高效液相色谱法测定茶叶和土壤中的氟

建立了测定氟的高效液相色谱法,并通过加入三乙胺使Ｆ－Ｌａ＾３＋－苯素氨羧络合剂体系更稳定。Ｃ１８柱,甲醇－水（１８：８２）作流动相,流速为１ｍｌ／ｍｉｎ,检测波长为５６６ｎｍ,本法线性范围为０．０１０－１．０μｇ／ｍｌ,相关系数为０．９９１,检出限为１ｎｇ／ｍｌ,用于茶叶和土壤样品测定时,相对标准偏差为４．６％－７．３％,加标回收率为９１％￣１０４％。     

广州近地面臭氧浓度特征及气象影响分析

利用2015年广州市近地面逐时臭氧(O_3)观测资料及气象数据,分析了广州地区近地面的O_3浓度时空分布特征及其与气象因子的关系.结果表明:广州地区城郊的O_3浓度高于中心城区;广州地区近地面的O_3浓度超标时间主要出现在4—9月,8月O_3浓度最高,3月O_3浓度最低;O_3浓度日变化呈现"单峰型"分布,早上7:00—8:00出现最低值,15:00达到峰值;O_3浓度与气温呈正相关,当气温高于30℃时,O_3浓度随温度升高增加明显;与相对湿度呈负相关,当相对湿度大于60%时,O_3浓度显著降低;当气压小于1010 hpa时,与气压呈负相关,当气压大于1010 hpa时,与气压呈正相关;当风力为2~3级吹西北偏西至西南偏西风区间时,O_3浓度最高,说明广州偏西部可能存在O_3污染源区;O_3浓度在晴天最高,其次是少云和多云天气,最低是在雨天.总体而言,气温高、日照长、辐射强、气压低、湿度小及2~3级的风力是广州地区近地面产生高浓度O_3的主要气象因素.当广州O_3浓度出现超标时,气温变化范围为25.9~37.4℃,相对湿度变化范围为29%~83%,气压变化范围为989.4~1009.1 h Pa,风速变化范围为0.7~5.8 m·s~(-1),紫外辐射强度日最大1 h均值最小为32.6 W·m~(-2),10:00—14:00均值最小为27.3 W·m~(-2).     

坡面尺度上地貌对α生物多样性的影响

为了解地貌在坡面尺度上对α生物多样性的影响,采用主观采样法在陕北吴起县合家沟流域不同地貌部位进行了样地调查.利用SPSS16.0统计软件先后对各地貌部位物种组成及各物种的重要值、地形因子要素间、地形因子和群落α多样性之间分别做了聚类分析、相关分析和多元回归分析.结果表明:(1)地貌部位相似的群落聚类在一起,说明地形因子是影响物种组成、群落结构、生态系统等的重要因素.(2)海拔和坡位,坡向和坡度,地形指数和海拔、坡位、坡形之间的Pearson 相关系数均大于0.8,双尾显著性检验概率小于0.05.(3)影响α生物多样性指标香农-维纳指数的地形因子按重要性从大到小依次是:坡位、坡向、海拔、坡形、坡度、地形指数,进一步分析得出在黄土高原丘陵沟壑区,沟沿线、光照、土壤水分和养分在影响α生物多样性指标上依次递减.(4)通过多元线形回归检验,得出坡位、坡向、坡形、海拔这四个地形因子与群落α生物多样性关系密切,建立的回归模型显著性检验可信度大,与样本数据的拟合度高.各地形因子数据归一处理后的回归方程为:香农-维纳指数=2.417-0.581×坡形-1.333×坡位+1.449×海拔+0.631×坡向.地形地貌特征在黄土丘陵区表现明显,研究它对生物多样性的影响可为该区植被恢复提供参考,但由于调查样地尺度较小,在应用推广上尚待进一步研究.     

基于管理成熟度的大型水利水电工程环境绩效评价研究

借鉴项目管理成熟度模型的研究方法,构建了大型水利水电工程环境管理成熟度模型,对模型的组成、内容和评价方法进行了定义.结合大型水利水电工程施工过程中的生态环境影响因素分析,建立了大型水利水电工程的环境绩效评价体系,并采用数据包络分析(DEA)动态评估模型进行了环境管理成熟模型评价.案例研究表明,大型水利水电工程环境绩效评价结果能较好的反映出工程施工期间的环境管理成熟度水平,并能反映持续改进方面的环境贡献,研究成果对于改善我国大型水利水电工程建设对生态环境的影响及制定相关政策具有重要意义.     

建筑企业安全文化对安全绩效影响的实证研究

基于安全文化在建筑业安全管理中的重要性越来越突出,因此安全文化对于提高安全绩效,减少建筑业事故发生率的作用日益得到重视。文中进行实证研究,探讨建筑企业安全文化对安全绩效的影响。安全文化的维度为安全制度文化、安全物质文化和安全观念文化,研究结果表明,安全制度文化、安全物质文化和安全观念文化均有助于安全绩效提高,研究结果可在一定程度上促使建筑企业重视并自觉改善安全文化,有助于减少建筑业安全事故发生率,提升安全绩效。     

基于DEA和Malmquist指数的煤矿安全投入效率评价

为了系统的评价煤矿安全投入效率,采用DEA（数据包络分析）方法,选取我国1991~2010年煤矿安全投入产出数据构建DEA模型,其中煤矿安全投入指标为采煤机械化程度、工程技术人员百分比、颁布煤矿安全法规数和行业标准,产出指标为煤矿百万吨死亡率。根据构建的DEA模型对每年的效率进行分析和评价,并提出建议。同时运用Malmquist指数（全要素生产力指数）对煤矿安全投入效率进行分解研究。研究结果表明,从静态上看,我国仅有1993年和2010年当年的煤矿安全投入和产出都达到了最优状态,并且随着煤矿安全投入逐年增加,煤矿安全投入技术效率、纯技术效率、规模效率逐年提升。从动态上看,我国煤矿安全投入Malmquist指数的提高对技术的依赖很明显,无论是技术进步还是技术效率的提高都会相应的提高Malmquist指数。     

美国化学防护服试验与评价用机器人PETMAN研究

美国化学防护服防护因数测试方法-MIST法是评价化学防护服整体防护性能关键技术指标的通行方法,针对现有MIST方法中存在无法对真人采用实际的有毒有害物质对化学防护服进行评价的不足,采用机器人PETMAN替代真人进行MIST试验与评价的需求日益明显。本文针对PETMAN的主要技术构成和相关需求部门提出的要求,详细介绍了研制过程中需要考虑的关键因素,并概述了项目的研究过程以及当前的研究成果。     

Major accident management in the process industry: An expert tool called CESMA for intelligent allocation of prevention investments

A tool (called CESMA) was developed to carry out cost–benefit analyses and cost-effectiveness analyses of prevention investments for avoiding major accidents. A wide variety of parameters necessary to calculate both the costs of the considered preventive measures and the benefits related with the avoidance of accidents were identified in the research. The benefits are determined by estimating the difference in (hypothetical) major accident costs without and with the implementation of a preventive measure. As many relevant costs and benefits as possible were included into the tool, based on literature and expert opinion, in order to be able to deliver an all-embracing cost–benefit analysis and cost-effectiveness analysis to assist in the investment decision process. Because major accidents are related to extremely low frequencies, the tool takes the uncertainty of the unwanted occurrence of a major accident into account through the usage of a so-called ‘disproportion factor’. Compared with existing software, the CESMA tool is innovative by striving for an as-accurate-as-possible picture of costs and benefits of major accident prevention, and taking the uncertainties accompanying disastrous events into consideration. Furthermore, an illustrative example of CESMA is presented in the paper.     

Family–work conflict and job performance: A diary study of boundary conditions and mechanisms

In this study, we used a within‐person daily research paradigm to examine the relationship between daily family–work conflict (FWC) and daily job performance. On the basis of theory on dynamic behavior, we hypothesized that concentration serves as a mechanism through which daily FWC impairs daily job performance. We further predicted that psychological detachment from work during time‐off (i.e., mentally switching off) buffers the negative relationship between daily FWC and daily job performance. Ninety‐five employees completed daily surveys over one workweek. Multilevel modeling results showed that daily FWC was negatively associated with daily job performance and that concentration mediated this relationship. Furthermore, general psychological detachment, but not daily psychological detachment, buffered the negative relationship between daily FWC and daily job performance. The current findings suggest that daily FWC has negative performance implications and that the general level rather than the daily level of psychological detachment from work helps alleviate the negative implications. Copyright © 2013 John Wiley & Sons, Ltd.     

Experimental evidence for the effects of task repetitiveness on mental strain and objective work performance

People frequently have to work in high repetitive jobs. Previous research has focused exclusively on the effects of task repetitiveness on well‐being, while neglecting effects on work performance. In the present study, we aimed to fill this void by conducting two workplace simulations with experimental manipulations of task repetitiveness. Participants worked for about 5 hours at either a computer workstation, compiling computer hardware packages according to customer requests (Experiment 1, N = 160), or at an assembly line, piecing together equipment sets for furniture (Experiment 2, N = 213). Both experiments provide consistent evidence that high repetitiveness has a detrimental effect on well‐being, whereas work performance increases under conditions of high repetitiveness. On a practical level, our study hence shows that high task repetitiveness is a double‐edged sword for both employees and organizations. On a conceptual level, our findings emphasize the necessity to account for both mental strain and work performance when examining the effects of task repetitiveness. Copyright © 2014 John Wiley & Sons, Ltd.