A multi-layer article is disclosed. The article contains a base layer that contains at least one thermoplastic resin and a second layer containing a thermoplastic (co)polyformal superimposed over the base layer. The (co)polyformal conforms to formulae (1a) or (1b),

Multi-wall sheets are generally provided, for example, with a coextrusion layer or layers that contain UV absorbers on one or both its surfaces to protect them from damage (e.g. yellowing) by UV light. Other multi-layer products may also be protected in this way from damage by UV light.
The relevant art concerning multi-layer products is summarised below:
EP-A 0 110 221 discloses sheets of two layers of polycarbonate, wherein one layer contains at least 3 wt. % of a UV absorber. These sheets can be produced according to EP-A 0 110 221 by coextrusion.
EP-A 0 320 632 discloses molded articles of two layers of thermoplastic material, preferably polycarbonate, wherein one layer contains specially substituted benzotriazols as UV absorbers. EP-A 0 320 632 also discloses the production of these molded articles by coextrusion.
EP-A 0 247 480 discloses multi-layer sheets in which a layer of branched polycarbonate is present in addition to a layer of thermoplastic material, wherein the layer of polycarbonate contains specially substituted benzotriazols as UV absorbers. The production of these sheets by coextrusion is also disclosed.
EP-A 0 500 496 discloses polymer compositions, which are stabilised against UV light by means of special triazines and their use as an outer layer in multi-layer systems. Polycarbonate, polyester, polyamide, polyacetals, polyphenylene oxide and polyphenylene sulfide are named as polymers.
However, products known thus far are not completely satisfactory particularly with regard to long-term resistance to UV light (UV-stability).
According to the prior art, water bottles, such as e.g. 5-gallon bottles, do not have a multilayer construction (DE 19943642, DE 19943643, EP-A 0411433). The same applies to reusable milk bottles or baby bottles.
Polycarbonate containers are produced for example by extrusion blow moulding or injection blow moulding.
In extrusion blow moulding the granules are generally melted with a single-screw extruder and moulded through a die to form a free-standing parison, which is then enclosed by a blow mould which pinches the parison together at the lower end. Inside the mould the parison is inflated to give the parison the desired shape. After a cooling period the mould is opened and the blow moulded article can be removed (described in more detail e.g. in Brinkschröder, F. J. "Polycarbonate" in Becker, Braun, Kunststoff-Handbuch, Volume 3/1, Polycarbonate, Polyacetale, Polyester, Celluloseester, Carl Hanser Verlag, Munich, Vienna 1992, pages 257 to 264).
For extrusion blow moulding it is advantageous to use a highly pseudoplastic polycarbonate in order to obtain a high melt stability. Branched polycarbonates are particularly pseudoplastic.
Injection blow moulding is a combination of injection moulding and blow moulding.
The process takes place in three steps:                1) Injection moulding of the parison in the plastic temperature range of the polycarbonate        2) Inflation of the parison in the thermoplastic range of the polycarbonate (the core of the injection mould is also the blowing mandrel)        3) Stripping the blow moulded article and optionally cooling the blowing mandrel with air(described in more detail e.g. in Anders, S., Kaminski, A., Kappenstein, R., "Polycarbonate" in Becker/Braun, Kunststoff-Handbuch, Volume 3/1, Polycarbonate, Polyacetale, Polyester, Celluloseester, Carl Hanser Verlag, Munich, Vienna 1992, pages 223 to 225).
However, none of the products known from the prior art achieves satisfactory results in every respect, particularly as far as long-term stability in relation to hydrolysis is concerned. Water damages polycarbonate above 60° C. Extended contact with boiling water leads to molecular weight reduction, which is further accelerated in the presence of heat stabilisers such as organic phosphites. In addition, polycarbonates can be preferably alkaline-hydrolysed. Microwave radiation further accelerates this degradation.
In patents of the prior art no mention is ever made of hydrolysis protection layers to overcome this disadvantage.
Starting from the prior art the object was therefore to provide a multilayer sheet or coated containers such as e.g. water bottles or medical articles, which should be able to be sterilised in superheated steam, which display improved properties in comparison to the prior art, such as improved long-term stability in relation to hydrolysis in water, even at elevated temperatures, and in the acid and also the basic environment.
This object underlies the present invention.
This object is surprisingly achieved by coatings containing certain polyformals or copolyformals as the polymer basis.
The object is therefore to provide a multi-layer sheet having improved properties including improved long-term UV stability, thermal-ageing properties and resistance to hydrolysis.
This object is achieved surprisingly by protective layer which contains certain polyformals or copolyformals.
The products thus protected are surprisingly superior in terms of UV resistance and in particular with regard to resistance to hydrolysis.
This is particularly surprising, as the polyformals can be considered full acetals, which, according to the current doctrinal opinion of the person skilled in the art, are highly susceptible to hydrolysis, at least in an acid environment. However, in contrast to this, the coatings of polyformals are hydrolysis-stable even towards acid solutions and remain so even at higher temperatures.
The present invention thus provides a protective layer that contain polyformals or copolyformals of the general formulae (1a) and/or (1b),
in which the groups O-D-O and O-E-O stand for any diphenolate groups, in which -D- and -E- are aromatic groups having 6 to 40 carbon atoms, preferably C6 to C12 carbon atoms, which may contain one or more aromatic or condensed aromatic nuclei, optionally containing heteroatoms, and optionally include C1-C12-alkyl groups or halogen substituents and may contain aliphatic groups, cycloaliphatic groups, aromatic nuclei or heteroatoms as bridging links and in which k stands for a whole number from 1 to 1500, preferably from 2 to 1000, particularly preferably from 2 to 700 and most particularly preferably from 5 to 500 and in particular from 5 to 300, o stands for numbers from 1 to 1500, preferably from 1 to 1000, particularly preferably from 1 to 700 and most particularly preferably from 1 to 500 and in particular from 1 to 300, and m stands for a fractional number z/o and n for a fractional number (o-z)/o, wherein z stands for numbers from 0 to o.

Preferred structural elements of the polyformals and copolyformals according to the invention are derived from general structures of the formulae (2a), (2b), (2c) and (2d), wherein the brackets describe the diphenolate groups according to D und E as mentioned for formulae (1a) and (1b), in which R1 and R2, independently of each other, stand for H, linear or branched C1-C18-alkyl- or alkoxy groups, halogen such as Cl or Br or for an optionally substituted aryl- or aralkyl group, preferably for H or linear or branched C1-C12-alkyl-, particularly preferably for H or C1-C8-alkyl groups and most particularly preferably for H or methyl, X stands for a single bond, a C1-C6-alkylene-, C2- to C5-alkylidene, C5-C6-cycloalkylidene group, which may be substituted with C1-C6-alkyl, preferably methyl- or ethyl groups, or a C6- to C12-arylene group, which may optionally be condensed with further aromatic rings containing heteroatoms, wherein p stands for a whole number from 1 to 1500, preferably from 2 to 1000, particularly preferably from 2 to 700 and most particularly preferably from 5 to 500 and in particular from 5 to 300, p stands for numbers from 1 to 1500, preferably from 1 to 1000, particularly preferably from 1 to 700, most particularly preferably from 1 to 500 and in particular from 1 to 300 and q stands for a fractional number z/p and r for a fractional number (p-z)/p, wherein z stands for numbers from 0 to p.
The polyformals or copolyformals can thus be linear or branched.
The bisphenolate groups in formulae (1) and (2) are derived particularly preferably from the suitable bisphenols named below.
Examples of the bisphenols that form the basis of the general formula (1) are hydroquinone, resorcinol, dihydroxybiphenyls, bis-(hydroxyphenyl)-alkanes, bis-(hydroxyphenyl)-cycloalkanes, bis-(hydroxyphenyl)-sulfides, bis-(hydroxy-phenyl)-ethers, bis-(hydroxyphenyl)-ketones, bis-(hydroxyphenyl)-sulfones, bis-(hydroxyphenyl)-sulfoxides, α,α′-bis-(hydroxyphenyl)-diisopropyl benzenes, as well as their core-alkylated and core-halogenated compounds, and also α,ω-bis-(hydroxyphenyl)-polysiloxanes.
Preferred bisphenols are for example 4,4′-dihydroxybiphenyl (DOD), 2,2-bis-(4-hydroxyphenyl)-propane (bisphenol A), 1,1-bis-(4-hydroxyphenyl)-3,3,5-trimethyl cyclohexane (bisphenol TMC), 1,1-bis-(4-hydroxyphenyl)-cyclohexane, 2,4-bis-(4-hydroxyphenyl)-2-methyl butane, 1,1-bis-(4-hydroxyphenyl)-1-phenyl ethane, 1,4-bis[2-(4-hydroxyphenyl)2-propyl]benzene, 1,3-bis[2-(4-hydroxy-phenyl)-2-propyl]-benzene (bisphenol M), 2,2-bis-(3-methyl-4-hydroxy-phenyl)-propane, 2,2-bis-(3-chloro-4-hydroxyphenyl)-propane, bis-(3,5-dimethyl-4-hydroxyphenyl)-methane, 2,2-bis-(3,5-dimethyl-4-hydroxyphenyl)-propane, bis-(3,5-dimethyl-4-hydroxyphenyl)-sulfone, 2,4-bis-(3,5-dimethyl-4-hydroxy-phenyl)-2-methylbutane, 2,2-bis-(3,5-dichloro-4-hydroxyphenyl)-propane and 2,2-bis-(3,5-dibromo-4-hydroxyphenyl)-propane.
Particularly preferred bisphenols are, for example, 2,2-bis-(4-hydroxyphenyl)-propane (bisphenol A), 4,4′-dihydroxybiphenyl (DOD), 1,3-bis[2-(4-hydroxy-phenyl)-2-propyl]benzene (bisphenol M), 2,2-bis-(3,5-dimethyl-4-hydroxy-phenyl)-propane, 1,1-bis-(4-hydroxyphenyl)-1-phenyl ethane, 2,2-bis-(3,5-dichloro-4-hydroxyphenyl)-propane, 2,2-bis-(3,5-dibromo-4-hydroxyphenyl)-propane, 1,1-bis-(4-hydroxyphenyl)-cyclohexane and 1,1-bis-(4-hydroxyphenyl)-3,3,5-trimethyl cyclohexane (bisphenol TMC).
Most particularly preferred are 2,2-bis-(4-hydroxyphenyl)-propane (bisphenol A), 4,4′-dihydroxy biphenyl (DOD), 1,3-bis[2-(4-hydroxyphenyl)-2-propyl]-benzene (bisphenol M) and 1,1-bis-(4-hydroxyphenyl)-3,3,5-trimethyl cyclohexane (bisphenol TMC).
The bisphenols can be used both alone or in mixture with each other; both homopolyformals and copolyformals are included. The bisphenols are known from the literature or can be produced by processes known from the literature (see e.g. H. J. Buysch et al., Ullmann's Encyclopedia of Industrial Chemistry, VCH, New York 1991, 5th Ed., Vol. 19, p. 348).
The polyformals according to the invention can be deliberately branched in a controlled manner by the use of small amounts of trifunctional compounds known as branching agents. Some suitable branching agents are: phloroglucinol, 4,6-dimethyl-2,4,6-tri-(4-hydroxyphenyl) heptene-2; 4,6-dimethyl-2,4,6-tri-(4-hydroxyphenyl) heptane; 1,3,5-tri-(4-hydroxyphenyl) benzene; 1,1,1-tri-(4-hydroxyphenyl) ethane; tri-(4-hydroxyphenyl) phenyl methane; 2,2-bis-[4,4-bis-(4-hydroxyphenyl) cyclohexyl]propane; 2,4-bis-(4-hydroxyphenyl isopropyl) phenol; 2,6-bis-(2-hydroxy-5′-methyl benzyl)-4-methyl phenol; 2-(4-hydroxyphenyl)-2-(2,4-dihydroxyphenyl) propane; hexa-(4-(4-hydroxyphenyl isopropyl) phenyl) orthoterephthalic acid ester; tetra-(4-hydroxyphenyl) methane; tetra-(4-(4-hydroxyphenyl isopropyl)phenoxy) methane; α,α,α″-tris-(4-hydroxyphenyl)-1,3,5-triisopropyl benzene; 2,4-dihydroxybenzoic acid; trimesic acid; cyanuric chloride; 3,3-bis-(3-methyl-4-hydroxyphenyl)-2-oxo-2,3-dihydroindole; 1,4-bis-(4′,4″-dihydroxytriphenyl)methyl)benzene and in particular: 1,1,1-tri-(4-hydroxyphenyl)ethane and bis-(3-methyl-4-hydroxyphenyl)-2-oxo-2,3-dihydroindole.
The use of such branching agents leads to corresponding deviations in formulae (1) and (2) from their idealised structure. This means that according to the amount of branching agent used, structural units having three binding units, which can also be formed as ester functions, etc., depending on the branching agent used, are produced which are derived from the branching agents used.
The 0.05 to 2 mol % of branching agents or mixtures of branching agents that can optionally be incorporated, relative to diphenols used, can be added together with the diphenols but can also be added at a later stage of the synthesis.
Phenols such as phenol, alkylphenols such as cresol and 4-tert. butyl phenol, chlorophenol, bromophenol, cumyl phenol or mixtures thereof in amounts of 1-20 mol % preferably 2-10 mol % per mol bisphenol, are preferred as chain stoppers for the polyformals used as materials in the coextruded coating. Phenol, 4-tert. butyl phenol or cumyl phenol are preferred.
The polyformals and copolyformals of the formulae (1a) and (1b) or (2 a-d) may be produced, for example, by a solvent process, characterised in that the bisphenols and chain stoppers are reacted with methylene chloride or alpha, alpha-dichlorotoluene in a homogeneous mixture of methylene chloride or alpha, alpha-dichlorotoluene and a suitable high-boiling solvent, such as for example, N-methyl pyrrolidone (NMP), dimethyl formamide (DMF), dimethyl sulfoxide (DMSO), N-methyl caprolactam (NMC), chlorobenzene, dichlorobenzene, trichlorobenzene or tetrahydrofuran (THF) in the presence of a base, preferably sodium hydroxide or potassium hydroxide, at temperatures of 30 to 160° C. Preferred high-boiling solvents are NMP, DMF, DMSO and NMC, NMP, NMC, DMSO being particularly preferred and NMP and NMC being most particularly preferred. The reaction may be carried out in several stages. The optionally required separation of the cyclic impurities takes place after neutral washing of the organic phase by a precipitation process in or by fractionated kneading of the raw product with a solvent that dissolves the cyclic compounds, e.g. acetone. The cyclic impurities are dissolved almost completely in the solvent and may be almost completely separated off by kneading in portions and changing the solvent. By using e.g. ca 10 liters of acetone, which is added for example in 5 portions to a polyformal quantity of ca 6 kg, a cycle content of well below 1% may be achieved after kneading.
The cyclic polyformals and copolyformals may also be separated off by a precipitation process in suitable solvents, which act as non-solvents for the desired polymer and as solvents for the undesirable cycles. These are preferably alcohols or ketones.
The reaction temperature is 30° C. to 160° C., preferably 40° C. to 100° C., particularly preferably 50° C. to 80° C. and most particularly preferably 60° C. to 80° C.
The present invention thus provides the use of the polyformals and copolyformals disclosed for the production of multi-layer products, for example coextrudates such as multi-layer sheets, these multi-layer sheets themselves and a process for their production by coextrusion, as well as compositions containing these polyformals or copolyformals and UV absorbers.
The present invention also provides a product containing the cited multilayer sheet or other coated products based on polyformals. This product, which for example contains the cited multilayer sheet or is itself coated, is preferably selected from the group consisting of baby bottles, water bottles or medical articles that can be sterilised in superheated steam.
The present invention further provides a product that-contains the stated multi-layer sheet or other coated product based on polyformal. This product which, for example, contains the stated multi-layer sheet, is preferably selected from the group consisting of glazing, greenhouse, conservatory, veranda, car port, bus shelter, roofing, partition wall, pay kiosk, road sign, advertising board, display, lighting element, photovoltaic module and solar collector.
The multi-layer product according to the invention has numerous advantages. In particular, it has the advantage that the UV protective layer based on polyformal achieves a significant improvement in long-term resistance, in particular resistance to UV and hydrolysis. In addition, the sheet can be produced easily and inexpensively, all starting materials are available and inexpensive. The remaining positive properties of the polycarbonate, for example its good optical and mechanical properties, are not impaired, or are only negligibly impaired, in the multi-layer product according to the invention.
The multi-layer products according to the invention have further advantages over current products. The multi-layer products according to the invention may be produced by coextrusion. This offers advantages over a product produced by lacquering. Thus no solvents evaporate during coextrusion, as they do during lacquering.
In addition, the storage stability of lacquers is limited. Coextrusion does not have this disadvantage.
In addition, lacquers require costly technology. For example, they require explosion-protected units when using organic solvents, the recycling of solvents, and thus high investment in plant. Coextrusion does not have this disadvantage.
A preferred embodiment of the present invention is the so-called multi-layer sheet, wherein the base sheet includes polycarbonate and/or copolycarbonate and/or polyester and/or copolyester and/or polyester carbonates and/or polymethyl methacrylate and/or polyacrylates and/or blends of polycarbonate and polyesters and/or polymethyl methacrylates and the coextruded layer (coex layer) includes polyformals or copolyformals or blends of these with (co)polycarbonate and/or (co)polyesters.
According to the invention, multi-layer products in which the coex layer contains additionally 0 to 20% UV absorber and is 10 to 500 μm thick are preferred.
The multi-wall sheets may be twin-wall sheets, triple-wall sheets, quadruple-wall sheets etc. The multi-wall sheets may also have different profiles such as e.g. X profiles or XX profiles. In addition, the multi-wall sheets may also be corrugated multi-wall sheets.
A preferred embodiment of the present invention is a two-layer sheet, containing a layer-of polycarbonate and a coex layer of polyformal or copolyformal or a polycarbonate-polyformal blend.
A further preferred embodiment of the present invention is a three-layer sheet containing a layer of polycarbonate as the base layer and two coex layers on top of this, each of which contains similarly or variously of polyformal or copolyformal or a polycarbonate-polyformal blend.
In a particular embodiment, the multi-layer products are transparent.
A preferred embodiment of the present invention is the cited multilayer sheet or various types of bottle, the base layer consisting of polycarbonate and/or copolycarbonate and/or polyester and/or copolyester and/or polyester carbonates and/or polymethyl methacrylate and/or polyacrylates and/or blends of polycarbonate and polyesters and/or polymethyl methacrylates and the coex layer consisting of polyformals or copolyformals or blends thereof with (co)polycarbonate and/or (co)polyesters.
Multilayer products in which the hydrolysis protection layer is 1 to 5000 μm thick, preferably 5 to 2500 μm, most particularly preferably 10 to 500 μm, are preferred according to the invention.
Containers within the meaning of the present invention can be used for the packaging, storage or transport of liquids, solids or gases. Containers for the packaging, storage or transport of liquids are preferred (liquid containers), containers for the packaging, storage or transport of water (water bottles) being particularly preferred.
Containers within the meaning of the invention are blown containers having a volume of preferably 0.1 l to 50 l, preferably 0.5 l to 50 l, volumes of 1 l, 5 l, 12 l and 20 l being most particularly preferred.
Water bottles having a volume of 3 to 5 gallons are most particularly preferred.
The containers have an empty weight of preferably 0.1 g to 3000 g, by preference 50 g to 2000 g and particularly preferably 650 g to 900 g.
The wall thicknesses of the containers are preferably 0.5 mm to 5 mm, by preference 0.8 mm to 4 mm.
Containers within the meaning of the present invention have a length of preferably 5 mm to 2000 mm, particularly preferably 100 mm to 1000 mm.
The containers have a maximum perimeter of preferably 10 mm to 250 mm, by preference 50 mm to 150 mm and most particularly preferably 70 to 90 mm.
Containers within the meaning of the invention preferably have a bottle neck of a length of preferably 1 mm to 500 mm, by preference 10 mm to 250 mm, particularly preferably 50 mm to 100 mm and most particularly preferably 70 to 80 mm.
The wall thickness of the bottle neck of the containers varies between preferably 0.5 mm and 10 mm, particularly preferably between 1 mm and 10 mm and most particularly preferably between 5 mm and 7 mm.
The diameter of the bottle neck varies between preferably 5 mm and 200 mm. 10 mm to 100 mm are particularly preferred, and 45 mm to 75 mm are most particularly preferred.
The bottle base of the containers according to the invention has a diameter of preferably 10 mm to 250 mm, preferably 50 mm to 150 mm and most particularly preferably 70 to 90 mm.
Containers within the meaning of the present invention can have any geometrical shape, they can be e.g. round, oval or polygonal or angular with e.g. 3 to 12 sides. Round, oval and hexagonal shapes are preferred.
The design of the containers can be based on any surface texture. The surface textures are preferably smooth or ribbed. The containers according to the invention can also display several different surface textures. Ribs or beads can run around the perimeter of the containers. They can be any distance apart or can be several different distances apart. The surface textures of the containers according to the invention can display roughened or integrated textures, symbols, ornaments, coats of arms, company logos, trademarks, monograms, manufacturer's instructions, material descriptions and/or volume information.
The containers according to the invention can display any number of handles, which can be located on the side, top or bottom. The handles can be external or can be integrated into the contour of the container. The handles can be folding or fixed. The handles can be of any shape, e.g. oval, round or polygonal. The length of the handles is preferably from 0.1 mm to 180 mm, preferably from 20 mm to 120 mm.
In addition to the polycarbonate according to the invention the containers according to the invention can also contain other substances to a small extent, e.g. seals made from rubber or handles made from other materials.
The containers according to the invention are preferably produced by extrusion blow moulding or injection blow moulding.
In a preferred embodiment of the process for producing the containers according to the invention, the polycarbonates according to the invention are processed on extruders having a smooth or grooved, preferably a smooth, feed section.
The drive power of the extruder is chosen according to the screw diameter. By way of example, with a screw diameter of 60 mm the drive power of the extruder is approx. 30 to 40 kW, with a screw diameter of 90 mm it is approx. 60 to 70 kW.
The universal three-section screws conventionally used in the processing of engineering thermoplastics are suitable.
For the production of containers having a volume of 1 l a screw diameter of 50 to 60 mm is preferred. For the production of containers having a volume of 20 l a screw diameter of 70 to 100 mm is preferred. The length of the screws is preferably 20 to 25 times the diameter of the screw.
In the case of blow moulding, the blow mould is preferably heated to 50 to 90° C. to obtain a sparkling and high-quality container surface.
To ensure uniform and effective heating of the blow mould, the base area and the jacket area can be heated separately.
The blow mould is preferably closed with a compressive force of 1000 to 1500 N per cm of pinch-off weld length.
Before processing, the polycarbonate according to the invention is preferably dried so that the optical quality of the containers is not diminished by streaks or bubbles and the polycarbonate is not degraded hydrolytically during processing. The residual moisture content after drying is preferably less than 0.01 wt. %. A drying temperature of 120° C. is preferred. Lower temperatures do not guarantee adequate drying, whilst at higher temperatures there is a risk of the granules of polycarbonate sticking together and then no longer being able to be processed. Dry-air dryers are preferred.
The preferred melt temperature during processing of the polycarbonate according to the invention is 230° to 300° C.
The containers according to the invention can be used for the packaging, storage or transport of liquids, solids or gases. The embodiment as containers which are used for example for the packaging, storage or transport of liquids is preferred. The embodiment as a water bottle which can be used for example for the packaging, storage or transport of water is particularly preferred.
A preferred embodiment of the invention is the one wherein the containers made from branched polycarbonate are characterised in that the branched polycarbonate contains THPE and/or IBC as branching agent and wherein alkyl phenols are used in the production of the branched polycarbonate and wherein the container is a water bottle.
A particularly preferred embodiment of the invention is the one wherein the container made from branched polycarbonate is characterised in that the branched polycarbonate contains THPE and/or IBC as branching agent and wherein phenol is used in the production of the branched polycarbonate and wherein the polycarbonate has a melt viscosity of 5500 to 7000 Pas at 260° C. and a shear rate of 10 s−1 and a melt viscosity of 900 to 1100 Pas at 260° C. and a shear rate of 1000 s−1 and has an MFR (melt flow index, measured according to ISO 1133) of <3.5 g/10 min and wherein the container is a water bottle.
A particularly preferred embodiment of the invention is further the one wherein the container made from branched polycarbonate is characterised in that the branched polycarbonate contains 1,1,1-tris-(4-hydroxyphenyl) ethane (THPE) and/or 3,3-bis-(3-methyl-4-hydroxyphenyl)-2-oxo-2,3-dihydroindole (IBC, isatin bis-cresol) as branching agent and wherein para-tert-butyl phenol and/or para-cumyl phenol and/or para-isooctyl phenol are used in the production of the branched polycarbonate and wherein the container is a water bottle.
Under the last cited embodiment the one that is particularly preferred is the one wherein the branched polycarbonate contains exclusively 1,1,1-tris-(4-hydroxyphenyl) ethane (THPE) and/or 3,3-bis-(3-methyl-4-hydroxyphenyl)-2-oxo-2,3-dihydroindole (IBC, isatin bis-cresol) as branching agent and wherein para-tert-butyl phenol and/or para-cumyl phenol and/or para-isooctyl phenol are used in the production of the branched polycarbonate.
Under the last cited embodiment the one that is particularly preferred is the one wherein the branched polycarbonate contains exclusively 1,1,1-tris-(4-hydroxyphenyl) ethane (THPE) and/or 3,3-bis-(3-methyl-4-hydroxyphenyl)-2-oxo-2,3-dihydroindole (IBC, isatin bis-cresol) as branching agent and wherein para-isooctyl phenol is used in the production of the branched polycarbonate.
In a particular embodiment the multilayer products are transparent.
Both the base material and the coex-layer(s) in the multi-layer sheets according to the invention may contain additives.
The coex layer may contain in particular UV absorbers and mold release agents.
The UV absorbers or mixtures thereof are generally present in concentrations of 0-20 wt. %. 0.1 to 20 wt. % being preferred, 2 to 10 wt. % being preferred in particular and 3 to 8 wt. % being preferred most particularly. These quantities apply generally, but must be specified individually by the person skilled in the art by a few routine tests depending on the UV absorber. If two or more coex layers are present, the proportion of UV absorber in these layers may also be different.
The present application provides the corresponding compositions of polyformals or copolyformals and UV absorbers.
The concentrations of the UV absorber given generally above and given below for individual UV absorbers apply also for these compositions.
Examples of UV absorbers, which maybe used according to the invention, and their preferred concentrations in the coating are given below.    a) Benzotriazol derivatives of formula (I):
In formula (I) R and X are the same or different and mean H or alkyl or alkylaryl.    Tinuvin 329 in which X=1,1,3,3-tetramethylbutyl and R═H    Tinuvin 350 in which X=tert. butyl and R=2-butyl    Tinuvin 234 in which X═R=1,1-dimethyl-1-phenyl are preferred.
Tinuvin 234Preferred range: 0.00001-1.5 wt. % to 2-20 wt. %, particularly preferably 0.01-1.0 wt. % to 3-10 wt. % most particularly preferably 0.1-0.5 wt. % to 4-8 wt. %.    b) Dimeric benzotriazole derivatives of formula (II):
In formula (II) R1 and R2 are the same or different and mean H, halogen, C1-C10-alkyl, C5-C10-cycloalkyl, C7-C13-aralkyl, C6-C14-aryl, —OR5 or —(CO)— O—R5 in which R5═H or C1-C4-alkyl.
In formula (II) R3 and R4 are also the same or different and mean H, C1-C4-alkyl, C5-C6-cycloalkyl, benzyl or C6-C14-aryl.
In formula (II) m means 1, 2 or 3 and n 1, 2, 3 or 4.    Tinuvin 360 in which R1═R3═R4═H; n=4; R2=1,1,3,3-tetramethylbutyl;    m=1 is preferred.Preferred ranges: 0.00001-1.5 wt. % to 2-20 wt. %, particularly preferred 0.01-1.0 wt. % to 3-10 wt. %, most particularly preferred 0.1-0.5 wt. % to 4-8 wt. %.    b1) Dimeric benzotriazole derivatives according to formula (III):
wherein the bridge means
    R1, R2, m and n have the meaning given for formula (II) and in which    p is a whole number from 0 to 3,    q is a whole number from 1 to 10,    Y is equal to —CH2—CH2—, —(CH2)3—, —(CH2)4—, —(CH2)5—, —(CH2)6—, or CH(CH3)—CH2— and    R3 and R4 have the meaning given for formula (II).Tinuvin 840 in which R1═H; n=4; R2=tert. butyl; m=1; R2 is placed in ortho position to the OH group; R3═R4═H; p=2; Y═—(CH2)5—; q=1, is preferred.Preferred ranges: 0.00001-1.5 wt. % to 2-20 wt. %, particularly preferred 0.01-1.0 wt. % to 3-10 wt. %, most particularly preferred 0.1-0.5 wt. % to 4-8 wt. %.    c) Triazine derivatives according to formula (IV):
in which    R1, R2, R3, R4 in formula (IV) are the same or different and are H or alkyl or CN or halogen and X is equal to alkyl.    Tinuvin 1577 in which R1═R2═R3═R4═H; X=hexyl is preferred.    Cyasorb UV-1164 in which R1═R2═R3═R4=methyl; X=octyl.Preferred ranges: 0.00001-1.0 wt. % to 1.5-10 wt. %, particularly preferred 0.01-0.8 wt. % to 2-8 wt. %, most particularly preferred 0.1-0.5 wt. % to 3-7 wt. %.    d) Triazine derivatives of the following formula (IV a)
in which    R1 means equal to C1-alkyl to C17-alkyl    R2 means equal to H or C1-alkyl to C4-alkyl and    n is equal to 0 to 20.Preferred ranges: 0.00001-1.0 wt. % to 1.5-10 wt. %, particularly preferred 0.01-0.8 wt. % to 2-8 wt. %, most particularly preferred 0.1-0.5 wt. % to 3-7 wt. %.    e) Dimeric triazine derivatives of formula (V):
in which    R1, R2, R3, R4, R5, R6, R7, R8 in formula (V) maybe the same or different and mean H or alkyl or CN or halogenand    X is equal to alkyl or —(CH2CH2—O—)n-C(═O)—.Preferred ranges: 0.00001-1.0 wt. % to 1.5-10 wt. %, particularly preferred 0.01-0.8 wt. % to 2-8 wt. %, most particularly preferred 0.1-0.5 wt. % to 3-7 wt. %.    f) diaryl cyanoacrylates of formula (VI):
in which    R1 to R40 maybe the same or different and mean H, alkyl, CN or halogen.    Uvinul 3030 in which R1 to R40=H is preferred here.Preferred ranges: 0.00001-1.5 wt. % to 2-20 wt. %, particularly preferred 0.01-1.0 wt. % to 3-10 wt. %, most particularly preferred 0.1-0.5 wt. % to 4-8 wt. %.    The UV absorbers selected from the group consisting of Tinuvin 360,    Tinuvin 1577 and Uvinul 3030 are most particularly preferred.

The stated UV absorbers are available commercially.
In addition to the UV stabilisers, the layers may contain other conventional processing auxiliary substances, in particular mold release agents and flow promoters as-well as the stabilisers conventionally used in polycarbonates in particular thermal stabilisers and also dyes, optical brighteners and inorganic pigments.
Layers of all known polycarbonates are suitable as further layers in addition to the polyformal and copolyformal layers, in particular as the base layer of the multi-layer products according to the invention.
Suitable polycarbonates are for example homopolycarbonates, copolycarbonates and thermoplastic polyestercarbonates.
They preferably have average molecular weights Mw of 18,000 to 40,000, preferably of 26,000 to 36,000 and in particular of 28,000 to 35,000, determined by measuring the relative solution viscosity in dichloromethane or in mixtures of equal quantities by weight of phenol/o-dichlorobenzene calibrated by light scattering.
For the production of polycarbonates, refer for example to "Schnell, Chemistry and Physics of Polycarbonate, Polymer Reviews, Vol. 9, Interscience Publishers, New York, London, Syndey, 1964" and to "D.C. PREVORSEK, B. T. DEBONA and Y. KESTEN, Corporate Research Center, Allied Chemical Corporation, Moristown, N.J. 07960, 'Synthesis of Poly(ester)carbonate Copolymers' in Journal of Polymer Science, Polymer Chemistry Edition, Vol. 19, 75-90 (1980)", and to "D. Freitag, U. Grigo, P. R. Müller, N. Nouvertne, BAYER AG, 'Polycarbonates' in Encyclopedia of Polymer Science and Engineering, Vol. 11, Second Edition, 1988, pages 648-718" and finally to "Dres. U. Grigo, K. Kirchner and P. R. Müller 'Polycarbonate', in Becker/Braun, Kunststoff-Handbuch, Vol. 3/1, Polycarbonate, Polyacetale, Polyester, Celluloseester, Carl Hanser Verlag Munich, Vienna 1992, Pages 117-299".
Polycarbonates are preferably produced by the interfacial polycondensation process or the melt-transesterification process, production being illustrated below by the example of the interfacial polycondensation process.
The compounds preferably to be used as starting compounds are bisphenols of the general formulaHO-Z-OH,in which    Z is a divalent organic group having 6 to 30 carbon atoms, which contains one or more aromatic groups.
Examples of such compounds are bisphenols that belong to the group of dihydroxy diphenyls, bis(hydroxyphenyl)alkanes, indane bisphenols, bis(hydroxyphenyl)ethers, bis(hydroxyphenyl)sulfones, bis(hydroxyphenyl)ketones and α,α′-bis(hydroxyphenyl)-diisopropyl benzenes.
Particularly preferred bisphenols, which belong to the above-mentioned groups of compounds are bisphenol A, tetraalkyl bisphenol A, 1,3-bis-[2-(4-hydroxy-phenyl)-2-propyl]benzene (bisphenol M), 1,1-bis-[2-(4-hydroxyphenyl)-2-propyl]benzene, 1,1-bis-(4-hydroxyphenyl)-3,3,5-trimethyl cyclohexane (BP-TMC) and also optionally mixtures thereof.
The bisphenol compounds to be used according to the invention are preferably reacted with carbonic acid compounds, in particular phosgene, or in the melt transesterification process with diphenyl carbonate or dimethyl carbonate.
Polyester carbonates are preferably obtained by reacting the previously mentioned bisphenols, at least one aromatic dicarboxylic acid and optionally carbonic acid equivalents. Suitable aromatic dicarboxylic acids are for example phthalic acid, terephthalic acid, isophthalic acid, 3,3′-or 4,4′-diphenyl dicarboxylic acid and benzophenone dicarboxylic acids. Some, up to 80 mol %, preferably from 20 to 50 mol % of the carbonate groups in the polycarbonates maybe substituted by aromatic dicarboxylic acid ester groups.
Inert organic solvents used in the interfacial polycondensation process are for example dichloromethane, the various dichloroethanes and chloropropane compounds, tetrachloromethane, trichloromethane, chlorobenzene and chlorotoluene; chlorobenzene or dichloromethane or mixtures of dichloromethane and chlorobenzene are preferred.
The interfacial polycondensation reaction maybe accelerated by catalysts such as tertiary amines, in particular N-alkyl piperadine or onium salts. Tributyl amine, triethyl amine and N-ethyl piperadine are preferably used. In the melt transesterification process, the catalysts named in DE-A 4238123 are preferably used.
The polycarbonates may be branched in a conscious and controlled manner by using small quantities of branching agents. Some suitable branching agents are: phloroglucinol, 4,6-dimethyl-2,4,6-tri-(4-hydroxyphenyl)-heptene-2; 4,6-dimethyl-2,4,6-tri-(4-hydroxyphenyl)-heptane; 1,3,5-tri-(4-hydroxyphenyl)-benzene; 1,1,1-tri-(4-hydroxyphenyl)-ethane; tri-(4-hydroxyphenyl)-phenyl methane; 2,2-bis-[4,4-bis-(4-hydroxyphenyl)-cyclohexyl]-propane; 2,4-bis-(4-hydroxyphenyl-isopropyl)-phenol; 2,6-bis-(2-hydroxy-5′-methyl-benzyl)-4-methyl phenol; 2-(4-hydroxyphenyl)-2-(2,4-dihydroxyphenyl)-propane; hexa-(4-(4-hydroxyphenyl-isopropyl)-phenyl)-orthoterephthalic acid ester; tetra-(4-hydroxyphenyl)-methane; tetra-(4-(4-hydroxyphenyl-isopropyl)-phenoxy)-methane; α,α′,α″-tris-(4-hydroxyphenyl)-1,3,5-triisopropyl benzene; 2,4-dihydroxybenzoic acid; trimesic acid; cyanuric chloride; 3,3-bis-(3-methyl-4-hydroxyphenyl)-2-oxo-2,3-dihydroindol; 1,4-bis-(4′,4″-dihydroxytriphenyl)-methyl)-benzene and in particular 1,1,1-tri-(4-hydroxyphenyl)-ethane and bis-(3-methyl-4-hydroxyphenyl)-2-oxo-2,3-dihydroindol.
The 0.05 to 2 mol %, in relation to the diphenols used, of branching agents, or mixtures of branching agents, optionally also to be used maybe used together with the diphenols, but may also be added at a later stage of synthesis.
Phenols such as phenol, alkylphenols such as cresol and 4-tert. butyl phenol, chlorophenol, bromophenol, cumyl phenol or mixtures thereof maybe used in quantities of 1-20 mol %, preferably 2-10 mol % per mol bisphenol as chain stoppers. Phenol, 4-tert. butyl phenol or cumyl phenol are preferred.
Chain stoppers and branching agents maybe added to the synthesis separately but also together with the bisphenol.
The production of polycarbonates by the melt transesterification process is disclosed for example in DE-A 42 38 123.
Preferred polycarbonates are the homopolycarbonate based on bisphenol A, the homopolycarbonate based on 1,1-bis-(4-hydroxyphenyl)-3,3,5-trimethyl cyclo-hexane and the copolycarbonates based on the two monomers bisphenol A and 1,1-bis-(4-hydroxyphenyl)-3,3,5-trimethyl cyclohexane and the copolycarbonates based on the two monomers bisphenol A and 4,4′-dihydroxy diphenyl (DOD).
The homopolycarbonate based on bisphenol A is particularly preferred.
All thermoplastics used in the products according to the invention may contain stabilisers. Suitable stabilisers are for example phosphines, phosphites or Si-containing stabilisers and other compounds disclosed in EP-A 0 500 496. Examples are triphenyl phosphites, diphenylalkyl phosphites, phenyl dialkyl phosphites, tris-(nonylphenyl)phosphite, tetrakis-(2,4-di-tert.-butylphenyl)-4,4′-biphenylene-diphosphonite and triaryl phosphite. Triphenyl phosphine and tris-(2,4-di-tert. butyl phenyl) phosphite are particularly preferred.
These stabilisers may be present in all layers of the multi-layer sheet according to the invention. That means both in the so-called base and in the so-called coex layer or layers. Different additives and concentrations of additives maybe present in each layer.
Furthermore, the multi-layer sheet according to the invention may contain 0.01 to 0.5 wt. % of esters or partial esters of mono- to hexavalent alcohols, in particular of glycerine, of pentaerythritol or of guerbet alcohols.
Monovalent alcohols are for example stearyl alcohol, palmityl alcohol and guerbet alcohol.
A divalent alcohol is for example glycol.
A trivalent alcohol is for example glycerine.
Tetravalent alcohols are for example pentaerythritol and mesoerythritol.
Pentavalent alcohols are for example arabitol, ribitol and xylitol.
Hexavalent alcohols are for example mannitol, glucitol (sorbitol) and dulcitol.
The esters are preferably the monoesters, diesters, triesters, tetraesters, pentaesters and hexaesters or mixtures thereof, in particular statistical mixtures of-saturated aliphatic C10 to C36-monocarboxylic acids and optionally hydroxy-monocar-boxylic acids, preferably with saturated, aliphatic C14 to C32-monocarboxylic acids and optionally hydroxy-monocarboxylic acids.
The commercially obtainable fatty acid esters, in particular of pentaerythritol and glycerine, may contain <60% differing partial esters, depending on the production method.
Saturated, aliphatic monocarboxylic acids having 10 to 36 carbon atoms are, for example, caprinic acid, lauric acid, myristinic acid, palmitic acid, stearic acid, hydroxystearic acid, arachic acid, behenic acid, lignoceric acid, cerotinic acid and montanic acid.
Preferred saturated aliphatic monocarboxylic acids having 14 to 22 carbon atoms are for example myristinic acid, palmitic acid, stearic acid, hydroxystearic acid, arachic acid and behenic acid.
Saturated aliphatic monocarboxylic acids such as palmitic acid, stearic acid and hydroxystearic acid are particularly preferred. The saturated aliphatic C10 to C36-carboxylic acids and the fatty acid esters are per se either known from the literature or maybe produced by processes known from the literature. Examples of pentaerythritol fatty acid esters are those of the particularly preferred monocarboxylic acids named above.
Esters of pentaerythritol and glycerine with stearic acid and palmitic acid are particularly preferred.
Esters of guerbet alcohols and of glycerine with stearic acid and palmitic acid and optionally hydroxystearic acid are particularly preferred.
These esters maybe present both in the base and in the coex layer or layers. Different additives or concentrations maybe present in each layer.
The multi-layer sheets according to the invention may contain antistatics.
Examples of antistatics are cation-active compounds, for example quaternary ammonium-, phosphonium- or sulfonium salts, anion-active compounds, for example alkyl sulfonates, alkyl sulfates, alkyl phosphates, carboxylates in the form of alkali- or earth alkali metal salts, non-ionogenic compounds, for example polyethylene glycol esters, polyethylene glycol ethers, fatty acid esters, ethoxylated fatty amines. Preferred antistatics are non-ionogenic compounds.
These antistatics may be present both in the base and in the coex layer or layers. Different additives and or concentrations may be present in each layer. They are preferably used in the coex layer or layers.
The multi-layer sheets according to the invention may contain organic dyes, inorganic colour pigments, fluorescent dyes and, particularly preferably, optical brighteners.
These dyes may be present both in the base and in the coex layer or layers. Different additives and concentrations may be present in each layer.
All molding compositions used for the production of the multi-layer sheet according to the invention, their feedstocks and solvents may be contaminated with impurities from production and storage, the aim being to work with starting materials that are as clean as possible.
The individual components of the molding compositions maybe mixed in the known way successively or simultaneously and either at room temperature or at a higher temperature.
The additives, in particular the UV absorbers and other previously-mentioned additives, are incorporated into the molding compositions for the sheets according to the invention preferably in the known way by mixing polymer granulate with the additives at temperatures of approximately 200 to 330° C. in conventional units such as internal kneaders, single-screw extruders and twin-shaft extruders, for example by melt compounding or melt extrusion or by mixing the solutions of the polymer with solutions of the additives and then evaporating the solvents in the known way. The proportion of the additives in the molding compositions maybe varied within broad limits and depends on the desired properties of the molding composition. The total proportion of additives in the molding composition is preferably approximately up to 20 wt. %, preferably 0.2 to 12 wt. % in relation to the weight of the molding composition.
The UV absorbers maybe incorporated into the molding compositions for example by mixing solutions of the UV absorbers and optionally other previously-named additives with solutions of the plastics in suitable organic solvents such as CH2Cl2, halogen alkanes, halogen aromatics, chlorobenzene and xylenes. The substance mixtures are then preferably homogenised in the known way by extrusion; the solution mixtures are preferably removed in the known way by evaporating out the solvent followed by extrusion, for example compounded.
It is possible to process the multi-layer sheets according to the invention e.g. by deep drawing or by surface processing such as e.g. providing with scratch-resistant lacquers, water-repelling layers and similar and the products produced by these processes are also provided by the present invention.
Coextrusion per se is known from the literature (see for example EP-A 0 110 221 and EP-A 0 110 238). In the present case the process is preferably carried out as follows. Extruders for the production of the core layer and top layer(s) are connected to a coextrusion adapter. The adapter is constructed in such a way that the melt forming the top layer(s) is bonded in a thin layer to the melt of the core layer. The multi-layer melt strand thus produced is then shaped as required (multi-wall or solid sheet) in the nozzle connected behind it. The melt is then cooled under controlled conditions in the known way by calendaring (solid sheet) or vacuum calibration (multi-wall sheet) and then cut to length. After calibration, a tempering oven may optionally be used to eliminate tension. Instead of fitting an adapter in front of the nozzle, the nozzle itself may also be designed in such a way that the melts are joined together there.
The invention is further explained by the following examples without being restricted to them. The examples according to the invention represent only preferred embodiments of the present invention.

Polyformals as a coextrusion protective layer on polycarbonate

Abstract: in which O-D-O and O-E-O independently denote a diphenolate group, -D- and -E- independently denote an aromatic group having 6 to 40 carbon atoms, k is a whole number from 1 to 1500, o stands for numbers from 1 to 1500, and m is z/o and n is (o-z)/o wherein z is 0 to o.


Deployment and control actuation mechanisms are incorporated in unmanned aerial vehicles having folding wings and/or folding canards and/or a folding vertical stabilizer. The folding canards and folding vertical stabilizer can be deployed using respective four-bar over-center mechanisms. Elevators pivotably mounted to the folding canards and a rudder pivotably mounted to the folding vertical stabilizer can be controlled by means of respective twist link mechanisms. The folding wings have respective wing roots that are driven by respective gas springs to pivot on bearings about a wing root hub having control servo wire paths.

This disclosure generally relates to mechanisms for deploying and actuating airfoil-shaped bodies on compressed carriage unmanned aerial vehicles. In particular, this disclosure relates to mechanisms for deploying wings, canards or vertical stabilizers and mechanisms for actuating trailing edge control surfaces on compressed carriage unmanned aerial vehicles.
Unmanned surveillance air vehicles, glide munitions, winged missiles, and other types of unmanned aerial vehicles (UAVs) are sometimes configured to be carried internally or externally on a larger mother aircraft (or a submarine). Because the carried UAV itself is usually small and typically has a limited range, it is flown to a location near to where it is to perform its mission, as cargo on the mother aircraft, and then air launched to perform the mission. The carried UAV may later be recovered, or it may be considered expendable and destroyed at the completion of the mission.
A known carried UAV has laterally extending wings and canards and a vertical stabilizer which, in the absence of foldability, would make it awkward to store the carried UAV on the mother aircraft or submarine. To facilitate the internal or external storage and transport on the mother aircraft or submarine, the carried UAV may be provided with folding wings, canards and vertical stabilizer. The folding wings, canards and vertical stabilizer are in storage positions during carriage, and then are unfolded to a deployed flight position shortly after launch from the mother aircraft or submarine. The UAV is launched from a mother aircraft at high speed in a compressed carriage state. First a balloon is inflated to slow down the UAV and then a parachute is deployed to stabilize the UAV. The folded wings, canards and vertical stabilizer are then deployed and the engine of the UAV is started. The UAV is then able to fly under remote control by the mother aircraft. The UAV could also be controlled by a remote ground control station, ship, submarine, etc.
There is a need for improved mechanisms for deploying folding wings, canards and vertical stabilizers and actuating control surfaces on UAVs of the foregoing type.

Mechanisms for deploying and actuating airfoil-shaped bodies on unmanned aerial vehicles


A modular Galois-field subfield-power integrated inverter-multiplier circuit that may be used to perform Galois-field division over GF(245). The integrated inverter-multiplier circuit combines subfield-power and parallel multiplication and inversion operations performed therein. The circuit is modular, has a relatively low gate count, and is easily pipelined because it does not use random logic. The circuit implements mathematical calculations known as “Galois-field arithmetic” that are required for a variety of digital signaling and processing applications such as Reed-Solomon and Bose-Chaudhuri-Hochquenghem (BCH) error-correction coding systems. Galois-field division is particularly difficult, typically requiring either a great deal of time or highly complex circuits, or both. The circuit uses a unique combination of subfield and power inversion techniques to carry out multiplicative inversion. Furthermore, the circuit uniquely implements Galois-field division by carrying out the multiplicative inversion and the multiplication simultaneously and in parallel. This substantially increases computation speed. The modularity and pipelineability of the present invention also make system design easier and increases the speed and reduces the gate count of an integrated circuit embodying the inverter-multiplier circuit.

The present invention relates generally to error correction decoders, and more particularly, to a modular Galois-field subfield-power integrated inverter-multiplier circuit that may be used to implement Galois-field division over GF(245).
The closest previously known solutions to the problem addressed by the present invention are disclosed in U.S. Pat. No. 4,975,867 entitled "Apparatus for dividing elements of a Galois Field GF(2QM)" issued to Weng, U.S. Pat. No. 5,612,910 entitled "Circuit for inverting elements of a finite field" issued to Meyer, U.S. Pat. No. 5,467,297 entitled "Finite field inversion" issued to Zook, and U.S. Pat. No. 5,379,243 entitled "Method and apparatus for performing finite field division" issued to Greenberger et al.
U.S. Pat. No. 4,975,867 discloses an apparatus and/or method which enables one to divide two elements, A and B, of GF(22M), that is, perform the operation B/A, by finding the multiplicative inverse of the divisor A, and then multiplying the inverse by the numerator, B. The multiplicative inverse, A−1, of A is found by computing a conversion factor, D, and then multiplying A by D to convert it to an element C, where C is also an element of a smaller Galois Field, GF(2M), which is a subfield of GF(22M). Specifically, C is equal to A2M+1), or A2M*A, in the field GF(22M). Next, the multiplicative inverse, C−1, of C in GF(2M) is found by appropriately entering a stored look-up table containing the 2M elements of GF(2M). The multiplicative inverse, C−1, of C is thereafter converted, by multiplying it by the conversion factor D calculated above, to the element of GF(22M) which is the multiplicative inverse, A−1, of the original divisor, A. The multiplicative inverse, A−1, of A is then multiplied by B to calculate the quotient, B/A.
U.S. Pat. No. 5,612,910 discloses a circuit for inverting a number of n bits of a finite field of 2n=N+1 elements comprises a first circuit for raising to the power t=2n/2 receiving the number to invert. A first complete multiplier receives the number to invert and the output of the circuit for raising to the power t. A second circuit provides the product of the output of the circuit for raising to the power t and the inverse of the output of the first complete multiplier.
U.S. Pat. No. 5,467,297 discloses an inversion circuit (212) determines an inverse B−1 of an m-bit symbol B, the symbol B being expressed in a dual basis representation. Inversion circuit (212) includes an iterative convolution circuit (124A, 124B, 124C) to which the symbol B is applied and which generates and stores electrical signals corresponding to an m-bit value A. The value A is in a first basis representation and is generated by the convolution circuit such that an inner product of A and αkB is equal to 0 for k<m−1. A feedback circuit (128) is provided for enabling the convolution circuit to perform a convolution with an α multiple of B. A multiplier circuit (102) is connected to the convolution circuit and generates electrical output signals corresponding to the product of the value A and α−t. The electrical output signals from the multiplier represent Aα−t=B−1 (i.e., the inverse of the m-bit symbol B in the first basis representation). When necessary, the m-bit value A is bit-positionally justified, either by operating the convolution circuit as a shift register or by loading the value A into a shift register (132).
U.S. Pat. No. 5,379,243 discloses an apparatus and method are provided for simplifying a finite field division, including inputs for the initial condition signals a(x), b(x), and p(x), and providing at an output node the signal c(x), where c(x)=a(x)/b(x) without intermediate inverter circuitry for finding 1/b(x). A reference register initialized to b(x), and a divider register initialized to a(x). Both registers are manipulated in parallel by a logic circuit which responds to the contents of the reference register, converting its contents to 1. By applying the same manipulations to the divider register, its contents are converted from a(x) to a(x)/b(x). One embodiment of a finite field divider according to the present invention is used to provide a single finite field division of a single set of values a(x), b(x) and p(x). Another embodiment processes continuous streams of a(x), b(x) and p(x) values, to provide a continuous stream of c(x) values delayed by a calculation time. In another embodiment, p(x) is not a stream of values, but a constant either applied to the p(x) input of the finite field divider circuit or a constant defined by fixed circuit elements within the divider circuit.
However, known prior art approaches do not combine power inversion and subfield techniques are not combined to carry out the multiplicative inverse computation. Also, known prior art approaches do not simultaneously carry out multiplicative inversion and multiplication operations in parallel using a modular structure to increase the speed with which a full division operation can be carried out. Prior art approaches do not have a modular structure that allows natural pipelining of data and provide for increased clock speed. Furthermore, prior art approaches do not have a modular structure that eases circuit design, testing and implementation. Also, prior art approaches do not provide for a circuit that is completely asynchronous.
Accordingly, it is an objective of the present invention to provide for a modular Galois-field subfield integrated inverter-multiplier circuit for use in performing Galois-field division. It is also an objective of the present invention to provide for a modular Galois-field subfield integrated inverter-multiplier circuit that may be specifically used to perform Galois-field division over GF(245).

Modular Galois-field subfield-power integrated inverter-multiplier circuit for Galois-field division over GF(256)


The invention provides methods of relating a plurality of images based on measures of similarity. The methods of the invention are useful in the segmentation of a sequence of colposcopic images of tissue, for example. The methods may be applied in the determination of tissue characteristics in acetowhitening testing of cervical tissue, for example.

It is common in the medical field to perform visual examination to diagnose disease. For example, visual examination of the cervix can discern areas where there is a suspicion of pathology. However, direct visual observation alone is often inadequate for identification of abnormalities in a tissue.
In some instances, when tissues of the cervix are examined in vivo, chemical agents such as acetic acid are applied to enhance the differences in appearance between normal and pathological areas. Aceto-whitening techniques may aid a colposcopist in the determination of areas where there is a suspicion of pathology.
However, colposcopic techniques generally require analysis by a highly trained physician. Colposcopic images may contain complex and confusing patterns. In colposcopic techniques such as aceto-whitening, analysis of a still image does not capture the patterns of change in the appearance of tissue following application of a chemical agent. These patterns of change may be complex and difficult to analyze. Current automated image analysis methods do not allow the capture of the dynamic information available in various colposcopic techniques.
Traditional image analysis methods include segmentation of individual images. Segmentation is a morphological technique that splits an image into different regions according to one or more pre-defined criteria. For example, an image may be divided into regions of similar intensity. It may therefore be possible to determine which sections of a single image have an intensity within a given range. If a given range of intensity indicates suspicion of pathology, the segmentation may be used as part of a diagnostic technique to determine which regions of an image may indicate diseased tissue.
However, standard segmentation techniques do not take into account dynamic information, such as a change of intensity over time. This kind of dynamic information is important to consider in various diagnostic techniques such as aceto-whitening colposcopy. A critical factor in discriminating between healthy and diseased tissue may be the manner in which the tissue behaves throughout a diagnostic test, not just at a given time. For example, the rate at which a tissue whitens upon application of a chemical agent may be indicative of disease. Traditional segmentation techniques do not take into account time-dependent behavior, such as rate of whitening.

Image processing using measures of similarity


The method of controlling a pressure control solenoid valve which controls hydraulic pressure in a hydraulic control system for an automatic transmission of a vehicle first senses a plurality of vehicle operating conditions, and detects a power-on vehicle operating state based on the sensed vehicle operating conditions. Next, the method controls a duty ratio of the pressure control solenoid valve according to predetermined values corresponding to the power-on state when the power-on state detected. The method then detects a change in the vehicle operating state from the power-on state to a power-off state. Upon detection, the method generates an initial duty ratio for the pressure control solenoid valve based on a predetermined duty ratio corresponding to the power-off state and duty ratios supplied to the pressure control solenoid valve during the power-on state. The pressure control solenoid valve is then controlled according to this initial duty ratio during the power-off state.

1. Field of the Invention
The present invention relates to a hydraulic pressure control method of a four-speed automatic transmission. More particularly, it relates to a hydraulic pressure control method when an upshift operation changes from a power-on upshift to a power-off upshift.
2. Discussion of Related Art
Automatic transmissions for vehicles selectively actuate a plurality of friction elements such as clutches and brakes, forming part of the automatic transmission, using a hydraulic control system to obtain different gear ratios. FIG. 1 is a representative example of such a hydraulic control system. U.S. Pat. No. 5,003,842 and 5,540,635 to Hatta et al. and Jang, respectively, both hereby incorporated by reference, disclose other examples.
Because the operation of such conventional hydraulic control systems is so well known and readily ascertainable from the above cited patents, a description of that operation will not be repeated for the sake of brevity. During operation a pressure control solenoid valve 2 controls the line pressure in the hydraulic control system in accordance with duty ratios generated by a transmission control unit (TCU) 4. The TCU 4 typically includes a central processing unit, a read only memory, and a random access memory, The TCU 4 controls the operation of the hydraulic control system based on vehicle operating conditions. A plurality of sensors, such as a vehicle speed sensor, engine speed sensor, load or throttle valve sensor, etc, connected to the TCU 4 convey the vehicle operating conditions.
During operation, if a driver depresses the accelerator pedal, placing a large load on the engine, the automatic transmission enters a power-on state. If the accelerator pedal is then released, the automatic transmission enters a power-off state. FIG. 2A illustrates the duty ratio applied to the pressure control solenoid valve 2 by the TCU 4 (see FIG. 1) of the hydraulic control system when the automatic transmission enters the power-on state and then switches to the power-off state. FIG. 2B illustrates the speed of the turbine of the automatic transmission's torque converter when the pressure control solenoid valve 2 operates according to the duty ratio of FIG. 2A.
FIG. 3 illustrates the flow chart of the control method implemented by the TCU 4 during power-on control. In step S2, the TCU 4 outputs duty ratios according to predetermined duty ratios stored therein. As shown in FIG. 2A, at the beginning of the power-on state SS, a minimum duty ratio is output for a first predetermined period of time. Once the first predetermined period of time expires, the duty ratio is set at a first predetermined value, greater than the minimum duty ratio, for a second predetermined period of time. After expiration of the second predetermined period of time, the TCU 4 sets the duty ratio to a second predetermined value, greater than the first predetermined value, for a third predetermined period of time. After the third predetermined period expires, the duty ratio is set to a third predetermined value which is greater than the second predetermined value.
Processing then proceeds to step S4 where the TCU 4 performs conventional duty ratio control such as disclosed in U.S. Pat. No. 5,086,668 to Fujiwara et al., hereby incorporated by reference, using the third predetermined value as an initial value.
Next, in step S6, the TCU 4 determines whether control of the automatic transmission should switch to the power-off state. If not, conventional duty ratio control continues. If control of the automatic transmission switches to the power-off state, then in step S8, the TCU 4 outputs an initial power-off duty ratio D.sub.off to the pressure control solenoid valve 2.
Afterwards, in step S10, the TCU 4 preforms conventional duty ratio control using the initial power-off duty ratio D.sub.off as an initial value.
As a result of switching from the power-on state to the power-off state, a "Run-Up" phenomenon occurs wherein as shown in FIG. 2B the revolutions per minute (hereinafter referred to as a RPM) of the turbine significantly increases and then lowers. The increase is caused by the decrease in the load place on the engine as a result of decreasing the line pressure in the hydraulic control system because the initial power-off duty ratio is much higher then the previously output duty ratio. As shown in FIG. 4, duty ratio is inversely proportional to line pressure.

Setting the line pressure as a function of a predetermined ratio and power-on state duty ratios during a power-off


The present disclosure relates to a method for managing the charge level of a battery of a mobile terminal connected to a network of transmission of information. The method comprises measuring the charge level of the battery. If the charge level of the battery is lower than a predefined threshold of charge level, the method controls the operation of the terminal to reduce its power consumption during an operation of transmission of information from or toward the terminal.

Professional radioelectric mobile networks, or PMR networks, are secured radioelectric communication networks, generally used by Public Security bodies, such as firemen, police forces, gendarmerie forces and soldiers, or even by companies or administrations.
PMR terminal users use them within the context of often critical outside missions. Within this context, maintaining the charge of the battery at a level sufficient to be able to give and receive calls is a critical element for the lifetime of the mission.
In the past, PMR networks, to return to this example, only allowed voice and short data messages to be transmitted, so that the risk of the battery becoming completely discharged was limited. Currently, these networks also allow, in addition to voice, video and data of the file type, electronic messages, web pages, etc. to be transmitted. Now, these services are heavy power consumers, so that the risk of the battery becoming fully discharged during a mission is indeed real.
Document WO 2007/050687 describes a method for managing the charge level of a battery of a mobile terminal, wherein providing a service to the terminal is delayed as a result of the identification of a low charge level of the battery.
This method is however not applicable to the case of PMR networks, because it could not be contemplated to postpone providing a service, such as a telephone call or a transmission of a message etc., to a PMR terminal, the user of which carries out a critical, even vital, mission, in some situations.

Method for managing the charge level of a battery in a mobile terminal, corresponding management system and computer program


A modular privacy fence, which includes a stringer having two rails, wherein at least the first rail comprises a plurality of fence picket dividers that protrude in a perpendicular direction from the first rail. The modular privacy fence also includes a fastener attached to the end of the stringer, wherein the fastener is arranged to secure the stringer to a fence post, and a bottom rail with a trough. In some embodiments, the second rail may also include a separate plurality of fence picket dividers that protrude from the second rail in a direction perpendicular to the second rail and parallel to the first plurality of fence picket dividers. In such arrangements, the first plurality of fence picket dividers is offset from the second plurality of fence picket dividers in a direction parallel to the first rail.

1. Field of the Invention
This invention relates in general to hand-constructed barriers, and more particularly to a modular privacy fence with individually replaceable pickets.
2. Description of Related Art
A conventional privacy fence is made of a single row of closely arranged wood pickets that must be specially assembled to match the particular contour and geography of the fenced-in area. Gaps often appear between individual pickets, which can limit the privacy afforded by such a fence. Another disadvantage of such a fence is that the wood pickets deteriorate under continuous exposure to sun, wind, and rain conditions, and often wear unevenly. Such wear can increase the visible gaps between the pickets. When individual fence pickets must be replaced, basic carpentry skills and tools are often required to repair the fence. For example, wood fence pickets are commonly secured in place with staples or nails that must be first removed before installing the new picket. Some fence designs even feature a top rail, which must be removed in order to replace individual pickets.
For increased privacy over single-row picket fences, conventional double-row picket fences are assembled using one or more transverse center rails to which two rows of alternating pickets are nailed or stapled to each side of the center rails. One disadvantage of such a design (beyond the need for basic carpentry skills to assemble one), is that substantial gaps are visible when the fence is viewed at an angle, which reduces the privacy of the fence. Other double-picket or staggered fence designs attempt to improve upon the design by replacing the center rails with a top cap rail, which reduces gaps, but requires special assembly on site.
Metal fences, while more resistant to the abovementioned wear, do not offer the same privacy, security, or aesthetic appeal. Moreover, entirely metal fences are much more costly than wood fences and absorb large amounts of heat during daylight hours, which can make them unsuitable for residential purposes.

Modular privacy fence with individually replaceable pickets


Computer-implemented methods and computer-readable storage media are disclosed to facilitate the application of business rules. A rule is received, the rule defining one or more calculations to be performed on specified data stored in a multidimensional database to yield at least one result. At least one database query is generated seeking the specified data to be retrieved from the multidimensional database. An intermediary table is created to accommodate the specified data retrieved from the multidimensional database. The specified data is stored in the intermediary table and the specified data is manipulated when the data is retrieved or after the specified data is stored in the intermediary table.

Database management systems have evolved greatly over the past several years. Database managers once included only hierarchical systems which were satisfactory for information storage and retrieval. Later, relational database managers were developed to maintain data in a tabular form that provided improved flexibility in querying and analyzing data based on selected attributes presented in the rows and columns of the relational tables. More recently, multidimensional data models have provided still greater flexibility in querying and analyzing data stored for the members in any of the dimensions of the multidimensional data models. Multidimensional data models support contemporary forms of business intelligence applications, such as on-line analytical processing (OLAP). Accordingly, multidimensional databases are commonly termed "OLAP cubes."
Analogous to the way in which relational databases are queried using structured query language (SQL) systems, multidimensional data models may be queried using multidimensional expression (MDX) systems. For example, the Microsoft Office PerformancePoint Server 2007 product produced by Microsoft Corporation of Redmond, Wash., allows multidimensional data model to be accessed using MDX queries or MDX scripts in order to give effect to business rules to be applied to the data.
MDX expressions offer tremendous flexibility and, thus, are very powerful business intelligence tools. Nonetheless, MDX expressions may not provide a desirable level of performance when the target size of the expressions becomes very large. For example, performing aggregation functions that calculate sums, averages, or other calculations over a large, multidimensional data structure using MDX queries or MDX scripts may involve performing many calculations over a vast multidimensional cell space. In such cases, the performance resulting from the use of MDX queries or MDX scripts may prove unsatisfactory.

Advanced techniques for SQL generation of performancepoint business rules


A DC voltage converter having a plurality of outputs and a method for converting a DC voltage into a plurality of output-side DC voltages is disclosed. A control unit is used to drive a first and a second switch to drive an energy store in such a manner that a plurality of different output voltages are provided. The switches include field effect transistors, and at least the substrate terminal of one of these field effect transistors is connected to the control unit in order to be driven using a substrate potential in a manner dependent on an operating mode of the DC voltage converter. This makes it possible to provide different voltages both in an intermittent and in a continuous operating mode of the converter with, at the same time, a high degree of efficiency.

DC voltage converters are normally used to convert an input-side DC voltage into an output-side DC voltage. In the case of multichannel DC voltage converters, a plurality of different DC voltages may be provided.
DC voltage converters of this type may, for example, be in the form of so-called step-up converters which belong to the group of secondary-clocked switching regulators. In this case, provision is usually made of a storage inductor (as an inductance) as the energy store and a switch, which is operated using a controllable duty ratio. A distinction is made between flyback converters and forward converters depending on the design of the secondary-clocked switching regulators.
Depending on whether or not the coil current returns to zero in the discharging phase of the step-up converter, a distinction is made between two operating modes, namely intermittent and continuous operation. In a DC voltage converter having a plurality of output branches for providing different output voltages, it is necessary, during continuous operation, to ensure that the switches can be fully switched. When designed in integrated fashion, the switches are, for example, field effect transistors.
During intermittent operation, in contrast, the coil current returns to zero in the discharging phase of the coil. In order to nevertheless achieve a useful degree of efficiency, it is necessary to prevent charge carriers from flowing back from the output of the converter to the input. Diodes are normally provided in each branch for this purpose.
The diodes are, for example, designed using integrated circuit technology.

This patent is subject to a terminal disclaimer.

DC voltage converter and method for converting a DC voltage


Provided is a substrate for epitaxial growth, which enables the improvement in quality of a Ga-containing oxide layer that is formed on a β-Ga2O3 single-crystal substrate. A substrate (1) for epitaxial growth comprises β-Ga2O3 single crystals, wherein face (010) of the single crystals or a face that is inclined at an angle equal to or smaller than 37.5° with respect to the face (010) is the major face. A crystal laminate structure (2) comprises: the substrate (1) for epitaxial growth; and epitaxial crystals (20) which are formed on the major face (10) of the substrate (1) for epitaxial growth and each of which comprises a Ga-containing oxide.

A semiconductor element is known in which a Ga-containing oxide is deposited on an element substrate formed of a β-Ga2O3-based single crystal (see, e.g., PTL 1).
This type of semiconductor element is formed by laminating a layer of n-type or p-type conductivity on a main surface of a β-Ga2O3 single crystal substrate using a physical vapor-phase growth method such as MBE (Molecular Beam Epitaxy) or a chemical vapor-phase growth method such as CVD (Chemical Vapor Deposition).
In addition, a (100) plane having high cleavability and thus providing a flat surface easily is used as the main surface of the β-Ga2O3 single crystal substrate (see, e.g., PTL 2).

Substrate for epitaxial growth, and crystal laminate structure


A tent (10) with extendable windows (14) having a main structure (12) including a plurality of walls (16, 18, 20) which are oriented at a first angle (60) with respect to a vertical reference. The tent (10) also includes at least one window (14) which is extendable to a second angle (62) with respect to a vertical reference, where the second angle (62) is a more negative angle than the first angle (60) thus producing windows (14) which are horizontally extendable further than the tent walls (16, 18, 20).

Tents have been used for centuries as temporary structures for camping trips. During these trips, there may be competing desires for comfort on one hand, while a camper may still desire to get away from the complications of city life. The use of lightweight materials has made the satisfaction of these competing desires more easily accomplished. Tent fabrics, as well as tent poles and frame structures, can now be made to be very strong, while also very lightweight. This use of materials allows more imaginative and varied structures to be designed, which are still light enough to be easily portable, and thus practical for camping trips.
Another pair of competing needs facing campers and users of tents is that of the need for a reasonably small floor space, while providing enough internal volume for comfort. When camping in the woods, the extent of usable flat ground area may be limited, by trees or uneven terrain, thus a tent which has a large "footprint" or floor area will find fewer useable sites than one that has a smaller footprint. At the same time, a user will generally feel a need for "elbow room" and may feel cramped without a reasonable amount of space.
Thus there is a need for a tent which has a compact footprint, but which has an interior volume which is greater than that of a tent having the traditional inwardly tapering, or even strictly vertical walls.


A power conversion system includes a power transfer estimator that is operable to provide a determination of the cumulative amount of power transferred through the power supply, without additional sensing elements and at extremely low power levels, and to provide such determinations periodically over potentially long periods of time commensurate with the lifetime of a limited power source such as a battery. In a power conversion system operating in a discontinuous conduction mode (DCM), the power transfer estimator determines the charge transferred during each switching cycle, and the total number of switching cycles, to calculate the cumulative amount of power transferred. The power transfer estimator is optionally operable to calculate a value for the inductance to be used in the determination of the cumulative amount of power transferred through the power supply.

The amount of power consumed by electronic devices often limits the utility of the electronic devices, especially for electronic devices having limited power sources (such as batteries, capacitors, solar cells, and the like). Because the rates of power consumption within a single electronic device typically vary over time, it can be difficult to determine efficiently the cumulative amount of power consumed by the electronic device at various points of time during operation of the electronic device. Estimation of the power consumption of electronic devices is often determined by using sensing components that entail higher cost and/or higher power consumption.


A power supply circuit has: a power supply filter including a coil which is inserted in series into an input line; a DC--DC converter which is connected to an output of the power supply filter and which converts an input voltage into an arbitrary output voltage; a detecting section which detects a potential difference between ends of the coil; and a control section which controls the output voltage of the DC--DC converter based on the detected potential difference.

1. Field of the Invention
The invention relates to a power supply circuit, and particularly to a power supply circuit for an audio apparatus having a switching type DC--DC converter.
2. Description of the Related Art
It is conventionally known that an excess current caused by a short circuit of a load or the like results in damage of an internal component of a DC--DC converter which constitutes a power supply circuit. An example of a configuration for eliminating such a drawback is disclosed in Japanese Utility Model Publication (Kokai) No. SH062-161587.
FIG. 6 shows a DC--DC converter having an overcurrent detecting circuit disclosed in the above-identified publication. Referring to the figure, a DC--DC converter 6 functions as a power supply for driving a load 74.
An overcurrent detecting section comprises a detecting resistor 71, a reference voltage 4, an overcurrent detecting circuit 72, and an operation stop signal generating circuit 73. The overcurrent detecting circuit 72 compares a voltage drop produced by a current flowing through the detecting resistor 71 inserted in series into an input line, with the reference voltage 4. When the voltage drop is larger than the reference voltage 4, it is determined that the circuit is in an overcurrent condition, and a determination signal is sent to the operation stop signal generating circuit 73. In response to the detection signal indicative of the overcurrent condition, the operation stop signal generating circuit 73 supplies an operation stop signal for stopping the operation of the DC--DC converter 6 to the DC--DC converter 6.
Japanese Utility Model Publication No. SH062-161587 also discloses protection processing for an excess current by utilizing a PWM control IC which is generally used for controlling an output voltage of a switching type DC--DC converter.
Specifically, the circuit is protected in the following manner. When an excess current is produced, the ON duty period of a PWM signal is set to be 0, so as to stop the switching operation of the DC--DC converter.
Such a DC--DC converter is widely used in the field of a sound apparatus. In a power supply circuit for an amplifier which is mounted on a vehicle and used for driving a loudspeaker, particularly, a high output cannot be obtained by using a voltage of a battery (a power supply voltage), and hence the power supply voltage is boosted by the DC--DC converter so that the boosted voltage is used as a power supply for the amplifier.
If a loudspeaker having an impedance which is smaller than a loudspeaker impedance range assumed for the amplifier is used, the above-mentioned overcurrent protecting circuit tries to prevent an excess current from flowing through a switching device and a transformer.
In the above-described protecting circuit, since the switching operation of the DC--DC converter is stopped, also the operation of the amplifier is stopped. Accordingly, the loudspeaker is not driven, and a dropout of reproduced sound occurs.
The detecting resistor 71 which constitutes the overcurrent detecting section is inserted in series into the input line dedicated to the detection of an excess current. Accordingly, an electric power loss due to the overcurrent detection is produced.


Provided are a flash memory management apparatus and method which divide blocks of a memory into data blocks and i-node blocks and respectively specify storage paths of data, which is stored in the data blocks, in the i-node blocks in order to easily access pieces of the data by searching the i-node blocks. The flash memory management apparatus includes a map search module searching for a map block located at a preset position of a memory among blocks that form the memory and extracting storage paths of one or more i-node blocks; a path search module searching for storage paths of data specified in the i-node blocks based on the extraction result; and a data management module accessing the data through a storage path of the data and performs a transaction on the data.

1. Field of the Invention
Apparatuses and methods consistent with the present invention relate to a flash memory management, and more particularly, to a flash memory management apparatus and method which divide blocks of a memory into data blocks and i-node blocks and respectively specify storage paths of a data, which are stored in the data blocks, in the i-node blocks in order to easily access the pieces of data by searching the i-node blocks.
2. Description of the Related Art
Flash memories are constantly-powered nonvolatile memories which can be erased and reprogrammed in units of blocks. Flash memories are a variation of electrically erasable programmable read-only memories (EEPROMs). While EEPROMs can be erased and rewritten at the byte level, flash memories can be rewritten in units of blocks. Therefore, flash memories are faster than EEPROMs.
A flash memory gets its name since the microchip is organized such that a section of memory cells are erased in a single action or flash. The erasure is caused by Fowler-Nordheim tunneling in which electrons pierce through a thin dielectric material to remove an electric charge from a floating gate associated with each memory cell.
A flash memory is not a passive device, such as a dynamic random access memory (DRAM), which includes a simple memory device, a refresh circuit, and an error correction circuit. Instead, the flash memory is an active device which receives commands from a programmer and executes the received commands. The commands are issued using a command user interface (CUI), and the entire state of a system is managed by a write state machine (WSM). Examples of the commands include read, write, and other control commands.
Nonvolatile memories, such as flash memories, have the advantages of both random access memories (RAMs), which can freely write and erase data, and read only memories (ROMs) which can retain stored data without power supply. Therefore, the nonvolatile memories are widely used as storage media of handheld electronic devices such as digital cameras, personal digital assistants (PDAs), and MP3 players.
Similar to related art RAMs or magnetic tapes, nonvolatile memories allow random access to data stored at a predetermined location. However, unlike the related art storage devices, the nonvolatile memories rewrite or erase data in units of erase blocks (hereinafter, referred to as "blocks").
That is, when data is to be corrected, a block including the data is erased, and then the data is rewritten. It is just like deleting a word by pressing a delete key and then rewriting it instead of correcting letters or alphabets in the word one by one.
FIG. 1 illustrates the structure of a related art nonvolatile memory 100. Referring to FIG. 1, the related art nonvolatile memory 100 includes a plurality of blocks 110, and each of the blocks 110 includes a plurality of pages 200.
FIG. 2 illustrates the structure of one of the pages 200 illustrated in FIG. 1. The pages 200 are basic units of reading and writing operations. Each of the pages 200 may be divided into a data region 210 and a spare region 220. The data region 210 stores data, and the spare region 220 records an offset of a logical page which is recorded in a corresponding physical page.
The data region 210 of each of the pages 200 records 512 bytes of data. A file identification (ID) and a chunk number are assigned to each of the pages 200 and recorded in the spare region 220. In addition, two-bit serial numbers are assigned to the pages 200 as the positions of the pages 200 increase. Therefore, even when the same chunk number is assigned to two pages due to a power failure, a hitch or other errors, the pages can be distinguished from each other.
As described above, the spare region 220 exists in each of the pages 200, and information stored in the spare region 220 is used to retrieve data stored in the memory 100. That is, when a user or an apparatus desires to retrieve data stored in the memory 100, the spare regions 220 of the pages 200 are all scanned in order to extract the position of the data.
As the demands for flash memories increase, the integration density of the flash memories has also increased to tens of gigabytes. In order to initialize a memory having a structure as described above, a page can be accessed only after all spare regions of the memory are scanned, which may take more than tens of seconds.
Therefore, there exists a need for easily accessing a target page without scanning the entire memory.

Flash memory management system and apparatus


A light emitting diode (LED) control device includes: a power supply connected to a first driving node and a second driving node of an LED driver configured to provide driving power to a light source including a plurality of LEDs; a controller configured to operate by a first internal power voltage output from the power supply, and receive a control command from an external controller; and a switching device connected to the second driving node, and configured to operate by a second internal power voltage output from the power supply and control brightness of the light source based on a control signal which is output from the controller in response to the control command.

Embodiments of the present disclosure relate to an LED control device and a lighting device including the same.
Alight emitting diode (LED) may have low power consumption and a long lifespan, and has rapidly replaced general fluorescent lamps and incandescent lamps. Recently, various types of lighting devices employing an LED as a light source have been developed and marketed, and research into lighting devices having various functions in addition to a simple lighting function have also been actively conducted. For example, a function of controlling a color temperature and/or brightness of light or monitoring an operating state of LEDs mounted as light sources may be included in a lighting device.

LED control device and lighting device including the same


Extendable bit teeth are supported by the guide grooves formed on the end face at the point of a bit body in such a manner as to be slidable. The extendable bit teeth slide along the guide grooves in an excavating direction to thereby project from the end face at the point of the bit body. The extendable bit teeth slide in an opposite direction to the excavating direction to project from the outer periphery of the point of the bit body. Since the extendable bit teeth are pressed against the ground during excavation, the extendable bit teeth projects from the outer periphery of the point of the bit body so that the bit gauge can be extended, and most of the excavation hole is excavated by the bit body.

1. Field of the Invention
The present invention relates generally to an extendable bit, and more particularly to an extendable bit used in a method in which an air hammer excavates the ground with a casing pipe, preventing the collapse of geological strata.
2. Description of the Related Art
Japanese Patent Publication No. 56-24758 discloses an extendable bit used in the above-mentioned excavation method.
This extendable bit consists of a bit body and bit teeth provided at the point of the bit body. The bit teeth are formed to have substantially the same diameter as the bit body, and the bit teeth are supported by guide grooves formed on a slope at the point of the bit so that the bit teeth can be slidable. A position regulating member regulates the upper and lower positions of the bit teeth. When the bit teeth are pressed against the bottom of an excavation hole, they slide along the guide grooves diagonally upward so that they can be extended. If the bit body rotates in such a state, the bit teeth rotate about an axis of the bit body, and thereby a larger diameter hole than the bit body can be excavated.
The above-mentioned conventional extendable bit, however, has an disadvantage of being weak because there are formed a number of notches such as guide grooves at the center of the bit body.
The conventional extendable bit has another disadvantage in that the excavation cannot be efficiently performed and a large amount of energy must be used in order to perform the task.