共查询到20条相似文献，搜索用时 31 毫秒
1.
Most of the molecules react to form products by climbing a barrier. The energy involved in this climbing of the barrier is known as the activation energy of the reaction. Questions like how fast a reaction occurs can be answered by considering the height of the barrier. However, in some reactions, the reactants transform to products by directly tunnelling across the barrier instead of climbing over it. Such a purely quantum mechanical effect, which becomes more prominent for reactions at low temperatures can lead to interesting and even completely unexpected products. This effect and its consequences in representative examples are discussed. 相似文献
2.
Mario Bunge 《Science & Education》2012,21(10):1601-1610
It is argued that the correct answer to the three questions in the title is ??no??: that the theses being denied derive from traditional philosophy, not from the way the quantum theories are used. For example, the calculation of the energy spectrum of an atom assumes the autonomous existence of the atom, rather than its dependence upon the observer. However, it is also suggested that the problem has been unnecessarily complicated by a careless use of the terms ??realism??, ??materialism??, and ??determinism??. Precise definitions of these words are proposed. 相似文献
3.
利用弯曲时空中标量粒子运动的Hamilton-Jacobin方程,研究一般球对称蒸发黑洞周围时空中标量粒子的能量.得到了粒子的能量不仅与粒子的质量有关,还与黑洞的时空结构及视界的变化有关.给出了粒子在弯曲时空中的能量分布. 相似文献
4.
针对实、虚部关联的量子噪声及泵噪声驱动的饱和激光模型,基于近似福克—普郎克方程,推导激光强度定态概率分布函数,利用投影算子法,分析了由于量子噪声实虚部关联度λq导致锁相时的光强度关联函数C(τ)和集中驰豫时间Tc。通过计算机数据计算及作图,得到了定态情况下光强概率分布函数图形,讨论了量子噪声实、虚部的互关联对光强关联函数和集中驰豫时间的影响。结果表明:量子噪声实、虚部互关联会导致激光强度涨落增大。 相似文献
5.
黑洞是广义相对论所预言的一种特殊的天体．它的基本特征被认为是有一个封闭的视界，即黑洞的边界．外来的物质和辐射可以进入视界以内，而视界的任何物质都跑不到视界以外，甚至连光也逃逸不出来．在介绍黑洞成因的基础上，从黑洞热力学及黑洞量子力学两个不同的方面阐述了黑洞辐射的物理机制，并指出黑洞研究将是本世纪最具挑战性的天文学说之一． 相似文献
6.
吴新忠 《武汉工程职业技术学院学报》2001,13(4):30-34
本文将量子复合时空理论，量子力学交易解释和量子力学曲率解释结合起来，而且将它们推广到广义相对论的弯曲时空框架中，不仅解决了量子场论中的一些重正化问题，而且以黑洞和白洞的时空度规作了新的理解，初步解决了霍全和彭罗斯的量子黑洞问题上的争论，对天体演化和宇宙演化提出了新的观点，有助于量子引力论的进一步发展。 相似文献
7.
利用有效质量近似和变分原理,考虑量子点的3维约束效应,研究了圆柱形闪锌矿GaN/AlxGa1-xN量子点的光学特性随势垒层Al含量的变化关系问题。结果表明,势垒层Al含量对量子点的发光波长、振子强度和激子结合能有重要的影响,激子效应对量子点发光波长的影响很大。 相似文献
8.
张冠芬 《商丘师范学院学报》2006,22(5):71-73
用旋量零标架方法对Vaidya-de Sitter黑洞时空中旋量粒子的Dirac方程分离变量,并退耦为普通微分方程组,从所获得的径向方程和角向方程出发,进一步导出了Dirac粒子的能级方程.得到了粒子的能量分布不仅与粒子的质量、自旋量子数、角量子数、磁量子数有关,还与黑洞周围的时空结构及视界的变化有关. 相似文献
9.
LIU Xiao-ying XIA Shi-fa LI Fang-yu 《重庆大学学报(英文版)》2005,4(4):243-246
1 Introduction a In theoretical physics, the problem of calculating the quantum entropy on black hole background is a hotspot. Much efforts have been devoted to study the quantum entropy via brick-wall model [1] in the last 20 years, and most conclusions [2-6] are the quantum entropy according with Bekenstein-Hawking equation, i.e. S = Ah / 4 where S is the quantum entropy; and Ah is the area of the black hole horizon. But recent research [7,8] shows that the quantum entropy also has the log… 相似文献
10.
P.A.M.Dirac在他的名著《量子力学原理》中关于"电子同时通过两个狭缝"的观点,一直受到人们的批评.对它的理解必然涉及到"电子是否会‘分裂’?"的问题,从而引发了许多歧义和悖论.通常量子力学教科书和研究专著对这个问题一般不做深入分析,造成了很多人对量子力学理论基础的怀疑.这个问题的正确理解与量子力学的"态叠加原理"有关.量子现象表现出许多与宏观现象不同的、新的特点,只有承认它们,并且把它"翻译"成我们所能理解的经典语言去表述它们,我们才有可能得到对微观现象的完整描述. 相似文献
11.
该文避开求解黑洞背景下波动方程的困难,应用量子统计方法,直接求解黑洞背景下Bose场和Fermi场的配分函数.然后利用膜模型,计算黑洞背景下热辐射谱的熵,由此熵寻求被黑洞视界反射回热谱的熵.从而对黑洞熵给出了一种新的解释,即黑洞熵是由辐射谱被视界面反射回的那一部提供的,与视界外的辐射场无关.当取适当的贯穿系数时,得到黑洞熵与视界面积成正比的结论.在所得结论中不存在对数发散项与舍去项,也不存在黑洞视界外标量场或Dirac场为什么是黑洞熵疑难.并且给出粒子的自旋简并度对黑洞熵的影响.为研究各种复杂黑洞熵提供了一条简捷的新途径. 相似文献
12.
牛振凤 《河北北方学院学报(社会科学版)》2003,19(6):8-11
避开求解各种粒子波动方程的困难,直接利用量子统计的方法,计算schwarzschild黑洞背景下Bose场和Fermi场的配分函数,进而采用brick-wall薄膜模型,得到黑洞熵与其视界面积成正比的结论。 相似文献
13.
赵仁 《雁北师范学院学报》2006,22(5):21-24
最近,人们致力于解决黑洞(Bekenstein-Hawking)熵的量子修正问题.尤其是,许多学者对黑洞熵修正项中的对数项系数产生了极大的兴趣.本文,利用广义测不准关系对黑洞熵的修正值进行了计算,给出了由广义测不准关系而引起的修正项.我们在计算中认为Bekenstein-Hawking面积定理在考虑广义测不准关系后仍然成立,我们得到黑洞熵修正项中的对数项系数是正的,与目前人们给出的结论不同.然而我们的方法具有普适性,不仅对单视界时空成立,而且对双视界时空也有效.在整个计算过程中,计算方法简明,物理意义明确.这样我们的结论为进一步研究Bekenstein-Hawking面积定理成立的条件提出了新的课题. 相似文献
14.
《Educational Philosophy and Theory》2013,45(1):35-50
This paper considers questions of continuity and change in education from the perspective of complexity theory, introducing the field to educationists who might not be familiar with it. Given a significant degree of complexity in a particular environment (or ‘dynamical system’), new properties and behaviours, which are not necessarily contained in the essence of the constituent elements or able to be predicted from a knowledge of initial conditions, will emerge. These concepts of emergent phenomena from a critical mass, associated with notions of lock‐in, path dependence, and inertial momentum, suggest that it is in the dynamic interactions and adaptive orientation of a system that new phenomena, new properties and behaviours, emerge. The focus thus shifts from a concern with decontextualised and universalised essence to contextualised and contingent complex wholes. This is where complexity theory seeks the levers of history. The paper posits the notion of inertial momentum as the conceptual link between the principle of emergent phenomena as developed principally in the natural sciences and the notion of socio‐historical change in human society. It is argued that educational and institutional change is less a consequence of effecting change in one particular factor or variable, and more a case of generating momentum in a new direction by attention to as many factors as possible. Complexity theory suggests, in other words, that what it might take to change a school's inertial momentum from an ethos of failure is massive and sustained intervention at every possible level until the phenomenon of learning excellence emerges from this new set of interactions among these new factors, and sustains itself autocatalytically. The paper concludes with a summary consideration of the conditions that contribute to the emergence of new properties and behaviours in a system. 相似文献
15.
Cihan Saclioglu 《Resonance》2010,15(2):104-115
When the small angle approximation is not made, the exact solution of the simple pendulum is a Jacobian elliptic function
with one real and one imaginary period. Far from being a physically meaningless mathematical curiosity, the second period
represents the imaginary time the pendulum takes to swing upwards and tunnel through the potential barrier in the semi-classical
WKB approximation1 in quantum mechanics. The tunneling here provides a simple illustration of similar phenomena in Yang-Mills theories describing
weak and strong interactions. 相似文献
16.
在考虑了广义不确定关系原理的基础上,计算了黎曼时空背景中的一般静态黑洞视界附近的量子态密度。计算结果表明,时空中不存在发散的量子态密度。 相似文献
17.
With rising student demand, time-limited therapy is becoming the rule rather than the exception at college counseling centers today. While many have viewed this shift as an unwelcome intrusion, this article will examine how to embrace and capitalize on this new, compressed form. Rather than seeing it as a constraint, it will be argued that it provides an opportunity to be more poetic and musical about our work, allowing us to take more therapeutic risks, establish greater momentum, and increase the number and variety of transformative moments in our sessions. Emphasis will be placed on the lessons that poetry and music can teach with respects to deepening and enhancing relational psychotherapy with our students. 相似文献
18.
Ning Fang 《Journal of Science Education and Technology》2012,21(5):571-580
A concept pair is a pair of concepts that are fundamentally different but closely related. To develop a solid conceptual understanding in dynamics (a foundational engineering science course) and physics, students must understand the fundamental difference and relationship between two concepts that are included in each concept pair. However, all existing research in dynamics and physics education has been focused on the identification and repair of students?? misunderstanding of individual concepts, but not concept pairs. The present research fills the gap of existing research by studying students?? perceptions of dynamics concept pairs and correlation with their problem-solving performance in both particle and rigid-body dynamics. A total of 88 engineering undergraduate students participated in the present study. Students?? perceptions were assessed using a 40-item instrument that included 20 dynamics concept pairs at fundamental Level One and higher-order Level Two. Students?? problem-solving performance was assessed using four exams that included 66 dynamics problems. The coefficients of reliability (Cronbach??s ??) of assessment instruments vary between 0.69 and 0.93. The research findings from the present study show that students were not confident in their understanding of Level-Two concept pairs, especially the relationship between the Principle of Linear Impulse and Momentum and the Principle of Angular Impulse and Momentum, and the relationship between the Principle of Angular Impulse and Momentum and the Conservation of Angular Momentum. A statistically significant correlation exists between students?? perceptions of Level-Two concept pairs and their problem-solving performance on both particle dynamics (r?=?0.355, p?<?0.01) and rigid-body dynamics (r?=?0.351, p?<?0.01). The research findings made from the present study imply that educational efforts should be focused on improving students?? understanding of Level-Two dynamics concept pairs. 相似文献
19.
周并举 《湘潭师范学院学报(社会科学版)》1998,(6)
为了从另一途径考察黑洞的热力学特性和量子行为,本文将相干态理论引入到弯曲时空,具体讨论了在二维Schwarzschild时空的相干态表示。利用这一相干态表示计算并分析了黑洞的辐射效应（Hawkingeffect）,得出的结果与标准结果一致,这再次反映了霍金辐射（Hawkingradiation）的普适性。 相似文献
20.
富中华 《忻州师范学院学报》2005,21(2):27-28
带电粒子在匀强磁场中作恒定的匀速圆周运动，是一种近似的结论，按照经典的电磁理论作加速运动的带电粒子将不断地向外辐射电磁波，它的能量将不断地减小，其运动的轨道半径也随之减小。另外，在一定的条件下，由于量子效应，带电粒子的运动形式将更加复杂。本文拟对带电粒子在匀强磁场中不同情况下的运动特点及其相应的条件进行分析讨论。 相似文献