摘要:
A method to increase diversity in MIMO fading channels interleaves coordinates of complex symbol(s) in a transmission frame after encoding and modulating. Specifically, an input signal is encoded and modulated into a codeword, jointly across at least two pipes, said pipes having space, time, frequency, or other nature, wherein the codeword spans a frame and is defined as at least one complex symbol whose complex values are all those to be transmitted during all channel uses covered by the frame. Each of the complex symbols have a first and second coordinate. After modulating, which may be combined with encoding in a signal space encoder, the coordinates are interleaved. In modulation, the complex symbols (typically two dimensional) may arise as elements of a multidimensional (typically greater than two dimensions) signal constellation, in which case those multidimensional constellation coordinates are the ones that are interleaved in the frame. The frame carrying the interleaved coordinates is transmitted by the first and at least second antennas, possible opposed sub-frames of the overall frame being transmitted separately by opposed antennas. A coset selector is used in some embodiments to maximize a minimum Hamming distance, and/or a minimum Euclidean distance, between coordinates within a coset to control diversity and/or coding gain. In some embodiments, the operation of the encoder and modulator is such as to maximize a minimum coordinate-wise Hamming distance, and/or a minimum Euclidean distance, between allowable codewords, and/or to provide additional structure for the allowable codewords. A method, transmitter, system, and mobile station are described.
摘要:
Disclosed is a bimodal Ziegler-Natta catalyzed polyethylene, having a density of from 0.930 g/cc to 0.960 g/cc, and a molecular weight distribution of from 10 to 25, wherein an article formed therefrom has a PENT of at least 1500. Also disclosed is a method of preparing a tubular article including obtaining a bimodal polyethylene having a density of from 0.930 g/cc to 0.960 g/cc and a molecular weight distribution of from 10 to 25, and processing the polyethylene under conditions where a specific energy input (SEI) is less than 300 kW·h/ton, and wherein the article has a PENT of at least 1500. Further disclosed is a method for controlling the degradation of polyethylene including polymerizing ethylene monomer, recovering polyethylene, extruding the polyethylene, and controlling the degradation of polyethylene by measuring the SEI to the extruder and adjusting throughput and/or gear suction pressure keep SEI less than 300 kW·h/ton, and forming an article.
摘要:
A polyethylene may be prepared using a mixture of a silica supported catalyst and a magnesium chloride supported catalyst. By changing the ratio of the two catalysts, the polyethylene produced may have a varying bulk density and shear response. The method allows for the tuning or targeting of properties to fit a specific application, such as a blow molding or vapor barrier film.
摘要:
A system is provided for managing an amount of stored energy in a powered system. The powered system is configured to complete a mission from an initial stage to a final stage. The system includes a controller including a memory configured to store a plurality of handling stages. The controller is configured to determine the stored energy at the initial stage based upon the initial stage and a handling stage positioned between the initial stage and the final stage, and selected from among the plurality of handling stages stored in memory. The stored energy is necessary to propagate the powered system from the initial stage to the handling stage upon the occurrence of an anomaly in the powered system. Additionally, a method and computer readable media are provided for managing an amount of stored energy in a powered system.
摘要:
Process for the preparation of a hydroperoxide functionalized olefinic compound in an oxidation reactor containing a particulate catalyst bed comprising a light induced photosensitized catalyst component supported on a particulate substrate material forming a permeable catalyst bed. The photoenergized catalyst component is a photoreductant material which is effective for the conversion of triplet oxygen to singlet oxygen under illumination with ultraviolet or visible light. An oxygen containing feed stream containing triplet oxygen is supplied to the catalyst bed. The catalyst bed is irradiated at an intensity to convert triplet oxygen to singlet oxygen to produce a singlet oxygen enriched gas stream. The enriched gas stream is supplied to a second reactor which contains a dispersion of an olefinic component having an allylic hydrogen which is contacted with the enriched gas stream under conditions effective to cause an allylic rearrangement and introduce hydroperoxide functionalization into the olefinic component.
摘要:
Polyolefins may be prepared using a cocatalyst conforming to the formula: AIRz(Xz)nLzm wherein Rz is a linear or branched organic moiety having at least 5 carbons and Xz is a linear or branched organic moiety having at least 5 carbons or a heterocyclic moiety having at least 4 atoms and can be anionic or di-anionic. The aluminum complex may also be in the form of an adduct complex where Lz is a Lewis base and m=1-3. The cocatalyst Rz components are selected such that they do not react with water under polymerization conditions to form a species that is highly soluble in the polymerization diluent. Use of the specified cocatalyst reduces fouling during metallocene-catalyzed runs and “post-metallocene hangover” when the same production equipment is transitioned to non-metallocene catalyst runs using catalysts such as chromium.
摘要:
A method of forming a polyolefin catalyst component includes halogenating metal complexes. The metal complexes result from reacting a metal alkoxide with an alcohol-ether. A particular non-limiting example is a magnesium complex formed by reacting magnesium alkoxide with an ethylene alcohol-ether, and then chlorinating the magnesium complex. Catalyst components, catalysts, catalyst systems, polyolefin polymers and methods of making each are disclosed.
摘要:
It has been discovered that the amount of fluoropolymer additive used in a polyethylene resin affects the quality of finish of an article made with free surface polyethylene resins using chromium, Ziegler-Natta or metallocene catalysts. Reducing the amount of fluoropolymer increases the matte nature of the polymer finish, whereas increasing the amount of fluoropolymer increases the gloss nature of the finish. Introducing a peroxide or air in an increasing amount increases the long chain branching (LCB) of the polymer. Introducing an antioxidant in an amount to balance the peroxide amount can improve the melt strength of the polymer, and the amount of antioxidant is balanced with the amount of peroxide and/or air. The resultant polymer density ranges between about 0.960 and 0.962 g/cm3 inclusive, where the molecular weight distribution (MWD) of the polymer is greater than 3 and less than 6.
摘要翻译:已经发现,聚乙烯树脂中使用的含氟聚合物添加剂的量影响使用铬,齐格勒 - 纳塔或茂金属催化剂的用游离表面聚乙烯树脂制成的制品的表面光洁度。 减少含氟聚合物的量增加了聚合物涂饰的无光泽性质,而增加含氟聚合物的量增加了涂饰的光泽性质。 以增加的量引入过氧化物或空气增加聚合物的长链支化(LCB)。 引入抗氧化剂以达到平衡过氧化物量可以提高聚合物的熔体强度,并且抗氧化剂的量与过氧化物和/或空气的量平衡。 所得聚合物密度在约0.960至0.962g / cm 3之间,其中聚合物的分子量分布(MWD)大于3且小于6。
摘要:
The present invention provides an apparatus and a method for using the apparatus for safely training a motorcycle rider to perform a wheelie, either while moving or while stationary. The apparatus provides a safety system which prevents the motorcycle from tipping over backwards or sideways.
摘要:
Disclosed is a bimodal Ziegler-Natta catalyzed polyethylene, having a density of from 0.930 g/cc to 0.960 g/cc, and a molecular weight distribution of from 10 to 25, wherein an article formed therefrom has a PENT of at least 1500. Also disclosed is a method of preparing a tubular article including obtaining a bimodal polyethylene having a density of from 0.930 g/cc to 0.960 g/cc and a molecular weight distribution of from 10 to 25, and processing the polyethylene under conditions where a specific energy input (SEI) is less than 300 kW·h/ton, and wherein the article has a PENT of at least 1500. Further disclosed is a method for controlling the degradation of polyethylene including polymerizing ethylene monomer, recovering polyethylene, extruding the polyethylene, and controlling the degradation of polyethylene by measuring the SEI to the extruder and adjusting throughput and/or gear suction pressure keep SEI less than 300 kW·h/ton, and forming an article.