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为了研究中横隔梁对T形梁桥荷载横向分布的影响,制作了2个T形钢梁桥实验模型,每个模型由5片T梁肋组成,其中一个有中横隔梁,一个无中横隔梁.用Midas/civil有限元分析软件建立了T形梁桥实验模型,进行了理论计算与分析,并与实测值进行了比较.结果表明,有中横隔梁的T形梁桥模型的整体刚度相对较大,各单片梁肋间的传力较好,故各梁肋的荷载横向分布系数接近直线分布;无中横隔梁T形梁桥由于仅有桥面板传递剪切变形,在对称及偏心荷载作用下,集中荷载作用梁肋的应变与挠度均较大,荷载横向分布呈不均匀现象. 相似文献
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基于逐层传热计算方法,计算高真空多层绝热传热量,进而确定高真空多层绝热综合导热系数.结果表明,外界环境温度越高,升高相同温度,高真空多层绝热传热量增加越多,综合导热系数增加越多;基于综合导热系数,进行高真空多层绝热温度场数值模拟研究.结果表明,越靠近冷端,绝热层中温度变化越大,温度降低越明显;越靠近热端,绝热层中温度变化越小,温度升高越微弱. 相似文献
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本文研究了各种型式肋片在辐射—对流—导热联合作用和变热特性参数条件下,稳态和非稳态传热时的通用数学物理模型和数值计算方法．为编制通用程序奠定了基础。 相似文献
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《中学生数理化(高中版)》2015,(3)
<正>比热容是在学生学习了热传递、热量知识的基础上,进一步研究物体温度升高时吸收热量多少与哪些因素有关后建立的概念,它是本章的重点知识,也是比较抽象、学生感到较难的一节.在中考中往往结合热量问题考查,其中两物体之间的热量传递问题学生最为头疼.究其原因,我认为有这样几点:一、热量传递问题牵扯的物体较多,过程较为复杂.二、概念认识不清、不透彻,如物体之间热量传递的实质是温度差;传递方向是从高温物体传向低温物体,或从高温部分传向低温部分等. 相似文献
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本文根据边界层方程和导热方程,分析了肋表面的局部传热特性。结果表明：在自然对流和强迫对流两种情况下,竖直布置的矩形直肋表面的局部对流换热系数分布是不均匀的。研究结果将有助于对肋片表面传热机理的认识。 相似文献
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通过对热量从煤炭传递到原油全过程利用率的计算,对影响热量利用率的主要原因和如何提高热量利用率进行了分析和探讨。 相似文献
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新编初中物理第二册热学内容中,热量和比热是两个十分重要的概念。知道热量,结合比热的计算,可以知道温度的变化;结合燃烧值的计算,可以知道物体燃烧时放出的热量;结合热功当量的计算,可以知道热量相当于多少机械功。比热则是热量计算公式 相似文献
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给出了在用电热法测液体的比热容实验中,采用交换测量方法的一种数据处理方法.这种方法也适于其它一些物理实验数据的处理,并能够提高实验的准确度. 相似文献
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本文作者在热学教学工作中,在强化能力培养,优化教学内容、改革教学方法等方面,进行了某些实践的探索及尝试。 相似文献
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Compression and expansion of a working gas due to the pressure oscillation of an oscillating flow can lead to a temperature variation of the working gas, which will affect the heat transfer in the oscillating flow. This study focuses on the impact of the compression-expansion effect, indicated by the pressure ratio, on the heat transfer in a finned heat exchanger under practical operating conditions of the ambient-temperature heat exchangers in Stirling-type pulse tube refrigerators. The experimental results summarized as the Nusselt number are presented for analysis. An increase in the pressure ratio can result in a marked rise in the Nusselt number, which indicates that the compression-expansion effect should be considered in characterizing the heat transfer of the oscillating flow, especially in the cases with a higher Valensi number and a lower maximum Reynolds number. 相似文献
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Zhou JiangangChen Yinchun 《大连大学学报》1994,(1)
经典统计理论应用到热辐射时发现理论与实际不符合。为了克服这个困难,普朗克(Planck)在1900年引入了量子假设。本文较详细地讨论了经典统计理论如何与实际不符及普朗克又如何克服了这个困难。 相似文献
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INTRODUCTION Cross flow and heat transfer were widely found in oil production and chemical facilities.A detailed study of the hydrodynamic characteristics and heat transfer of cross flow is necessary for optimal design of the system and the development of new measuring techniques.Studies on the heat transfer in sin-gle-phase liquid cross flow were carried out in the past decades.Air or water was often chosen as the working fluid,in these studies commonly focused on fluids flowing across r… 相似文献
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The physics and chemistry education literature has grappled with an appropriate definition for the concept of heat for the past four decades. Most of the literature promotes the view that heat is ‘energy in transit’ or ‘involves the transfer of energy’ between the system and surroundings because of a difference in temperature. Given that many undergraduate students are not learning the concept of heat in physics and chemistry alone, the goal of this investigation is to explore the conceptions of heat as presented in textbooks from across the science disciplines. An analysis of the definitions of heat from physics, chemistry, the biological sciences and the earth sciences showed a significant variation in the definitions within a discipline and between the disciplines. Specifically, the physics and chemistry textbooks used ‘energy in transit’ or ‘transfer of energy’ definitions (Class I), whereas textbooks from other disciplines typically used definitions which relate heat to ‘molecular kinetic energy’ (Class II) or they used a hybrid of Class I and II definitions. Although a universal definition of heat across disciplines may not be possible (or even desirable), we suggest that discrepancies in definitions be acknowledged and clearly communicated to students. 相似文献
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丁斌 《温州职业技术学院学报》2006,6(1):31-33
低温热水地面辐射供暖系统由于其舒适、卫生、保健、不占面积、热稳定性好、高效节能等优点已越来越多地在建筑供暖中得到推广应用。该供暖系统的施工必须严格按照施工工艺操作进行。 相似文献
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Arunn Narasimhan 《Resonance》2008,13(7):638-647
In this essay we shall try to answer the question in the title with some geometry and heat transfer thrown in for effect.
For doing so, as the joke goes, allow me to assume the elephant as a sphere. The reason will be apparent soon.
Arunn Narasimhan is a faculty at the Indian Institute of Technology Madras. His research interests include transport in porous
media, phase change materials and heat transfer in biological systems. 相似文献
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