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   24篇
  免费   3篇
化学   20篇
力学   2篇
数学   3篇
物理学   2篇
  2021年   1篇
  2020年   2篇
  2017年   2篇
  2015年   1篇
  2013年   2篇
  2012年   2篇
  2011年   4篇
  2010年   1篇
  2008年   2篇
  2007年   2篇
  2006年   1篇
  2005年   2篇
  2003年   2篇
  2002年   2篇
  1990年   1篇
排序方式: 共有27条查询结果,搜索用时 296 毫秒
1.
It is proved that algebraic and topological K-functors are isomorphic on the category of stable generalized operator algebras which are K i -regular for all i > 0.  相似文献   
2.
Coulomb Sturmians are obtained in prolate spheroidal coordinates by separation of variables in the Schrödinger equation and direct solution of the appropriate one-dimensional equations. Molecular orbitals are expressed as linear combinations of the introduced Coulomb Sturmians and some low-lying energy terms and corresponding wave functions are calculated for one-electron diatomic molecules. It is shown that similarity of the one- and two-centre orbitals in spheroidal coordinates, combined with completeness and good convergence properties of Coulomb Sturmians, substantially speeds up convergence and makes the calculated results closer to the exact ones. Application of the elaborated calculating scheme for diatomic many-electron molecules is discussed.  相似文献   
3.
4.
Sodium dithionite in the presence of NaHCO3 in water acts as a single‐electron‐transfer agent and facilitates the single‐electron‐transfer/degenerative‐chain‐transfer mediated living radical polymerization (SET–DTLRP) of acrylates initiated with iodoform at room temperature. The resulting α,ω‐di(iodo)polyacrylates can be used as macroinitiators for the SET–DTLRP of other acrylates. Ultrahigh‐molar‐mass poly(tert‐butyl acrylate) can be synthesized via the SET–DTLRP of tert‐butyl acrylate and has a very low weight‐average molecular weight/number‐average molecular weight ratio of 1.15. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2178–2184, 2005  相似文献   
5.
A new solvent mixture, based on ethanol/reline (EM: eutectic mixture), was investigated for the supplemental activator and reducing agent atom transfer radical polymerization (SARA ATRP) of methyl acrylate (MA) near room temperature, for the first time, affording complete catalyst recovery and reuse. The kinetic results revealed that the polymerizations were controlled, with polymers having narrow molecular weight distributions (? < 1.2). The “living” character of the resultant PMA was confirmed by the synthesis of a well‐defined PMA‐b‐PBA block copolymer. Remarkably, it was demonstrated that the Cu(0)/CuBr2/Me6TREN (Me6TREN: tris[2‐(dimethylamino)ethyl]amine) could be recovered from the final reaction mixture and reused for new successful SARA ATRP of MA, suggesting that the reported system could be very attractive from both the economic and environmental perspectives. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 371–381  相似文献   
6.
7.
Journal of Thermal Analysis and Calorimetry - The stabilizer, which is used during the preparation of Poly(lactide-co-glycolide) (PLGA) nanoparticles (NPs), is of great importance for particle...  相似文献   
8.
This study is focused on the analysis of the dynamics of Earth crust tilting at the Enguri Dam International Test Area (EDITA). We aimed to perform a qualitative and quantitative evaluation of the dynamical properties of Earth tilt time series in the context of the development of a real-time telemetric monitoring system at the Enguri test area. The set of Earth tilt hourly time-series data, recorded during the construction of the Enguri power station and subsequent fill of reservoir (1971–1983), has been analyzed. Modern methods of linear and nonlinear time-series analysis have been used. It has been observed that Earth tilt sequences clearly reveal properties of low-dimensional dynamics. Quantitative changes in the dynamics of tilt generation connected with different stages of anthropogenic influence, such as the construction of the Enguri high dam and reservoir fill, have also been detected. It was shown that these changes are transient, since the character of Earth tilt dynamics has been restored at the end of observation.  相似文献   
9.

Sols of core–shell silver nanoparticles (AgNPs) are synthesized by electrochemical method. The method provides the ability to adjust the particle size by changing both the concentration of oleic acid and the residence time τ0 in the organic phase. We synthesized AgNPs with oleic acid (OA) concentration of 0.25% (AgNPs & 0.25% OA) and 0.75% (AgNPs & 0.75% OA). These nanoparticles have been studied using modern physical–chemical methods. Differential thermal analysis curves indicate the chemical nature of bond ligand in the secondary shell; this conclusion is confirmed by quantum chemical simulation and semi-empirical calculation. In the electron paramagnetic resonance spectra of silver-containing sols AgNPs & 0.25% OA and AgNPs & 0.75% OA complex wide asymmetric signals of 500–800 G and g-factor of 2.09–2.13 are recorded, in addition, in the spectra of AgNPs with bilayer the pronounced ferromagnetic contribution is observed. The change of the oleic acid layers of the particles affects the dimension of the nanocrystallites that are being formed and the manifestation of their magnetism.

Trial registration number and date of registration JCS-P-20-03-0188.R1, 22-Sep-2020 (02-Mar-2020)

Graphic Abstract
  相似文献   
10.
The single‐electron transfer living radical polymerization (SET‐LRP) of methyl acrylate initiated with bromoform (CHBr3) and iodoform (CHI3) and catalyzed by Cu(0)/Me6‐TREN in DMSO at 25 °C provides a reliable method to prepare poly (methyl acrylate) (PMA) with active chain ends and controlled structure that can undergo subsequent functionalization to provide strategies for the synthesis of different block copolymers and other complex architectures. A detailed kinetic and structural analysis was used to assess the scope and the limitations of CHBr3 and CHI3 as initiators under SET‐LRP conditions. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 278–288, 2008  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