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针对航天型号多项目研发中面临的进度、质量问题,究其原因,多与资源协调与配置密切相关,文中结合项目计划中资源调度及优化问题,进行深入研究,给出此类项目及资源的模型描述,提出资源约束条件下基于遗传算法的多项目资源优化调度方法。实例显示,该方法能够帮助解决航天型号项目研发中多项目资源调度问题,有助于缓解因资源紧张或资源冲突带来的问题,进一步保障航天型号项目进度和质量。 相似文献
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为解决数据域直接定位(DPD)算法面临的计算压力,提高算法效率,提出一种基于修正的容积卡尔曼滤波(MCKF)的DPD算法。首先,融合各观测信号波达方向信息,利用子空间数据融合方法建立一种基于间接观测量的DPD滤波模型;然后,根据模型特点设计MCKF算法进行求解,解决间接观测量带来的噪声累积问题;最后,对算法计算量进行分析和对比,说明计算效率的提升。仿真结果表明,所提算法与基于最大似然遍历搜索和遗传算法的DPD算法相比,在相同的估计性能下,计算量下降明显,时效性显著提升,增加了算法实用价值。 相似文献
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Diamond-like carbon (DLC) films are deposited by the Hall ion source assisted by the mid-frequency unbalanced magnetron sput-tering technique. The effects of the substrate voltage bias, the substrate temperature, the Hall discharging current and the argon/nitrogen ratio on the DLC film’s performance were studied. The experimental results show that the film’s surface roughness, the hardness and the Young’s modulus increase firstly and then decrease with the bias voltage incrementally increases. Also when the substrate temperature rises, the surface roughness of the film varies slightly, but its hardness and Young’s modulus firstly increase followed by a sharp decrease when the temperature surpassing 120 ℃. With the Hall discharging current incrementally rising, the hardness and Young’s modulus of the film decrease and the surface roughness of the film on 316L stainless steel firstly decreased and then remains constant. 相似文献
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对于武装型直升机,在设计上通常都会兼顾考虑其隐身性,如选择雷达隐身、红外隐身、激光隐身、可见光隐身或集多种隐身功能于一身。为了验证直升机的隐身性能,就雷达隐身、红外隐身、激光隐身、可见光隐身在试验时所设置的飞行科目和方法作几点阐述,供飞行试验技术人员和飞行人员参考,为改进设计和使用提供依据。 相似文献
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Recently, halite and sulfate evaporate rocks have been discovered on Mars by the NASA rovers, Spirit and Opportunity. It is reasonable to propose that halophilic microorganisms could have potentially flourished in these settings. If so, biomolecules found in microorganisms adapted to high salinity and basic pH environments on Earth may be reliable biomarkers for detecting life on Mars. Therefore, we investigated the potential of Resonance Raman (RR) spectroscopy to detect biomarkers derived from microorganisms adapted to hypersaline environments. RR spectra were acquired using 488.0 and 514.5 nm excitation from a variety of halophilic archaea, including Halobacterium salinarum NRC-1, Halococcus morrhuae, and Natrinema pallidum. It was clearly demonstrated that RR spectra enhance the chromophore carotenoid molecules in the cell membrane with respect to the various protein and lipid cellular components. RR spectra acquired from all halophilic archaea investigated contained major features at approximately 1000, 1152, and 1505 cm(-1). The bands at 1505 cm(-1) and 1152 cm(-1) are due to in-phase C=C (nu(1) ) and C-C stretching ( nu(2) ) vibrations of the polyene chain in carotenoids. Additionally, in-plane rocking modes of CH(3) groups attached to the polyene chain coupled with C-C bonds occur in the 1000 cm(-1) region. We also investigated the RR spectral differences between bacterioruberin and bacteriorhodopsin as another potential biomarker for hypersaline environments. By comparison, the RR spectrum acquired from bacteriorhodopsin is much more complex and contains modes that can be divided into four groups: the C=C stretches (1600-1500 cm(-1)), the CCH in-plane rocks (1400-1250 cm(-1)), the C-C stretches (1250-1100 cm(-1)), and the hydrogen out-of-plane wags (1000-700 cm(-1)). RR spectroscopy was shown to be a useful tool for the analysis and remote in situ detection of carotenoids from halophilic archaea without the need for large sample sizes and complicated extractions, which are required by analytical techniques such as high performance liquid chromatography and mass spectrometry. 相似文献
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研究弹流润滑(EHL)转子-滚动轴承系统在碰摩-不对中耦合故障状态下的动力学响应.基于EHL理论与Hertz弹性接触理论,并考虑转静碰摩故障与转子不对中故障,建立耦合故障作用下转子-滚动轴承系统非线性动力学微分方程,通过龙格库塔数值解法进行求解得到故障状态下系统振动响应,对比分析其结果并在航空发动机转子实验台进行验证.研究结果表明:①考虑EHL理论对单一碰摩故障系统的影响较大.考虑EHL理论的系统进入拟周期运动与周期2运动状态时的转速较未考虑EHL理论系统明显提高,周期2解所处的转速区间较未考虑EHL理论系统大.②考虑EHL理论对碰摩-不对中耦合故障系统的影响较大.考虑EHL理论的系统由周期1解进入拟周期运动,且进入拟周期状态时的转速较未考虑EHL理论的系统明显提高.③通过计算结果与实验结果进行对比分析,可发现考虑EHL理论的耦合故障系统的转子在1/2倍频与2倍频处的振动响应均弱于未考虑EHL理论的系统,考虑EHL理论的模型比未考虑EHL理论的模型能更准确体现耦合故障系统的振动响应. 相似文献
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变量化约束草图驱动的药柱三维特征设计研究 总被引:1,自引:1,他引:1
为了直观而准确地支持固体火箭发动机药柱设计,提出了一种约束草图驱动的药柱三维特征造型方法。该设计方法首先通过变量化约束求解引擎对设计人员模糊的设计概念进行精确的几何坐标定位,形成一幅设计变量驱动的约束草图。然后,经过药柱特征定义,在设计规则和基于设计历史的燃面追溯统计算法的支持下,设计人员能够在约束草图上进行任意形式复杂药柱的特征定义、造型设计、燃面推移仿真与燃面统计。最后,开发了相应的药柱设计系统,并以一个管槽形药柱的设计过程,验证了本设计方法的计算效率、直观性、准确性和有效性。 相似文献