全文获取类型
收费全文 | 65篇 |
免费 | 1篇 |
专业分类
化学 | 21篇 |
数学 | 6篇 |
物理学 | 39篇 |
出版年
2022年 | 1篇 |
2020年 | 2篇 |
2017年 | 1篇 |
2014年 | 1篇 |
2013年 | 4篇 |
2012年 | 2篇 |
2010年 | 2篇 |
2009年 | 3篇 |
2008年 | 4篇 |
2007年 | 6篇 |
2006年 | 4篇 |
2005年 | 3篇 |
2004年 | 1篇 |
2003年 | 2篇 |
2002年 | 3篇 |
2001年 | 3篇 |
2000年 | 2篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 3篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 3篇 |
1983年 | 4篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有66条查询结果,搜索用时 538 毫秒
41.
Damas A Ventura B Axet MR Esposti AD Chamoreau LM Barbieri A Amouri H 《Inorganic chemistry》2010,49(23):10762-10764
The synthesis, X-ray structure determination, and photophysical investigation of a novel series of heteroleptic ruthenium(II) polypyridine complexes with organometallic linkers are reported. The displayed panchromatic absorption features are assigned by means of time-dependent density functional theory studies. 相似文献
42.
Claudio Degli Esposti Luca Dore Luciano Fusina Filippo Tamassia 《Molecular physics》2013,111(7):896-902
The pure rotational spectrum of 13C2HD was recorded in the range 100–700 GHz. Lines belonging to the ground vibrational state were observed from J″ = 1 to J″ = 11. Several absorption lines were also detected in the bending states v4 = 1 (Π), v5 = 1 (Π), v4 = 2 (Σ+ and Δ), v5 = 2 (Σ+ and Δ), v4 = v5 = 1 (Σ?, Σ+ and Δ), v4 = 3 (Π and Φ) and v5 = 3 (Π and Φ). The transition frequencies measured in this work were fitted together with all the infrared lines available in the literature. The global fit allowed a very accurate determination of the vibrational, rotational and ?-type interaction parameters for the bending states of this molecule. 相似文献
43.
In some dynamical problems one may need to perform repeatedly non numerical calculations on algebraic expressions. In such a case one can use the FORMAC system which allows to carry out algebraic calculations on a digital computer. Since we have afforded this problem in one particular case, we wish to illustrate this application of FORMAC in order to bring to the attention of chemical physicists the existence of such computational technique. 相似文献
44.
L. Campos Venuti C. Degli Esposti Boschi E. Ercolessi G. Morandi F. Ortolani S. Pasini M. Roncaglia 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,53(1):11-18
Motivated by field-theoretic predictions we investigate the stable
excitations that exist in two characteristic gapped phases of a spin-1
model with Ising-like and single-ion anisotropies. The sine-Gordon
theory indicates a region close to the phase boundary where a stable
breather exists besides the stable particles, that form the Haldane
triplet at the Heisenberg isotropic point. The numerical data, obtained
by means of the Density Matrix Renormalization Group, confirm this
picture in the so-called large-D phase for which we give also a
quantitative analysis of the bound states using standard perturbation
theory. However, the situation turns out to be considerably more intricate
in the Haldane phase where, to the best of our data, we do not observe
stable breathers contrarily to what could be expected from the sine-Gordon
model, but rather only the three modes predicted by a novel anisotropic
extension of the Non-Linear Sigma Model studied here by means of a
saddle-point approximation. 相似文献
45.
Summary The millimetre wave spectrum of the32S17O free radical has been observed and analysed. The fine- and hyperfine-structure parameters have been determined. Ther
s andr
m structures have been also determined.
To speed up publication, the authors of this paper have agreed to not receive the proofs for correction.
The supporting organizations are the CNR and the M.P.I. 相似文献
Riassunto è stato osservato ed analizzato lo spettro millimetrico del radicale libero32S17O. Sono stati determinati i parametri di struttura fine ed iperfine e le strutturer s er m.
Резюме Наблюдался д проведен анализ спектра миллиметровых волн свободного радикала32З17О. Определены параметры тонкой и сверхтонкой структуры. Также определены структурыr s иr m.
To speed up publication, the authors of this paper have agreed to not receive the proofs for correction.
The supporting organizations are the CNR and the M.P.I. 相似文献
46.
Fabrizio Cavani Prof. Silvia Luciani Dr. Elisa Degli Esposti Carlotta Cortelli Roberto Leanza 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(5):1646-1655
This work focused on investigating the effect of the P/V atomic ratio in vanadyl pyrophosphate, catalyst for n‐butane oxidation to maleic anhydride, on the nature of the catalytically active phase. Structural transformations occurring on the catalyst surface were investigated by means of in situ Raman spectroscopy in a non‐reactive atmosphere, as well as by means of steady‐state and non‐steady‐state reactivity tests, in response to changes in the reaction temperature. It was found that the nature of the catalyst surface is affected by the P/V atomic ratio even in the case of small changes in this parameter. With the catalyst having P/V equal to the stoichiometric value, a surface layer made of αI‐VOPO4 developed in the temperature interval 340–400 °C in the presence of air; this catalyst gave a very low selectivity to maleic anhydride in the intermediate T range (340–400 °C). However, at 400–440 °C δ‐VOPO4 overlayers formed; at these conditions, the catalyst was moderately active but selective to maleic anhydride. With the catalyst containing a slight excess of P, the ratio offering the optimal catalytic performance, δ‐VOPO4 was the prevailing species over the entire temperature range investigated (340–440 °C). Analogies and differences between the two samples were also confirmed by reactivity tests carried out after in situ removal and reintegration of P. These facts explain why the industrial catalyst for n‐butane oxidation holds a slight excess of P; they also explain discrepancies registered in the literature about the nature of the active layer in vanadyl pyrophosphate. 相似文献
47.
Normal and deuterated isotopic variants of thioborine have been produced in the gas phase by a high temperature reaction between crystalline boron and hydrogen sulfide. Millimeter- and submillimeter-wave rotational spectra have been recorded in the frequency range from 75 to 730 GHz for vibrational ground and excited states of the H10/11B32S and D10/11B32S isotopic species. The spectra of all the excited states which lie below 1500 cm−1, that are 0110, 0001, 0200, and 0220, have been observed and analyzed for each of the four isotopologues investigated. High-order Fermi resonance parameters were found important to analyze properly the spectra of the 0001 and 0200 interacting states. The improved rotational data in conjunction with earlier infrared spectroscopy results have been employed to calculate more precise anharmonic force constants and equilibrium bond lengths. 相似文献
48.
The rotational spectra of (32)S(35)Cl(2), (32)S(35)Cl(37)Cl, (32)S(37)Cl(2), and (34)S(35)Cl(2) in their ground vibrational states, as well as those of (32)S(35)Cl(2) and (32)S(35)Cl(37)Cl in their nu(2) and 2nu(2) excited states, have been studied in selected frequency regions between 100 and 370 GHz. Transitions involving a large range of quantum numbers have been observed, so that precise rotational and quartic centrifugal distortion constants could be determined for each of the spectra investigated. The complete set of sextic distortion constants was also obtained for the most abundant isotopomer in its ground vibrational state. The newly determined rotational constants of (34)S(35)Cl(2) and (32)S(37)Cl(2) allowed us to calculate the complete r(s) structure of sulfur dichloride using both single- and double-isotopic substitution methods. The quadratic force field has been refined using a larger set of quartic distortion constants and inertial defects. Copyright 2000 Academic Press. 相似文献
49.
The rotational spectrum of the unstable ClBS molecule has been investigated in the millimeter-wave region, from 80 to 195 GHz. A high-temperature reaction between crystalline boron and disulfur dichloride vapor was used to produce the molecule in a flow pyrolysis system. Eight different isotopic species were studied measuring lines in the ground and excited vibrational states 0110 (ClBS bend), 1000 (ClB stretch), 0200, 0220, and 0001 (BS stretch). The analysis of the spectra has been performed taking simultaneously into account both the Fermi resonance between the 1000 and 0200 states, and l-type resonance effects in the v2=2 vibrational state. This procedure allowed us to calculate directly deperturbed rotational constants, from which the equilibrium rotational constant of seven isotopic variants could be accurately determined yielding a much improved evaluation of the equilibrium structure of chlorothioborine: re(ClB)=1.6806±0.0001 Å and re(BS)=1.6049±0.0001 Å. The equilibrium structures of ClBS and of the related molecules HBS, FBS, HCP, FCP, and ClCP have been also theo-retically evaluated by high-level CCSD(T) calculations performed using cc-pVTZ, cc-pVQZ, and cc-pV5Z basis sets. The different trends respectively observed for the BS and CP bond lengths in the XBS and XCP triatomic molecules are discussed. 相似文献
50.
Summary Thorello is a steady-state toroidal magnetized plasma suitable for basic plasma physics experiments. The discharge is produced
in hydrogen by hot-filament electron emission and acceleration by a bias. Electron temperature and density have been evaluated
by electrostatic probes. Excitation and detection by an interferometric method of electrostatic ion cyclotron waves (ESICW)
have permitted the evaluation of ion temperature.
Riassunto Thorello è un plasma magnetizzato stazionario particolarmente adatto per esperimenti di fisica del plasma di base. La scarica è prodotta in idrogeno per mezzo di elettroni emessi da un filamento caldo ed accelerati da una differenza di potenziale. La temperatura e la densità elettronica sono state valutate per mezzo di sonde elettrostatiche. La temperatura ionica è stata ricavata mediante un metodo interferometrico basato sull’eccitazione e la rilevazione di onde elettrostatiche ioniche di ciclotrone (ESICW).相似文献