摘要：介绍了一种基于DSP视频采集系统进行设计的新方法。采用TI公司低端DSP芯片TMS320F2812(2812)实现了对CCD输出的标准视频信号的实时采集处理,通过帧积分的实时处理方法提高了采集图像的信噪比,系统具有结构简单、可靠性高、使用灵活和性价比高等优点。详细地描述了硬件设计、软件流程和2812全速AD转换的实现方法。

摘要：研究了具有模型参数不确定和受空间环境干扰影响的挠性航天器姿态大角度快速机动快速稳定控制问题,设计了一种受细胞膜放电模型启发的鲁棒姿态控制器。综合考虑挠性航天器的强非线性和强耦合特性,设计了对模型参数和环境干扰具有鲁棒性的姿态机动控制器。为了减小机动中姿态突变激发的挠性附件振动,基于细胞膜放电的动力学模型设计了一种改进的鲁棒控制器。当参数不确定范围和干扰有界时,所提鲁棒控制器可使闭环系统的解最终一致有界。最后,分析了控制器参数对姿态控制性能及所需能量的影响。数值仿真验证了所提鲁棒控制器用于姿态机动控制可以得到良好的效果。

摘要：重点研究基于相似方法的菱形传动斯特林发动机各关键参数设计以及实验台架搭建,并通过电加热系统模拟外部热源进行热力性能测试。实验过程中记录斯特林发动机的运行温度、充气压力、转速以及输出轴功率等性能参数。根据实验结果对影响斯特林发动机输出特性的参数进行分析,得到实验样机在工作温度为600℃,充气压力1.5 MPa时的最佳输出功率为289 W。

摘要：针对鲸鱼优化算法(WOA)后期全局搜索能力不足等问题,提出一种基于自适应惯性权重和差分进化的改进鲸鱼优化算法(IWOA),并针对工程结构存在的外部载荷、材料强度等不确定性因素,将结构的系统可靠性引入优化设计中作为约束条件,对结构进行最小化重量优化。通过构建相关优化模型,对算例进行优化计算。结果表明:改进鲸鱼优化算法在基于可靠性的优化设计中,具有较快的收敛速度和较好的求解精度及稳定性,是一种有效的优化设计方法。

摘要：根据导向叶片的曲面结构,运用SST湍流模型,对涡轮叶栅通道内部的三维流场和圆形气膜孔叶片型面的冷却效果进行了数值模拟,在设计工况下,分析气膜孔倾角的改变对吸力面冷却效果的影响.研究结果为:无论改变哪排气膜孔的倾角,前倾的冷却效果总是高于后倾;相比之下,第一排气膜孔的倾角发生变化后对冷却效果的影响最大.

摘要：The purpose of this study was to establish a method for measuring the knee valgus angle from the ana- tomical and mechanical axes on three-dimensional reconstruction imaging models, and to use this method for estimating an average knee valgus angle value for northern Chinese adults. Computed tomographic angiography data in DICOM format for 128 normal femurs from 64 adult subjects were chosen for analysis. After the femur images were subjected to three-dimensional reconstruction, the deepest point in the intercondylar notch （point A）, the midpoint of the medullary cavity 20 cm above the knee-joint line （point B）, and the landmark of the femoral head rotation center （point C） were identified on each three-dimensional model. The knee valgus angle was defined as the angle enclosed by the distal femoral anatomical axis （line AB） and the femoral mechanical axis （line AC）. The average （mean＋SD） of knee valgus angle for the 128 femurs was 6.20°±1.20° （range, 3.05° to 10.64°）. Significant positive correlations were found between the knee valgus angles of the right and left sides and between the knee valgus angle and age. During total knee arthroplasty, choosing a valgus cut angle of approximately 6° may achieve a good result in reestablishing the natural mechanical alignment of the lower extremity for patients of northern Chinese ethnicity. Larger valgus cut angles should be chosen for older patients.

摘要：The objective of this study was to investigate the mechanical characteristics of implant-abutment interface design in a dental implant system, using nonlinear finite element analysis （FEA） method. This finite element simulation study was applied on three commonly used commercial dental implant systems： model I, the reduced-diameter 3i implant system （West Palm Beach, FL, USA） with a hex and a 12-point double internal hexagonal connection; model II, the Semados implant system （Bego, Bremen, Germany） with combination of a conical （45° taper） and internal hexagonal connection; and model III, the Br,~nemark implant system （Nobel Biocare, Gothenburg, Sweden） with external hexagonal connection. In simulation, a force of 170 N with 45°oblique to the longitudinal axis of the implant was loaded to the top surface of the abutment. It has been found from the strength and stiffness analysis that the 3i implant system has the lowest maximum yon Mises stress, prirlcipal stress and displacement, while the Br^nemark implant system has the highest. It was concluded from our preliminary study using nonlinear FEA that the reduced-diameter 3i implant system with a hex and a 12-point double internal hexagonal connection had a better stress distribution, and produced a smaller displacement than the other two implant systems.

摘要：全固态锂电池因其优异的安全性和高能量密度成为储能领域的重点研究内容。硫化物电解质因其高离子电导率、良好电极/电解质界面兼容性及易加工性,有力推动了硫化物基全固态锂电池的发展。本文首先从实验室研究阶段出发,从正极/电解质界面、硫化物电解质自身及负极/电解质界面三方面阐述了硫化物基全固态锂电池现阶段面临的主要问题,并介绍了相关的解决策略。随后从硫化物基全固态锂电池的实用化生产角度出发,介绍了电极/电解质膜的制膜工艺、软包电池的装配相关问题、高载正极的设计及硫化物电解质的大规模、低成本制备。最后展望了硫化物基全固态锂电池的未来研究方向和发展趋势。

摘要：抽蓄机组甩负荷工况下,整个过程水力矩剧烈波动,复杂的流态促成空化现象的发生,进而对流场造成更大的影响。本文主要基于多相流空化模型对原型水泵水轮机进行全过流系统甩荷过渡过程数值模拟,探究了空化现象的发生对机组瞬态过程的影响。结果表明,抽蓄机组甩负荷过程中空化现象主要有发生在靠近顶盖的叶片背面的翼型空化以及短时且高频发展与溃灭的空腔空化,并且发现了尾水管的涡带变化过程为:同心柱状-偏心螺旋-幕布状涡带,研究结果对抽蓄机组甩负荷运行稳定性具有参考意义。

摘要：为验证斜孔掏土应力解除法治理华东某双向偏斜生根井塔的适应性和有效性,综合理论分析、数值模拟和现场实测研究了斜孔掏土孔周塑性区发展、纠偏机制及掏土各因子对纠偏效果的影响规律。结果表明,开孔后孔周塑性区半径与孔径和孔周应力成正比,且随钻孔深度增加而增大。掏土纠偏的内在机制在于钻孔能有效解除孔周一定范围内的应力,使孔周土体不断向孔内坍塌,进而减小开孔侧井筒的外荷载,与对侧产生应力差值,促使井塔回纠。通过正交试验设计极差分析得出钻孔孔排宽度为影响掏土纠偏的最主要因子,其次为钻孔深度、孔径和孔距井筒中心线距离,且斜孔纠偏效果优于竖直孔。最后,基于模拟获得的最优纠偏参数组合设计了现场纠偏方案,并对井塔偏斜和井筒受力进行施工监测得出,斜孔掏土应力解除法有效逆止了生根井塔的偏斜发展,目前井塔偏斜和井壁受力均处于安全可控状态。