高压静电场对火电厂循环冷却水阻垢效果及机理

利用双通道工业循环冷却水分析测试台和高压静电水处理器,对火电厂的冷却水进行阻垢效果和机理研究。结果表明,施加工作电压2．0～4．0kV时,平均阻垢率随电压的升高而增大,达到61．7％,以后随着电压的升高平均阻垢率呈下降趋势,在7．5kV电压作用下平均阻垢率43．4％。对垢样晶体的SEM扫描图片表明,经高压静电场处理前的水垢晶体以方解石型硬垢为主,处理后发生了晶型转化,转化为文石型软垢,有利于垢的去除。     

Biodegradation of endosulfan-contaminated soil in a pilot-scale reactor-bioaugmented with mixed bacterial culture

A novel mixed bacterial culture was enriched from an endosulfan (6, 7, 8, 9, 10, 10 – hexachloro-1, 5, 5a, 6, 9, 9a-hexahydro-6, 9-methano-2, 3, 4-benzo (e) dioxathiepin-3-oxide) processing industrial surface soil. The cultures were successful in the degradation of aqueous phase endosulfan in both aerobic and anaerobic conditions. Using the cultures, endosulfan degradation in silty gravel with sand (GM) was examined via pilot scale reactor at an endosulfan concentration of 0.78 ± 0.01 mg g^{? 1} of soil, and optimized moisture content of 40 ± 1%. During operation, vertical spatial variability in endosulfan degradation was observed within the reactor. At the end of 56 days, maximum endosulfan degradation efficiency of 78 ± 0.2% and 86.91 ± 0.2% was observed in the top and bottom portion of the reactor, respectively. Both aerobic and anaerobic conditions were observed within the reactor. However, endosulfan degradation was predominant in anaerobic condition and the total protein concentration in the reactor was declined progressively down the soil depth. Throughout the study, no known intermediate metabolites of endosulfan reported by previous researchers were observed.     

Large‐Scale Fine‐Resolution Hydrological Modeling Using Parameter Regionalization in the Missouri River Basin

This study simulated crop and water yields in the Missouri River Basin (MRB; 1,371,000 km²), one of the largest river basins in the United States, using the Soil and Water Assessment Tool (SWAT) at a fine resolution of 12‐digit Hydrological Unit Codes (HUCs) using the regionalization calibration approach. Very few studies have simulated the entire MRB, and those that have developed were at a coarser resolution of 8‐digit HUCs and were minimally calibrated. The MRB was first divided into three subbasins and was further divided into eleven regions. A “head watershed” was selected in each region and was calibrated for crop and water yields. The parameters from the calibrated head watershed were extrapolated to other subwatersheds in the region to complete comprehensive spatial calibration. The simulated crop yields at the head watersheds were in close agreement with observed crop yields. Spatial validation of the aggregated crop yields resulted in reasonable predictions for all crops except dryland corn in a few regions. Simulated and observed water yields in head watersheds and also in the validation locations were in close agreement in naturalized streams and poor agreement in streams with high groundwater‐surface water interactions and/or reservoirs found upstream of the gauges. Overall, the SWAT model was able to reasonably capture the hydrological and crop growth dynamics occurring in the basin despite some limitations.     

种粮大户扩大农地规模意愿存在盲目性吗?

种粮大户扩大农地经营规模出于什么样的动机?是否存在盲目性?这一问题的答案不仅关系到粮食安全问题,也关乎到农村土地流转和农业适度规模经营政策等重大问题。本文基于2015年1月和8月对安徽省种粮大户的两次实地调研数据,建立heckman两阶段模型和解释结构模型(ISM),检验种粮大户扩大农地规模意愿是否存在盲目性并探寻导致规模扩张意愿的因素及其作用机制。研究发现:种粮大户扩大规模意愿强烈,且在不同农户间扩张意愿差异显著;影响其扩大规模意愿及意愿强度的浅层次因素为农户借贷能力,其中,民间借贷途径、正规金融贷款经验对扩大规模意愿的正向影响作用显著;中层次因素为家庭资源禀赋,其中家庭资本禀赋不足对农户扩大规模意愿及强度产生显著正向的影响,家庭劳动力数量对农户扩大规模意愿强度有显著负向影响;深层次因素为同行态度、家人态度、政策激励等外部环境因素,其中,同行态度、家人态度、获得荣誉称号、获得物质奖励等因素对扩大规模意愿的正向影响作用显著。研究结果表明,种粮大户规模扩展意愿存在一定的盲目性,究其原因:一是种粮大户强烈的逐利动机和较强的风险偏好,农户几乎完全褪去生计生产者的身份,家庭资源不足使得农户依赖于借贷满足扩大生产意愿,表现出对债务风险的偏好;二是粮食生产规模化进程中同行、家人的主观规范及一味求快贪大的行业政策激励导向。鉴于此,应加强现代企业管理知识培训,提升种粮大户科学管理和科学决策水平;建立粮食生产适度规模风险监测预警机制;调整政策导向、行业导向和舆论导向以抑制种粮大户的盲目扩张行为。     

Ecological Tax Reform: Many Know Why But Few Know How

Ecological tax reform involves the utilisation of the tax system to facilitate sustainable development. The generally accepted approach to ecological tax reform is to reduce tax rates on income and labour and to impose Pigouvian taxes on resource use and pollution emissions. While this approach is a vast improvement on current tax systems, it is an inadequate means of achieving sustainable development because it relies exclusively on the manipulation of market prices – an allocation instrument – when ecological sustainability is a throughput problem that requires a separate policy instrument to be adequately resolved. With the aid of a linear throughput representation of the economic process, it is argued that conventional ecological tax reform measures promote just two of the five behavioural modes put forward to achieve sustainable development. In order to promote all five behavioural modes, it is argued that ecological tax reform is best conducted with the incorporation of tradeable resource use permits and assurance bonds.     

水石流概化水槽试验相似律的探讨

针对水石流粒粗,粘性小的特点,提出了利用水槽进行分段模拟水石流的设想,首次通过几何率解决难度较大的阻力相似问题,改变以往过度加糙的方式,通过变粒径尺度的方法消除了相模型沙级配不连续相似的问题,较好地实现了固体物质级配相停,达到了泥石流的密度相似和输沙相似,通过水槽概化模型实验实例,对本方法进行了验证。     

区域污染治理能力与排污规模的协调性评价

为分析区域排污规模与污染治理的协调性,构建了排污规模与污染治理协调度模型,并以2006、2013年的数据对模型进行实证分析。结果表明,制约排污规模和污染治理协调性的主要矛盾是污染治理能力的落后,全国70%以上地区污染治理能力均滞后于污染物产生规模;国内治理能力在研究期间不断提高,区域差异在不断缩小,治理能力过度滞后的省份由14个减少到2个;除江苏外2013年其余各地区均有1项或多项污染物的治理能力滞后,其中生活废水治理能力滞后的区域最多;经济发展水平是影响协调性的重要因素,2013年协调度与地区人均GDP基本呈线性关系。模型实证计算结果与主观判断也较为吻合,具有一定的推广应用价值。     

基于专利的企业环境技术创新水平研究

以专利为衡量技术创新水平指标,对国内外企业环境技术创新水平的差异进行了分析.研究结果表明,1986～2005年期间,国内外企业环境技术创新水平逐年增强,不过我国企业的环境技术创新主体地位仍未建立;同国外企业相比,我国企业的原始技术创新能力不强.由于国内企业技术创新受到经济因素的影响,节约资源和清洁能源类环境技术比污染控制技术较多一些.在环境技术创新领域,无论国内还是国外,规模大、国际知名度高的企业占据了重要地位.基于我国企业仍未具备很强的环境技术创新能力,建议国家在构建环境技术创新体系时,应增加企业环境技术创新的经济、人力投入,尤其需要加强对大型企业环境技术创新的支持力度,发挥其规模效应.     

Assessment and mapping of environmental quality in agricultural soils of Zhejiang Province, China

Heavy metal concentrations in agricultural soils of Zhejiang Province were monitored to indicate the status of heavy metal contamination and assess environmental quality of agricultural soils. A total of 908 soil samples were collected from 38 counties in Zbejiang Province and eight heavy metal （Cd, Cr, Pb, Hg, Cu, Zn, Ni and As） concentrations had been evaluated in agricultural soil. It was found 775 samples were unpolluted and 133 samples were slightly polluted and more respectively, that is approximately 14.65% agricultural soil samples had the heavy metal concentration above the threshold level in this province by means of Nemerow＇s synthetical pollution index method according to the second grade of Standards for Soil Environmental Quality of China （GB15618- 1995）. Contamination of Cd was the highest, followed by Ni, As and Zn were lower correspondingly. Moreover, Inverse Distance Weighted （IDW） interpolation method was used to make an assessment map of soil environmental quality based on the Nemerow＇s pollution index and the soil environmental quality was categorized into five grades. Moreover, ten indices were calculated as input parameters for principal component analysis （PCA） and the principal components （PCs） were created to compare environmental quality of different soils and regions. The results revealed that environmental quality of tea soils was better than that of paddy soils, vegetable soils and fruit soils. This study indicated that GIS combined with multivariate statistical approaches proved to be effective and powerful tool in the mapping of soil contamination distribution and the assessment of soil environmental quality on provincial scale, which is beneficial to environmental protection and management decision-making by local government.     

农地流转对农地与劳动力资源利用效率的影响——基于甘肃省农户调查数据的实证研究

本研究采用倾向得分匹配法（PSM）分别就农地流转对农地、农业劳动力、非农劳动力和总劳动力资源利用效率的影响进行了分析。结果表明,农户的农地转入和转出行为都能有效提高总劳动力资源利用效率,而农地转出行为在一定程度上降低了农地资源利用效率。农地转入户的总劳动力和农业劳动力资源利用效率比未参与流转的农户分别高2026.153元/人和4844.289元/人,两组农户间的农地资源利用效率差异不显著;农地转出户的总劳动力和非农劳动力资源利用效率比未参与流转的农户分别高3315.577元/人和2581.883元/人,其农地资源利用效率比未参与流转的农户低466.488元/亩。因此,农地流转不一定会提高农地资源利用效率,但有利于促进农村劳动力专业化,从而提高农村总劳动力资源利用效率。