我国汽油柴油产品质量升级问题探讨

介绍了国外汽油柴油产品质量现状．对国内外车用燃料标准及炼油装置结构进行了对比分析，指出降低硫含量是提高国产汽油柴油产品质量的关键。为了做好国产汽油柴油产品质量升级工作，提出加大炼油装置结构调整力度、发挥现有催化裂化和重整装置能力的建议。     

提问马岩松

文章记录了《时代建筑》对青年建筑师马岩松的一次书面采访。被访者谈及对数字建筑的理解、对红螺湖会所的建造控制、对形式的回应,以及建筑师通过媒体影响社会的潜力等问题。通过若干案例,解析了建筑师和他的MAD事务所对社会问题的敏感回应以及与资本、决策层交流的策略。     

水平冷表面上结霜发生随机性研究

水蒸气在冷壁面上的结霜是制冷、低温领域普遍存在的问题。过饱和的水蒸气有两种相变途径，一种是气液固相变；一种是直接气固相变。气液固相变经历气液相变和液固相变两个阶段，实验研究表明其发生具有随机性。在前人实验研究的基础上，从理论上给出了液珠半径随时间的增长规律，并进一步得到了冷壁面自然对流情况下结霜发生概率随时间的变化关系式。     

牛磺酸对顺铂导致培养的原代兔肾小管细胞损伤的保护作用

目的：研究牛磺酸对顺铂导致培养的原代兔肾近端小管细胞(PTC)损伤的保护作用。方法：在体外建立原代兔肾近端小管细胞培养。采用溴乙锭荧光法测量DNA链间交联和Fur-2／AM测量细胞内游离钙离子浓度。首先将牛磺酸(0．1，1，10g．L^-1)与PTC保温24小时,然后，加入顺铂使其终浓度达到26μmol.L^-1,再继续保温24小时。顺铂损伤组同样培养48小时。前24小时不加入牛磺酸和顺铂,后24小时加入顺铂使其终浓度为26μmol.L^-1。对照组不加入牛磺酸和顺铂，同样培养48小时。结果：顺铂导致损伤组形成DNA链间交联和细胞内游离钙离子浓度升高．牛磺酸1．10g．L^-1可明显降低DNA链间交联和细胞内游离钙离子浓度。结论：牛磺酸可保护顺铂对PTC的损伤。     

Finite element buckling analysis of rotationally periodic laminated composite shells

A finite element (FE) buckling analysis of rotationally periodic laminated composite shells is performed in this paper. Because the buckling mode of such structures is characterized as rotationally periodic, a corresponding FE buckling analysis scheme is proposed to reduce the computational expenses. Moreover, a new kind of relative degrees‐of‐freedom element is developed, which can be connected to other solid elements with ease and can yield satisfactory results with a relatively coarse FE mesh. Numerical results of two laminated cylindrical shells subjected to lateral pressure are compared with theoretical ones. The good agreement of them shows the validity of this new computational strategy. Finally, a practical structure is analysed to demonstrate the advantage of this method. Copyright © 2001 John Wiley & Sons, Ltd.     

改进型A*算法的可重构机器人路径规划研究

路径规划是保证可重构机器人快速完成任务的关键技术之一。为提高可重构机器人的行驶效率，缩短行驶路径，首先，提出一种基于Bresenham直线算法思想的改进型A*路径规划算法，实现可重构机器人路径点数消减、拐点消除，提高路径平滑度。在此基础上，考虑可重构机器人本身体积以及机器人可重构的特性，建立可重构机器人构型库，讨论了可重构机器人体积与周围障碍物的关系，减少机器人行走过程中与障碍物的碰撞几率。利用MATLAB仿真平台对改进型A*路径规划算法进行仿真实验，验证了算法的有效性，可应用于复杂环境的机器人路径规划；分析了机器人重构后路径规划问题，利用可重构特性可缩短机器人运行路程，体现了可重构机器人的优越性。     

软件产品易用性测试及回归测试方法探究

基于不同的立场，存在着两种不同的测试目的。从用户的角度出发，希望通过软件测试暴露软件中隐藏的错误和缺陷，以考虑是否可以接受该产品；而从软件开发者的角度出发，则希望测试成为表明软件产品中不存在错误的过程，验证该软件已正确地实现了用户的需求，实际上，软件有些缺陷和错误只有在特定的环境下才可能暴露出来。软件测试的目的就是以最少的时间和人力发现软件中潜在的各种缺陷和错误，本文就软件产品的易用性测试方法及回归测试方法做一论述。     

Partial recovery of quantum entanglement

Suppose Alice and Bob try to transform an entangled state shared between them into another one by local operations and classical communications. Then in general a certain amount of entanglement contained in the initial state will decrease in the process of transformation. However, an interesting phenomenon called partial entanglement recovery shows that it is possible to recover some amount of entanglement by adding another entangled state and transforming the two entangled states collectively. In this paper, we are mainly concerned with the feasibility of partial entanglement recovery. The basic problem we address is whether a given state is useful in recovering entanglement lost in a specified transformation. In the case where the source and target states of the original transformation satisfy the strict majorization relation, a necessary and sufficient condition for partial entanglement recovery is obtained. For the general case we give two sufficient conditions. We also give an efficient algorithm for the feasibility of partial entanglement recovery in polynomial time. As applications, we establish some interesting connections between partial entanglement recovery and the generation of maximally entangled states, quantum catalysis, mutual catalysis, and multiple-copy entanglement transformation.     

利用废钢结硬质合金制备杂多酸

探讨了利用稀硫酸和浓硝酸分步处理废TLMW50钢结硬质合金,结合焙烧、浸取、结晶、水解、还原等方法,分离金属成分,制备12-磷钨酸、12-磷钼酸、绿矾、硫酸铬等化学试剂的生产工艺。     

Service overlay networks: SLAs, QoS, and bandwidth provisioning

We advocate the notion of service overlay network (SON) as an effective means to address some of the issues, in particular, end-to-end quality of service (QoS), plaguing the current Internet, and to facilitate the creation and deployment of value-added Internet services such as VoIP, Video-on-Demand, and other emerging QoS-sensitive services. The SON purchases bandwidth with certain QoS guarantees from the individual network domains via bilateral service level agreement (SLA) to build a logical end-to-end service delivery infrastructure on top of the existing data transport networks. Via a service contract, users directly pay the SON for using the value-added services provided by the SON. In this paper, we study the bandwidth provisioning problem for a SON which buys bandwidth from the underlying network domains to provide end-to-end value-added QoS sensitive services such as VoIP and Video-on-Demand. A key problem in the SON deployment is the problem of bandwidth provisioning, which is critical to cost recovery in deploying and operating the value-added services over the SON. The paper is devoted to the study of this problem. We formulate the bandwidth provisioning problem mathematically, taking various factors such as SLA, service QoS, traffic demand distributions, and bandwidth costs. Analytical models and approximate solutions are developed for both static and dynamic bandwidth provisioning. Numerical studies are also performed to illustrate the properties of the proposed solutions and demonstrate the effect of traffic demand distributions and bandwidth costs on SON bandwidth provisioning.