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991.
非相干光作用下的Ce:BaTiO3自泵浦相位共轭镜特性 总被引:1,自引:0,他引:1
地Ce:BaTiO3晶体的自泵浦相位共竟然非相干光作用下自泵浦相位共轭反射率增强的特性进行了研究。实验是在He-Ne激光产生稳态自泵浦相位共轭输出后,用非相干光平行c轴照射来获得这一增强特性的,当水平移动非相干光入射位置,发现有两个区域非相干光作用能使相位共轭反射率增加,本文对此进行了相应的分析和讨论。 相似文献
992.
The shear compression specimen (SCS), which is used for large strain testing, is thoroughly investigated numerically using
three-dimensional elastoplastic finite element simulations. In this first part of the study we address quasi-static loading.
A bi-linear material model is assumed. We investigate the effect of geometrical parameters, such as gage height and root radius,
on the stress and strain distribution and concentration. The analyses show that the stresses and strains are reasonably uniform
on a typical gage mid-section, and their average values reflect accurately the prescribed material model. We derive accurate
correlations between the averaged von Mises stress and strain and the applied experimental load and displacement. These relations
depend on the specimen geometry and the material properties. Numerical results are compared to experimental data, and an excellent
agreement is observed. This study confirms the potential of the SCS for large strain testing of material. 相似文献
993.
994.
Parham Sadooghi 《Journal of Quantitative Spectroscopy & Radiative Transfer》2005,93(4):461-472
An analytic solution is presented for describing combined radiation and conduction heat transfer in a spherical fiber thermal protection exposed to combined radiative and convective heating. The solution includes the equation of radiative transfer within the material, coupled to a transient energy equation that contains both radiative and convective terms. At elevated temperatures radiative transfer becomes important, and if several hot surfaces view each other, the radiation exchange process must be considered carefully. Some thermal protections are partially transparent to thermal radiation. Hence, an exchange process is complicated by radiation penetrating into and coming out of material. The radiation leaving an area depends on the temperature distribution inside that area and that is unknown and is affected by the exchange process to other areas. The analysis has allowed for unlimited spectral detail but assumes that the various material properties do not vary significantly with temperature. Transient temperature distributions are obtained for the boundary conditions of external radiation and convection. The present analysis includes the influence of reflectivity, surface radiative properties and spectral properties on the temperature distributions. 相似文献
995.
We consider a question related to the kinetic theory of granular materials. The model of hard spheres with inelastic collisions is replaced by a Maxwell model, characterized by a collision frequency independent of the relative speed of colliding particles. Our main result is that, in the space-homogeneous case, a self-similar asymptotics holds, as conjectured by Ernst–Brito. The proof holds for any initial distribution function with a finite moment of some order greater than two. 相似文献
996.
采用Nd0 .7Sr0 .3MnO3/SrTiO3/YBa2 Cu3O7-δ的异质结构 ,研究了自旋极化准粒子的注入效应 .在 5 6 μm宽的YBCO膜条上成功地制备了与超导膜条同样宽度但不同长度的六个注入结区 ,长度L分别为 80 μm ,4 0 μm ,2 0 μm ,10 μm ,5 μm和 2 μm .80nm厚的YBCO薄膜在 16K温度下Jc 为 2× 10 5A/cm2 .Iin=0 .5mA的自旋电流注入下 ,随L从 80 μm逐渐顺次减小时 ,注入效率 η =ΔJc/ΔJin逐渐增大 .而当L≤ 2 0 μm后 ,η不再增加 ,达到几乎相同的值 (~ 6 ) .初步分析认为这与自旋极化准粒子在超导膜内的有效自旋扩散长度有关 .异质结构中YBCO薄膜的超导电性以及注入窗口的尺寸对获得大的自旋注入效率十分重要 . 相似文献
997.
Two new blue luminescent zinc and beryllium complexes with Schiff base calixarene derivative as the ligand were prepared.Their luminescent properties were determined,which indicated that they had strong blue fluorescent properties.They also had good solubility and film formation.These new complexes can be used as blue organic electroluminescent materials (OELMs) in organic electroluminescent devices. 相似文献
998.
区间数的标准表示及其四则运算法则与泛灰数的内在联系 总被引:2,自引:0,他引:2
在回顾泛灰数四则运算法则基础上,给出了区间数的标准表示,论述了标准区间数的四则运算法则与泛灰数的内在联系及其应用前景. 相似文献
999.
Neslihan Saki Engin U. Akkaya 《Journal of inclusion phenomena and macrocyclic chemistry》2005,53(3):269-273
A novel dimeric calixpyrrole has been synthesized. The dimer forms stable complexes with p-nitrophenolate ion with a concomitant reduction in extinction coefficient. The chromogenic anion is displaced by the addition of various anions like fluoride and acetate. Effective optical sensing of these anions is accomplished using the calixpyrrole dimer. 相似文献
1000.