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1.
蔡军  刘绍军 《计算物理》1999,16(2):128-134
给出一个简单解析的嵌入原子势模型。该模型被用于计算FCC金属的声子谱,表面驰豫,结构稳定性和总能曲线,计算结果与实验及更高水平的计算结果进行了比较。  相似文献   

2.
CCD输出信号处理   总被引:20,自引:1,他引:19  
根据CCD的工作原理,从分析CCD输出信号特征出发,简要介绍一种用于降低CCD图像噪声的常用方法,即相关双取样方法。并对电路的实现和实验结果进行分析和讨论。  相似文献   

3.
本文提出了一种与计算机技术相结合、利用CCD像感器件测定变折射率透镜阵列传递函数的方法,该方法比较接近于变折射率透镜阵列有实际使用环境,精确度高,测量速度快,而且简便易行,测量结果也较为全面。该方法已用于光电图文扫描仪中变折射率透镜阵列的设计及测量,并获得了满意的结果。  相似文献   

4.
本文设计了一种模拟焊接操作的训练系统。它由激光准直系统、CCD投影成像系统和焊接定位系统组成。该系统利用线阵CCD确定焊枪距离焊口的高度,利用桥式电路确定焊枪水平方向移动的位置,实时描绘出焊枪在移动过程中高度随水平位置变化的曲线,模拟出焊接操作的实时情况。  相似文献   

5.
随着计算机技术的发展;将个人计算机应用于气动分析和实时设计已经变得可行。近些年来,由于其优越的特性,Bezier曲线在CAD/CAM当中的应用变得越来越广泛。在这篇论文里,介绍了一种利用Bener曲线来生成压气机子午流道,具有人机对话界面的设计分析软件。利用此软件进行设计,具有快速直观的特点,能够有效的提高设计者的工作效率。  相似文献   

6.
用于光纤电流传感器的BGO晶体磁光特性研究   总被引:1,自引:1,他引:0  
在理论分析Bi4Ge3O12(BGO)晶体磁光特性的基础上,利用倍频法测量了不同工作波长下BGO晶体的费尔德常量,获得了与理论相符的实验结果.同时根据BGO晶体费尔德常量随波长的变化关系曲线,通过对该晶体吸收系数的测量,得出了其磁光优值曲线.进而将BGO晶体的磁光特性与光纤电流传感器常用的几种磁光材料作了对比,结果表明BGO晶体适合用于光纤电流传感器.  相似文献   

7.
苏衡  杨方正 《光学学报》1996,16(6):53-856
用简易易行的方法对液晶光阀(LCLV)的工作特性曲线作了测量,包括光阀在正像,反转像和微分像状态读出光强与写入光强的响应曲线,以及不同写入光照度下液晶层透过率与工作电压的关系曲线,对所得结果的分析揭示了这方面以及未曾深入研究的液晶光阀非线性转换的特性,由此为光阀的很多新用途提供了坚实的实验基础,指出了进一步探索的方向。  相似文献   

8.
本文综述了用于空间飞行器交会对接的CO_2相干激光雷达系统的功能、设计及工作原理,并提出了用于我国空间飞行器自主交会对接的CO_2相干激光雷达的技术方案。初步研究表明,所设计的CO_2相干激光雷达用于空间飞行器交会对接中测量目标的距离及姿态是可行的。  相似文献   

9.
本文介绍了国产7503B型光电直读光谱仪用于分析炉前熔清钢水中磷元素成分的一种方法,选择和确定了最佳工作条件,校准曲线和控制样品,此方法快速,准确,分析结果令人满意。  相似文献   

10.
在前期工作的基础上,对非对称几何条件下波函数中的索末菲参量作了进一步的完善。研究了索末菲参量对三重微分截面(TDCS)产生的影响。用新的索末菲参量计算了低能电子入射离化氢原子的TDCS。所得结果与前期工作及CCC理论结果进行比较发现:所得结果明显地改善了理论曲线与实验数据的符合程度。  相似文献   

11.
 用射频磁控溅射方法得到了低应力立方氮化硼薄膜。红外光谱结果表明,薄膜具有很好的附着力,且含有少量的E-BN和w-BN。电子衍射谱表明薄膜表层是纯立方相。同时利用此方法得到了E-BN薄膜。认为在薄膜生长过程中可能经历了一个从E-BN到c-BN的相转变过程。  相似文献   

12.
张晓丹  刘翔  赵品栋 《物理学报》2009,58(7):4415-4420
提出了一种计算延迟混沌系统沿主轴方向上Lyapunov指数的方法:矩阵迭代法.给出了其计算方法的原理及推导过程;同时推导了一类泰勒展开法,介绍了已有的Wolf替代法计算延迟混沌系统的Lyapunov指数.分析了三种不同计算方法的优缺点,最后进行了数值模拟,验证方法的有效性. 关键词: Lyapunov指数 延迟混沌系统 矩阵迭代法 泰勒展开法  相似文献   

13.
Ling-fei Xu  Wusen Li  Meng Zhang  Shi-xue Xu  Jia Li 《Optik》2011,122(7):594-598
In the common basic oxygen furnace technique, we often get the information of furnace flame by our eyes, from which we could estimate the content of the carbon in the molten iron. In order to using an optical device to estimate the end point of BOF accurately, we design an arithmetic to predict the end point. The variety of the furnace flame essentially is the variety of the spectrum. So we proceed with the variety of spectrum distributing, distilling some parameters which could depict the variety of spectrum, combining with the support vector machine (SVM) to compose a system which could predict the end point of BOF relatively accuracy. The result of the experiment shows that the model meets the requirements of end-point judgment online. Furthermore, by discussing with the different output function of SVM, we can confirm that we can measure the content of carbon in the molten iron in real time by using this model.  相似文献   

14.
The seismic data inversion from observations contaminated by spurious measures (outliers) remains a significant challenge for the industrial and scientific communities. This difficulty is due to slow processing work to mitigate the influence of the outliers. In this work, we introduce a robust formulation to mitigate the influence of spurious measurements in the seismic inversion process. In this regard, we put forth an outlier-resistant seismic inversion methodology for model estimation based on the deformed Jackson Gaussian distribution. To demonstrate the effectiveness of our proposal, we investigated a classic geophysical data-inverse problem in three different scenarios: (i) in the first one, we analyzed the sensitivity of the seismic inversion to incorrect seismic sources; (ii) in the second one, we considered a dataset polluted by Gaussian errors with different noise intensities; and (iii) in the last one we considered a dataset contaminated by many outliers. The results reveal that the deformed Jackson Gaussian outperforms the classical approach, which is based on the standard Gaussian distribution.  相似文献   

15.
The behavior of geodesic curves on even seemingly simple surfaces can be surprisingly complex. In this paper we use the Hamiltonian formulation of the geodesic equations to analyze their integrability properties. In particular, we examine the behavior of geodesics on surfaces defined by the spherical harmonics. Using the Morales-Ramis theorem and Kovacic algorithm we are able to prove that the geodesic equations on all surfaces defined by the sectoral harmonics are not integrable, and we use Poincaré sections to demonstrate the breakdown of regular motion.  相似文献   

16.
We review our recent efforts on power scaling of THz pulses generated from several nonlinear-optical crystals. By using a high-resistivity GaP crystal, we have significally increased the output peak power to as high as 722 W. By stacking three GaP wafers, we have further increased the highest output peak power to 2.36 kW. On the other hand, by using CO2 laser pulses, we have obtained the average output power of 260 μW. We have also used these laser pulses to scale up the output power for the THz pulses to 29.8 μW by stacking GaAs wafers. Indeed, by stacking up to ten wafers, we have increased the output power by a factor of 160. Finally, by using ultrafast laser pulses, we have achieved record-high output powers for the THz pulses generated from multi-period periodically-poled LiNbO3 crystals based on a backward configuration. The highest output power obtained by us so far is 10.7 μW.  相似文献   

17.
In this paper we demonstrate experimentally the intra-cavity generation of a coherent superposition of Laguerre–Gaussian modes of zero radial order but opposite azimuthal order. The superposition is created with a simple intra-cavity stop that creates equal losses for the two azimuthal modes, and we show that by adjustment of the stop we can produce modes up to azimuthal order 8. The fact that we have a coherent superposition rather than an incoherent superposition is verified by intensity measurements, propagation measurements and a decomposition of the field by an inner product executed on a phase-only spatial light modulator. Such fields have relevance in quantum information and optical trapping.  相似文献   

18.
There are two physical phenomena in a strong laser intensity. One is the high-order harmonic emission; the other is x-ray emission from optical-field ionized plasmas. The experiment of conversion from high-order harmonics to x-ray emissions was given with a 105fs Ti:sapphire laser by adjusting laser intensities. The ingredient in plasma was investigated by the numerical simulations.Our experimental results suggested that the free electrons have detrimental effects on harmonic generation but are favourable for x-ray emission from optical-field ionized plasmas. If we want to obtain more intense harmonic signals as a coherent light source in the soft x-ray region, we must avoid the production of free electrons in plasmas. At the same time, if we want to observe x-rays for the development of high-repetition-rate table-top soft x-ray lasers, we should strip all atoms in the plasmas to a necessary ionized stage by the optical-field-ionization in the field of a high-intensity laser pulse.  相似文献   

19.
Using a semiclassical approach, we analyze the collective behavior of neutrinos and antineutrinos in a dense background. Applying the Wigner transform technique, we show that the interaction can be modeled by a coupled system of nonlinear Vlasov-like equations. From these equations, we derive a dispersion relation for neutrino-antineutrino interactions on a general background. The dispersion relation admits a novel modulational instability. Moreover, we investigate the modifications of the instability due to thermal effects. The results are examined, together with a numerical example, and we discuss the induced density inhomogeneities using parameters relevant to the early Universe.  相似文献   

20.
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