Adjusting the economy to the new energy realities of the second half of the age of oil

Our research indicates that, due to the depletion of conventional, and hence cheap, crude oil supplies (i.e. peak oil), increasing the supply of oil in the future would require exploiting lower quality resources (i.e. expensive), and thus will most likely occur only at high prices. This situation creates a system of feedbacks where economic growth, which requires more oil, would require high oil prices that will undermine that economic growth. We conclude that the economic growth of the past 40 years is unlikely to continue unless there is some remarkable change in how we manage our economy.     

氢化物诱致金属稳态裂纹扩展数学模型理论研究

在温度和裂尖速度恒定、平面应变和小范围氢化物沉淀条件下,给出了考虑氢扩散、氢化物沉淀、非机械能量流和氢化物/固溶变形等多物理场的耦合效应的数学模型.导出了应力态金属中氢固态溶解度解析表达式,可用于描述不同弹性性态及任意几何形状的氢化物,其中氢化物和金属相假设为具有完全各向异性的力学性态.研究表明,当接近氢化学平衡和临近应力强度因子阈值裂纹扩展时,静水应力平台在临近裂尖氢化物沉淀的区域产生.静水应力平台强烈依赖于远场氢浓度和温度,但几乎与金属材料的屈服强度和硬化特性无关.同一静水应力也在产生氢化物的裂尖后面出现.裂尖场附近的特性用于估计远场氢浓度阈值(而且发现低于此阈值时不会产生氢化物沉淀)和应力强度因子阈值.当归一化应力强度因子接近零时,临近应力强度因子阈值的裂尖场产生,它可由氢化物沉淀区域的常静水应力体现.随着归一化应力强度因子值的增加,裂纹扩展裂尖场从阶段Ⅰ演化到阶段Ⅱ,氢化物沉淀区域的实际尺寸减小并偏离平台水平,裂尖场附近的力学响应基本和金属中不充有氢的工况一致,此时裂尖场强烈依赖于远离裂尖场的氢浓度.     

Toxicity of Heavy Metals on Scenedesmus quadricauda (Turp.) de Brébisson in Batch Cultures (7 pp)

Background Aquatic environments are often exposed to various pollutants like heavy metals that are released from industrial, agricultural and domestic wastes. Emissions of heavy metals can then enter all ecosystems and bring about severe problems in plants, especially algae depending on the concentrations of a given element. The objective of the investigation presented is to detect toxic effects due to some heavy metals in the biomass of green alga Scenedesmus quadricauda. Methods All experiments were conducted with axenic cultures of the green alga Scenedesmus quadricauda (Turp.) de Brebisson (Chlorococcales, Chlorophyta). The cultures were grown in Chu-no.10 medium, and optimum physical and chemical growth conditions were provided to get higher growth rates and lower doubling times of cells. Growth of the micro algal cultures was measured on a daily schedule by counting cultures and determination of chlorophyll-a. The sterile-filtered heavy metal concentration solutions (Cd, Pb and Cu) were prepared and added as stock solutions of their salts (CdCl2*2.5 H2O, Pb(NO3)2*H2O and CuSO4*5 H2O). Results and Discussion The growth decreased gradually with the alga exposed to Cd at 0.05, 0.1, and 0.5 mg/L in comparison with the control whereas 1 mg/L Cd2+ had a clearly destructive effect. The growth was decreased with Pb at 15, 20 and 25 mg/L gradually, while at 30 mg/L the effect was more pronounced. When Cu was used, the growth was increased gradually at 0.5, 1 and 1.5 mg/L and vice versa at 2 mg/L. Conclusion There were differences in toxic effects of the metals with different metal as well as their concentrations and the time of exposure.     

资源型旅游地增长极限的理论模型

在经济发展中,国内诸多地区都将旅游业发展作为支柱产业,但对其长期有效性却缺少理论和实证的探讨。一些落后地区虽然靠旅游发展获得第一桶金。走的是资源经济之路。但带动效益有限。本研究运用最新的发展理论,在对典型资源型旅游地作分析的基础上,建立了资源型旅游目的地发展的一般结构模型,并指出导致资源型旅游地发展的内部限制性因素。本研究希望更多的研究人员关注这一问题,从理论和实证上丰富和验证本文提出的理论假设。     

从清洁生产到循环经济

清洁生产和循环经济是20世纪90年代以来在我国引人注目的两项实践。正确认识、积极推进清洁生产和循环经济,对于转变我国经济增长方式与发展模式、促进可持续发展具有重要意义。在将资源环境要素纳入经济系统内部,转变经济增长方式,促进资源环境和经济结合一体化发展模式的概念意义下,本文从宏观历史层面阐述了我国清洁生产和循环经济的发展过程、必然趋势及其长期曲折、交错推进的过程特征。分析了以废物循环作为循环经济的认识和实践误区,提出了以清洁生产为基础推进产业生态化,结合强化末端管制,以及围绕建立“绿色”市场进行制度创新为基本内容的发展我国循环经济的建议。     

中国收入差距与环境质量关系的实证检验--基于对环境库兹涅茨曲线的扩展

在对环境库兹涅茨曲线（EKC）假说扩展的基础上,分析和验证了收入差距与环境质量之间的关系。应用联合国统计司公布的中国1986—2002年度二氧化碳排放总量数据,通过计量模型论证收入差距与环境质量之间的假设。结果发现,收入差距扩大会刺激二氧化碳排放,收入差距越大这种影响的效果就会越恶劣。而且收入差距因素还会通过作用于经济增长,促使经济增长对环境的污染程度加强。延迟转折点的到来。因此,我国目前在促进经济增长的同时,要以提高社会整体福利为目的,缩小居民收入差距,这将有利于环境质量的改善和提高。     

采煤区覆岩与地表沉陷控制技术研究及展望

煤矿开采引起覆岩及地表沉陷的控制理论与技术研究是涉及全球性灾害学科的研究内容之一。笔者通过对采动覆岩破坏特征的分析，提出了覆岩破坏与移动的“竖四带”的分区模式；并在评述传统控制技术及效果的基础上，介绍了覆岩与地表沉陷控制的新技术——离层注浆技术的原理、特点及应用前景