4—氨基—1,8—萘二酰亚胺类荧光颜料研究

研究以苊为原料经硝化、氧化、脱水、缩合及还原反应合成N-芳基(脂基)取代的4-氨基-1,8-蔡二酰亚胺类荧光染料、颜料,结果表明以硝基萘酐先与芳胺、脂肪胺进行缩合反应工艺比以4-氨基-1,8-萘酐与胺类反应具有纯度、收率高等特点:比较不同还原方法对产物质量的影响及不同取代的芳基、脂基结构对其荧光特性的影响。     

玻色弦在推广GPS背景场中的运动

本文讨论了玻色弦在推广GPS背景场中的运动.结果表明玻色弦的轨迹为双锥曲线,形状由弦能量E~2与弦的等效质量μ~2决定.本文还考虑了磁单极催化"Winders"湮灭的可能性,并导出其条件.同时,本文导出了玻色弦在一般弯曲时空中的运动方程,为广义Lorentz方程、     

Effect of solidification rate on the coarsening behavior of precipitate in rapidly solidified Al-Si alloy

The gas-atomized Al-Si alloy powder with different particle sizes was subjected to isothermal annealing for understanding the effect of solidification rate on precipitation and growth Si crystals. The results show that Si precipitates grew more quickly in the small samples with a large solidification rate due to high interfacial energy. Moreover, these Si crystals had a tendency to form a quasi-spherical shape after annealing at a low temperature or for a short holding time. Coarsening of the Si precipitates during annealing was examined using a LSW equation. Thermal stability of the rapidly solidified alloy was significantly influenced by its original microstructure as a result of high solidification rate. Furthermore, more serious clustering of Si-Si phase was also observed in the small samples, attributed to the rapid coarsening of the Si phases.     

Forecasting using high‐frequency data: a comparison of asymmetric financial duration models

The first purpose of this paper is to assess the short‐run forecasting capabilities of two competing financial duration models. The forecast performance of the Autoregressive Conditional Multinomial–Autoregressive Conditional Duration (ACM‐ACD) model is better than the Asymmetric Autoregressive Conditional Duration (AACD) model. However, the ACM‐ACD model is more complex in terms of the computational setting and is more sensitive to starting values. The second purpose is to examine the effects of market microstructure on the forecasting performance of the two models. The results indicate that the forecast performance of the models generally decreases as the liquidity of the stock increases, with the exception of the most liquid stocks. Furthermore, a simple filter of the raw data improves the performance of both models. Finally, the results suggest that both models capture the characteristics of the micro data very well with a minimum sample length of 20 days. Copyright © 2008 John Wiley & Sons, Ltd.     

Explicit multisoliton solution to the coupled nonlinear Schrodinger equations

Based on the inverse scattering transform for the coupled nonlinear Schrodinger (NLS) equations with vanishing boundary condition (VBC), the multisoliton solution has been derived by some determinant techniques of some special matrices and determinants, especially the Cauchy-Binet formula. The oneand two-soliton solutions have been given as the illustration of the general formula of the multisoliton solution. Moreover, new nonsymmetric solutions corresponding to different number of zeros of the scattering data on the upper and lower half plane are discussed.     

现代租凭与其他信用形式的区别

现代租赁在经济社会中发挥着独特的作用，它和其他信用形式相比，具有特殊的优越性，现代租赁和传统租赁在租赁目的、当事人、涉及的合同、租赁物的选择权及其期末处理方式上不同；与银行信用在融资方式、融资额度、融资限制以及融次成本等各方面存在着差异；与商业信用的区别则在于物件所有权、对设备过时承担的风险以及税收等几个方向。     

金属／n型半导体（Au／n—GaN）肖特基势垒的研究

材料Au/nGaN在600度温度淬火后，利用电流－电压测量，XPS谱研究金Au和n型GaN半导体形成的接触势垒，电流－电压测量得到肖特基势垒平均高度和理想因子分别为1．24eV,1.03，理想因子为1．12的势垒最大高度为1．35eV，XPS数据表明：600度温度的淬火导致能带向上弯曲0．35eV，随着金的沉积在同一方向产生进一步的能带弯曲0．25eV，我们的结论可以用Cowley-Sze模型来解释，结合表明，在GaN表面有受主态密度。     

Perfluorooctane sulfonate (PFOS) and other fluorochemicals in viscera and muscle of farmed pigs and chickens in Beijing,China

Eleven perfluorinated compounds (PFCs) were determined in tissue samples from farmed pigs and chickens (n=143) that were purchased in Beijing in March 2009. The total PFCs mean concentration was the highest in pig liver (3.438 ng g^–1 wet weight (ww)), followed by pig kidney (0.508 ng g^–1 (ww)), pig heart (0.167 ng g^–1 (ww)), chicken liver (0.098 ng g^–1 (ww)), chicken heart (0.050 ng g^–1 (ww)), pork loin (0.018 ng g^–1 (ww)), and chicken breast (0.012 ng g^–1 (ww)). Among the PFCs analyzed, perfluorooctane sulfonate (PFOS) was the predominant compound in viscera and muscle of farmed pigs and chickens. In addition, a strong linear correlation (r = 0.932) was observed between the concentrations of PFOS and perfluoroundecanoic acid (PFUnDA) in pig liver. Our preliminary conclusion is that there is little potential risk of exposure to PFCs via the consumption of these products in Beijing.