chloro-3-oxoester by means of mono- or bimetallic ruthenium catalysts. This yields the corresponding 3-hydroxy derivative which, by reaction with trimethylamine and hydrolysis of the ester group, is converted to L-carnitine.
The reduction reaction mentioned in iii) has been the subject of several studies.
For example, patent EP-B-295109 describes the reduction of a 4-chloro-3-oxobutyrate with a catalyst containing ruthenium bound to a chiral diphosphine which in turn is bound to a bisnaphthalenic system; the valence of the metal is completed by a combination of halogens and triethylamine. The reaction is carried out at 30xc2x0 C. with a hydrogen pressure ranging from 40 to 100 kg/cm2, with substrate:catalyst molar ratio of 1000:1, in a reaction time of 16-20 hours. The optical yield below 67% and the lengthy reaction times and high pressures involved make the process industrially unacceptable.
In patent application EP-A-339764, L-carnitine is obtained by means of a process comprising the reaction of a 4-halo-3-oxobutyrate with the above-mentioned ruthenium-based catalyst: the reaction is carried out at approximately 100xc2x0 C., at a mean pressure of 70-100 kg/cm2, with a substrate:catalyst molar ratio ranging from 1000 to 10,000:1. The process described once again presents the disadvantage of having to operate at high pressure values. In addition, the overall carnitine yield with this method was modest (46%). Similar results are reported in Tetrahedron Letters, 29, 1555, (1988).
The synthesis methods described above not only present modest yields and, in the first case, also lengthy reaction times, but also involve operating at high hydrogen pressures, which increases the cost of the process and the safety precautions to be adopted. This problem becomes crucial when moving over from laboratory- to industrial-scale production.
A number of studies describe the reduction of xcex2-ketoesters by means of ruthenium complexes catalysts, operating at moderate pressure values; the results. however, are unsatisfactory in terms of yields and/or reaction times, and these processes therefore cannot be applied on an industrial scale. In Tetrahedron Letters, 32, 4163, (1991), the reduction of 4-chloro-3-oxobutyrate with 4-atm. hydrogen pressure is described. The reduced product has an enantiomeric purity inferior to that obtained when operating at high pressure, and the reaction times are rather lengthy (6 h). The lower enantiomeric purity leads to a greater loss of L-carnitine yield. In EP-A-573184, the reduction of a terbutylic ester of the same substrate is carried out at a pressure of 10-15 kg/cm2: the reaction is completed in two hours with an unsatisfactory yield and enantiomeric purity.
Analysis of the above-mentioned technique reveals the lack of a process for the synthesis of L-carnitine which is easily and efficiently reproducible on an industrial scale. In particular, what is lacking is an L-carnitine synthesis process comprising the enantioselective catalytic reduction of 4-halo-3-oxobutyric derivatives of such a nature as to be carried out on an industrial scale with high yields and high enantiomeric purity and operating in moderate pressure conditions.
The present invention discloses a process for the industrial production of L-carnitine, comprising the enantioselective reduction of an alkyl 4-chloro-3-oxbutyrate or 4-chloro-3-oxobutyramide. The optically active 3-hydroxy derivative thus obtained is reacted with trimethylamine, obtaining crude L-carnitine, which is then finally purified. The catalyst used for the reduction is a complex of ruthenium bound to a penta-atomic bis-heteroaromatic system. The reduction reaction, performed in controled conditions of hydrogen pressure, substrate concentration, temperature, and substrate:catalyst molar ratio, enables 4-chloro-3-hydroxybutyrate or 4-chloro-hydroxybutyramide to be obtained in a high yeild. The process described, which leads to L-carnitine being obtained, is easily appilcable on an industrial scale.
The subject of the invention described herein is a process for the synthesis of L-carnitine. The first step in achieving the object of the invention consists in the enantioselective catalytic reduction of an alkyl 4-chloro-3-oxobutyrate or 4-chloro-3-oxobutyramide, according to the following diagram:
where:
Yxe2x95x90OR1, NHxe2x80x94R1, N(R1R2) in which R1 is H or
R1,R2, equal or different=alkyl C1-C10 alkylaryl and reaction of formula (II) derivatives with trimethylamine, with formation of L-carnitine.
The preferred starting substrate is ethyl 4-chloro-3-oxobutyrate (ethyl xcex3-chloro-acetoacetate).
The reduction reaction catalyst consists of a ruthenium complex bound to a penta-atomic bis-heteroaromatic system. This structure corresponds to one of the two formulas (III) or (IV).
where:
A=S, O, NR3, N-aryl, Nxe2x80x94COxe2x80x94R3
R3=alkyl C1-C10, alkylaryl, aryl
Q=alkyl C1-C4, phenyl
R, Rxe2x80x2, equal or different=optionally alkyl-substituted phenyl, C1-C6 alkyl, C3-C8 cycloalkyl, or R and Rxe2x80x2 together form a 4-6 atom phosphorocyclic system
X and L, equal or different, have the following meanings:
X=halogen, alkylsulphonate, arylsulphonate
L=halogen, aryl, xcfx80 aryl, olefin system, xcex73 allyl system, such as, for example, the 2-methylallyl system, carboxylate group, such as, for example, acetate or trifluoroacetate.
What is meant by the xcfx80 aryl group is a type of direct co-ordination with the aromatic electron system, without any direct bonding of a carbon atom of the ring with the metal.
The formula (III) and (IV) compounds are described in patent application WO 96/01831, incorporated herein for reference.
In particular, the preference is for the use of catalysts where A represents S (3,3xe2x80x2-bisthiophenic structure), X represents halogen, particularly iodine, and L is an aryl system. The preferred catalyst is {[Ru (p-cymene) I (+) TMBTP] I}, represented by formula (V).
The reduction of alkyl 4-chloro-3-oxobutyrate or 4-chloro-3-oxobutyramide is done at a hydrogen pressure ranging from 2 to 7 bar, at a temperature ranging from 90 to 150xc2x0 C., and with a substrate:catalyst molar ratio ranging from 5,000:1 to 30,000:1.
According to a preferred realisation of the invention, the reduction is performed at a hydrogen pressure of 5 bar, at a temperature of 120xc2x0 C., and with a substrate:catalyst molar ratio between 10,000:1 and 15,000:1
The concentration of the substrate in the reaction mixture also contributes towards obtaining the reduced product in a high yield and with high-grade optical purity. This concentration ranges from 5 to 15 g of substrate per 100 ml of solvent, and the preferred concentration is 10 g/100 ml.
The reaction mixture may advantageously contain catalytic amounts of a base.
The moderate hydrogen pressure conditions (on average 5 bar) make it possible to operate with simpler reactors and with less stringent safety conditions compared to similar reactions described in the known technique requiring a pressure of 100 atmospheres.
The process described herein proves easily reproducible on an industrial scale and does not require the use of any additional expedients, such as, for example, the use of acid co-catalysts.
The process according to the invention yields optically active alkyl 4-chloro-3-hydroxybutyrate or 4-chloro-3-hydroxybutyramide with a yieldxe2x89xa795% and with e.e. ranging from 95 to 97%. As a result of the transformations described here below, these results make it possible to obtain the L-carnitine end product with an overall yield of 65-70%.
Furthermore, high substrate:catalyst ratios make it possible to operate with low amounts of catalyst, thus contributing to cost savings in the reaction process.
The alkyl 4-chloro-3-hydroxybutyrate or 4-chloro-3-hydroxybutyramide obtained by catalytic reaction are subsequently converted to L-carnitine reaction of formula (II) derivatives by reaction with trimethylamine.
The reduced derivatives are reacted with trimethylamine with formation of L-carnitine alkyl ester or alkyl amide. This reaction is performed preferably at temperatures from 55 to 90xc2x0 C. for time periods ranging from 1 to 70 hours. Particularly satisfactory results are obtainable when operating at 65xc2x0 C. for 60 hours, or at 80xc2x0 C. for 24 hours. According to the type of reactor used, stirring and loading conditions, reaction times of even 1-2 hours have been observed at 80xc2x0 C.
The reaction entails the substitution of the 4-chloro with the 4-trimethylamine group for and hydroylsis of the ester or amide group, with the formation of crude L-carnitine, which is then purified to make it suitable for pharmaceutical use.
The purification can be done with known methods such as, for example, chromatography, extraction with solvents, ultrafiltration, and other equivalent methods.
Thanks to the advantages identified above, such as low pressure, high yields, and high-grade optical purity, and the use of limited amounts of catalyst, the invention described herein makes it possible to produce L-carnitine efficiently and economically in large-scale industrial plant.
The invention is further described by means of the following examples.

Industrial process for the production of L-carnitine

Sigma-Tau Industrie Farmaceutiche Riunite S.p.A.


A substrate for use in a pacing lead having a sintered porous platinized steroid eluting electrode. The substrate has at least one raised surface which provides an advantageous mounting portion for the sintered electrode. In the preferred embodiment the mounting portion is nailhead-shaped. The present invention provides an electrode produced with increased dimensional consistency, mechanical strength and impedance as compared to electrodes having a straight wire substrate. Also disclosed is a method of manufacturing such an electrode.

1. Field of the Invention
This invention relates generally to chronically implanted medical leads and, in particular, to a substrate which provides increased dimensional consistency and impedance as well as simplifying manufacture of a sintered porous platinized steroid eluting electrode used in a pacing cardiac lead.
2. Description of the Prior Art
The safety, efficacy and longevity of an implanted pacemaker system depends, in part, on the performance of the pacing leads, the electronic circuits and the integrity of the pulse generator, and the capacity and reliability of the pulse generator power source. These inter-related components of the implanted pacemaker system optimally are matched in a fashion that accommodates ever increasing demands on the modes of operation and function of the system in conjunction with an overall reduction in system size, an increase in system longevity and an increased expectation in system reliability. During the past thirty years, the technology of cardiac pacing has significantly advanced. Implantable pacing systems offer ever increasing variety of pacing modalities, thereby substantially broadening the indications for pacemaker use. In conjunction with this advancement, there has been extensive research and development expended to optimize the performance of pacing leads and their reliability while concurrently simplifying their manufacture.
In the past ten years, substantial improvements in reliable stable chronic pacemaker sensing and stimulation thresholds have been achieved which in turn have allowed the development of smaller and longer-lived pacemakers that can be used with leads having excellent safety margins and reliability. As new circuits are developed with lower "overhead" current drains, however, and as the circuits increase in complexity to allow for ever increasing pacemaker capabilities in their programmable functions, modes and memory, pacemaker longevity depends increasingly more on the characteristics of the lead. In addition, many doctors who implant pacemakers prefer that pacing lead bodies be made ever thinner, to occupy less space in the venous system, without diminishing or detracting from the mechanical strength and integrity of the lead body.
In the early days of cardiac pacing, pacing leads having relatively very high geometric surface area electrodes were employed with relatively bulky and short-lived pulse generators. Early investigators, including Dr. Victor Parsonnet, advanced designs of pacing lead electrodes for achievement of low polarization and low thresholds while presenting a relatively small effective surface area for the delivery of a stimulating impulse in designs known as a differential current density (DCD) electrode of the type shown in U.S. Pat. No. 3,476,116. The DCD electrode (like all pacing electrodes of the time) suffered unacceptable chronic tissue inflammation and instability in clinical testing and was not commercialized.
Subsequent researchers, including Dr. Werner Irnich, explored in considerable detail the electrode-tissue interface and sought to arrive at an optimum exposed electrode surface area for both stimulation thresholds and sensing. In his work "Considerations in Electrode Design for Permanent Pacing" published in Cardiac Pacing; Proceedings of the Fourth International Symposium of Cardiac Pacing (H. J. Thalen, Ed.) 1973, pp. 268-274, Dr. Irnich argued that the field strength (E) required to stimulate cardiac tissue varies according to the following equation: ##EQU1## where v equals applied voltage (threshold, v), r equals electrode radius and d equals fibrous capsule thickness. Dr. Irnich further argued the mean value for d equals about 0.7 mm, regardless of electrode radius. Therefore, the smaller the electrode radius, the lower the threshold (assuming E is a constant) until r equals d. When r<d, thresholds rise again. Dr. Irnich concluded the exposed hemispherical electrode at the tip of the lead should have a radius in the order of 0.7 to 1.0 mm which would result in an exposed surface area of 3-6 mm.sup.2. However, Dr. Irnich went on in his article to propose a design employing wire hooks designed to penetrate the myocardium to hold the electrode in position. These active fixation wire hook electrodes never achieved popularity and were supplanted by passive fixation tined and active fixation screw-in endocardial pacing leads.
In a later paper, "Acute Voltage, Charge and Energy Thresholds as Functions of Electrode Size for Electrical Stimulation of the Canine Heart", by F. W. Lindemarts and A. N. E. Zimmerman; Cardiovascular Research, Vol. XIII, No. 7, pp. 383-391, July 1979, the authors demonstrated an electrode radius of about 0.5 mm is optimal in the acute situation. However, it was recognized the benefits of a small electrode surface area would be lost when the fibrous capsule gets thicker than about 0.5 mm (as Dr. Irnich also stated.) For that reason electrodes of such small surface area, the authors concluded, could not be used chronically.
Dr. Seymour Furman also studied the relationship of electrode size and efficiency of cardiac stimulation and presented a-ball-tip/exposed spaced coil electrode and a small hemispheric electrode in his article entitled "Decreasing Electrode Size and Increasing Efficiency of Cardiac Stimulation" in Journal of Surgical Research, Vol. 11, No. 3, March 1971, pp. 105-110. Dr. Furman concluded the practical lower limit of electrode surface area was in the range of 8 mm.sup.2, observing that impedance increased as an inverse function of the surface area.
Electrodes of many shapes including cylindrical, ball-tip, corkscrew, ring tip and open cage or "bird cage" configurations were pursued with exposed electrode surface areas tending toward 8 mm.sup.2 in the mid-1970's.
More recently, various investigators have emphasized materials and their relationship to the considerations involved in optimizing electrode design. For example, Bornzin, U.S. Pat. No. 4,502,492 owned by Medtronic, Inc. discloses a low polarization, low threshold electrode design which was commercialized as the TARGET TIP.RTM. lead during the early to mid-1980's. That design featured a generally hemispherical electrode with circular grooves, fabricated from platinum and coated over its external surface with a plating of platinum black. This combination of the relatively low (8 mm.sup.2) macroscopic electrode surface area and relatively high microscopic electrode surface area (due to the use of platinum black-) contributed to the achievement of state-of-the-art thresholds for that time period. Other manufacturers marketed electrodes of other materials and configurations including totally porous platinum mesh (Cardiac Pacemakers, Inc.), porous surface sintered (Cordis Corporation), glassy and vitreous carbons (Siemens Inc.), and laser drilled metal (Telectronics Ltd.) electrodes in that same time period.
A considerable breakthrough in the development of low threshold electrode technology occurred with the invention of the steroid eluting porous pacing electrode of Stokes, U.S. Pat. No. 4,506,680 and related Medtronic U.S. Pat. Nos. 4,577,642; 4,606,118 and 4,711,251, all incorporated herein by reference. The electrode disclosed in the Stokes '680 patent was constructed of porous, sintered platinum or titanium, although carbon and ceramic compositions were also mentioned. Proximate the electrode a plug of silicone rubber impregnated with the sodium salt of dexamethasone phosphate, or a water soluble form of other glucocorticosteroids, was placed. The silicone rubber plug allowed the release of the steroid through the interstitial gaps in the porous sintered metal electrode to reach the electrode-tissue interface and prevent or reduce inflammation, irritability and subsequent excessive fibrosis of the tissue adjacent to the electrode itself. The porous steroid eluting electrode presented a sensing (source) impedance substantially lower compared to similarly sized solid electrodes and presented significantly lower peak and chronic pacing thresholds than similarly sized solid or porous electrodes. These two advantages of the steroid eluting electrode allowed a relatively small surface area electrode of about 5.5 mm.sup.2 (CAPSURE.RTM. SP Model 5023, 5523 leads sold by Medtronic, Inc.) to raise lead impedance without sacrificing the ability to sense heart activity. The smaller electrode size was important because it resulted in higher current density during stimulation pulses. This, in turn, was important because it provided more efficient stimulation of the heart tissue with lower current drain from the implanted pacemaker power source. This resulted in overall increased longevity of the implanted pacemaker system.
Lead impedance is a function of the resistance of the lead conductor and the stimulating electrode as well as the effective impedance of the electrode-tissue interface. An inefficient way or means to raise impedance is to increase the resistance of the lead conductor. This wastes current as heat. It is preferable to decrease lead current drain with more efficient control of the stimulating electrode-tissue interface impedance. This can be done by reducing the geometric surface area of the electrode. It has been widely believed that small electrodes, however, are inefficient at sensing natural depolarizations of the cardiac tissue. This is not necessarily true. The amplitude of the intrinsic cardiac depolarization signals typically the ventricular QRS and/or atrial P-wave complexes) is essentially independent of electrode size. The problem of sensing natural depolarizations therefore is that the sense amplifiers of some pulse generators have comparatively lower input impedance, some as low as 20 k.OMEGA., with typical values of about 80-100 k.OMEGA.. The impedance of the QRS or P-wave signal (or "source impedance") increases as the electrode surface area decreases. Thus, a 5 mm.sup.2 polished electrode will produce QRS or P-waves with about 2.5-5 k.OMEGA. source impedance (depending on the material). According to Kirchoff's law, the attenuation of the signal in the generator's amplifier is 1/(1+Z.sub.in /Z.sub.s) where Z.sub.in is the input impedance of the amplifier and Z.sub.s, is the source impedance of the signal to be sensed. Thus, for a signal with a 5 k.OMEGA. source impedance into an amplifier with a 20 k.OMEGA. input impedance will have its amplitude reduced by [1/ (1+20/5)].times.100=20%. In marginal cases, this may make the difference between being able or not being able to sense properly. Therefore, it is important to keep the source impedance low, preferable to attenuate less than 10% of the cardiac input signal, that is, Z.sub.s <2222.OMEGA., for a 20 k.OMEGA. amplifier.
Thus, there is a trade-off with geometric surface area of the electrode between the demands for low current drain and adequate sensing. In addition, it is desirable to achieve relatively low polarization effects to avoid distortion of the electrogram of evoked or intrinsic cardiac depolarizations or leave a postpulse potential of sufficient magnitude to be mistakenly sensed as a QRS or P-wave by the amplifier.
Recent advances in lead design have continued decreasing the exposed geometric surface area of the electrode. One such example is disclosed in U.S. patent application Ser. No. 07/887,560 filed May 18, 1992, now U.S. Pat. No. 5,282,844 and entitled "High Impedance, Low Polarization, Low Threshold Miniature Steroid Eluting Pacing Lead Electrodes" incorporated herein by reference. That application discloses a lead featuring a porous platinized steroid eluting electrode exhibiting an effective surface area in the range of 0.1 to 4.0 mm.sup.2, and preferably between 0.6 to 3.0 mm.sup.2. Such small electrodes, while having many desirable qualities, are relatively more difficult to consistently manufacture, especially with respect to electrode diameter and concentric dimension.
Porous platinized steroid eluting electrodes have been manufactured using a slurry process. Specifically a slurry of platinum particles suspended in a liquid organic binding agent is created. To form the electrode, a substrate, typically a straight shank of wire, is dipped at one end into the slurry. A portion of the platinum mixture sticks to the wire substrate when it is removed. The substrate is then sintered to drive off the binder and fuse the platinum particles together. Under conditions of mass production the resultant electrode is many times, however, dimensionally inconsistent, e.g. eccentric, too large or too small and thus unacceptable.


A directional speaker and a display apparatus having the same are provided. In particular, the display apparatus includes a pair of directional speakers as a surround sound speaker, wherein each directional speaker includes a driver to generate sound and a guide tube provided with sound radiated holes linearly aligned on one surface thereof.

1. Field
Apparatuses and methods consistent with one or more exemplary embodiments relate to a directional speaker and a display apparatus including the directional speaker as a surround sound speaker.
2. Description of the Related Art
A display apparatus is an apparatus that displays a screen by receiving image signals. Examples of a display apparatus include a television, a monitor, and the like.
A display apparatus includes a display unit configured to display a screen and a stand configured to support the display unit. Speakers that output sounds are arranged in the display unit.
Speakers include front speakers disposed at lower portions of the display unit and allowing viewers in front of the display apparatus to receive audio from the front and surround sound speakers disposed at rear portions of the display unit opposite to each other and allowing the viewers to receive audio from both sides of the front.
In recent years, a thickness of a display unit has been reduced for better design. However, there is a limit to the reduction of thickness since the display units accommodate the speakers or printed circuit boards (PCBs) to control the operation of display apparatuses.
Thus, related art display apparatuses having a display unit that appears slim have been developed by increasing a thickness of a central portion of the display unit to accommodate speakers and PCBs while decreasing thicknesses of both side edges.

Directional speaker and display apparatus having the same


A holster incorporating a spring locking member which engages a portion of a handgun to provide a physical restraint upon the holstering or drawing of the handgun to prevent inadvertent removal of the weapon or accidental loss of the handgun when the user is in strenuous movement. The spring locking member includes a leaf spring secured to the body of the holster at one end carrying at its other end a protruding head having tapered surfaces which will enter and obstruct a portion of the trigger guard region. The protruding head is not of sufficient size to contact the trigger when the handgun is fully home e.g. bottomed out in the holster. The spring member has sufficient resistance to deflection such that the weight of the handgun plus any acceleration due to strenuous activity of the user is insufficient to cause the weapon to be dislodged. The resistance to bending of the spring member however is selectd so that the normal or slightly increased withdrawal pressure by the user's hand on the gun butt is sufficient to deflect the spring and protuding head and to allow the hand gun to be removed without the use of the trigger finger.

There has for a number of years been a recognized need for a holster which includes a locking member to prevent unauthorized removal of the hand gun by a suspect or other person when the holster is being worn by a law enforcement officer. The need for such holsters has been met by a front opening holster with a locking mechanism disclosed in the U.S. Pat. Nos. 3,749,293, 3,960,460, 3,997,583, and 4,035,902 of these inventors. Such locking mechanisms cooperate with a front opening design so that the handgun is blocked from removal upwards and is removed in a forward direction.
We have discovered however that there is a need for a lock or latch mechanism for a top opening and top removal holster designed not to prevent removal from the top of the weapon but to prevent the weapon from falling out in strenuous activities. This need has become more noticeable with the present trend towards open top or non-flap holsters for use by law enforcement officers. There has been at least one attempt in the past to place a trigger locking device within the trigger guard and that is found in a U.S. patent of approximately 50 years ago. It has been found however that devices of that type which require the user to insert his finger into the trigger guard adjacent to the trigger prior to drawing are dangerous. Inherent in the design is the situation that upward movement of the officer's hand causes his trigger finger to engage the trigger. If the weapon is cocked in a non-safety condition there is a serious danger of discharging in the holster. For this reason the prior devices of the type just described have not met with acceptance or success.


A densitometer apparatus is disclosed which is adapted for accurately measuring the density of a liquid and particularly of a slurry flowing in a pipeline. The apparatus includes a pipe section which is coupled to the rest of the pipeline by substantially friction and resistance free hydrostatic bearings in such a manner that the pipe section is able to move, at least to a limited extent, in a direction parallel with the earth's gravitational field. The weight of the pipe section is accurately measured together with the weight of the slurry or liquid contained therein by load cells, strain gauges or the like. A unique flow velocity meter is also disclosed. The flow velocity meter includes two densitometers positioned at a predetermined distance from one another on the pipeline, and measures the time it takes a density fluctuation pattern to travel from one densitometer to another.

1. Field of the Invention
The present invention is directed to an apparatus for accurately measuring the weight of a fluid flowing through a pipeline, and more particularly to an apparatus for accurately measuring the varying density of a slurry flowing through a pipeline. The present invention is also directed to an apparatus capable of measuring the flow velocity of a slurry flowing through a pipeline.
2. Brief Description of the Prior Art
Pipelines capable of transporting coal and various other mined minerals such as iron ore, in the form of a thick aqueous slurry have been known for a long time. These pipelines, particularly coal slurry pipelines, are presently gaining increasing importance in view of the world's increasing reliance on coal as a major energy source.
Such slurry pipelines for coal and other minerals vary greatly in length and diameter. The particulate size of the slurried coal or other solid mineral may also vary depending on the purpose and particular application of the transporting pipeline. In some instances the slurry predominantly contains rather fine particulate matter, while in some others the slurry may include relatively large, "chunk" sized particles. In case of coal slurry pipelines, the slurry may contain as much as 50% solid material by volume. As it is well known in the prior art, the density of slurries having rather large solid particles is usually not uniform throughout any cross-section of the pipeline; rather the heavier particles are settled toward the bottom of the pipeline. Furthermore, the average density of the slurry passing through any given cross section of the pipeline often varies as a function of time.
In light of the above, it has become standard practice in the art to determine the amount of coal or other solid mineral passing through any given point on the pipeline by measuring and monitoring the average density of the slurry as a function of time. This is accomplished in the prior art either by use of nuclear densitometers or by devices which measure the weight of a given pipe section containing the slurry flowing therethrough. Both nuclear densitometers and the weight measuring type densitometers, however, suffer from certain inherent shortcomings.
Nuclear densitometers work rather poorly when the density of the slurry is not uniform throughout the cross section of the pipe. The prior art weight measuring type densitometers on the other hand, are, generally speaking, unable to accurately determine the true weight of a given pipe section because of the inherent structural problem that the pipe section must be physically coupled to the pipeline. Various types of flexible joints were used for this purpose in the prior art, and such prior art density or weight measuring devices are described in U.S. Pat. Nos. 3,503,267; 3,320,791; 688,388; 2,039,997; 2,613,530; 2,669,118; 3,812,723; 3,143,887 and 1,905,558.
The joints of these prior art devices, however, negatively affect the accuracy of the measured weights and densities because of their usually nonlinear bending stiffness. The above cited patents indicate that significant effort was devoted in the prior art to increase the accuracy of weight measuring type densitometers, and that, in spite of this effort, truly accurate measurements have, up to the present, not been possible.

Apparatus for measuring varying density of a slurry flowing in a pipeline


Circuits, methods, and apparatus that may allow an electronic device to control a power adapter. One example may provide an electronic system where an electronic device may control a power adapter through a communication channel. Data transferred in the communication channel may include the temperature of the power adapter, the charging capability of the adapter, and other types of data. In one example, power and data may share the same two wires, and the power and data may be time-division multiplexed. That is, the two wires may convey power and data at different times. Another example may include circuitry to detect a connection between the electronic device and the power adapter. Once a connection is detected, power may be transferred from the power adapter to the electronic device. This power transfer may be interrupted on occasion to transfer data between the power adapter to the electronic device.

The number and types of electronic devices available to consumers has increased tremendously the past few years, and that rate of increase shows no signs of abating any time soon. These electronic devices include portable devices, such as laptop, netbook, or tablet computers, cell, media, or smart phones, global positioning devices, media players, and other such devices.
These portable devices need to be supplied power during operation, and this power may come from external sources or internal sources, such as batteries. These batteries typically need to be charged using an external source, such as a power adapter. These power adapters may receive AC power from a wall outlet, car charger, or other source, and provide DC power that may be used to charge batteries.
But some devices, such as laptop computers, are very computationally powerful, and therefore require a fair amount of power. Complicating this further is the fact that users of these laptops want to be able to run their laptops for extended periods of time without having to recharge the batteries. Moreover, when a user does connect to a power source to charge the batteries, it is likely the user wants to have the batteries charge very quickly so that the user is free to disconnect from the power source.
For these reasons, many newer electronic devices have relatively large batteries. Accordingly, it has become desirable to be able to provide large amounts of charging power very quickly.
But this quick charging is not without its drawbacks. For example, this quick charging may cause high temperatures in a power adapter. To cool the power adapter, the power adapter may need to be made fairly large, such that heat may be dissipated. To avoid this, it may be desirable for an electronic device to control or adjust the power adapter in order to maintain the temperature of the power adapter.
Thus, what is needed are circuits, methods, and apparatus that allow an electronic device to control a power adapter.

Time-domain multiplexing of power and data


A dynamic range and contrast modification method for electronic images, and digital and analogue implementations are disclosed. Dynamic range changes are accomplished by making linear and nonlinear modifications to the low frequency component. Contrast changes are accomplished by making cross dependent, linear, and nonlinear modifications to the high frequency component. Cross dependent modifications are modifications that depend upon the changes to the low frequency component. Modifications are achieved using processor elements that implement mathematical operations. An automatic gain control, AGC, is used to control the low frequency component modification for some embodiments.

Many electronic images such as news and sporting events are taken under uncontrolled lighting conditions. Thus image dynamic range and contrast may be less than aesthetically pleasing. On the other hand, medical images such as fluoroscopic videos may contain such poor contrast and dynamic range so as to limit their value. These and other electronic imaging conditions need to be addressed in a timely and cost effective manner.
A wide variety of techniques and systems have been devised for the processing of electronic image signals with less than ideal dynamic range and/or contrast. A large number of systems are based first upon the analysis of the image using a histogram. Then based upon this analysis the image is modified under operator control. Some techniques consist primarily of simple gray scale modification. On the other hand, some techniques are more sophisticated such as the system set forth in U.S. Pat. No. 5,012,333 to Lee et al. Most of these techniques depend upon a relatively slow computer to perform signal processing. In general these techniques are effective in image improvement, but they can be relatively time consuming especially in the derivation of the histogram. When many frames of electronic images such as live sports, news events, or fluoroscopic images are required to be processed at real time or close to real time most techniques are too time consuming. Faster computers could be employed for signal processing, but this usually increases the cost substantially.
The text Digital Signal Processing by Alan V. Oppenheim and Ronald W. Schafer, Prentice-Hall, 1975 in the chapter titled Homomorphic Signal Processing teaches that some classes of images can be improved with signal processing without extensive analysis of a histogram. The author states that observed images are formed by a multiplying of pattern illumination by pattern reflectance to produce the brightness image. The author also, states that these components of the brightness image can be separated as a function of frequency content. That is to say, in general the illumination component is in a different frequency range than the reflectance component. The author concludes that in general within an electronic image illumination is a low frequency signal and reflectance is a high frequency signal.
The author's signal processing gave image improvement, but addresses only a very limited number of image problems. Therefore, if one could implement a system that could be used to improve a larger variety of image dynamic range and contrast type problems in a timely manner using adjustable hardware, this would be desirable.

Method for electronic image dynamic range and contrast modification