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91.
C. D. Habben 《无机化学与普通化学杂志》1991,606(1):229-232
Synthesis of Boron-Sulfur(IV)-Nitrogen Heterocycles The reaction of bis(lithio.tert.-butylamino)phenylborane with tert.-butyldichlorosulfimide and bischlorodimethylsilylsulfodiimide respectively leads to four- or eight-membered heterocycles. The disulfanebridge of one dithiazadiborolidine can be replaced by the ? N?S?N-sequence to yield a Thiatriazadiborine. 1H, 11B, 13C-NMR, mass spectra, and analytical data are reported and discussed. 相似文献
92.
廖开顺 《厦门理工学院学报》2002,10(4):94-96
对高校新教师应进行备课指导,要求他们层层了解课程的背景材料,懂得备课的几种形式和基本规范,注意收集教学反馈情况,逐步提高教学艺术水平。 相似文献
93.
环境污染治理的经济分析模型 总被引:3,自引:0,他引:3
李连华 《五邑大学学报(自然科学版)》2003,17(2):9-12
环境污染的治理是化工、制造等企业的一项重要经济活动,如何进行有关的决策分析是困扰企业的一个难题.在分析环境成本性态的基础上,设计了排污费和排污权交易两种制度下的经济分析模型,为企业进行相关决策提供了理论框架和依据、 相似文献
94.
C. Bogani M. G. Gasparo A. Papini 《Journal of Optimization Theory and Applications》2007,134(1):47-59
We propose a pattern search method to solve a classical nonsmooth optimization problem. In a deep analogy with pattern search
methods for linear constrained optimization, the set of search directions at each iteration is defined in such a way that
it conforms to the local geometry of the set of points of nondifferentiability near the current iterate. This is crucial to
ensure convergence. The approach presented here can be extended to wider classes of nonsmooth optimization problems. Numerical
experiments seem to be encouraging.
This work was supported by M.U.R.S.T., Rome, Italy. 相似文献
95.
Adam B. Levy 《Mathematical Programming》2007,110(3):615-639
Numerical methods for solving constrained optimization problems need to incorporate the constraints in a manner that satisfies
essentially competing interests; the incorporation needs to be simple enough that the solution method is tractable, yet complex
enough to ensure the validity of the ultimate solution. We introduce a framework for constraint incorporation that identifies
a minimal acceptable level of complexity and defines two basic types of constraint incorporation which (with combinations)
cover nearly all popular numerical methods for constrained optimization, including trust region methods, penalty methods,
barrier methods, penalty-multiplier methods, and sequential quadratic programming methods. The broad application of our framework
relies on addition and chain rules for constraint incorporation which we develop here. 相似文献
96.
Gerhard Starke 《Numerische Mathematik》1997,78(1):103-117
Summary. The convergence rate of Krylov subspace methods for the solution of nonsymmetric systems of linear equations, such as GMRES
or FOM, is studied. Bounds on the convergence rate are presented which are based on the smallest real part of the field of
values of the coefficient matrix and of its inverse. Estimates for these quantities are available during the iteration from
the underlying Arnoldi process. It is shown how these bounds can be used to study the convergence properties, in particular,
the dependence on the mesh-size and on the size of the skew-symmetric part, for preconditioners for finite element discretizations
of nonsymmetric elliptic boundary value problems. This is illustrated for the hierarchical basis and multilevel preconditioners
which constitute popular preconditioning strategies for such problems.
Received May 3, 1996 相似文献
97.
We extend an earlier method for solving kinetic boundary layer problems to the case of particles moving in aspatially inhomogeneous background. The method is developed for a gas mixture containing a supersaturated vapor and a light carrier gas from which a small droplet condenses. The release of heat of condensation causes a temperature difference between droplet and gas in the quasistationary state; the kinetic equation describing the vapor is the stationary Klein-Kramers equation for Brownian particles diffusing in a temperature gradient. By means of an expansion in Burnett functions, this equation is transformed into a set of coupled algebrodifferential equations. By numerical integration we construct fundamental solutions of this equation that are subsequently combined linearly to fulfill appropriate mesoscopic boundary conditions for particles leaving the droplet surface. In view of the intrinsic numerical instability of the system of equations, a novel procedure is developed to remove the admixture of fast growing solutions to the solutions of interest. The procedure is tested for a few model problems and then applied to a slightly simplified condensation problem with parameters corresponding to the condensation of mercury in a background of neon. The effects of thermal gradients and thermodiffusion on the growth rate of the droplet are small (of the order of 1%), but well outside of the margin of error of the method. 相似文献
98.
《厦门大学学报(自然科学版)》2002,(Z1)
With the application of the principle of PDCA, and dr awing on the experience of the process methods of the ISO9000 and the system met hods of management, the author analyses the basic requirement to fulfill quality management system in enterprises. Then the author inquires into the procedure t o establish the efficiency quality management system. Finally four stages (plan, do, check, action) and eight steps (decision, plan, analyze, design, do, check, improve, fulfill) are put forward to fulfill qualit... 相似文献
99.
100.
The many facets of linear programming 总被引:1,自引:0,他引:1
Michael J. Todd 《Mathematical Programming》2002,91(3):417-436
We examine the history of linear programming from computational, geometric, and complexity points of view, looking at simplex,
ellipsoid, interior-point, and other methods.
Received: June 22, 2000 / Accepted: April 4, 2001?Published online October 2, 2001 相似文献