Use of Warranties on Highway Projects: A Real Option Perspective

Since the introduction of warranty provisions in federal highway jobs, more and more state departments of transportation (DOTs) have considered the use of such provisions to protect their initial investment. This paper describes the pros and cons of warranty contracting in highway construction based on a survey of warranty practices in the United States. In particular, the need for state DOTs to buy a warranty for a well-built project is questioned. As an alternative, this paper introduces the warranty option, which gives the DOT the right to buy a warranty only if it becomes necessary at the end of construction. This option is exercised if the performance on site warrants it. This paper describes the mechanics of the warranty option and its advantages over the conventional warranty. A bid evaluation model is also developed for the warranty option approach.     

环氧乙烷合成乙二醇的研究进展

介绍了环氧乙烷合成乙二醇的主要生产方法，包括以壳牌、联碳化学公司以及Halcon—SD公司为代表的环氧乙烷直接水合法，环氧乙烷催化水合法和碳酸乙烯酯法，后两种乙二醇生产方法是目前国内外研究开发的热点。催化剂体系是催化水合法工艺的关键，重点介绍了国内外各主要公司对催化剂体系的研究进展及使用效果；碳酸乙烯酯法分为乙二醇和碳酸二甲酯联产法以及碳酸乙烯酯水解法，详细介绍了国内外各主要公司对该技术的研究进展，包括工艺流程、催化剂体系等方面。将3种乙二醇生产方法进行技术经济比较，结果表明，催化水合法和碳酸乙烯酯法在原料消耗和能耗方面占优势。并对我国乙二醇生产工艺技术提出建议。     

马克法输铝管用胶结剂的研制及应用

用粘土熟料、软质粘土及复合结合剂研制的胶结剂,用于马克法铸钢输铝管系统的胶结,其使用性能和使用寿命达到或超过了进口胶结剂的水平。     

大港油田CNG加气站技术特点

天然气作为我国最主要能源之一，其应用领域在不断地扩展。由于天然气受管网敷设的限制。在压缩、储运等方面的技术也引起了众多企业的重视，并成为一些企业发展的战略目标。2004年大港油田依靠地域和气源的优势，建成了天津市首座CNG加气站。经过一年来的生产运行，显现出较好的经济效益和良好的发展前景。从环保性、安全性和经济性等方面阐述了CNG技术特点和发展的优势，对大港油田已建CNG加气站的主要设备、工艺流程、技术特点以及市场发展前景进行了较详尽的阐述。     

一种数字语音通信系统的DSP实现

介绍了一种甚低频低码率数字通信系统的实现方案，该方案中的软件采用混合编程的方法，硬件则用DSP实现，文章给出了整个系统的DSP软硬件调试方法，并通过调试结果表明该方案具有很好的可行性和实时性。     

自治Agents的面向服务的协商模型

提出了一个基于自治Agents的面向服务的协商模型。模型主要包括两大模块：首先定义了一系列的战略和战术过程，使得Agents可以产生初始建议，评价对方的建议，以及在此基础上做出反建议；其次，定义了两个层次的Agent通信机制。二者相辅相成，实现了Agents间合作的动态形成和随机协调，使得Agents可以承担因环境的不确定性而需动态协作的复杂任务。     

Effect of polymerization conditions on o‐phenylenediamine and o‐phenetidine oxidative copolymers

A series of new o‐phenylenediamine (OPD)/o‐phenetidine (PHT) copolymers with partly phenazine‐like structures has been successfully synthesized at three polymerization temperatures by chemically oxidative polymerization in four different polymerization media. The molecular structures and properties of the resulting OPD/PHT polymers were investigated by IR, UV–vis and high‐resolution ¹H NMR spectroscopies, and DSC, in order to ascertain the effect of reaction temperature, comonomer ratio and acid medium. The copolymerization mechanism of OPD with PHT monomers has been proposed. It is found that the statistical OPD/PHT copolymer obtained at a temperature of 118 °C has a higher degree of polymerization than that obtained at 12–17 °C. The OPD content in the copolymers calculated from NMR spectroscopic analysis is higher than that in the feed OPD content, whereas the OPD content calculated from element analysis is slightly lower than the feed OPD content. It can be predicted that denitrogenation takes place in the OPD units during the polymerization process at OPD/PHT molar ratios of 90/10 and 100/0. These OPD/PHT copolymers exhibit a much better solubility than the OPD homopolymer, hence suggesting an incorporation of PHT units into the phenazine structure of the homopolymer. The thermal behavior of the copolymers was also studied. Copyright © 2004 Society of Chemical Industry     

锰锌铁氧体纳米粉体的液相制备及磁性能

以δ-FeOOH为前驱体,用氨水调节溶液的pH值,分别采用(1)90℃水浴加热动态转化、(2)沸腾回流动态转化,(3)90℃静态转化及(4)200℃水热法四种方法合成了锰锌铁氧体纳米粉体.采用X射线衍射仪(XRD),透射电子显微镜(TEM)、振动样品磁强计(VSM)和X射线荧光光谱仪(XRF)等方法对粉体进行了表征,对四种液相法制备的锰锌铁氧体纳米粉体的结构和性能等进行了对比和分析.结果表明,四种方法中沸腾回流相转化法得到的产物具有磁性能较好、形状较规则、粒径可控等优点.     

DataSocket技术在远程测试中的研究与应用

本文介绍了一种实时数据传输技术-DataSocket,并给出了具体实例说明了如何将利用DataSocket技术来实现远程测试。     

"JDS-音频化渣微机综合检测系统"的应用与效果

简要介绍“JDS-音频化渣微机综合检测系统”的工作原理和应用效果，证明使用该装置是提高炼钢操作水平的一条较好途径。