面向冲击负荷的新型电能表关键技术研究

非线性冲击负荷会对计量点的电流、电压及频率产生较大影响,会引起较严重的电能计量误差。在分析非线性冲击负荷对计量误差影响的基础上,建立了冲击负荷模型,给出较为精确的冲击负荷仿真方法,据此给出了新型冲击负荷电能表的设计方案和设计原理,设计了电压、电流高速AD采样电路,给出了零磁通电流互感器设计方法,提出了一种冲击负荷计量方法及算法思路,给出了基于IIR低通滤波器的冲击负荷滤波算法及具体参数,设计出新型冲击负荷电能表。在冲击负荷模型的基础上,设计了冲击负荷典型实验环境,分别在暂态冲击负荷、短时冲击负荷、长时冲击负荷等条件下对待测冲击负荷电能表进行实验,实验结果表明,所设计的新型冲击负荷电能表能准确计量冲击负荷电能。     

弹性体/刚性粒子协同增韧PVC研究

研究了不同组成的聚氯乙烯(PVC)树脂/耐热改性剂/(甲基丙烯酸甲酯/丁二烯/苯乙烯)共聚物(MBS)复合体系的力学性能和耐热性能,用扫描电子显微镜分析共混材料的冲击断面微观形态,用动态热机械分析仪测定其动态热力学性能.结果表明,在PVC中添加8份MBS、10份耐热改性剂时共混材料的力学性能和耐热性能达到一个均衡值,冲击断面出现了明显的"须根"现象,PVC材料由脆性断裂转变为韧性断裂,二者协同作用既提高了共混材料的韧性,又改善了其耐热性能.     

一种基于RTO的业务排序算法

业务影响分析是业务连续性计划中较为关键的一步,其最终目标是对企业中业务的重要性进行排序。文中的目的是提出一种企业在进行灾难恢复时,各个业务过程之间恢复优先顺序的排序算法。该算法在设计时基于RTO进行排序,并考虑了业务之间的相互依赖关系对恢复顺序的影响。通过实验显示了该算法的合理性：使用该算法可以更好地实施业务影响分析,缩短分析时间,从而提高整个业务连续性实施过程的效率。     

Trace metal concentrations in the North-western Mediterranean atmospheric aerosol between 1986 and 2008: Seasonal patterns and decadal trends

Climatic and anthropogenic changes are able to engender modifications in the aerosol composition at different geographical and temporal scales. The present study addresses this question for the trace metal concentrations (TM = Al, Fe, Mn, Co, Ni, Cu, Pb, Cd and Zn) of aerosol from the North-western Mediterranean coast of France (Cap Ferrat, nearby Nice) between 1986 and 2008. From seasonal variations (2006-08) and decadal trends (1986-2008) of TM concentrations, three groups of elements can be distinguished. They consist of different aerosol sources: crustal-derived elements (Al, Fe, Mn and Co), trace metals of anthropogenic origin (Pb, Cd and Zn) and a third, intermediate, group of trace metals that presented both anthropogenic and natural/crustal influences (Ni and Cu). Reproducible seasonal patterns were observed for crustal and intermediate elements with highest concentrations between May and November, while anthropogenic trace metals did not show a pronounced seasonal cycle. Nevertheless, highest concentrations of anthropogenic trace metals occurred mostly in autumn/winter. Aerosol concentrations of anthropogenic TMs decreased remarkably over the last two decades, while crustal trace metals did not show any evolution. Nickel and copper aerosol concentrations remained constant, as well. Lead concentrations decreased from 1986 (29.34 ng m^− 3) to 2008 (3.33 ng m^− 3), overall by 90%. Cadmium and zinc aerosol concentrations decreased by 66 and 54%, respectively, between 1998 and 2006-08, from 0.27 to 0.09 ng m^− 3 and from 23.9 to 10.9 ng m^− 3, respectively. These findings demonstrate the response of the atmospheric environment to the implementation of antipollution policies. Possible changes of trace metal emissions sources and local influences are discussed.     

An LCA-based environmental impact assessment model for construction processes

A quantitative assessment of the environmental impact of construction activities can help decision-makers identify major environmental impact factors and make environmentally friendly construction plans in the early stages of construction. This paper presents an integrated life cycle environmental impact assessment model that is applicable to construction phase studies, where impact factors are examined according to two aspects of a typical construction process: construction equipment and ancillary materials. Environmental impacts are categorized into three safeguard subjects: ecosystems, natural resources and human health. A disability adjusted life year (DALY) model for assessing human health damage due to construction dust is developed. In addition, the environmental impact of earthwork construction is assessed as a case study to demonstrate the application of the proposed model. Results indicate that the proposed model can effectively quantify the environmental impacts of construction processes, and can potentially be used as a tool for contractors to select environmentally friendly construction plans.     

Preparation and characterization of polypropylene homocomposites: Exploiting polymorphism of PP homopolymer

In this study, the properties of polypropylene (PP) homocomposites, prepared by film‐stacking followed by hot pressing, were investigated. Alpha‐ and beta‐PP served as matrices, whereas highly oriented PP tapes of the alpha form acted as reinforcement in the homocomposites. Tapes with different draw ratios (DR = 6–12) have been produced and characterized by mechanical and wide‐angle X‐ray scattering measurements. Tapes with a DR = 8 were incorporated in a cross‐ply (CP) manner in the corresponding homocomposite laminates. Specimens were subjected to static (tensile, flexural) and dynamic (instrumented falling weight impact, IFWI) tests. The thermal and thermomechanical properties of the PP tapes and homocomposites were studied by differential scanning calorimetry and dynamic mechanical thermal analysis. The homocomposite morphology was probed by polarized light microscopy, which gave evidence of transcrystalline layer at the interface between tape and matrix. The storage modulus of the CP homocomposites was improved prominently by the tape reinforcement. In static tensile tests, the homocomposites exhibited much higher stiffness and strength when compared with the neat PP specimens. However, this was accompanied with a marked reduction in the ultimate elongation. The IFWI tests showed that both alpha‐ and the beta‐PP failed in macroscopically brittle manner, whereas the corresponding homocomposites failed in semiductile way. The homocomposite laminates prepared with beta‐PP matrix exhibited higher resistance to penetration than those with alpha‐PP. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

水泥行业建设项目环境影响评价应重视矿山开采环境影响

我国是世界上第一水泥生产大国,而且水泥投资过热。按照国家的环境影响评价的法律要求,水泥建设项目必须进行环境影响评价。水泥建设项目表现的污染主要有工业污染和生态环境影响两个方面。在以往的水泥建设项目中,只重视水泥生产厂区的污染物排放和环境影响,轻视甚至忽略矿山开采对生态环境的破坏和影响,造成对水泥建设项目环境影响评价工作的不完善。随着《环境影响评价技术导则-非污染生态影响》的颁布,在水泥行业建设项目环境影响评价中要重视矿山开采的环境影响评价。文章重点论述在水泥建设项目中矿山开采环境影响评价应注意的问题。     

超临界流体SAS法制备HMX基传爆药及其表征

采用超临界流体SA S法,通过引入钝化包覆剂FPM2602对超细HM X主体炸药的粒子表面均匀包覆,最终获得超细HM X基传爆药。利用扫描电子显微镜(SEM)表征了原料和超细HM X基传爆药的表面形貌。测定了其撞击感度、冲击波感度及起爆感度,并与J0-9C(I型)传爆药进行对比。结果表明,超细HM X基传爆药的表面形貌得到了明显改善;与J0-9C(I型)传爆药相比,其H50值升高了17.1 cm,冲击波隔板厚度(xR)减小了2.2mm,起爆性能得到了显著提高。     

湿法磷酸生产精细磷酸一铵结晶改善剂研究

研究了氨中和法净化湿法磷酸的效果,筛选出了适宜的结晶改善剂。研究结果表明:在中和终点pH为4.0时,铝离子、铁离子、氟离子的净化率均达到98%以上,镁离子的净化率为50%,生成的磷酸一铵结晶细小,呈针状。氟离子作为结晶改善剂,能明显消除铝离子对于结晶的影响,但对于铁离子的效果不明显;螯合结晶改善剂Chet-a可以基本消除铁离子的影响。采用氟离子和Chet-a联合作用,可以基本消除杂质对结晶的影响,改善晶形,产品磷酸一铵长径比达3.5:1,可以生产出合格的产品。     

不同安装基座下冲击信号的冲击响应谱研究

在利用冲击传感器进行冲击测试过程中通常会用到安装基座,不同材料的安装基座会对冲击传感器的测试结果产生不同的影响,对某型号冲击传感器在不同材料的安装基座下进行冲击测试,并对冲击结果进行冲击响应谱分析,利用冲击响应谱分析结果来说明高分子材料安装基座和铝合金材料安装基座分别对冲击测试产生的影响,分析结果表明高分子材料安装基座具有良好的应力传递特性,冲击信号失真小,但是冲击信号衰减较大;而铝合金材料安装基座频率传递特性好,具有良好的频率响应特性,但是冲击信号有较大失真。