共查询到20条相似文献,搜索用时 78 毫秒
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传统的物理教学是以线性问题为基础,根本不涉及或者回避非线性问题,即使碰到非线性问题,我们也常常把它简化为线性问题来处理,由此学生往往认为事物的运动具有确定性,而现实生活中事物发展的不确定性是普遍现象.现行高中物理教材(全日制普通高级中学教科书(必修加选修)物理第二册,普通高中课程标准实验教科书物理选修3-1)在“恒定电流”一章提出了“非线性元件”,并且在学生实验中增加了“测绘小灯泡的伏安特性曲线”的探究性实验,让学生初步接触了非线性现象.在近几年高考中,“非线性”类试题已成为考试的热点,因它在考查学生的基本实验素养和创新能力方面有独特的功效.然而,由解决线性问题形成的传统观念却柬缚了学生的思维,以至遇到非线性问题总用僵化的方法去思考,导致结果不正确.笔者想通过对有关“非线性”高考题的分析和讨论,来揭示这类考题的命题特点,形成应对这类考题的教学策略,达到提高高三物理复习教学效益的目的. 相似文献
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我校(初中)在这两年开展了“学生自主实验”.这是因为新的物理课程,要求教师尽快地从“为考试而教”转变为“为创造而教”,不再是“教参~教材一学生”的教学程序和模式,而要变成“学生一活动一教材”的物理教学新模式,从而进入到教育创新的广阔天地.基于这种教学理念,我校“学生自主实验”区别于课堂上的教师演示实验与学生实验,是学生在已有知识基础上自主质疑,应用学校实验室提供的仪器及化学药品(仪器及药品目录挂在实验室外墙上,学生可以随时查阅),自拟探究课题,或选择实验室提供的课题(课题也在实验室外墙上), 相似文献
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近几年来物理实验内容在高考中的权重基本保持在13%~15%,实验内容涉及演示实验和设计实验等,试题的形式多样,面貌不断创新,越来越引人瞩目。从增强学生的实验意识,培养实验思维,提高实验能力出发,物理实验的复习策略必须注重“细致性”和“创新性”两个方面的整合。 相似文献
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在高中物理教学中,“水波的干涉”、“布朗运动”和“静电实验”是三个较难做好的演示实验.“水波的干涉”实验的主要问题是看不到明显而规则的强弱条纹;“布朗运动”实验的主要问题是要么显微镜中看到的是黑洞洞的一片,要么镜头被沾湿弄脏;“静电实验”的主要问题是漏电,一漏电什么也做不成.这三个实验其实都有诀窍,如果我们能像刑警“破案”一样仔细分析每个实验做不成的原因,问题就可以解决. 相似文献
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Shvartsburg AA Hudgins RR Dugourd P Gutierrez R Frauenheim T Jarrold MF 《Physical review letters》2000,84(11):2421-2424
The hypothesis that fullerenes grow in a carbon plasma by the addition of C2 units (the "fullerene road") has been widely acclaimed as the most plausible mechanism for formation of larger fullerenes including C60 and C70. Calculations suggest that the association of C2 with fullerenes proceeds through two classes of intermediates, "sticks" and "handles." Here we report the observation of these species using high-resolution ion-mobility measurements for C(n) cations generated by laser vaporization of graphite and laser desorption of C60. Sticks with up to eight-atom chains have also been found. 相似文献
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We demonstrate the existence of a class of optical beams where the nonconservative forces can be locally oriented in a direction opposite to the propagation wave vector. Objects placed in the vicinity of these locations will move toward the source of light. The behavior of these negative forces is discussed for the particular case of nondiffracting rotating scale-invariant vector electromagnetic waves. 相似文献
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WANG Hai CHANG Hong WU Haibin XIE Chande 《量子光学学报》2004,10(Z1):22-22
We present a new experimental demonstration that the threshold points and shape of OB hysteresis curve in a four-level Rb atomic system inside an optical cavity were controllably changed by optical signals.Tuning the triggering optical signal to two different transitions of the atomic system we found that the OB threshold points shift toward different direction and at the same time the shape of the OB curve is also changed.For a given intensity of probe laser the OB system can be reliably inversed from its lower stable state to upper state under the triggering of a suitably tuned optical pulse signal (we named it up-controlling signal).More interesting, the inversed OB state does not drop to its initial lower stable state after the triggering pulse signal has passed, but moves to the upper branch of the initial OB curve and stably stays there until another optical signal tuned on other atomic transition (named down-controlling signal) coming.The result shows that there is the ability of information storage in the OB system.The experiments are reasonably explained with the change of cavity resonant condition resulting from the enhanced third-order nonlinearity in multilevel atomic system owing to atomic coherence. 相似文献
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从前,有一个小伙子在外地当学徒,当他获悉在家乡的年老父亲病危的消息后,便立即启程赶路.由于思念心切,他选择了全是砂砾地带的直线路径.当他气喘吁吁地赶到父亲眼前时,老人刚刚咽了气.小伙子不觉失声痛哭,邻舍劝慰小伙子说,老人在弥留之际还不断喃喃地叨念“胡不归?胡不归?”.对这个古老的传说,引起了人们很多的思索,小伙子要能稍早些到家,就不会出现这种遗憾了. 相似文献
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Articulatory interpretation of the "singing formant" 总被引:2,自引:0,他引:2
J Sundberg 《The Journal of the Acoustical Society of America》1974,55(4):838-844
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中学物理教学中"光谱及光谱分析",虽然篇幅不多,但内容丰富.由于这部分内容有些方面所需的知识,超过中学的要求,所以学生在学习中常会提出许多问题.这里选择若干典型问题,作一定性解释,以帮助学生进一步理解这些内容. 相似文献