采用非平衡态分子动力学方法模拟可极化纳米胶体在非均匀电场下的介电泳情况，通过改变电场强度和系统温度，分析纳米胶体的团聚现象。常温状态下的仿真结果表明，虽然布朗力能影响纳米胶体的介电泳状况，但当纳米胶体之间的距离小于12σ时，其相互吸引力迅速增大，从而克服布朗力影响，使胶体产生团聚。当布朗力对胶体运动影响较小时，电场强度增大使得胶体所受的介电泳力增大，相应地胶体所受的吸引力也增大，最终导致胶体的聚集速度变快。仿真结果也显示系统温度的升高使得胶体所受的布朗力增大，从而影响纳米胶体的团聚。最后，采用DLVO理论对相互作用的胶体运动状态进行研究，得出胶体的位能曲线图和胶体间吸引力随胶体中心距变化的曲线图，并将后者与分子动力学方法得出的结论进行对比，发现这两条曲线的变化趋势基本相同，这说明本文的仿真模型是符合理论的。

The ion distribution and electroosmotic flow of sodium chlorine solutions confined in cylindrical nanotubes with high surface charge densities are studied with molecular dynamics (MD). To obtain a more practical physical model for electroosmotic driven flow in a nanoscale tube, the MD simulation process consists of two steps. The first step is used to equilibrate the system and to obtain a more realistic ion distribution in the solution under different surface charge densities. Then, an external electric field is acted to drive the liquids. The simulation results indicate that with the increase of the surface charge density, both the thickness of the electric double layer and the peak height of the counterion density increase. However, the phenomenon of charge inversion does not occur even as the surface charge density increases to -0.34 C/m2, which is rather difficult to reach for real materials in practical situations. This simulation result confirms the recent experimental observation that monovalent ions of sufficiently high concentrations can reduce or even cancel the charge inversion occurred in the case of multivalent ions

在分析介电泳的微纳米生物粒子操纵研究现状和存在问题基础上，研究了基于光诱导介电泳的微纳米生物粒子操纵的理论基础和建模仿真，给出了光诱导介电泳芯片在空间电场分布和不同高度介电泳力分布关系。在此基础上进行微操纵系统的核心部件——光电导层芯片的选材、制作工艺和性能分析测试，给出了悬浮液层分压和有效电压频谱关系图。最后，组合机器视觉检测与实时跟踪子系统，构建了基于光诱导介电泳的微纳米生物粒子操纵实验平台，完成了对微纳米生物粒子快速聚集、输运、分离等操纵实验，为建立以微流控芯片为基础的重大疾病的快速、准确、低成本的检测和早期诊断提供了基础。

The application background and experimental research overview of medical endovascular stent are presented. Based on the analytical comparison of the current research achievements, the life cycle of medical vascular stent, which is composed of three phases of mounting, deployment and long-term in vivo service, is pointed out and the characteristics of stent expansion process in the life cycle are emphasized on. The experimental scheme of in vitro stent expansion based on the machine vision technology in LabVIEW is presented. The selected component devices and measurement program for experiment are expatiated. A special drug-loading stent was expanded on the assembled platform of selected equipments and experimental results are analyzed. The experimental scheme presented in the paper provides powerful experimental support for the computer simulation of stent expansion process by the finite element analysis.

Nonequilibrium molecular dynamics (MD) method was used to study the dielectrophoresis (DEP) mo-tion of nanocolloids in non-uniform electric field. By changing the electric field strength and system temperature, aggregation phenomena of nanocolloids was analyzed. Simulation results showed that at normal temperature, though the Brownian force can affect the motion of colloids, the attractive force will increase quickly with the distance between colloids down to 12σ, which makes colloids aggregate. When the Brownian force is weak to colloid's motion, for the enhancement of electric field strength, the DEP force of colloid will increase and so did the attractive force, which finally quickens the aggregate speed. Simulation results also showed that the temperature' enhancement will increase the Brownian force of colloids, hence disturbing the colloids aggregation. Moreover, the DLVO theory was used to study the motion of a pair of interactional colloids, both the potential energy and the attractive force versus distance of colloids were presented, then the latter graph was used to compare with another graph elicited by MD method. Results showed that the two graphs were nearly the same, indicating the MD model accorded with the theory.

On the basis of the research on the status and problems of micro/nano bio-particles manipulation using dielectrophoresis, the theoretical basis and the model simulation of micro/nano bio-particles manipu-lation using light-induced dielectrophoresis were discussed. The space distribution of electric field and dielectrophoresis forces in different heights were also obtained. On this basis, the core component of the micro manipulation system, that is, photoconductive layer of the chip, was completed in the mate-rial selection, fabricating process and performance analysis testing. Then the voltage drop of the sus-pension and the effective voltage frequency spectrum were obtained. Finally, by combining the ma-chine vision detection with real-time tracking system, the micro/nano bio-particles manipulation plat-form based on the light-induced dielectrophoreisis was established, and then the manipulations for micro/nano bio-particles, such as quick collection, transport, separation, were implemented. This pro-vided a basis for rapid, accurate, and low-cost detection of serious diseases based on the micro-fluidic biochip and early diagnosis.

自装配技术在物理、生物化学、MEMS以及纳米制造等领域得到了广泛应用，对该领域的研究显示出重要的应用前景和重大的理论价值，成为一个充满生机活力的热点。本文在阐述微器件自装配领域研究成果的基础上，重点介绍了应用毛细力、亲水（疏水）力作为驱动力实现微器件的二维和三维功能结构自装配过程，并指出了目前研究方法在纳米级微器件三维功能结构自装配中存在的问题，最后提出了综合应用介电泳力、毛细力及亲水（疏水）力实现纳米颗粒与三维基体自装配的方法。

The dependence of superlattice thermal conductivity on period length is investigated by molecular dynamicssimulation. For perfectly lattice matched superlattices, a minimum is observed when the period length is of the order of the effective phonon mean free path. As temperature decreases and interatomic potential strength increases, the position of the minimum shifts to larger period lengths. The depth of the minimum is strongly enhanced as mass and interatomic potential ratios of the constituent materials increase. The simulation results are consistent with phonon transmission coefficient calculations, which indicate increased stop bandwidth and thus strongly enhanced Bragg scattering for the same conditions under which strong reductions in thermal conductivity are found. When nonideal interfaces are created by introducing a 4% lattice mismatch, the minimum disappears and thermal conductivity increases monotonically with period length. This result may explain why minimum thermal conductivity has not been observed in a large number of experimental studies.