共查询到20条相似文献,搜索用时 109 毫秒
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我们设计制作了一种振动综合演示仪 ,不仅可以用它演示简谐振动、拍现象 ,还可以用来演示李萨如图形 ,并介绍了此仪器的结构和原理。 相似文献
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装置为光的合成与色散演示仪。通过调制单片机输出脉冲的占空比可以控制三色LED灯红光、绿光及蓝光的输出亮度,从而合成不同的颜色,相当于模拟电脑系统中的24位真彩色颜色输出。利用凸透镜将光聚焦在白屏上以观察到不同颜色光的合成;用透射光栅代替凸透镜,可以演示光的色散现象。装置可以演示纯色输出、两色等比例输出以及三色等比例输出的合成与色散,同时也可以演示不等比例的输出,调节不同颜色单色光的亮度从而合成其他颜色。可以用于课堂演示教学,是一个简易而有效的教具。 相似文献
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在演示文稿中使用声音、视频、Flash动画等外部素材,可以极大地丰富演示文稿的展示效果,提高演示文稿的交互性。本文介绍在PowerPoint2003中使用多媒体对象的方法和技巧。 相似文献
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牛顿第一运动定律在教材中没有安排演示实验,而通常的演示大多是在气垫导轨上进行.我们设计该演示实验不仅可以取代气垫导轨,而且取材容易,操作简单,可见度大,还可在任意方向上演示第一定律,克服了在气垫导轨上演示的固有缺点.具体介绍如下. 相似文献
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受迫振动与共振实验的创新设计 总被引:1,自引:1,他引:0
利用变频器、同步电动机和磁性书写板来改进受迫振动与共振演示实验装置.本装置可以用来定量演示受迫振动,还可以用来研究共振的发生条件及描绘共振曲线. 相似文献
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在中学物理教学中,有部分演示实验需要用到两用气筒或抽气机,若没有以上仪器,可以用医用玻璃注射器来替代.它装置简单、密封性能好、使用方便、演示效果明显.对仪器设备缺乏的学校,只要购买两只大小不同的注射器,就可以用来作代用仪器完成很多中学物理演示实验.下面介绍几例应用注射器来进行的物理演示实验供大家参考. 相似文献
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化妆品中草药添加剂的光谱特性研究 总被引:3,自引:0,他引:3
中草药作为化妆品天然添加剂 ,既能保持化妆品的特色 ,又有养护、保健和治疗的效果。某些中草药具有吸收紫外线的功能 ,而且有修复晒伤的作用。文章主要用紫外 可见分光光度计测定化妆品几种中草药添加剂的光谱特性 ,分析其对紫外光的吸收作用。说明野生绞股蓝对紫外光有较好的吸收作用 ,完全可以作为较好的防晒和保健化妆品的天然添加剂 ;党参、野菊花、黄芩和甘草对紫外光也有一定的吸收作用 ,可以作为一般化妆品的天然添加剂。川芎对紫外光吸收较差 ,不能作为防晒添加剂。 相似文献
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Stimulated Brillouin scattering is studied by numerically solving the Vlasov-Maxwell system. A cascade of stimulated Brillouin scattering can occur when a linearly polarized laser pulse propagates in a plasma. It is found that a stimulated Brillouin scattering cascade can reduce the scattering and increase the transmission of light, as well as introduce a bursting behaviour in the evolution of the laser-plasma interaction. The bursting time in the reflectivity is found to be less than half the ion acoustic period. The ion temperature can affect the stimulated Brillouin scattering cascade, which can repeat several ×at low ion temperatures and can be completely eliminated at high ion temperatures. For stimulated Brillouin scattering saturation, higher-harmonic generation and wave-wave interaction of the excited ion acoustic waves can restrict the amplitude of the latter. In addition, stimulated Brillouin scattering cascade can restrict the amplitude of the scattered light. 相似文献
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任意相位差条纹信号细分方法的研究 总被引:5,自引:0,他引:5
为消除传统细分方法中由于两路条纹信号不正交引入的细分误差,提出了一种可对任意相位差条纹信号直接细分的新方法。根据两路条纹信号的极性和幅值大小,把一个信号周期分成8个区段。高速采集两路条纹信号,通过判断信号采样点所处的区段是否跳变对信号幅值交点进行动态跟踪。对不足一个周期的条纹移动,当测量出起点与终点的幅值,计算出其所在的区段及位置后,结合两路信号的交点,可实现对任意相位差条纹信号的细分。实验结果表明,该方法突破了传统细分方法必须信号正交的限制,可对任意相位差信号进行准确地细分,降低了条纹测量中器件安装与调试的难度,具有更强的环境适应性和抗干扰能力。 相似文献
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Douglas Poland 《Journal of statistical physics》1990,61(3-4):765-802
The coefficients in power series in the variable time that describe relaxation in a cooperative system can be calculated using a combinatorial approach where one considers how many ways one can introduce a given number of properly defined events in a system. The coefficients obtained in this manner can be related to the equilibrium virial coefficients for a mixture. If one assumes rapid internal equilibration, the relaxation process can be expressed completely in terms of the viral coefficients for a mixture with at most one solute particle, or, in some cases, just the virial coefficients for a single-component system. Thus, equilibrium virial coefficients can give useful information about the time evolution of processes in cooperative systems. 相似文献
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光学技术在运动人体科学中的应用 总被引:1,自引:0,他引:1
研究了光学技术在人体运动研究中潜在应用.光生物调节作用可以抑制细胞凋亡.色光疗法、低强度激光针灸和鼻腔内低强度激光照射可以调节植物神经功能和昼夜节律,它们具有防治运动性疲劳的潜在价值.蛋白质分子构型变化可以用园二色谱表征,组织和大脑血氧饱和度的变化可以用近红外光谱表征,尿液可以用傅里叶红外光谱进行代谢组学研究,它们都可以作为运动训练的有效表征工具. 相似文献
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The ion motion in the presence of linear polarized Affvdn waves is studied. For a linearly polarized wave, nonlinear resonances can occur when the amplitude of Alfven wave is large enough. Under certain conditions, these resonances can overlap and thus make the ion motion chaotic. In this process, the plasma can be heated without the limitation of cyclotron resonant condition. Taking into account of a spectrum of waves, the stochastic condition can decrease largely. In addition, the preferential heating can be found in the perpendicular direction. 相似文献
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We study three critical curves in a quasiperiodically driven system with time delays, where occurrence of symmetry-breaking and symmetry-recovering phenomena can be observed. Typical dynamical tongues involving strange nonchaotic attractors (SNAs) can be distinguished. A striking phenomenon that can be discovered is multistability and coexisting attractors in some tongues surrounding by critical curves. The blowout bifurcation accompanying with on-off intermittency can also be observed. We show that collision of attractors at a symmetric invariant subspace can lead to the appearance of symmetry-breaking. 相似文献
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Gennadiy Burlak Svetlana Koshevaya Masashi Hayakawa Edmundo Gutierrez-D Vladimir Grimalsky 《Optical Review》2000,7(4):323-325
It is shown that the deceleration of light pulses down to the velocity of a sound value can be realized in a case of unidirectional parametric interaction of two electromagnetic waves with an acoustic one in the regime of forming three wave acousto-optic solitons. This nonlinear acousto-optic interaction can be realized in long distance systems like fibers. As the result of such an interaction, two types of acousto-optic envelope solitons can propagate in fibers. Modulation of the amplitude of the electromagnetic pump wave can control the soliton velocity. 相似文献