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   118篇
  免费   12篇
  国内免费   28篇
化学   151篇
综合类   2篇
物理学   5篇
  2021年   1篇
  2020年   2篇
  2019年   3篇
  2018年   1篇
  2017年   4篇
  2016年   9篇
  2015年   4篇
  2014年   2篇
  2013年   15篇
  2012年   1篇
  2011年   4篇
  2010年   4篇
  2009年   10篇
  2008年   11篇
  2007年   8篇
  2006年   8篇
  2005年   5篇
  2004年   8篇
  2003年   10篇
  2002年   3篇
  2001年   5篇
  2000年   7篇
  1999年   1篇
  1998年   4篇
  1997年   3篇
  1996年   1篇
  1995年   5篇
  1994年   5篇
  1993年   5篇
  1992年   1篇
  1991年   3篇
  1988年   4篇
  1987年   1篇
排序方式: 共有158条查询结果,搜索用时 62 毫秒
1.
Two novel polymeric acceptors based on naphthalene diimide (NDI) and 2.2′‐bithiophene, named as P(NDI2THD‐T2) and P(NDI2TOD‐T2), were designed and synthesized for all polymer solar cells application. The structural and electronic properties of the two acceptors were modulated through side‐chain engineering of the NDI units. The optoelectronic properties of the polymers and the morphologies of the blend films composed of the polymer acceptors and a donor polymer PTB7‐Th were systemically investigated. With thiophene groups introduced into the side chains of the NDI units, both polymers showed wider absorption from 350 nm to 900 nm, compared with the reference polymer acceptor of N2200. No redshift of absorption spectra from solutions to films indicated reduced aggregation of the polymers due to the steric hindrance effect of thiophene rings in the side chains. The photovoltaic performance were characterized for devices in a configuration of ITO/PEDOT:PSS/PTB7‐Th:acceptors/2,9‐bis(3‐(dimethylamino)propyl)anthra[2,1,9‐def:6,5,10‐def]diisoquinoline‐1,3,8,10(2H,9H)‐tetraone (PDIN)/Al. With the addition of diphenyl ether as an additive, the power conversion efficiencies (PCEs) of 2.73% and 4.75% for P(NDI2THD‐T2) and P(NDI2TOD‐T2) based devices were achieved, respectively. The latter showed improved Jsc, Fill Factor (FF), and PCE compared with N2200 based devices. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3679–3689  相似文献   
2.
环氧树脂增韧改性的研究进展   总被引:1,自引:0,他引:1  
概述了近年来互穿聚合物网络(IPN)、刚性粒子增韧环氧树脂的研究现状,并展望了环氧树脂增韧改性研究的前景。  相似文献   
3.
In this article, we report on the viscoelastic and thermal properties of agarose–polyacrylamide (PAAm) interpenetrating polymer hydrogels (IPHs) and semi‐IPHs as a function of agarose concentration and PAAm crosslinking degree. The results demonstrated that the agarose is able to gel in the presence of crosslinked and linear IPHs. In addition, the reticulation of PAAm in the presence of agarose is confirmed for the case of IPHs giving rise to systems with dimensional stability at high temperatures. The formation of a fully IPH was ascertained at low agarose concentrations. A study of the morphology and nanoscale elasticity of the different systems has been carried out with atomic force microscopy/ultrasonic force microscopy (UFM). UFM data provide further evidence of interpenetration, allowing us to visualize—if present—phase‐separated domains with nanoscale resolution for the various crosslinking degrees and PAAm and agarose concentrations used during the formation of the IPHs. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2010  相似文献   
4.
Vertically aligned ZnO nanorods (NR) are prepared by two different syntheses methods and applied on polymer solar cells (PSCs). The ZnO electrodes work as the electron transport layer with the P3HT:PCBM blend acting as the active material. Several organic blend solution conditions are optimized: concentration, solvent, and deposition speed. The effect of different NR electrode morphologies is analyzed on the solar cell performance and characterized by current–voltage curves and IPCE analyses. The photovoltaic performance of the solar cells was observed to be influenced by many factors, among them infiltration of the organic P3HT:PCBM blend within the ZnO NR layer. The infiltration of the active layer was monitored by cross section SEM and energy dispersive X-ray spectroscopy analyses. Our results show that higher power conversion efficiencies are achieved when shorter NRs lengths are applied. The best power conversion efficiency obtained was 2.0% for a 400 nm ZnO NR electrode. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2013  相似文献   
5.
In this work, acrylamide/itaconic acid copolymeric hydrogels are prepared by free radical polymerization initiated by redox initiators of potassium persulfate and N ,N ,N ′,N ′‐tetramethyl ethylene diamine; N ,N ′methylene bisacrylamide was employed as a crosslinking agent. Aniline monomer was absorbed in the network of poly(acrylamide‐co‐itaconic acid) P(AAm‐co‐IA) hydrogel and followed by gamma radiation induced polymerization at room temperature. The novel semi‐interpenetrating network was comprised of linear polyaniline immersed in P(AAm‐co‐IA) matrix. Electrical conductivity of the hydrogels was measured using four‐probe technique. The conductivities for the prepared hydrogels are found to increase from 5.5 × 10?7 S cm?1 for P(AAm‐co‐IA) alone to 4.4 × 10?3 S cm?1 for semi‐interpenetrating polymer network P(AAm‐co‐IA)/polyaniline. Thus, a new composite hydrogel with good conductive properties also displaying enhanced mechanical strength and pH sensitivity was prepared. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   
6.
高分子阴离子电导的研究   总被引:8,自引:0,他引:8  
制备了含I^-榻解质薄膜,用阻抗谱法测量了样品的I^-电导率,分析了样品的频响特性曲线,用Wagner直流极化法测量了样品的电子电导。实验发现,此阴离子导体几乎和相应的含Na^+有相同的离子电导率,且随着碘含量的增加, 率增大。离子电导实验结果表明,在此阴离子导体中,电子电导占总电导率的9%,而空穴的导导率比电子电导率小1 ̄2个数量级。  相似文献   
7.
In this study NMR and DSC are used to probe the structure, thermal characteristics and morphology of a network formed from a diepoxide/acrylate system. Separate chemistries are employed to polymerize the diepoxide and acrylate components. The cationic polymerization of the diepoxide exhibits excellent selectivity in producing a crosslinked polyether network without affecting the acrylate monomer. Subsequent photoinitiated free-radical polymerization of the acrylate produces a phase separated, semi-interpenetrating polymer network (SIPN).This revised version was published online in November 2005 with corrections to the Cover Date.  相似文献   
8.
《Composite Interfaces》2013,20(8-9):539-566
This review focuses on some aspects of organic-inorganic hybrid materials prepared by the sol-gel method. This field has been studied worldwide as one of the nanotechnologies, and is now of current interest for both organic and inorganic scientists. The elaboration of organic–inorganic polymer hybrid materials using the sol-gel process can be accomplished by various approaches. The simplest method is increasing the compatibility by using physical interactions, covalent bonding and compatibilizer between organic polymer and silica gel. Other novel approaches, such as an in-situ method, NHSG (Non- Hydrolysis Sol-Gel) process, and use of reactive polymer hybrids resulted in the preparation of novel transparent organic–inorganic polymer hybrid materials. Stimulus responsive polymer hybrids are also mentioned. Furthermore, nano-structured organic–inorganic polymer hybrids are created by using supermolecular and self-assembly of organic molecules or polymers recently. The obtained nano-structured hybrid materials showed unique properties that could not be found in amorphous hybrid materials. The possibilities and applications of organic–inorganic polymer hybrid materials are also described in this review.  相似文献   
9.
10.
Thermal transitions of benzene in a hydrophobic polymer network have been explained by us in terms of the phase diagram of the polymer‐solvent system. In this work, we executed a similar study on copolymers and interpenetrating polymer networks (IPNs) with controllable hydrophilic/hydrophobic ratios. Copolymers and IPNs were swollen with different amounts of benzene and subjected to cooling and heating scans with differential scanning calorimetry (DSC). Synthesis of the IPNs was carried out in such a way that phase separation appeared, and three qualitatively different types of DSC thermograms were identified depending on the benzene content of IPN. Thermal transitions of benzene in the hydrophilic/hydrophobic copolymers can also be explained as a consequence of the phase diagram of the system, but an increase in the glass‐transition temperature of the system can be correlated with the interactions among the hydrophilic groups of the copolymer. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1713–1721, 2003  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