GaAs原子层外延技术的现状及发展

综述了原子层外延(ALE)技术的现状及其发展趋势。研究了晶体生长的程序设计和实验装置、生长的动力学模型及反应机制。对ALE薄膜的组成和结构进行了Raman和质谱分析。采用SPA原位诊断技术控制ALE的晶体生长,可有效地实现选择外延和图形化的晶体生长。大量实验表明:ALE技术可以实现原子级尺寸的超薄层晶体外延生长。用此技术已成功地研制出GaAs/GaAlAs量子阱器件。     

McKean-Vlasov limit for interacting random processes in random media

We apply large-deviation theory to particle systems with a random mean-field interaction in the McKean-Vlasov limit. In particular, we describe large deviations and normal fluctuations around the McKean-Vlasov equation. Due to the randomness in the interaction, the McKean-Vlasov equation is a collection of coupled PDEs indexed by the state space of the single components in the medium. As a result, the study of its solution and of the finite-size fluctuation around this solution requires some new ingredient as compared to existing techniques for nonrandom interaction.     

氮杂多环芳烃~（13）C－NMR化学位移的理论探讨

本文主要是对氮原子以ｓｐ~２杂化，孤氮电子占据ｓｐ~２杂化轨道，以这种形式成键的氮杂交变多环芳烃中的１１个化合物的~（１３）Ｃ－ＮＭＲ的化学位移进行了计算。该计算依据ＣＮＤＯ方法一个联系分子电荷密度，键级和键长等参数的半经验公式。同时利用环电流、空间效应以及针对氮原子的屏蔽效应和去屏蔽效应的影响，通过分子动力学的考虑，得到理论上计算的化学位移，该计算结果与实验值吻合得很好，通过时~（１３）Ｃ－ＮＭＲ化学位移的回归分析表明，回归系数达到０．９９，非常好地反映了氮杂多环芳烃~（１３）Ｃ－ＮＭＲ化学位移与分子微观结构之间的关系，同时表明我们在处理诸多化学位移时考虑到的因素是合理可行的。     

Navier－Stokes方程的变网格非协调有限元法

本文通过所谓的速度－压力型公式讨论了Ｎａｖｉｅｒ－Ｓｔｏｋｅｓ方程的变网格非协调有限元逼近，得到了在确定模意义下的速度、压力误差估计，且在一定条件下，某些误差估计能达到最优。     

SiGe HBT大信号等效电路模型

基于SiGe HBT(异质结双极晶体管)的物理模型，建立了描述SiGe HBT的大信号等效电路模型.该等效电路模型考虑了准饱和效应和自热效应等，模型分为本征和非本征两部分，物理意义清晰，拓扑结构相对简单.该模型嵌入了PSPICE软件的DEVEO(器件方程开发包)中.在PSPICE软件资源的支持下，利用该模型对SiGe HBT器件进行了交直流特性模拟分析，模拟结果与理论分析结果相一致，并且与文献报道的结果符合较好. 关键词： SiGe HBT 等效电路模型 PSPICE     

基于模糊语言判断矩阵和FIOWA算子的有限方案决策法

定义一种模糊的导出有序加权平均(FIOWA)算子，给出方案之间比较的模糊语言标度。运用模糊语言标度构造出模糊语言判断矩阵，并提出一种基于模糊语言判断矩阵和FIOWA算子的有限方案决策方法。该法利用FIOWA算子对模糊语言信息进行集结，并利用已有的三角模糊数排序公式求得决策方案的排序。     

Contribution of UV light to the decomposition of toluene in dielectric barrier discharge plasma/photocatalysis system

The contribution of UV light from plasma and an external UV lamp to the decomposition of toluene in a dielectric barrier discharge (DBD) plasma/UV system, as well as in a plasma/photocatalysis system was investigated. It was found that UV light from the DBD reactor was very weak. Its contribution to the removal of toluene in the plasma/photocatalysis system could be ignored. Whereas, the introduction of external UV light to the plasma significantly improves the removal efficiency of toluene by 20%. The removal efficiency of toluene in the plasma/photocatalysis system increased about 22% and 16% when compared with a plasma only system and plasma driven photocatalyst system, respectively. The increased toluene removal efficiency was mostly attributed to the contribution of the synergy between plasma and UV light, but not to the synergy between plasma and photocatalysis. The synergetic effect between plasma and photocatalysis was not significant.     

Sensory nerve recording for closed-loop control to restore motorfunctions

A method is developed for using neural recordings to control functional electrical stimulation (FES) to nerves and muscles. Experiments were done in chronic cats with a goal of designing a rule-based controller to generate rhythmic movements of the ankle joint during treadmill locomotion. Neural signals from the tibial and superficial peroneal nerves were recorded with cuff electrodes and processed simultaneously with muscular signals from ankle flexors and extensors in the cat's hind limb. Cuff electrodes are an effective method for long-term chronic recording in peripheral nerves without causing discomfort or damage to the nerve. For real-time operation the authors designed a low-noise amplifier with a blanking circuit to minimize stimulation artifacts. They used threshold detection to design a simple rule-based control and compared its output to the pattern determined using adaptive neural networks. Both the threshold detection and adaptive networks are robust enough to accommodate the variability in neural recordings. The adaptive logic network used for this study is effective in mapping transfer functions and therefore applicable for determination of gait invariants to be used for closed loop control in an FES system. Simple rule-bases will probably be chosen for initial applications to human patients. However, more complex FES applications require more complex rule-bases and better mapping of continuous neural recordings and muscular activity. Adaptive neural networks have promise for these more complex applications     

Comparison of conventional extraction under reflux conditions and microwave-assisted extraction of oil from popcorn.

Popcorn offers an environmentally friendly alternative to the commercial synthetic loose-fill packing materials. Popcorn could be used for cushioning purposes if the oil is extracted after the popping process. Conventional and microwave-assisted extraction methods were used for oil extraction from whole and ground, popped and unpopped kernels. The conventional extraction method achieved 68.5% oil recovery from whole popped kernels. However, whole unpopped kernels were not efficiently de-oiled with either of the methods. Extraction of oil from popped kernels is recommended; corn varieties with higher starch content and lower oil content should be used.     

激发能升高级联裂变到瞬发多重碎裂的演化

分析⁴⁰Ar+¹⁵⁹Tb、¹⁹⁷Au、²⁰⁹Bi(25MeV/u)中心碰撞产生的三体碎片产物的角关联,配合Ar+Au(60MeV/u)三体出射的数据,分析非完全熔合反应产生的高激发核衰变的演化过程,证明了在25MeV/u入射能时激发核产生的三重大质量碎片是级联的两次出射的裂变形成的,其时间差尺度大约为1000fm/c,而对60MeV/u入射能下的激发核观察到重碎片在120°附近出现强的角关联,这在理论上解释为发射时间差较短,即出现了瞬发的多重碎裂.