基于SEM的建筑施工企业KPI安全绩效评价

鉴于建筑施工企业生产安全和服务质量管理以及企业员工综合素质和工作效率的重要性,探讨影响建筑施工企业安全生产的因素,并对建筑施工企业的安全绩效进行全面、客观的评价。采用关键绩效指标(KPI)建立基于人的因素、管理制度、施工设备和环境条件四维度的建筑施工企业安全绩效评价指标体系,研究将结构方程模型理论引入到评价体系中,构建安全绩效评价的结构方程模型(SEM)。总结评价的一般程序,并结合实例,从定量的角度对某建筑施工企业安全绩效进行评价。结果表明,KPI评价体系和SEM评价模型评估得出建筑企业安全绩效影响因素的程度是:人的因素>管理制度>环境条件>施工设备。     

收益视角下我国产业环境压力与经济效益分析

在实现经济效益的同时，兼顾可持续发展已成为推进产业新常态发展的必然选择.本文首先采用多区域投入产出的戈什模型，从行业层面核算了我国各产业2009年的收益侧完全碳排放系数和感应力系数，然后根据2个系数的大小将34个产业部门划分为4大类.实证结果表明：第Ⅰ类行业对经济的推动能力较好，同时对环境产生的负面影响较大.第Ⅱ类行业需要促进行业内整合，提高行业的能源利用率.第Ⅲ类行业属于福利性产业，应当予以保护和支持.Ⅳ类行业具有较高的感应力系数和较低的完全收益侧碳排放系数，兼具行业友好和经济效益，满足当前供给侧结构性改革的内在要求，需要鼓励和发展.     

山西历山山地草甸生物多样性、优势种和土壤因素对群落生产力的影响

自然生态系统生产力同生物多样性、优势种功能性状和土壤性质等多因素紧密关联,因此,受到多变量过程的综合调控。利用结构方程模型研究了山西历山山地草甸物种多样性、功能多样性、优势种功能性状和土壤等多变量因素对群落生产力的影响。结果表明：除了物种多样性外（γ=0.10,P=0.69）,优势种功能性状（γ=0.61,P=0.00）、功能多样性（γ=0.47,P=0.04）和土壤因素（γ=0.34,P=0.02）直接影响群落生产力,并且土壤因素还通过改变优势种功能性状和功能多样性的方式间接影响群落生产力（间接影响系数分别为0.35、0.27）。优势种功能性状是预测群落生产力变化的最佳变量,其次是功能多样性和土壤因素。因此,理解自然生态系统生产力变化应在引入多元方法的前提下,重点考虑优势种功能性状因素。     

温度和氨氮浓度对水体N2O释放的影响

氧化亚氮的释放已经成为了一个全球性的环境问题,水体中N₂O的释放量会随着氮含量的增加而增加.本文通过微宇宙系统的构建,分析氮的转化过程和氮转化基因的变化,并结合结构方程模型分析了温度、氨氮含量对水体N₂O释放的贡献.研究结果发现氨氧化古菌和反硝化细菌丰度均与N₂O释放呈正相关,表明水体中的硝化和反硝化作用都会造成N₂O的释放.氨氮浓度的升高并不直接促进N₂O的释放,而温度和通过硝化作用产生的硝态氮对N₂O的释放有促进作用.此外,硝化速率通过促进亚硝态氮和反硝化菌的丰度而间接地促进N₂O的释放.     

影响振动环境试验的若干关键技术要点解析

从振动试验方案设计、试验方法和步骤、试验设备选择、振动试验控制方法等几个方面对影响振动试验的关键技术进行了详细的解析;并结合结构动力学阐述了振动试验夹具设计的注意要点。     

Dynamic Performance of Horizontal Flexible Anchor Lines During Fall Arrest— A Numerical Method of Simulation

Designing fall arrest systems, which contain horizontal flexible anchor lines is an important technical problem related to the safety of people who work at a height and need horizontal freedom of movement. The article presents a numerical simulation of the dynamic performance of horizontal flexible anchor lines during fall arrest. The model of a 2-component system—a horizontal flexible anchor line and a falling rigid mass, described with a second order non-linear differential equation—is the main element of this method. This method of simulation is realised by a computer program, which allows obtaining the most important data characterising a fall arrest. The article shows laboratory tests used for the verification of this method, which turned out to be a valuable source of information and which can be used for designing fall arrest systems.     

Microecosystem Analysis of the Structure and Functions of Forest Biogeocenoses

The microecosystem approach and an adequate system of quantitative methods have been used to study the relationship between the chorologic changes in the structure and functions of edificator tree stand and other components of the pine (Pinus sylvestris L.) forest cenoecosystems of the Transural and Northern Turgai regions. Significant correlations of the density of pine undergrowth with the litter thickness; of its growth with root competition, stand closeness, and, to a lower degree, photosynthetically active radiation (PAR); and of the numbers of small mammals and groups of soil mesofauna with herbaceous phytomass have been found. The possibility of the synthesis of population-ecological, synecological, and biogeocenological methods has been demonstrated.     

建筑物地震损失估计方法对比分析

合理而准确地确定建筑物的地震损失是当今防震减灾研究的一个主要课题,也是地震保险费率厘定的前提.目前,我国已经在地震发生概率、场地类型、结构性能、财产分布等方面积累了许多震害统计资料.同时,不断应用地震学、抗震工程学和计算方法方面新的研究成果于地震损失的计算,形成了几种常见的损失估计思路和方法.这其中主要包括传统的地震灾害损失风险评估方法、基于动力可靠度的损失分析方法和基于结构性能的损失确定方法.从合理性和适用性的角度,对这3种方法进行了评述和比较,以此看出各种方法的优点和局限性以及分析思路的发展演变过程,并希望从中能够看出今后研究工作的一些方向.     

STRUCTURAL EQUATION MODELING OF DYNAMICS OF NITRATE CONTAMINATION IN GROUND WATER1

ABSTRACT: Most research on the temporal aspect of nitrate pollution in water resources has focused on surface water. Comprehensive studies on the dynamics of nitrate in ground water are lacking, especially on a drainage basin scale and for relatively long periods of time. In this study, structural equation modeling is applied in investigating the influences of climate, hydrology, and nitrogen management in agricultural production on nitrate concentration in the Big Spring Basin, Iowa, over a 10-year period. The study shows that for given hydrogeological settings, nitrogen management practices and climate are the two most important factors that affect nitrate dynamics. The long-term trend of nitrate is closely related to the nitrogen input primarily determined by management practices. The potential effects of nitrogen management, however, are contingent on the variations of climate. The improvements in water quality (reduced nitrate concentration and loads) in relation to improved nitrogen management are often overshadowed by the impact of climate, especially in extremely dry or wet years. The variations of climate and hydrology have much greater impacts on the nitrate dynamics than the changes in nitrogen input. This study reveals significant seasonal variation in the relations between nitrate concentration and influencing factors, which is also closely related to the seasonal variation in climate. Assessment of management practices and resultant water quality should consider the impact of short- and long-term climate dynamics.     

基于多群组SEM的有感领导对群体不安全行为影响研究

为了研究有感领导对建筑施工不同经验工人群体不安全行为的影响,采用问卷调查方法,以群体安全氛围为中介变量,建立了多群组结构方程模型(SEM),并运用AMOS软件分析了有感领导核心四要素(能见度、关系、对工作团体的投入、主动管理)对群体不安全行为的影响及路径系数。结果表明:有感领导对经验缺乏的新工人群体的影响均大于老工人群体;对新工人群体,能见度和主动管理对其不安全行为影响较大,路径系数分别为0.654和0.639;而对老工人群体,关系和对工作团体的投入对其影响较大,路径系数分别为0.577和0.561。因此,在实施有感领导管理时,面对不同经验工人群体,应该因人而宜,以实现更加有效的管理。