共查询到19条相似文献，搜索用时 171 毫秒
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姜宇驰 《常熟理工学院学报》2011,25(2):39-41
利用依赖于频率的时域有限差分法（FD）2TD计算了入射平面波波长分别为355nm和800nm情况下,从四面锥尖底面入射和侧面入射时锥尖所在平面光增强大小,并对结果进行了比较和分析.结果表明,较大波长的入射光从锥底面入射时能够获得较大的光增强和纳米尺度的光斑. 相似文献
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当频率相同、振动方向相同、相位差恒定的两束简谐光波相遇时,在光波重叠区域,形成强弱相问的稳定分布,这种现象称为光的干涉。日常生活中能见到诸如肥皂泡呈现的五颜六色,雨后路面上油膜的多彩图样等,都是光的干涉现象。光的干涉现象在科学研究和丁业生产上有着广泛的应用,如测量光波波长、精确地测量微小物的长度、厚度和角度,检验物体表面光洁度等。下面我谈谈劈尖干涉存物理中的应用。 相似文献
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基于MATLAB的牛顿环的模拟研究 总被引：1，自引：0，他引：1
根据光的干涉理论,利用MATLAB强大的科学计算功能,对牛顿环进行模拟,并通过动画形式展现了入射光波长、透镜半径及透镜与平面玻璃板间距离变化时牛顿环的移动方向,结果表明:该模拟简便、直观地展现了这一物理现象,为光学的理论分析与实验教学提供了方便. 相似文献
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王志强 《数理化学习(高中版)》2003,(5)
圆心在原点O,半径等于单位长度的圆叫做单位圆,现列举它在平面三角中的重要应用,供同行参考. 1.三角函数的几何表示——三角函数线新教材(试验修订本·必修)高一《数学》第一册(下)(以下简称《数学》)第14页介绍了正 相似文献
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《中学数学教学参考》2007,(9)
《全日制普通高级中学教科书(必修)数学》第二册(下)第九章"直线、平面、简单几何体"中,在已经推导过球的体积公式的基础上,对球的表面积公式用如下方式进行了推导.(1)分割.把球 O 的表面分成 n 个小网格,设它们的表面积分别是△S_1,△S_2,…,△S_n,则球的表面积 S=△S_1 △S_2 … △S_n.把球心 O 和各小网格的顶点相连,则整个球体被分割成 n 个"小锥体",每个"小锥体"的底面是球面的一部分.(2)求近似和.设 n 个"小锥体"的体积分别是 相似文献
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曲恒绪 《佳木斯教育学院学报》2012,(5):417-418
对水泥筒仓在减压锥高度范围内的贮料压力进行了分析,证明在实际使用过程中锥体所受的荷载明显大于设计承载力,而按锥底深度计算出来的贮料压力是最大的。 相似文献
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《开封教育学院学报》1998,(2)
光的干涉、光的衍射是光学课程中两个最重要的内容。而杨氏双缝干涉实验,夫琅禾费单缝衍射又是光的干涉、光的衍射中的两个最基本问题.在研究杨氏双缝干涉实验时,干涉图样的条纹间距与入射光波长、缝间距离、观察屏和缝的距离都有关系.对夫琅禾费单缝衍射,当入射光的波长及狭缝宽度给定以后,衍射图样条纹间距与透镜焦距f成正比. 相似文献
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《实验室研究与探索》2015,(10):44-46
为了提高硅太阳能电池的效率,研究了入射光波长对硅太阳能电池表征参数的影响。实验中采用恒定功率的白炽灯为光源,经过不同的滤光片后得到不同波长的光,测定了在不同波长的入射光照射下硅太阳能电池表征参数的变化。结果表明,随入射光波长的增大,硅太阳能电池的开路电压、短路电流、最大输出功率和填充因子都逐渐增大。实验过程中还发现,在入射光波长436 nm时,硅太阳能电池表面的氮化硅增透膜对硅太阳能电池表征参数产生的影响较大。 相似文献
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In this paper,a model named fictitious soil pile was introduced to solve the boundary coupled problem at the pile tip.In the model,the soil column between pile tip and bedrock was treated as a fictitious pile,which has the same properties as the local soil.The tip of the fictitious soil pile was assumed to rest on a rigid rock and no tip movement was allowed.In combination with the plane strain theory,the analytical solutions of vertical vibration response of piles in a frequency domain and the corresponding semi-analytical solutions in a time domain were obtained using the Laplace transforms and inverse Fourier transforms.A parametric study of pile response at the pile tip and head showed that the thickness and layering of the stratum between pile tip and bedrock have a significant influence on the complex impedances.Finally,two applications of the analytical model were presented.One is to identify the defects of the pile shaft,in which the proposed model was proved to be accurate to identify the location as well as the length of pile defects.Another application of the model is to identify the sediment thickness under the pile tip.The results showed that the sediment can lead to the decrease of the pile stiffness and increase of the damping,especially when the pile is under a low frequency load. 相似文献
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In this paper,a model named fictitious soil pile was introduced to solve the boundary coupled problem at the pile tip.In the model,the soil column between pile tip and bedrock was treated as a fictitious pile,which has the same properties as the local soil.The tip of the fictitious soil pile was assumed to rest on a rigid rock and no tip movement was allowed.In combination with the plane strain theory,the analytical solutions of vertical vibration response of piles in a frequency domain and the corresponding semi-analytical solutions in a time domain were obtained using the Laplace transforms and inverse Fourier transforms.A parametric study of pile response at the pile tip and head showed that the thickness and layering of the stratum between pile tip and bedrock have a significant influence on the complex impedances.Finally,two applications of the analytical model were presented.One is to identify the defects of the pile shaft,in which the proposed model was proved to be accurate to identify the location as well as the length of pile defects.Another application of the model is to identify the sediment thickness under the pile tip.The results showed that the sediment can lead to the decrease of the pile stiffness and increase of the damping,especially when the pile is under a low frequency load. 相似文献
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Zhou-yan Feng Xiao-jing Zheng Jing Wang 《Journal of Zhejiang University. Science. B》2009,10(7):505-511
Objective: To directly examine the effects of carnosine on neuronal excitation and inhibition in rat hippocampus in vivo. Methods: Artificial cerebrospinal fluid with carnosine was directly administrated over the exposed rat hippocampus. The changes of neuron activity in the CA1 region of hippocampus were evaluated by orthodromically- and antidromically-evoked potentials, as well as paired-pulse stimulation paradigm. Results: In both orthodromic and antidromic response potentials, carnosine transformed population spikes (PSs) with single spike into epileptiform multiple spikes. In addition, similar to the effect of γ-aminobutyric acidA (GABAA) antagonist picrotoxin, carnosine decreased paired-pulse stimulating depression significantly.However, no significant change was observed in the spontaneous field potentials during the application of carnosine. Conclusion:The results indicate a disinhibition-induced excitation effect of carnosine on the CA1 pyramidal neurons. It provides important information against the application of carnosine as a potential anticonvulsant in clinical treatment. 相似文献
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王万录 《重庆大学学报(英文版)》2003,2(2)
1. Introduction Recently, carbon nanotubes have attracted a lot of interest because of their outstanding electrical properties and their potential application as a possible material for fabrication of cold cathodes [1-3]. It was found that the field enhancement from carbon nano-tubes exhibited large local field enhancement and considerable field emission currents at relatively low applied voltage. Carbon nanotube-based field emission displays have been fabricated using well-aligned nano-tubes … 相似文献
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通过分析正弦波、方波和最优化过零方波作为激励信号源的优点和不足,设计了集合这三种激励信号源优点的优化过零梯形波,以满足主动型邻井定位技术的测距范围和精度需要。同时提出了基于优化过零梯形波信号源的多频信号检测算法:首先,把接收端的三频含噪信号进行DFT算法处理,找出三个最大幅值对应的频率,求出对应频率的恢复信号幅值;其次,进行幅值校正得到三个频率原始激励信号的真实幅值;最后,对计算出的每个信号的频率及幅值进行重新构造,得到重构信号。仿真实验表明,优化过零梯形波的基波能量占比接近于正弦波,高于最优化过零方波,便于其扩大测距范围、增加测距精度,而且优化过零梯形波作为激励信号源容易在工程上实现。 相似文献
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为实现便捷、可靠的日常婴儿心率实时监测,提出一种基于面部图像的非接触式婴儿心率实时监测方法。首先引入欧拉视频放大技术,对一定时间间隔内视频的每一帧图像进行颜色增强处理,从而改善婴儿面部颜色变化微弱、所含心率信息不明显的问题;然后,通过Adaboost算法从每一视频帧中识别出婴儿面部,并从婴儿面部选取脸颊区域作为敏感区域以提取脉搏波信号,以此为基础提出一种改进的反射光强模型,抑制日间因环境光变化引起的干扰以及运动噪声干扰,提高脉搏波信号信噪比;此外采用摄像头的红外自主光源,通过一种基于相空间重构的单通道独立成分分析法分离夜间脉搏波信号的运动噪声,解决因夜间光照条件差引起的婴儿心率监测困难的问题;最后开发整个系统上位机应用程序,并通过实验验证该方法正确性和有效性。 相似文献
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电液耦合喷印技术具有分频特性,可进行按需喷印,并应用于微机电器件的制造。使用有芯喷头,则有助于实现高分辨率喷印。由于针芯尖端存在大曲率、强电场,使得溶液沿针芯尖端喷射。讨论了喷管内径、针芯伸出长度、喷管至收集板间距对脉冲喷印的影响。当喷管内径减小、针芯伸出长度缩短、喷管至收集板距离增加,针芯尖端处单次喷射的溶液量减少,因而溶液沉积频率更容易趋向于电压频率。同时,大曲率针芯尖端决定了溶液喷射的上极限电压,以避免击穿电场空间;而喷管尺寸及其至收集板板距离决定了溶液喷射的下极限电压,以满足喷管末端悬滴表面流的产生条件。 相似文献
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刘文海 《咸阳师范学院学报》2006,21(5):87-88
风景写生色彩是使用科学原理,通过分解得到波长不同的光波反射到人的眼睛,再经过心理反应运用各种绘画媒介和语言将这种有色光传达在二维空间中的过程。这个过程既离不开理性的分析,也少不了感性的表现。 相似文献