科创中国

采用B3LYP/6.31G**方法在Gaussian03程序下,对Corrole(CH3)和Corrolazine(C2H3)体系进行结构优化和振动分析.结果显示,CH3和C2H3的不同构型稳定性差异可忽略不计,结构参数的变化则说明中心空穴的大小顺序为PH2〉CH3〉PzH2〉C2H3.优化不同构型间相互转化的IHAT反应的过渡态,并进行相关的比较计算,发现CH3和C2H3的正反应速率都明显大于PH2和P2H2;同时CH3和C2H3的非平面构型的电子效应远大于PH2和P2H2的平面离域体系的平均化电子效应.

The electric fields employed for such work are generated using chips,such as planar linear interdigitated arrays or two parallel arrays.However,chip geometries usually affect the investigation of dielectrophoresis(DEP)and electrorotation(ER)significantly,and even may misdirect the theoretical prediction.In order to understand the electrodes geometries effect and provide a suitable range of parameters,three-dimensional simulations for the DEP and ER characterizations on the quadrupolar hyperbolical electrodes are carried out.Influences of the electrodes gaps,cell height,work region,energized voltage and frequencies for the DEP and ER manipulations are analyzed,and the analysis results show that the gaps of the electrodes and the cell height have enormous effects,but the work region is not so important.Moreover,depending on the theoretical analysis,ER experiments for polystyrene microspheres with the diameter of 20 m are carried out on two kinds of chips.The experimental results show that the microspheres rotate in the counter-field direction and the maximum rotation speed appears in the megahertz range.In addition,the experimental results are compared with the simulation results,showing that the three-dimensional simulations considering the chip geometries are more accurate than the two-dimensional predictions.This paper provides a new understanding for the theoretical predictions of DEP and ER manipulations,which decreases the difference of the theoretical and experimental results significantly,and will be significant for the lab chip research.

Most researches focused on the analytical stabilized algorithm for the modular simulation of single domain,e.g.,pure mechanical systems.Only little work has been performed on the problem of multi-domain simulation stability influenced by algebraic loops.In this paper,the algebraic loop problem is studied by a composite simulation method to reveal the internal relationship between simulation stability and system topologies and simulation unit models.A stability criterion of multi-domain composite simulation is established,and two algebraic loop compensation algorithms are proposed using numerical iteration and approximate function in multi-domain simulation.The numerical stabilized algorithm is the Newton method for the solution of the set of nonlinear equations,and it is used here in simulation of the system composed of mechanical system and hydraulic system.The approximate stabilized algorithm is the construction of response surface for inputs and outputs of unknown unit model,and it is utilized here in simulation of the system composed of forging system,mechanical and hydraulic system.The effectiveness of the algorithms is verified by a case study of multi-domain simulation for forging system composed of thermoplastic deformation of workpieces,mechanical system and hydraulic system of a manipulator.The system dynamics simulation results show that curves of motion and force are continuous and convergent.This paper presents two algorithms,which are applied to virtual reality simulation of forging process in a simulation platform for a manipulator,and play a key role in simulation efficiency and stability.

Most researches on the static performance of stiffened panel joined by friction stir welding(FSW) mainly focus on the compression stability rather than shear stability. To evaluate the potential of FSW as a replacement for traditional rivet fastening for stiffened panel assembly in aviation application, finite element method(FEM) is applied to compare compression and shear stability performances of FSW stiffened panels with stability performances of riveted stiffened panels. FEMs of 2024-T3 aluminum alloy FSW and riveted stiffened panels are developed and nonlinear static analysis method is applied to obtain buckling pattern, buckling load and load carrying capability of each panel model. The accuracy of each FEM of FSW stiffened panel is evaluated by stability experiment of FSW stiffened panel specimens with identical geometry and boundary condition and the accuracy of each FEM of riveted stiffened panel is evaluated by semi-empirical calculation formulas. It is found that FEMs without considering weld-induced initial imperfections notably overestimate the static strengths of FSW stiffened panels. FEM results show that, buckling patterns of both FSW and riveted compression stiffened panels represent local buckling of plate between stiffeners. The initial buckling waves of FSW stiffened panel emerge uniformly in each plate between stiffeners while those of riveted panel mainly emerge in the mid-plate. Buckling patterns of both FSW and riveted shear stiffened panels represent local buckling of plate close to the loading corner. FEM results indicate that, shear buckling of FSW stiffened panel is less sensitive to the initial imperfections than compression buckling. Load carrying capability of FSW stiffened panel is less sensitive to the initial imperfections than initial buckling. It can be concluded that buckling loads of FSW panels are a bit lower than those of riveted panels whereas carrying capabilities of FSW panels are almost equivalent to those of riveted panels with identical geometries. Finite element method for simulating static performances of FSW and riveted stiffened panels is proposed and evaluated and some beneficial conclusions are obtained, which offer useful references for analysis and application of FSW to replace rivet fastening in aviation stiffened panel assembly.

针对为胶囊内窥镜供能的无线能量传输技术在应用过程中对人体组织可能造成伤害的问题,进行了无线能量传输系统发射线圈优化设计研究.分析了人体组织安全性与无线能量传输系统发射线圈之间的关系,提出用磁场均匀度、频率稳定度等指标来评价发射线圈性能,并建立了以能量传输效率为目标函数、以人体安全性和能量需求为约束条件的最优化模型.该模型可用来全面评价发射线圈性能,从而为发射线圈的设计提供依据.采用上述方法对4种类型的发射线圈进行了评价,评价结果证明了该方法的可行性.