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41.
Sun Shufen 《Acta Mechanica Sinica》1987,3(1):44-51
The coupled model has been developed in this study for moisture transport and beat exchange in soil. The model is driven by
atmospheric conditions measured in a field. The concept that soil has a surface resistance to evaporation is introduced in
order to relate the evaporation from surface with the vapour flux in air. With the use of this concept, the simulation results
agree quite well with the measured data. 相似文献
42.
ABSTRACT. An indicator defined as a function of the total water diversion through the Coleambally canal and the potential irrigation demand is selected to represent the sustainability of the irrigation water system in the Coleambally irrigation area, Australia. A simulation procedure using a system dynamics approach was developed to evaluate the indicator. The procedure includes water diversion assessment, potential crop water demand and total gross margin. Three cases of water supply options (surface water, ground water pumping and water trading), two cases of changes in the total agricultural area and three cropping pattern scenarios were simulated to better understand their impact on sustainability. The simulated results indicate that increasing the agricultural area reduces the sustainability of the irrigation system because the demand of water increased despite increase in the gross margin. The scenarios show that imposed water trading and ground water pumping would considerably increase the supply system having a positive impact on the sustainability. The paper concludes that a multi‐objective sustainability indicator taking account of economic and environmental issues could be more useful. 相似文献
43.
高分子阳离子絮凝剂用于炼油废水处理研究 总被引:15,自引:0,他引:15
用聚二甲基二烯丙基氯化铵型高分子阳离子絮凝剂处理炼油废水考察了险油和化学耗氧量的动态变化规律。对产生的浮渣性质及滤饼的成份进行了研究。并且与聚合铝的处理效果进行对照。研究结果表明,HCA除油和化学耗管氧量的性能优于PAC,HCA产生的浮渣是PAC的三分之一,而浮渣中的含油量则是PAC的三倍。 相似文献
44.
Noncooperative games are used to demonstrate that, while free riding is always an option, the “tragedy of the commons” is not inevitable. When the decision to cooperate or free ride is considered in a dynamic setting, there is no intermediate case where some cooperate and others free ride. The game is only stabilized in either full cooperation or full defection. The important factor in obtaining a cooperative outcome is the critical number of players that decide to cooperate. The concept of commitment is used to demonstrate the necessary and sufficient conditions for full cooperation. Although the analysis is based on a shared water resource, it can be extended to other natural resources with common costs and private benefits, especially in the cases where there are no international authorities or treaties that internalize the externalities involved in privatizing the resource. 相似文献
45.
P. A. V. Ferreira M. E. S. Machado 《Journal of Optimization Theory and Applications》1996,89(3):659-680
Projection and relaxation techniques are employed to decompose a multiobjective problem into a two-level structure. The basic manipulation consists in projecting the decision variables onto the space of the implicit tradeoffs, allowing the definition of a relaxed multiobjective master problem directly in the objective space. An additional subproblem tests the feasibility of the solution encountered by the relaxed problem. Some properties of the relaxed problem (linearity, small number of variables, etc.) render its solution efficient by a number of methods. Representatives of two different classes of multiobjective methods [the Geoffrion, Dyer, Feinberg (GDF) method and the fuzzy method of Baptistella and Ollero] are implemented and applied within this context to a water resources allocation problem. The results attest the computational viability of the overall procedure and its usefulness for the solution of multiobjective problems.This work was partially sponsored by grants from CNPq and FAPESP, Brazil. The authors are indebted to the anonymous reviewers for their valuable comments. 相似文献
46.
Likelihood estimation of soft-core interaction potentials for Gibbsian point patterns 总被引:3,自引:3,他引:0
Yosihiko Ogata Masaharu Tanemura 《Annals of the Institute of Statistical Mathematics》1989,41(3):583-600
The likelihood method is developed for the analysis of socalled regular point patterns. Approximating the normalizing factor of Gibbs canonical distribution, we simultaneously estimate two parameters, one for the scale and the other which measures the softness (or hardness), of repulsive interactions between points. The approximations are useful up to a considerably high density. Some real data are analyzed to illustrate the utility of the parameters for characterizing the regular point pattern. 相似文献
47.
We formulate the super-KMS condition suggested by Connes and Kastler, in the context of entire cyclic cohomology of quantum algebras. We show that the Chern character of Jaffe, Lesniewski, and Osterwalder — associated by Kastler to a super-KMS functional — satisfies the entire growth condition. Hence, a super-KMS functional defines a cocycle for the entire cyclic cohomology of quantum algebras.Supported in part by the National Science Foundation. 相似文献
48.
Yuichiro Tada Masakatsu Ueno Noriaki Tsuchihashi Kiyoshi Shimizu 《Journal of solution chemistry》1992,21(9):971-985
The limiting molar conductances ° of deuterium chloride DCl in D2O were determined as a function of pressure and temperature in order to examine the proton-jump mechanism in detail. The excess deuteron conductances °E(D
+), as estimated by the equation [°E(D
+) = °(DCl/D
2
O) – °(KCl/D
2
O)], increases with an increase in the pressure and temperature as well as the excess proton conductance [°E(H
+) = °(HCl/H
2
O) – °(KCl/H
2
O)]. The isotope effect on the excess conductances, however, depends on the pressure and temperature contrary to the model proposed by Conway et al.: °E(H
+)/°E(D
+) decreases with increasing pressure and temperature. The magnitude of the decrease with pressure becomes more prominent at lower temperature. These results are discussed in terms of the pre-rotation of adjacent water molecules, the bending of hydrogen bonds with pressure, and the difference in strength of hydrogen bonds between D2O and H2O. 相似文献
49.
合成丙交酯中微量水分分析 总被引:3,自引:0,他引:3
合成丙交酯中微量水分分析徐溢,柳胜春(重庆大学化工学院分析教研室630044)关键词丙交酯,微量水,定量分析丙交酯是人工合成骨材料聚乳酸的合成中间体,其性能决定着合成产品的品质,要获得高质量的合成材料,对中间体的分析和监测十分重要。一般要求丙交酯中间... 相似文献
50.
T. Katsuki 《Russian Chemical Bulletin》2004,53(9):1859-1870
The recent development of asymmetric Baeyer—Villiger oxidation of prochiral and racemic ketones is briefly summarized, focusing on the regio- and stereocontrol of the oxidation attained by regulating the stereoelectronic demand in the step of rearrangement of the Criegee intermediate.Based on the report presented at the International Conference Modern Trends in Organoelement and Polymer Chemistry dedicated to the 50th anniversary of the A. N. Nesmeyanov Institute of Organoelement Compounds of the Russian Academy of Sciences (Moscow, May 30–June 4, 2004).Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1784–1794, September, 2004. 相似文献