共查询到20条相似文献,搜索用时 125 毫秒
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本文简要介绍在对扩散杂质分布作了近似之后(在发射区和基区漂移场加速区中近似为 指数型分布,而发射结区和基区漂移场减速区中近似为线性分布),计算了双扩散晶体管的基 区输运系数、基区渡越时间和注射效率.在讨论中着重指出,为了减小基区渡越时间以提高频 率性能,应该如何全面考虑. 相似文献
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钛扩散LiNbO3单模波导场分布 总被引:1,自引:1,他引:0
给出了 Ti 扩散 LiNbO3条波导任意阶导模场分布的近似解,通过逐点近似法确定待定常数,分析了它的物理意义,也给出了导模的传播常数和有效折射率的解析式,与变分法相比,这种方法物理概念明确,计算量小,寻优简单,为集成光学的设计提供了一种计算精度较高的计算方法. 相似文献
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近贴聚焦开口式微通道板象增强器调制传递函数的近似计算 总被引:1,自引:1,他引:0
提出了根据微通道板输出电子轴向能量分布的测量原理,近似计算由微通道板和荧光屏组成的近贴聚焦开口式象增强器调制传递函数(MTF)的数值方法。讨论了近似方法带来的计算误差及提高计算准确性的可能途径。 相似文献
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宋建民 《原子与分子物理学报》2012,29(6)
在密度泛函理论(DFT)框架下, 应用改进的基本度量理论(MFMT)表达硬球作用对自由能泛函的贡献, 根据统计力学理论结合加权密度近似(WDA)表达偶极作用对自由能泛函的贡献,得到了方势阱偶极流体在平行板间的密度分布表达式, 计算了偶极流体在两平行板间的密度分布, 并探讨了方势阱深度和宽度对体系密度分布的影响. 此外, 通过体系密度分布, 进一步分析了方势阱宽度和深度以及板间尺度与溶剂化力的关系. 相似文献
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在密度泛函理论(DFT)框架下, 应用改进的基本度量理论(MFMT)表达硬球作用对自由能泛函的贡献, 根据统计力学理论结合加权密度近似(WDA)表达偶极作用对自由能泛函的贡献,得到了方势阱偶极流体在平行板间的密度分布表达式, 计算了偶极流体在两平行板间的密度分布, 并探讨了方势阱深度和宽度对体系密度分布的影响. 此外, 通过体系密度分布, 进一步分析了方势阱宽度和深度以及板间尺度与溶剂化力的关系. 相似文献
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光谱仪谱线和谱带弯曲现象的精确表述方式 总被引:1,自引:0,他引:1
巴音贺希格 《光谱学与光谱分析》2005,25(9):1524-1529
在矢量衍射理论基础上给出了任意倾斜入射下的光栅方程一般形式以及衍射极角和衍射方位角的完整解析表达式,由此首次导出了平面光栅光谱仪谱线和谱带弯曲量的精确计算公式和对应于衍射极角和衍射方位角的两类角色散公式,比较了谱线弯曲精确公式和近似公式的计算结果,进而指出和弥补了近似公式的不足,并数值考察了入射狭缝高度对光谱仪色散能力的影响程度。由于在以上各式的推导过程中未作任何近似,且涉及到了导致谱线和谱带弯曲的所有可能因素,因而它要比以往所用近似公式更为全面和可靠,可作为实际光谱仪器设计、测试、装调和使用的理论依据。 相似文献
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考虑具有强度耦合的广义Jaynes-Cummings模型与压缩真空相互作用。根据Pegg和Bamett新的相位理论,不仅得到了压缩真空场的相位分布,相位期待值和相位涨落的普遍表示式,及其演化图示,而且还导出了弱压缩真空和强压缩真空情形的近似角极表示式。对于压缩真空的压缩量与相位特性之间的关系进行了简要讨论。 相似文献
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平面波经小圆孔非傍轴衍射的轴上光强解析分析 总被引:3,自引:2,他引:1
用亥姆霍兹 基尔霍夫积分定理和基尔霍夫边界条件,推导出了平面波经小圆孔非傍轴衍射时轴上强度的简单解析表达式,研究了平面波经小圆孔后整个衍射空间非傍轴的轴上光强分布.给出了计算圆孔菲涅尔数的精确公式,重新检查了通常的菲涅尔数公式的有效性.数值计算显示,应用解析表达式所得的结果与应用衍射积分公式所得的结果完全一致. 相似文献
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As is well known in statistical physics, the stationary distribution can be obtained by maximizing entropy. We show how one can reconstruct the formula for entropy knowing the formula for the stationary distribution. A general case is discussed and some concrete physical examples are considered. 相似文献
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Yury M. Zinoviev 《Communications in Mathematical Physics》1995,174(1):1-27
A new inversion formula for the Laplace transformation of tempered distributions with supports in the closed positive semiaxis is obtained. The inverse Laplace transform of a tempered distribution is defined by means of a limit of a special distribution constructed from this distribution. The weak spectral condition on the Euclidean Green's functions implies that some of the limits needed for the inversion formula exist for any Euclidean Green's function with an even number of variables. We then prove that the initial Osterwalder-Schrader axioms [1] and the weak spectral condition are equivalent with the Wightman axioms.The research described in this publication was made possible in part by Grant No. 93-011-147 from the Russian Foundation for Basic Research 相似文献
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A simple phenomenological formula for the gluon distribution function in a proton is proposed. The reported results of calculations of the cross section of Higgs boson production via gluon fusion with higher-order QCD radiative corrections are reproduced using this formula and the one-loop amplitude. 相似文献
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A.V. Volotka V.M. Shabaev G. Plunien G. Soff 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,23(1):51-56
The finite nuclear size effect on the hyperfine splitting of low-Z hydrogen-like atoms is studied in the external field approximation. A simple non-relativistic formula is proposed which expresses
the nuclear size correction to the hyperfine splitting in terms of moments of the nuclear charge and magnetization distribution.
The numerical results obtained via this formula are compared with corresponding results derived by means of the Zemach formula. A relativistic formula for the
nuclear size correction to the hyperfine splitting is also derived.
Received 18 March 2002 / Received in final form 14 November 2002 Published online 28 January 2003
RID="a"
ID="a"e-mail: plunien@physik.tu-dresden.de 相似文献
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B. A. Zon 《Journal of Experimental and Theoretical Physics》2000,91(5):899-904
A general formula is obtained for the probability of tunneling ionization of an atom accompanied by excitation of the core. This formula is a generalization of the Carlson formula for the probability of a single-photon two-electron transition in atoms. The limiting case of this formula, just as that of the Carlson formula, is the well-known random-perturbations approximation. Numerical results are presented for Zn, Sr, and Cd atoms. For these atoms the contribution of the excited states of singly charged ions to the probability of the formation of doubly charged ions is a nonmonotonic function of the laser radiation intensity. Analysis of the tunneling ionization of molecules shows that with overwhelming probability an ion is formed in the ground vibrational state, while for the standard photoionization the distribution over vibrational states is determined by the Franck-Condon factors. 相似文献
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StudyOnLaserFiberDiameterMeasurementInstrument¥ZHOUGe;LIUZeyi;LIHeqiao;MAOYi;ZHANGYimo(InstituteofOptoelectronic&PrecisionEng... 相似文献
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Kisei Kinoshita 《Fortschritte der Physik》1976,24(6):341-355
Single-particle distributions in the entire Peyrou plot at CERN-PS ∼ ISR energies are unifiedly described by the whole-region formula, which incorporates both parton model results at large pT and all of the Mueller-Regge forms at small pT. The quantum number dependence of the distributions is explained by the formula as due to the intimate relation between the energy-momentum flow and the quantum-number flow carried by valence urbaryons. A field theoretical basis of the formula is provided by a covariant model of the hadron-urbaryon amplitude which is parametrized in terms of valence urbaryon lines and pair effects. Two-body reactions at all angles are also described by the formula as the exclusive limit of inclusive reactions. The construction of a formula for inclusive two-particle distribution is briefly discussed. 相似文献
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激光衍射粒度分析仪粒度分布求解方法的研究 总被引:8,自引:3,他引:5
本文介绍了激光衍射粒度分析仪的基本原理,给出了光电探测器上的光能分布公式,对其求解方法进行了详细分析,提出了利用改进的最小二乘法求解粒度分布的新方法.最后分别利用函数限制解法和自由分布解法对两种情况的粒度分布进行了数值模拟计算. 相似文献