Studies of Ziegler-type catalysts for the polymerization of ethylene and propylene II The polymerization of ethylene with VOCl3-Et3Al2Cl3 (chlorinated activator) catalysts

VOCl₃-Et₃Al₂C1₃(chlorinated activator) catalysts have been employed for the polymerization of ethylene at T between 15 and 85° in n-hexane. Using butylperchlorocrotonate as the activator, the following catalyst efficiencies (g polymerization, hr, atmosphere ethylene in the cap gas) were achieved: 10^6,1 MFI = 0-00; 10^5,8, e.g. MFI = 1 0 (with 9 per cent H₂ present in the cap gas) and 10^6–9 MFI = 0?4 (with 44 mmole/1 styrene in the hexane medium). Reactions between the aluminium alkyl and the activator molecules produced other chlorinated species of high average activator effectiveness. The catalyst system could be reactivated by further additions of Et₃Al₂Cl₃. The minimum value of the polymerization propagation rate constant is estimated to be 10¹²²?6x10,461 cm³/mole sec.     

Degradation of historical paper: nondestructive analysis by the NMR-MOUSE

The NMR-MOUSE is a mobile sensor for single-sided NMR inspection of organic materials which takes advantage of the principles of magnetic resonance and inside-out-NMR. Historical books dating from the 17th century were measured at different points by positioning the NMR-MOUSE on the paper. Different degrees of paper degradation can be discriminated from the regularized inverse Laplace transform of the envelope of the acquired echo signals. For the first time the degradation of historical paper was characterized entirely nondestructively by NMR. As a contribution to current preservation efforts, NMR shows great promise for future use in damage assessment of historical documents.     

基于遗传算法的自动组卷策略

自动组卷是一个多约束条件的最优求解问题,传统组卷算法存在速度慢、成功率低、组卷质量不高等不足,已不符合现行要求。为此,文中采用整段交叉,段内变异的方法,通过确定适应度函数和遗传算子探索了遗传算法在自动组卷中的应用,在一定程度上克服了已有算法的不足,并用算例验证了其有效性及适用性。     

基于asp的网上考试系统功能实现

根据网上考试系统的功能模块划分，用asp编程实现管理员注册、在线考试、时间控制、自动判卷、试题录入、修改题库、用户登录等重要功能，实现客观题的评阅工作。     

VALUE DISTRIBUTION THEORY AND DIOPHANTINE APPROXIMATION

In this paper, we will introduce some problems and results between Diophantine approximation and value distribution theory.     

数字海图编辑方法初探

本文在简述纸海图编辑的基础上，结合数字海图产生的背景并针对数导海图的特点，阐述了数字海图的编辑内容及表现方法，进一步提出了数字海图的编辑设想。从满足用户需求的角度，提出了对数字海图进行发展创新的理念。     

Bioactive paper provides a low-cost platform for diagnostics

Bioactive paper includes a range of potential paper-based materials that can perform analytical functions normally reserved for multi-well plates in the laboratory or for portable electronic devices. Pathogen detection is the most compelling application. Simple paper-based detection, not requiring hardware, has the potential to have impacts in society, ranging from the kitchen to disasters in the developing world. Bioactive-paper research is an emerging field with significant efforts in Canada, USA (Harvard), Finland and Australia.Following a brief introduction to the material and surface properties of paper, I review the literature. Some of the early work exploits the porosity of paper to generate paper-based microfluidics (“paperfluidics”) devices. I exclude from this review printed electronic devices and plastics-supported devices.     

"显示器无处不在"--介绍2004年IDW大会上的三篇报告

要从2004年12月在日本新滹举行的国际显示大会（IDW04）上发表的458篇论文中拿出相当数量的一小部分来讨论是一件难事，因此我们在这里仅仅集中讨论其中三篇文章里所提出的议题。     

A(∞)TH上的辫子Monoidal范畴

Let A and H be Hopf algebra,T-smash product A (∞)T H generalizes twisted smash product A*H.This paper shows a necessary and sufficient condition for T-smash product module category A(∞)T H M to be braided monoidal category.