检索结果-南通市图书馆

The Innovation 2023年第4期4卷 27-28页

作者： Tao Huang Yixue Li Bio-Med Big Data Center CAS Key Laboratory of Computational BiologyShanghai Institute of Nutrition and HealthUniversity of Chinese Academy of SciencesChinese Academy of SciencesShanghai 200031China Key Laboratory of Systems Health Science of Zhejiang Province School of Life ScienceHangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhou 310024China Guangzhou Laboratory Guangzhou 510005China School of Life Sciences and Biotechnology Shanghai Jiao Tong UniversityShanghai 200240China Collaborative Innovation Center for Genetics and Development Fudan UniversityShanghai 200433China

The sequence-structure-function paradigm of protein is the basis of molecular biology.What is the underlying mechanism of such sequence and structure/function corresponding relationship?We reviewed the methods for protein representation and protein design.With these protein representation models,we can accurately predict many properties of proteins,such as stability and binding affinity.

关键词： representation function design.

Uniform design. for mixture-amount experiments and for mixture experiments under order restrictions

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Mathematics 1999年第5期42卷 456-470页

作者：田国梁方开泰 Institute of Applied Mathematics Chinese Academy of Sciences Beijing China Hong Kong Baptist University Hong Kong and Institute of Applied Mathematics Chinese Academy of Sciences Beijing China

With order statistics of the uniform distribution on [0, 1], exponential and beta distributions, a stochastic representation is obtained for the uniform distribution over various domains, where A-type domains are closely associated with reliability growth analysis, order restricted statistical inference and isotonic regression theory, V-type domains are connected with the mixture-amount experiments, and T-type domains are well related to mixture experiments. With these stochastic representations, the corresponding uniform distribution and number-theoretic nets can be generated. This approach seems to be new and is called order statistics method. Some examples on reliability growth analysis and experimental design.are presented.

关键词： discrepancy isotonic restriction Monte Carlo optimization multivariate distribution uniform design.

Phase relationships and materials design.in the Ln-Si-Al-O-N system

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2000年第3期43卷 225-232页

作者：严东生孙维莹 The State Key Laboratory on High Performance Ceramics and Superfine Microstructure Shanghai Institute of Ceramics Chinese Academy of Sciences Shanghai 200050 China

Subsolidus phase relationships in the system Ln2O3-Si3N4-AlN-Al2O3, where Ln represents Nd, Sm and Dy, were summarized, with emphasis on the region involving α-sialon, β-sialon and AlN-polytypoid phases. This information is further used in design.ng the compatible matrix phases of sialon materials with desirable properties. Examples were provided to illustrate the advantage of such a basic approach to materials design.

关键词： Si3N4 β-sialon P-sialon AlN-polytypoids Ln2O3 phase equilibrium composition design.

Construction of optimal supersaturated design. by the packing method

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2004年第1期47卷 128-143页

作者： FANG Kaitai GE Gennian LIU Minqian Department of Mathematics Hong Kong Baptist University Hong Kong China Department of Mathematics Zhejiang University Hangzhou 310027 China Department of Statistics Nankai University Tianjin 300071 China

A supersaturated design.is essentially a factorial design.with the equal occurrence of levels property and no fully aliased factors in which the number of main efits potential in factor screening experiments. A packing design.is an important object in combinatorial design.theory. In this paper, a strong link between the two apparently unrelated kinds of design. is shown. Several criteria for comparing supersaturated design. are proposed, their properties and connections with other existing criteria are discussed.A combinatorial approach, called the packing method, for constructing optimal supersaturated design. is presented, and properties of the resulting design. are also investigated.Comparisons between the new design. and other existing design. are given, which show that our construction method and the newly constructed design. have good properties.

关键词： Kirkman triple systems, orthogonality, packing design. resolvability, supersaturated design.

Interface conjunction factors of thermal barrier coatings and the relationship between factors and composition

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2003年第3期46卷 234-244页

作者：李志林徐惠彬宫声凯 College of Materials Science and Engineering Beijing University of Chemical Technology 2College of Materials Science and Engineering Beijing University of Aeronautics and Astronautics Beijing 100083 China College of Materials Science and Engineering Beijing University of Aeronautics and Astronautics

In thermal barrier coatings (TBC), ceramics is covered on the metal matrix as coatings in order to raise its temperature endurance. Today most of the TBCs are of the double-layer-struc- ture of Ni base heat-resistant alloy matrix + the bonding layer of MCrAlY alloy (M = Ni, Co, Ni + Co) + ZrO2. In this paper, the concept of interface conjunction factor (ICF) in the biphase interface of alloys is expanded to coatings. The ICFs of the interface between the ceramics and the bonding layers with various compositions, such as the electron density r, the electron density difference Dr, and the number of atom state group which keeps the electron density continuous s are calculated. From the calculation results, the following estimations can be deduced. When Al content is less than 6 wt% it improves the mechanical properties of the coatings; when the content is 6 wt%—12 wt% it will not worsen the properties; when the content is greater than 12 wt% it will have disad-vantageous effect. The estimations accord well with the experiment results of the properties and the service time of the coatings. Therefore the concept of ICF has the same important meaning in coatings, and the valence electron structure of the interface can be a possible theoretical guide for the content optimization of TBCs.

关键词： thermal barrier coatings, interface, valence electron structure, composition design.

Finite Element Investigation of Flow Field Below Asymmetric Drill Bits for Reverse Circulation in Drilling Tight Oil and Gas Reservoirs

在线全文

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & Sciences 2019年第10期121卷 105-122页

作者： Yi Luo Erxiu Shi Yin Feng Boyun Guo Liehui Zhang State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum UniversityChengduChina University of Louisiana at Lafayette LafayetteLAUSA.

Development of unconventional tight oil and gas reservoirs such as shale pays presents a huge challenge to the petroleum industry due to the naturally low permeability of shale formations and thus low productivity of oil and gas wells.Shale formations are also vulnerable to the contamination of the water in the drilling and completion fluids,which further reduces reservoir permeability.Although gas-drilling(drilling with gas)has been used to address the issue,several problems such as formation water influx,wellbore collapse,excessive gas volume requirement and hole cleaning in horizontal drilling,still hinder its application.A new technique called gas-lift drilling has recently been proposed to solve these problems,but the optimal design.of drilling operation requires a thorough investigation of fluid flow field below the asymmetric drill bits for evaluating the fluid power needed to clean the bottom hole.Such an investigation is conducted in this work based on the Finite Element Method(FEM)implemented in an open source computational framework,FEniCS.Pressure and flow velocity fields were computed for three design. of drill bit face characterized by radial bit blades and one eccentric orifice of discharge.One of the design. is found superior over the other two because it generates relatively uniform flow velocities between blades and provides a balanced fluid power needed to clean all the bit teeth on each bit blade.To quantify the capability of borehole cleanup presented by three drill bit design.,the energy per unit volume is calculated in each region of drill bit and compared with the required value suggested by the literature.In addition,the developed FEM model under FEniCS framework provides engineers an accurate tool for optimizing drill bit design.for efficiently gas-lift drilling unconventional tight oil and gas reservoirs.

关键词： Gas-lift drilling reverse circulation unconventional reservoirs bit design.

Minimal regular 2-graphs and applications

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Mathematics 2006年第2期49卷 158-172页

作者： FAN Hongbing, LIU Guizhen & LIU Jiping Department of Physics and Computer Science, Wilfrid Laurier University, Waterloo, ON., N2L 3C5 Canada School of Mathematics and System Science, Shandong University, Jinan 250100, China Department of Mathematics and Computer Science, University of Lethbridge, Lethbridge, AB., T1K 3M4, Canada Department of Physics and Computer Science Wilfrid Laurier University Waterloo Canada School of Mathematics and System Science Shandong University Jinan China Department of Mathematics and Computer Science University of Lethbridge Lethbridge Canada

A 2-graph is a hypergraph with edge sizes of at most two. A regular 2-graph is said to be minimal if it does not contain a proper regular factor. Let f2(n) be the maximum value of degrees over all minimal regular 2-graphs of n vertices. In this paper, we provide a structure property of minimal regular 2-graphs, and consequently, prove that f2(n) = n+3-i/3where 1 ≤i≤6, i=n (mod 6) andn≥ 7, which solves a conjecture posed by Fan, Liu, Wu and Wong. As applications in graph theory, we are able to characterize unfactorable regular graphs and provide the best possible factor existence theorem on degree conditions. Moreover, f2(n) and the minimal 2-graphs can be used in the universal switch box design., which originally motivated this study.

关键词： graph regular factor 2-graph switch box design.

Some results on resolvable incomplete block design.

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2005年第4期48卷 503-512页

作者： LIU Minqian & FANG Kaitai Department of Statistics, Nankai University, Tianjin 300071, China Department of Mathematics, Hong Kong Baptist University, Hong Kong, China Department of Statistics Nankai University Tianjin China Department of Mathematics Hong Kong Baptist University Hong Kong China

This paper is concerned with the uniformity of a certain kind of resolvable incomplete block (RIB for simplicity) design.which is called the PRIB design.here. A sufficient and necessary condition is obtained, under which a PRIB design.is the most uniform in the sense of a discrete discrepancy measure, and the uniform PRIB design.is shown to be connected. A construction method for such design. via a kind of U-type design. is proposed, and an existence result of these design. is given. This method sets up an important bridge between PRIB design. and U-type design..

关键词： block design. discrepancy, orthogonal array, supersaturated design. U-type design.

Comparison of two design.methods of aerodynamic biobjectives for airfoil and wing shapes

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2004年第2期47卷 203-215页

作者： ZHU Ziqiang FU Hongyan LIU Hang WANG Xiaolu Beijing University of Aeronautics and Astronautics Beijing 100083 China Beijing University of Aeronautics and Astronautics Beijing 100083 China Beijing University of Aeronautics and Astronautics Beijing 100083 China Beijing University of Aeronautics and Astronautics Beijing 100083 China

A simplified adaptive wing, which deflects its leading edge and trailing edge flaps to vary its shape, is calculated to investigate the potential aerodynamic gains and compared with a biobjective optimization (BO) wing in the present paper. In subsonic-transonic flights the deflection angle of a flap is determined through optimization using a deterministic method . In supersonic flight the flaps are not deflected due to the requirement of having a minimum drag. For comparison the aerodynamic characteristics of a BO airfoil and wing is calculated. A parallel genetic algorithm is used in BO. Euler equations served as governing equations in flow field calculation. Numerical results in both 2D (airfoil) and 3D (wing) cases show that aerodynamic performances of the two design.airfoils and wings are much better than those of the original ones, with the adaptive design.one the best.

关键词： simplified adaptive wing, biobjective optimization, airfoil and wing design.

Birefringent non-polarizing thin film design

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2005年第1期48卷 61-69页

作者： QI Hongji HONG Ruijin HE Hongbo SHAO Jianda FAN Zhengxiu Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences Shanghai 201800 China Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences Shanghai 201800 China Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences Shanghai 201800 China Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences Shanghai 201800 China Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences Shanghai 201800 China

In this paper, 2×2 characteristic matrices of uniaxially anisotropic thin film for extraordinary and ordinary wave are deduced at oblique incidence. Furthermore, the reflectance and transmittance of thin films are calculated separately for two polarizations, which provide a new concept for design.ng non-polarizing thin films at oblique incidence. Besides, using the multilayer birefringent thin films, non-polarizing design., such as beam splitter thin film at single wavelength, edge filter and antireflection thin film over visible spectral region are obtained at oblique incidence.

关键词： birefringent thin film, non-polarization, design.