首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   42篇
  免费   5篇
  国内免费   1篇
化学   23篇
力学   6篇
数学   6篇
物理学   13篇
  2023年   1篇
  2022年   3篇
  2019年   3篇
  2018年   1篇
  2017年   1篇
  2016年   2篇
  2015年   2篇
  2013年   1篇
  2012年   5篇
  2011年   1篇
  2010年   2篇
  2009年   1篇
  2008年   6篇
  2007年   1篇
  2006年   4篇
  2004年   5篇
  2003年   4篇
  2002年   1篇
  2000年   2篇
  1995年   1篇
  1983年   1篇
排序方式: 共有48条查询结果,搜索用时 15 毫秒
31.
A secret sharing system can be damaged when the dealer cheating occurs. In this paper,two kinds of secret sharing schemes based on linear code are proposed. One is a verifiable scheme which each participant can verify his own share from dealer‘s distribution and ensure each participant to receive valid share. Another does not have a trusted center, here, each participant plays a dual-role as the dealer and shadow(or share) provider in the whole scheme.  相似文献   
32.
An improved procedure for the preparation of chiral NAD(P)H model, (SS)-1-benzyl-3-(p-tolylsulfinyl)-1,4-dihydropyridine, with satisfactary chemical yield and excellent enantiopurity is reported.  相似文献   
33.
The uniaxial and non-proportionally multiaxial ratcheting behaviors of SS304 stainless steel at room temperature were initially researched by experiment and then were theoretically described by a cyclic constitutive model in the framework of unified visco-plasticity. The effects of cyclic stress amplitude, mean stress, and their histories on the ratcheting were experimentally investigated under uniaxial and different multiaxial loading paths. The shapes of non-proportional loading paths were linear, circular, elliptical and rhombic, respectively. In the constitutive model, the rate-dependent behavior of the material was reflected by a viscous term; the cyclic flow and cyclic hardening behaviors of the material under asymmetrical stress-controlled cycling were reflected by the evolution rules of kinematic hardening back stress and isotropic deforming resistance, respectively. The effect of loading history on the ratcheting was also considered by introducing two fading memorization functions for maximum inelastic strain amplitude and isotropic deformation resistance, respectively, into the constitutive model. The effect of multiaxial loading path on the ratcheting was reflected by a non-proportional factor defined in this work. The predicting ability of the developed model was proved to be good by comparing the simulations with corresponding experiments.  相似文献   
34.
二碘化钐作为预催化剂的有机反应   总被引:2,自引:0,他引:2  
徐凡  朱雪华  沈琪 《有机化学》2004,24(8):872-881
二碘化钐是二价稀土试剂中的代表化合物,在有机合成中用途广泛.综述了近年来催化量二碘化钐促进的有机反应,介绍了二碘化钐作为预催化剂在催化有机反应方面所体现的反应活性及选择性.  相似文献   
35.
Copolymer, poly(acrylonitrile-co-methyl methacrylate) (P(AN-co-MMA)), was synthesized by solution polymerization with different mole ratios of monomers, acrylonitrile (AN) and methyl methacrylate (MMA). Polyethylene (PE) supported copolymer and gel polymer electrolyte (GPE) were prepared with this copolymer and their performances were characterized with FTIR, TGA, SEM, and electrochemical methods. It is found that the GPE using the PE-supported copolymer with AN to MMA = 4:1 (mole) exhibits an ionic conductivity of 2.06 × 10−3 S cm−1 at room temperature. The copolymer is stable up to 270 °C. The PE-supported copolymer shows a cross-linked porous structure and has 150 wt% of electrolyte uptake. The GPE is compatible with anode and cathode of lithium ion battery at high voltage and its electrochemical window is 5.5 V (vs. Li/Li+). With the application of the PE-supported GPE in lithium ion battery, the battery shows its good rate and initial discharge capacity and cyclic stability.  相似文献   
36.
Calcium plays an important role in barrier function repair and skin homeostasis. In particular, calcium phosphates (CaPs) are well established materials for biomedical engineering due to their biocompatibility. To generate biomaterials with a more complete set of biological properties, previously discarded silk sericin (SS) has been recovered and used as a template to grow CaPs. Crucial characteristics for skin applications, such as antibacterial activity, can be further enhanced by doping CaPs with cerium (Ce) ions. The effectiveness of cell attachment and growth on the materials highly depends on their morphology, particle size distribution, and chemical composition. These characteristics can be tailored through the application of oscillatory flow technology, which provides precise mixing control of the reaction medium. Thus, in the present work, CaP/SS and CaP/SS/Ce particles were fabricated for the first time using a modular oscillatory flow plate reactor (MOFPR) in a continuous mode. Furthermore, the biological behavior of both these composites and of previously produced pure CaPs was assessed using human dermal fibroblasts (HDFs). It was demonstrated that both CaP based with plate-shaped nanoparticles and CaP-SS-based composites significantly improved cell viability and proliferation over time. The results obtained represent a first step towards the reinvention of CaPs for skin engineering.  相似文献   
37.
泡沫材料的应变率效应   总被引:26,自引:6,他引:26  
对泡沫材料的应变率敏感性进行了系统深入的讨论,认定这种材料是应变率敏感材料,这种敏感性主要是由于泡孔的变形特性产生的。泡沫材料变形的局部化、微观惯性和致密性导致压垮应力明显提高,基体的应变率效应及泡孔的形状大小并不能对泡沫材料应变率敏感性起主导作用。  相似文献   
38.
39.
The uniaxial ratcheting of SS304 stainless steel at high temperatures (300, 600 and 700 °C) were analyzed experimentally, and described by a cyclic constitutive visco-plasticity model. The rate dependence of the material was accounted for by introducing a viscous term. The cyclic hardening and cyclic flow behavior of the material under asymmetrical stress-controlled cycling were described by the evolution rules of kinematic hardening back stress and isotropic deforming resistance. Under the isothermal condition, temperature effect was included by terms involving temperature in the evolution equations of isotropic deforming resistance. The effect of load history on ratcheting was also considered by introducing a fading memory function of the maximum inelastic strain amplitude and isotropic deformation resistance. After the material constants were determined from the experimental data, the uniaxial ratcheting of SS304 stainless steel was numerically simulated and compared with the corresponding experimental results at high temperatures. The predicted results agree well with the experimental ones.  相似文献   
40.
晶体材料中3d2态离子自旋哈密顿参量的微观起源   总被引:11,自引:0,他引:11       下载免费PDF全文
杨子元 《物理学报》2004,53(6):1981-1988
采用了中间场耦合图像,考虑了以前研究中被忽略的SS (spin-spin)磁相互作用以及SOO (spin-other-orbit)磁相互作用,利用完全对角化方法,研究了3d2态离子在三角对称 (C3v, D3, D3d)晶体中自旋哈密顿(SH)参量的微观起源.发现自旋哈密顿参量 (包括零场分裂参量D和g因子g∥,g⊥)来自四种耦合机理:(1)SO (spin-orbit)耦合机理; (2) SS耦合机理;(3)SOO 关键词: 自旋哈密顿参量 2态离子')" href="#">3d2态离子 三角对称晶场 SS与SOO作用 SO-SS-SOO联合作用机理  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号