二维分布
- 与 二维分布 相关的网络例句 [注:此内容来源于网络,仅供参考]
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Based on the Navier-Stokes equations in conservative form derived with respect to nonorthogonal curvilinear coordinates and nonorthogonal velocity components, the numerical method for solving 3D viscous flow has been discussed.
本文基于非正交曲线坐标与相应的非正交速度分量下导得的守恒型N—S方程,讨论了求解三维粘性流动的数值方法,计算中显式时间推进算法与Baldwin—Lomax湍流模型被采用,应用本工作发展的程序,作为算例计算了一个沿径向非等截面环形叶栅的三维粘性流场,得到了诸如三维压力分布,总压损失分布以及十分清晰的二次流动图景等丰富的流场信息。
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The influences of the shock thickness and Alfven waves on the particle acceleration by diffusive shock waves are numerically studied through solving one-dimensional diffusive equation including the second-order Fermi effect. It is shown that the spectral index of the energetic particles strongly depends on the shock thickness. For example, the spectral index increases from 2.1 to 3.7 in the low energy range of 3-10 MeV and from 2.5 to 5.0 in the high energy range of 20-60 MeV as the thickness increases. The spectral index decreases from 4.3 to 3.1 as the particle injection energy increases. The spectral index decreases from 4.0 to 1.8 at the quasi-steady stage with the enhancement of the compression ratio from 2 to 4. The results indicate that under the influence of Alfven waves, the energetic particle spectrum at lower energy becomes flat and the spectral index decreases from 2.5 to 0.6 in the low energy range of 3-10 MeV and from 11.6 to 5.0 in the high energy range of 20-60 MeV. At the same time, the rollover energy reaches 19.6 MeV. The spectral index decreases from 5.8 to 2.9 as the energy density of Alfven waves increase. All these results are basically consistent with the theoretical models, as well as the observations of typical energetic particle events.
通过数值求解包含二阶费米加速的一维扩散方程,探讨在准平行激波条件下激波厚度和级联阿尔芬波对粒子加速的影响,研究粒子分布函数的演化与激波厚度和阿尔芬波强度的内禀关系,计算结果表明:(1)考虑激波厚度时,谱指数明显依赖于激波厚度,随着厚度从0.32增大到2.56,低能端(3-10MeV)谱指数逐渐从2.1增加到3.7,高能端(20-60MeV)谱指数从2.4增大到5.0,能谱逐渐变软;当初始注入粒子动量增大1.3倍,质子能谱指数从4.3减小到3.1,且与零厚度激波加速的谱指数差值缩小;厚度不变时,随着压缩比从2增加到4,准稳态分布时低能端(3-10MeV)粒子能谱指数逐渐从4.0减小到1.8谱变硬;(2)在级联阿尔芬波的影响下,随着时间的增大,粒子在低能处(3-10MeV)的谱指数从2.5减小到0.6高能端(20-60MeV)谱指数从11.6减小到5.0,能谱变硬,拐点能量值从7.5MeV增大到为19.6MeV;随着波的能量密度增大,谱指数从5.8减小到2.9,这表明阿尔芬波强度越大,加速效率越高,通过与激波厚度解析结果和高能粒子事件的观测能谱比较发现两者是一致的,说明数值模拟结果是可靠的。
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In this chapter, three kinds of target recognition methods are performed, which are:①Target recognition method based on the description of polarization parameter plane. The echo polarization states of target are projected onto the polarization state plane described by the ellipticity ε and the tilt angle τ of the polarization ellipse, the change of parameter following ferquency becomes the chart. According to the changing trait of the chart, the multidimensional polarization feature space of target has been contructed. Furthermore, a series of polarization feature parameters used in designing the structure of target recognition device are extracted, and they are insensible to the posture of target.②Target recognition method based on the description of Poincare polarization sphere. The echo polarization states of target expressed by Stokes vector are projected onto the Poincare polarization sphere. The conception of polarization ferquency stability, which is used in describing the dynamic distribution characteristics of the target echo polarization states on Poincare polarization sphere, has been defined. A group of polarization feature parameters used in designing the structure of target recognition device are extracted, and they are insensible to the posture of target.③Target recognition method based on the description of frequency sensitivity. In accordance with the conception of the polarization state distance defined on Poincare polarization sphere, the frequency sensibility of the physical structure property of target has been investigated, the frequency distribution feature curves in PSD domain are obtained, and targets'features are extracted by means of the curve-fitting method with Least Square Criterion.
这章具体研究了基于三种极化散射特性描述的相应的目标识别方法:①基于极化参数平面描述的目标识别方法,将目标回波极化状态投影到以极化椭圆参数,即椭圆率角ε和倾角τ表征的极化状态平面上,参数随观测频率的变化就形成了图,根据图的变化特点构造了目标的多维极化特征空间,并提取了不敏感目标姿态变化的极化特征参数组来设计目标的识别器结构;②基于Poincare极化球面描述的目标识别方法,采用Stokes矢量表征目标回波的极化状态,并将其投影到描述极化状态的Poincare极化球面上,定义了极化频率稳定度的概念用以刻画目标回波极化状态在Poincare极化球面上的动态分布信息,提取了准方位不变性的目标极化特征,最后设计了目标的识别器结构;③基于频率敏感性描述的目标识别方法,通过在Poincare极化球面上所定义的极化状态距离的概念,研究的是复杂目标物理结构特性对探测信号频率的敏感程度问题,获得了在极化状态距离下的频率分布特性曲线,采用最小二乘估计曲线拟合方法,它既用于极化特征的降维,同时又直接将拟合参数作为目标的分类特征。
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Icosehedral quasicrystal, showing icosahedral point group symmetry and quasi-periodic order along three directions, has been intensively studied.
二十面体准晶是目前研究最广泛的准晶之,它具有二十面体点群对称性,属于三维准晶,就是说其原子在三维上都是准周期分布的。
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Basing on the analysis of 1 dimension observation,2 dimensions and 3 dimensions points confidence region,a general formular is proposed in this paper,which can be used to calculate the semidiameter of P dimensions super space ellisposid by using some important probability distributions.
在分析一维观测量、二维和三维坐标点置信区间、区域的基础上,利用几个重要的数学分布,导出了线、面这一p维随机向量的置信区域——p维超空间误差椭球半径的计算公式,同时应用实例验证了该通式与常规公式的一致性。
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With the theoretical model of spherical grain dynamics of sparse two-phase flow in single dimension, computing formulas of velocity′s attenuation and scattering distance were built for explosive residue grains in horizontal. Then, a simplified theoretical model on distribution of explosive residue was put forward on the basis of a spherical space with radius equalling to maximum horizontal scattering distance of explosive residue grains with certain diameter.
为了对残留物颗粒的飞散运动及分布规律进行理论分析,利用球形颗粒一维稀疏二相流动力学模型,研究得到炸药残留物颗粒的速度衰减及水平飞散距离计算公式;在此基础上,建立了以某粒径残留物颗粒水平运动极限距离为半径的炸药残留物颗粒球面空间分布简化理论模型。
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This paper addresses the relationship between multispectral satellite information and probed relative humidity in each of standard isobaric surfaces using correlation analysis, least-square fitting and multivariate linear regression separately.
多光谱卫星图像上不同云类的云层高低分布蕴涵着三维湿度场的分布信息,文中用相关分析、最小二乘拟合分析和多元线性回归分析分别讨论了多光谱卫星信息与各标准层相对湿度的关系。
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Relation and Application of Density and Compression Strengh of Effervescible Polystyrence Foam Material;2. On the basis of discussing principle of foam material cell shape,this research studied two methods to measure cell diameter and its distribution,which are picture process and fractal dimension.
探讨了泡沫材料泡孔结构形成原理及泡沫材料孔径与分布测量途径,并实际运用图像处理和分维二种创新的测量方法对泡孔进行测量分析,其二结果相当一致,从而证实了图像法与分维法的可行性,同时说明了分维的科学性。
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In this paper, based on a pill-box window model with a conical-shaped alumina ceramic and Ansoft HFSS software, the relation of VSWR with various electrical parameters in the window is simulated; the effects of variations of the output window structure on electrical field intensity, microwave power flow and quantity of heat are analyzed; the electrical characteristics of frequency bandwidth, power capability and heat dissipation for the pill-box window with conical-shaped or disk alumina ceramic are discussed, which shows that, with a rational structure of the window with conical-shaped alumina ceramic, the output capability of microwave peak and average power may greatly be increased, the secondary electron emission may effectively be suppressed, and heat dissipation may become more uniform and be easier for cooling.
本文在前人工作的基础上,基于圆锥形陶瓷盒形输出窗模型,采用Ansoft HFSS三维计算软件的优化模拟,对该输出窗模型的驻波频率特性与各种结构参量的关系进行了优化模拟,分析了该输出窗片结构变化对其表面的电场分布,功率流分布、热量分布的影响,得出最优模型参数。并且探讨了陶瓷窗片的形状和几何结构对改善输出窗的频带特性、提高峰值功率和平均功率、抑制二次电子倍增方面的作用。
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Small signal solution of aberrated second harmonic generation is deduced from three-dimension three wave coupling functions. The numerical work gives out lot of results of different aberrations. The effects of the fundamental wave's aberrations, which will change the conversion efficiency, distribution of intensity and phase in the frequency conversion, is analyzed. It shows that when walk-off and diffraction effects could be ignored approximately estimation of the phase distribution of second-harmonic wave could be done. The far field divergent angle and second moment radius of harmonic wave will vary with the aberration of fundamental wave, but the far field divergent angle will be obviously smaller than that of fundamental wave. The phase distribution of both fundamental and harmonic wave is measured using Hartmann-Shack wave front sensor in the experiment with 1064nm and 790nm lasers, respectively. Results are given.
首次从三维三波相互作用方程组推导得到了位相畸变光束倍频的小信号解;通过建立三维数值模型,编写相应仿真程序,首次得到了位相畸变光束倍频过程的大量计算结果,深入细致地研究了位相畸变光束经非线性光学频率变换后谐波的转换效率、光强分布、位相分布以及影响它们的各种因素;得出谐波的远场发散角和光斑二阶矩的变化规律会因为基波像差的不同而不同,但谐波的远场发散角明显地比相应基波的小的结论;得到了在走离效应和衍射效应等影响许多因素可以忽略的情况下,位相畸变传递到二次谐波的估算式;举例分析了KDP三倍频方案中,基波位相畸变对二次谐波和三次谐波的影响;实验工作中,用哈特曼-夏克传感器分别对1064nm倍频过程和790飞秒超短脉冲倍频过程中的基波和谐波的位相分布进行了测量,给出了相应结果。
- 推荐网络例句
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She gently rebuff ed him, but agreed that they could be friends
她婉言拒绝了,但同意作为朋友相处。
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If in the penal farm, you were sure to be criticized.
要是在劳改农场,你等着挨绳子吧!
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Several theories about reigniting and extinguishing of the arc have been refered.
本文综合考虑了几种电弧重燃和熄灭理论。