共查询到19条相似文献，搜索用时 125 毫秒
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本文运用不同的方法讨论了电场中带电谐振子在坐标表象中的能量本征值和本征函数的求解方法,认为电场中带电谐搌子不仅可以用定态微扰的方法求近似解,而且其精确解也可以找到． 相似文献
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伏振兴 《宁夏师范学院学报》2007,28(6):1-5
利用缀饰态表象讨论了二能级原子系统的跃迁过程;从量子干涉的角度对原子跃迁过程给出了非常清晰的理论描述.在其表述中揭示出脉冲面积在量子干涉效应中扮演着十分重要的相位因子功能,表明了激发光场的演变对原子跃迁的控制作用. 相似文献
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从塞曼效应的实验现象入手,分别利用半经典半量子理论和量子力学微扰跃迁对正常塞曼效应进行了解释. 相似文献
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该文分析了一个四能级原子系统受到两束相干光的共同作用时,在缀饰态表象中计算能量和能级状态波函数,同时分析缀饰态能级与基态之间跃迁发生的相干效应,应用此结果可以较好地解释辐射场中原子系统的各相干效应. 相似文献
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本介绍量子力学中一种新的定态微扰展开法，可以方便地得到能级的高级修正，计算时只需知识未受微扰的本征函数和本征值，而无需涉及到其他可能的本征态和本征值。 相似文献
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运用线性稳定性分析法严格证明，某些微扰ＫｄＶ方程的孤子解具有条件稳定性。稳定条件被得到为系统参数与初始常数间的一个关系。在该系统下，微扰作用的孤子解处于临界稳定态，湍流产生于临界态附近的混沌区。 相似文献
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赵丽丽 《赤峰学院学报(自然科学版)》2010,26(9):8-9
本文采用含时微扰理论研究含时非均匀弱磁场对一微无限深势阱中电子性质的影响．理论推导表明,在合时非均匀弱磁场的作用下,电子的跃迁概率与作用时间成正比,且只有初态、末态之间满足一定的选择定则时,跃迁才能产生． 相似文献
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本文从密度矩阵的微扰展式出发,在能量表象中,求出非线性谐振子H=((1/2m)P~2 (1/2)mω~2x~2) αx~2的配分函数Z。进而,由热力学公式可得出其它热力学量。 相似文献
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阐述在三能级原子系统中产生的电磁诱导透明现象,在强耦合场作用下,耦合跃迁产生一对修饰态跃迁,把探测场跃迁一分为二,分裂后的两个探测跃迁由修饰态相干对吸收引起相消干涉,从而抑制吸收,使介质在强相干场作用下呈现完全透明现象. 相似文献
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清末股份制企业的政企关系逐渐由政企合一模式向政企分离模式转变，但政府并未彻底放弃以行政权力干预企业经济活动的做法，传统的政府干预经济政策具有很大惯性，使清政府总是试图依靠政治权力直接约束资本主义企业，封建专制政治体制阻碍了政企关系的良性互动。 相似文献
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教学研究的转型及其课题 总被引：10，自引：0，他引：10
Zhong Qiquan Director professor tutor of doctoral candidates at the Curriculum Teaching Research Institute East China Normal University 《教育研究》2008,(1)
我国的教学研究面临着范式转型的挑战。我国教学研究尽管在不同历史时期各自积累了具有一定进步意义的成果,但一味追求"定型化"是我国教学研究的习俗。20世纪90年代末,出现了"学习共同体"与"反思性实践家"这两个概念,作为冲击"定型化"研究的矢量,开辟了教学研究新的平台。新课程背景下的教学研究,归根结底是一种新的"教师文化"的创造。当前,以"校本研修"为中心的教学研究,为中小学教师的教学研究注入了无穷的活力,也为实现教学研究的转型提供了诸多的启示和不竭的思想动力。但是,它离理想的境界还有一段距离,真正实现教学研究的转型尚需排除种种干扰。 相似文献
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During the transition from elementary school to secondary school, in Germany, students are assigned to different school tracks, academic or non-academic, that differ markedly in compositional and institutional characteristics, e.g., the level of cognitive activation and performance standards are higher in academic tracks than in non-academic tracks. Currently, there is a lack of research examining the changes in achievement goals (mastery-approach, performance-approach, and performance-avoidance goals) and in the association between achievement goals and school achievement during the transition to these different school tracks. There were 1646 students who participated in a large-scale, three-wave longitudinal study from Grade 4 to Grade 6. While results revealed only slight differences between the two school tracks, the three types of achievement goals declined over time. In elementary school mastery-approach goals were positively and performance-approach goals negatively associated with school grades. After the transition to secondary school mastery-approach goals predicted school grades positively, whereas performance-approach goals negatively influenced achievement (academic track). Overall, the results indicate that between-school-tracking plays a minor role for the development of achievement goals and the relation between goals and achievement. 相似文献
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《天津大学学报(英文版)》2020,(4)
FePS_3, a classical 2D layered material with transition metal phosphorous trichalcogenides, was investigated as an anode material for Mg ion batteries. We used density functional theory to calculate the Mg storage properties of FePS_3, such as Mg adsorption energy, theoretical specifi c capacity, average voltage, diff usion energy barriers, volume change, and electronic conductivity. The theoretical specifi c capacity of the FePS_3 monolayer is 585.6 mA h/g with a relatively low average voltage of 0.483 V(vs. Mg/Mg~(2+)), which is favorable to a high energy density. The slight change in volume and good electronic conductivity of bulk FePS 3 are benefi cial to electrode stability during cycling. 相似文献
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针对移动式增氧机在风向、水流等干扰下,存在直线路径跟踪偏离与距离控制精度下降的问题,提出采用自抗扰控制策略优化移动式增氧机的航向控制系统。首先通过二阶跟踪微分器优化移动式增氧机航向过渡过程,跟踪输入信号及其微分信号;再通过扩张状态观测器确定移动式增氧机航向系统内部状态信息,计算误差,得到误差反馈量;最后根据扰动估计值得出最终控制量,计算距离、航向角误差,从而将复杂的路径跟踪简化为1个二阶系统,极大减轻控制器复杂度。试验结果表明,采用自抗扰技术的移动式增氧机可将路径跟踪控制距离误差控制在0.2m,航向角误差控制在0.1°,使移动式增氧机克服干扰的影响。 相似文献
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维吾尔、哈萨克族学生汉语连接成分偏误分析 总被引：1，自引：0，他引：1
根据篇章语言学理论并通过对大量语料进行分析后发现,在汉语叙述体篇章中,新疆少数民族学生（主要是维吾尔、哈萨克族学生）对连接成分的使用容易出现以下几种偏误：连接成分的误用、冗余和缺失等。以上偏误主要是由于学生母话的干扰、目的语的负迁移、缺乏汉语语感、教材和教师教学指导不足等原因造成的。 相似文献
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Emerging adulthood presents individuals with increased levels of relational uncertainty, perceived interference, and feelings of conflict or turbulence, especially within the parent-child dyad as children enter emerging adulthood. This study argues the relationship turbulence theory provides a framework to examine parent-child dyads experiencing the transition into adulthood. One hundred and forty-three emerging adults reported on their relationship with a parent, as well as recent interactions with their parent. Structural equation modeling demonstrated the relational turbulence theory is generalizable to parent-child contexts. Further explanation of these results and possible implications of the study are discussed. 相似文献
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This paper assesses the performance of the “National Textbook Development and Distribution Policy for Pre-Tertiary Education” of 2002. It examines the policy in theory and in practice by exploring the extent to which the liberalisation of the textbook trade has helped to improve on textbook procurement, production and distribution, availability, quality and access to the books. The paper discusses the context leading to the transition from the state-controlled policies to the present liberalised textbook provision policies in Africa. The tensions that marked the transition period and the role of the World Bank and other development agencies in the policy shift have also been discussed. The paper identifies a number of implementation challenges stalling the full realisation of the objectives of the textbook policy including the Ministry of Education’s interference in the textbook procurement process and some publishers’ and authors’ abuse of the conflict of interest regulation in the policy. The paper makes a number of recommendations for consideration. 相似文献