共查询到19条相似文献,搜索用时 484 毫秒
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本文对受激核的热力学描述做了基本的分析. 根据测不准关系与涨落概念,采用核的核子气模型, 给出了在定量使用温度和熵概念时,该小系统粒子数 的限制条件. 相似文献
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热成像系统的空间和温度分辨极限 总被引:1,自引:0,他引:1
从辐射传递理论出发,运用空间分辨和温度分辨的概念,分析了热成像系统的对给目标背景的极限分辨距离和望远镜头的选用准则,最后对给定系统进行了计算。 相似文献
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普遍色散关系下的热波长 总被引:1,自引:0,他引:1
指出目前教科书和文献所用的热波长概念仅适用于非相对论性系统,而本文引进了普遍热波长的概念。由此可使理想量子气体的热力学函数表示成统一的简洁形式,并进一步揭示了热波长的物理内涵。另外还导出玻色-爱因斯坦凝聚温度和费米温度间的普遍关系。 相似文献
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布拉格光纤光栅热稳定性研究 总被引:2,自引:0,他引:2
分析了布拉格光纤光栅纤芯折射率和光栅反射率随温度和时间变化的规律,应用有关模型提出了加速衰变的概念,并由此建立了相关退火工艺。利用衰变曲线可预测光栅在给定时间和温度下的特性,理论和实验结果相吻合。 相似文献
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热与温度概念评估(Heat and Temperature Conceptual Evaluation,HTCE)是一份基于教学研究的用于测量学生对热与温度相关概念理解的量表.该量表包含对热与温度概念、冷却速率、量热法、传热速率、感知热的能力、比热容、相变和导热性等8个方面的概念考查,从问世至今已在国外物理教育研究中广泛应用,但在国内少有应用与研究.文章就HTCE量表进行详细介绍,概述其近年来的研究进展,并将笔者在疫情期间《热学》课程上的初测结果与国外的结果进行了简单比较.希望能为广大物理教师及物理教育类研究生介绍一份测量工具,为教学研究提供参考. 相似文献
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引入局域热平衡概念,用Damour-Ruffini方法和薄膜模型研究了缓变动态Kerr-Newman黑洞的Hawking辐射和熵.得到了黑洞的Hawking温度和辐射谱公式,Hawking温度随时间和视界面上的位置而变化,辐射谱为准黑体谱;计算了黑洞熵,当取与静态球对称黑洞情况相同的截断关系时便得到了黑洞的Bekenstein-Hawking熵.结果表明,缓变动态黑洞的温度是局域量,缓变动态黑洞的熵与稳态黑洞情况一样正比于黑洞视界面面积.
关键词:
缓变动态黑洞
Hawking辐射
黑洞熵 相似文献
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Edward Bormashenko 《Entropy (Basel, Switzerland)》2020,22(12)
The meaning and evolution of the notion of “temperature” (which is a key concept for the condensed and gaseous matter theories) are addressed from different points of view. The concept of temperature has turned out to be much more fundamental than conventionally thought. In particular, the temperature may be introduced for systems built of a “small” number of particles and particles at rest. The Kelvin temperature scale may be introduced into quantum and relativistic physics due to the fact that the efficiency of the quantum and relativistic Carnot cycles coincides with that of the classical one. The relation of temperature with the metrics of the configurational space describing the behavior of systems built from non-interacting particles is demonstrated. The role of temperature in constituting inertia and gravity forces treated as entropy forces is addressed. The Landauer principle asserts that the temperature of a system is the only physical value defining the energy cost of the isothermal erasure of a single bit of information. The fundamental role of the temperature of the cosmic microwave background in modern cosmology is discussed. The range of problems and controversies related to the negative absolute temperature is treated. 相似文献
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三波长测温中波长选取原则的理论分析 总被引:1,自引:0,他引:1
建立了在窄波段内具有普适性的无量纲化线性发射率模型,对基于此模型而提出三波长温度测量法,着重说明了三波长法适用的测量条件以及3个测量波长的选取原则。在波长选取原则的理论分析中,通过优化分析,依据由测量坐标而引出的等温线的概念,提出了两种理想测量的波长优化准则,从而为该方法的技术实现提供了重要的理论指导,同时该准则的优化思想也适用于多波长法的波长选取。 相似文献
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由于新研制的3 GPa熔融盐固体介质高温高压三轴实验系统改进了高压容器的装样方式以及样品的尺寸,需要对新装置的压力容器进行温度标定,为此采用多个NiCr-NiSi热电偶,在围压为0.5 GPa时对样品内部和周围的温度分布进行了研究。实验结果表明,样品外侧相对于样品中心上1/3位置热电偶监测到的温度与其它位置监测到的温度之间具有良好的线性关系,它们之间的斜率大小可以直接反映出温度的高低。样品外侧相对于样品中心上1/3位置与下1/3位置监测温度基本相同,也可以作为实验控制温度;样品中心温度比样品外侧相对于样品中心上1/3位置和下1/3位置监测温度低4%;样品底部温度比样品中心温度低5%;样品内部相对于样品中心下1/4位置温度比样品中心低2%。样品的温度从中间向两端对称式递减,在样品尺寸范围内,样品的垂直温度梯度恒定(900 ℃为16 ℃/mm)。本设备样品温度分布和温度控制精度与国际同类型实验设备相类似,达到了国际同类设备的水平。 相似文献
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R22与其替代工质的性能比较与分析 总被引:7,自引:0,他引:7
1前言传统的单工质蒸气压缩理论循环分析认为在冷凝器和蒸发器中,制冷剂的冷凝温度和蒸发温度等于相变温度,而忽略了压缩机进出口的过热段以及冷凝器出口过冷段的温度变化,直接造成了人们对回热循环和过热循环的认识偏差,产生了许多误解,其评价标准是有缺陷的。本文以变温热源的可逆循环为基础,考虑了在实际中是可以利用的过热段以及过冷段的温度变化,假设在冷凝器和蒸发器中,制冷剂与外界高、低温热源无换热温差,使循环更接近可逆循环。以此为基础的当量温度法可完善单工质的理论循环分析,同时可用于朗肯循环与劳伦兹循环之间的… 相似文献
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Won Chan Park Arvind Atreya Howard R. Baum 《Proceedings of the Combustion Institute》2009,32(2):2471-2479
An energy and mass balanced method of determining the pyrolysis temperature is proposed. The concept is to find the pyrolysis temperature that consumes the same amount of energy to produce the same amount of mass when using the pyrolysis front model as when using finite rate kinetics models for the entire charring process. The resulting pyrolysis temperature has the form of pyrolysis rate weighted average temperature. Comparisons between finite rate kinetics and pyrolysis front models for various boundary conditions, geometries, heats of decomposition, kinetic parameters and assumptions used in the literature were made to assess the proposed method. Models using energy and mass balanced pyrolysis temperature show good agreement with finite rate models and the experiments. Extensive numerical studies on various factors influencing the charring material pyrolysis show that heat flux, sample size, heat of decomposition and kinetic parameters are the most important factors for determining an appropriate pyrolysis temperature. Thermal conductivity, specific heat and density have a lesser effect on the pyrolysis temperature. For practical application, a non-dimensional correlation is developed to determine the appropriate pyrolysis temperature without solving the problem by using finite rate models. With this correlation the energy and mass balanced pyrolysis temperature can be determined with a standard deviation of 7.6 K. These predictions are validated by comparison with measurements of wood cylinder pyrolysis. A good agreement suggests that simpler pyrolysis front models yield practically useful and accurate results given an appropriate pyrolysis temperature. 相似文献