用H-W-ECR CVD系统实现氢化非晶硅薄膜在氢气环境下同时进行化学热退火和光诱导退火的研究

为了研究氢化非晶硅薄膜的稳定性，我们设计了一个在原子氢气氛中热退火的同时进行光诱导退火的实验(TLAH)。实验装置是由传统的微波电子回旋共振化学气相沉积系统改造而成为热丝辅助微波电子回旋共振化学气相沉积系统。为了对这一退火方法进行比较，对样品还进行了热退火、热退火同时进行光诱导退火。同时，为了定量地分析光电导衰退，我们假设光电导衰退遵循扩展指数规律：1/σph=1/σs-(1/σs-1/σ0)exp[-(t/τ)β]，这里扩展指数参数β 和时间常数 τ 可从与 lnt 的线性关系中截距和斜率得到, 式中光电导饱和值σs可以通过在对数坐标系中表示的光电导和光照时间关系进行高斯拟合得到。实验结果显示：TLAH 方法可以提高氢化非晶硅薄膜的稳定性、改善其微结构和光电特性，同时还发现，光学带隙明显减小、荧光光谱显著地朝着低能方向移动。     

稳定分散的纳米银溶胶的制备及其表征

Stable aqueous dispersive colloidal Ag nanoparticles were prepared by reducing silver nitrate with sodium borohydride in the presence of 3-mercaptopropionic acid. The formation process of the Ag nanoparticles was investigated by UV-Visible spectroscopy and transmission electron microscopy. The results show that the spherical and rodlike particles and aggregates are formed in the initial stage of the reaction， then the rodlike particles and aggregates are gradually decomposed into small spherical particles， and the final obtained Ag nanoparticles with an average size of 8 nm are in uniform shapes and narrow size distribution， and the colloid remains stable for more than one month， which makes it convenient for use in practice. The presence of capping agent plays an extra role over nanoparticles stabilization and morphology. The presence of capping agent on the surface of Ag nanoparticle is confirmed by the X-ray photoelectron spectroscopy. It is found that Ag nanoparticles are negatively charged in alkaline condition， whereas they are positively charged in acid condition. Electrosteric effect is responsible for their long-term stability.     

两步式放电改善反向开关晶体管开通特性研究

针对大功率半导体开关反向开关晶体管(RSD)由于预充不足造成的非均匀开通缺陷, 在直接预充放电工作电路的基础上, 设计了一种两步式放电工作电路. 根据RSD结构特点理论分析了正常开通所需条件, 并对器件元胞结构进行建模分析, 模型仿真结果表明RSD在窄脉宽预充电流作用下具有更佳的开通性能, 降低了预充阶段基区载流子复合. 两步式放电实验发现第一步放电电流幅值、脉宽对于两步式放电电路的正常工作起决定作用, 而反向预充电流主要作用于RSD第一步放电的正常开通, 降低了预充电路设计难度. 仿真及实验结果均表明两步式放电电路较直接式预充放电电路提高了RSD的均匀开通性能, 这是由于两步式放电显著提高了基区等离子体积累.     

Yb3+/Er3+共掺锗碲酸盐玻璃上转换发光增强机理的研究

玻璃的最大声子能量决定稀土离子的上转换发光强度，但本研究发现：Yb³⁺/Er ³⁺共掺锗碲酸盐玻璃在980nm LD抽运下，上转换荧光强度随着Bi₂O ₃对PbO的取代和碱 金属离子半径的增大而明显增强.而Raman光谱显示基质玻璃的最大声子能量并不随Bi ₂O₃对PbO的取代和碱金属离子半径的增大而变化，但玻璃的最大声子密 度随着Bi₂O₃对PbO 取代和碱金属离子半径的增大而降低.从玻璃无辐射跃迁概率的角度，通过分析表明，最大 声子密度的降低是玻璃上转换发光强度增强的主要原因.     

TeO2-ZnO-Na2O-K2O玻璃中Er3+离子掺杂浓度对其发光及荧光寿命的影响

测量了不同掺杂浓度下Er3+离子在碲酸盐玻璃中的吸收光谱、发射光谱和Er3+离子的荧光寿命,计算了Er3+离子的发射截面σe,分析了Er3+离子掺杂浓度对其发光强度和荧光寿命的影响.结果表明,Er3+离子掺杂浓度较低时,对其荧光强度和荧光寿命没有显著的影响;掺杂浓度高时,出现了浓度猝灭效应,使Er3+离子荧光光强度降低,荧光寿命下降.实验确定了掺杂浓度最优值,同时对浓度猝灭机制进行了分析.     

MWECR CVD等离子体系统梯度磁场对沉积a-Si:H薄膜特性研究

分别研究了磁场线圈电流为115.2和137.7A以及137.7A并在加热台下加放SmCo永磁体的方法，来改变单磁场线圈分散场MWECR CVD系统等离子体室及沉积室磁场形貌.用洛伦兹拟合定量地得到了三种磁场形貌的磁场梯度.研究了磁场梯度对沉积a-Si:H薄膜性能的影响.研究表明：在衬底附近，高的磁场梯度可以获得高的沉积速率；在温度不很高时，高的磁场梯度可得到光敏性较好的a-Si:H薄膜. 关键词： 梯度磁场 洛伦兹拟合 a-Si:H薄膜 MWECR CVD系统     

Further Study of A-Related Quantum Interference of H-State Diatomic on Collision-Induced Rotational Energy Transfer

In our previous theoretical studies [Meng-Tao Sun, Yong-Qing Lee, and Feng-Cai Ma, Chem. Phys.Left. 371 （2003） 342], we have reported the quantum interference on collision-induced rotational energy transfer on CO （A ^1 Π,v = 3） with inert gases, which originates from the difference between the two A-related collision potential energy surfaces. The interference angle, which measures the degree of coherence, is presented in this paper. Based on the time-dependent first order Born approximation, taking into account the anisotropic Lennard-Jones interaction potentials, the relation of the interference angle with the factors, including experimental temperature, partner, and rotational quantum number, are obtained. The changing tendencies with them are discussed. This theoretical model is important to understanding and performing this kind of experiment.     

Chaotic Control of Network Traffic

A method of chaotic control on network traffic is presented. By this method, the chaotic network traffic can be controlled to a pre-assigned equilibrium point according to chaotic prediction and the largest Lyapunov exponent of
the traffic on congested link is reduced, thereby the probability of traffic burst and network congestion can be reduced. Numerical examples show that this method is effective.     

An analytical model for coplanar waveguide on silicon-on-insulator substrate with conformal mapping technique

In this paper, the authors present an analytical model for coplanar waveguide on silicon-on-insulator substrate. The four-element topological network and the conformal mapping technique are used to analyse the capacitance and the conductance of the sandwich substrate. The validity of the model is verified by the full-wave method and the experimental data. It is found that the inductance, the resistance, the capacitance and the conductance from the analytical model show they are in good agreement with the corresponding values extracted from experimental S-parameter until 10 GHz.     

The differential interference angle in collisional quantum interference on rotational energy transfer

Collisional quantum interference （CQI） in the intramolecular rotational energy transfer was observed in experiment by Sha and co-workers. The interference angle, which measuring the degree of the coherence, were measured in the experiment of the static cell. Based on the first Born approximation of time dependent perturbation theory, taking into accounts the anisotropic Lennard-Jones interaction potentials, this paper describes the theoretical model of CQI in intramolecular rotational energy transfer in an atom-diatom collision system. In the model, the differential interference angle for the experiment of the molecular beam is calculated, the changing tendencies of the differential interference angle with the impact parameter and collision partners are obtained. This theoretical model is important for understanding or performing this kind of experiments.