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在电磁学中 ,学生判断通电导线周围磁场方向的安培定则 (亦即右旋定则 )、判断通电导线所受磁场力方向的左手定则以及判断感应电流方向的右手定则 ,经常出现搞不清到底是用左手还是用右手 ,而“左手因果定则”可以很好地避免上述定则的缺憾 ,所谓“左手因果定则” ,就是四指指原因 ,拇指指结果 .学生在使用过程中也认为“左手因果定则”易记、易学、好用 .现将用该定则在判断磁场方向、通电导线的受力方向及感应电流的方向的具体作法介绍如下 :1 用“左手因果定则”判断磁场方向 在这里 ,电流是原因 ,磁场是结果 .1 .1 判断通电导线周… 相似文献
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判断通电导线在磁场中所受磁场力方向的左手定则;判断导体切割磁感线时,导体中产生的感应电流的方向(感应电动势方向)的右手定则是电磁学中两个非常重要的定则.容易出错、混淆.用右手螺旋定则代替左手定则和右手定则,学生反映容易记、容易掌握.教学效果好.现就用... 相似文献
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在高中物理电磁学中,判断通电导线和运动电荷在磁场中受力方向的定则——左手定则有着举足轻重的作用.所有高中物理教材在讲述这一定则时,都是做完磁场方向与电流方向相互垂直的有限几个实验,就陈述定则内容,跳过了归纳总结得出规律的推导过程,使得左手定则的出现非常突然,让人对该定则的普适性存在疑问.笔者认为这种教学思路未很好地体现《高中物理新课程标准》中“让学生体验探究过程,了解科学研究方法”的思想. 相似文献
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本文与郭振华的《洪德定则的理论解释》一文(本刊1987年第5期)都是讨论洪德定则的.郭文着重分析物理图象,比较简明,而本文则对洪德定则的表述及其理论解释都作较严格的讨论.两文各有特色,读者在阅读本文时可参阅郭文. 相似文献
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左手定则和右手定则的正确认识和运用金演宁(浙江省医药学校宁波315010)1弄清左手定则和右手定则适用范围,正确选择解题方法左手定则是判定磁场力方向的,它适用于磁场对场内通电导线(电流)或运动电荷产生作用力的情形;右手定则是判定感应电动势(或感应电流... 相似文献
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电磁学中的左手定则是用来判定磁场对通电直导线的作用力方向的 ,而右手定则是用来判定感应电流方向的 .教学中发现这两个定则在记忆上很容易发生混乱 ,学生使用时常常会伸错手 ,那么能不能用某一种方法来“替代”左手定则和右手定则呢 ?作者认为是可以的 .根据安培公式 F=BIl, 相似文献
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确定同科电子原子谱项的偶数定则 总被引:8,自引:2,他引:6
本文提出同科电子体系在L-S耦合中必须遵守偶数定则,并加以理论论证,利用偶数定则可以很方便地确定二个同科电子所形成的原子谱项. 相似文献
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用实验室中的铅蓄电池和干电池来做电路规律实验操作比较复杂,实验数据规律不明显.为了更好地演示电路规律,自制了可精确控制内阻的电源,教学中使用方便可靠,实际测量数据非常理想,可以很好地让学生探究并发现规律. 相似文献
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Hermann Grabert Gert-Ludwig Ingold Michel H. Devoret Daniel Estève Hugues Pothier Cristian Urbina 《Zeitschrift für Physik B Condensed Matter》1991,84(1):143-155
The rate of electron tunneling through normal metal tunnel junctions is calculated for the case of ultrasmall junction capacitances. The so-called Coulomb blockade of electron tunneling at low temperatures is shown to be strongly affected by the external electrical circuit. Under the common experimental condition of a low impedance environment the Coulomb blockade is suppressed for single tunnel junctions. However, a Coulomb gap structure emerges for junctions embedded in a high impedance environment. For a double junction setup a Coulomb blockade of tunneling arises even for low impedance environments due to the charge quantization on the metallic island between the junctions. An approach using circuit analysis is presented which allows to reduce the calculation of tunneling rates in multijunction circuits to those of a single junction in series with an effective capacitance. The range of validity of the socalled local rule and global rule rates is clarified. It is found that the tunneling rate tends towards the global rule rate as the number of junctions is increased. Some specific results are given for a one-dimensional array of tunnel junctions. 相似文献
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基于累积释放模型提出了一种累积放电模型.相比于累积释放模型, 累积放电模型无须变化的阈值调制, 即可出现多种状态, 例如混沌态、锁频等. 利用符号动力学对其进行研究, 发现在一定的参数条件下, 模型的输出符号序列可以被用于监测模型参数的变化, 而且与神经系统的测量相似, 都具有很高的分辨率. 计算机仿真和电路实验得到的结果也验证了上述说法. 电路实验结果显示模型的输出符号序列对输入频率的分辨率最高可以达到0.05 Hz, 对电流幅值的分辨率可达到1 μA, 并且都具有很大的动态范围.
关键词:
符号动力学
混沌
累积释放模型
非线性电路 相似文献
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Thermal effect and energy-level transition rule for themesoscopic LC circuit with inductance--capacitance coupling
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<正>This paper reports that the mesoscopic inductance and capacitance coupling LC circuit is quantized by means of the canonical quantization method.Using the ’invariant eigen-operator’ method,it deduces the energy-level transition rule when the system is disturbed by an external electromagnetic field.At the same time,the quantum fluctuations for the system at finite temperature are examined by virtue of the generalized Hellmann—Feynman theorem. 相似文献
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Gert-Ludwig Ingold Petra Wyrowski Hermann Grabert 《Zeitschrift für Physik B Condensed Matter》1991,85(3):443-449
The influence of envirommental impedances on tunneling rates in a single electron transistor circuit is investigated. Effects of the finite gate capacitance and of stray capacitances at the tunnel junctions are considered. For the case of a low impedance environment the electron tunneling rates reduce to the so-called global rule rate while for a high impedance environment a modification of the so-called local rule rate arises from the stray capacitances. Special emphasis is given to the dependence of the current on the gate voltage which determines the sensitivity of electrometers based on the transistor setup. It is found that a higher sensitivity of the electrometer can be achieved by means of asymmetric transistors. 相似文献
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给出了求解动态电路冲激响应初始值和动态奇异电路响应初始值的一种简易方法.在电路换路后,其电容电压或电感电流的初始状态一般不产生跃变,但有时也可能产生跃变,当一时难于确定时,可先将电路化为其s域模型,并将0-值带进换路后的电路模型,再应用拉氏变换的初值定理,即可在s域解决t域响应的初始状态0 值的问题.该方法广泛适用于各种电路. 相似文献
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Soonwoo Kwon Jongheop Yi Sewang Yoon Joon Sung Lee Donghwan Kim 《Current Applied Physics》2009,9(6):1310-1314
The effect of different surface morphologies obtained by anisotropic etching on the light trapping and short circuit current of single crystalline silicon solar cells was investigated. The anisotropic texturing of a (1 0 0) silicon surface was performed using potassium hydroxide (KOH) solution and/or tetramethylammonium hydroxide (TMAH) solution including isopropyl alcohol (IPA) additive or tertiary butyl alcohol (TBA) additive. Texturing in TMAH solution formed smaller pyramids on the textured surface compared with texturing in KOH solution. Although the textured samples showed similar reflectances (except in the case of the TBA additive), they showed different short circuit currents. Texturing in KOH/TMAH solution led to a 9.6% increase in short circuit current compared with texturing in KOH/IPA solution, a typical etchant in commercial processes. Based on these results, the reflectivity has no simple proportionality relationship to the short circuit current, and the short circuit current of silicon solar cells should be the criterion used in evaluating texturing effects on reducing reflectance and forming a sound junction with high collection efficiency. 相似文献