排序方式: 共有44条查询结果,搜索用时 15 毫秒
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Dye ST Annis J Becker-Szendy R Bratton CB Casper D Claus R Crouch M Errede S Gajewski W Goldhaber M Haines TJ Jones TW Kielczewska D Kropp WR Learned JG LoSecco JM McGrew C Matthews J Mudan MS Price LR Reines F Schultz J Seidel S Sinclair D Sobel HW Stone JL Sulak LR Svoboda R Thornton G van der Velde JC 《Physical review letters》1989,62(18):2069-2072
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JC Wolff S Monte N Haskins D Bell 《Rapid communications in mass spectrometry : RCM》1999,13(18):1797-1802
Structural analysis of minor components in mixtures is a vital requirement in the development of any pharmaceutical compound. Mass spectrometry is uniquely able to give this kind of information on the trace amounts of material present as minor impurities in a drug substance. In this study we show that a combination of mass spectrometric analysers with different characteristics is an even more powerful approach with a higher chance of establishing a potential structure. In particular the advent of analysers capable of accurate mass measurement on small amounts of material has enabled structures to be proposed in situations where previously no real conclusions could be made. Copyright 1999 John Wiley & Sons, Ltd. 相似文献
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In this paper the exact solution of the non-symmetric matrixRiccati equation with analytic coefficients is approximatedby a rational matrix function with a prefixed accuracy. Thisrational matrix function is locally defined as the exact solutionof a Riccati problem with matrix polynomial coefficients obtainedby truncation of the Taylor expansions of the matrix coefficientsof the original problem. 相似文献
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This paper presents a numerical method for solving the two‐dimensional unsteady incompressible Navier–Stokes equations in a vorticity–velocity formulation. The method is applicable for simulating the nonlinear wave interaction in a two‐dimensional boundary layer flow. It is based on combined compact difference schemes of up to 12th order for discretization of the spatial derivatives on equidistant grids and a fourth‐order five‐ to six‐alternating‐stage Runge–Kutta method for temporal integration. The spatial and temporal schemes are optimized together for the first derivative in a downstream direction to achieve a better spectral resolution. In this method, the dispersion and dissipation errors have been minimized to simulate physical waves accurately. At the same time, the schemes can efficiently suppress numerical grid‐mesh oscillations. The results of test calculations on coarse grids are in good agreement with the linear stability theory and comparable with other works. The accuracy and the efficiency of the current code indicate its potential to be extended to three‐dimensional cases in which full boundary layer transition happens. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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A. Bürger M. Stanoiu F. Azaiez Zs. Dombrádi A. Algora A. Al-Khatib B. Bastin G. Benzoni R. Borcea Ch. Bourgeois P. Bringel E. Clément J.-C. Dalouzy Z. Dlouhý A. Drouart C. Engelhardt S. Franchoo Zs. Fülöp A. Görgen S. Grévy H. Hübel F. Ibrahim W. Korten J. Mrázek A. Navin F. Rotaru P. Roussel-Chomaz M.-G. Saint-Laurent G. Sletten D. Sohler O. Sorlin Ch. Theisen C. Timis D. Verney S. Williams 《The European physical journal. Special topics》2007,150(1):89-91
An experiment was performed to extend the knowledge of excited
states in neutron-deficient Ca isotopes.
In particular, the first excited state in 36Ca was searched for
to obtain information on the isospin dependence of the
nucleon-nucleon interaction near the proton drip line from a
comparison with its stable mirror nucleus, 36S.
The 36Ca ions were produced using a two-step fragmentation
technique with a 37Ca secondary beam, and in-beam γ-rays
were measured.
First results are the energy of the first 2+ state in 36Ca,
E(2+)=3036(11) keV, and the cross section for the reaction
37Ca → 36Ca at 61.A MeV.
In addition, the de-excitaion of the first 2+ state in 28S
has been observed. 相似文献
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Terence Davis Matthew C Dix Michal J Rokicki Amy JC Brook Caroline S Widdowson David Kipling Mark C Bagley 《Chemistry Central journal》2011,5(1):1-5
To develop more potent small molecules with enhanced free radical scavenger properties, a series of N-substituted isatin derivatives was synthesized, and the cytoprotective effect on the apoptosis of PC12 cells induced by H2O2 was screened. All these compounds were found to be active, and N-ethyl isatin was found with the most potent activity of 69.7% protective effect on PC12 cells. Structure-activity relationship analyses showed the bioactivity of N-alkyl isatins decline as the increasing of the chain of the alkyl group, furthermore odd-even effect was found in the activity, which is interesting for further investigation. 相似文献
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The relative rates of H-transfer between partners in ion-neutral complexes were compared with those in intramolecular rearrangements using results of first differential photoionization mass spectrometry measurements. Complex-mediated H-transfers are inferred to have rates of the same order as those for intramolecular hydrogen rearrangements, suggesting a similar range of motion of the reactive sites in both types of reactions. It is also concluded that at their fastest H-transfers take place between the partners in ion-neutral complexes within at most the time of several rotations of the partners in the complexes. Copyright 1999 John Wiley & Sons, Ltd. 相似文献