全文获取类型
收费全文 | 62篇 |
免费 | 0篇 |
国内免费 | 2篇 |
专业分类
化学 | 32篇 |
力学 | 6篇 |
数学 | 19篇 |
物理学 | 7篇 |
出版年
2016年 | 1篇 |
2013年 | 2篇 |
2012年 | 1篇 |
2006年 | 1篇 |
2002年 | 1篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 4篇 |
1996年 | 6篇 |
1995年 | 6篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 3篇 |
1989年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 4篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 3篇 |
排序方式: 共有64条查询结果,搜索用时 0 毫秒
51.
M. Magolu monga Made Henk A. van der Vorst 《Numerical Linear Algebra with Applications》2002,9(1):45-64
Two general parallel incomplete factorization strategies are investigated. The techniques may be interpreted as generalized domain decomposition methods. In contrast to classical domain decomposition methods, adjacent subdomains exchange data during the construction of the incomplete factorization matrix, as well as during each local forward elimination and each local backward elimination involved in the application of the preconditioner. Local renumberings of nodes are combined with suitable global fill‐in strategy in an (successful) attempt to overcome the well‐known trade‐off between high parallelism (locality) and fast convergence (globality). From an algebraic viewpoint, our techniques may be implemented as global renumbering strategies. Theoretical spectral analysis is provided, which displays that the convergence rate weakly depends on the number of subdomains. Numerical results obtained on a 16‐processor SGI Origin 2000 are reported, showing the efficiency of our parallel preconditionings. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
52.
Salvatore Cannistraro Albert van de Vorst Giulio Jori† 《Photochemistry and photobiology》1978,28(2):257-259
Abstract— EPR studies of the porphyrin-sensitized photooxidation of 2, 2, 6,6-tetramethyl-piperidine to the nitroxide demonstrate that all the porphyrins examined are able to generate 1 O2 , although the efficiency of the photoprocess is dependent on the nature of the side chains. Incorporation of metal ions into the porphyrin molecule depresses or even inhibits the formation of 1 O2 . Comparison of these results with previously obtained kinetic data points out that the efficiency of porphyrins as photosensitizes is controlled by the lifetime of their lowest triplet state. 相似文献
53.
J. Decuyper N. Houba-Héin C. M. Calberg-Bacq A. Van De Vorst 《Photochemistry and photobiology》1984,40(1):149-151
Abstract In contrast to previous results obtained with the nitroxide radical detection technique, generation of the specific 1 O2 oxidation product of cholesterol shows that photoexcited acridine orange produces singlet oxygen. 相似文献
54.
Bas van der Vorst E. Matthijs Toose Dirk van den Ende Rob J. J. Jongschaap Jorrit Mellema 《Rheologica Acta》1995,34(3):274-280
A theory analogue to tha of Rouse is given, to describe the rheological behavior of dilute solutions consisting of clusters of crosslinked polymers. The frequency-dependent behavior of the dynamic moduli of these fluids differs substantially from that of the well-known Rouse-like fluid (GG1/2). In our case the storage modulus becomes proportional to 3/2, while the loss modulus is proportional to . The loss modulus dominates the dynamic behavior for frequencies smaller than the largest normal frequency of the clusters. 相似文献
55.
E. L. B. Van De Vorst R. H. B. Fey A. De Kraker D. H. Van Campen 《Nonlinear dynamics》1996,11(3):295-313
This paper deals with the long term behaviour of flexible rotor systems, which are supported by nonlinear bearings. A system consisting of a rotor and a shaft which is supported by one oil journal bearing is investigated numerically. The shaft is modelled using finite elements and reduced using a component mode synthesis method. The bearings are modelled using the finite-length bearing theory. Branches of periodic solutions are calculated for three models of the system with an unbalance at the rotor. Also self-excited oscillations are calculated for the three models if no mass unbalance is present. The results show that a mass unbalance can stabilize rotor oscillations. 相似文献
56.
Abstract— Photoacoustic spectroscopy has been used to observe a qualitative depth profile in vitro in mouse skin. Because the photoacoustic response is a vector quantity, it can be used to qualitatively determine the depth of a chromophore in skin. The spectrum of an induced layer of β-carotene in albino mouse skin was separated from the spectrum of hemoglobin. Dyes were then used to determine more precisely the position of the β-carotene in the epidermis. The spectrum of melanin was also separated from that of the underlying hemoglobin in pigmented mouse skin. 相似文献
57.
Salvatore Cannistraro † Giulio Jori‡ Albert Van de Vorst 《Photochemistry and photobiology》1978,27(5):517-521
Abstract— The low spin hemin derivative di-cyan-hemin can sensitize the photooxidation of amino acids. The efficiency of this dye as a photosensitizer is generally lower than that of other porphyrins such as hematoporphyrin in aqueous solution, but it is significantly enhanced by addition of ethanol. On the basis of the identified photooxidation end-products of some amino acids, photooxidation kinetic data and EPR measurements, it appears that methionine is quantitatively converted to methionine sulfoxide by a pure Type II (singlet oxygen) mechanism, whereas in the case of cysteine and tryptophan a mixed Type ILType II mechanism is probably operative. 相似文献
58.
The polarization energies of AB compounds, with A a monovalent or divalent cation with an (ns)2-lone pair and B an anion with a noble gas electronic configuration, have been calculated to investigate whether the stereochemical activity of the (ns)2-ion can be understood in an ionic picture. Computations have been performed applying the computer program EWALD. Formal ionic charges and partly estimated polarizabilities have been used. The polarization energy is shown to be predominantly due to cation polarization and may constitute an appreciable fraction of the total lattice energy. Hence, it can play a crucial role in the formation of structures, in which the (ns)2-ion is in a noncentrosymmetrical environment. 相似文献
59.
PHOTOTOXIC POTENTIALITIES OF TARTRAZINE: SCREENING TESTS 总被引:1,自引:0,他引:1
M. P. Merville J. Decuyper M. Lopez J. Piette A. Van De Vorst 《Photochemistry and photobiology》1984,40(2):221-226
Abstract Tartrazine (TRT) a cosmetics, food and drug additive, was tested with respect to phototoxic potentialities. Although, using the cholesterol technique, TRT did not appear to produce any 1 O2 upon visible light irradiation, the EPR spin trapping experiments with 5,5-dimethyl-1-pyrroline-N-oxide, as spin trap, were in favour of activated oxygen species (O2 ˙ , OH˙ ) and hydrated electron production by photoexcited TRT.
Irradiation of TRT with complementary biological systems (nucleic acids, bacteria, biological membranes) showed that few of them can be damaged by this photosensitizer. Tartrazine could induce a weak deoxyribose degradation but did not produce any DNA strand breaks on isolated φXRFI DNA. Tartrazine was detected as mutagen in the Salmonella microsome (Ames) assay, only in conjunction with visible light. In the presence of photoexcited TRT, erythrocyte membranes were damaged by covalently cross-linking proteins.
The tests developed here seem thus to be suitable for detecting any unwanted phototoxic activity associated with potential photosensitizers. 相似文献
Irradiation of TRT with complementary biological systems (nucleic acids, bacteria, biological membranes) showed that few of them can be damaged by this photosensitizer. Tartrazine could induce a weak deoxyribose degradation but did not produce any DNA strand breaks on isolated φXRFI DNA. Tartrazine was detected as mutagen in the Salmonella microsome (Ames) assay, only in conjunction with visible light. In the presence of photoexcited TRT, erythrocyte membranes were damaged by covalently cross-linking proteins.
The tests developed here seem thus to be suitable for detecting any unwanted phototoxic activity associated with potential photosensitizers. 相似文献
60.
D. Vanhoenacker A. Vander Vorst 《International Journal of Infrared and Millimeter Waves》1990,11(4):519-532
The paper describes a deterministic model for the effects of atmospheric turbulences on satellite-earth links from 1 to 100 GHz. Turbulent cells are considered as dielectric volumes crossing the Fresnel's zones of the link. The transmission coefficients are calculated for point receivers as well as for actual aperture antennas. The model yields a transfer function submitted to the influence of the equivalent dielectric constant, the thickness, size, and geometry of the cells, the size of the antenna, and the operating frequency. The resulting group delay is also evaluated, as well as the impulse and step-responses. 相似文献