采动和强承压水作用下大倾角断层防水煤柱宽度分析

本项目以断裂上盘煤层为对象,以大倾角正断层不透水煤柱为研究对象,通过数值模拟与现场测试相结合的手段,考虑煤层走向与煤层底板走向的组合效应,构建煤柱开采影响区、弹性核区与断裂破裂区煤柱宽度的计算模型,并在煤层走向与底板走向相结合的条件下,深入剖析煤柱在煤层走向与底板抗水失稳破坏的受力机理,进而揭示不透水煤柱的适宜透水煤柱宽度的影响机理。结果表明,在确定断层不透水煤柱的宽度时,应同时考虑采动压力与断裂的共同作用;在此基础上,结合煤层底板是否能够承受承压水的冲击,提出大倾角正断层不透水煤(岩)柱的合理宽度计算方法。经实际应用证明,该方案具有较好的留设宽度,也有有较好的经济效益。

基于脉冲宽度分析的实时数字堆积排除方法研究

高计数率下的核能谱获取中,随机脉冲的堆积效应造成获取到的核能谱分辨率变差。为了有效抑制脉冲堆积对γ谱仪分辨率的不利影响,基于高速全波形数字化采样技术,文中提出了脉冲宽度分析方法应用于高计数率下的核脉冲实时堆积判别和拒绝。采用仿核脉冲信号源论证了该堆积拒绝方法的可行性,也使用了Na I闪烁体探测器对137Cs和60Co两种放射源进行实验测试。结果表明:该方法可以有效实时识别出脉冲后沿和前沿堆积情况,在高计数率下可以有效改善数字γ谱仪分辨率。

钢筋混凝土结构用分布裂缝模式求裂缝开展宽度的数值分析

采用“最大拉应力单元开裂”准则 ,完善了平面问题钢筋混凝土非线性有限元程序 ,改进了程序非线性分析迭代流程 ,能模拟实际结构开裂情况 ,找出裂缝发生位置 。

机械活化黄铁矿物理性能和表面结构变化的表征

利用SEM、粒度分析、X射线衍射谱线宽度分析、XPS等现代分析测试手段对机械活化黄铁矿物理性能和表面结构进行了研究。实验表明,机械活化黄铁矿可导致表面吉布斯自由能的增加、机械储能的增加和极少量新物质的生成。

Static and Dynamic Analyses of Long-Span Spatial Steel-Cable-Membrane Hybrid Structures

With the increment of the complexity of structural systems and the span of spatial structures, the interactions between parts of the structures, especially between some flexible substructures, become too complex to be analyzed clearly. In this paper, taking an actual gymnasium of a long-span spatial steel-cable-membrane hybrid structure as the calculation model, the static and dynamic analyses of the hybrid structures are performed by employing the global analysis of the whole hybrid structure and the substructural analysis of the truss arch substructure, the cable-membrane substructure, etc. In addition, the comparison of stresses and displacements of structural members in the global and substructural analyses is made. The numerical results show that serious errors exist in the substructural analysis of the hybrid structure, and the global analysis is necessary for the hybrid structure under the excitation of static loads and seismic loads.

Multi-fractal Behaviors of Relative Humidity over China

The multi-fractal ity over China are studied behaviors of relative humid using the multi-fractal de trended fluctuation analysis （DFA） method. Three multi fractal parameters （the spectrum width Aa, the asymmetry Aaas, and the long-range correlation exponent a0） of the singularity spectrum are introduced to quantify the multi-fractal behaviors. The results show that multi-frac tality exists in daily humidity records over most stations in China and is mainly due to the broad distribution of the probability density of the sequence values. Strong multi fractal behaviors over some stations in the Yunnan, Guangdong, and Inner Mongolia provinces are obvious. These behaviors are mainly caused by different long range correlations between large and small fluctuations. The asymmetry of the singularity of relative humidity records is weak, except for a small number of stations in the far east and west of China, where the singularity spec trum is left-skewed. Finally, the long-range correlations in North China are stronger than those in South China, which indicates better predictability in North China. By studying the parameters of the multi-fractal spectrum, various data of long-range power law correlations of the relative humidity records are obtained, which may pro vide theoretical support for climate prediction.

P25 Scoring Method for the Assessment of R/C Buildings

An effective rapid assessment technique, called ＂P25 Scoring Method＂, has been developed and tested on 26 different case studies recently, in order to predict the collapse vulnerability of the R/C buildings. After a short description of the approach, the study presents the sensitivity study of the method to the selected structural parameters by considering incremental deviation of the final scores from the base model. Further, the methodology was applied to an additional 100 damaged buildings in order to check the reliability of the method and some necessary modifications have been applied to the algorithm after considering this larger database. The evaluation of the results has been interpreted as a beneficial guidance for local authorities. The risk bands are defined according to the final scores and the effect of changing the band-width has also been studied through a safe but an economical procedure. A satisfactory correlation of the method with real damage states is obtained and a ready-to-use methodology has been introduced for future studies.

Potential Impacts of Various Land Use Forms on Land Degradation in Arid Regions （Case Study： Kuwait）

During the last 20 years, land use in Kuwait was remarkably changed in various forms. Such changes resulted in positively constructive, as well as, adversely destructive impacts on the local environment and ecology. In 1993-1994, a buffer zone of 15 km wide and more than 200 km long was established between Iraq and Kuwait. This allowed the restoration of biodiversity, enhancement of ecological conditions and stabilization of fragile soils. In 1991, long bund walls were constructed along the Saudi-Kuwaiti borders by Saudi Arabia and in 1993-1994, a ground trench was dug along the Iraqi-Kuwaiti borders by Kuwait. Bund walls are piles of excavated soils, 2-3 m high, 3-5 m wide and several tens of kilometers length. Constructing 1 km length of a bund wall required 2,500-3,000 m3 （1,000 m length x 5 m average width x 0.5 m depth） amount of soil, which disturbed a groundcover strip of an average area of 10,000 m2 （1,000 m length x 10 m average width）. Border trenches are ground hollows 2-3 m deep, 3-5 m wide and 220 km long. The amount of excavated soil from digging 1 km long trench ranged from 6,000-8,000 m3. Field work indicated that 1 km long of trench had disturbed a groundcover of an average area of 12,000 m2 （1,000 m length ~ 12 m average width）. Such man-induced land features are closely related to land degradation processes, as they were of adverse environmental impacts on soil, surface hydrologic conditions and natural vegetation. The main objective of this study is to assess the immediate and long term impacts of the introduced land use forms in selected areas in Kuwait, such as Wadi AI Batin （Western part of Kuwait）. To achieve such an objective, intensive field program was designed and implemented and the collected data and available information were analyzed and interpreted.

脉冲激光峰值功率测试方法

为解决生产过程中所用脉冲激光光源输出峰值功率的测试难题，并保障其量值准确可靠，实现测试结果可溯源性，以激光能量计作为量值传递标准，以脉冲激光波形半宽度分析法为基本原理，提出了以组合衰减片法实现脉冲激光峰值功率测试的新思路。

Analysis of 2D Flow and Heat Transfer Modeling in Fracture of Porous Media

Heat and mass transfer between porous media and fluid is a complex coupling process, which is widely used in various fields of engineering applications, especially for natural and artificial fractures in oil and gas extraction. In this study, a new method is proposed to deal with the flow and heat transfer problem of steady flow in a fracture. The fluid flow in a fracture was described using the same method as Mohais, who considered a fracture as a channel with porous wall, and the perturbation method was used to solve the mathematical model. Unlike previous studies, the shear jump boundary condition proposed by Ochoa-Tapia and Whitaker was used at the interface between the fluid and porous media. The main methods were perturbation analysis and the application of shear jump boundary conditions. The influence of permeability, channel width, shear jump degree and effective dynamic viscosity on the flow and heat transfer in the channel was studied by analysing the analytical solution. The distribution of axial velocity in the channel with the change of the typical parameters and the sensitivity of the heat transfer was obtained.

Determination of the cluster spectroscopic factor of the 10.3 MeV state in ^(12)Be

From an inelastic excitation and breakup experiment with a12Be beam at 29 MeV/u,a large4He+8He cluster decay width of 1.1(2)MeV is determined for a state at an excitation energy of 10.3 MeV and with a spin parity of 0+.By using the R-matrix analysis,a cluster spectroscopic factor of 0.53(10)is extracted from the cluster partial width,providing a strong support for the clustering structure in12Be.A specially designed zero-degree telescope played an essential role in the present experiment and has been demonstrated to be a promising tool in future studies of the molecular-like resonances near the cluster separation threshold.

Effects of overburden, rock strength and pillar width on the safety of a three-parallel-hole tunnel

During the excavation of three-parallel-hole tunnel, the tunnel might collapse due to over-stress as a result of inadequate rock pillar width. Treating the rock overburden depth, rock strength, and rock pillar width as variables, a series of 3D numerical analysis was carried out to examine the effect of each variable on the safety of the tunnel, in particular the rock pillar. A stress strength ratio (SSR) was used to define whether the safety of the rock pillar was exceeded. A simple design chart for the case of three-parallel-hole tunnel, which took into account the influence of overburden depth, rock pillar width, and rock strength, was also proposed for used in the preliminary design stage.

Occurrence data may provide unreliable thermal preferences and breadth of species

Accurate information on the thermal preference and specialization of species is needed to understand and predict spe- cies geographical range size and vulnerability to climate change. Here we estimate the position and breadth of species within thermal gradients based on the shape of the response curve of species abundance to temperature. The objective of the study is to compare the measurements of this approach based on abundance data with those of the classical approach using species＇ occur- rence data. The relationship between species＇ relative abundance and minimum winter temperature of 106 bird species wintering in the Iberian Peninsula is modeled at 100 Km2 resolution with quadratic logistic regressions. From these models we calculated the preferred temperature of species as the temperature at which the abundance is maximized, and the thermal breadth of species as the relative area under the temperature-abundance curve. We also estimated the thermal preferences and breadth of species as the average temperature and temperature range of the UTM cells in which the species are present. The abundance-temperature response curves reveal that birds prefer higher temperatures to overwinter, and are more thermally selective, than is measured by the classical approach. Moreover, response curves detect a higher inter-specific variability in both thermal preferences and ther- mal breadth of species. As occurrence data gives the same weight to cells with one or many individuals, the average temperature of the cells in which the species is present roughly reflects the average temperature in the region of study and not the environ- mental preferences of species .

Line-profile analysis of excitation spectroscopy in the even 4p^5(~2P_(1/2))nl′ [K′]_J(l′=1,3) autoionizing resonances of Kr

The even-parity autoionizing resonance series 4p^5np＇ [3/2] 1,2, [ 1/2] 1, and 4p^2nf＇ [5/213 of krytpon have been investigated by laser excitation from the two metastable states 4p55s [3/2]2 and 4p^55s＇ [1/2]0 in the photon energy region of 2900（P40000 cm^-1 at experimental bandwidth of -0.1 cm-1. The excitation spectra of the even-parity autoionizing resonance series, most of which are experimentally studied for the first time in this work, show typical asymmetric line shapes. Complementary information on level energies, quantum defects, line profile indices and resonance widths, resonance lifetimes and reduced widths of the auto- ionizing resonances are derived by Fano-type line-shape analyses of the experimental results. Results from this work indicate that the line profile index （q） and the resonance width （F） are approximately proportional to the effective principal quantum number （n＊）; the line separation of the 4p^5np＇ autoionizing resonances is also in good agreement with theoretical model