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本文经对本地区部分前沿单位考查发现,分光光度计的错误预热方法较为严重为了纠正错误预热方法,保证分析结果准确可靠,提高分析工作者的业务素质,现将其错误预热方法予以分析,力求达到统一正确使用方法,改正错误的目的。 相似文献
84.
With the increasing emphasis on supply chain vulnerabilities, effective mathematical tools for analyzing and understanding appropriate supply chain risk management are now attracting much attention. This paper presents a stochastic model of the multi-stage global supply chain network problem, incorporating a set of related risks, namely, supply, demand, exchange, and disruption. We provide a new solution methodology using the Moreau–Yosida regularization, and design an algorithm for treating the multi-stage global supply chain network problem with profit maximization and risk minimization objectives. 相似文献
85.
This paper evaluates an algorithm for solving network flow optimization problems with quadratic cost functions. Strategies for fast implementation are discussed and the results of extensive numerical tests are given. The performance of the algorithm measured by CPU time is compared with that of the convex simplex method specialized for quadratic network programming. Performance of the two methods is analysed with respect to network size and density, and other parameters of interest. The algorithm is shown to perform significantly better on the majority of problems. We also show how the algorithm may be used to solve non-linear convex network optimization problems by the use of sequential quadratic programming. 相似文献
86.
Meir and Moon studied the distribution of the maximum degree for simply generated families of trees. We have sharper results for the special case of labelled trees. © 1994 John Wiley & Sons, Inc. 相似文献
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The effects of power ultrasound on four metal-nonmetal powdered systems: copper-sulphur iron-sulphur, zinc-sulphur and magnesium-sulphur in various solvents, such as hexane and carbon disulphide, are briefly examined here. For each system, a sonication time of 30 min was affected. The sonicated products are analysed by X-ray diffraction, X-ray fluorescence and atomic absorption spectrophotometry to determine their qualitative and quantitative compositions and the percentage yields of the products obtained are then compared and discussed. 相似文献
89.
分别掺有磷和硼的二氧化硅经γ辐照后产生多种顺磁性中心,ESR研究指出氧空穴O-主要稳定在杂质离子附近.O2-自由基稳定在Si离子上.F心的研究认为氧缺位俘获电子存在一个动态平衡过程. 相似文献
90.
B. S. Goh 《Journal of Optimization Theory and Applications》1997,92(3):581-604
Existing algorithms for solving unconstrained optimization problems are generally only optimal in the short term. It is desirable to have algorithms which are long-term optimal. To achieve this, the problem of computing the minimum point of an unconstrained function is formulated as a sequence of optimal control problems. Some qualitative results are obtained from the optimal control analysis. These qualitative results are then used to construct a theoretical iterative method and a new continuous-time method for computing the minimum point of a nonlinear unconstrained function. New iterative algorithms which approximate the theoretical iterative method and the proposed continuous-time method are then established. For convergence analysis, it is useful to note that the numerical solution of an unconstrained optimization problem is none other than an inverse Lyapunov function problem. Convergence conditions for the proposed continuous-time method and iterative algorithms are established by using the Lyapunov function theorem. 相似文献