区域差异下农业用水效率对农业用水量的影响

基于全国30个省份1998~2015年面板数据,采用Super-SBM模型测算农业用水效率,并在观察农业用水量、农业用水效率动静态演进特征的基础上,利用门槛面板回归模型探究农业用水效率对农业用水量的影响。结果表明,全国农业用水量和农业用水效率均呈阶段性下降。农业用水效率对降低农业用水量具有显著的门槛效应,提高农业用水效率是降低农业用水量的有效途径;东部农业用水效率促进农业用水量下降,但须警惕"回弹效应";中部农业用水效率抑制农业用水量增长,且作用逐渐增强;西部农业用水效率提高能够快速降低农业用水量,但作用逐渐减弱。另外,提升农民受教育水平、增加绿水足迹、扩大农业劳动人口能够降低农业用水量,而丰富的水资源禀赋促进农业用水量增加。     

基于AHP的世界一流能源化工公司HSE绩效综合对比研究

深入分析与综合对比壳牌、埃克森美孚、BP、雪佛龙、道达尔、康菲等6家世界一流能源化工公司近10年HSE绩效数据,利用层次分析法(AHP)构建综合对比分析模型.确定准则层包含的死亡人数、损失工时事故率、可记录事件率等6个二级要素,利用各公司近年HSE绩效数据,定义HSE绩效控制能力指数,确定方案层对准则层的判断矩阵,通过计算得到各公司在HSE绩效综合对比排序,为能源化工企业HSE管理提供参照.     

Forecasting of dissolved oxygen in the Guanting reservoir using an optimized NGBM (1,1) model

An optimized nonlinear grey Bernoulli model was proposed by using a particle swarm optimization algorithm to solve the parameter optimization problem. In addition, each item in the first-order accumulated generating sequence was set in turn as an initial condition to determine which alternative would yield the highest forecasting accuracy. To test the forecasting performance, the optimized models with different initial conditions were then used to simulate dissolved oxygen concentrations in the Guanting reservoir inlet and outlet (China). The empirical results show that the optimized model can remarkably improve forecasting accuracy, and the particle swarm optimization technique is a good tool to solve parameter optimization problems. What's more, the optimized model with an initial condition that performs well in in-sample simulation may not do as well as in out-of-sample forecasting.     

Forecasting of dissolved oxygen in the Guanting reservoir using an optimized NGBM (1,1) model

An optimized nonlinear grey Bernoulli model was proposed by using a particle swarm optimization algorithm to solve the parameter optimization problem. In addition, each item in the first-order accumulated generating sequence was set in turn as an initial condition to determine which alternative would yield the highest forecasting accuracy. To test the forecasting performance, the optimized models with different initial conditions were then used to simulate dissolved oxygen concentrations in the Guanting reservoir inlet and outlet (China). The empirical results show that the optimized model can remarkably improve forecasting accuracy, and the particle swarm optimization technique is a good tool to solve parameter optimization problems. What's more, the optimized model with an initial condition that performs well in in-sample simulation may not do as well as in out-of-sample forecasting.     

宜昌市水环境质量红线划分与空间管控研究

在宜昌市水环境质量红线划分中,对饮用水源保护区划分、水环境功能区划分和流域控制单元划分给予评估,分析在城市水环境质量红线划分上的可取之处,在自然社会综合系统框架下创造性的提出了适应宜昌城市环境总体规划中水环境质量红线划分的原则、技术方法和分级管控措施,提出的原则与适宜的管控措施为宜昌市水环境质量改善、环境公共服务实现与生态城市建设提供了支持,丰富并实践了生态保护红线体系.     

Effect of plant harvest on methane emission from two constructed wetlands designed for the treatment of wastewater

The emission of methane from two constructed wetlands [a free water surface flow system (FWS) and a subsurface flow system (SF)], constructed for the treatment of waste water, was evaluated at different sites inhabited by reeds (Phragmites communis), to test the effects of plant harvest. High methane emission was recorded immediately after harvesting in both wetlands. Several days after harvesting, the emission decreased in the FWS but remained high in the SF. The variation was significantly influenced by temperature, with lower emission and higher dissolved CH(4) in water occurring at lower temperatures. Both the emission and concentration of dissolved CH(4) were also influenced significantly by water quality, wetland design, level of stalk butt left above the water level, etc. The methane flux was explained on the basis of rizhospheric methanogenic and methanotrophic microbial populations. FISH analysis indicated the presence of Type A and Type B methanotrophs in both wetlands, and the methane flux was directly influenced by the quantitative variation in methanogenic and methanotrophic bacteria in both wetlands.     

某炼化企业催化汽油吸附脱硫装置职业病危害控制效果评价

通过资料调研、现场调查与检测，将获取的资料与法律、法规和标准要求相比较，对某炼化企业催化汽油吸附脱硫装置进行了职业病危害控制效果评价。     

Soil ecotoxicity assessment using cadmium sensitive plants

Four crop plant species (sweet corn, Zea may; wheat, Triticum aestivum; cucumber, Cucumis sativus; and sorghum, Sorghum bicolor) were tested to assess an ecotoxicity in cadmium-amended soils. The measurement endpoints used were seed germination and seedling growth (shoot and root). The presence of cadmium decreased the seedling growth. The medium effective concentration values (EC50) for shoot or root growth were calculated by the Trimmed Spearman-Karber method. Due to the greater accumulation of Cd to the roots, root growth was a more sensitive endpoint than shoot growth. Bioavailability and transport of Cd within plant were related to concentration and species. The ratio of bioaccumulation factor (BAF) in the shoots to the roots indicated high immobilization of Cd in the roots. Seed germination was insensitive to Cd toxicity, and is not recommended for a suitable assay. Among the test plants and test endpoints, root growth of sorghum and cucumber appears to be a good protocol to assess ecotoxicity of soils contaminated by Cd.     

自导式解说系统设计要素研究--以邓小平故居景区为例

以邓小平故居自导式解说系统的实际设计、制作为例,重点研究了自导式解说系统在设计中应当把握的四大要素,并对这四大设计要素在设计过程中的相互关系进行了理论研究和实例分析,指出这四大要素是旅游区设计出高水平、高质量的自导式解说系统的关键核心，从而使自导式解说系统成为提升旅游区整体形象的重要组成部分.     

因子分析法在江安河地表水水质评价中的应用

因子分析法是主成份分析方法的推广和深化，是把原来多个变量化为少数几个综合指标的一种统计方法。本文通过该法对江安河四川大学双流校区段水质进行了评价，结果表明，该水体受到了不同程度的有机物污染，其中非离子氨、阴离子洗涤剂、化学耗氧量，溶解氧所占的负荷最大。