基于DEA的中国农地非农化效率及其变化

基于DEA和Malmquist TFP指数模型方法研究分析2000～2008年我国省域和区域层面农地非农化效率及其变化,为优化土地利用提供参考。研究结果表明：（1）省域层面各项平均效率水平一般,超过80%的省份农地非农化综合效率未达到有效状态;（2）农地非农化效率总体呈现东部地区>东北地区>中部地区>西部地区的状态,区域差距呈现缩小趋势;（3）农地非农化平均综合效率的提升主要源于纯技术效率的贡献,而生产效率的明显改善得益于技术进步;（4）东部和东北地区农地非农化综合效率有所下降,中西部地区综合效率呈现上升趋势,西部地区上升显著。通过研究发现：现阶段我国农地非农化存在要素资源的利用不充分现象,效率提升潜力较大;西部地区农地非农化规模集聚能力与其他地区差距较大;东部地区存在农地非农化效率损失;虽然中西部地区农地非地化效率变化提升明显,但能否成为农地非农化指标增加的依据还值得进一步探讨     

中国CO《,2》排放的影响因素分解与预测

我国正处于2008年美国金融危机影响下,刺激经济一系列政策的落实观测期,要实现单位国内生产总值CO<,2>排放的目标,任务十分艰巨.本文采用投入产出结构分解技术,对1997-2004年我国应对亚洲金融危机时期的CO<,2>排放量变动进行了7因素的分解测算,结果表明经济增长是CO<,2>排放上升的主要驱动力,能源节约是驱动我国CO<,2>排放下降的主要因素,经济结构变动的影响相对较小.特别,国内最终需求、出口成长以及出口结构变动均推动CO<,2>排放上升,国内最终需求结构变动以及能源替代表现出了对CO<,2>排放的抑制影响等.同时,在我国经济"三步走"目标的前提下,结合能源节约设计了CO<,2>排放的3类情景,给出了未来CO<,2>排放的态势预测,提出了加强需求结构调整、能源效率提高以及可再生能源开发利用的保增长与CO<,2>减排并行不悖的建议.     

Temporal genetic variability and host sources of Escherichia coli associated with fecal pollution from domesticated animals in the shellfish culture environment of Xiangshan Bay, East China Sea

This study was conducted to analyze the genetic variability of Escherichia coli from domesticated animal wastes for microbial source tracking (MST) application in fecal contaminated shellfish growing waters of Xiangshan Bay, East China Sea. (GTG)₅ primer was used to generate 1363 fingerprints from E. coli isolated from feces of known 9 domesticated animal sources around this shellfish culture area. Jackknife analysis of the complete (GTG)₅-PCR DNA fingerprint library indicated that isolates were assigned to the correct source groups with an 84.28% average rate of correct classification. Based on one-year source tracking data, the dominant sources of E. coli were swine, chickens, ducks and cows in this water area. Moreover, annual and spatial changes of E. coli concentrations and host sources may affect the level and distribution of zoonotic pathogen species in waters. Our findings will further contribute to preventing fecal pollution in aquatic environments and quality control of shellfish.     

Long-term Trends in Surface Water Quality of Five Lakes in Japan

Since 1983, the Ministry of the Environment of Japan has conducted nation-wide acid deposition surveys. To investigate the effects of acid deposition on surface water, we used the nonparametric Mann–Kendall test to find temporal trends in pH, alkalinity, and electrical conductivity (EC) in more than 10 years of data collected from five lakes and their catchments (Lake Kuttara: northernmost; Lake Kamakita: near Tokyo; Lake Ijira: central; Lake Banryu: western; and Lake Unagiike: southernmost). The pH of Lake Ijira water has declined slightly since the mid-1990s, corresponding with the downward trends seen in the pH and alkalinity of the river water flowing into the lake. There were significant upward trends in the EC of both the lake and stream water; the same trends were also found for concentrations. These trends show evidence of acidification due to atmospheric deposition, and this is the first such finding in Japan based on significant long-term trends. Lake Ijira is located about 40 km north of the Chukyo industrial area near Nagoya. The annual depositions of H⁺, nss-, and in Lake Ijira were among the highest of all deposition monitoring sites, suggesting that this is the main cause of the significant acidification observed in Lake Ijira. No significant trends suggesting acidification were observed in any of the other lake catchments in spite of the significant upward trends in EC. Upward trends in pH and alkalinity at Lake Banryu and upward trends in alkalinity at Lake Kamakita were detected, but no change in pH or alkalinity at Lake Kuttara and Lake Unagiike was observed.     

安徽地震活动期的划分与地震活动趋势的研究

20世纪以来安徽与中国大陆地震活动呈同步活跃关系。本文对安徽的地震活动周期进行了划分 ,并用综合统计分析方法进行安徽未来地震活动趋势研究 ,结果表明 :安徽目前正处在一个相对较弱的地震活动期 ,该活动期约在 2 0 0 6年前后结束 ,估计发生地震的最大震级为 5级左右 ,可能主要是 4～ 5级地震活动。     

污染生态学的研究前沿与展望

根据污染生态学国内外研究现状与发展趋势 ,对该领域的最新研究前沿进行了较为系统的分析和归纳。与此同时 ,从生态学发展战略的角度 ,对今后的研究重点进行了阐述。认为污染生态过程是污染生态学研究的中心议题 ,污染生态修复与污染生态工程是污染生态学应用研究的重点。通过研究 ,将会推动污染生态化学和污染生态毒理学等学科新的生长点和新的分支学科的形成和发展。     

软土深基坑的空间变形特性分析及危险性评估

为准确掌握软土深基坑的变形特性,并合理评价其危险性,基于现场监测成果,进行基坑重要监测项目的空间变形特征分析;通过变形分级和发展趋势判据计算得到相应特征指标,从而开展基坑危险性评估.结果表明:支护结构的空间变形近似呈"驼峰"特征,即基坑两端头的变形值相对较小,而基坑中部的变形值相对较大;周边土体沉降相对较小,随着与基坑...     

不确定性水质模型及其研究进展

水环境是一个充满不确定性因素的复杂巨系统,研究这些不确定性的变化有利于提高人们对水环境分析的认识和做出更切合实际的决策.详细、清晰地评述了不确定性水质模型研究的必要性、研究的方法和国内外研究进展等,并针对此类模型研究与应用过程中普遍存在的一些问题、主要表现和成因进行了分析与论述,最后结合目前的研究热点指出了今后不确定性水质模型发展的3个重要方向.     

储存试验站的温湿度特征分析研究

从温湿度的变化趋势、年较差、极端最高值、极端最低值等方面分析研究了储存试验站(长春、无锡、广州、西沙和拉萨)从1995-2005年的监测数据.结果表明,5地的温度变化趋势基本一致,而湿度变化趋势则不同.年较差最大的是长春,最小的是西沙.极端最高温度最高的是无锡;极端最低温度最低的是长春.广州的极端最高湿度最大;拉萨的极端最低湿度最小.5地的温湿度在变化趋势上有相似之处,但更多的是差异性.因而,在进行环境应力的信息开发应用时,应综合考虑温湿度多方面的特性.     

垃圾填埋场渗滤液处理研究进展

文章综述了垃圾填埋场渗滤液的研究情况,包括渗滤液的产生、危害、水质和水量、控制和处理,并提出了今后的研究方向,供从事此项研究的工作人员参考