Multi-objective aerodynamic optimization design of high-speed train head shape     

Liang Zhang  Ji-ye Zhang  Tian Li  Ya-dong Zhang 《浙江大学学报(A卷英文版)》2017,18(11):841-854

To improve the aerodynamic performance of high-speed trains (HSTs) running in the open air, a multi-objective aerodynamic optimization design method for the head shape of a HST is proposed in this paper. A parametric model of the HST was established and seven design variables of the head shape were extracted. Sample points and their exact values of optimization objectives were obtained by an optimal Latin hypercube sampling (opt. LHS) plan and computational fluid dynamic (CFD) simulations, respectively. A Kriging surrogate model was constructed based on the sample points and their optimization objectives. Taking the total aerodynamic drag force and the aerodynamic lift force of the tail coach as the optimization objectives, the multi-objective aerodynamic optimization design was performed based on a non-dominated sorting genetic algorithm-II (NSGA-II) and the Kriging model. After optimization, a series of Pareto-optimal head shapes were obtained. An optimal head shape was selected from the Pareto-optimal head shapes, and the aerodynamic performance of the HST with the optimal head shape was compared with that of the original train in conditions with and without crosswinds. Compared with the original train, the total aerodynamic drag force is reduced by 2.61% and the lift force of the tail coach is reduced by 9.90% in conditions without crosswind. Moreover, the optimal train benefits from lower fluctuations in aerodynamic loads in crosswind conditions.  相似文献   

“标准米”之谜的澄清与解决——从“逻辑行动主义方法论”的视角看     

冯立荣  王丽 《毕节学院学报》2016,(6):47-52

“逻辑行动主义方法论”的要旨在于严格界划由言语行动之产品构成的“语言域”、由心智行动之产品构成的“思想域”以及由客观行动的对象构成的“对象域”.“标准米”是当今学界最受争议的先验-偶然知识谜题.使用逻辑行动主义方法论可以澄清相关研究中存在的诸多混乱,揭示出标准米示例不具备先验-偶然知识资质的真正原因,同时也可以为进一步说明先验-偶然知识论题的合理性奠定基础.  相似文献   

Symmetric alteration of four knots of B-spline and NURBS surfaces     

LI Ya-juan WANG Guo-zhao 《浙江大学学报(A卷英文版)》2006,7(6):1084-1087

INTRODUCTION Modification of knots of a B-spline curve changes the shape of the curve. In some recent pub-lications (Juhász and Hoffmann, 2001; 2003; Hoff-mann and Juhász, 2004; Li and Wang, 2005), the authors studied the effect of the alteration of a single knot on the shape of the curve. Hoffmann (2004) and Li & Wang (2006) applied these theories into the constrained shape modification of B-spline and NURBS curves. Juhász (2001) and Hoffmann & Ju-hász (2005) studied the effe…  相似文献   

我国高等继续教育持续发展方略   总被引：5，自引：0，他引：5  

李平  郭慧珍 《中国高教研究》2007,(4):38-41

近年来,我国高等继续教育在高等教育大众化发展历程中发挥着重要作用,同时自身也取得了长足的发展,并形成目前的基本格局。随着高等教育向内涵发展方向的调整,高等继续教育要想保持发展态势,必须在坚持特色、充实内涵、提高实力上下功夫。  相似文献   

行政公开的再思考     

牛丽云 《青海师专学报》2003,23(3):73-75

提起行政公开，作为占有社会整体信息总量90％以上的政府自然是首当其冲的，尤其是在我们这样一个社会主义国家里。众所周知，社会主义民主的本质就是人民当家作主。政府是人民的公仆，公仆办事情，主人应当知道，否则人民怎样当家作主?人民当家作主要靠参政议政才能实现，而参政议政权实现前提就是政府行为的公开。因而确立行政公开原则，不仅能使行政权得到有效的控制和监督，而且能使公民的民主政治意识大大增强，只有这样，才能实现我国法治现代化的目标。笔者想通过这篇文章再次探讨行政公开的涵义、行政公开的法律意义以及行政公开在我国发展和完善的途径。  相似文献   

冻融、温度等理化因素对卵黄抗体AGP效价的影响     

王成明  李运敏  柳卫国 《安徽科技学院学报》1995,(4)

按常规方法制备抗鸡传染性法氏囊炎卵黄抗体（ｙｏｌｋａｎｔｉｂｏｄｙ，ＹＡ），经冻融、温度、机械振荡、光照和防后剂（０．０１％流柳汞、０．０１％叠氮钠和０．５％苯酚）等处理后测定其琼脂扩散试验（Ａｇａｒｇｅｌｎｒｅｄｒｉｔａｔｉｏｎ，ＡＧＰ）效价的变化．实验结果表明，冻融毛次后卵黄抗体的ＡＧＰ效价自１：６４降至１：３２，冻融６次降至１：１６，０．５％苯酚的存在使ＹＡ的ＡＧＰ效价自１：６４降至１：１６；其它物理因素对ＹＡ的ＡＧＰ效价影响不明显．  相似文献   

思想道德修养课教育艺术探讨     

李健敏 《梧州学院学报》2001,11(1):1-5

本文通过阐述思想品德形成、发展的规律,探讨思想道德修养课的教育艺术.  相似文献   

A four spiral slots microstrip patch antenna for radiotelemetry capsules based on FDTD     

HUANG Biao YAN Guo-zheng LI Qian-ru 《浙江大学学报(A卷英文版)》2007,8(10):1560-1567

Antenna is very crucial to radiotelemetry capsules which can measure the physiological parameters of the gastroin- testinal (GI) tract. The objective of this paper is to design a novel spiral slots microstrip patch antenna for the radiotelemetry capsules communicating with external recorder at 915 MHz located in ISM (Industry, Science, and Medical) bands. The microstrip patch antenna is designed and evaluated using the finite-difference time-domain (FDTD) method. Return loss characteristics and the effect of the human body on resonant frequency are analyzed, and the performances of radiation patterns at different positions of the human alimentary tract are also estimated. Finally, specific absorption rate (SAR) computations are performed, and the peak 1-g and 10-g SAR values are calculated. According to the peak SAR values, the maximum delivered power for the designed antenna was found so that the SAR values of the antenna satisfy the ANSI (American National Standards Institute) limitations.  相似文献   

PLC在电梯中的应用     

李树元 《邢台职业技术学院学报》2002,19(3):65-68

本阐述了电梯在PLC控制下的硬件及软件的设计过程，列出了具体的主要硬件电路和电梯的控制形图，分析了主要输入点的作用，以及梯形图中主要继电器的作用。  相似文献   

基于混合遗传算法的模糊车间调度问题     

肖力 《鄂州大学学报》2006,13(6):17-19

该文介绍了模糊流水车间调度问题，在此基础之上设计了一个解决该问题的混合遗传算法——嵌入多点最速下降法的遗传算法（GDA），将其与各种算法进行了仿真比较，论证了其有效性。  相似文献