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61.
The cavity induced by top-blow gas jets impinging on the bath surface is one of most important parameters, which has overwhelming influence on the rate of slag formation and metallurgical performance. Water model experiments are conducted through a 1/10 scaled-down top-blown convertor. Effects of lance height and gas flow rate on penetration behavior are studied, and also the influence mechanism of liquid surface tension on penetration depth is addressed based on the experiments and theory analysis. An energy utilization index (EUI) is defined to reflect how much the impinging kinetic energy of gas jets are transferred into bath for formation of cavity, and an improved model is proposed to predict penetration depth of jets. The results show that penetration depth increases with lowering lance height and increasing gas flow rate, and impact diameter increases with increasing lance height, but is little affected by gas flow rate. Influence of liquid surface tension on penetration depth is enhanced with increasing surface tension and penetration depth. The EUI increases with increasing lance height, and a function relationship of it with lance height is obtained based on the experiments. 相似文献
62.
Some new concepts of coneD_s convexity,coneD-s quasiconvexity,cone D-s pseudoconvexity,s right derivative of vector value mapping are proposed;and their related properties are discussed;the optimality necessary conditions and sufficient conditions for constrained extremum problem(VP)involving in cone D-s convex mapping are extablished;the relation between local optimal solution and global optimal solution;as well as the relation between weakly efficient solution and efficient solution for (VP) are derived;the corresponding results generalize the related results of classic convex programming. 相似文献
63.
XU Jiang WANG Wei-zhong YANG Xiu-gui WANG Hongl Disaster Control Engineering Under the State Ministry of Education Chongqing University Chongqing Chin 《保鲜与加工》2004,(12):60-62
The deformation characteristics of the fine-sandstone is studied under the loading and unloading conditions at the three different deformation-rates and the two different stress-levels. The experimental results show that there is really the plastic-loop in the deformation curve for the loading deformation curve is different from the unloading deformation curve. But the plastic-loop is nearly unchangeable since the second circulate loading. The residual-deformation is be almost zero since the second circulate loading, and that the slope of the deformation curve increases as the deformation-rate increases, and that the residual-deformation increases as the stress-levels increases. 相似文献
64.
The feasible control problem is presented for the day-operation of the Three-Gorge Caseade Hydropower Station. The significance of the problem is explained. Basic propetties ofthe problem and the approaches to study it are discussed. Two methfods are given for solving theproblem. which are calculus of variation and linear programming. In the former. the Euler equationwith time-lag and the generalised two-point boundary conditions are obtained and the correspondingpractical implication is interpreted. In the latter. the rationality for the discrete model is exptainedand the computalional details are given for the implement software. some questions which should bepaid much attentfon and the corresponding propeels are prasented based on the numerical results andtheoretical analysis 相似文献
65.
The deformation characteristics and the plastic-loop of the fine-sandstone is studied under the loading and(unloading) condition at the three different deformation-rates and the two different stress-levels,the results show: 1) There is really the plastic-loop in the deformation curve for the loading deformation curve is different form the unloading deformation curve.But the plastic-loop is nearly unchangeable since the second circulate loading.2) There is different for every imitational parameter between the first deformation curve and the second deformation curve at the different stress-levels and the different deformation-rates,but every imitational parameters become more and more invariable gradually since the second circulate curve.3) With the change of the deformation-rates and stress-levels,the imitational(parameters) will change with it.4) The imitational parameters are different for loading section and unloading section of the fine-sandstone deformation curve at the same circulate curve under the same deformation-rate and stress-level. 相似文献
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预算实际上是一种建模,即根据过去和现在已有的信息建立一个从过去引伸到未来的模型。而时序分析法和灰色系统理论是两种有效的预测方法。为此,介绍了这两种预测方法的原理,并预测了新疆兵团的农机情况。其结果表明:未来10年,新疆农机总动力和投入将会有较大幅度的增长,而农业机械化程度将趋于最高值。 相似文献
70.
污泥中富含N,P,K及有机质,是天然的有机肥料。因此,污泥的农用是污泥处置的最佳途径。污泥农用的主要途径有农田施用、林地施用、研制复合肥以及作为土壤改良剂。为此,结合实例阐述了我国污泥农用资源化处置现状及未来发展趋势,并指出了污泥农用的发展方向。 相似文献