全文获取类型
收费全文 | 76篇 |
免费 | 3篇 |
专业分类
化学 | 58篇 |
晶体学 | 4篇 |
力学 | 1篇 |
物理学 | 16篇 |
出版年
2016年 | 1篇 |
2015年 | 1篇 |
2014年 | 1篇 |
2013年 | 1篇 |
2012年 | 5篇 |
2011年 | 7篇 |
2010年 | 2篇 |
2009年 | 1篇 |
2008年 | 7篇 |
2007年 | 6篇 |
2006年 | 11篇 |
2005年 | 6篇 |
2004年 | 4篇 |
2003年 | 2篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1994年 | 2篇 |
1985年 | 1篇 |
1981年 | 1篇 |
1978年 | 1篇 |
1976年 | 2篇 |
1975年 | 4篇 |
1974年 | 1篇 |
1973年 | 3篇 |
1971年 | 1篇 |
1966年 | 1篇 |
1959年 | 1篇 |
1938年 | 1篇 |
1935年 | 2篇 |
排序方式: 共有79条查询结果,搜索用时 31 毫秒
71.
72.
Hennebicq E Pourtois G Scholes GD Herz LM Russell DM Silva C Setayesh S Grimsdale AC Müllen K Brédas JL Beljonne D 《Journal of the American Chemical Society》2005,127(13):4744-4762
The dynamics of interchain and intrachain excitation energy transfer taking place in a polyindenofluorene endcapped with perylene derivatives is explored by means of ultrafast spectroscopy combined with correlated quantum-chemical calculations. The experimental data indicate faster exciton migration in films with respect to solution as a result of the emergence of efficient channels involving hopping between chains in close contact. These findings are supported by theoretical simulations based on an improved Forster model. Within this model, the rates are expressed according to the Fermi golden rule on the basis of (i) electronic couplings that take account of the detailed shape of the excited-state wave functions (through the use of a multicentric monopole expansion) and (ii) spectral overlap factors computed from the simulated acceptor absorption and donor emission spectra with explicit coupling to vibrations (considered within a displaced harmonic oscillator model); inhomogeneity is taken into account by assuming a distribution of chromophores with different conjugation lengths. The calculations predict faster intermolecular energy transfer as a result of larger electronic matrix elements and suggest a two-step mechanism for intrachain energy transfer with exciton hopping along the polymer backbone as the limiting step. Injecting the calculated hopping rates into a set of master equations allows the modeling of the dynamics of exciton transport along the polyindenofluorene chains and yields ensemble-averaged energy-transfer rates in good agreement with experiment. 相似文献
73.
F. H. Scholes A. Bendavid F. L. Glenn M. Critchley T. J. Davis B. A. Sexton 《Journal of Raman spectroscopy : JRS》2008,39(5):673-678
Ag film over nanosphere (AgFON) substrates for surface‐enhanced Raman spectroscopy (SERS) are shown to be ineffective for the detection of proteins in phosphate buffer solution (PBS) because of the decomposition of the substrate resulting in a total loss of SERS activity. However, modification of these substrates with SiO2 overlayers overcomes this problem. The SiO2 overlayers are produced by filtered arc deposition (FAD) and are characterised by atomic force microscopy (AFM). Their porosity is examined using Raman spectroscopy and the detection of cytochrome c and bovine serum albumin in PBS is successfully demonstrated. These findings show promise for the detection of proteins in biologically relevant conditions using Ag‐based SERS substrates. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
74.
A multiple injection method for exerting kinetic control in the synthesis of CdSe nanorods 总被引:1,自引:0,他引:1
The thermolysis reaction of a dual precursor system, comprising one that promotes a controlled nucleation event to produce a rod-shaped nanocrystal template, and the other introduced through a subsequent series of injections that maintain the reaction under kinetic drive, is shown to provide a means of controlling growth of CdSe nanorods with a pre-determined aspect ratio. 相似文献
75.
Gregory D. Scholes Kenneth P. Ghiggino 《Journal of photochemistry and photobiology. A, Chemistry》1994,80(1-3):355-362
The nature of the interactions which promote interchromophore electronic excitation transfer are examined. They are partitioned into direct and relayed components, where direct electronic coupling takes the form of a dipole—dipole interaction at large separations. Factors which modify this interaction at short to intermediate separations are discussed (with particular reference to aromatic polymer systems). The direct interaction is partitioned into coulombic, exchange and penetration terms; the significance of the penetration interaction at close separation (proposed recently for the first time) is elaborated upon here. The relayed interaction involves mediation of all these interactions over lage direct separations via intervening moieties. It is demonstrated, using a model poly(acenaphtylene) dyad as an example, that relayed interactions, mediated via the σ bonds connecting two chromophores, are capable of increasing substantially the rate of electronic excitation transfer. 相似文献
76.
Sienkiewicz A Jaworski M Smith BG Fajer PG Scholes CP 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2000,143(1):144-152
We present a novel dielectric resonator (DR)-based resonant structure that accommodates aqueous sample capillaries in orientations that are either parallel (i.e., side-access) or perpendicular to the direction of an external (Zeeman) magnetic field, B(0). The resonant structure consists of two commercially available X-band DRs that are separated by a Rexolite spacer and resonate in the fundamental TE(01delta) mode. The separator between the DRs is used to tune the resonator to the desired frequency and, by appropriately drilled sample holes, to provide access for longitudinal samples, notably capillaries containing oriented, spin-labeled muscle fibers. In contrast to the topologically similar cylindrical TE(011) cavity, the DR-based structure has distinct microwave properties that favor its use for parallel orientation of lossy aqueous samples. For perpendicular orientation of a dilute (6.25 microM) aqueous solution of IASL spin label, the S/N ratio was at least one order of magnitude better for the side-access DR-based structure than for a standard TE(102) cavity. EPR spectra acquired for maleimide spin-labeled myosin filaments also revealed ca. 10 times better S/N ratio than those obtained with a standard TE(102) cavity. For the side-access DR with sample capillaries oriented either parallel or perpendicular to the external magnetic field, the Q- and filling factors are in good agreement with the theoretical estimates derived from the distribution of magnetic (H(1)) and electric (E(1)) components. 相似文献
77.
Usov OM Grigoryants VM Tagore R Brudvig GW Scholes CP 《Journal of the American Chemical Society》2007,129(39):11886-11887
78.
Collini E Todescato F Ferrante C Bozio R Scholes GD 《Journal of the American Chemical Society》2012,134(24):10061-10070
The possibility to transfer energy between molecular excitons across a metal film up to 150 nm thick represents a very attractive solution to control and improve the performances of thin optoeletronic devices. This process involves the presence of coupled surface plasmon polaritons (SPPs) at the two dielectric-metal interfaces, capable of mediating the interactions between donor and acceptor, located on opposite sides of the metal film. In this Article, the photophysics and the dynamics of an efficient SPP-mediated energy transfer between a suitable dye and a conjugated polymer is characterized by means of steady-state and time-resolved photoluminescence techniques. The process is studied in model multilayer structures (donor/metal/acceptor) as well as in electrically pumped heterostructures (donor/metal cathode/acceptor/anode), to verify the effects of applied electric fields on the efficiency and the dynamics of SPP-mediated energy transfer. A striking enhancement of the overall luminescence was recorded in a particular range of applied bias, suggesting the presence of cooperative effects between optical and electrical stimulations. 相似文献
79.
Andrzej Sienkiewicz Ana Maria da Costa Ferreira Birgit Danner Charles P. Scholes 《Journal of magnetic resonance (San Diego, Calif. : 1997)》1999,136(2):137
We report methodology which combines recently developed dielectric resonator-based, rapid-mix, stopped-flow EPR (appropriate for small, aqueous, lossy samples) with rapid scanning of the external (Zeeman) magnetic field where the scanning is preprogrammed to occur at selected times after the start of flow. This methodology gave spectroscopic information complementary to that obtained by stopped-flow EPR at single fields, and with low reactant usage, it yielded more graphic insight into the time evolution of radical and spin-labeled species. We first used the ascorbyl radical as a test system where rapid scans triggered after flow was stopped provided “snapshots” of simultaneously evolving and interacting radical species. We monitored ascorbyl radical populations either as brought on by biologically damaging peroxynitrite oxidant or as chemically and kinetically interacting with a spectroscopically overlapping nitroxide radical. In a different biophysical application, where a spin-label lineshape reflected rapidly changing molecular dynamics of folding spin-labeled protein, rapid scan spectra were taken during flow with different flow rates and correspondingly different times after the mixing-induced inception of protein folding. This flow/rapid scan method is a means for monitoring early immobilization of the spin probe in the course of the folding process. 相似文献