共查询到20条相似文献，搜索用时 218 毫秒
1.
吴华太 《中学物理教学参考》1996,(12)
气体自由膨胀浅析江苏省高邮市八桥中学吴华太一、问题的提出在讨论气体做功时，经常要根据气体体积的变化情况来确定气体做功的性质，例如气体体积不变时，气体不做功，体积缩小时，外界对气体做功．气体在等温膨胀、等压膨胀及绝热膨胀的过程中都要对外做功，能否由此可... 相似文献
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本文从理想气体绝热自由膨胀过程的本质出发,进一步论述了理想气体的绝热自由膨胀过程和等温膨胀,一般绝热过程的关系。澄清了一些易于忽略的错误认识。 相似文献
3.
李雪梅 《河北工业大学成人教育学院学报》1999,(1)
焦耳─汤姆逊效应又称节流效应,是指流体经过节流膨胀过程前后的焓不变,其在工业上的重要用途是让流体经过节流阀进行节流膨胀,以获得低温和液化气体1焦耳─汤姆逊实验1843年焦耳通过实验得出结论：气体的内能和消只是温度的函数,而与体积和压力无关。此结论只适用于理想气体,对于实际气体就不适用了。1852年焦耳和汤姆逊设计了另外一个新实验,设法克服了由于环境热容量比气体大得多,而不易观察到气体膨胀后温度可能发生变化的困难,比较精确地观察了气体由于膨胀而发生的温度改变。实验装置如图1。在一绝热圆筒的中部,有一刚性多孔… 相似文献
4.
利用量子统计的研究方法 ,结合光子气体的特点 ,对光子气体的热性能进行研究 ,证明了光子气体的分布、普朗克公式及斯特藩_玻耳兹曼定律 .得到了光子气体的内能、热容量、焓、自由能、吉布斯函数及绝热系数的表达式 相似文献
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6.
曾柱石 《广东教育学院学报》2005,25(5):57-59
综述气体温度随体积膨胀而变化的三种实验过程,导出焦耳系数的第二位力系数[B（T）]表示,从理论上证实焦耳实验结果的不可靠;对范德瓦耳斯方程改正项a（T）和b（T）作半定量分析,由此给出焦汤实验存在反转温度的更明显的微观解释. 相似文献
7.
用气体压力传感器、放大器、数字电压表和数字示波器,自制一台数字式气压计,用于分别测量容器中空气的等温膨胀和绝热膨胀时气体压强与体积的关系,验证玻意耳定律和绝热过程的泊松公式,准确求得气体比热容比,实验误差一般小于3%.该实验可以在高等学校基础物理实验中推广. 相似文献
8.
用压缩空气引火仪不仅能演示绝热压缩即外界对筒内气体作功时气体温度升高,还能演示气体绝热膨胀时的降温,即气体对外作功时气体本身内能减少。先往压缩空气引火仪底部注入一、二滴酒精或乙醚,然后将活塞插入筒中,缓缓压下,直到活塞离筒底不到1厘米时停住。然后突然放开手,使引火仪中空气自动膨胀, 相似文献
9.
最近读本刊 2 0 0 2年第 5期 ,对《气体体积增大 ,一定对外做功吗 ?》一文感受颇深 ,笔者在中学物理教学近 1 0年中 ,也形成了这类问题的思维定势 .而且现在的许多资料对此类问题也存在认识上的错误 .这里有必要对该问题作进一步的澄清和完善 ,以供广大教师教学参考 .1 正确区别气体体积“增大”和“变大”( 1 )气体体积“增大”一定质量的理想气体从状态A变化到状态B ,在变化过程中 ,气体体积一直在膨胀 ,我们说气体体积增大 ,如等温膨胀 ,等压膨胀 ,绝热膨胀等 .图 1 图 2 图 3 图 4( 2 )气体体积“变大”一定质量… 相似文献
10.
气体对外做功，内能减少是高中物理新教材第二册第十一章中新增的演示实验。实验要求用灵敏温度计测出气体压强增大到一定程度时，温度计的示数和气体冲开胶塞后温度计的示数明显变小，用于验证空气在膨胀时对外做功，内能减少，温度降低。但是一般中学的物理实验室只配备热敏温度计，而且热敏温度计对变化的温度的反应并不灵敏，要等数秒钟后才能达到热平衡。所以不能把气体绝热压缩时升高的温度及气体绝热膨胀后降低的温度比较真实地显示出来。本人制作的这套教具，找到了一种性能优良的灵敏温度计，能把气体绝热压缩时升高的温度及气体绝… 相似文献
11.
Use of self-generated analogies has been proposed as a method for students to learn about a new subject by reference to what they previously know, in line with a constructivist perspective on learning and a resource perspective on conceptual change. We report on a group exercise on using completion problems in combination with self-generated analogies to make sense of two thermodynamic processes. The participants (N = 8) were preservice physics teacher students at the fourth year of the teacher education program. The students experienced challenges in accounting for the constant entropy in reversible, adiabatic expansion of an ideal gas and the constant temperature in free, adiabatic expansion of an ideal gas. These challenges were found to be grounded in the students’ intuitive understanding of the phenomena. In order to come to terms with the constant entropy in the first process, the students developed idiosyncratic explanations, but these could by properly adjusted given suitable scaffolding. In contrast, the students by themselves managed to make sense of the constant temperature in free expansion, by use of microscopic explanatory models. As a conclusion, self-generated analogies were found to provide a useful approach to identifying challenges to understanding among students, but also for the students to come to terms with these challenges. The results are discussed against a background of different perspectives on the issue of conceptual change in science education. 相似文献
12.
潘玉灼 《泉州师范学院学报》2002,20(6):33-36
应用热力学理论以及费米积分的特性，导出理想费米气体焦汤系数的解析表达式，详细讨论了低温下费米气体的定压热容和焦汤系数，并阐明了费米气体的量子本性对焦汤效应的影响，结果表明理想费米气体的焦汤效应为负效应。 相似文献
13.
毕青华 《十堰职业技术学院学报》2010,23(5):44-47
伴随工业活动而生的温室气体对全球的气候产生了恶劣的影响:自然灾害的频发、极端气候天气的不断涌现。这引起了地球人的恐慌。但大气作为一种特殊的全球公共物品,仅仅依靠某一国或某几国的努力也很难应对全球的气候变化,因而这就需要世界各国尤其是大国的密切合作。《京都议定书》的生效是国际气候制度发展的重要里程碑,它标志着应对气候变化的国际合作迈出了重要的一步,其对世界经济和国际政治关系也产生了重大影响。但无论是从其内容还是效力上看都有其局限性,尤其是世界第一大二氧化碳排放国——美国拒绝批准,在《京都议定书》下的应对气候变化的国际合作并不如人所愿。本文正是从应对气候变化的国际合作的问题着手,分析其原因并为之后国际合作谋出路。 相似文献
14.
李福安 《黄山高等专科学校学报》2014,(3):13-16
利用电弧炉熔炼法分别制备了LaFe11.2Co0.7Si1.1B0.2,LaFe11.1Co0.8Si.iB0.2和LaFe11Co0.9Si1.1B0.2化合物.磁性测量和计算得到该系列化合物的等温磁熵变,利用直接测量法测量该系列化合物在外加磁场为0-1.5T下的绝热温变.最后分别计算基于等温磁熵变和绝热温变的相对制冷能力. 相似文献
15.
The main objective of this study is to establish a relationship between students' understanding of gases and its parallels in the history of science (rational reconstruction). Fifty-nine freshman students were asked to respond to a gas problem that did not require any calculations but rather conceptual understanding (due to molecular collisions, gases occupy all the available space). Before responding to the problem students were exposed to an elementary version of the kinetic theory of gases. Results obtained showed that a large proportion of the students gave explanations that approximate quite closely to an idealized form of the Lattice Theory of Gases. This theory considered molecules in gases to be arranged in the form of regular lattices, rather as if gases were highly expanded solids, and was held by most chemists until about 1860. It is concluded that some of the students' alternative conceptions about gas behavior (attractive forces between gas molecules increase as the temperature decreases) are resistant to change and recapitulate theories scientists held in the past. 相似文献
16.
R. Srinivasan 《Resonance》1996,1(12):6-16
Absolute zero of temperature is unattainable. One may approach as close to absolute zero as technically possible. In this
four part series an attempt will be made to trace developments in the approach to absolute zero. In Part I, I will explain
the principles governing liquefaction of gases. 相似文献
17.
Sudhir R. Jain 《Resonance》2014,19(9):797-813
The idea of adiabatic invariance is presented in the context of simple classical mechanical models. The adiabatic invariant jumps across the separatrix — an attempt has been made to bring out the basic ideas underlying the Melnikov-Arnold integral. This becomes important as soon as a perturbation to a regular, stable system makes it dynamically unstable. 相似文献
18.
大气温度随高度变化率的推导 总被引：1，自引：0，他引：1
柳福提 《河南科技学院学报》2007,35(2):32-32,45
在对流层内,运用理想气体绝热过程的理想模型,从理论上定性分析了大气温度随高度升高而下降的原因,定量推导了其变化率,并把结果与实际测量值进行了比较分析。 相似文献
19.
A homogeneous theoretical model is developed to predict the performance of R22 and R290 in adiabatic capillary tubes. The model is based on conservation equations of mass, momentum and energy. Metastable both liquid and two-phase flow regions are considered in the model. In metastable two-phase region, superheated liquid is introduced into the metastable mixture viscosity and two methods are presented to evaluate it. The model is validated by comparing the predicted pressure and temperature profile and mass flow rate with several investigators′ experimental data of R22 and one of its alternatives R290 reported in literature. All of the predicted mass flow rates are within ±8% of measured values. Comparisons are also made between the present model and other investigators′ models or sizing correlation. The model can be used for design or simulation calculation of adiabatic capillary tubes. 相似文献
20.
本文以伯塞活脱气体为例，定量分析了焦耳——汤姆逊效应致冷（致热）的原因，导出了伯氏气体焦耳——汤姆逊效应的转换温度与压强的关系。 相似文献