检索结果-南通市图书馆

THE LIMITING CASE OF THIELE'S INTERPOLATING CONTINUED FRACTION EXPANSION

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2001年第4期19卷 433-444页

作者： Jie-qing Tan (Institute of Applied Mathematics, college of science and CAD/CG Division college of Computer & Information Hefei, university of technology, Hefei 230009, china) 中国科学技术大学安徽合肥 230009

By means of the determinantal formulae for inverse and reciprocal differences with coincident data points, the limiting case of Thiele's interpolating continued fraction expansion is studied in this paper and given numerical example shows that the limiting Thiele's continued fraction expansion can be determined once for all instead of carrying out computations for each step to obtain each convergent as done in [3].

关键词： Continued fraction Inverse difference Reciprocal difference Expansion.

File Assignment Policy in Network Storage System

在线全文

学校读者我要写书评

暂无评论

Wuhan university Journal of Natural sciences 2003年第4A期8卷 1075-1080页

作者： Cao Qiang, Xie Chang-sheng college of Computer science and technology, Huazhong university of science and technology, Wuhan 430074, Hubei, china college of Computer science and technology Huazhong University of Science and Technology Wuhan Hubei China

Network storage increase capacity and scalability of storage system, data availability and enables the sharing of data among clients. When the developing network technology reduce performance gap between disk and network, however, mismatched policies and access pattern can significantly reduce network storage performance. So the strategy of data placement in system is an important factor that impacts the performance of overall system. In this paper, the two algorithms of file assignment are presented. One is Greed partition that aims at the load balance across all NADs (Network Attached Disk). The other is Sort partition that tries to minimize variance of service time in each NAD. Moreover, we also compare the performance of our two algorithms in practical environment. Our experimental results show that when the size distribution (load characters) of all assigning files is closer and larger, Sort partition provides consistently better response times than Greedy algorithm. However, when the range of all assigning files is wider, there are more small files and access rate is higher, the Greedy algorithm has superior performance in compared with the Sort partition in off-line.

关键词： file assignment network storage network attached disk

A NOVEL INTERPRETATION OF CONCENTRATION DEPENDENCE OF VISCOSITY OF DILUTE POLYMER SOLUTION

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer science 2000年第1期18卷 57-67页

作者： Yan Pan Rong-shi Cheng college of Material science and Engineering, South china university of technology, Guangzhou 510641, china college of Chemistry and Chemical Engineering, Nanjing university, Nanjing 210093, china 华南理工大学广东广州

The concentration dependence of the reduced viscosity of dilute polymer solution is interpreted in the light of a new concept of the self-association of polymer chains in dilute solution. The apparent self-association constant is defined as the molar association constant divided by the molar mass of individual polymer chain and is numerically interconvertible with the Huggins coefficient. The molar association constant is directly proportional to the effective hydrodynamic volume of the polymer chain in solution and is irrespective of the chain architecture. The effective hydrodynamic volume accounts for the non-spherical conformation of a short polymer chain in solution and is a product of a shape factor and hydrodynamic volume. The observed enhancement of Huggins coefficient for short chain and branched polymer is satisfactorily interpreted by the concept of self-association. The concept of self-association allows us to predict the existence of a boundary concentration C-s(dynamic contact concentration) which divides the dilute polymer solution into two regions.

关键词： self-association polymer solution viscosity concentration dependence

b-DAZL:A novel gene in bovine spermatogenesis

在线全文

学校读者我要写书评

暂无评论

Progress in Natural science:Materials International 2008年第10期18卷 1209-1218页

作者： Qingbo Zhang~a Qifa Li~(a,*) Jiahuang Li~b Xinfu Li~a Zhenshan Liu~a Dawei Song~a Zhuang Xie~a ~a Laboratory of animal Reproductive Genetics and Molecular Evolution,college of animal science and technology,Nanjing Agriculture university,Nanjing 210095,china ~b Pharmaceutic Biotechnology Key Laboratory,college of Life science,Nanjing university,Nanjing 210093,china Laboratory of animal Reproductive Genetics and Molecular Evolution College of Animal Science and Technology Nanjing Agriculture University Nanjing 210095 China Pharmaceutic Biotechnology Key Laboratory College of Life Science Nanjing University Nanjing 210093 China

The DAZL gene plays an important role in *** and mutation of this gene has been frequently associated with the sterility in both vertebrates and ***,a cDNA containing the complete open reading frame of DAZL gene,which encodes putative RRM RNA-binding protein,was isolated from bovine tissues by *** isolated gene was referred to as ***-based location analysis showed that b-DAZL is located near the end of chromosome *** b-DAZL gene and its vertebrate homologue shared a high nucleotide similarity (90-94%) in the coding region and in the genomic organization,each consisting of 10 exons and 9 *** protein products contained a highly conserved RNA-binding motif,a unique DAZ repeat, and PUM2 and PABP interacting ***-PCR assay revealed that b-DAZL was expressed in the testis and ***,no signals were detected in the testes of sterile male *** microstructure of the testes of sterile males showed very few spermat- ocytes but mostly somatic *** observations are consistent with the typical phenotype of testes with defective DAZL expression. Subsequent gene detection studies indicated that transcription arrest might lead to a b-DAZL transcript defect in testes of cattle-yaks. Our results suggest that b-DAZL may be involved in spermatogenesis,and that transcription arrest of the gene is associated with male sterility in cattle-yaks.

关键词： Cattle-yak b-DAZL Male sterility Sequence analysis Expression profile

Noether-Form Invariance of Nonholonomic Controllable Mechanical Systems in Phase Space

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2007年第7期48卷 23-26页

作者： XIA Li-Li LI Yuan-Cheng college of Physics science and technology,china university of Petroleum,Dongying 257061,china college of Physics science and technology China University of Petroleum

In this paper,we study the Noether-form invariance of nonholonomic mechanical controllable systems inphase *** of motion of the controllable mechanical systems in phase space are *** definitionand the criterion for this system are presented.A new conserved quantity and the Noether conserved quantity deducedfrom the Noether-form invariance are *** example is given to illustrate the application of the results.

关键词： nonholonomic controllable mechanical system phase space Noether-form invariance conserved quantity

The structural analysis of fuzzy measures

在线全文

学校读者我要写书评

暂无评论

science china(Information sciences) 2011年第1期54卷 38-50页

作者： ZHANG Ling1,ZHANG Bo2 & ZHANG YanPing1 1 Computer science college,Anhui university,Hefei 230039,china 2State Key Lab of Intelligent technology & Systems Tsinghua National Lab for Information science & technology Information science & technology college,Computer science & technology,Tsinghua university,Beijing 100084,china Computer science college Anhui University State Key Lab of Intelligent technology & Systems Tsinghua National Lab for Information science & technology Information Science & Technology College Computer Science & Technology Tsinghua University

From quotient space based granular computing theory we explore the fuzzy measures of fuzzy sets. Based on the structural analysis of fuzzy sets,we present an"isotropism"*** this assumption we achieved the following insights:(1)the uniqueness of a fuzzy measure being isotropic on a finite complete semi-ordered set;(2)the necessary and suffcient condition of the isomorphism for fuzzy measure functions in fuzzy mathematics;(3)the necessary and suffcient condition that fuzzy measures have fuzzy and granular monotonicity;(4)under a certain assumption,the analytic expression for fuzzy *** results clarify the relationship between fuzzy measures and granular computing,reveal the essence of fuzzy measures,and provide a simple way of constructing fuzzy measures.

关键词： quotient space fuzzy set fuzzy measure rough set structural analysis

Influence of mesoscale topography on vortex intensity

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Progress in Natural science:Materials International 2008年第1期18卷 71-78页

作者： Zhexian Luo*,Yun Gao Remote Sensing college,Nanjing university of Information science and technology,Najing 210044,china Remote Sensing college Nanjing University of Information Science and Technology Najing 210044 China

The effect of mesoscale topography on multi-vortex self-organization is investigated numerically in this paper using a barotropic prim- itive equation model with topographic *** the initial field there are one DeMaria major vortex with the maximum wind radius rm of 80 km at the center of the computational domain,and four meso-b vortices in the vicinity of rm to the east of the major vortex center. When there is no topography present,the initial vortices self-organize into a quasi-final state flow pattern,i.e.a quasi-axisymmetric vor- tex whose intensity is close to that of the initial major ***,when a mesoscale topography is incorporated,the spatial scale of the quasi-final state vortex reduces,and the relative vorticity at the center of the vortex and the local maximum wind speed remarkably *** possible mechanism for the enhancement of the quasi-final state vortex might be that the negative relative vorticity lump, generated above the mesoscale topography because of the constraint of absolute vorticity conservation,squeezes the center of positive vorticity towards the mountain slope area,and thus reduces the spatial range of the major ***,because the total kinetic energy is basically conservative,the squeezing directly leads to the concentration of the energy in a smaller area,*** strengthening of the vortex.

关键词： Mesoscale topography Vortex Self-organization Intensity change

Research progress in the study of atmospheric pressure glow barrier discharge

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Progress in Natural science:Materials International 2007年第3期17卷 247-253页

作者： LI Xuechen, DONG Lifang and JIA Pengying (college of Physics science and technology, Hebei university, Baoding 071002, china) college of Physics science and technology Hebei University Baoding 071002 China

Atmospheric pressure glow barrier discharge (APGBD) can operate at high pressure, and so vacuum device is not necessary. Furthermore, the produced plasma by APGBD has moderate electron temperature and density besides good uniformity. Therefore, APGBD has extensive potential applications in industry and has been becoming a hot issue in the research of low temperature plasma. In this paper, the main problems in the study of atmospheric pressure glow discharge generated by dielectric barrier discharge, including the experimental setup, judging criterion, discharging conditions, physical mechanisms, and parameter diagnoses, are discussed, and further research prospects of APGBD are proposed.

关键词： atmospheric pressure glow discharge dielectric barrier discharge low temperature plasma.

ON THE LEAST SQUARES PROBLEM OF A MATRIXEQUATION

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 1999年第6期17卷 589-594页

作者： An-ping Liao(college of science, Hunan Normal university, Changsha 410081, china) 湖南师范大学理学院湖南长沙 410081

Least squares solution of F=PG with respect to positive semidefinite symmetric P is considered,a new necessary and sufficient condition for solvablity is given,and the expression of solution is derived in the some special cases. Based on the expression, the least spuares solution of an inverse eigenvalue problem for positive semidefinite symmetric matrices is also given.

关键词： least squares solution matrix equation inverse eigenvalue problem positive semidefinite symmetric matrix