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Monte Carlo simulation of the dynamic evolution ofbinary lamellar eutectic in directional solidification 总被引:1,自引:0,他引:1 下载免费PDF全文
The dynamic evolution of the lamellar eutectic of binary alloys in directional solidification is studied in detail using the Monte Carlo technique. The simulated results can be summarized into two aspects: ({1}) the lamellar spacing λ is found to be inversely proportional to the chemical potential difference Δμ, predicting a linear relationship between the kinetic supercooling ΔT_k and total supercooling at the solid/liquid (S/L) interface; (2) as the solidifying velocity R is low, the dynamic product λ^{2}R shows a considerable dependence on temperature gradient G_T in the liquid in front of the S/L interface, although this dependence becomes much weaker at a high R. 相似文献
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关于麦克斯韦方程组的讨论 总被引:5,自引:0,他引:5
本文讨论了麦克斯韦方程组的来龙去脉、形式和地位,对麦克斯韦主程组的教学具有一定的参考价值。 相似文献
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Squeezing-Displacement Dynamics for One-Dimensional Potential Well with Two Mobile Walls where Wavefunctions Vanish 下载免费PDF全文
We show that the dynamics/or a particle confined in a one-dimensional potential well with two mobile boundaries where wavefunctions vanish can be converted to the case as if the boundary was time-independent at the expense of an appropriate time-dependent Hamiltonian. The squeezing-displacement operator can be derived, and the corresponding Flamiltonian is determined by the situation of mobile boundaries. 相似文献
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使用基于密度泛函理论的CASTEP软件计算了BAM:Eu2+(BaMgAl10O17:Eu2+)荧光粉在SiN掺杂前后的能带、态密度、吸收光谱和Mulliken布居.Eu2+处于BR位置光吸收更强;SiN掺杂使处于BR位置的Eu2+的数量上升,而处于mO位置的Eu2+的数量下降,抵消了SiN掺杂降低Eu的态密度对光谱的影响.所以适量掺杂的SiN提高了BAM:Eu2+荧光粉的吸收发射光谱强度.Si-N键和Eu-N键的Mulliken布居数分别高于Al-O键和Eu-O键, 说明Si-N键和Eu-N键的共价性分别强于Al-O键和Eu-O键.发光中心Eu2+局域结构共价性的增强降低了BAM:Eu2+镜面层的活性,这是SiN掺杂提高BAM:Eu2++荧光粉光学稳定性的主要原因. 相似文献
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We study the long-time limit behavior of the solution to an atom’s master equation.For the first time we derive that the probability of the atom being in the α-th(α = j + 1-j z,j is the angular momentum quantum number,j z is the z-component of angular momentum) state is {(1- K/G)/[1-(K/G) 2j+1 ]}(K/G) α-1 as t → +∞,which coincides with the fact that when K/G > 1,the larger the α is,the larger the probability of the atom being in the α-th state(the lower excited state) is.We also consider the case for some possible generalizations of the atomic master equation. 相似文献
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We explore the theoretical possibility of extending the usual squeezed state to those produced by nonlinear singlemode squeezing operators. We derive the wave functions of exp[-(ig/2)((1-X2)1/2P + P(1-X2)1/2)]|0 in the coordinate representation. A new operator’s disentangling formula is derived as a by-product. 相似文献
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α-SiAlON是一种典型的新型硅氮氧荧光体基底材料。通过高温固相反应法合成了化学式为M0.75Eu0.05Si9.6Al2.4O0.8N15.2(M=Ca,Mg)的黄色氮氧化物荧光粉Ca-α-SiAlON:Eu2+和Mg-α-SiAlON:Eu2+。通过光致发光谱图发现,Ca0.75Eu0.05Si9.6Al2.4O0.8N15.2的发光强度比Mg0.75Eu0.05Si9.6Al2.4O0.8N15.2高得多。然后使用基于密度泛函理论的CASTEP程序,计算了两种荧光粉的能带结构和态密度。通过对态密度的分析,发现Ca的分波态密度对总态密度的贡献比Mg的大,这是因为Ca的3d能级和Eu的5d能级更接近,两者充分混合,增大了Eu的5d能带的态密度,从而解释了Ca-α-SiAlON:Eu2+的光学性能好于Mg-α-SiAlON:Eu2+的本质原因。 相似文献