干旱区盐湖沿岸不同植物群落土壤CO2排放特征

为探究盐湖区不同植物群落土壤CO₂排放速率及影响因素,以新疆达坂城盐湖沿岸小獐毛、鸢尾、芨芨草、黑果枸杞群落和撂荒地土壤为研究对象,在2016年4~12月采用Li-8100A监测了不同植物群落土壤CO₂排放特征,分析了CO₂排放与5（ST5）,10（ST10）,15cm（ST15）土壤温度、含水量、电导率的关系.结果如下：4~12月小獐毛群落土壤CO₂日排放呈单峰曲线,7月土壤CO₂排放速率最高,峰值出现在14：00左右;7月鸢尾、芨芨草、黑果枸杞和撂荒地土壤CO₂排放呈双峰曲线,峰值出现在10：00和14：00~16：00左右,其余月份均呈单峰曲线,峰值出现在12：00~14：00;不同植物群落类型、同一植物类型不同月份土壤CO₂排放存在显著差异（P<0.001）.4~12月芨芨草群落土壤CO₂累积排放量最高（2508.01g/m²）,大于撂荒地（2235.01g/m²）、鸢尾（1903.03g/m²）、黑果枸杞（1690.27g/m²）和小獐毛（550.34g/m²）植物群落处理.小獐毛群落土壤CO₂排放与ST15显著相关（R²=0.739,P<0.05）,且对ST15变化最敏感;鸢尾、芨芨草、黑果枸杞群落和撂荒地处理土壤CO₂排放与ST5相关性较高（R²=0.708~0.821）,对ST10变化响应敏感.小獐毛群落土壤温度敏感系数（Q₁₀）最大值出现在6月（7.97）,鸢尾（21.74）、芨芨草（13.21）、黑果枸杞（18.23）和撂荒地（7.65）处理则出现在11,12月.不同植物群落土壤CO₂排放与含水量相关性较低;一元线性方程（log_eC_f=-0.149EC+0.943）能较好的模拟土壤电导率（EC）与CO₂排放（C_f）的关系.除土壤温度外,盐分也是影响盐湖沿岸土壤碳排放的重要因素.因此,在考虑陆地生态系统碳收支时不能忽略盐湖生态系统,以及盐分对土壤碳过程的影响.     

The “second dividend” and the demographic structure

The demographic structure of a country influences economic activity. The “second dividend” modifies growth. Accordingly, in general equilibrium, the second dividend and the demographic structure are interrelated. This paper aims at assessing empirically the “second dividend” in a dynamic, empirical and intertemporal setting that allows for measuring its impact on growth, its intergenerational redistributive effects, and its interaction with the demographic structure. The paper uses a general equilibrium model with overlapping generations, an energy module and a public finance module that distinguishes between non-ageing-related public spending and a pension regime. Policy scenarios compare the consequences of different scenarios of recycling a carbon tax through lower proportional income taxes rather than higher public lump-sum expenditures. They are computed for two countries with different demographics (France and Germany). Results suggest that the magnitude of the “second dividend” is significantly related with the demographic structure. The more concentrated the demographic structure on cohorts with higher income and saving rate, the stronger the effect on capital supply of the second dividend. The second dividend weighs on the welfare of relatively aged working cohorts. It fosters the wellbeing of young working cohorts and of future generations. The more concentrated the demographic structure on aged working cohorts, the higher the intergenerational redistributive effects of the second dividend.     

臭氧浓度升高对土壤-冬小麦系统CO2排放的影响

通过田间试验,采用静态箱-气相色谱法测定CO2排放通量,研究臭氧(O3)浓度升高对土壤-冬小麦系统CO2排放的影响.结果表明,O3浓度升高对CO2排放的季节变化模式无明显影响.在返青期和拔节孕穗期,O3浓度升高显著降低了土壤-冬小麦系统的CO2排放通量;在抽穗成熟期,O3浓度100 nL·L-1处理对CO2排放通量没有...     

Economic and social effects analysis of mineral development in China and policy implications

Mineral development has contributed greatly to China's economic and social development. Many challenges remain, however, including environmental pollution and resource waste in practice, as well as a dearth of systematic theoretical research. The goal of this study is to analyze the economic and social effects of various mineral developments in China from diversified perspectives, so as to provide the basis for the formulation of China's mineral development policy. The input–output effects, industrial linkage effects and income distribution effects of different mining industries are quantitatively analyzed by adopting basic hypotheses of input–output economics, industrial linkage model and income distribution antitheses based on the latest available official data from China Statistical Yearbook from 2004 to 2010 and the 2007 Input–Output Table of China. The empirical results obtained in this study indicate that all mineral development industries, especially coal mining and washing, and petroleum and natural gas extraction industries, have given a strong impetus to the increase of China's fixed asset investment and GDP. Moreover, they have provided a large number of jobs, thereby alleviating ongoing employment pressure, and they have also played a positive role in promoting China's technology investment. The analysis of industrial linkages demonstrates that mining industries are basic to the national economy and produce a significant impetus to its downstream industries, but create weak pull effects in terms of national economic development. From the perspective of income distribution, mining industries play an important role in increasing China's fiscal revenue and per capital income. Hence, China's mineral development policy should (1) encourage additional investment in technology for exploration and development to insure sufficient supply and expand the input effects; (2) attract additional talent to work in remote regions; (3) optimize the industrial structure and promote the industrial transformation in resource regions; (4) adjust the interest distribution between the central and local governments to enable the local regions to become more self-sufficient; and (5) enhance the legal environment so that companies can more readily undertake their social responsibilities voluntarily.     

20种水溶性有机溶剂对发光菌的毒性效应

以新型淡水发光菌——青海弧菌Q67(Vibrio-qinghaiensis sp.Q67)为检测生物,应用VeritasTM微孔板光度计测定了甲醇等20种常见水溶性有机溶剂对Q67的毒性效应.结果表明,乙腈、甲醇、乙醇、丙酮、乙醚、四氢呋喃和异丙醇7种有机溶剂具有非单调J型剂量-效应关系,其他13种为典型S型剂量-效应关系.分别采用Biphasic、Logit和Weibull等非线性函数进行曲线模拟,利用模拟函数可有效估算有机溶剂的各个效应浓度Ecx值.不同组成和结构的有机溶剂对淡水发光菌的毒性效应不同,官能团相同的直链溶剂含碳数越多毒性越大.     

淡水发光菌对工业废水的生物毒性研究

发光菌作为指示生物用于污染源水体的生物毒性测定具有快速、灵敏、低廉等优点,现已广泛用于环境毒物综合急性毒性测定、筛查、监测及特异毒物监测中.文章利用淡水发光菌Q67对东北地区各行业典型企业的出水口进行急性毒性试验,同时结合化学指标进行了综合评估,试验结果表明:急性毒性试验和化学指标并非在任何水体都相关,但急性毒性试验是化学试验的必要补充.     

基于24Model-AHP的建筑施工高处坠落事故原因研究

为预防建筑施工高处坠落事故,本文采用事故致因“2-4”模型,研究2012-2018年50起高处坠落事故案例,对导致事故的根源原因、根本原因、间接原因和直接原因进行定性分析,并使用SPSS软件分析原因之间的相关性,同时根据事故原因构建递阶层次模型,计算出其权重值并进行排序,从而得到影响事故发生的关键因素。结果表明:安全管理制度和操作规程不健全、员工的安全意识不高和违章操作以及安全防护措施不到位是导致事故发生的主要因素,也是事故预防重点。研究成果对确保施工过程安全,制定相应防范措施有重要意义。     

水利工程建设项目安全生产违规行为分析及监管模式优化

为优化水利工程建设项目安全监管模式、提高安全监管效能,选取山东省2020年重点水利工程质量安全监督报告进行统计分析,梳理出项目法人、代建单位、施工单位、监理单位、设计单位的安全生产违规行为共计1289个,以行为安全“2-4”模型为理论依据,对高频不安全行为产生的原因和规律进行研究。结果显示:水利工程建设项目五方参建单位的高频不安全行为中,安全管理体系程序文件不完善及执行过程不佳的组织不安全行为累计649频次,组织成员安全知识、意识、习惯不佳产生的个人不安全行为累计331频次。据此提出可将监管重点放在对参建单位管理体系的建立与运行上进行组织不安全行为控制,进而控制组织成员个人不安全行为,达到事故预防的目的。     

事故致因“2-4”模型的内涵解析及第6版的研究

为使事故致因“2-4”模型(24Model)在追溯事故原因和制定事故预防对策时取得更好的应用效果,有必要对24Model的内涵进行科学解析。通过文献分析和对比研究,阐述24Model的逻辑结构、原因模块的科学内涵、主要特点。研究结果表明:24Model的主要理论基础,一是HEINRICH、BIRD等提出与改进的多米诺骨牌系列模型,二是REASON提出、SHAPPELL等具体化的瑞士奶酪系列模型和人因分类系统,三是STEWART提出的卓越安全管理模型;静态24Model的逻辑结构以因果关系建立,它属于因果顺序类事故致因模型;静态24Model中事故的直接、间接、根源、根本原因的含义可以从上述3大类事故致因模型、管理体系标准和安全文化的定义中找到根据;动态24Model靠行为演化关系建立逻辑结构,其充分表达自身的系统性、动态性、非线性,并且依靠组织行为即影响行为、个体行为即操作行为,构成一个行为演化系统。     

海洋大气环境下Q235钢表面氯离子沉积量分布规律研究

目的 研究海洋大气环境下氯离子在Q235钢表面的沉积分布规律。方法 使用便携式X射线荧光光谱仪测试Q235钢在海南岛不同地点大气环境暴露后的表面氯离子沉积，然后采用插值算法绘制氯离子在Q235钢表面沉积分布图和海南岛不同地点氯离子在Q235钢表面平均沉积量分布图，并根据氯离子沉积分布图分析氯离子在Q235钢表面的沉积量分布规律。结果 氯离子在Q235钢表面呈不均匀分布特征。在环境暴露试验前6个月，Q235钢表面氯离子含量逐渐增加；暴露6~12个月，Q235钢表面的氯离子含量总体变化不大。从整个海南岛看，内陆地区氯离子在Q235钢表面的沉积量低，而在沿海环岛区域的沉积量高。在海南岛沿海地区，Q235钢表面氯离子沉积量随季风风向的变化而变化。结论 氯离子在Q235钢表面呈不均匀沉积分布，Q235钢表面氯离子沉积量在海南岛不同地点呈“中间低、两边高”的沉积分布规律，内陆地区沉积量低，而沿海环岛区域沉积量高，并且沿海地区的氯离子沉积易受季风风向的影响。