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71.
The Penning surface plasma source is adopted as the China Spallation Neutron Source (CSNS) H- ion source. The designed energy and beam current of the source are 50 keV and 20 mA, respectively, with a normalized root mean square (norm. rms.) emittance of 0.2 πmm·mrad. The construction of a H- ion source test stand has been completed, and the commissioning of the source is in progress. Stable H- ion beams with energy of 50 keV and current up to 50 mA are attained. Emittance measurement for the H- beam is being prepared. 相似文献
72.
美式看跌期权定价中的小波方法 总被引:3,自引:0,他引:3
本文采用有限差分格式和 Daubechies正交小波 ,提出了一种求解 Black- Scholes方程数值解新算法 .为美式看跌期定价提供了一条新的途径 .利用小波基的自适应性和消失矩特性 ,使偏微分算子矩阵和小波级数稀疏化 ,大大减少了计算量 . 相似文献
73.
用逐次残余法分析了聚乙烯和聚苯忆乙烯缓冲材料的应力松也试验数据,结果表明可用有限个并联的Maxwell模型来表示这两种材料的应务松驰试验曲线。 相似文献
74.
75.
First-Principles Calculations of Elastic Properties of LaNi4.75Sn0.25 Alloys under Pressure 下载免费PDF全文
The equilibrium lattice constants, bulk modulus, shear modulus, elastic constants and Debye temperature of LaNi4.75 Sn0.25 under pressure are calculated using the full-potential linearized augmented plane wave (FP-LAPW) method as well as the quasi-harmonic Debye model. The results at zero pressure are in excellent agreement with the experimental data. The Sn atom is found to occupy the equivalent 3g site (0.5a, 0.75b, 0.5c) in the quadruple cell. The Debye temperature of LaNi4.75Sn0.25 is lower than that of LaNi5. The dependences of bulk modulus on finite temperature and on finite pressure are also investigated. The results show that the bulk modulus B increases monotonously as pressure increases. 相似文献
76.
The equilibrium lattice constants, temperature dependence of bulk modulus, the pressure dependence of the normalized volume V/V0, elastic constants Cij and bulk modulus of LaNi5 crystal are obtained using the firstprincipies piane-wave pseudopotential method in the GGA-PBE generalized gradient approximation as well as the quasi-harmonic Debye model. We analyse the relationship between bulk modulus and temperature up to 2000 K and obtain the relationship between bulk modulus B and pressure at diFFerent temperatures. It is found that the bulk modulus B increases monotonously with increasing pressure. Moreover, the pressure dependences of Debye temperatures and the pressure derivatives of lattice constants are also successfully obtained. The calculated results are in agreement with the experimental data and the other theoretical results. 相似文献
77.
Theoretical Study of Compressibility and Thermoelasticity of LaNi5-xAlx (x= 0.3, 0.5 and 1.0) 下载免费PDF全文
The compressibility, the temperature dependence of bulk modulus, the pressure dependence of normalized volume V/V0, thermal expansion coefficient and Debye temperature of LaNi5-xAlx compounds are successfully obtained using the first-principles plane-wave pseudopotential (PW-PP) method, the EOSFIT6.0 software and the quasiharmonic Debye model. The rapid decrease of relative lattice constant a/a0 shows that the deformation is easier in directions normal to the c-axis than that along it. The relationships between bulk modulus B and pressure at different temperatures are also analysed. It is found that the bulk modulus B increases monotonically with increasing pressure. Moreover, the pressure dependences of thermal expansion and Debye temperature are also successfully obtained. The calculated results are in agreement with the experimental data. 相似文献
78.
Dependence of bulk modulus on both pressure and temperature, the elastic constants Cij and the pressure and temperature dependence of normalized volume V/Vo of cubic Ni2MnGa alloy are successfully obtained using the first-principles plane-wave pseudopotential (PW-PP) method as well as the quasi-harmonic Debye model. We analyse the relationship between bulk modulus and temperature up to 800 K and obtain the relationships between bulk modulus B and pressures at different temperatures. It is found that the bulk modulus B increases monotonically with increasing pressure. Moreover, the temperature dependences of the Debye temperature are also analysed. The calculated results are in agreement with the available experimental data and the previous theoreticM results. 相似文献
79.
本文发现了一种新的反应.吡啶氯化铜络合物(Py2CuCl2)在乙醚中与金属钠作用后,能为卤代烷烃所烃化,反应后将络合物加碱分解,可得到γ-烷基吡啶(主产物)和α-烷基吡啶. 相似文献
80.