全文获取类型
收费全文 | 77篇 |
免费 | 0篇 |
专业分类
化学 | 30篇 |
晶体学 | 1篇 |
数学 | 5篇 |
物理学 | 41篇 |
出版年
2021年 | 1篇 |
2020年 | 1篇 |
2016年 | 3篇 |
2015年 | 1篇 |
2013年 | 5篇 |
2012年 | 3篇 |
2010年 | 3篇 |
2009年 | 3篇 |
2008年 | 5篇 |
2007年 | 7篇 |
2006年 | 1篇 |
2005年 | 1篇 |
2002年 | 1篇 |
2001年 | 2篇 |
2000年 | 4篇 |
1999年 | 6篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 5篇 |
1994年 | 2篇 |
1989年 | 1篇 |
1986年 | 2篇 |
1984年 | 4篇 |
1983年 | 1篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1974年 | 2篇 |
排序方式: 共有77条查询结果,搜索用时 0 毫秒
1.
Manca F Giordano S Palla PL Zucca R Cleri F Colombo L 《The Journal of chemical physics》2012,136(15):154906
Stretching experiments on single molecules of arbitrary length opened the way for studying the statistical mechanics of small systems. In many cases in which the thermodynamic limit is not satisfied, different macroscopic boundary conditions, corresponding to different statistical mechanics ensembles, yield different force-displacement curves. We formulate analytical expressions and develop Monte Carlo simulations to quantitatively evaluate the difference between the Helmholtz and the Gibbs ensembles for a wide range of polymer models of biological relevance. We consider generalizations of the freely jointed chain and of the worm-like chain models with extensible bonds. In all cases we show that the convergence to the thermodynamic limit upon increasing contour length is described by a suitable power law and a specific scaling exponent, characteristic of each model. 相似文献
2.
A detailed analysis of the proton high-field NMR spectra of vinegars (in particular of Italian balsamic vinegars) is reported. A large number of organic substances belonging to different classes, such as carbohydrates, alcohols, organic acids, volatile compounds and amino acids, were assigned. The possibility of quantification of the substances identified in the whole vinegar sample, without extraction or pre-concentration steps, was also tested. The data validity was demonstrated in terms of precision, accuracy, repeatability and inter-day reproducibility. The effects of the most critical experimental parameters (sample concentration, water suppression and relaxation time) on the analysis response were also discussed. 1H NMR results were compared with those obtained by traditional techniques (GC-MS, titrations), and good correlations were obtained. The results showed that 1H NMR with water suppression allows a rapid, simultaneous determination of carbohydrates (glucose and fructose), organic acids (acetic, formic, lactic, malic, citric, succinic and tartaric acids), alcohols and polyols (ethanol, acetoin, 2,3-butanediol, hydroxymethylfurfural), and volatile substances (ethyl acetate) in vinegar samples. On the contrary, the amino acid determination without sample pre-concentration was critical. The 1H NMR method proposed was applied to different samples of vinegars, allowing, in particular, the discrimination of vinegars and balsamic vinegars. 相似文献
3.
4.
V. Dinca A. Palla?Papavlu A. Matei C. Luculescu M. Dinescu T. Lippert F. Di Pietrantonio D. Cannata M. Benetti E. Verona 《Applied Physics A: Materials Science & Processing》2010,98(2):429-434
This paper presents a comparative study of polymer pixel on sensors obtained by Laser Induced Forward Transfer (LIFT) assisted
by a triazene polymer as Dynamic Release Layer (DRL). Polyisobutylene (PIB) was selected as model for chemoselective polymers
which could be used as hydrogen-bond acidic polymer for vapor sensors. 相似文献
5.
It is shown that in the one loop order of perturbation theory the coupling constant and parameter(s) of an (Abelian T) dual sigma model get renormalized in the same way as in the ‘original’ model. 相似文献
6.
L. Palla 《Zeitschrift fur Physik C Particles and Fields》1984,24(2):195-204
We compare the four-dimensional symmetric fields obtained by the coset space dimensional reduction scheme to the infinite tower of fields given by the harmonic expansion in a 4+N dimensional gauge theory coupled to fermions on a space-timeM 4 ×S/R. 相似文献
7.
The minimum energy path and the geometry of the transition state for the first stage of the reduction by LiBH4 of R2CO (RH, CH3) to alcohol have been determined by ab initio SCF calculations using a small basis set and subsequently confirmed by further calculations using a larger basis set and CI methods. Attention has been focused on the changes of electron distribution during the reaction, the nature of the bonding, and the effect of chemical substituents. The results lend support to one of the proposed reaction mechanisms. Some supplementary data concerning the role of the solvent are also discussed. 相似文献
8.
The electromagnetic mass shift of pions is discussed in unified gauge field theories of weak and electromagnetic interactions to second order of the electric charge and the pion mass, respectively. We calculate the contributions of the next to leading light-cone singularities (quark mass terms) and it is found that these do not contribute to the divergences in the mass shift provided the masses of the bare proton quark and neutron quark are equal. γ, Z, W, φ exchanges are taken into account. Different bare quark masses in general make the mass shift divergent. In the tadpole contribution, the Born term causes a divergence unless we extrapolate first to q2 = 0. 相似文献
9.
A family of 4n?1 parameter solutions corresponding to n monopoles is constructed by a three-dimensional “inverse scattering” method. Global regularity of the finitely separated two-monopole solution is shown. 相似文献
10.
Antonella Casoli Piero Mirti Gerardo Palla 《Fresenius' Journal of Analytical Chemistry》1995,352(3-4):372-379
Proteinaceous organic materials used as ancient painting media were investigated by capillary gas chromatography (GC) and capillary gas chromatography — mass spectrometry (GC/MS). Medieval wall paintings made by the tempera technique were considered and their binding media were studied by the characterization of their main chemical components. The basic methodology is based on the determination of amino acids in samples of paint layers after hydrolysis and derivatization and on the comparison with reference proteinaceous materials. Multivariate chemometric techniques were used to facilitate the recognition of the protein source from chromatographic data. To characterize the binders further, a method was developed for the determination of fatty acids, present as minor components, by GC/MS. The use of fused-silica capillary columns coated with selected stationary phases allowed the separation of amino acid and fatty acid derivatives in a single analytical run. 相似文献