排序方式: 共有28条查询结果,搜索用时 15 毫秒
11.
A. Bacchetta M. Radici F. Conti M. Guagnelli 《The European Physical Journal A - Hadrons and Nuclei》2010,45(3):373-388
We analytically calculate weighted azimuthal asymmetries in semi-inclusive lepton-nucleon deep-inelastic scattering and Drell-Yan processes, using transverse-momentum-dependent partonic densities obtained in a diquark spectator model. We compare the asymmetries with available preliminary experimental data, in particular for the Collins and the Sivers effect. We make predictions for other cases of interest in running and planned experiments. 相似文献
12.
A holographic technique is used to combine the information content of conventional, 2D tomographic scan images into a full-parallax, 3D reconstruction of the recorded subject. Advantages of the system over the conventional, pseudo-3D reconstructions obtained by computer image processing, or over the direct examination of the scan images by the physician, are a more realistic and detailed information to the observer, as true parallax and physical depth cues are fully maintained. 相似文献
13.
The aim of this study was to develop a technique for performing automatic static headspace analysis of volatiles without a cryogenic device. Reconcentration of solutes was accomplished using a graphitized carbon coated precolumn between two splitting points and stopping carrier gas flow during injection. Chromatographic profiles of volatile compounds from ground coffee compared with split and splitless injections provide confirmation of the good sensitivity of the technique. The analysis of a standard mixture covering a wide range of volatility confirms that the described technique might be useful to achieve enrichement of low volatile headspace compounds, even if discrimination against the various components is present. 相似文献
14.
Davide Barreca Franco Benetollo Simona Garon Eugenio Tondello Pierino Zanella 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(7):e290-e291
The title compound, di‐μ‐diethylamido‐N:N‐bis[chlorodimethyltin(IV)], consists of discrete [Sn2Cl2(CH3)4(C4H10N)2] dimer molecules, with Sn atoms linked by bridging diethylamido groups. The coordination geometry about the metal atom is distorted trigonal bipyramidal, with the two methyl C atoms and one N atom in the equatorial plane, and the Cl and second N atom in axial positions. 相似文献
15.
The paper describes a capillary GC/MS hardware arrangement allowong either:
- (a) on-line injection of sample of gases and vapors coming from dynamic headspace or purg & trap samplers and their subsequent cryofocusing/thermal desorption prior to the analytical capillary column (first column):
- (b) direct injection of liquid samples through a cold on-column injector into a second analytical column (counted in series with the first).
16.
S. Boffi L.Ya. Glozman W. Klink W. Plessas M. Radici R.F. Wagenbrunn 《The European Physical Journal A - Hadrons and Nuclei》2002,14(1):17-21
Results for the proton and neutron electric and magnetic form factors as well as the nucleon axial and induced pseudoscalar
form factors are presented for the chiral constituent-quark model based on Goldstone-boson exchange dynamics. The calculations
are performed in a covariant framework using the point-form approach to relativistic quantum mechanics. The direct predictions
of the model yield a remarkably consistent picture of the electroweak nucleon structure.
Received: 28 February 2002 / Accepted: 14 March 2002 相似文献
17.
Passarelli V Benetollo F Zanella P 《Dalton transactions (Cambridge, England : 2003)》2004,(9):1424-1431
The interaction of dimethyldiaminosilane ligands of general formula SiMe2(NR2)(NR'2)(NR2, NR'2 = NiHPr, NHtBu, NC4H8, NHCH2CH2NMe2) with AlX3 (X = Cl, Me) has been investigated and the synthesis of novel aluminium derivatives is reported, namely AlMe3[SiMe2(NR2)(NR'2)], AlX2[SiMe2(NR)(NR'2)] and AlMe[SiMe2(NR)2], containing the silane ligand as neutral, monoanionic and dianionic species, respectively. Moreover, the solution molecular structures and dynamics have been elucidated via 1D/2D variable temperature NMR spectroscopy showing the influence of the N-substituents of the silane ligand and of the aluminium ancillary ligands. 相似文献
18.
Tetraphenylarsonium chloride was used for the potentiometric titration of R4-nSnCln compounds (R = Me, Et, Pr, Bu, Ph ; n = 2,3) in acetonitrile media. Evidence for penta-coordinated R4-nSnCln+1- complexes was obtained. A stability scale as a function of R groups is given. 相似文献
19.
Paolo Colombo Sergio Custro Pierino Radici 《Journal of polymer science. Part A, Polymer chemistry》1980,18(2):681-689
A transacetalization reaction occurs during the etherification of poly(oxymethylene)diol [α-hydro-ω-hydroxypoly(oxymethylene)] with orthoesters and an important modification of molecular structure takes place. The intermediates formed during the transacetalization reaction are emphasized. The connection between this reaction and the other reactions during the etherification of poly(oxymethylene)diols is discussed. 相似文献
20.
Mandeville J Alarcon R Beck R Bernstein A Bertozzi W Boeglin W Boffi S Cardman L Comfort J Dale D Dodson G Dolfini S Dow K Epstein M Gilad S Görgen J Holtrop M Jordan D Kim W Kowalski S Laszewski R Margaziotis D Martinez D McIlvain T Miskimen R Papanicolas C Radici M Tieger D Turchinetz W Weinstein L Williamson S 《Physical review letters》1994,72(21):3325-3328