青铜峡灌区水土资源平衡分析的探讨

本文根据青铜峡灌区四水转化的特点和灌区规划的要求，提出灌区节水改造规划的水土资源平衡应进行水资源的3个平衡分析，即水资源供需平衡分析，引水、耗水与排水平衡分析，水资源耗水平衡分析.水资源的3个平衡分析的目标与内容不同，但科学基础与依据都是灌区的四水转化关系.     

Estimating the Impact of Transgenic Bt Cotton on West and Central Africa: A General Equilibrium Approach

West and Central Africa (WCA)’s cotton sector is experiencing rising production costs and lower yields, reversing decades of growth. Declining input use, soil fertility and inefficient chemical pest controls are contributing factors. We evaluate the potential impact of Bt cotton on WCA using a multiregion general equilibrium model and multicountry estimates of Bt-induced productivity. We find that Bt cotton raises growers’ returns, land value and welfare. Released labor from cotton is shifted to food crops hence reducing labor shortage constraints. Overall, results indicate that potential gross benefits from Bt cotton are substantial for WCA cotton sector, and that the economic costs of nonadoption are equally significant.     

宁夏黄河段水库泥沙淤积对大坝防渗与结构安全影响研究

以宁夏黄河段某水库为例,在对其泥沙淤积原因进行总结分析的基础上,对其淤积情况下大坝渗流分析、结构分析及抗震安全分析进行了有限元计算。研究表明:(1)泥沙淤积情况下大坝渗漏量减小,大坝稳定性增强,抗震安全系数增大;(2)泥沙淤积导致水库有效库容减小,水库建筑物无法正常工作,水库下游生活用水和农业用水无法满足,应采取必要的清淤措施。     

Multiple responses analysis and modeling of Fenton process for treatment of high strength landfill leachate

Landfill leachate is one of the most recalcitrant wastes for biotreatment and can be considered a potential source of contamination to surface and groundwater ecosystems. In the present study, Fenton oxidation was employed for degradation of stabilized landfill leachate. Response surface methodology was applied to analyze, model and optimize the process parameters, i.e. pH and reaction time as well as the initial concentrations of hydrogen peroxide and ferrous ion. Analysis of variance showed that good coefficients of determination were obtained (R2 > 0.99), thus ensuring satisfactory agreement of the second-order regression model with the experimental data. The results indicated that, pH and its quadratic effects were the main factors influencing Fenton oxidation. Furthermore, antagonistic effects between pH and other variables were observed. The optimum H2O2 concentration, Fe(II) concentration, pH and reaction time were 0.033 mol/L, 0.011 mol/L, 3 and 145 min, respectively, with 58.3% COD, 79.0% color and 82.1% iron removals.     

冲积河流滩槽定量划分方法及应用

通过理论分析与数值计算,研究了冲积河流漫滩水流水力因子的变化特性。结果表明,断面平均流速在漫滩瞬间迅速减小,然后逐渐增大;断面综合动能修正系数、动量修正系数均随水深而缓慢增加,在漫滩瞬间迅速增大,随即快速减小。根据漫滩水流水力因子沿水深的变化特性,提出采用断面横向平均流速为判别因子以定量划分复式断面的滩与槽。此外,文中将其应用于黄河下游漫滩水流的水沙数值模拟,其结果与实际情况符合较好。     

论会计电算化对审计的影响及对策

会计电算化的实施,给审计工作带来很大的影响。本文从会计电算化的基本内涵出发,将会计电算化对审计的影响从几个方面进行了分析,并提出了相应的对策。     

Utility Averaging Policies—Impact on Consumer's Energy Usage

Average Monthly Payment (AMP) plan is a utility policy designed to assist consumers in need such as low income and elderly. This study examines whether this utility policy is an advantage to these target customers. Results indicate that, with a muted price signal, the AMP plan produces an effect contrary to the objective of assisting low and fixed income consumers. Further, the study indicates consumers on the AMP plan consume more energy and the AMP plan does not appear to support energy conservation and efficiency.