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991.
R. S. Rivlin M. F. Beatty 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2003,54(6):954-963
A unit cube of compressible isotropic elastic material
undergoes a homogeneous dilatation by dead loading forces applied
to its faces. Conditions are obtained for stability of the
resulting equilibrium state. The physical nature of these
conditions is described and the results are illustrated for a
compressible Blatz-Ko foamed rubber material. 相似文献
992.
993.
V. Šepelák I. Bergmann A. Feldhoff P. Heitjans F. J. Litterst K. D. Becker 《Hyperfine Interactions》2005,165(1-4):81-87
The single-step synthesis of nanosized MgFe2O4 and NiFe2O4 via mechanochemical processing of binary oxide precursors is followed by 57Fe Mössbauer spectroscopy. Quantitative information is provided on both ionic and spin configurations in mechanosynthesized spinels. The response of the mechanosynthesized ferrite nanoparticles to changes in temperature is also studied. 相似文献
994.
SHAO Li ZHANG Quanxing LUO Gang CHEN Jinlong State Key Laboratory of Pollution Control Resources Reuse Department of Environmental Engineering Nanjing University Nanjing China 《Chinese Journal of Reactive Polymers》2002,(2)
1. INTRODUCTION The chemical name of sorbic acid is 2,4-hexadienoic acid. Toxicity of sorbic acid is less than any other preservative, which is internationally acknowledged. Sorbic acid can participate in mans metabolism and can be easily oxidized, then … 相似文献
995.
L. I. Valuev G. A. Sytov I. L. Valuev M. V. Ul’yanova L. V. Vanchugova N. A. Plate 《Russian Chemical Bulletin》2004,53(11):2611-2616
Polymeric systems for targeting polypeptide medicinal drugs onto the wall of the small intestine after oral administration were synthesized. These systems are composed of particles of ovomucoid-modified polyacrylamide hydrogel with insulin physically immobilized in its bulk. In vitro experiments have demonstrated the enhanced stability of the immobilized polypeptide against proteolysis and the affinity of polymeric particles to lectin-containing surfaces. The efficiency of the systems obtained was demonstrated in experiments with animals and diabetes patients. The effrct of these systems upon oral administration was qualitatevely similar to that of subcutaneously administered native insulin.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2504–2509, November, 2004. 相似文献
996.
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
997.
998.
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
999.
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
1000.
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