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习题课,是物理教学中的一个重要环节,通过习题课可加深学生对概念的理解,提高学生分析问题和解决问题的能力.本文就如何上好物理课作一探讨.1注重习题的层次性:通过一些有层次的习题教学,可帮助学生掌握明晰的解题思路,提高学生的解题能力.例如在库仑定律的教学中,习题课可按如下层次进行.首先让学生做可以直接营公式的简单题.如求两个带电量分为Q1=2.0×10-8C,Q2=1.0×10-7C的点电荷相距0.3m时的相互作用力,学生很容易做了出来,接着可举:如图1所示,真空中A、B两点各固定着一个带电微粒,它们所带的电量分别是Q1=5… 相似文献
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转化与化归思想是高中数学中重要的数学思想方法之一,学生转化与化归能力的高低,决定了解题能力的高低,因此对转化与化归能力的培养显得尤为重要.下面就其转化的基本方向,举例说明. 相似文献
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题已知m,n为正整数,1)用数学归纳法证明,当x>-1时,(1 x)m≥1 mx;2)对于n≥6,已知(1-n1 3)n<21,求证:(1-n m3)n<(21)m,m=1,2,…,n.3)求出满足3n 4n … (n 2)n=(n 3)n的所有正整数n.分析1),3)见标答,略.2)记xn=(1-n1 3)n=(nn 23)n,则xn1-1=(nn 12)n-1=1·(nn 12)·(nn 12)…(nn 12)(n-1)个<[1n(1 nn 12 nn 12 … nn 12(n-1)个)]n=(n2n 22 nn-1)n.∵n2n 22 nn-1相似文献
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Phase-dependent inversionless gain in a four-level atomic system with a closed interaction loop 下载免费PDF全文
A four-level atomic system with a closed interaction loop connected
by two coherent driving fields and a microwave field is
investigated. The results show that inversionless gain can be
achieved on a higher frequency transition outside the closed
interaction loop, and the gain behaviour can be modulated by the
phase of the closed loop as well as the amplitude of the microwave
field. The phase sensitivity property in such a scheme is similar to
that in an analogous configuration with spontaneously generated
coherence, but it is beyond the rigorous condition of
near-degenerate levels with non-orthogonal dipole moments.
Therefore this scheme is much more convenient in experimental
realization. 相似文献
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2007年全国高考数学湖北卷压轴题的探究与评析 总被引:1,自引:0,他引:1
题 已知m,n为正整数,
1)用数学归纳法证明,当x〉-1时,(1+z)^m≥1+mx; 相似文献
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Amplification mechanism and effects of spontaneously generated coherence on the probe gain in a four-level system 下载免费PDF全文
We investigate the amplification mechanism in a four-level system by both the density-matrix and quantum-jump approaches. We show that the asymmetry between three-photon stimulated emission and one-photon absorption process is responsible for the inversionless amplification of the probe field. We also investigate the effects of spontaneously generated coherence (SGC) on the probe gain, and find that due to the SGC, the probe gain can be greatly enhanced and can be modulated by changing the relative phase between the applied fields. 相似文献
7.
Influence of Doppler-broadening on absorption-dispersion properties in a resonant coherent medium 下载免费PDF全文
We investigate the influence of Doppler broadening on absorption-dispersion
properties in a four-level atomic system that can evolve from a normal
dispersion to an anomalous dispersion. Our results show that the absorption-dispersion
properties become strongly dependent on the propagation directions of the
applied fields if Doppler broadening is taken into account. Especially, the
switchover in the sign of the dispersion is still achievable even in the
presence of Doppler broadening if properly arranging the propagation
directions of the applied fields, which is in contrast with the otherwise
behaviours in some other configurations. 相似文献
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