Halogen Bonding： An AIM Analysis of the Weak Interactions

A series of complexes formed between halogen-containing molecules and ammonia have been investigated by means of the atoms in molecules （AIM） approach to gain a deeper insight into halogen bonding. The existence of the halogen bond critical points （XBCP） and the values of the electron density （Pb） and Laplacian of electron density （V2pb） at the XBCP reveal the closed-shell interactions in these complexes. Integrated atomic properties such as charge, energy, polarization moment, volume of the halogen bond donor atoms, and the corresponding changes （△） upon complexation have been calculated. The present calculations have demonstrated that the halogen bond represents different AIM properties as compared to the well-documented hydrogen bond. Both the electron density and the Laplacian of electron density at the XBCP have been shown to correlate well with the interaction energy, which indicates that the topological parameters at the XBCP can be treated as a good measure of the halogen bond strength In addition, an excellent linear relationship between the interatomic distance d（X…N） and the logarithm of Pb has been established.     

一种基于灰度变换的红外图像增强算法

针对红外图像，采用双门限分割法进行图像分割，然后采用分段灰度变换法进行图像增强。根据具体图像，通过人机交互的方式确定2个阈值，将图像分割为目标区、过渡区和背景区3部分；按照每一部分的特点，设计不同的灰度变换，对图像进行分段线性增强，得到感兴趣目标区的最佳视觉效果。通过对16位红外图像进行实验，得到了满意的结果。实验表明,该算法灵活便捷，在增加对比度和去除噪声的同时，还抑制了背景，达到了预期的效果。     

全气相化学激光体系的直流放电研究

 为了提高化学激光体系(AGIL)中F原子的产率，采用直流放电引发方式，对棒式电极的放电特性进行了研究。在对NF3/He混合气体进行解离时，通过选择不同平衡电阻，得到了3 kW左右的放电注入功率。用光谱分析仪对F原子产率进行了测量。通过拟合计算可得：一个NF3分子能够解离出1.3～1.5个F原子。     

CRT显示器稳定性实验研究

用屏幕色度计对一台SONY-G520显示器的显色特性进行了测量,研究了其开机稳定性和短、中、长期内的色差及色度偏差。实验结果表明,开机后,显示器的亮度Y和色度x,y分别可在2h,30min和1h达到相对稳定状态,且在达到相对稳定后,在短、中、长期内的平均色差分别为0.0611,0.1469和1.2536CIELAB色差单位;在中期内,Y,x,y,L,a,b的平均偏差分别为0.0663,0.0008,0.0015,0.0695,0.4740和0.1766。通过对显示器稳定性的测量,为在对比度敏感测量和色貌模型、图像质量、图像感知模型评价等研究领域中用显示器进行实验研究奠定了基础。     

Absorption Complex between Porphyrin and Phenothiazine in Reverse Micelles

Porphyrin derivatives attract much more interest in photodynamic therapy (PDT). Their importance as therapeutic drugs and targeting agents has been widely recognized1, and many of the efforts have been put towards crafting new porphyrin-based molecular entities to achieve enhanced tumor localization, better tissue penetration and increased singlet oxygen quantum yield2. The states of porphyrins in tissue models such as micelles, lipid bilayers are extensively investigated focusing more or l…     

基于模糊聚类的语音识别

指出模糊聚类方法影响语间识别的正确率 ,提出用基于分解构造的模糊聚类方法设立语音模式的参考向量 ,说明该方法能提高语章识别的正确率。     

无催化纳米氧化锌的制备及其光学性质研究

本文采用无催化剂直接蒸发高纯Zn粉,在800℃氧气氛条件下,在Si(111)衬底上生长得到以四角状为主的纳米ZnO(T-ZnO)。T-ZnO纳米线每个角约互成110°,长度约为1.5μm,直径100nm左右;Raman分析表明E2(H)普遍存在于各形态的ZnO;光致发光光谱表明,T-ZnO纳米线的光致发光除了与材料性质有关,还与杂质缺陷有关,蓝绿光带是ZnO的缺陷产生的。     

Spectral Representation Theory for Dielectric Behavior of Nonspherical Cell Suspensions

Recent experiments revealed that the dielectric dispersion spectrum of fission yeast cells in a suspension was mainly composed of two sub-dispersions. The low-frequency sub-dispersion depended on the cell length, while the high-frequency one was independent of it. The cell shape effect was simulated by an ellipsoidal cell model but the comparison between theory and experiment was far from being satisfactory. Prompted by the discrepancy, we proposed the use of spectral representation to analyze more realistic cell models. We adopted a shell-spheroidal model to analyze the effects of the cell membrane. It is found that the dielectric property of the cell membrane has only a minor effect on the dispersion magnitude ratio and the characteristic frequency ratio. We further included the effect of rotation of dipole induced by an external electric field, and solved the dipole-rotation spheroidal model in the spectral representation.Good agreement between theory and experiment has been obtained.     

用区域分解算法结合蒙特卡罗法求坦克温度场和红外辐射出射度

本文将区域分解算法和蒙特卡罗法相结合，求坦克温度场和红外辐射出射度．采用蒙特卡罗法计算辐射传递系数，可以考虑界面的复杂辐射特性，如：镜反射、各向异性发射、各向异性反射等；可直接考虑界面的复杂几何特性，如:相互遮挡、太阳入射方向上的投影面积等．引入辐射传递系数，分离了计算的难点，使得在时间域（计算步骤）上能把整个问题分解为若干个子问题并行处理、在空间域（计算区域）上将坦克分解为若干个子区域，缩小计算规模，并可使用多个处理器并行计算；同时减轻了蒙特卡罗法编程的难度，缩短了计算时间．     

Tl2Ba2Ca2Cu3Oy超导体磁通钉扎能的分布

描述一种测量高温超导体磁通钉扎能U₀及其分布的新方法,此方法主要之点是测量磁化后样品的零场临界电流随时间的变化,利用这一方法测量Tl₂Ba₂Ca₂Cu₃O_y的U₀值分布(T=78K)。根据所得结果,对已报道的U₀值的分散性提出一种新解释。 关键词：