关于均匀总体样本的几个性质

应用推导随机(向量)函数分布的有关知识，给出了均匀总体样本的中位数、样本极差及样本分量乘积的负对数的概率分布。     

国产300MW汽轮机汽封改造

本文简要地分析了汽封弧段卡涩的问题,介绍了某厂300MW汽轮机组汽封改造的几点措施,从一个侧面对提高老机组的可靠性和经济性作了有益的探索。     

Stochastic optimal control of first-passage failure for rectangular thin plate vibration model under gaussian white-noise excitations

A rectangular thin plate vibration model subjected to inplane stochastic excitation is simplified to a quasinonintegrable Hamiltonian system with two degrees of freedom. Subsequently a one-dimensional Ito? stochastic differential equation for the system is obtained by applying the stochastic averaging method for quasi-nonintegrable Hamiltonian systems. The conditional reliability function and conditional probability density are both gained by solving the backward Kolmogorov equation numerically. Finally, a stochastic optimal control model is proposed and solved. The numerical results show the effectiveness of this method.     

新FRP技术加固钢筋混凝土矩形柱改善延性的试验研究

Reinforced concrete （RC） columns lacking adequately detailed transverse reinforcement do not possess the necessary ductility to dissipate seismic energy during a major earthquake without severe strength degradation. In this paper, a new retrofit method, which utilized fiber-reinforced plastics （FRP） confinement mechanism and anchorage of embedded bars, was developed aiming to retrofit non-ductile large RC rectangular columns to prevent the damage of the plastic hinges. Carbon FRP （CFRP） sheets and glass FRP （GFRP） bars were used in this test, and five scaled RC columns were tested to examine the function of this new method for improving the ductility of columns. Responses of columns were examined before and after being retrofitted. Test results indicate that this new composite method can be very effective to improve the anti-seismic behavior of non-ductile RC columns compared with normal CFRP sheets retrofitted column.     

矩形截面纤维流场压降及细颗粒扩散捕集效率

采用格子波尔兹曼气固两相流模型模拟扩散机制下矩形纤维捕集颗粒过程,研究纤维周围流场压降和扩散捕集效率随不同纤维布置方式的变化规律。把模拟得到的值（系统压降与捕集效率）与相同体积分数的圆柱纤维所对应的理论值相比,得到相应比例系数。分析规律,并采用Levenberg-Marquardt方法对其进行处理,得到相应比例系数的拟合公式。根据已有的圆形纤维压降与扩散效率的理论公式,再结合求得的拟合公式,对不同工况下的矩形纤维系统压降和扩散捕集效率进行计算。分析结果发现：矩形纤维系统压降与放置角度和长宽比均相关;而扩散捕集效率与长宽比成正比,与放置角度基本无关。     

矩形管柱和H形钢梁端板连接分析

高频焊接矩形管生产效率高,抗扭性能好,平面外刚度大,根据需要内部可充填混凝土以提高抵抗局部屈曲的能力,比焊接H型钢的轻钢厂房有更好的经济性。为提高梁柱连接节点的承载力、减小节点变形,需在节点区外包槽钢。本文分析了节点区不同厚度、不同形式外包槽钢和不同的柱内加劲肋设置等对节点强度和刚度的影响,得出了满足刚性连接要求的节点区外包槽钢厚度计算公式。研究了柱加劲肋、螺栓排列、螺栓数目、槽钢宽度和槽钢下伸长度等的影响。建议了箱形柱柱顶与梁上翼缘齐平,槽钢与梁端板等厚,槽钢向上伸出长度以满足安装一排高强螺栓的要求,并设置三角形加劲肋与柱顶盖板和槽钢焊接,箱形柱顶和槽钢内面满焊的节点形式。分析表明这种节点有很高的刚度和强度,能满足刚性连接的要求。     

E-characteristic polynomials of real rectangular tensor

By the resultant theory, the E-characteristic polynomial of a real rectangular tensor is defined. It is proved that an E-singular value of a real rectangular tensor is always a root of the E-characteristic polynomial. The definition of the regularity of square tensors is generalized to the rectangular tensors, and in the regular case, a root of the E-characteristic polynomial of a special rectangular tensor is an E-singular value of the rectangular tensor. Moreover, the best rank-one approximation of a real partially symmetric rectangular tensor is investigated.     

探索商品包装问题与绿色包装的发展之路

随着经济的发展,包装也越来越被人们重视,成为构成商品不可缺少的一部分。然而,目前市场上流行的包装方式和包装材料,往往造成资源的大量浪费和环境的严重污染。从现代包装中存在的虚空包装、多层过度包装等问题出发,提出绿色包装的概念,阐述了发展绿色包装应从绿色包装材料、包装设计以及政策法规入手,同时应加大环境标志制度的推广,从而实现绿色包装的目的。     

确定空中弧型标志提高铅球运动员最后用力效应的训练

以运动生物力学基础理论为依据，探讨确定空中定点孤型标志的方法，以体现一定投掷距离其各项因素的最优组合。通过拟定数学理论模型确定控制目标值，并应用于实践训练，增强运动员主体意识，使运动技能与运动素质迅速而有效地合成，获得理想的运动成绩。     

钢铁发蓝工艺研究

对几种常见的钢铁发蓝工艺的原理、流程、应用效果、研究现状及发展趋势进行了简要评述,介绍了几种常见发蓝工艺的原理、应用效果和研究现状,指出经济节能,高效稳定,安全环保的发蓝新工艺是未来的发展趋势。