共查询到20条相似文献,搜索用时 890 毫秒
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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
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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
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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
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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
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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
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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
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Suzane A. Silva Srgio Luiz E. F. da Silva Renato F. de Souza Andre A. Marinho Joo M. de Araújo Claudionor G. Bezerra 《Entropy (Basel, Switzerland)》2021,23(8)
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
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Thomas J. Waters 《Physica D: Nonlinear Phenomena》2012,241(5):543-552
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
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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
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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
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提出了一种大口径干涉仪标准镜绝对面形精度的传递方法,在已知一台干涉仪参考镜绝对面形的前提下,可向待测标准镜进行精度传递。由于检测温度与使用温度的不同,待测标准镜在另一台干涉仪作参考镜时,绝对面形会发生变化,变化集中在离焦量上;在待测标准镜使用状态下,通过对经典三板互检法得到的竖直方向直线绝对面形的分析,得到标准镜使用状态离焦量的估计,以此修正直接精度传递结果,最终得到待测标准镜使用状态下的绝对面形。比较同一块光学元件在两台干涉仪上标定前和标定后的测量结果,标定后的面形差值更小且分布一致性更好,证明了本方法的有效性和可行性。 相似文献
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Modal prediction for closed-loop adaptive optics 总被引:1,自引:0,他引:1
The correction efficiency of adaptive optics is limited mainly by measurement noise and time delay. To overcome this problem, we describe a new modal linear predictive controller whose parameters are optimized by means of a recursive least-squares algorithm to minimize the residual optical phase variance. The method copes with the recursivity of the closed-loop operation. We demonstrate that the optimal rejection transfer function for adaptive optics is proportional to the frequency signal-to-noise ratio. Finally, we present what we believe to be the first experimental results obtained with a predictor used to control the tip-tilt mirror of an adaptive-optics system. 相似文献
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One difficulty with adiabatic quantum computation is the limit on the computation time. Here we propose two schemes to speed-up the adiabatic evolution. To apply this controlled adiabatic evolution to adiabatic quantum computation, we design one of the schemes without any explicit knowledge of the instantaneous eigenstates of the final Hamiltonian. Whereas in another scheme, we assume that the ground state of the Hamiltonian is known, and this information can be used to design the control. By these techniques, a linear speed-up proportional to the nonlinearity can be predicted. As an illustration, we study a two-level system driven by a time-dependent magnetic field under the control. The problem of finding an item in an unsorted database by adiabatic evolution is also examined. The physics behind the control scheme is interpreted. 相似文献