共查询到20条相似文献,搜索用时 203 毫秒
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将粒子输运的蒙特卡罗方法与器件数值模拟的有限体积法相耦合来模拟典型金属氧化物半导体场效应管(MOSFET)的长期辐射效应。二氧化硅中的陷阱电荷及硅中的自由电子和空穴均使用漂移扩散模型来描述,入射粒子的能量沉积可作为源项耦合至漂移扩散模型方程,并根据有限体积法得到控制方程的离散格式,方程的数值解即为MOSFET的长期辐射响应结果。使用该方法模拟了MOSFET受射线粒子辐照后的阈值电压漂移与关态漏电流现象。结果表明,耦合方法适用于典型半导体器件长期辐射效应模拟,其阈值电压漂移及漏电流计算结果与文献符合较好。 相似文献
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粒子输运离散纵标方程基于界面修正的并行计算方法 总被引:1,自引:1,他引:0
为了改造粒子输运方程求解的隐式格式,研究设计适应大型并行计算机的并行计算方法,介绍一类求解粒子输运方程离散纵标方程组的基于界面修正的源迭代并行计算方法.应用空间区域分解,在子区域内界面处首先采用迎风显式差分格式进行预估,构造子区域的入射边界条件,然后,在各个子区域内部进行源迭代求解隐式离散纵标方程组.在源迭代过程中,在内界面入射边界处采用隐式格式进行界面修正.数值算例表明该并行计算方法在精度、并行度、简单性诸方面均具有良好的性质. 相似文献
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结合辐射输运方程,在流体力学方程组的能量方程中加入包括空气吸收的激光能量以及高温气体向周围辐射损失的能量源项,转化为辐射流体力学方程组,建立了用于模拟吸气式激光推进中能量沉积过程的物理力学模型和计算方法。该辐射流体力学计算程序可以很好地模拟激光能量沉积过程中空气对激光能量的吸收、等离子体对激光的屏蔽作用以及激光维持的爆轰波的传播规律,计算得到激光能量的沉积效率约为57%,激光维持的爆轰波的传播速度与同等条件下的理论和实验结果吻合得较好。 相似文献
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从Lagrange观点出发,采用分裂格式法求解一维辐射流体力学方程组中的三温方程,用于紧凑等离子体环与靶碰撞产生的X射线辐射的数值模拟研究。提出了求解电子、离子、辐射场三温相脱离的能量方程的隐式差分格式,介绍了能量交换项与压力做功及热传导项分开计算的分裂格式方法,数值模拟得到了其对温度变化的影响。 相似文献
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应用多光子非线性Compton散射模型和数值计算方法,研究了Compton散射对超强激光与等离子体作用中能量输运的影响,提出了将Compton散射光和入射超强光作为电子能量输运的新机制,给出了电子热传导新模型和能量输运数值计算结果。结果表明:散射使等离子体中Weibel不稳定性和自生磁场增强效应导致耦合光传输方向的电子密度显著减小,更多激光能量以热流形式分布在横向方向。散射使电子吸收能量的时间缩短和自生磁场线性阶段最大增长率增大效应导致等离子体表面处沿耦合激光横向方向的热流几乎被完全限制,电子在激光传输方向的能量显著增加。 相似文献
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Kovalev D Gross E Künzner N Koch F Timoshenko VY Fujii M 《Physical review letters》2002,89(13):137401
We demonstrate efficient resonant energy transfer from excitons confined in silicon nanocrystals to molecular oxygen (MO). Quenching of photoluminescence (PL) of silicon nanocrystals by MO physisorbed on their surface is found to be most efficient when the energy of excitons coincides with triplet-singlet splitting energy of oxygen molecules. The dependence of PL quenching efficiency on nanocrystal surface termination is consistent with short-range resonant electron exchange mechanism of energy transfer. A highly developed surface of silicon nanocrystal assemblies and a long radiative lifetime of excitons are favorable for achieving a high efficiency of this process. 相似文献
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X.L. Chen 《Journal of Quantitative Spectroscopy & Radiative Transfer》2003,77(3):233-271
A modified direct integration method is presented to solve three-dimensional radiative transfer in emitting, absorbing and linear-anisotropic scattering finite cylindrical media. This scheme effectively avoids an integral singularity in the coupled Fredholm type integral equations of radiative transfer. The scheme leads to faster and more accurate results, which are needed in combined mode and non-gray problems. The calculated incident radiation and heat fluxes agree well with published results by discrete ordinates method. Using the transformed integral equations, the effects of boundary emission and reflection can also be easily handled. 相似文献
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Rafif E. Hamam Aristeidis Karalis J.D. Joannopoulos Marin Solja?i? 《Annals of Physics》2009,324(8):1783-1795
Inspired by a quantum interference phenomenon known in the atomic physics community as electromagnetically induced transparency (EIT), we propose an efficient weakly radiative wireless energy transfer scheme between two identical classical resonant objects, strongly coupled to an intermediate classical resonant object of substantially different properties, but with the same resonance frequency. The transfer mechanism essentially makes use of the adiabatic evolution of an instantaneous (so called “dark”) eigenstate of the coupled 3-object system. Our analysis is based on temporal coupled mode theory (CMT), and is general enough to be valid for various possible sorts of coupling, including the resonant inductive coupling on which witricity-type wireless energy transfer is based. We show that in certain parameter regimes of interest, this scheme can be more efficient, and/or less radiative than other, more conventional approaches. A concrete example of wireless energy transfer between capacitively-loaded metallic loops is illustrated at the beginning, as a motivation for the more general case. We also explore the performance of the currently proposed EIT-like scheme, in terms of improving efficiency and reducing radiation, as the relevant parameters of the system are varied. 相似文献
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Jian-Feng Luo Sheng-Li Chang Xi Shen 《Journal of Quantitative Spectroscopy & Radiative Transfer》2008,109(15):2603-2612
The main objective of this paper is to extend to two-dimensional (2-D) medium the ray tracing-node analyzing method, which has already been successfully used to solve one-dimensional (1-D) problem of coupled heat transfer in a semitransparent medium. For simplicity, an infinitely long rectangular semitransparent medium with four black opaque surfaces is chosen as our studying object. A control volume method in the implicit scheme is adopted for discretizing the partial transient energy equation. In combination with spectral band model, the radiative heat source term is calculated using the radiative transfer coefficients (RTCs), which are deduced by the ray tracing method. The Partankar's linearization method is used to linearize the radiative source term and the opaque boundary condition, and the linearized equations are solved by the ADI method. Effects of absorption coefficient, refractive index and conductivity on transient cooling process in the 2-D gray rectangular medium are investigated under the condition that the radiation and convection processes cool one side of the rectangular medium while heat the remaining three sides. 相似文献
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L.H. Liu 《Journal of Quantitative Spectroscopy & Radiative Transfer》2002,74(1):97-114
A method is developed to analyze the transient coupled radiation-conduction in infinite semitransparent cylinders surrounded by isothermal black walls. The radiative heat source term is calculated by the radiative transfer coefficients and the transient energy equation is solved by an implicit finite difference method. The radiative transfer coefficients are deduced by use of the ray tracing method in combination with the Hottel and Sarofim zonal method. The effects of the related parameters on the transient radiative heat source and temperature distribution are analyzed. It is found that the peak of the dimensionless radial radiative heat source can be located at the interior shell of the cylinder with small optical thickness when heated by the surrounding irradiation. Treating the volume radiation as a surface radiation will result in large errors of transient temperature distribution for the cylinder with small optical thickness. 相似文献
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随着超短脉冲激光的快速发展,吸收散射性介质内的瞬态辐射传输引起了人们的广泛关注.本文基于离散坐标法和最小二乘有限元法(LSFEM),提出了模拟多维吸收散射性介质内瞬态辐射传输的数值模型.该模型有效地克服了在标准Galerkin有限元法(GFEM)中发生的伪振荡现象,在时间步长较大的情况下仍然可以得到光滑无振荡的解.而且,最小二乘法产生的求解系数矩阵是对称正定的,与GFEM中的系数矩阵相比,仅需要存储一半的非零系数,可以应用许多高效的迭代求解方法进行求解.为了检验模型,本文研究了一维吸收散射性介质内瞬态辐射传输问题,其结果与蒙特卡洛法(MCM)和积分模型法(IE)的结果进行了比较,结果证实:本文的方法可以精确、高效地模拟参与性介质内的瞬态辐射传输. 相似文献
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Based on the system of equations describing the populations of highly excited helium atomic levels and the electron density and energy balance and on the Maxwell equations, we develop a model for an electrodeless high-frequency discharge in helium. We suggest a method of self-consistent calculation in a plasma-field system. The model developed is used to calculate the radiative characteristics of high-frequency electrodeless lamps. The derived dependences of line intensities on gas pressure, lamp radius, and discharge power are in good agreement with the experimental data. 相似文献