全文获取类型
收费全文 | 117篇 |
免费 | 4篇 |
专业分类
化学 | 58篇 |
力学 | 5篇 |
数学 | 28篇 |
物理学 | 30篇 |
出版年
2022年 | 1篇 |
2021年 | 1篇 |
2020年 | 1篇 |
2019年 | 2篇 |
2018年 | 5篇 |
2017年 | 3篇 |
2016年 | 1篇 |
2015年 | 5篇 |
2014年 | 3篇 |
2013年 | 8篇 |
2012年 | 10篇 |
2011年 | 8篇 |
2010年 | 4篇 |
2009年 | 5篇 |
2008年 | 7篇 |
2007年 | 8篇 |
2006年 | 4篇 |
2005年 | 7篇 |
2004年 | 7篇 |
2003年 | 7篇 |
2002年 | 5篇 |
2001年 | 2篇 |
1999年 | 4篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1975年 | 1篇 |
排序方式: 共有121条查询结果,搜索用时 46 毫秒
21.
N2-broadening coefficients are measured for 61 transitions of PH3 in the QR branch of the ν2 band and the PP, RP, SP, and PQ branches of the ν4 band, using a tunable diode-laser spectrometer. The recorded lines with J values ranging from 1 to 16 and K from 0 to 11 are located between 1008 and 1106 cm−1. The collisional widths are determined by fitting each spectral line with a Voigt profile, a Rautian profile, and a speed-dependent Rautian profile. The latter models provide larger broadening coefficients than the Voigt model. These coefficients have also been calculated on the basis of a semiclassical model of interacting linear molecules by considering an atom-atom Lennard-Jones potential in addition to the electrostatic contributions. The theoretical results are in good agreement with the experimental data and reproduce the J dependence of the broadenings, but their decrease at high J values is overestimated for the QR (J, K) transitions. 相似文献
22.
Global and local Weyl modules were introduced via generators and relations in the context of affine Lie algebras in [CP2] and were motivated by representations of quantum affine algebras. In [FL] a more general case was considered by replacing the polynomial ring with the coordinate ring of an algebraic variety and
partial results analogous to those in [CP2] were obtained. In this paper we show that there is a natural definition of the local and global Weyl modules via homological
properties. This characterization allows us to define the Weyl functor from the category of left modules of a commutative
algebra to the category of modules for a simple Lie algebra. As an application we are able to understand the relationships
of these functors to tensor products, generalizing results in [CP2] and [FL]. We also analyze the fundamental Weyl modules and show that, unlike the case of the affine Lie algebras, the Weyl functors
need not be left exact. 相似文献
23.
Ghislain R. Franssens 《Applicable analysis》2013,92(3):333-356
This is the second in a series of two papers in which we construct a convolution product for the set ?′ (R) of associated homogeneous distributions (AHDs) with support in R. In Part I we showed that if f a and g b are AHDs with degrees of homogeneity a ? 1 and b ? 1, the convolution f a * g b exists as an AHD, if the resulting degree of homogeneity a + b?1 ? N. In this article, we develop a functional extension process, based on the Hahn–Banach theorem, to give a meaning to the convolution product of two AHDs of degrees a ? 1 and b ? 1, in the critical case that a + b ? 1 ∈ N. With respect to this construction, the structure (?′(R), *) is shown to be closed. 相似文献
24.
Absorption and emission spectroscopy as well as laser flash photolysis was employed in order to characterize the spectral
properties of novel probes based on benzothioxantheneimide chromophore covalently linked with different types of sterically
hindered amines. These were chosen as 2-(2,2,6,6-tetramethyl-4-piperidyl)-thioxantheno[2,1,9-dej]isoquinoline-1,3-dione (BTXINH),
the equivalent stable nitroxyl radical, i.e. 2-(1-oxo-2,2,6,6-tetramethyl-4-piperidyl)thioxantheno[2,1,9dej]isoquinoline 1,3-dione
(BTXINO) and the alkoxy derivative 2-(1-(1′-phenylethoxy)-2,2,6,6-tetramethyl-4-piperidyl)-thioxantheno[2,1,9-dej]isoquinoline-1,3-dione
(BTXINOR). Spectral properties, in solutions and in various polymer matrices such as polystyrene, polymethyl methacrylate,
polyvinyl chloride and polypropylene, were compared with the compound 2-(1-dodecyl)-thioxantheno[2,1,9-dej]isoquinoline-1,3-dione
(BTXID) taken in the present study as a reference compound. By means of the fluorescence decay and in the contrary to three
other probes, BTXINO probe clearly showed a biexponential decay while the three other probes led to monoexponential decay.
Two different singlet excited states with lifetimes of about 0.4 and 5 ns were proposed. They correspond to two dispositions
of the nitroxyl radical chain above and along the fluorescent moiety of the molecule. Such behaviour depends on the surrounding
media. Moreover, an efficient intramolecular quenching of the fluorescence emission was only observed with the short lived
singlet excited state. The ratio BTXID/BTXINO was found equal to about 4 and 9 in solutions and polymer matrices respectively.
Laser flash photolysis indicated that the novel probes as well as the model compound yielded transient absorption with maximum
at 530 nm, corresponding to the triplet states. The intermolecular quenching of such species by molecular oxygen and by free
N-oxyl, such as 1-oxy-2,2,6,6-teramethylpiperidine (TEMPO) and 1-oxy-2,2,6,6-teramethyl-4-hydroxypiperidine (TEMPOL), and
the intramolecular quenching was not efficient. 相似文献
25.
Manuel
Bernard Ghislain Lartigue Guillaume Balarac Vincent Moureau Guillaume Puigt 《国际流体数值方法杂志》2020,92(11):1551-1583
In this article, a new framework to design high-order approximations in the context of node-centered finite volumes on simplicial meshes is proposed. The major novelty of this method is that it relies on very simple and compact differential operators, which is a critical point to achieve good performances in the High-performance computing context. This method is based on deconvolution between nodal and volume-average values, which can be conducted to any order. The interest of the new method is illustrated through three different applications: mesh-to-mesh interpolation, levelset curvature computation, and numerical scheme for convection. Higher order can also be achieved within the present framework by introducing high-rank tensors. Although these tensors feature much symmetries, their manipulation can quickly become an overwhelming task. For this reason and without loss of generality, the present articles are limited to third-order expansion. This method, although tightly connected to the k-exact schemes theory, does not rely on successive corrections: the high-order property is obtained in a single operation, which makes them more attractive in terms of performances. 相似文献
26.
Nicolas Illy Mike Robitzer Rémi Auvergne Sylvain Caillol Ghislain David Bernard Boutevin 《Journal of polymer science. Part A, Polymer chemistry》2014,52(1):39-48
A novel, straightforward and versatile chemical pathway has been studied to functionalize water‐soluble chitosan oligomers. This metal‐free methodology is based on the epoxy‐amine reaction of the allyl glycidyl ether with chitosan, followed by thiol‐ene radical coupling reaction of ω‐functional mercaptans, using 4,4′‐Azobis(4‐cyanovaleric acid) as a free radical initiator. Both reactions were entirely carried out in water. In a preliminary step, chitosan depolymerization was carried out using H2O2 in an acetic medium under 100 W microwave irradiation, optimizing the yield of water‐soluble oligomers. Functionalization by six different thiols bearing alcohol, carboxylic acid, ester, and amino groups was then performed, leading to a range of functional oligochitosans with different grafting efficiencies. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 39–48 相似文献
27.
Abdoul-Fatah Kanta Ghislain Montavon Marie-Pierre Planche Christian Coddet 《Plasma Chemistry and Plasma Processing》2008,28(2):249-262
Modeling the behavior of air plasma spray (APS) process, one of the challenges nowadays is to identify the parameter interdependencies,
correlations and individual effects on coating properties, characteristics and influences on the in-service properties. APS
modeling requires a global approach which considers the relationships between coating characteristics/ in-service properties
and process parameters. Such an approach permits to reduce the development costs. This is why a robust methodology is needed
to study these interrelated effects. Artificial intelligence based on fuzzy logic and artificial neural network concepts offers
the possibility to develop a global approach to predict the coating characteristics so as to reach the required operating
parameters. The model considered coating properties (porosity) and established the relationships with power process parameters
(arc current intensity, total plasma gas flow rate, hydrogen content) on the basis of artificial intelligence rules. Consequently,
the role and the effects of each power process parameter were discriminated. The specific case of the deposition of alumina–titania
(Al2O3–TiO2, 13% by weight) by APS was considered. 相似文献
28.
Ghislain Fourier 《Advances in Mathematics》2009,222(3):1080-1293
We provide combinatorial models for all Kirillov-Reshetikhin crystals of nonexceptional type, which were recently shown to exist. For types , , we rely on a previous construction using the Dynkin diagram automorphism which interchanges nodes 0 and 1. For type we use a Dynkin diagram folding and for types , a similarity construction. We also show that for types and the analog of the Dynkin diagram automorphism exists on the level of crystals. 相似文献
29.
30.
Using a tunable diode-laser spectrometer, we have measured H2-broadening coefficients of PH3 at low temperature (173.2 K) for 27 lines in the QR branch of the ν2 band and in the PP and RP branches of the ν4 band. The recorded lines with J values ranging from 2 to 11 and K from 0 to 9 are located between 1016 and 1093 cm−1. The collisional widths are determined by fitting each spectral line with a Voigt profile and a speed-dependent Rautian profile which provides slightly larger broadening coefficients than the Voigt model. These coefficients have also been calculated on the basis of a semiclassical model of interacting linear molecules by considering an atom-atom Lennard-Jones potential in addition to the weak electrostatic contributions. Except for three QR(J,K) lines, where K = J, the calculated broadening coefficients are in good agreement with the experimental data. By comparing the results obtained at room and low temperatures, the temperature dependence of linewidths has been determined both theoretically and experimentally. 相似文献