16 keV C–离子在锥形玻璃管中的输运过程

鉴于经锥形玻璃管聚焦的离子束在微纳加工、微区分析以及辐照生物医学等领域具有广阔的应用前景,本文研究了16 keV C^–在不同倾斜角度的锥形玻璃管中输运过程.实验发现当处于0°倾斜角度时,出射粒子由核区和晕区构成,核区是从锥形管后锥孔中直接出射,未与锥形管内壁之间发生电荷交换,主要成分为C^–离子.晕区是C^–与锥形管内壁发生部分电荷交换作用,由C^–和C⁰构成.当倾斜角度为1°时,出射离子由两部分组成:C⁰原子束斑和C^–离子束斑,未出现核区.出射核区的离子方向始终保持在入射粒子方向,与锥形管倾斜角度无关.随着锥形管不断倾斜,相对透射率不断减小, C⁰束斑占比增加, C^–束斑占比减小.锥形管对入射离子有聚焦效应.本实验弥补了低能负离子在锥形管运输过程研究的欠缺,有助于聚焦离子束的后续开发应用.     

网球塔的理论分析与实验探究

借助网球之间的摩擦力,可以将网球垒成多层的“网球塔”.“网球塔”问题兼具趣味性、科学性和综合性,研究该问题对锻炼大学生的综合物理素养有重要意义.本文首先以形变程度和接触面积两方面的实验验证了所选网球可以视为刚体;其次,考虑网球条纹等因素测出了球上静摩擦因数与支持力间的关系,进一步给出了稳定网球塔的理论力学分析求解方法,并结合Adams仿真与实际实验进行了验证;最后,指出除顶层外,各层的球数都相同时,可通过改变球的堆积密度和构建“耦合”结构两种方式改变网球塔的结构,并讨论了相关求解中的超静定问题.     

The effect of the rotational excitation of NO on the stereodynamics for the reaction C(~3P)+NO(X~2Π)→CN(X~2Σ~+)+O(~3P)

The stereodynamic properties of the reaction C(3P)+NO(X2Π)→CN(X2Σ+)+O(3P) in different rotational states of reactant NO are studied theoretically by using the quasiclassical trajectory method on 2A' and 2A' potential energy surfaces(PESs) at a collision energy of 0.06 eV.The vector properties in different rotational states on the two surfaces are discussed in detail.The results indicate that the rotational excitation of NO has considerable influence on the stereodynamic property of the reaction occurring on the two surfaces.At the same time,the calculated polarization-dependent differential cross sections(PDDCSs) in different initial rotational states manifest that products are strongly polarized at three scattering angles.     

仿射变换内点信赖域方法求解变分不等式问题

本文研究了求解非线性约束变分不等式问题(VIP)的一个新的算法.利用KKT条件的非光滑方程形式,得到了与VIP等价的简单约束优化问题.提出了求解VIP的一类结合回代线搜索技巧的仿射变换内点信赖域算法.在较弱的条件下证明了算法具有整体收敛性,进一步在某些正则条件下,证明了算法具有超线性收敛速度.     

火焰原子吸收光谱法测定6种动物鲜肉中的微量元素的含量

采用HNO3-HClO4(体积比为4∶1)消化体系,在常压微沸消解条件下,用火焰原子吸收光谱法(FAAS)测定了天水市市售6种鲜肉(猪、鸡、牛、羊、鲤鱼、牛蛙)中Zn、Cu、Fe、Mn的含量.结果表明,Zn、Cu、Fe、Mn在6种鲜肉中的含量均差异极显著(P＜o.01);将6种鲜肉按动物类别分为3类:即单胃动物(猪、鸡)鲜肉、反刍动物(牛、羊)鲜肉和水产动物(鲤鱼、牛蛙)鲜肉,结果显示:不同动物类别鲜肉中Zn含量差异极显著(P＜0.01),Cu、Fe含量差异显著(P＜0.05);相关性分析表明,6种鲜肉中Zn和Cu含量呈极显著负相关(P＜0.01); Zn与Mn含量呈显著正相关(P＜0.05);Cu与Mn含量呈显著负相关(P＜0.05);Fe和Mn含量呈极著正相关(P＜0.01).     

车载惯性定位定向系统可靠性设计分析与试验验证

本文针对某型车载惯性定位定向系统,建立产品的可靠性数学模型,进行可靠性分配和可靠性预计,介绍保证产品可靠性采取的技术措施,以及可靠性验证的试验方案和试验结果。     

初始呼吸子对Sine-Gordon系统动力行为的影响

研究了简谐外力扰动下,计入Peierls-Nabarro力和固体粘性效应,在Neumarm边界条件下杆的运动,这个运动可以用Sine-Gordon型方程来模拟．通过有限差分将无穷维的Sine-Gordon型系统近似为有限维系统．当外力的幅值和初始条件中呼吸子的相位发生变化时,系统的解呈现出丰富的空间结构和时间行为,对于一定的外力幅值和相位,系统具有混沌解．发现初始呼吸子的相位也是影响系统运动状态的重要因素。     

信赖域策略的内点投影既约Hessian方法解非线性约束优化

A interior point scaling projected reduced Hessian method with combination of nonmonotonic backtracking technique and trust region strategy for nonlinear equality constrained optimization with nonegative constraint on variables is proposed. In order to deal with large problems,a pair of trust region subproblems in horizontal and vertical subspaces is used to replace the general full trust region subproblem. The horizontal trust region subproblem in the algorithm is only a general trust region subproblem while the vertical trust region subproblem is defined by a parameter size of the vertical direction subject only to an ellipsoidal constraint. Both trust region strategy and line search technique at each iteration switch to obtaining a backtracking step generated by the two trust region subproblems. By adopting the l1 penalty function as the merit function, the global convergence and fast local convergence rate of the proposed algorithm are established under some reasonable conditions. A nonmonotonic criterion and the second order correction step are used to overcome Maratos effect and speed up the convergence progress in some ill-conditioned cases.     

Multiple Solutions of Laminar Flow in Channels with a Transverse Magnetic Field

We present a numerical investigation for steady laminar flow of a viscous incompressible electrically conducting fluid through a channel of a rectangular cross-section with a transverse magnetic field and suction or injection wails. Multiple solutions are presented for values of suction Reynolds number R and velocity coefficients of accelerating walls. Additionally, the associated transfer characteristics are discussed in detail.     

双折射器件对机载激光雷达偏振探测影响的研究

根据膜层理论给出了机载激光雷达回波信号垂直入射偏振棱镜时偏振平行分量透过率的数学解析表达式,定量分析了偏振棱镜对机载激光雷达回波信号平行分量透过率的影响,理论计算表明：棱镜晶体厚度、空气膜层厚度及棱镜结构角共同影响回波信号通过偏振棱镜的透过率;当回波信号波长为532 nm,利用1/2石英波片测得的偏振平行通道和偏振垂直通道的增益比k为1.2时,机载激光雷达偏振通道增益比k的真实值在1.003～1.463之间,若不考虑1/2波片对k值的影响,会给退偏振比反演带来较大的系统误差.