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复合材料螺旋桨结构高效优化方法研究 总被引:1,自引:0,他引:1
提出了一种能求解整数规划问题的改进遗传算法,并将其用于复合材料螺旋桨结构优化问题。首先,提出一种新颖的优化模型建模方法,该方法在不影响优化结果的同时,能大幅减少设计变量个数,从而缩小优化空间,有效的提高优化效率。然后从整数编码、锦标赛选择以及加速策略等方面对遗传算法进行改进,使之成为一种能同时优化铺层层数和铺层顺序的高效算法。笔者所提的优化方法被用来求解该复合材料螺旋桨优化问题,优化时间缩短6倍,重量减少32%,固有频率提高30%,获得了较好的优化结果。 相似文献
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用传递函数估计小阻尼的新方法 总被引:2,自引:0,他引:2
提出一种对冲激响应函数信号采一段连续样本 ,对样本从起始点和隔 L点为新起始点分别进行两次同样点数的傅立叶变换 ,再分别与输入的力信号进行两次传递函数分析 ,利用其对应谱峰处的幅值计算出阻尼的方法。不考虑模态耦合 ,这是一种精确估计小阻尼的方法 ,不受时域截断产生的能量泄漏的影响 ,能应用于多自由度系统阻尼的求解。仿真结果表明 :阻尼识别精度高 ,当无噪声干扰时 ,最大误差只有 1.6 3% ;有噪声时 ,选取合适的采样频率和延迟点数 ,阻尼的最大误差也只有 1.33%。在两个频率成分靠得很近和大阻尼情况下 ,不能使用这种方法 相似文献
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用于高精度小尺寸零件制作的光固化快速成型技术的现状与发展 总被引:4,自引:0,他引:4
用于高精度小尺寸零件制作的光固化快速成型技术源于快速原型技术 ,利用光诱导树脂固化 ,实现逐层堆积的原理制作零件原型。本文回顾了近年来该领域中开发出的主要工艺方法、原理及系统构成 ;本文还提出了以变形反射镜器件为核心构建新型动态视图发生器 ,采用整层曝光固化工艺实现原型快速制作的新方法。和其它方法使用的动态视图发生器相比 ,本文提出的新型动态视图发生器具有更高的分辨率和更高的对比度 (可达 10 0 0∶1)。 相似文献
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《仪器科学与技术》2013,41(4):461-471
Abstract The measurements of the K x‐ray intensity ratio I(Kβ)/I(Kα) for the 16 elements, Ag, Cd, Sn, Sb, Cs, Ba, La, Ce, Pr, Sm, Eu, Gd, Tb, Dy, Ho, and Er, have been done following ionization by 59.5 keV γ‐rays from a 241Am point source. Ratios of emission probabilities Auger electrons and the vacancy transfer coefficients have been extracted in terms of the intensity ratios. The obtained results agree with previously published experimental results. 相似文献
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在机加工车间,钳工师傅去除铣削或钻削工件的毛刺,通常采用锉刀修锉的方法。该方法对于尺寸较大工件来说,从工件装夹到整个工序的完成均比较奏效,然而对于尺寸较小的工件(如外形尺寸为:10mm×10mm×10mm),装夹和修锉都比较困难,且劳动效率相当低。本文介绍一种针对小工件去毛刺的新方法:用一个一端封闭、一端带有螺钉可拆卸端盖的筒体(筒体的外形尺寸视工件的数量自定)盛装约1/3体积砂子,再把需要去毛刺的工件装入筒体(工件总体积约占筒体体积的1/3),装上可拆卸端盖,然后将筒体反复摇几次,使得砂子和工件搅拌均匀。这时将装有砂子和工件的筒… 相似文献
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E. M. Dianov E. B. Intyushin V. V. Koltashev V. G. Plotnichenko Yu. I. Chigirinskii 《Instruments and Experimental Techniques》2004,47(5):662-664
A simple method for measuring Raman light scattering by thin films is proposed. It allows the negative effect of the substrate material onto which various coatings are deposited to be excluded. Raman scattering spectra are presented. 相似文献
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A detector of 3.02-MeV protons and 2.45-MeV neutrons is designed for experiments with the injection of deuterium atomic beams in a Gas-Dynamic Trap facility. An organic scintillator and a phototube with a fine-mesh dynode system are used in the sensor. The detector is operated in the mode of single-particle counting; the time resolution is 20 ns. Discrimination between different particles is effected by using a controlled damper that shuts off the proton flow and also by analyzing pulse-height spectra. The sensor is inserted in a vacuum chamber; the rotating mechanism of the sensor and location of the ports in the facility enables measurements along the plasma column. 相似文献
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小工件平行度垂直度测量新方法及精度分析 总被引:3,自引:0,他引:3
介绍了一种检测小工件平行度和垂直度的新方法。利用反射棱镜将常规的问接测量变为直接测量,使测量不受外部环境的影响,方便、快速、准确,文章还对测量误差作了分折,并提出了消除误差的方法。 相似文献
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In order to coordinate the contradiction between the dynamic performance and the economic performance of PEVs, this paper proposed a comprehensive shift schedule based on a two-speed PEV powertrain. Firstly, the strategies of obtaining the torque for low energy consumption were presented under the economic performance mode. Then the dynamic shift schedule and the economy shift schedule for a two-speed powertrain were formulated. The optimization model of comprehensive shift schedule was established with the objectives of the acceleration time during 0~100 km/h and the energy consumption per unit mass. And then the model was solved by the crossover particle swarm optimization algorithm to obtain the shift schedule curves. Three kinds of shift schedule were compared and analysed by using MATLAB/Simulink platform. Results show that the comprehensive shift schedule for low energy consumption may balance the dynamic performance and the economic performance of PEVs. 相似文献
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M. M. Matlin A. I. Mozgunova E. N. Kazankina V. A. Kazankin 《Journal of Friction and Wear》2018,39(3):195-199
A unified analytical dependence for determining the full convergence at the contact between the sphere and flat surface of has been obtained and experimentally confirmed. It is valid both under the conditions of purely elastic deformation and elastoplastic deformation. 相似文献
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V. A. Khryachkov I. V. Dunaeva M. V. Dunaev N. N. Semenova 《Instruments and Experimental Techniques》2003,46(1):19-25
A method for measuring the specific energy losses of fission fragments is described. It is based on the digital processing of signals from a double Frisch-grid ionization chamber. The energy losses of 252Cf fission fragments were measured for masses and energies varying over wide ranges. A method is proposed for a more correct account of fission-fragment energy losses in the targets and entrance windows of spectrometers. 相似文献
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讨论了数字图像处理中跟踪移动目标的相关算法,提出了低信噪比情况下小目标检测的解决方案,提出了目标跟踪稳定性和准确性。 相似文献