清洁生产和末端治理环境绩效对比分析

以吉林省为例,应用无残差完全分解模型,将工业污染产生量和排放量的变化分解为规模效应、空间结构效应和技术效应,分析清洁生产和末端治理不同产业生态化策略导向下的环境绩效,探索产业生态化发展改进方向.结果表明:清清生产的控污效果在数量上大于末端治理的减排效果,产业生态化发展表现出以预防策略为主的特征.但是,环境目标主要通过清...     

The empty shell of the planetary: re-rooting the urban in the experience of the urbanites

ABSTRACT

This paper offers reflections on a body of work that has been produced under the label of “planetary urbanization”. This term has its roots in speculative work by French writer Henri Lefebvre in the late 1960s and early 1970s and has recently been popularized by a new generation of critical urban theorists. In this commentary, I propose that Lefebvre’s idea of planetary urbanization (and the aligned concepts “complete urbanization” and “urban society”) offer a way to think productively about post-capitalist possibilities. Making reference to early writings by Marx and Engels about communism and the end of human pre-history, I argue that planetary urbanization presents a terrain for liberation from the constraints of capitalist histories. Given that this terrain is currently defined by the domains of neoliberalism and climate change a new politics is necessary to unlock the possibilities of urban society.     

不同温度及不同加热时间作用后混凝土力学性能试验研究

采用液压伺服试验系统对经历不同温度、不同加热时间作用后的混凝土力学性能进行了试验研究,分析了加热温度、加热时间对混凝土的抗压强度、弹性模量和应力—应变关系等力学性能的影响。结果表明：高温后,混凝土的力学性能随温度的升高而劣化,表现为随着受热温度的升高、加热时间的延长,混凝土的抗压强度、弹性模量降低,峰值应变逐渐增大。此外,还探讨了混凝土抗压强度、弹性模量和应力—应变关系随温度和加热时间变化的规律,得到了混凝土抗压强度、弹性模量随温度和加热时间变化的回归公式,比较回归曲线与试验曲线的结果表明,回归曲线能够很好地模拟试验曲线。     

膏岩三轴压缩试验及高温相变特征研究

采用伺服刚性试验机对天然膏岩开展三轴压缩试验,研究了温度及围压对膏岩强度及变形特性的影响。结果表明,膏岩在不同围压下均具有良好的塑性流动特性,加载后无明显的剪切破坏面,而是出现明显的侧向膨胀。根据三轴试验结果,利用摩尔-库仑定律得到了膏岩的强度准则及抗剪强度参数。升高温度导致膏岩强度降低,且高温下石膏发生晶型转变,从二水石膏脱水转变为半水石膏,利用扫描电镜和X衍射对此过程进行了研究。脱水过程导致瞬间孔隙应力增加,膏岩破坏特性由延性转变为脆性。随着持续加载,破裂断面逐渐愈合。膏岩显著的塑性流动能力及快速的裂隙愈合能力对于天然气盖层的封闭稳定性具有重要意义。     

测量上海产业网络的点入度和点出度——超越后工业化社会的迷思

利用上海市2007年144个部门投入产出表,计算基于投入产出完全消耗系数的点入度和点出度,将产业划分为Ⅰ型（高点入度、高点出度）,Ⅱ型（低点入度、高点出度）,Ⅲ型（低点入度、低点出度）,Ⅳ型（高点入度、低点出度）。研究发现：① Ⅰ型、Ⅱ型、Ⅲ型和Ⅳ型制造业点入度均值分别比各类型服务业高0.52、0.45、0.04、0.27,表明制造业相对服务业具有更强的后向拉动效应。② Ⅱ型和Ⅳ型服务业点出度均值分别高于Ⅱ型和Ⅳ型制造业0.29、0.16,而Ⅰ型和Ⅲ型服务业点出度均值分别小于Ⅰ型和Ⅲ型制造业0.32、0.17,表明服务业的前向拉动效应存在着分异。③ Ⅰ型、Ⅳ型制造业及服务业的点出度对GDP均具有正向的相关性,提高对这些产业的使用有利于提升GDP。Ⅱ型服务业的点入度对GDP具有负向的相关性,点入度较低的房地产开发经营业、银行业、证券业GDP分别为该类服务业前3名。Ⅱ型服务业点出度、Ⅲ型制造业和服务业点入度和点出度对GDP的回归系数均未通过显著性检验。尽管制造业GDP占比下降,制造业仍在上海产业网络中发挥着重要的作用。上海应超越后工业化的迷思,降低对房地产业的依赖,加强制造业与服务业的融合发展,特别是加强金融对制造业等实体经济的支持,提升产业网络关联多样性和非关联多样性,促进航空、航天、机器人等新兴产业的发展。     

有限群p-超可解性的一个判别准则

为了得出群的p-超可解性的一些判别准则,引入有限群的z-置换嵌入子群的概念。设z是群G的Sylow子群的完全集,群G的一个子群H称为在G内z-置换嵌入,如果H的每个Sylow子群也是G的某个z-置换子群的Sylow子群,一些已知的结论也得到推广。     

基于城镇化视角的绿洲城市用水变化驱动效应分析

城镇化是驱动区域用水变化的双刃剑,既可以通过刺激生产来促进用水总量增长,也可以通过优化用水结构和提高用水效率来抑制用水总量增长。以黑河流域张掖市为例,通过构建城镇化驱动用水变化的完全分解模型,定量测度了2000-2011年张掖市人口和经济城镇化过程对用水总量和用水效率变化的驱动效应。结果表明：张掖市人口和经济城镇化过程对用水总量均具有明显的减量效应,对用水效率均具有明显的增量效应,而且与人口和经济城镇化速度高度相关。因此建议干旱区绿洲城市在水资源约束下,应将城镇化作为优化人口结构、经济结构和用水结构,提高经济效率以及用水效率,并最终实现水-生态-经济良性循环的抓手。该结论对于科学认识干旱区绿洲城市城镇化与水资源利用的关系具有一定的参考价值。     

岩石试件端面摩擦效应数值模拟研究

试件端面摩擦效应直接影响试件内的塑性等效应变、侧向位移的分布和单元应力应变曲线。本文运用ANSYS中的接触单元模拟了平面应变状态下端面摩擦效应对塑性等效应变、侧向位移和单元应力应变曲线的影响,得到了不同摩擦系数时塑性等效应变及侧向位移的渐进变化形式。当接触面摩擦较小时,塑性等效应变图案为上下两个X形网络,侧向位移上下分布均匀;当接触面摩擦增大时,塑性等效应变网络向中部靠拢并且明显增大,侧向位移上下分布不均匀,中部较上下端面位移大;当试件端面侧向位移被限制,即摩擦力很大时,塑性等效应变网络变为一个X形局部化带,侧向位移分布更加不均匀,中部明显隆起。     

Sound Velocity of Seafloor Sediment and its Response under Axial Stress-Strain

The results of axial stress-strain measurements made from short columnar samples of seafloor shallow surface sediment in the southern South China Sea area indicate that there are three kinds of variations in the longitudinal wave sound velocity, which are related to such characteristics as physical-mechanical properties, grain contact status and grain structure and microstructure of the submarine shallow surface sediment. This study may make theoretical contributions to further understanding the reliability of various submarine sediments in the southern South China Sea as bearing interfaces and such scientific objectives as phonotelemetering and remote sensing of the engineering mechanical properties of seafloor sediment.     

Study of dilatancy behaviors of calcareous soils in a triaxial test

Abstract

In this article, the dilatancy of calcareous soil is studied systematically based on triaxial consolidation drainage shear tests, and the difference in dilatancy between calcareous soil and siliceous soil is also investigated. It was found that: ① Calcareous soil experience obvious dilated deformation. Dilatancy tendency increases with increasing related density and decreases with increasing confining pressure. ② The volumetric strain rate initially increases from negative to positive. After it reaches a maximum, there is a small decrease in the volumetric strain rate, but it is still greater than zero, and the stress-strain curves are of softening type. ③ For the same condition, the dilatancy deformation of calcareous sand begins later than that of siliceous sand, and the volume compression before dilatancy is also larger for calcareous sand. ④ The critical state alone cannot accurately describe the entire deformation process of soil, and it is proposed that the phase transformation state be added to the standard method used to assess soil dilatation and contraction. ⑤ Based on the statistical analysis of experimental data, mathematical relationships were established between void ratio, relative density, and effective confining pressure of phase transformation state and critical state, respectively.

• Highlights

• Reports results from a well-designed experiment that includes a good amount of samples and data.

• Effects of relative density and effective confining pressure on deformation mode and mechanical properties of calcareous sand are evaluated.

• The difference in dilatancy between calcareous sand and siliceous sand was compared

• The phase-transformation state and critical state were compared with the axial strain, volumetric strain and deviatoric stress.

• Using phase-transformation void ratio and critical void ratio to describe the whole deformation process of calcareous sand is proposed.

• The mathematical expressions of phase-transformation void ratio and critical void ration were given, respectively.