全文获取类型
收费全文 | 146篇 |
免费 | 7篇 |
国内免费 | 5篇 |
专业分类
化学 | 35篇 |
综合类 | 2篇 |
物理学 | 121篇 |
出版年
2023年 | 2篇 |
2022年 | 1篇 |
2021年 | 2篇 |
2020年 | 2篇 |
2019年 | 3篇 |
2018年 | 1篇 |
2017年 | 2篇 |
2016年 | 3篇 |
2015年 | 4篇 |
2014年 | 1篇 |
2013年 | 6篇 |
2012年 | 2篇 |
2011年 | 9篇 |
2010年 | 10篇 |
2009年 | 16篇 |
2008年 | 13篇 |
2007年 | 21篇 |
2006年 | 20篇 |
2005年 | 9篇 |
2004年 | 3篇 |
2003年 | 4篇 |
2002年 | 3篇 |
2001年 | 5篇 |
2000年 | 4篇 |
1999年 | 5篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1996年 | 1篇 |
1995年 | 1篇 |
排序方式: 共有158条查询结果,搜索用时 288 毫秒
11.
Atsuhiro Fujimori Hiroko Hoshizawa Satoshi Kobayashi Kaname Kanai Yukio Ouchi Kazuhiko Seki 《Journal of Polymer Science.Polymer Physics》2008,46(5):534-546
Comb copolymers containing both hydrogenated and fluorinated side‐chains were prepared by copolymerization using acrylic or methacrylic monomers in several ratios. The crystal structures of these copolymers and layer structures of their organized molecular films were investigated by wide‐angle X‐ray diffraction (WAXD), small‐angle X‐ray scattering (SAXS), and out‐of plane X‐ray diffraction. Further, to selectively estimate the regularity of shorter fluorocarbon side‐chains, organized molecular films of copolymers were investigated by polarized near‐edge X‐ray adsorption fine structure (NEXAFS) spectroscopy. From the results of these measurements, it was inferred that these copolymers formed highly ordered layer structures, and a long spacing was predominantly determined by the arrangement of hydrogenated side‐chains, except in copolymers having extremely high fluorocarbon contents. In the case of the organized molecular films, the fluorinated side‐chains of methacrylate copolymers cannot form a highly ordered arrangement, whereas those of acrylate copolymers were oriented on monolayers. However, in both cases, the hydrogenated side‐chains predominantly formed layer structures in the organized films, and the fluorinated side‐chains did not contribute to the formation of the layer structures. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 534–546, 2008 相似文献
12.
N.E. Rajeevan Ravi KumarD.K. Shukla R.J. ChoudharyP. Thakur A.K. SinghS. Patnaik S.K. AroraI.V. Shvets P.P. Pradyumnan 《Journal of magnetism and magnetic materials》2011,323(13):1760-1765
Thin films of BixCo2−xMnO4 (x=0, 0.1 and 0.3) were grown on quartz, LaAlO3 (LAO) and YBa2Cu3O7 (YBCO) buffer layer coated LAO substrates by pulsed laser deposition (PLD). X-ray diffraction (XRD) and Raman scattering measurements showed that the thin films exhibit single phase polycrystalline cubic spinel structure on all the substrates. Near edge X-ray absorption fine structure (NEXAFS) studies confirmed the octahedral occupancy of the substituted Bi3+ ions. Temperature dependent zero-field cooled (ZFC) magnetization measurements show the ferrimagnetic (FM) behavior (TC∼186 K) and magnetization undergoes a crossover from positive to negative, owing to the opposite contributions of magnetic moments from Co and Mn ions. A weak ferroelectric property exhibited by the films above room temperature was evidenced through the capacitance-voltage (C-V) and dielectric measurements. Magnetoelectric coupling was found to be maximum just below FM-TC. 相似文献
13.
We present a spectroscopic study of the structure of two peptides deposited on Au and TiO2:
- - PeptA, (EAK16-RGD) bringing the adhesive RGD sequence linked to EAK16;
- - PeptB, having RGD linked to a “scrambled” sequence of the EAK16 peptide.
14.
《Composite Interfaces》2013,20(2-3):127-136
Polyurethane (PU) and polystyrene (PS) films were functionalized by ultraviolet (UV) or selective synchrotron radiations (SR) in the presence of reactive gases. The UV-PU results were compared with lowpressure plasma treatments of the same films. Oxygen or acrylic acid vapours (AA) were used as reactive gases. X-ray photoelectron spectroscopy measurements of UV modified films in the presence of oxygen or AA matched the RF-plasma treatments results. It is shown that COO and C=O functional groups were incorporated at the polymer surface efficiently with both methodologies. In addition, near-edge X-ray absorption fine structure showed that a thin film of poly(acrylic acid) is formed over the PU and PS films during the UV irradiation in the presence of AA vapours. These results resemble previous AA low-power plasma treatments. PU and PS films were also selectively functionalized by SR using oxygen as reactive gas. Surface concentrations of COO and C=O functional groups were enhanced by C1s → σ* C–C excitation after irradiation and oxygen introduction. This efficient surface functionalization was clearly observed in PS films which do not have CO and COO groups in their molecular structure. Excitations involving transitions to π* orbital (π*C=C, π*C=O) led to much lower functionalization efficiency. The SR results can be explained by taking into account previous photon stimulated ion desorption studies of polymers. SR results may open new ways to functionalize polymer surfaces selectively and efficiently. 相似文献
15.
Michael X. Yang Phillip W. Kash Dong-Hong Sun George W. Flynn Brian E. Bent Michael T. Holbrook Simon R. Bare Daniel A. Fischer John L. Gland 《Surface science》1997,380(2-3):151-164
The bonding and reactions of chloroethylenes (vinyl chloride, trans- and cis-dichloroethylene, trichloroethylene) on a Cu(100) surface have been investigated by temperature-programmed desorption and reaction, near-edge X-ray absorption fine structure (NEXAFS) studies and measurements of changes of the surface work function. The monolayer molecules adsorb molecularly intact at 95 K via π coordination. The molecules orient with their molecular planes parallel to the surface with little increase (<0.02 Å) in the C---C bond distance compared with the gas phase values. The degree of thermal dissociation increases with the extent of halogenation, and no chlorine is present in the hydrocarbon reaction products liberated from the surface. Both cis- and trans-1.2-chloroethylene produce acetylene and a small amount of benzene, while dissociation of trichloroethylene generates acetylene and deposits a carbon residue on the surface. Vinyl chloride desorbs from Cu(100) without reaction. 相似文献
16.
J. Zhou 《Surface science》2006,600(7):1540-1546
Formaldehyde adsorption and reaction have been studied on cerium oxide thin films that were vapor deposited on Ru(0 0 0 1). The formaldehyde behavior was examined as a function of temperature, exposure and Ce oxidation state. Formaldehyde chemisorbs on fully oxidized CeO2 as dioxymethylene, CH2O2. The dioxymethylene decomposes and desorbs as formaldehyde between 200 K and 400 K. No other products are formed. On reduced ceria, formaldehyde also adsorbs as dioxymethylene. In addition to the formaldehyde desorption between 200 K and 400 K, a more strongly bound form of dioxymethylene is formed that produces formaldehyde at 440 K. Above 400 K, some of the dioxymethylene reacts to form formate and methoxy on the surface. These species decompose to produce H2, CO and CH2O above 500 K. 相似文献
17.
利用X射线光电子能谱(XPS),同步辐射紫外光电子能谱(SRUPS),近边X射线吸收精细结构(NEXAFS)以及原子力显微镜(AFM)等技术研究了苝四甲酸二酐(PTCDA)与Au(111)的界面电子结构、PTCDA分子取向及有机薄膜的表面形貌.SRUPS价带谱显示,伴随PTCDA分子的微量沉积(0·5ML),位于费米能级附近Au的表面电子态迅速消失,但却观察不到明显的界面杂化态,这说明PTCDA分子和Au(111)界面间存在弱电子传输过程,但并没有发生明显的化学反应.角分辨NEXAFS以及SRUPS结果证明PTCDA分子是平铺在衬底表面.根据Au4f7/2和C1s峰积分强度随薄膜厚度的变化以及AFM图像可知,PTCDA分子在Au(111)表面是一种典型的Stranski-Krastanov生长模式,即先层状生长,再岛状生长,并且在层状生长到岛状生长的转变过程中,存在有机分子的去润湿过程. 相似文献
18.
Well-defined and homogeneous, contamination-free self-assembled monolayers (SAMs) were fabricated by the chemisorption of lip-NH-p-C6H4-NN-p-C6H4-COOH (lip = α-lipoyl) onto gold. This adsorbate species is composed of a 1,2-dithiolane-based headgroup, an azobenzene-based (and hence photochromic) spacer unit and a carboxylic acid functional group. The SAM constituents are covalently attached to the substrate by the bidentate thiolate anchor groups and exhibit a strongly tilted binding configuration. 相似文献
19.
Masahito Tagawa Kumiko Yokota Koji Matsumoto Yuden Teraoka Masahito Niibe 《Applied Surface Science》2010,256(24):7678-7683
Surface structural changes of a hydrogenated diamond-like carbon (DLC) film exposed to a hyperthermal atomic oxygen beam were investigated by Rutherford backscattering spectroscopy (RBS), synchrotron radiation photoelectron spectroscopy (SR-PES), and near-edge X-ray absorption fine structure (NEXAFS). It was confirmed that the DLC surface was oxidized and etched by high-energy collisions of atomic oxygen. RBS and real-time mass-loss data showed a linear relationship between etching and atomic oxygen fluence. SR-PES data suggested that the oxide layer was restricted to the topmost surface of the DLC film. NEXAFS data were interpreted to mean that the sp2 structure at the DLC surface was selectively etched by collisions with hyperthermal atomic oxygen, and an sp3-rich region remained at the topmost DLC surface. The formation of an sp3-rich layer at the DLC surface led to surface roughening and a reduced erosion yield relative to the pristine DLC surface. 相似文献
20.
We investigate the relation between the optical properties and the average molecular tilt angle for blends of pentacene and perfluoropentacene, which can be considered as a prototypical donor–acceptor complex. Combining near‐edge X‐ray absorption fine‐structure spectroscopy and optical spectroscopy we study thin films of these compounds prepared at three different substrate temperatures Tsub. For Tsub =180 K we observe a larger average tilt angle than for blends prepared at higher substrate temperatures. This orientational change has significant impact on the uniaxial anisotropic optical properties of the mixed films which we measure post growth as well as in real‐time during growth. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献