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121.
对最优化算法的统一研究已有不少方法,诸如无约束最优化问题中的Broyden和Huang算法类,带线性约束的非线性规划问题中越民义等人引进的可行方向算法类。对非线性规划的退化问题理论上也有一些处理方法。例如,在迭代的每一次开始都求解一个线性 相似文献
122.
地震作用下多层钢结构的抗力退化与倒塌预测 总被引:1,自引:0,他引:1
陈以一 《同济大学学报(自然科学版)》1996,24(2):130-135
分析房屋结构的倒塌过程,使在某种程度上能预测强震作用下房屋的破坏状况,使所设计的房屋能满足“大震不倒”,故意义重大,判断结构倒塌危险程度,可以用抗力退化率作为指标,对于弹塑性地震反应,提出“机构坐标系”的概念,为不同破坏模式的框架结构提供一个统一的、易于判读抗力退化率的方法,数值分析和荷载试验的结果分析表明,对低层和多层钢框架来说,根据等效静力荷载作用下的弹塑性分析结果,可以简略地推断在水平地震作 相似文献
123.
对任意简单图G,△(G)和XT(G)分别表示G的最大度和全色数。证明了当△(G)≥4时,2-退化图G的全色数XT(G)=△(G)+1。 相似文献
124.
依照重力式挡土墙双重控制设计法的设计原理,使抗滑安全系数为给定值,以此计算抗滑所需之总重力,根据地基承载力设计值计算基础底面面积,根据恒定的断面面积,计算墙面坡度。按本文设计挡土墙,方法简便、迅速,计算结果安全、经济。 相似文献
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126.
在日本商务界,人们尽管公务繁忙,使用的语言却十分讲究和规范。既不失礼仪又简洁明了,以便提高工作效率。所以,一个训练有素的业务人员应懂得电话传达法、电话呼叫方法、寒暄语的正确使用及同事之间、上下级之间的称呼方式和数据中数字的读出。 相似文献
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128.
Great efforts have been made to resolve the serious environmental pollution and inevitable declining of energy resources. A review of Chinese fuel reserves and engine technology showed that compressed natural gas (CNG)/diesel dual fuel engine (DFE) was one of the best solutions for the above problems at present. In order to study and improve the emission performance of CNG/diesel DFE, an emission model for DFE based on radial basis function (RBF) neural network was developed which was a black-box input-output training data model not require priori knowledge. The RBF centers and the connected weights could be selected automatically according to the distribution of the training data in input-output space and the given approximating error. Studies showed that the predicted results accorded well with the experimental data over a large range of operating conditions from low load to high load. The developed emissions model based on the RBF neural network could be used to successfully predict and optimize the emissions performance of DFE. And the effect of the DFE main performance parameters, such as rotation speed, load, pilot quantity and injection timing, were also predicted by means of this model. In resum6, an emission prediction model for CNG/diesel DFE based on RBF neural network was built for analyzing the effect of the main performance parameters on the CO, NOx emissions of DFE. The predicted results agreed quite well with the traditional emissions model, which indicated that the model had certain application value, although it still has some limitations, because of its high dependence on the quantity of the experimental sample data. 相似文献
129.
Land degradation is one of the severe environmental problems in China. In order to combat land degradation, a soil conservation program was introduced since 2000 to reduce soil erosion by converting slope-cultivated land into forestry and pasture. This paper represents the first systematic attempt to investigate the impact of the soil conservation program on land degradation in the loess plateau. The results indicate that the soil conservation program to convert slope fields into forest or pasture is an effective way to combat soil erosion. However, a subsidy that is higher than profit of land use activity of slope fields before their conversion into forest and pasture is needed to encourage farmers to join the conservation program. A policy measure to encourage and assist farmers to develop sedentary livestock by using crops produced from fields as well as fodder and forage grass from the converted slope fields might contribute to combat soil erosion. Increase in off-farm job opportunities may encourage households to reduce cultivation in slope fields. That implies a policy measure to encourage rural urbanization might contribute to combat soil erosion. 相似文献
130.
合成了一个新的化合物,4-(N,N-二乙酰氧乙基氨基)苯甲醛缩肼基硫代酸苄酯,运用FT-IR,1H-NMR,UV-Vis,元素分析等进行了表征分析,测定了该化合物的荧光性质,从理论上分析了该化合物"反常"的双重荧光现象。 相似文献