灰色聚类的物元可拓法在煤与瓦斯突出预测中的应用研究

在对地质构造和煤与瓦斯突出关系研究的基础上,应用灰色关联方法对寺河矿煤与瓦斯突出的影响因素进行分析,确定研究区域煤与瓦斯突出的主要控制因素;根据煤与瓦斯突出主控因素分析结果,选取相应的煤与瓦斯突出预测指标,运用可拓聚类方法对这些指标进行综合分析,划分出地质构造带煤与瓦斯突出倾向性等级,进而预测地质构造单元的煤与瓦斯突出危险;应用建立的煤与瓦斯突出预测地质构造指标方法,对寺河矿西区X1301工作面进行煤与瓦斯突出危险性预测,划分出了严重突出危险区.     

改进AHP与Fuzzy综合评判的瓦斯突出危险性预测

为了能够准确有效的预测煤与瓦斯突出的危险性,提出将改进的层次分析(AHP)与Fuzzy综合评判理论相结合的方法,构建包含3个一级要素和9个二级要素的瓦斯突出危险性评价指标体系结构,采用"三标度法"对所建立体系结构中影响瓦斯突出的因素进行定性定量分析,根据层次总排序权值获取影响瓦斯突出的重要影响因素指标.采用Fuzzy综合评价实现对瓦斯突出危险性预测的单因素评价以及多级综合评判,结果表明,此方法提高运算复杂度的同时能够准确的预测,为煤与瓦斯突出预测和防治提供了科学的依据.     

基于可拓评价的无菌医疗器具生产环境安全评价与预警研究

将可拓评价方法用于无菌医疗器具生产环境安全评价与预测研究,建立了无菌医疗器具生产环境安全可拓物元评价模型.利用关联函数动态赋权法,改进了待评物元所属安全等级特征值的计算方法,使得判别更加准确.同时也对各单项指标进行了评价与预测,可为企业决策者提供更加有效的科学依据.     

层次分析、定性数据定量化在煤与瓦斯突出预测中的应用

以统计数据为依据,应用7±2心理极限概念和层次分析法确定各因素权重,采用定性数据定量化方法建立隶属度,采用二级模糊综合评判方法和“加权平均型”评判数学模型,建立了煤与瓦斯突出强度预测模糊综合评判方法,实现了定性问题的定量化分析.     

基于改进熵和灰关联分析的模糊物元分析模型及应用

借助改进熵权法对评价指标进行赋权,在灰关联分析和模糊物元分析理论的基础上,建立了改进熵和灰关联分析的模糊物元分析模型,根据灰色关联度的大小对评价对象进行排序,并将其应用到综合评价中,通过实例,说明此模型的合理性.     

基于KPCA-CS-ELM耦合模型的煤与瓦斯突出强度预测

为准确、快速地预测煤与瓦斯突出强度,实现预防煤与瓦斯突出,提出构建基于KPCA-CS-ELM的突出强度耦合预测模型.根据煤与瓦斯突出动力系统,确定影响突出的相关基础参数;采用核主成分分析(KPCA)提取出非相关特征参数作为主成分序列;利用布谷鸟搜索算法(CS)对极限学习机(ELM)的输入权值和隐含层偏差进行优化,寻得最优预测模型,并与CS-ELM、ELM、SVM和BP等模型预测结果进行对比分析.结果表明:基于KPCA-CS-ELM的突出强度预测模型能充分挖掘突出样本数据内部隐含规律,有效诠释突出强度与其影响因素间的非线性关系;模型对突出强度的预测与实例具有很好的一致性,运行时间为1.2463 s,较其他模型具有精准的判识度和较高的泛化能力.     

基于FOWA-模糊综合评价法的煤矿瓦斯爆炸危险性评价研究

为了对煤矿瓦斯爆炸危险性进行更科学地评价,依据三类危险源理论建立了包括防爆设备完好率、管理人员管理水平等15个评价指标的煤矿瓦斯爆炸危险性评价指标体系,并构建了基于FOWA模糊综合评价法的煤矿瓦斯爆炸危险性评价方法,同时以山西某矿掘进工作面为例进行实例验证.结果表明:方法的评价结果与实际结果相吻合,验证了评价体系的合理性及评价方法的可靠性.     

基于综合权重的理想模糊物元多属性决策法及应用

研究了属性指标具有不相容性和模糊性及其指标的权重完全未知的模糊多属性决策问题.分析了目前广泛采用的模糊物元分析法以及仅有主观赋权法或客观赋权法确定其指标权重的缺点.根据物元可拓理论和理想解法的思想,定义了理想模糊物元和负理想模糊物元的概念.利用兼顾主观偏好和客观信息的综合权重赋值法,提出了基于综合权重的理想模糊物元多属性决策方法.该法既能充分利用指标本身所包含的客观信息,又能充分发挥决策者的主观能动性.实例研究结果表明该法能反映出决策方案间的细微差别,能对决策方案的优劣做出更准确有效的评价.     

突出矿井瓦斯抽放限制影响因素的AHP-熵权法评价模型

为提高煤与瓦斯突出矿井瓦斯抽放效果,建立了3个一级指标、14个二级指标的突出矿井瓦斯抽放限制影响因素评价指标体系,利用AHP和熵权法分别确定指标因子主、客观权重.通过实地调研分析和反馈验证了AHP-熵权法的可行性和正确性,利用加权平均法确定评价模型的综合权重.研究表明:封孔方式、钻孔半径、抽放时间、煤体裂隙发育程度和抽放负压是目前影响煤矿瓦斯抽放效果的主控因素.     

水资源可再生能力综合评价的遗传加权物元模型

为了科学地计算水资源可再生能力评价指标的权重 ,使评价方法具有可操作性 ,采用主、客观相结合的赋权基点法 ,以全局收敛的格雷码加速遗传算法为工具来确定权重 ,并结合物元分析理论 ,建立了一种新的评价模型——遗传加权物元模型 .文中给出了该模型实施的详细步骤 ,对黄河流域 9个行政分区的水资源可再生能力进行了综合评价 ,取得了较好的效果 .     

Temporal and spatial variations of energy consumption in rural China

Presented in this paper is an overview of energy consumption in rural China in view of temporal and spatial variations. Characterized by steadily decreased proportion of biomass use and increased percentage of coal and electricity use, coal and biomass are still the major energy sources in rural areas, accounting for nearly 80% of the total rural energy consumption. Moreover, the energy consumption varies significantly across provinces both in total sum and by fuel types due to diversities of geographic features, economic development levels and local energy source availability. Three statistical groups are clustered associated with quantitative change and structural change, exhibiting evident transition from noncommercial energy pattern to commercial energy pattern. Much more work need to be done to cope with the forthcoming dramatic changes associated with booming rural economy and newly released policy from the points of both energy security and environmental pressure in China.     

Estimating diffusion-capacity parameters of a coal bed using the gas pressure measured in a hole and the solution of an inverse problem

A geomechanical model is proposed for gas emission from a coal bed with block structure. Some coefficient inverse problem is formulated for finding the initial gas content as well as the diffusion and mass transfer coefficients from the measured pressure in a well. The solvability of this problem is tested, and the additional data on the gas-kinetic characteristics of the coal bed are shown to be necessary for the inverse problem to have a unique solution.     

Large eddy simulation of non-premixed pulverized coal combustion in corner-fired furnace for various excess air ratios

Large-eddy simulations (LES) were carried out to study the effects of burning atmosphere on the coal combustion process in a corner-fired furnace. The LES for the turbulent gas was coupled with the discrete phase model (DPM) for coal particles trajectories and the non-premixed mixture fraction probability density function (MF-PDF) combustion model for pulverized coal combustion. The coal combustion processes, including the flame characteristics, burning coal behaviors and NO_x pollutant emissions, for different burning atmospheres are analyzed qualitatively and quantitatively. The heat and momentum transfer between burning coal and turbulent gas are greatly enhanced by the corner-fired flow. With a given particle size, the char particles present a similar distribution in the whole chamber. For a fuel-rich atmosphere, the concentration is obviously much higher and exhibits much higher spatial variability than the other two conditions. The coal combustion efficiency decreases in oxygen-rich and fuel-rich burning atmospheres, but the flame stability is more affected at the fuel-rich atmosphere by the lack of oxygen. NO pollutant is obviously reduced at the fuel-rich atmospheres, and the NO pollutant emissions are more affected by the reducing atmosphere than the low temperature. These findings may provide insight into strategies to design and monitor tangentially-fired pulverized coal boilers.     

Effect of gas seepage on stress-field redistribution in the vicinity of a hole

The effect of gas seepage on the stress-strain state of a coal seam is investigated. The problem of the degassing of coal seams with long holes is discussed. It is established that normal tensile stress components develop with the movement of gas in the vicinity of a hole. For certain ultimate tensile strengths of the coal, this reduces to failure of the walls of the hole, and to the development of dynamic phenomena.Translated from Teoreticheskaya i Prikladnaya Mekhanika, No. 18, pp. 115–119, 1987.     

Carbon emissions and resources use by Chinese economy 2007: A 135-sector inventory and input–output embodiment

A 135-sector inventory and embodiment analysis for carbon emissions and resources use by Chinese economy 2007 is presented in this paper by an ecological input–output modeling based on the physical entry scheme. Included emissions and resources belong to six categories as: (1) greenhouse gas (GHG) in terms of CO₂, CH₄, and N₂O; (2) energy in terms of coal, crude oil, natural gas, hydropower, nuclear power, and firewood; (3) water in terms of freshwater; (4) exergy in terms of coal, crude oil, natural gas, grain, bean, tuber, cotton, peanut, rapeseed, sesame, jute, sugarcane, sugar beet, tobacco, silkworm feed, tea, fruits, vegetables, wood, bamboo, pulp, meat, egg, milk, wool, aquatic products, iron ore, copper ore, bauxite, lead ore, zinc ore, pyrite, phosphorite, gypsum, cement, nuclear fuel, and hydropower; (5) and (6) solar and cosmic emergies in terms of sunlight, wind power, deep earth heat, chemical power of rain, geopotential power of rain, chemical power of stream, geopotential power of stream, wave power, geothermal power, tide power, topsoil loss, coal, crude oil, natural gas, ferrous metal ore, non-ferrous metal ore, non-metal ore, cement, and nuclear fuel. Accounted based on the embodied intensities are carbon emissions and resources use embodied in the final use as rural consumption, urban consumption, government consumption, gross fixed capital formation, change in inventories, and export, as well as in the international trade balance. The resulted database is basic to environmental account of carbon emissions and resources use at various levels.     

凝析油-气在存在裂缝的双渗介质中渗流的变产量数学模型及其应用

当凝析气藏压力低于露点压力时,有凝析油析出,致使井底附近阻力变大,影响凝析气的采出量,反凝析现象带来了一些特殊的经济问题.选择合理的开发方式,提高凝析气的采收率,成为了当前工作中迫切需要解决的难题.为了控制合理的井底流压常会引起产量的改变.主要针对凝析气在存在裂缝的双渗气藏中的渗流问题,建立气井变产量生产新模型并进行求解,同时选择相关合理参数绘制了试井理论图版,根据试井理论图版利用试井测试数据进行解释,可以得到相应动态参数为气田开发预案提供相应的理论依据.     

Gas emission into the excavated space during the mining of coal seams

Using the method of successive approximations we construct a numerical/analytic solution, of the nonlinear filtration equation that describes the process of gas emission from a coal seam that is being mined. It is assumed that in the opening and excavation of a deposit a finite filtration region forms near the exposed coal face, and that the gas emission process is accompanied by the appearance of an unknown moving boundary. It is established that this boundary moves slowly toward the end of the filtration region and the determination of its location must be taken into account in computing the load on the drift from the gas factor. Translated fromTeoreticheskaya i Prikladnaya Mekhanika, No. 23, 1992, pp. 112–115.     

Energy spectrum and the absolute flux of various celestial X-ray sources

The results on the flux of low energy X-rays in the range 2–18 Kev from Sco-X1, Tau-X1 and Cen-X2 celestial sources observed during two rocket flights, flown from the Thumba Equatorial Rocket Launching Station (TERLS), Trivandrum, India, are presented. The absolute flux and the energy spectrum obtained for these sources are compared with other similar observations. The results indicate a long-term exponential decrease in the energy flux of X-rays from Sco-X1 over the period 1965–1968. The X-ray source Cen-X2, which showed a remarkable outburst of X-rays in April 1967, had ceased to be active after May 1967. We present here the first evidence of the rediscovery of the low energy, X-ray flux from Cen-X2 since May 1967. These short-lived X-ray out-bursts may be attributed to a shock wave from the nova outburst expanding into the circumstellar medium.