油田用聚合醇化学剂研究与应用

综述了聚合醇作为油田化学荆的研发和应用。论述了聚合醇在钻井液中的性能：抑制防塌性；润滑性；消泡性；无毒环保性。讨论了在钻井液中的抑制机理：浊点效应；降低滤液渗透能力；在黏土矿物上竞争吸附；与无机盐的协同效应。介绍了7种含聚合醇的钻井液及其应用效果：甲酸盐／正电聚醇钻井液、聚合醇／正电胶聚合物钻井液、铝盐聚合醇钻井液、聚合醇饱和盐水钻井液、小阳离子／聚合醇钻井液、聚醚多元醇钻井液、充氮气多元醇防塌钻井液。还介绍了用作酸化液助排剂和蒸汽吞吐井地层预处理剂的两种聚合醇的应用情况。参23。     

Optimization of product configuration design using functional requirements and constraints

We consider the general problem of designing mechanical parts moving in contact under the influence of externally applied loads. Geometrically, the problem may be characterized in terms of a conjugate triplet, which is formed by the two shapes moving in contact and their relative motion. We show that every such triplet belongs to one or more classes of functionally equivalent designs that may be represented uniquely by maximal triplets, corresponding respectively to the two largest contact shapes that are guaranteed to contain all other possible solutions to the contact design problem. In practical terms, the proposed characterization of the contact problem enables the systematic exploration of the design space using fully defined representatives of the functionally equivalent class of parts. Furthermore, such exploration may be performed using standard tools from geometric modeling, and without assuming any particular parameterization that necessarily restrict both the design space and possible computational techniques for exploring feasible designs. Because the proposed approach supports the generation of an essentially unlimited space of design solutions for a given contact problem, it is particularly effective at the conceptual design stage. Electronic Publication     

Viscosity of mixtures of fluoroalcohols and water at high pressures

Viscosities of aqueous solutions of 2,2,2,-trifluoroethanol, 2,2,3,3-tetrafluoropropanol and 2,2,3,3,3-pentafluoropropanol have been measured with a falling-body viscometer. Measurements were performed at temperatures from 298 to 323 K and at pressures up to 80 MPa with an estimated uncertainty of ±2%. Viscosities obtained for these mixtures are represented by a simple empirical equation within the experimental uncertainty. The composition dependence of the viscosity is compared with that for mixtures of hydrocarbon alcohols and water.Paper dedicated to Professor Joseph Kestin.     

Effects of fatty acid derivatives on the ignition quality and cold flow of diesel fuel

The biodiesel that is considered as a possible substitute or extender of conventional automotive diesel fuel is commonly composed of fatty acid methyl esters that are prepared from the glycerides in vegetable oils by transesterification with methanol. This form of biodiesel is compatible with diesel fuel but offers no improvement in its ignition quality. This work describes the results of a series of experiments aimed at assessing other common fatty acid derivatives that could provide the desired biofuel component and, at the same time, improve the performance of the fuel. It was found that tertiary fatty amines and amides are significantly more effective than methyl esters in enhancing the ignition quality of the finished diesel fuel without having any negative effect on its cold flow properties.     

糖厂供电系统中的高次谐波污染及治理措施探讨

阐述了糖厂供电系统中谐波污染的严重程度与危害性，并讨论了适用于糖厂的谐波抑制方法。     

三相异步电动机在变频调速中有关问题的探讨

对三相异步电动机在变频调速中的电流、转矩特性、发热原因及解决方法和变频变压调速对电机结构的影响做了探讨,目的是使变频电机与变频器合理匹配,使系统获得最佳的控制效果。     

贴装头设计研究

贴装头是贴片机实现贴装功能的关键部件，是典型的θ-Z机构，贴装轴不仅做旋转运动而且做轴向直线运动。体积小，重量轻，能够高速高精度实现θ-Z运动是贴装头设计的主要目标。采用轴承组合与整体框架结构能够保证贴装结构具有良好的响应特性和高刚度特性。     

合成低碳燃料醇脱水过程中的气相色谱分析

合成低碳燃料醇中含有10％以上的水,脱水后才能作为汽油添加剂。本文对GDX系列和Porapak系列固定相进行了筛选,采用GDX-403对常量水和C_1-C_5醇同时进行分析。用GDX-202或263对水和C_1-C_5醇以及共沸剂环己烷都可进行分析。     

Comparative Absorption of Low Molecular Aroma Compounds into Commonly Used Food Packaging Polymer Films

Five polymer films commonly used in food packages were stored in an aqueous solution of 10 apple aroma compounds. Substances absorbed by the polymers were determined by a supercritical fluid extraction/gas chromatography method. Polypropylene absorbed most aromas, more than 2× amounts absorbed by low density polyethylene. Polyamide and polyester absorbed very small amounts of the aromas. Esters and aldehydes were absorbed much more than alcohols. Molecular size also affected absorption, larger molecules being absorbed to a greater extent than smaller ones. For most materials the absorption equilibrium was reached within a week.     

Refinement concepts formalised in higher order logic

A theory of commands with weakest precondition semantics is formalised using the HOL proof assistant system. The concept of refinement between commands is formalised, a number of refinement rules are proved and it is shown how the formalisation can be used for proving refinements of actual program texts correct.