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991.
分析了以Na2CO3-NaHCO3混合溶液为淋洗液,离子色谱法测定碱性样品时,色谱负峰产生的原因。通过计算和试验,采用在样品中加入适量NaHCO3进行中和的方法,解决了负峰影响HCOO^-测定的问题。 相似文献
992.
A new method is presented for the calculation of octanol/water partition coefficients. On the basis of summation of atomic contributions, our algorithm, namely; XLOGP, also incorporate correction factors into the calculation. Multivariate regression analysis was performed on a training database of 1831 organic compounds with diverse structures to give the final model. The correlation coefficients for the whole set fitting is 0.968 and the standard deviation is 0.37. The result shows that our model is accurate enough for logP estimation in QSAR studies. Compared to other similar approaches, our method gives better results and is more convenient to use. 相似文献
993.
介绍用UV光电法测量MCP电子增益时,UV透过金薄膜的附加输出给测量带来的影响,给出了实验结果并进行初步分析,最后指出确保增益测量结果可靠性的途径。 相似文献
994.
New Type of Generalized Vector Quasiequilibrium Problem 总被引:1,自引:0,他引:1
J. Y. Fu S. H. Wang Z. D. Huang 《Journal of Optimization Theory and Applications》2007,135(3):643-652
In this paper, we introduce a new type of vector quasiequilibrium problem with set-valued mappings and moving cones. By using
the scalarization method and fixed-point theorem, we obtain its existence theorem. As applications, we derive some existence
theorems for vector variational inequalities and vector complementarity problems.
This work was supported by the National Natural Science Foundation of China. The authors are grateful to Professor X.Q. Yang
and the referees for valuable comments and suggestions improving the original draft. 相似文献
995.
F. Fu L.-H. Liu L. Wang 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,56(4):367-372
We focus on the heterogeneity of social networks and its
role to the emergence of prevailing cooperators and sustainable
cooperation. The social networks are representative of the
interaction relationships between players and their encounters in
each round of games. We study an evolutionary Prisoner's Dilemma
game on a variant of Newman-Watts small-world network, whose
heterogeneity can be tuned by a parameter. It is found that
optimal cooperation level exists at some intermediate topological
heterogeneity for different temptations to defect. That is,
frequency of cooperators peaks at a certain specific value of
degree heterogeneity — neither the most heterogeneous case nor
the most homogeneous one would favor the cooperators. Besides, the
average degree of networks and the adopted update rule also affect
the cooperation level. 相似文献
996.
With the continuous improvement of computational performance, vehicle structural design has been addressed using computational methods, resulting in more efficient development of new vehicles. Most simulation-based optimization approaches generate deterministic optimal designs without considering variability effects in modeling, simulation, and/or manufacturing. One of the main reasons for this omission is due to the fact that the computing time of a single crash analysis for vehicle structural design still requires significant computing time using a state-of-the-art computer. This calls for the development and implementation of an efficient optimization under uncertainty method. In this paper, a new integrated stochastic optimization method, which combines the advantages of metamodeling techniques and Better Optimization of Nonlinear Uncertain Systems (BONUS), is developed for vehicle side impact design. Nonlinear metamodels are built by using a stepwise regression method to replace the expensive computational model and BONUS is employed to obtain optimal designs under uncertainty. A benchmark problem for vehicle safety design is used to demonstrate the method. The main goal of this case study is to maintain or enhance the vehicle side impact test performance while minimizing the vehicle weight under various uncertainties. 相似文献
997.
This paper presents a new approach to multiobjective optimization based on the principles of probabilistic uncertainty analysis. At the core of this approach is an efficient nonlinear multiobjective optimization algorithm, Minimizing Number of Single Objective Optimization Problems (MINSOOP), to generate a true representation of the whole Pareto surface. Results show that the computational savings of this new algorithm versus the traditional constraint method increase dramatically when the number of objectives increases. A real world case study of multiobjective optimal design of a best available control technology for Nitrogen Oxides (NOx) and Sulfur Oxides (SOx) reduction illustrates the usefulness of this approach. 相似文献
998.
Lang Tao SHEN Ting YANG Hong Yu LI Ji HU Zhi Fu LUO National Isotope Center of Engineering Technology China Institute of Atomic Energy Beijing P. O. Box 《中国化学快报》2006,(6)
Iron is indispensable for almost all life forms1. Under iron-deficient environments, microorganisms secrete siderophores to chelate ferric ions and then, transport ferric ions into cells by specific receptor recognitions2,3. Siderophores have many clinica… 相似文献
999.
Fu Y.H. Smeets R.P.P. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1989,17(5):727-729
The authors present the results of DC vacuum arc lifetime and voltage measurements for contacts with different surface microstructures. This was realized by treating the contact surface with emery paper of varying roughness. The contact surface microstructure was found to have a large effect on the DC arc lifetime (several tens of times difference at the most) and arc voltage (30% difference at the most). The mechanism of the surface microstructure effect on DC arc stability was analyzed and is explained preliminarily. The rougher the contact surface is, the longer the arc lifetime and the more stable. The arc itself has a tendency to condition the surface in a way that is unfavorable for a sustained arc lifetime. The crater size for a rough surface is smaller than for a smooth one. The rougher the contact is, the lower the arc voltage (both DC and HF components). The arc erosion has a tendency to increase the arc voltage. It is probable that type I cathode spots (fast motion, small crater size) correspond not only to the surface contamination, but also to the surface roughness 相似文献
1000.