Dispersion and distribution of organically modified montmorillonite in nylon‐66 matrix

Nylon‐66 nanocomposites were prepared by melt‐compounding nylon‐66 with an alkyl ammonium surfactant pretreated montmorillonite (MMT). The thermal stability of the organic MMT powders was measured by thermogravimetric analysis. The decomposition of the surfactant on the MMT occurred from 200 to 500 °C. The low onset decomposition temperature of the organic MMT is one shortcoming when it is used to prepare polymer nanocomposites at high melt‐compounding temperatures. To provide greater property enhancement and better thermal stability of the polymer/MMT nanocomposites, it is necessary to develop MMT modified with more thermally stable surfactants. The dispersion and spatial distribution of the organic MMT layers in the nylon‐66 matrix were characterized by X‐ray diffraction. The organic MMT layers were exfoliated but not randomly dispersed in the nylon‐66 matrix. A model was proposed to describe the spatial distribution of the organic MMT layers in an injection‐molded rectangular bar of nylon‐66/organic MMT nanocomposites. Most organic MMT layers were oriented in the injection‐molding direction. Layers near the four surfaces of the bar were parallel to their corresponding surfaces; whereas those in the bulk differed from the near‐surface layers and rotated themselves about the injection‐molding direction. The influence of the spatial distribution of the organic MMT on crystallization of nylon‐66 was also investigated. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1234–1243, 2003     

Development of Full Automatic External Welding Machine for Annular Welds of Pipeline

To meet the demands of rapid development of pipeline constructions in China, a complete set of full automatic external welding machine for annular welds of pipeline and welding procedure have been developed thereof. The system has been applied in the “West-East Pipeline Project” and its performance is proven. With this welding machine the welding parameters can be either preset before or adjusted in real time during the welding process, which avoids the blemishes of same type domestic and international products. Thus it is best propitious to in-situ construction conditions and workers‘ technical level in China. In this article the development of mechanical and control systems of this product is introduced and typical welding procedure parameters are provided.     

筒型基础系缆平台沉／拔过程侧摩阻力原型测试

介绍了1999年首次安装在渤海锦州9－3地区多筒基础平台安装施工过程中的侧摩阻力原型测试研究，描述了简型基础上沉和上拔过程中筒壁侧摩阻力的测试系统和测试方法，给出了主要测试结果并与现行规范进行了对比分析，这项成果对筒型基础平台的设计和施工具有直接的参考意义。     

A new alternating‐direction finite element method for hyperbolic equation

A modified backward difference time discretization is presented for Galerkin approximations for nonlinear hyperbolic equation in two space variables. This procedure uses a local approximation of the coefficients based on patches of finite elements with these procedures, a multidimensional problem can be solved as a series of one‐dimensional problems. Optimal order H₀¹ and L² error estimates are derived. © 2007 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2007     

A new generalized algebra method and its application in the (2 + 1) dimensional Boiti–Leon–Pempinelli equation

In the present paper, some types of general solutions of a first-order nonlinear ordinary differential equation with six degree are given and a new generalized algebra method is presented to find more exact solutions of nonlinear differential equations. As an application of the method and the solutions of this equation, we choose the (2 + 1) dimensional Boiti Leon Pempinelli equation to illustrate the validity and advantages of the method. As a consequence, more new types and general solutions are found which include rational solutions and irrational solutions and so on. The new method can also be applied to other nonlinear differential equations in mathematical physics.     

我国中小企业现状及竞争前景

阐述并分析了我国中小型企业在发展中存在的问题。根据中小型企业自身的特点，提出中小型企业可以利用自身优势进行横向联合发展，并处理好成本、特色经营、产品创新之间的关系；树立风险意识，积极创新，扩大多渠道的融资等竞争策略，以适应WTO的全球经济化的需求。     

Adaptive regulation for deterministic systems

For the linear deterministic system with unknown orders and coefficients adaptive controls are given so that the closed-loop system is stabilized and the unknown parameters are consistently estimated. Moreover, if the parameter estimation is ignored, then the system input and output can be reduced to zero with an exponential rate.This project is supported by the National Natural Science Foundation of China.In Commemoration of the 15th Anniversary of the Acta Mathematicae Applicatae Sinica.     

吸附溶出伏安法测定毗喳酮的研究

本文报道了用吸附溶出伏安法测定毗喳酮.以悬汞电极为工作电极，在Na}B,O,-NaOH介质(pH=10)中，毗喳酮产生一尖锐的吸附还原峰,E，二一1. 29V (vs. SCE )，峰电流与毗喳酮浓度在2. 0 X 10-'-8. 0 X 10-smol " L-’范围内呈良好的线性关系.检测限为2. 0 X 10-0mol " L-'(富集90s).本文对毗喳酮在悬汞电极上的电化学行为进行了探讨，对测定毗喳酮的最佳条件进行了详细的选择，利用本法测定了片剂中毗喳酮含量，结果满意.     

甲醇催化脱氢制甲酸甲酯反应中Cu－ZnO－ZrO_2／SiO_2催化剂的特性

Ｃｕ－ＺｎＯ－ＺｒＯ２／ＳｉＯ２催化剂对甲醇催化脱氢制甲酸甲酯的反应具有良好的活性和选择性．应用连续微反、差示热分析、Ｘ射线衍射、程序升温还原、Ｘ射线光电子能谱分析和红外光谱等技术，对该催化剂的活性中心本质、ＺｎＯ及ＺｒＯ２的助催化作用、可能的反应机理以及催化剂的失活原因进行了探讨．     

层次分析法在城市土地分级中的应用

探讨了用层次分析法对城市土地等级进行定量评价的原理和方法，并以济南市为例进行实证研究，取得了较好的效果，为土地有偿使用和城市规划提供了依据。