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1.
The macromolecular structures of coal samples collected from Yutianbao, Nantong and Qingnian coal mines in Sichuan were studied and a model of structure for these coals was set up. On the basis of above mentioned work,experimental studies and theoretical analyses were made to investigate the characteristics of coal polarization in applied electric field. The results indicate that the rotation polarzation and the space polarization are the essential reason for the attenuation of electric current through coal samples,and that the space polarization is the main form of coal polarization.  相似文献   

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Based upon the anisotropy of electric polarization,the nonolinear oscillation equation of the ellipsoid in electric field is constructed by considering the rotative moment between electric field and the induced dipole moment on metallic ellipsoid of field intensity gauge. The oscillation period relative to the amplitude and electric intensity is calculated.An expression of exact computation to measure the electric field intensity is achieved.The impact of the amplitude parameter upon the experiment calculation is analyzed and the method to determine the amplitude is contributed.A contrast to the computed resuls by means of linear oscillation is undertaken to show the raising effect to the calculation precision by considering nonlinearity in oscillation.  相似文献   

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The semi-empirical Kozeny-Carman (KC) equation,the most well-known permeability-porosity relation, is widely used in the field of seepage flow in porous media. However, the physical mechanisms behind the empirical KC constant are not clear, and the KC constant has not been proved to be a constant. The fractal scaling laws of pores have been extensively found in porous media. Therefore, the effective permeability of homogenous porous media is presented and the analytical expression of KC constant is derived based on the fractal characteristics of porous media and the microcosmic geometrical model. The results indicate that the fractal analytical expression of KC constant depends on the micro-structure of porous media. As a function of porosity and fractal dimensions, KC constant increases with the increase of porosity.  相似文献   

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安太堡露天煤矿排土场景观结构及其分形研究   总被引:5,自引:0,他引:5  
将平朔安太堡露天煤矿复垦区的5个排土场按照植被覆盖和地形划分为8个基本景观类型,包括耕地、草地、草灌混交、灌木混交、乔草混交、乔灌混交、新造复垦地和退化地,总计496个斑块。利用3S技术和分形理论对景观结构进行了分析,并讨论了景观特性及其变化的分形性质。结果表明:分维数的大小反映了景观斑块面积、斑块数量和平均斑块面积等因素的相互作用,反映了排土场内景观斑块的不规则程度和复杂程度;乔灌混交地和灌木混交地保持着较高的分维数,新造复垦地和草地的分维数较低,其它景观类型的分维数则差别不大;植被景观受多种因子的影响,在南排土场、西排土场受地表物质组成和地形的影响为主,其多样性指数较高,在内排土场、西排扩大区受植被类型的影响为主;草灌混交地的景观多样性远高于其它现有的复垦植被区,但其景观优势度则保持在较低水平上。南排、西排及西排扩大区的景观过程以控制水土流失、增加植被覆盖为主,内排则着重发展兼顾经济、生态和社会多种效益的生态农业和高效农业。  相似文献   

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It is very important to mine safe exploitation, gas drawing and predict of coal and gas outburst that adsorption characteristics of coal to gas in geophysical field are studied. Adsorption and desorption characteristics of coal to gas in geophysical field have been reviewed in detail, then it is obtained that adsorption characteristics of coal to gas in electromagnetic field should be further studied . Adsorption and desorption characteristics of coal to methane in alternating electric field (AEF) have been studied mainly. Adsorption characteristics of three coal samples in AEF have been studied by means of Volume Method. The result shows that chemical properties and matter constituent of coal surface are no changed , adsorption and desorption of the coal samples in AEF well accord with Langmuir equation and two constants empirical formula, and because coal potential energy is increased and coal temperature is raised caused by Joule heat effect , adsorption ability of coal is decreased, and the desorption process is slowed down in AEF.  相似文献   

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The solution of polarization field strength in ellipsoid and a homogeneous dielectric in condition of a constant external field is obtained with strict derivation and ellipsoidal coordinate. The conclusion that some textbooks given: the direction of polarization field strength with the direction of external field holds strict anti-parallel must be supplemented with additive certain conditions, otherwise it will not be correct. By means of the latticework and the step change calculation, the angle value of polarization vector with the external field is calculated and the changing situation about the angle value with the change of three half axes of ellipsoid is analysied.  相似文献   

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The authors discusss exciton energies in a thin film with d thickness and influence of the edge polarization upon the excitons.The polarization is described as interaction between electron(hole) and its image charge.It is found that the interaction decreases the exciton energies to some extent and the influence of the interaction upon the films possessing different dielectric constants and with different thickness are different.  相似文献   

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以X波段双偏振雷达的多种参数为依据,综合使用雷达及相关雨量站的降水观测资料,从基本组成及雷达工作方式2 个方面简述了X波段双偏振多普勒雷达,并针对2014 年8 月9 日内蒙古地区的一次对流性降水天气过程,着重分析X波段双偏振多普勒雷达降水观测。结果表明:(1)在流性雷暴云降水过程中,大部分冰晶类将会在6~8 km融化为小雨滴,或以冻滴的形式存在;(2)强雷暴云天气发生时,在强雷暴云中上层的存在大部分的小粒子,并无大量的水成物粒子存在。该研究不仅能够探索雷达对降水进行定量估测的能力,还能够通过提升X波段双偏振雷达降水观测的适用性,以期为今后X波段双偏振多普勒雷达在降水观测中的应用提出一定的参考依据。  相似文献   

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To avoid equilibrium potential shifts in polarization curve test, based on anodic polarization current method, the critical polarization current density of steel corrosion was given as well as the corresponding empirical formula of corrosion current density. Reasonable explanation to equilibrium potential shifts was given by studying polarization curves characteristic of rebar in concrete before and after corrosion. The results show that anodic polarization current method can effectively distinguish steel corrosion, and the critical polarization current density is 0.2 μA/cm 2.  相似文献   

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The circular polarization microstrip antenna is one kind of low cut plane antenna element . Researching circular polarization microstrip antenna property is very important in antenna design. And how to find the feed place is the key to design. Researching makes a detailedly analysing and expounding of the pentagon circular polarization microstrip antenna in view of the single ended side. The microstrip antenna realization means is introduced. The way to analyze polygon microstrip antennal is given, which is named finite cell. By adjusting the 5.6 GHz pentagon circular polarization microstrip antenna, we give out the circular polarization microstrip antenna design processing. The feed place is found with the right means. Adopting HFSS software to optimize the design , and carries on imitation , give out the right imitation result .  相似文献   

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The measurement of in-site crustal stresses are carried out in Yan Shi Tai coal mine.The outburst-proneness of 6# coal seam are studied with five indexes. Based on the strength testing of coal,the strength criterion is set up. The energy criterion is put forward in the light of engineering practice.According to the "three criteria" mechanical model,the prediction of danger zone of coal burst of 6# coal seam in this mine is carried out.  相似文献   

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The paper introduces the application of CAN bus in the Hybrid Electric Vehicle, studies the CAN bus technique and the design based on the node of CAN bus, and provides a network topology mode. The theories foundation and basis for new generation automotive are provided, which are combined to introduce the hardware constitutes and software method for the node of CAN bus.  相似文献   

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The bar and the cloud microcosmic appearance character of the electric erosion is described in this paper.The electric erosion mechanism of the gear surface has been set forth by setting up the model of electric erosion of the discharge not contacted and the model of electric erosion of discharge contacted. The electric erosion of the discharge not contacted would be taken place when the voltage is stronger and the lubricating oil film formed better between the space of the gear surface. The electric erosion of the discharge contacted would be taken place when the voltage is lower and the lubricating oil film formed not better between the space of the gear surface. The failure of the gear is accelerated by the action of the electric erosion and the friction wear together.  相似文献   

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The amorphous structure characteristics of coal and their variation regularity are discussed.The pore structure features and models of coal have been reviewed in detail.  相似文献   

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Generally there have a number of bad data in the electric load data and it affects the precision of load forecasting,so it is necessary for extracting the feature mode of days load data,then cleaning the load data before it is used to forecasting electric load or performing power system analysis.Inspired by soft clustering thought,a intelligent feature mode of days load data extracting method is proposed based on the mutual offset of fuzzy c-means clustering arithmetic and Kohonen self organization feature map neural network.With the merits of not only high extracting precision and convergent speed but also dynamic calculation capability,the method proposed can supply load forecasting or system analysis procedure with due data.Test results using actual data of Chengqu power supply bureau in Chongqing demonstrate the effectivity and feasibility of the method.  相似文献   

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