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An equality on Hochschild homology groups

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Chinese science Bulletin 1997年第8期42卷 624-627页

作者： ZHANG Pu and LIU Shaoxue1. Department of Mathematics, University of science and technology of China, Hefei 2.002., China 2. Department of Mathematics, Beijing Normal University, Beijing 100875, China Department of Mathematics University of Science and Technology of China Hefei China Department of Mathematics Beijing Normal University Beijing China

LET A be finite-dimensional algebra over field k,and Ae the enveloping algebra of A,i.e.Ae=A kAop,where Aop is the opposite algebra of *** A-bimodule has a natural left Ae-module structure as follows:

关键词： finite-dimensional algebra Hochschild homology groups dimensions.

Large-scale information entropy analysis of important sites in mature and precursor miRNA sequences

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science China(Life sciences) 2009年第8期52卷 771-779页

作者： DU JiangFeng1,2.WU YongJun2.ZHANG YinXia3,WU Lei1,2.WANG XiaoLong3,TAO ShiHeng1,2.1 Bioinformatics Center,Northwest science and technology University of Agriculture,Yangling 712.00,China 2.College of Life sciences,Northwest science and technology University,Yangling 712.00,China 3 College of science,Northwest science and technology University,Yangling 712.00,China Bioinformatics Center Northwest Science and Technology University of Agriculture Yangling China College of Life sciences Northwest Science and Technology University Yangling China College of science Northwest Science and Technology University Yangling China

In order to find evidence of consistent sequence conservation or the base correlation degree in miRNA,some important sites in the sequences of reported miRNA and their precursors(pre-miRNA) were investigated via information entropy *** different groups of sites were obtained from special locations(head,tail) in miRNAs of different sources according to taxonomy(animal,plant and virus) and then analyzed by measuring the single base information redundancy(D1(L)) and the adjacent base related information redundancy(D2.L)).The results showed that D2.L) has more information than D1(L),though D1(L) changes roughly consistently with D2.L) in each *** pre-miRNAs are more conservative than those belonging to animals or *** addition,U is dominant in most sites compared with other *** was also found that in the middle of several groups,there were sites where miRNAs were cut down from pre-miRNAs by Enzyme Dicer which were significantly *** phenomenon shows that the conservatism is an aspect of the of miRNA and may be involved in the recognition and cutting by the *** results provided another perspective for understanding more about the primary structure of pre-miRNA.

关键词： miRNA conservative information entropy precursor evolution base correlation degree

Generalized Self-Adaptive Genetic Algorithms

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International Journal of Minerals,Metallurgy and Materials 2000年第1期14卷 72-75页

作者： Bin Wu Xuyan Tu Jian Wu Information Engineering School, University of science and technology Beijing, Beijing 100083, China Department of Information and Control Engineering, {2. Institute of technology, Mianyang 62.002. China Information Engineering School University of Science and Technology Beijing Beijing 100083 China Department of Information and Control Engineering Southwest Institute of Technology Mianyang 621002 China

In order to solve the problem between searching performance and convergence of genetic algorithms, a fast genetic algorithm generalized self-adaptive genetic algorithm (GSAGA) is presented. (1) Evenly distributed initial population is generated. (2. Superior individuals are not broken because of crossover and mutation operation for they are sent to subgeneration directly. (3) High quality im- migrants are introduced according to the condition of the population schema. (4) Crossover and mutation are operated on self-adaptation. Therefore, GSAGA solves the coordination problem between convergence and searching performance. In GSAGA, the searching per- formance and global convergence are greatly improved compared with many existing genetic algorithms. Through simulation, the val- idity of this modified genetic algorithm is proved.

关键词： generalized self-adaptive genetic algorithm initial population immigration fitness function

Tribological Properties of Dimpled Surface Alloying Layer on Carbon Steel

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Journal of Wuhan University of technology(Materials science) 2009年第2期24卷 218-222页

作者：万轶 Department of Materials science & Engineering Nanjing University of Science and Technology Department of Mechanical and Electrical Engineering Yingtian College

The effect of surface structure and coating on tribological properties of 45^# carbon steel disc was analyzed. A Nd：YAG laser was used to generate rnicrodirnples on steel surfaces. Dimples with diameter of 150 rn and depth of 50 rn were distributed in an orbicular array on disc surface. Then the alloying element Mo was sputtered to 45# carbon steel disc surface by means of double glow plasma technology. Diffusion Mo alloying layer with 30min thickness and high hardness up to 0.02. was formed on the disc surface. Tribological experiments of three types samples （smooth, texturing and texturing＋alloying） were conducted with a pin-on-disc tribometer. It is found that the dimpled-samples are most effective for reducing friction in comparison with smooth steel surthces, improving the lubricating state from boundary to hydrodynamic region.

关键词： laser surface texturing double glow plasma surface alloying technology carbon steel tribological performance lubricating state

Microstructure and Mechanical Properties of Martensitic Stainless Steel 6Cr15MoV

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Journal of Iron and Steel Research International 2012年第3期19卷 56-61页

作者： MA Dang-shen1, CHI Hong-xiao1,2. ZHOU Jian1, YONG Qi-long1,2.(1. Institute for Structural Materials, Central Iron and Steel Research Institute, Beijing 100081, China 2. Faculty of Materials science and Engineering, Kunming University of science and {2., Kunming 650093, Yunnan, China) Institute for Structural Materials Central Iron and Steel Research Institute Beijing China Faculty of Materials science and Engineering Kunming University of Science and Technology Kunming Yunnan China

Martensitic stainless steel containing Cr of 12. to 18%（mass percent） are common utilized in quenching and tempering processes for knife and cutlery steel. The properties obtained in these materials are significantly influ- enced by matrix composition after heat treatment, especially as Cr and C content. Comprehensive considered the hardness and corrosion resistance, a new type martensitic stainless steel 6Crl5MoV has been developed. The effect of heat treatment processes on microstructure and mechanical properties of 6Crl5MoV martensitic stainless steel is emphatically researched. Thermo-Calc software has been carried out to thermodynamic calculation; OM, SEM and TEM have been carried out to microstructure observation; hardness and impact toughness test have been carried out to evaluate the mechanical properties. Results show that the equilibrium carbide in 6Cr15MoV steel is M2. C6 car- bide, and the M2. C6 carbides finely distributed in annealed microstructure. 6Crl5MoV martensitic stainless steel has a wider quenching temperature range, the hardness value of steel 6Cr15MoV can reach to HRC 60.8 to HRC 61.6 when quenched at 1 060 to 1 100 ℃. Finely distributed carbides will exist in quenched microstructure, and effectively inhabit the growth of austenite grain. With the increasing of quenching temperature, the volume fraction of undis- solved carbides will decrease. The excellent comprehensive mechanical properties can be obtained by quenched at 1 060 to 1 100℃ with tempered at 100 to 150 ℃, and it is mainly due to the high carbon martensite and fine grain size. At these temperature ranges, the hardness will retain about HRC 59.2.to HRC 61.6 and the Charpy U-notch impact toughness will retain about 17.3 to 2. J. A lot of M2.C6 carbides precipitated from martensite matrix, at the same time along the boundaries of martensite lathes which leading to the decrease of impact toughness when tempered at 500 to 540 ℃. The MaC precipitants also existed in the martensite mat

关键词： martensitic stainless steel microstructure mechanical property

A New Multisoliton Solution to (2.1)-Dimensional KdV Equation

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Communications in Theoretical Physics 2004年第5期41卷 669-670页

作者： PENG Yan-Ze~(1,2. 1 Department of Mathematics,Huazhong University of science and technology,Wuhan 430074,China2.Department of Mathematics and Physics,Henan University of science and technology,Luoyang 471003,China Department of Mathematics Huazhong University of Science and Technology Wuhan 430074 China Department of Mathematics and Physics Henan University of Science and Technology Luoyang 471003 China

A new multisoliton solution to the(2.1)-dimensional KdV equation is obtained by means of the truncatedPainleve expansion method and a direct ansatz *** new exact solution is periodic in the propagating directionx and exponentially decaying in y and thus it is called periodic solitons.A typical spatial structure of it is illustrated bythe figures.

关键词： (2.1)-dimensional KdV equation periodic solitons truncated Painleve expansion method

A low frequency piezoelectric power harvester using a spiral-shaped bimorph

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science China(Physics,Mechanics & Astronomy) 2006年第6期49卷 649-659页

作者： HU Yuantai1,2.HU Hongping2.& YANG Jiashi3 1. Institute of Mechanics and Sensing technology,Central South University,Changsha 410083,China 2. Department of Mechanics,Huazhong University of science and technology,Wuhan 430074,China 3. Department of Engineering Mechanics,University of Nebraska,Lincoln,NE 68588-052.,USA Institute of Mechanics and Sensing technology Central South University Changsha China Department of Mechanics Huazhong University of Science and Technology Wuhan China Department of Engineering Mechanics University of Nebraska Lincoln USA

We propose a spiral-shaped piezoelectric bimorph power harvester operating with coupled flexural and extensional vibration modes for applications to low frequency energy sources. A theoretical analysis is performed and the computational results show that the spiral structure has relatively low operating frequency compared to beam power harvesters of the same size. It is found that to optimize the performance of a piezoelectric spiral-shaped harvester careful design is needed.

关键词： spiral-shaped bimorph,piezoelectric harvester,power density.

Early Hydration of Composite Cement with Thermal Activated Coal Gangue

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Journal of Wuhan University of technology(Materials science) 2010年第1期25卷 162-166页

作者：郭伟 Department of Material Engineering Yancheng Institute of Technology Institute of Material science and Engineering Nanjing University of Technology

Composite cement samples were prepared by mixing clinker, gypsum with burnt coal gangues which was calcined at various temperatures. The mechanical strength and Ca（OH）2.content in the cement paste were tested, and the paste composition and microstructure were analyzed by thermogravimetry-differential thermal analysis （TG-DSC）, X-ray diffraction（XRD）, scanning electronic microscopy （SEM） and pore structure analysis. Results demonstrate that the thermal activated coal gangue could accelerate the early hydration of cement clinker obviously, which promotes the gangue hydration itself. The early hydrated products of the cement are C-S-H gel, Ca（OH）2.and AFt. The cement with 30% （in mass） the gangue exhibits higher mechanical strength, and among all the cement samples the one with the gangue burnt at 700 ℃ displays the highest hydration rate, mechanical strength, the most gel pores and the lowest total porosity.

关键词： blended cement hydration microstructure hydration product

Topological chirality and achirality of the closed circular DNAs

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Chinese science Bulletin 1997年第20期42卷 1705-1708页

作者： QIU Wenyuan and XIN Houwen1. Department of Chemical Physics, University of science and technology of China, Hefei 2.002., China 2. Department of Chemistry, Lanzhou University, Lanzhou 730000, China Department of Chemical Physics University of Science and Technology of China Hefei China Department of Chemistry Lanzhou University I anzhou China

THE study of the relations between the topological structure and its function is one of the focus-es in modern chemistry and life science. In this note we set up a topological model to de-scribe the ccDNAs on the basis of Seifert construction in knot theory. Our model for theccDNAs helps to determine whether a structure is topologically chiral or achiral. This is one ofthe fundamental biological problems.

关键词： DNA topology knot theory topologiesl chirality topological achirality.