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采用高密度电阻率法对某一煤矿采空区进行了探测。利用地电影像资料对比分析了高密度电法对地下采空区的探测效果。结果显示该方法具有断面异常形态清晰、探测精度高等优点。 相似文献
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郭利 《西安文理学院学报》2014,(1):86-88,92
利用有限元分析的方法对检定车流速仪测杆部件的横截面形状进行优化设计,结果表明,相同速度下,测杆在水中行进时,水滴形流线型分水板抗弯能力强于矩形、圆形以及前流线型的分水板,且其受到水的阻力小于其他两种截面.确认使用水滴形流线型横截面测杆后,对测杆部件的整体结构进行了设计.试验表明,设计能良好满足所需要的精度测量. 相似文献
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1 Introduction Incommunicationsystemapplications ,microstripantennashaveattractedmuchinterestduetotheirlightweightandlowcost.Possibledesignsfordual frequencymicrostripantennasincludedual modedual frequencypatchantennas,multi patchstructuresandreactively loadedpatchantennas,etc[1,5] .Theor thogonal modedual frequencypatchantennasprovidenosimilarradiatingpatternsofthetwooperatingfre quencies .Themulti patchstructureaddstothecom plexityinboththeoreticalanalysisandmanufacturing .Loadingthemicro… 相似文献
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鉴于国家对能源的大量需求,赵固二矿在原设计的分层开采基础上,应用一次采全高的高产高效工作面,工作面的上下顺槽为矩形断面,设计超前支护,上下端头安设液压支架。工作面设备全部采用国产化设备,这些工艺及设备的应用,保障了煤矿安全、高产高效、自动化生产。 相似文献
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文章以矩形螺线管轴线上的磁场分布特点为基础 ,将螺线管的对称截面按矩形进行分割 ,分析得出螺线管对称轴上磁场分布的一般规律。 相似文献
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《天津大学学报(英文版)》2015,(3)
In order to improve the seismic performance, deformation ability and ultimate load-carrying capacity of columns with rectangular cross section, engineered cementitious composite(ECC) is introduced to partially substitute concrete in the edge zone of reinforced concrete columns and form reinforced ECC/concrete composite columns.Firstly, based on the assumption of plane remaining plane and the simplified constitutive models, the calculation method of the load-carrying capacity of reinforced ECC/concrete columns is proposed. The stress and strain distributions and crack propagation of the composite columns in different states of eccentric compressive loading are analyzed. Then, nonlinear finite element analysis is conducted to study the mechanical performance of reinforced ECC/concrete composite columns with rectangular cross section. It is found that the simulation results are in good agreement with the theoretical results, indicating that the proposed method for calculating the load-carrying capacity of concrete/ECC composite columns is valid. Finally, based on the proposed method, the effects of ECC thickness, compressive strength of concrete and longitudinal reinforcement ratio on the mechanical performance of reinforced ECC/ concrete composite columns are analyzed. Calculation results indicate that increasing the thickness of ECC layer or longitudinal reinforcement ratio can effectively increase the ultimate load-carrying capacity of the composite column with both small and large eccentricity, but increasing the strength of concrete can only increase the ultimate loadcarrying capacity of the composite column with small eccentricity. 相似文献
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研究两种规则三维物体（如极长的长方体和圆柱体）横截面的温度分布,利用复势分析法得出这两种平面温度场的复势,并且数值模拟出温度的分布图像。 相似文献
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采用有限元实体单元,分析了薄壁截面悬臂梁在双力矩作用下的截面内变形。数值分析表明：开口截面在双力矩的作用下,截面以旋转变形为主,截面内的相对变形很小,与符拉索夫薄壁梁理论的“刚周边假定”吻合,符拉索夫的理论结果与实验结果符合很好;闭口截面在双力矩的作用下,以截面内的相对变形为主,截面的旋转较小,薄壁梁理论的“刚周边”假定与数值分析结果有出入。 相似文献
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让建筑学专业的学生掌握RC梁由拱作用和梁作用共同形成的原理是有难度的。在“建筑结构”课程教学中,为了让学生较好地理解RC梁的正截面破坏问题,可假设从单筋矩形截面梁中分离出一个混凝土受压拱身与钢筋拉杆形成的组合拱,然后借助拱机理来讨论截面产生抗弯承载力的原理及三种正截面破坏类型的区别,对帮助学生加深理解具有一定的效果。 相似文献
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用德国莱宝教学仪器公司提供的风洞演示实验仪，学生自主设计实验，观察和研究空气阻力与风速、物体横截面积、物体形状的关系以及飞行原理等。 相似文献
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A practical method for computing the one-way rectangular orthotropicplate(isotropic plate as a special case)is suggested in this paper.The supported condi-tions in two opposite edges may be simply supported,continuous or supportednonsymmetrically and the other two opposite edges are slide-supported or free.A series ofsimplified formulas are given for calculating the bending moments along the cross section(loaded section),in which the acting point of the concentrated load or the center of a rec-tangular uniform load is located.The valid range and accuracy of these formulas were stud-ied and the approximate results were examined and compared extensively with those by thetriangular series solution or finite element method. 相似文献
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Word frequency and readability: Predicting the text‐level readability with a lexical‐level attribute 
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下载免费PDF全文 Assessment of text readability is important for assigning texts at the appropriate level to readers at different proficiency levels. The present research approached readability assessment from the lexical perspective of word frequencies derived from corpora assumed to reflect typical language experience. Three studies were conducted to test how the word‐level feature of word frequency can be aggregated to characterise text‐level readability. The results show that an effective use of word frequency for text readability assessment should take a range of characteristics of the distribution of words frequencies into account. For characterizing text readability, taking into account the standard deviation in addition to the mean word frequencies already significantly increases results. The best results are obtained using the mean frequencies of the words in language frequency bands or in bands obtained by agglomerative clustering of the word frequencies in the documents – though a comparison of within‐corpus and cross‐corpus results shows the limited generalizability of using high numbers of fine‐grained frequency bands. Overall, the study advances our understanding of the relationship between word frequency and text readability and provides concrete options for more effectively making use of lexical frequency information in practice. 相似文献
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该研究考察输入频次类型对中国大学生英语语义韵学习的影响,并分别考察该频次效应与外显学习和内隐学习的关系。北京某大学69名本科生参加了不同频次（高语类或高语符）输入的语义韵学习对比实验,测量工具包括短语判断测试、问卷和访谈等。结果显示,高语符频次比高语类频次在一定程度上更能促进英语语义韵的学习,且该频次效应对内隐学习影响较大。研究发现语类频次对能产性的促进作用要以一定量的语符频次为基础。 相似文献
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Luquire et al.'s impedance change model of a rectangular cross section probe coil above a structure with an arbitrary number of parallel layers was used to study the principle of measuring thicknesses of multi-layered structures in terms of eddy current testing voltage measurements. An experimental system for multi-layered thickness measurement was developed and several fitting models to formulate the relationships between detected impedance/voltage measurements and thickness are put forward using least square method. The determination of multi-layered thicknesses was investigated after inversing the voltage outputs of the detecting system. The best fitting and inversion models are presented. 相似文献
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从实测水文资料出发,应用石角、三水水文站长期的月平均水位、流量及含沙量资料,以及北江下游2000年洪、枯两季山塘断面、烂柴洲断面、岐洲断面及芦苞洲断面的连续7个小时的水位、流速、含沙量及大断面资料等,对北江下游河段的水文泥沙特征进行了详尽的分析。 相似文献