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101.
The pressure dependence of the direct and indirect bandgap of epitaxial In0.52Al0.48As on InP(001) substrate has been measured using photoluminescence up to 92 kbar hydrostatic pressure. The bandgap changes
from Γ toX at an applied pressure of ∼ 43 kbar. Hydrostatic deformation potentials for both the Γ andX bandgaps are deduced, after correcting for the elastic constant (bulk modulus) mismatch between the epilayer and the substrate.
For the epilayer we obtain
and+(2.81±0.15)eV for the Γ andX bandgaps respectively. From the pressure dependence of the normalized Γ-bandgap photoluminescence intensity a Γ-X lifetime ratio, (τΓ/τ
X
), of 4.1×10−3 is deduced. 相似文献
102.
Experiments with heavy ions at moderate energies show the importance of deformation in heavy ion collisions. A deformation
model which takes deformation dynamically into account is developed. Having described fusion and deep inelastic collision
for a very heavy system (Xe + Bi) and a medium heavy system (Ar + Th) at various energies successfully, we turn to some comparatively
lighter heavy ions where fusion is the most dominant feature. Fusion cross-sections for six pairs of lighter systems (35Cl +116Sn,58Ni+62Ni,35Cl+62Ni,32S+24Mg,24Mg+24Mg and12C+27Al) have been obtained using our deformation model which agree well with experiment. The two-slope-behaviour of fusion excitation
function which is an important feature of light ion fusion systematics is also obtained, in our model calculations for all
the systems studied. 相似文献
103.
104.
David Bleecker 《Geometriae Dedicata》1997,64(2):193-227
In 1955 N. Kuiper and J. Nash proved that given a C
embeddingF of a C
Riemannian n -manifold (M,g) in E
n+1 which is short in the sense that the metric induced by F is less thang, there is a C
1 isometric embedding which is arbitrarily C
0-close to F. We extend the Nash--Kuiper result for compact M to the case of deformations. In other words, we prove that given a continuous family of short C
embeddings
(
) of a compact Riemannian n-manifold M , there is an isometric deformation through C
1 embeddings which is C
0 -close to F. With more assumptions which are typically met in practice, this result is shown to hold in the more difficult case where F(s) is short for s>0 andF(0) is isometric. We use this to prove that if a C
convex hypersurface is sufficiently close to being planar in an average sense (e.g. an oblate spheroid in E
3 with axis ratio more than
, then it admits an isometric deformation which increases the enclosed volume. 相似文献
105.
Givenμ, κ, c>0, we consider the functional
defined on allR
n
-valued functionsu on the open subset Ω ofR
n
which are smooth outside a free discontinuity setS
u, on which the tracesu
+,u
− on both sides have equal normal component (i.e.,u has a tangential jump alongS
u).E
Du=Eu − 1/3 (divu)I, withEu denoting the linearized strain tensor.
The functionalF is obtained from the usual strain energy of linearized elasticity by addition of a term (the second integral) which penalizes
the jump discontin uities of the displacement.
The lower semicontinuous envelope
is studied, with respect to theL
1 (Ω;R
n
)-topology, on the spaceP(Ω) of the functions of bounded deformation with distributional divergence inL
2(Ω) (F is extended with value +∞ on the wholeP(Ω)). The following integral representation is proved:
whereϕ is a convex function with linear growth at infinity. NowEu is a measure,ɛ
Du represents the density of the absolutely continuous part of the absolutely continuous part ofE
Du, whileE
s
D
u denotes the singular part and ϕ∞ the recession function ofϕ.
Finally, we show that
coincides with the functional which intervenes in the minimum problem for the displacement in the theory of Hencky’s plasticity
with Tresca’s yield conditions. 相似文献
106.
本文基于Reddy高阶剪切变形板理论导出Karman型非线性大挠度方程并用于层合板热后屈曲分析.分析中计及板初始几何缺陷和热效应.给出了四边简支.对称正交铺设层合板在均匀或非均匀抛物型热分布作用下的后屈曲分析.采用摄动-Galerkin混合法确定板的热屈曲载荷与热后屈曲平衡路径.同时讨论了横向剪切变形,板长宽比,铺层数以及初始几何缺陷等各种参数变化的影响. 相似文献
107.
径向基函数插值方法在动网格技术中的应用 总被引:3,自引:0,他引:3
分析用于非结构网格的弹簧比拟和用于结构网格的无限插值动态网格方法在实际应用中的优缺点,提出无需网格连接关系的基于径向基函数(radial basis functions,RBF)插值的动网格技术并编制相应的网格运动计算程序.以二维菱形翼的旋转运动及三维菱形翼的柔性变形为例,分析不同基函数和紧支半径的选取对网格质量及计算效率的影响,并通过与弹簧比拟方法的对比验证了RBF方法的有效性.结果表明:RBF方法数据结构简单,计算效率高,适应大变形能力强,可以有效地实现计算流体力学中的网格运动问题. 相似文献
108.
在准静态条件和旋转流体场中采用乳液微封装技术制备约2 mm的大直径W1/O/W2乳粒,研究了有机相浓度和水溶性聚合物浓度对W1/O/W2乳粒稳定性的影响。从乳粒受力和变形的角度,探索了旋转流体场对W1/O/W2乳粒动力学稳定性的增强作用机制。研究表明:无论是在准静态条件下还是旋转流场中,乳粒稳定性都随聚苯乙烯浓度单一上升,随聚乙烯醇浓度呈现先上升后下降的趋势;相对于准静态条件,旋转流体场在一定条件下对大直径W1/O/W2乳粒的动力学稳定具有明显增强作用。 相似文献
109.
利用强流脉冲电子束装置在各种工艺条件下对奥氏体不锈钢、单晶铝及多晶铝等面心立方金属进行辐照处理.利用扫描电子显微镜和透射电子显微镜等详细分析了辐照样品的变形组织与结构.通过分析,在一定程度上建立起强流脉冲电子束诱发的应力特征与变形结构之间的关系,并对目前现有的几种应力波数值模拟结果进行了分析.实验结果表明,强流脉冲电子束能够在材料内部诱发102—103MPa的应力,其传播方式与材料的 晶体结构关系密切.这一应力是导致材料深层性能与微观组织结构发生变化的根源所在.
关键词:
强流脉冲电子束
应力
微观结构
变形 相似文献
110.
Peter Li Luen-fai Tam DaGang Yang 《Transactions of the American Mathematical Society》1998,350(3):1045-1078
We study the elliptic equation on complete noncompact Riemannian manifolds with nonnegative. Three fundamental theorems for this equation are proved in this paper. Complete analyses of this equation on the Euclidean space and the hyperbolic space are carried out when is a constant. Its application to the problem of conformal deformation of nonpositive scalar curvature will be done in the second part of this paper.