航空胶片冲洗机直流电机调速控制系统设计

针对航空胶片冲洗机控制困难表现其电机负载不均匀，低速运行情况下电机震动剧烈．研制了专用的反馈控制系统．以双89C51单片机为核心组成控制电路，编写了系统操作程序和数字PID控制程序．对PID参量对控制系统稳定性的影响进行了分析，得出适应于本系统的PID控制规律，并经过大量的试验，获得了能使各档速度稳定运行下的PID控制参量．实践表明，该控制系统运行稳定可靠，低速控制准确度在3％以内，中高速准确度达到1％．     

强激光装置中玻璃疵病在线检测的光学系统设计

介绍了一种用于玻璃疵病在线检测的近摄工作距成像光学系统,其光组结构形式采用了光阑后置的准远心结构形式,主要光学参量为f′=14 mm;在物像距为250 mm约束条件下,物方视场达到90 mm（对角线）;F/number=3.56;光谱适应范围为400~800 nm,对应的空间分辨率为100 lp/mm时,调制传递函数大于0.29.     

二氧化钛分子电致发光激发特性研究

采用密度泛函B3P86方法优化得到了沿分子平面不同外电场作用下TiO₂分子的基态稳定构型, 在优化构型下利用杂化CIS (CI-Singles)-B3P86方法在6-311＋G*基组水平上, 研究了不同外电场下TiO₂分子前六个激发态的激发能和跃迁波长等激发特性. 研究结果表明, TiO₂分子多个激发态满足偶极跃迁定则, 跃迁光谱对应多个峰值, 在分子水平上, 可以增大利用太阳光的比例. 在外电场作用下, 能隙随电场的增大而减小, 电子易从最高占据轨道跃迁到最低空轨道形成空穴, 各个激发态跃迁波长均有随电场增大发生红移的趋势, 最长589 nm, 因而利用外电场可以控制材料的发光光谱范围在可见光区域扩展.     

光电系统的匹配设计

通过对光电系统中探测器对图像采样的分析,由瑞利判别给出了光学系统-探测器匹配的原则:即瑞利斑的直径等于探测器像元中心距的大小,并分析了系统的MTF;通过分析系统的信息传递关系,给出了电子图像重建系统带宽的设计原则.     

Combined stress waves with phase transition in thin-walled tubes简

The incremental constitutive relation and governing equations with combined stresses for phase transition wave propagation in a thin-walled tube are established based on the phase transition criterion considering both the hydrostatic pressure and the deviatoric stress. It is found that the centers of the initial and subsequent phase transition ellipses are shifted along the σ-axis in the στ-plane due to the tension-compression asymmetry induced by the hydrostatic pressure. The wave solution offers the "fast" and "slow" phase transition waves under combined longitudinal and torsional stresses in the phase transition region. The results show some new stress paths and wave structures in a thin-walled tube with phase transition, differing from those of conventional elastic-plastic materials.     

First-Principles Calculations of Elastic and Thermal Properties of Lanthanum Hexaboride

The plane-wave pseudopotentiai method using the generaiized gradient approximation within the framework of density functional theory is applied to anaylse the bulk modulus, thermal expansion coefficient and heat capacity of LaB6. The quasi-harmonic Debye model, using a set of total energy versus volume obtained with the plane-wave pseudopotential method, is applied to the study of the thermal properties and vibrationai effects. We analyse the bulk modulus of LaB6 up to 1500 K. The elastic properties calculations show that our system is mechanically stable. For the heat capacity and the thermal expansion, significant differences in properties are observed above 300K. The calculated zero pressure bulk modulus is in good agreement with the experimental data. Moreover, the Debye temperatures are determined from the non-equilibrium Gibbs functions and compared to available data.     

加载路径和温度对NiTi合金相变特性的影响

利用MTS装置,对NiTi形状记忆合金在不同加载路径(拉、压、扭以及拉/压-扭比例加载)和不同温度(28~150℃)下的准静态相变行为进行了较系统的实验研究。结果表明,材料呈现明显的伪弹性效应和拉压不对称性。随着温度的升高,相变起始应力逐渐增大,伪弹性效应和拉压不对称性逐渐减弱。当温度达到一定阈值时,拉压不对称性消失,材料基本呈现弹塑性状态。通过实验曲线确定了NiTi合金的相变临界参数,在σ-τ应力空间中对三种常用宏观相变临界准则进行了讨论,比较了它们各自的适用性。     

Pseudo-potential investigations of structural, elastic and thermal properties of tungsten disilicide

The plane-wave pseudopotential method using the generalized gradient approximation within the density functional theory is used to investigate the structure and bulk modulus of WSi₂. The quasi-harmonic Debye model, using a set of total energy versus cell volume obtained with the plane-wave pseudopotential method, is applied to the study of the elastic properties and vibrational effects. We have analysed the bulk modulus of WSi₂ up to 1600~K. The major trend shows that the WSi₂ crystal becomes more compressible when the temperature rises and the increase of compressibility leads to the decrease of Debye temperature. The predicted temperature and pressure effects on the thermal expansion, heat capacity and Debye temperatures are determined from the non-equilibrium Gibbs functions and compared with the data available.     

采用可见光源和分划板快速装调激光光路

 分析了激光测量光路的特点和装校要求,给出了采用可见光源、分划板装校激光光路的原理。以预放测量模块为例,介绍了装校的流程及装校中的注意事项,分析了装校所能达到的精度,并用内调焦望远镜进行了装校精度检查。结果表明,采用可见光源、分划板装校的激光光路透镜光轴正过心的偏心极限误差小于等于0.07 mm,光轴倾斜极限误差小于等于25″。     

水相凝胶色谱仪的改装与应用

凝胶色谱是一种用途广泛的液相色谱。在生物化学与高分子化学研究中,是测定分子量及其分布的一种重要方法。国内常见的几种凝胶色谱仪,如:Waters GPC-200、SN-01A型,这类仪器结构简单,容易操作,但是通常多用于有相溶剂相中测定,并且对