北京城市物流业碳排放及驱动因素研究

估算了1998-2012年北京城市物流业的碳排放量,建立了北京城市物流业碳排放影响因素的通径分析模型.结果表明:物流基础设施的建设是该阶段碳排放增长的决定性因素,经济发展水平、以石油为主的能源结构、城镇化是促进碳排放的重要因素,能源效率对碳排放的正向影响较弱,产业结构对碳排放具有负向影响.最后提出了北京城市物流业低碳化发展的对策.     

In–Out Algorithm for assortment planning under a ranking-based consumer choice model

We consider a retailer’s assortment planning problem under a ranking-based consumer choice model. The retailer incurs a fixed carrying cost per product offered, a substitution penalty cost for each customer who does not purchase his first choice, and a penalty cost on lost sales. We develop an effective In–Out Algorithm to identify the optimal solution. The extensive numerical study shows that the algorithm performs well, and is more than 10,000 times faster than enumeration on problems with 20 products.     

论卤盐养生（8）

卤盐（包括食盐）是中国矿物药的重要组成部分。从文化价值、临床应用和情志调摄3个方面诠释了卤盐的养生学意义,并全面、详细地阐述了食盐对中国古代文化的四大贡献、6种盐类的现代临床应用价值以及盐湖旅游的6项要素;列举了160多个盐湖卤水的主要化学成分、矿化度或微量元素;摘录了论述卤盐主治功用的古今文献。本文分期刊出。     

Composting of urban solid residues (USR) by different dispositions

The thermal behavior and non-isothermal kinetics of thermal decomposition of three different kinds of composting of the USR like: stack with drilled PVC tubes (ST), revolved stack (SR) and stack with material of structure (SM), from the usine of composing of Araraquara city, Săo Paulo state, Brazil, within a period of 132 days of composting were studied. Results from TG, DTG and DSC curves obtained on inert atmosphere indicated that the cellulosic fraction present, despite the slow degradation during the composting process, is thermally less stable than other substances originated from that process. Due to that behavior, the cellulosic fraction decomposition could be kinetically evaluated through non-isothermal methods of analysis. The values obtained were: average activation energy, Ea=248, 257 and 259 kJ mol^-1 and pre- exponential factor, logA=21.4, 22.5, 22.7 min^-1, to the ST, SR and SM, respectively. From Ea and logA values and DSC curves, Málek procedure could be applied, suggesting that the SB (Šesták-Berggren) kinetic model is the appropriated one to the first thermal decomposition step. This revised version was published online in July 2006 with corrections to the Cover Date.     

Volatile organic compounds in an urban environment: a comparison among Belgium,Vietnam and Ethiopia

The effects of urban and indoor air pollution on human health are a major environmental concern for all, but not much has been researched in the developing world. Specifically, quantitative data on the occurrence of volatile organic compounds (VOCs) – main contributors to air pollution – in Asia and Africa are scarce compared to the availability of data in the developed world. This paper presents one of the first studies focusing on the analysis and occurrence of VOCs in Vietnam and Ethiopia, which constitutes part of the novelty of this work. A spectrum of 34 VOCs was measured at eight different urban sites in Ghent (Belgium), Hanoi (Vietnam), Jimma and Addis Ababa (Ethiopia) during three sampling campaigns from September 2008 to September 2010. Sampling was done in an active way by means of sorbent tubes filled with Tenax TA. The analysis was done by TD-GC-MS using internal standard calibration. Data were interpreted and compared in terms of (i) individual, subgroup and total VOCs concentration (TVOCs), (ii) indoor-to-outdoor (I/O) concentration ratios, (iii) source identification by diagnostic ratio and/or correlation coefficients, and (iv) ozone formation potential (OFP) at outdoor sites based on up-to-date maximum incremental reactivity (MIR). I/O concentration ratios varied between 0.2 and 30, with big differences noticed with respect to the type of VOC(s) considered and the type of outdoor sampling location. The highest TVOC concentrations were measured in street samples with maximum values of 54?µg/m³ in Ghent, 507?µg/m³ in Hanoi and 318?µg/m³ in Addis Ababa illustrating the large difference in ambient air quality levels. This is also reflected in the arithmetic mean OFP values (µg/m³) of 82, 1308 and 596 in Ghent, Hanoi and Addis Ababa, respectively. Results of this study could be helpful to support formulation of national policy with regard to ambient air quality.     

啦啦操阿拉C杠难度动作的力学原理及其应用

阿拉C杠属于啦啦操转体类难度,在啦啦操成套动作中有着至关重要的地位。为探明阿拉C杠的力学原理,为其训练方法和评价标准提供科学依据,本文以机器人学理论为基础建立了阿拉C杠运动过程的人体模型,并对运动过程进行了运动规划和运动学仿真。然后应用拉格朗日方程建立了阿拉C杠动作的动力学模型,针对一种理想的运动状态对阿拉C杠运动过程中人体各主要关节的驱动力进行了分析。最后,根据动力学仿真结果对比了双臂开合、单臂开合和大小T三种手部动作对身体各关节驱动力的影响。分析结果表明,动力腿是阿拉C杠动作的主要动力来源,动力腿髋关节的驱动力不受手部动作的影响。在双臂开合、单臂开合和大小T三种手部动作中,大小T需要的关节驱动力最小。本文为阿拉C杠的训练与评价提供了理论依据,可供练习者在训练过程中参考使用。