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1.
Transient response of a spherical cavity with a partially sealed shell embedded in viscoelastic saturated soil 总被引：1，自引：0，他引：1
INTRODUCTION The propagation of stress-waves in an elasticmedium containing a cavity that are due to arbitrarydynamic loading applied on the cavity is of greatimportance in the fields of seismology, geophysicalprospecting, underground tunnels and deeply buriedpipelines, particularly as a model of an earthquakesource. Ben-Menahem and Cisternas (1963) devel-oped the theory for the dynamic response of an elastichalf-space medium to an explosion spherical cavity.Norwood and Miklowitz (… 相似文献
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INTRODUCTION Cracks are likely to occur on the interfaces of coated materials widely applied in engineering. It is important to detect the interface cracks by non-destructive means. Detecting the scattered waves induced by interfacial cracks by using ultrasonic technique can be considered as one of the most fea- sible methods. This paper focuses on the theoretical basis for the study of wave scattering induced by interfacial cracks. In the last two decades, there has been a large number o… 相似文献
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Dissolved oxygen sensor based on sol-gel matrix doped with tris(2,2’-bipyridine)ruthenium dichloride
To establish a immobilization method of oxygen sensitive dye, a dissolved oxygen sensor based on a sol-gel matrix doped with ruthenium complex ([Ru(bpy)3]2+) as the oxygen-sensitive material is reported. The results indicate that the I0 /I100 value of the [Ru(bpy)3]2+-doped in tetraethylorthosilane (TEOS) composite films are estimated to be 10.6, where I0 and I100 correspond to the detected fluorescence intensities in pure nitrogen saturated water and pure oxygen saturated water, respectively. Also, the Stern-Volmer plot shows a very good linearity at low dissolved oxygen concentrations. The response time of the composite films is 5 s upon switching from nitrogen saturated water to oxygen saturated water and 10 s from oxygen saturated water to nitrogen saturated water. The dissolved oxygen sensors based on the ruthenium complex/TEOS composite films exhibit greater sensitivity, stability and faster response time as compared to the existing ones. Furthermore, the thin films possess greatly minimized dye leaching effect. 相似文献
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INTRODUCTION The dynamic response of foundations resting onthe surface of a half space is of significant importancein soil-foundation interactions and machine founda-tion designs. Observation of earthquake damage in-dicated that the local soil properties, foundation ge-ometries, etc., play a central role in the dynamic be-havior of the soil-foundation system. Ever-increasing research has been devoted to theproblem of an elastic half space indented by a rigidfooting by employi… 相似文献
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The dynamic response of an infinite beam placed on a Pasternak foundation when the system was subjected to a moving load was investigated. We used the double Fourier transform and its inversion to solve the formulations of the problem. A closed form analytic solution of the beam was obtained by the theorem of residues. We selected a numerical example to illustrate the dynamic response of the beam on Pasternak and Winkler foundations, respectively. We discuss the effect of the moving load velocity on the dynamic displacement response of the beam. The maximum deflection of the beam increases slightly with increased load velocity but increases significantly with reduced shear modulus of subgrade at a given velocity. The maximum deflection of a beam resting on a Pasternak foundation is much smaller than that of a beam on a Winkler foundation. 相似文献
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INTRODUCTION Adequate information on dynamic soil proper-ties, especially dynamic shear modulus and dampingratio, is essential for accurate computations of groundresponse and soil-structure interaction problems.Many experimental investigations carried out onsandy soils through resonant column test or improvedcyclic triaxial test in early studies (Hardin and Richart1963; Hardin and Black, 1968; Drnevich and Richart,1970; Seed and Idriss, 1971; Kokusho, 1980) showedthat the small … 相似文献
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黄炳华 《杨凌职业技术学院学报》2003,2(1):32-35
在广东珠江三角洲地区，软弱土地基分布很广，土层厚，主要为淤泥或淤泥质粘土，是一种软塑到流塑状态的饱和软弱土，天然含水量大，压缩性高，抗剪强度及承载力很低，流变性大。在该地区修建水闸，地基处理是一个非常突出的问题，本文结合两个工程的地基处理方法，论述了深层搅拌在水闸工程中的运用。 相似文献
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论文主要分析了在“电路”与“信号与系统”课程中,相量法与傅里叶变换法两者之间的联系与区别。相量法和正弦稳态电路的分析、频率响应及零状态响应分析分别是各自课程中的重点及难点,对后续课程起着关键性的作用。文中通过实际例子详细分析了相量法与傅里叶变换法在求解频率响应方面的一致性,特别重点讨论了在求解系统零状态响应方面,学生容易误解而许多教科书也没有具体讲解到的两者之间的区别。 相似文献
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杨科峰 《杨凌职业技术学院学报》2009,8(3):1-3
现行建筑抗震设计规范采用标准贯入试验判别砂土液化,在实际工作中,愈是液化场地地层愈是松散、易塌孔,很难清底,应用标准贯人试验很难取得饱和砂土的贯入试验准确数据,通过有关理论的推导计算和实际互作的试验对比。认为应用园锥动力触探试验与标准贯入试验是有一定关联,对判别饱和砂土液化是具一定的参考意义。 相似文献
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秦玉伟 《渭南师范学院学报》2012,(2):52-54
针对傅里叶变换红外光谱仪的优点,测量红外探测器的光谱响应,设计一套新的光电检测系统.通过对测量所得红外干涉信号进行傅里叶变换,得到评判红外探测器性能重要技术指标的光谱响应度.系统在红外探测器光谱响应的测量上,继承了傅里叶变换红外光谱仪的功能和优点,实现了测量分辨率高、精度高和稳定性好. 相似文献
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The rapid urbanization and industrialization involve an unsustainable use of natural systems,leading to various problems in cities.The urban hydrological system experiences fluctuating amount of surfac... 相似文献
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KEVIN GARY 《Journal of Philosophy of Education》2019,53(3):477-490
Phenomenologist Jean‐Luc Marion describes our capacity for awe as an ability to recognise that certain phenomena are saturated. More than we constitute them with our categorical frames or organising objectives, the phenomena constitute us; their excess and givenness overwhelms our ability to fully grasp them. It is through this experience of awe and wonder, Marion suggests, that we are drawn into loving something or someone. In tension with this experience is the attempt (omnipresent in educational contexts) to organise and demarcate phenomenon (or fields of study) into a tidy list of coherent standards. This reductive move, while pedagogically pragmatic, risks masking the ‘exuberant splendor’ of saturated phenomenon, obscuring what initially drew teachers into their respective disciplines. What moves teachers (and students) to love a discipline, Marion suggests, is not standards, which are often instrumentally selected, but an experience of saturated phenomenon. More than standards, a teacher's deep and often secret hope is that her students love or at least appreciate her love for her subject. A teacher's love for her discipline, and her hope to impart it to her students, should stand in tension with the standards movement. 相似文献
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吴池胜 《中山大学学报论丛》1993,(1)
根据广州站的探测资料,用合成法分析了强风暴前期的中尺度环境场特征。结果表明,在行星边界层的较下部和700hPa高度附近,分别有一无辐散层,从地面往上至对流层上部,辐散和辐合依次相间出现,对整个气柱来说,辐散远大于辐合。风暴临近期,大气层结基本上可分为两类:一是所谓的“漏斗型”,另一是湿层深厚型(湿层向上伸达对流层的上部)。层结曲线上对流层中、下部的“暖盖”不是强风暴发生的必要条件,环境风的垂直切变也比较大。 相似文献
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文章利用C 语言编制了ANSYS到FLAC的接口程序,模拟了砂土粘聚力、内摩擦角、标贯数、桩长细比、动荷载等因素对液化砂土中桩的弦振效应的影响,得出了相关的规律曲线及各因素影响的敏感曲线.研究结果表明,桩基弦振效应随砂土粘聚力、内摩擦角、标贯数、动荷载频率、桩弹性模量的增加而减小,随桩长细比、动荷栽振幅增加而增大. 相似文献
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推导出在高次谐波干扰下,PARK矢量模平方函数的数学表达式,消除直接进行定子电流分析时基波频率对特征频率的影响。但是新增的频率成分很容易被直流分量、2f分量和4f分量淹没,对PARK矢量模平方函数进行傅立叶变换效果很差。采用多分辨率小波分析,对其各层系数进行分解与重构,其中第7层高频系数和第8层高频系数重构后的波形在发生故障时幅值明显大于无故障时的波形,对电机故障有很高的辨识度,是一种有效的方法。 相似文献
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康巨珍 《天津工程师范学院学报》2000,10(3):10-14
通过对付里叶变换积分性质的运用研究,指出付里叶变换微分性质运用时容易产生的错误;并提出确定冲激项存在与否的新途径,进而说明付里叶变换积分性质运用的广泛性,尤其对时间有限函数更为突出。 相似文献
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INTRODUCTION An important problem in foundation engineeringis the determination of the rate of settlement of a raftfoundation placed on a deep clay layer. Gibson andMcNamee (1957), and McNamee and Gibson (1960a;1960b) considered the problem of normal uniformloading applied to the surface of a half-space andshowed that one-dimensional theory gives a markedunderestimate of the rate of settlement. This theorycorresponds to the case of a perfectly flexible footing.However, it is often… 相似文献
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对春季不同覆盖层次下温度、植株干重的测定表明:不同覆盖层次下温度变化由高到低依次为:三层覆盖＞二层+草＞二层覆盖＞一层覆盖;光照强度强弱的变化为一层覆盖＞二层覆盖＞二层+草＞三层覆盖;随着覆盖层次的不断增加,植株高度不断增加,茎粗不断减小;植株干重的变化为在苗生长初期以二层覆盖和二层+草覆盖方式下最大,后期则以一层覆盖的植株干重最大;在叶绿素方面,蔬菜种类不同,其变化呈现各自不同的规律. 相似文献
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