超声波-曝气协同降解聚丙烯酰胺溶液的研究

研究了超声波-曝气协同工艺降解聚丙烯酰胺溶液的条件和效果。结果表明,在超声波处理聚丙烯酰胺溶液时,引入曝气后,比单纯超声的降解效率大有提高。     

The Relationship between Economic Growth and Environmental Quality in Beijing： A Verification of the Environmental Kuznets Curve

This paper empirically examines Environmental Kuznets Curve （EKC） with time series data for Beijing from 1985 to 1999. The results lead to two main conclusions： the environmental policy of Beijing and China governments has made the turning point of EKC come early, at around 3000-50005; and the relationship between economic growth and environmental degradation takes on an inverted-U, but different regions may have different turning points, different time-span for realizing the turning point of EKC, and different slopes for the rising-declining pattern.     

The community and public spaces: ecological thinking, mobility and social life in the open spaces of the city of the future

The roots of the present crisis of public urban spaces in the modern and contemporary city can be traced back not only to the history of the early vision of the planning movement to which the city planning discipline dedicates much attention, but also to the history of scientific thinking, the measuring eye that all of us—specialists, administrators, intellectuals and citizens alike—have used on it from the 17th century up to the present day. Recognition of these roots allows us to distinguish the fruitful from the sterile among the many directions offered by the various projects for the city of today and the city of the future. In the recent emphasis placed on the concept of community—in the interpretation offered here—lies the basis and motivations of some of the most interesting guidelines for an in-depth study and really innovative approach to the problems of city traffic and the closely associated problems of the reappropriation of a social dimension of public space for the city of the future.     

基于灰色关联法的甘南草地退化影响因素分析——以碌曲县为例

科学合理地制订恢复和改善甘肃省碌曲县草地的措施,必须首先明确影响草地退化的因素中哪种影响力度最大。采用灰色关联法对碌曲县草地退化因素系统中母因素与子因素的关系密切程度进行定量分析,结果表明,人文因素是影响碌曲县草地退化的主导因素。影响碌曲县草地退化的人文因素可归纳为牧业结构调整因子、牧民家庭支出因子和牧业劳动人口因子三个因子。采用系统聚类分析法,对人文因素进行聚类,并对其影响作用进行定性分析,得知遏制草地退化的关键在于拓宽牧民家庭收入渠道、提高牧民收入等。     

内蒙古草原过度放牧的解决途径

内蒙古草地资源丰富,但面临着逐年退化、面积日益缩小的危机,其中草原过度放牧是重要原因之一。本文基于内蒙古草原面积过百万(公顷)的31个旗县的数据测算了全区草原过牧的程度,结果表明,内蒙古草原过牧率高居70%左右,而且过牧程度由轻度转向中度。最后本文对内蒙古草原过牧的原因进行了深入分析,并提出了相应的对策建议。     

试论土地保护学

论述了土地保护学的对象、性质、理论基础、内容体系及其研究方法 ,阐述了土地保护学与其相邻学科的关系。     

Tenants, Landlords, and Soil Conservation

It has long been argued that tenants tend to overexploit land, but this conventional wisdom has been derived largely without consideration of landlords' actions. We examine what happens when landlords can invest in durable conservation measures in addition to choosing rental contract terms. When tenants are risk neutral, landlords overinvest in conservation under cash rental contracts but can achieve first best levels of output and protection against land degradation when conservation investment is combined with share rental. When tenants are risk averse, the first best is unattainable. In this case, conservation investment combined with share rental results in output levels below the first best, while equilibrium conservation investment may be greater or less than the first best. These results suggest that contract form and conservation investments are likely made simultaneously, so that econometric studies of conservation practice adoption that treat rental status as exogenous are likely subject to bias.     

土地退化平衡导向下国土空间生态保护修复的路径选择

研究目的：归纳阐释土地退化平衡（LDN）对国土空间生态保护修复的理论意蕴，回答LDN导向下国土空间生态保护修复的路径选择。研究方法：逻辑推理法、归纳演绎法。研究结果：（1）LDN具有鲜明的时空特征和明确的响应层次，并遵循“同类平衡（Like for Like）”与“一票否决（One out-All out）”原则。（2）新形势下土地资源的空间载体、生态本底、安全保障、服务双碳目标等功能得到拓展，客观上要求生态保护修复协调好尺度与格局、要素与系统、食物与生态、减排与增汇之间的关系。（3）LDN对生态保护修复的理论意蕴包括多尺度嵌套的动态平衡、多目标权衡的系统治理、多手段协同的实现路径。（4）基于LDN的国土空间生态保护修复策略包括：构建“功能—尺度”与“要素—系统”相耦合的LDN目标函数，引导生态保护修复目标量化；制定螺旋递进式“分区管控—分级治理—分类施策”的管理策略，促进自然与行政区划在空间上的有效衔接；建立“干预管制—激励竞争—强制倒逼—差别治理”协同的保障机制，协调“自然—社会—政府—市场”等多部门关系。研究结论：LDN在国土空间生态保护修复实践中具有积极的理论意义与现实价值，能...