检索结果-南通市图书馆

The regular representation and regular covariant representation of crossed products of Woronowicz C^(*)-algebras

在线全文

学校读者我要写书评

暂无评论

science China Mathematics 2005年第9期48卷 1245-1259页

作者： ZHANG Xiaoxia~(1,2. & GUO Maozheng~(1,3. 1. School of Mathematical sciences,Peking university,Beijing 100871,China 2. {2. of Mathematics,Yantai university,Yantai 2.4005,China 3. LMAM,Peking university,Beijing 100871,China School of Mathematical sciences Peking University Beijing China department of Mathematics Yantai University Yantai China LMAM Peking University Beijing China

In this paper,it is shown that the regular representation and regular covariant representation of the crossed products A×α G correspond to the twisted multiplicative unitary operators,where A is a Woronowicz C~*-algebra acted upon by a discrete group ***,it is also shown that the regular covariant C~*-algebra is the Woronowicz C~*-algebra which corresponds to a multiplicative ***,an explicit description of the multiplicative unitary operator for C(SU_q(2. )×α (?) is given in terms of those of the Woronowicz C~*-algebra C(SU_q(2. ) and the discrete group G.

关键词： multiplicative unitary operator, Woronowicz C*-algebra, crossed product.

Parabolic equation of the m-Laplacian with nonlinear boundary condition

在线全文

学校读者我要写书评

暂无评论

Chinese science Bulletin 1998年第11期43卷 905-908页

作者： WANG Shu+ 1, 2. WANG Mingxin 3. XIE Chunhong 1 1. department of Mathematics, Nanjing university, Nanjing 2.0093. China 2. department of Mathematics, Henan university, Kaifeng 475001, China 3. department of Applied Mathematics, Southeast university, department of Mathernntics Nanjing University Nanjing China department of Mathematics Henan University Kaifeng China department of Applied Mathematics Southeast University Nanjing China

The existence and nonexistence of global positive weak solutions of parabolic equation of the m-Laplician with nonlinear boundary condition are dealt with. The necessary and sufficient conditions on the existence of a... 详细信息

关键词： nonlinear boundary condition parabolic equation of m-Laplacian global solution blow-up.

ON THE ESTIMATIONS OF BOUNDS FOR DETERMINANT OF HADAMARD PRODUCT OF H-MATICES

在线全文

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2001年第4期19卷 365-370页

作者： Yao-tang Li (department of Mathemotics, Yuunan university,{2., China) Ji-cheng Li (department of Mathematics, Xian Jiaotong university, Xian 71049, China) 云南大学云南昆明 650091 西安交通大学陕西西安 710049

In this paper, some estimations of bounds for determinant of Hadamard product of H-matrices are given. The main result is the following: if A= (aij) and B=(bij) are nonsingular H-matrices of order n and ∏in=1, aiibii> 0, and Ak and Bk, k = 1, 2.…,n, are the k× k leading principal submatrices of A and B, respectively, then where M(Ak) denotes the comparison mains of Ak.

关键词： H-matrix Determinant Hadamard product.

Surface roughness and removal rate in magnetorheological finishing of a subsurface damage free surface

在线全文

学校读者我要写书评

暂无评论

Progress in Natural science:Materials International 2005年第6期15卷 538-544页

作者： CHENG Haobo1*, WANG Yingwei2. FENG Zhijing1 and CHENG Kai3.1. State Key Laboratory of Tribiology, Tsinghua university, Beijing 100084, China 2. {3. of Material {2.s, Changchun university of {2. and Technology, Changchun 13.02., China 3. Faculty of Information and Engineering Systems, City Campus, Leeds LS1 3.E, UK) State Key Laboratory of Tribiology Tsinghua University Beijing 100084 China department of Material sciences Changchun University of Science and Technology Changchun 130021 China Faculty of Information and Engineering Systems City Campus Leeds LS1 3HE United Kingdom

Based on computer-controlled optical surfacing, a new technique called magnetorheological finishing (MRF), is presented. The new technique combines the features of conventional loose abrasive machining with a wheel shaped polishing tool. The tool incorporates a host of features and has unprecedented fabricating versatility. The pre-polishing and fine polishing processes can be performed only by adjusting different parameters. The material removal function is studied theoretically and the results of simulation present a Gaussian distribution feature. Based on the established theoretical model, material removal rate experiments involving a parabolic mirror are designed and carried out to determine the effect of controllable parameters on size of the gap between the workpiece and the polishing wheel, rotating speed of the polishing wheel, concentration of volume fraction of non-magnetic particles and polishing time. Further experiments are carried out on the surface microstructure of the workpiece, the final surface roughness with an initial value of 10.98 nm reaches 1.2. nm root mean square (RMS) after 2. min of polishing. The subsurface damage experiment and the atomic force microscopy (AFM) measurement on the polished surface can also verify the feasibility of the MRF technique.

关键词： magnetorheological finishing surface roughness computer controlled optical surfacing subsurface damage removal function.

Variation in transboundary flow of Nujiang River and its correlation with summer monsoon under the effect of the Longitudinal Range-Gorge

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

science Bulletin 2007年第S2期 148-155页

作者： YOU WeiHong~(1+) GUO ZhiRong~(1,2. HE DaMing~3.1 department of atmospheric {2.s,School of Resource Environment and Earth {2.,yunnan university,kunming 650091,China 2.department of atmospheric {2.s,Nanjing Information Engineering university,Nanjing 2.0044,China 3.Asia International Rivers Center,yunnan university,kunming 650091,China

The relationship between the variations of the Nujiang River transboundary flow and the summer mon- soon activity under the topographical effect of the Longitudinal Range-Gorge（LRG）is *** study is based on statistical analysis of the observed river flow data,and their correlation with the reanalyzed U/V wind fields of the National Centers for Environment Prediction（NCEP）and the National Center for atmospheric Research（NCAR）,and the data of the Outgoing Longwave Radiation（OLR）of the National Oceanic and atmospheric Administration（NOAA）.It is concluded that the transboundary river flow is predominantly concentrated in the wet or rainy season（from May to October）,particularly in the summer or flood season（from June to August）.There is a clear tendency for the transboundary river flow to increase with time since 1970s,particularly apparent since *** to the topographical"east-west barrier and north-south corridor"effects of the LRG,the summer river flow variations are largely correlated with winds of the southerly and northerly at both high and low *** contrast, the river flow variations are apparently correlated wIth winds of the easterly and westerly only at the high altitudes,not at the low *** correlation between the OLR and the river flow varla- tions is also *** relationships are quantitatively described using two summer monsoon indices proposed in this *** index MI2.ncludes both dynamical and thermodynamical effects and givee a generally good representation of the transboundary river flow variations in the LRG region of the Nujiang River *** MI2.epresents stronger summer monsoon activity and higher transboundary river flow,while smaller MI2.uggests weaker monsoon circulation and lower water flow.

关键词： Longitudinal Range-Gorge(LRG) Nujiang River transboundary river flow summer monsoon monsoon index

A possible mode of the specific recognition of nucleic acids by proteins

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese science Bulletin 2001年第11期46卷 930-934页

作者： LI Xuqing & LIU Ciquandepartment of Computer science, {2.{3. of science and Technology, {2. 650041, China Laboratory of Cellular and Molecular Evolution, {2. Institute of Zoology, Chinese Academy of sciences, {2. 6502.3. China yunnan Observatory, Chinese Academy of sciences, {2. 650011, China 4. Modern Biological Center,{12., kunming 650091, China department of Computer science Kunming University of Science and Technology Kunming China yunnan Observatory Chinese Academy of Sciences Kunming China Laboratory of Cellular and Molecular Evolution Kunming Institute of Zoology Chinese Academy of Sciences Kunming China Modern Biological Center Yunnan University Kunming China

Seven sets of protein target sites, which occur in several gene promoters, have been analyzed. The results suggest that there is a possible mode of specific recognition of double-helical nucleic acids by proteins. This recognition mode is related to a special topological property of double-helical DNA, which is termed base spatial pattern (BSP) of DNA segment. BSP is the spatial topological property determined only by the spatial arrangement of the bases on double-helical DNA segment.

关键词： protein nucleic acids recognition base spatial pattern (BSP) target sites.

Characteristics of vertical ozone distribution in the lower troposphere in the Yangtze River Delta at Lin'an in the spring of 2.01

在线全文

学校读者我要写书评

暂无评论

science China Earth sciences 2005年第9期48卷 1519-1528页

作者： ZHENG Xiangdong1, CHAN Chuenyu2. CUI Hong2. QIN Yu3. CHAN Loyan2. ZHENG Yongguang3.& LEE Yusiang2.1. Chinese Academy of Meteorological sciences, Beijing 100081, China 2. department of Civil and Structural Engineering, Hong Kong Polytechnic {2., Hung Hom, Hong Kong, China 3. department of atmospheric sciences, Peking {2., Beijing 100871, China Chinese Academy of Meteorological sciences Beijing China department of Civil and Structural Engineering Hong Kong Polytechnic University Hung Hom Hong Kong China department of atmospheric {2.s Peking University Beijing China

We analyzed vertical distributions of ozone (O3. in the lower troposphere (< 5 km above ground) at Lin’an (119.75°E, 3..3.°N), Zhejiang Province using electrochemical concen- tration cell (ECC) ozonesonde data obta... 详细信息

We analyzed vertical distributions of ozone (O3. in the lower troposphere (3..3.°N), Zhejiang Province using electrochemical concen- tration cell (ECC) ozonesonde data obtained from February 2. to April 13. 2.01. The results showed that the vertical O3.distributions are controlled by metrological conditions and the char- acteristics of O3.profiles are related to those of wet bulb potential temperature and wind field. O3.below 2.km showed that the strongest variability and enhanced O3.mixing ratios were associated with easterly winds that blow pollutants from the upwind source region of the Yangtze River Delta (YRD) region. Vertical O3.profiles below 5 km can be grouped into 5 categories: (1) peak mixing ratio type, (2. well-mixed type, (3. layered-structure type, (4) episodic pollution type and (5) alti- tudinal increasing type. Vertical distributions of O3.affected by regional transport of polluted air masses were investigated. Transport of polluted air from high latitudes of northern China, ac- companying subsiding motion of air and stagnant atmospheric conditions are important factors that lead to high mixing ratios of O3.at Lin’an. The stagnant atmospheric conditions associated with a continental high pressure system and pollution plume transported from the YRD and cen- tral-eastern China also lead to regional accumulation of O3.and high O3.mixing ratio at Lin’an. Long-range transport of O3.and pollutants from the Pearl River Delta in South China and in-situ O3.formation also resulted in elevated O3.mixing ratios at around 1 km altitudes and layered O3.distribution in the lower troposphere.

关键词： vertical ozone distribution, lower troposphere, Yangtze River Delta, Lin'an.

Size distributions and magic number characteristics of cluster configurations formed during solidification processes of liquid metal Al

在线全文

学校读者我要写书评

暂无评论

science China(Technological sciences) 2006年第2期49卷 172-187页

作者： LIU Rangsu1, LIU Fengxiang1, DONG Kejun1, ZHENG Caixing1, LIU Hairong2. PENG Ping2.& LI Jiyong3.1. department of Physics, Hunan {3., Changsha 410082. China 2. department of Material {3. and Engineering, Hunan {3., Changsha 410082. China 3. department of Chemistry, Hunan {3., Changsha 410082. China department of Physics Hunan University Changsha China department of Material science and Engineering Hunan University Changsha China department of Chemistry Hunan University Changsha China

A molecular dynamics simulation study has been performed for a large systemconsisting of 100000 liquid metal Al atoms to investigate the formation and magic numbercharacteristics of the cluster configurations formed during the rapid solidification processes. Thecluster-type index method (CTIM) has been adopted to describe various types of clusterconfigurations. The results indicate that the icosahedral clusters (12.0 12.0) and theircombinations play the most important role in the rnicrostructure transitions during solidificationprocesses; for the cluster configurations of different levels formed by various combinations withdiffering numbers of basic clusters, their size distributions possess obvious magic number sequencewhich is in turn as 13.13., 19(2.), 2.-2.(2.), 3.0}3.(3.0}, 3.-40, 43.44, 48..., (those in bracket arethe corresponding value in liquid state); the magic numbers correspond to the peak value positionsof the cluster numbers for corresponding level formed with various combinations by 1, 2. 3. 4, 5, 6,7, ...basic clusters, respectively. This magic number sequence is in good agreement with theexperimental results obtained by Harris et al. At the same time, this simulation study also gives ascientific and reasonable explanation to these experimental results.

关键词： liquid metal, solidification processes, cluster configuration, magic numbers, computer simulation.

A study of two-dimensional magnetic polaron

在线全文

学校读者我要写书评

暂无评论

science China(Physics,Mechanics & Astronomy) 2006年第4期49卷 421-429页

作者： LIU Tao1, ZHANG Huaihong1, FENG Mang1,2.& WANG Kelin1,3.1. School of science, Southwest university of science and Technology, Mianyang 62.010, China 2. Wuhan Institute of Physics and Mathematics, Chinese Academy of sciences, Wuhan 43.070, China 3. department of Modern Physics, university of science and Technology of China, Hefei 2.002., China School of science Southwest University of Science and Technology Mianyang China Wuhan Institute of Physics and Mathematics Chinese Academy of Sciences Wuhan China department of Modern Physics University of Science and Technology of China Hefei China

By using the variational method and anneal simulation, we study in this paper the self-trapped magnetic polaron (STMP) in two-dimensional anti-ferromagnetic material and the bound magnetic polaron (BMP) in ferromagnetic material. Schwinger angular momentum theory is applied to changing the problem into a coupling problem of carriers and two types of Bosons. Our calculation shows that there are single-peak and multi-peak structures in the two-dimensional STMP. For the ferromagnetic material, the properties of the two-dimensional BMP are almost the same as that in one-dimensional case; but for the anti-ferromagnetic material, the two-dimensional STMP structure is much richer than the one-dimensional case.

关键词： self-trapped magnetic polaron, bound magnetic polaron, impurity potential, anti-ferromagnet.