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Ab initio Hartree-Fock (HF) and density functional theory (DFT) calculations were carried out to determine the structural and electronic properties of the highest epoxygenated fullerenes C(60)O(30). For comparison, other fullerene oxides C(60)O(29), C(60)O(3), C(60)O(2) and C(60)O were also studied. The highly symmetrical I(h) structure of the parent C(60) is reserved in C(60)O(30) and C(60)O(30) was calculated to be a nonpolar molecule. It was demonstrated that C(60)O(30) should be more stable than other C(60) oxides such as C(60)O(29), C(60)O(3), C(60)O(2) and C(60)O. Compared with C(60), it is less possible for C(60)O(30) to accept or donate electrons from the reduced EAs and enhanced IPs. The IR active modes and harmonic vibrational frequencies of C(60)O(30) were also discussed. 相似文献
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The function of a protein is closely correlated to its subcellular location. Is it possible to utilize a bioinformatics method to predict the protein subcellular location? To explore this problem, proteins are classified into 12 groups (Protein Eng. 12 (1999) 107-118) according to their subcellular location: (1) chloroplast, (2) cytoplasm, (3) cytoskeleton, (4) endoplasmic reticulum, (5) extracellular, (6) Golgi apparatus, (7) lysosome, (8) mitochondria, (9) nucleus, (10) peroxisome, (11) plasma membrane and (12) vacuole. In this paper, the neural network method was proposed to predict the subcellular location of a protein according to its amino acid composition. Results obtained through self-consistency, cross-validation and independent dataset tests are quite high. Accordingly, the present method can serve as a complement tool for the existing prediction methods in this area. 相似文献
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Five reconstructed alpha-motoneurons (MNs) are simulated under physiological and morphological realistic parameters. We compare the resulting excitatory postsynaptic potential (EPSP) of models, containing voltage-dependent channels on the dendrites, with the EPSP of a passive MN and an active soma and axon model. In our simulations, we apply three different distribution functions of the voltage-dependent channels on the dendrites: a step function (ST) with uniform spatial dispersion; an exponential decay (ED) function, with proximal to the soma high-density location; and an exponential rise (ER) with distally located conductance density. In all cases, the synaptic inputs are located as a gaussian function on the dendrites. Our simulations lead to eight key observations. (1) The presence of the voltage-dependent channels conductance (g(Active)) in the dendrites is vital for obtaining EPSP peak boosting. (2) The mean EPSP peaks of the ST, ER, and ED distributions are similar when the ranges of G (total conductance) are equal. (3) EPSP peak increases monotonically when the magnitude of g(Na_step) (maximal g(Na) at a particular run) is increased. (4) EPSP kinetics parameters were differentially affected; time integral was decreased monotonically with increased g(Na_step), but the rate of rise (the decay time was not analyzed) does not show clear relations. (5) The total G can be elevated by increasing the number of active dendrites; however, only a small active area of the dendritic tree is sufficient to get the maximal boosting. (6) The sometimes large variations in the parameters values for identical G depend on the g(Na_step) and active dendritic area. (7) High g(Na_step) in a few dendrites is more efficient in amplifying the EPSP peak than low g(Na_step) in many dendrites. (8) The EPSP peak is approximately linear with respect to the MNs' R(N) (input resistance). 相似文献
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神经网络用于三元分子混合物密度与粘度的预测 总被引:5,自引:3,他引:2
以二元系实验为基础,利用反向转播算法训练神经网络,构造混合物组成,温度等与物性关系的模型,用于对4个三元混合物体系(1)邻二甲苯-间二甲苯-对二甲苯;(2)四氯化碳-环己烷-2-丙醇;(3)甲醇-丙酮-水;(4)水-甲醇-乙二醇的密度和5个三元混合物体系(1)信甲苯-间二甲苯-对二甲苯;(2)四氯化碳-环己烷-2-丙醇;(3)氯仿-2-丙醇-2-丁醇;(4)甲醇-丙酮-水;(5)乙醇-甲醇-水的粘 相似文献
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《Creativity & Innovation Management》1992,1(4):215-228
Book review in this Article Margaret Dale & Paul Iles (1992) Assessing Management Skills: A Guide to Competencies and Evaluation Techniques Dean Tjosvold (1991) Team Organization: An Enduring Competitive Advantage Brian Thomas (1992) Total Quality Training: The Quality Culture and Quality Training Michael J. Comer, Patrick M. Ardis, & David Price (1992) Bad Lies in Business, McGraw Hill Rosemary Dinnage (1992) The Ruffian on the Stair Peter Frost and Ralph Stablein (Eds) (1992) Doing Exemplary Research Janet Sayers (1992) Mothering Psychoanalysis, Penguin Books Vivian Walsh, Robin Roy, Margaret Bruce & Stephen Potter (1992) Winning by Design: Technology, Product Design & International Competitiveness David Megginson & Mike Pedler (1992) Self-Development: A Facilitators Guide Linda L. Putnam and Michael E. Roloff (1992) Communication and Negotiation Peter M. Senge (1990) The Fifth Discipline: The Art and Practice of The Learning Organization Keith Bradley (1992) Phone Wars, The Story of Mercury Communications Gordon J. Pearson (1992) The Competitive Organization Sonja A. Sackmann (1991) Cultural Knowledge in Organisations: Exploring the Collective Mind 相似文献
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A multivariable feedback system y(s)=G(s)x(s), x(s) = u(s)- F(s)y(s) is treated where G(s) ≜ (gkl (s)) is the transfer function matrix of a plant and F(s) ≜ diag(f1 (s),...,fn(s)) is that of a controller. A new bound for the transfer function hj (s) that relates yj (s) to uj (s) when fj (s)≡ 0 is given. The main result reads |hj (s)- gjj (s)| < aj(s) if |fk (s)-1+ gkk (s)| > ak (s) for k = 1,... ,n; k≠j. Here, A ≜ diag(a1 (s),...,an (s)) is a diagonal matrix which makes A-B a semi-M-matrix where B ≜ (bkl ) is given by bkk =0, bkl = |gkl (s)| (k≠l). A similar result is also obtained for the inverse transfer function. 相似文献
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A.C. Olson 《Computers & Geosciences》1977,3(3):539-545
An interactive computer program for graphical analysis has been developed by the U.S. Geological Survey. The program embodies five goals, (1) economical use of computer resources, (2) simplicity for user applications, (3) interactive on-line use, (4) minimal core requirements, and (5) portability. It is designed to aid (1) the rapid analysis of point-located data, (2) structural mapping, and (3) estimation of area resources. 相似文献
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田京京 《计算机工程与应用》2012,(25):39-41,60
根据路和星、圈的多重Mycielski图的结构性质,用穷染递推的方法,讨论了图Mn(Cm)和Mn(Pm),以及Mn(Sm)的邻点可区别I-全染色,得到了图Mn(Sm)和Mn(Pm)的邻点可区别I-全色数等于它们的最大度,图Mn(Cm)的邻点可区别I-全色数在m=4,5时等于它的最大度加1,其余情况等于它的最大度,即分别给出图Mn(Sm)和Mn(Cm)、Mn(Pm)一种染色方案。 相似文献
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Because the product of software engineering is not physical, physical laws do not form a suitable foundation. Instead, software engineering has had to evolve its principles based solely on observations of thousands of projects. The following are probably the 15 most important principles: (1) make quality number one priority; (2) high-quality software is possible; (3) give products to customers early; (4) determine the problem before writing requirements; (5) evaluate design alternatives; (6) use an appropriate process model; (7) use different languages for different phases; (8) minimize intellectual distance; (9) put technique before tools; (10) get it right before you make it faster; (11) inspect code; (12) good management is more important than good technology; (13) people are the key to success; (14) follow hype with care; and (15) take responsibility. An additional 15 software engineering principles are also listed 相似文献
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The development of injectable integrin α(v)β(3)/α(IIb)β(3) dual antagonists attracts much attention of research for treating of acute ischemic diseases in recent years. In this work, based on a dataset composed of 102 tricyclic piperazine/piperidine furnished dual α(v)β(3) and α(IIb)β(3) antagonists, a variety of in silico modeling approaches including the comparative molecular field analysis (CoMFA), comparative similarity indices analysis (CoMSIA), and molecular docking were applied to reveal the requisite 3D structural features impacting the biological activities. Our statistical results show that the ligand-based 3D-QSAR models for both the α(v)β(3) and α(IIb)β(3) studies exhibited satisfactory internal and external predictability, i.e., for the CoMFA models, results of Q(2)=0.48, R(ncv)(2)=0.87, R(pred)(2)=0.71 for α(v)β(3) and Q(2)=0.50, R(ncv)(2)=0.85, R(pred)(2)=0.72 for α(IIb)β(3) analysis were obtained, and for the CoMSIA ones, the outcomes of Q(2)=0.55, R(ncv)(2)=0.90, R(pred)(2)=0.72 for α(v)β(3) and Q(2)=0.52, R(ncv)(2)=0.88, R(pred)(2)=0.74 for α(IIb)β(3) were achieved respectively. In addition, through a comparison between 3D-QSAR contour maps and docking results, it is revealed that that the most crucial interactions occurring between the tricyclic piperazine/piperidine derivatives and α(v)β(3)/α(IIb)β(3) receptor ligand binding pocket are H-bonding, and the key amino acids impacting the interactions are Arg214, Asn215, Ser123, and Lys253 for α(v)β(3), but Arg214, Asn215, Ser123 and Tyr190 for α(IIb)β(3) receptors, respectively. Halogen-containing groups at position 15 and 16, benzene sulfonamide substituent at position 23, and the replacement of piperazine with 4-aminopiperidine of ring B may increase the α(v)β(3)/α(IIb)β(3) antagonistic activity. The potencies for antagonists to inhibit isolated α(v)β(3) and α(IIb)β(3) are linear correlated, indicating that similar interaction mechanisms may exist for the series of molecules. To our best knowledge this is the first report on 3D-QSAR modeling of these dual α(v)β(3)/α(IIb)β(3) antagonists. The results obtained should provide information for better understanding of the mechanism of antagonism and thus be helpful in design of novel potent dual α(v)β(3)/α(IIb)β(3) antagonists. 相似文献
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M. Sh. Levin 《Automation and Remote Control》2009,70(3):519-561
The significance of systems configurations has been increased in many applied domains (e.g., software, hardware, manufacturing systems, communication systems, supply chain systems, solving strategies, modular planning, material engineering and combinatorial chemistry). Generally, the following kinds of systems under configuration (reconfiguration) can be examined: (a) initial data/infomation (or row materials); (b) processing systems (machines, computers, algorithms); (c) resultant decisions (e.g., products, plans); (d) applied support systems (e.g., network systems, services); (e) requirements; and (f) standards. In the paper several system configuration problems are investigated: (i) searching for (selection of) a set (structure) of system components, (ii) searching for a set of compatible system components, (iii) allocation of system components, (iv) reconfiguration of a system as redesign of the system structure, (v) multi-stage design and redesign of system configuration, (vi) design or redesign of the system configuration for multi-product systems, and (vii) design of system hierarchy. Combinatorial optimization models (including multicriteria statements) are under examination: multiple choice problem, allocation problem, graph coloring problems, morphological clique problem (with compatibility of system components), multipartite clique and their modifications, spanning trees problems. 相似文献
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It is shown how to compute a differential representation for a multivariable linear system with disturbancesdot{x}(t)=Ax(t)+Bu(t)+ W_{x}w(t) y(t)=Cx(t)+ Eu(t)+ W_{y}w(t) . Explicit formulas forM_{y}(D) andM_{z}(D) in a differential equivalent representationP(D)z(t)=u(t)+M_{z}(D)w(t) y(t)=R(D)z(t)+M_{y}(D)w(t) are presented in this paper. 相似文献
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A pair of polynomial matrices,P(s) andQ(s) , is defined to be "externally skew prime" if and only if a solution,M(s), N(s) , to the polynomial matrix equationP(s)M(s)+N(s)Q(s)=I exists. It is shown thatP(s) andQ(s) are externally skew prime if and only ifQ(s)P(s)= bar{P}(s)R(s) withQ(s) andbar{P}(s) relatively left prime andP(s) andR(s) relatively right prime. This observation implies a new constructive procedure for determiningM(s) andN(s) whereP(s) andQ(s) are found to be externally skew prime andP(s) is nonsingular. A new procedure for obtaining solutions to the more general polynomial matrix equation,P(s)M(s)+N(s)Q(s)= V(s) , based on the notion of skew-prime polynomial matrices is also presented. A characterization of all solutions whenV(s)= I is also given, under appropriate assumptions, and then employed to determine a unique solution to this polynomial matrix equation. 相似文献
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Yan Xin Zhuang Hansen O. Knieling T. Wang C. Rombach P. Lang W. Benecke W. Kehlenbeck M. Koblitz J. 《Journal of microelectromechanical systems》2007,16(6):1451-1460
We have investigated the anti-stiction performance of self-assembled monolayers (SAMs) that were grown in vapor phase from six different organosilane precursors: CF3(CF2)5(CH2)2SiCl3 (FOTS), CF3(CF2)5(CH2)2Si(OC2H5)3 (FOTES), CF3(CF2)5(CH2)2Si(CH3)Cl2 (FOMDS), CF3(CF2)5(CH2)2Si(CH3)2Cl (FOMMS), CF3(CF2)7(CH2)2SiCl3 (FDTS), and CH3(CH2)17(CH2)2SiCl3 (OTS). The SAM coatings that were grown on silicon substrates were characterized with respect to static contact angle, surface energy, roughness, nanoscale adhesive force, nanoscale friction force, and thermal stability. The best overall anti-stiction performance was achieved using FDTS as precursor for the SAM growth, but all coatings show good potential for solving in-use stiction problems in microelectromechanical systems devices. 相似文献
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In this paper, a method of controlling a class of non-linear systems, x = F(x,t) (x element Rn) (or xk+1 = F(xk), (xk element Rn)), where F(x,t) (or F(xk)) is polynomial of degree m on x (or xk), is proposed. It can be proved that there exist solutions, x(t) (or xk), through specified open-loop (Hubler) action and a suitable non-linear closed-loop (feedback) action, which can be entrained to an arbitrary given goal, g(t) (or gk) element Rn, and the controlling basins of entrainment BE(g) (or BE(gk)) are global. 相似文献
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《IT Professional》2007,9(2):48-53
Software engineering has developed over the last few decades into a discipline of many diverse areas of interest. Examples include testing, programming, design, architecture, maintenance, metrics and evolution. Specialty conferences and publications proliferate, stay for a short time, and then disappear, while software engineering remains as nontraditional engineering - part craft, part art, and part logic. This article describes 13 challenges faced by software engineering research and practitioner community, and hints on what to do about them. The challenges include: (1) software quality, (2) return on investment, (3) process improvement, (4) metrics and measurement, (5) standards confusion, (6) standards interoperability, (7) legacy software, (8) testing stoppage criteria, (9) interoperability and composability, (10) operational profiles, (11) designing in, (12) product certification, (13) services. 相似文献
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Mehring GH Coates PA Brunel PC Luzio SD Owens DR 《Computer methods and programs in biomedicine》2002,68(2):161-176
The use of univariate and multivariate techniques to derive estimates of insulin sensitivity from the insulin modified FSIGT were investigated in 12 Type 2 diabetic subjects aged (mean+/-S.D.) 59+/-9.5 years and BMI 28.1+/-2.2 kg m(-2), who underwent both a FSIGT and an isoglycemic hyperinsulinemic clamp. Reproducibility of the FSIGT was tested in four patients on three separate occasions. FSIGT data were assessed by both univariate and multivariate techniques. The sensitivity index for the FSIGT ranged from 0.162 to 3.292 (mean 1.378) x 10(-4) x l min(-1) mU(-1) for the univariate approach and from 0.163 to 2.727 (mean 1.378) x 10(-4) x l min(-1) mU(-1) for the multivariate method. Mean S(Iclamp) was 44.41 x 10(-4) x l(-2) min(-1) x mU(-1) (range 22.0-77.92). The correlation of the insulin sensitivity indices between the clamp and the FSIGT was 0.51 (P=0.056) for the univariate and 0.67 (P=0.017) for the multivariate analyses. Repeated FSIGTs showed a lower variability for the multivariate than for the standard approach. 相似文献