The relationship between energy consumption structure,economic structure and energy intensity in China

This paper investigates the long-run equilibrium relationships, temporal dynamic relationships and causal relationships between energy consumption structure, economic structure and energy intensity in China. Time series variables over the periods from 1980 to 2006 are employed in empirical tests. Cointegration tests suggest that these three variables tend to move together in the long-run. In addition, Granger causality tests indicate that there is a unidirectional causality running from energy intensity to economic structure but not vice versa. Impulse response analysis provides reasonable evidences that one shock of the three variables will cause the periods of destabilized that followed. However, the impact of the energy consumption structure shock on energy intensity and the impact of the economic structure shock on energy consumption structure seem to be rather marginal. The findings have significant implications from the point of view of energy conservation and economic development. In order to decrease energy intensity, Chinese government must continue to reduce the proportion of coal in energy consumption, increase the utilization efficiency of coal and promote the upgrade of economic structure. Furthermore, a full analysis of factors that may relate to energy intensity (e.g. energy consumption structure, economic structure) should be conducted before making energy policies.     

Energy intensity of maritime trades: Evidences from the EX-TREMIS database

This paper describes the energy consumption performance of sea-going ships engaged in the EU27 seaborne trades based on data and parameters resulting from the EX-TREMIS (EXploring non road TRansport EMISsions in Europe) database. EX-TREMIS is a comprehensive database of fleet and transport activity data, specific energy consumption, emission factors and total emissions from rail, maritime and air transport in the European Union. The EX-TREMIS maritime model derives from a mixture of top–down and bottom–up approaches for estimating pollutant emissions from shipping activities. The model did not use direct observations of actual trips, but empirically derived the number of equivalent-ships. Cargo type shipments were linked to seven ship type categories for which a further segmentation by ship size (three length classes), type and age of the main engine and type of fuel was applied.     

鲁中选矿厂钴回收的探讨

鲁中冶金矿业集团公司所属的港里矿2003年开始首采.随着开采量的不断增加,港里矿矿石成为选厂入选矿的主要来源,钴的赋存状态发生了变化,使钴的回收成为可能.试验表明,采用强磁抛尾-铜、钴混浮-铜、钴分离的流程效果较好.     

Application of bridging-law concepts to short-fibre composites Part 3: Bridging law derivation from experimental crack profiles

This is the third paper in a series of four where notch sensitivity, fracture energy and bridging laws are studied in short-fibre polymer composites. Here, bridging laws are derived from experimental crack-opening profiles in centre-hole notched tensile specimens. The materials studied are three types of commercial glass–mat composites with different reinforcement structures and matrices. The materials have softening bridging laws and the calculated fracture energies from bridging laws are in good agreement with values determined directly by experiment. The calculated maximum local bridging stress is found to be higher than the uniaxial tensile strength. An outline of a failure criterion for notched specimens based on the crack-bridging approach is presented.     

偶阶半线性阻尼泛函微分方程的振动性

研究了一类含有连续分布时滞和阻尼项的偶数阶中立型半线性微分方程,运用Riccati变换和H函数法,获得了该方程一切解均为振动的若干新的振动准则,推广和改进了已有文献的主要结果.     

铝材超薄快速铸轧状态下铸轧辊强度的有限单元法分析

运用有限元软件Algor和工程技术语言Matlab编程对两套正常使用的铸轧辊以及针对超薄快速铸轧而设计的铸轧辊进行了强度仿真计算，获得了超薄快速铸轧辊在热装配的预应力，轧制扭短以及轧制力等我应力场条件下的综合应力状态，并探讨了改善铸轧辊应力状态的策略及方法，为铸孔辊适应铝材超薄快速铸轧工艺提供了有效的分析方法，对改善铸轧辊的强度设计具有指导意义。     

遗传算法在暴雨强度公式优化问题中的应用及Matlab实现

介绍了遗传算法在实现暴雨强度公式优化问题中的应用,给出了在Matlab语言环境下实现编码、译码、选择、重组和变异各算子的编程方法,通过比较来说明遗传算法在寻求最优解的优越性。     

Restraint of fatigue crack growth by wedge effects of fine particles

This paper presents some experimental results which demonstrate restraint of fatigue crack growth in an Al–Mg alloy by wedge effects of fine particles. Fatigue test specimens were machined from a JIS A5083P‐O Al–Mg alloy plate of 5 mm thickness and an EDM starter notch was introduced to each specimen. Three kinds of fine particles were prepared as the materials to be wedged into the fatigue cracks, i.e. magnetic particles and two kinds of alumina particles having different mean particle sizes of 47.3 μm and 15.2 μm. Particles of each kind were suspended in an oil to form a paste, which was applied on the specimen surface covering the notch zone prior to the fatigue tests. In order to make some fracture mechanics approaches, in situ observations of fatigue cracks were performed for the two cases using a CCD microscope, with a magnification of ×1000. The crack length and the crack opening displacement (COD) at the notch root, δ, were measured. First it was ensured by control tests that the wedge effect of the oil itself was negligible. Then it was found that the large size alumina particles were not effective in restraining crack growth because the paste was difficult to make due to the large particle size and the particles could not enter the cracks properly. However, both of the magnetic particles and the small size alumina particles effectively restrained crack growth, especially the latter which produced 143–350% increase in the lifetime to failure. From the in situ observations, in the case of the small size alumina particles, a pronounced retardation of crack growth was observed immediately after the crack length exceeded 0.4 mm, and this is considered to be due to the range of COD value, δ_max ? δ_min , being strongly affected by the wedge effects of the particles. The crack retardation effect continues almost through the entire lifetime if the alumina paste is re‐applied at specified intervals, while the effect is apparently lost after the crack length exceeds ～2 mm when such re‐painting is not continued. After the fatigue tests, some macro‐ and microfractographic analyses were performed using a CCD microscope, a SEM and an EPMA (electron probe microanalyser), in order to examine the mechanism of fatigue crack restraint by the wedge effects of the fine particles. From those analyses, it was reasoned that the fine particles that entered a fatigue crack are subjected to cyclic pressures between the crack faces and then form a kind of wedge which causes significant levels of crack closure that restrain crack growth.     

Crack patterns in brittle thin films

The physical system studied is a brittle elastic film bonded to an elastic substrate with different elastic properties; a residual tensile stress is presumed to exist in the film. The focus of the study is the influence of the mismatch in elastic properties on patterns of crack formation in the film. The stress intensity factor and crack driving force for growth of a periodic array of cracks in the direction normal to the interface under two-dimensional conditions are determined for any crack depth and any mismatch in elastic parameters. It is found that, even for a relatively stiff film material, the stress intensity factor of each crack as a function of crack depth exhibits a local maximum. The driving force for crack extension in the direction parallel to the interface is then determined on the basis of these two-dimensional results, and the equilibrium spacing of crack arrays is estimated for given residual stress. The results of the calculations are used as a basis for qualitative arguments to explain the crack patterns which have been observed in GaN films on Si substrates.     

沉积粉煤灰的强度特性分析

结合靖远第二发电有限公司灰坝加高工程勘察、试验及计算分析专题研究,对靖远第二发电厂储灰场沉积粉煤灰进行了现场原位密度试验,室内颗粒分析、比重和三轴压缩试验。得到了沉积粉煤灰的基本物理指标、三轴试验摩尔-库仑强度指标、幂函数强度参数、E~μ模型参数、E~B模型参数和剑桥模型参数,分析该模型对沉积粉煤灰的适用性,并提出了参数选取方法。