Routing Correlated Data with Fusion Cost in Wireless Sensor Networks

In this paper, we propose a routing algorithm called minimum fusion Steiner tree (MFST) for energy efficient data gathering with aggregation (fusion) in wireless sensor networks. Different from existing schemes, MFST not only optimizes over the data transmission cost, but also incorporates the cost for data fusion, which can be significant for emerging sensor networks with vectorial data and/or security requirements. By employing a randomized algorithm that allows fusion points to be chosen according to the nodes' data amounts, MFST achieves an approximation ratio of 5/4log(k + 1), where k denotes the number of source nodes, to the optimal solution for extremely general system setups, provided that fusion cost and data aggregation are nondecreasing against the total input data. Consequently, in contrast to algorithms that only excel in full or nonaggregation scenarios without considering fusion cost, MFST can thrive in a wide range of applications     

聚合物熔体的非等温平板收缩流动的数值模拟

用有限元法模拟了Carreau流体在4：1平板收缩口模中的非等温挤出流动，采用3节点的三角形单元对速度、压力和温度进行等阶插值，运用特殊的罚函数处理流体的不可压缩条件，解决了压力场的数值振荡问题，并用改进的Newton迭代法对非线性方程进行求解，成功地计算了Carreau流体在平板收缩流动中的速度、压力、粘度以及应力的分布，同时得到温度场的分布，计算的应力分布与实验的结果及Renardy的分析结构相符。     

X射线光刻掩模背面刻蚀过程中的形变仿真

开发了理论模型以验证有限元方法用于X射线光刻掩模刻蚀过程数值仿真的正确性。利用相同的有限元技术，对X射线光刻掩模的背面开窗、Si片刻蚀过程进行数值仿真。结果表明，图形区域的最大平面内形变(IPD)出现在上、下边缘处，最大非平面形变(OPD)出现在左、右边缘处。此外对Si片单载荷步刻蚀和多载荷步刻蚀的仿真进行比较，结果表明图形区域最终的形变量与Si片刻蚀的过程无关。     

浇筑式沥青混凝土心墙型式改进的建议

本文根据浇筑式沥青混凝土主、副心墙材料的性能，分折了沥青混凝土心墙施工或运行中破坏的原因，建议用编织一无纺复合布取代预制块，以避免主、副心墙材料变形性能相差悬残对心墙运行的不利影响，从而发挥浇筑式沥青混凝土心墙的优越性。     

Environmental factors and kinetics of microbial degradation of poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) in an aqueous medium

Environmental factors such as oxygen, temperature, and microbial species may have significant effects on decomposition of biodegradable polymers. A representative biodegradable, thermoplastic polymer, poly(3‐hydroxybutyrate‐co‐hydroxyvalerate) (PHBV), was decomposed in an aqueous medium under controlled laboratory conditions by soil microbes for the intrinsic degradation kinetics and the effects of the environmental factors on polymer biodegradation. The amount of proteins, including the PHBV depolymerases, that attached to the polymer surfaces was quite constant during the period of significant mass loss of the polymer specimens. The microbial polymer degradation followed a zero‐order rate model, so the residual mass fraction of PHBV films declined linearly with time. The mixed aerobic microbial organisms from fertile soil showed a higher activity of polymer degradation than an aerobic PHBV‐producing bacterium and the mixed anaerobes in the same soil. The mixed anaerobic microorganisms from barren soil decomposed the polymer at a slower rate than the anaerobes from fertile soil, and this was attributed to fewer microbial cells in the barren soil instead of the difference in the microbial species. The temperature effect on PHBV degradation can be described with an Arrhenius equation, and the activation energy is around 16 kcal/mol. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 205–213, 2003     

磷酸酯类离子液体在燃油深度脱硫中的应用

研究了3种磷酸酯类离子液体,即1,3-二甲基咪唑磷酸二甲酯盐([MM im]DM P)、1-乙基-3-甲基咪唑磷酸二乙酯盐([EM im]DEP)和1-丁基-3-甲基咪唑磷酸二丁酯盐([BM im]DBP)的制备过程,考察了这3种磷酸酯类离子液体对模型油中3-甲基噻吩、苯并噻吩和二苯并噻吩的脱除效果及磷酸酯类离子液体的电化学再生方法。实验结果表明,这3种磷酸酯类离子液体的脱硫能力强弱顺序为:[EM im]DEP>[BM im]DBP[MM im]DM P;且对二苯并噻吩的脱除效果最好,对苯并噻吩的脱除效果次之,对3-甲基噻吩的脱除效果较差。以[EM im]DEP为萃取剂,油剂质量比为1∶1时,经5次萃取后,二苯并噻吩的脱除率可达到99.5%。利用电解法对[EM im]DEP进行了再生,在5~10V电压下电解10h,[EM im]DEP的脱硫率可以达到新鲜[EM im]DEP的90%以上。     

提高深井硬地层钻井速度技术难点及对策

乌龙1井地层为南方海相沉积,地层古老、岩石硬度大、研磨性强、可钻性差、地层倾角大(最大为80°)井斜难以控制、蹩跳钻严重,制约了该地区深井钻井速度。文章介绍了解决提高钻井速度这一瓶颈问题,从深井优快钻井及其配套技术、硬地层钻进的钻头优选、优化钻井参数、引用新技术、新工艺、新工具等方面进行了探索,钻井速度有了大幅度地提高,对类似井具有一定的借鉴作用。     

油库发油过程中的HSE管理

叙述了石油库在发油过程中的HSE管理；发油过程中的危害识别，包括识别范围和内容；发油过程中风险评价的常用基本方法和常见问题；发油过程中危险源的管理控制，包括建立危险源网络图、加强现场监控和制定应急预案。     

折边锥形封头厚度计算探讨

分析了GB 150-1998《钢制压力容器》中圆筒和折边锥形封头大端的厚度计算公式,认为计算折边锥形封头的厚度时,可只考虑与过渡段相接处的锥壳厚度。     

电磁超声流量计的研制

基于电磁声换能器的原理，研制了一种新型的电磁超声流量计，并讨论提高测量精度的措施。