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701.
On the fast matrix multiplication in the boundary element method by panel clustering 总被引:6,自引:0,他引:6
Summary The boundary element method (BEM) leads to a system of linear equations with a full matrix, while FEM yields sparse matrices. This fact seems to require much computational work for the definition of the matrix, for the solution of the system, and, in particular, for the matrix-vector multiplication, which always occurs as an elementary. In this paper a method for the approximate matrix-vector multiplication is described which requires much less arithmetical work. In addition, the storage requirements are strongly reduced.This paper reports results of a research project supported by the DFG (Schwerpunktprogramm Finite Approximationen in der Strömungsmechanik 相似文献
702.
703.
[reaction: see text] Protection of the amino group of adenine and guanine nucleosides was effected by heating the substrates in 2,5-hexanedione. The resulting 2,5-dimethylpyrrole adducts were stable toward bases but were hydrolyzed with TFA/H(2)O to regenerate the amino function. 相似文献
704.
Applications of the CSB (Common-Sense Builder) system for the logic-oriented and knowledge-assisted simulation of chemical
reaction courses are described. We present the possibility of using the CSB for two ways of reaction simulation, i.e., as
a multi-step process or as single step procedure. Results of the first simulation type are given to predict the course, and
to model reaction mechanism. The second one is capable of complex chemical transformations such as multi-component and cascade
reactions to generate structurally diverse products for combinatorial chemistry. In several experiments performed, we analyze
the capabilities and limitations of the CSB modules and controlling tools for the examination and selective generation of
solutions. 相似文献
705.
Ryszard Czermií nski Krzysztof Kuczera Hanna Rostkowska Maciej J. Nowak Krystyna Szczepaniak 《Journal of Molecular Structure》1986,140(3-4):235-251
Theoretical calculations (on a semi-empirical level) of energy and geometry of the autoassociates of two tautomeric forms of 2-oxo-5X-pyrimidines (X = H, Cl, Br) are presented. On the basis of the calculated energies of autoassociates it is possible to explain the enol—keto tautomeric transition between the gas phase and condensed phases. We propose a double-proton transfer reaction as a possible mechanism for the tautomeric transition.
Infrared absorption spectra of 2-oxo-5X-pyrimidines in the v(NH …) and v(C=O) regions in solid phases and in low-temperature argon matrices are also presented and discussed. Comparison of IR spectra and results of the theoretical calculations with known crystallographic structures of 2-oxo-5X-pyrimidines (X = H, F, Cl) lead to the conclusion that the crystal structure of the 5-bromo derivative should be similar to that of the 5-chloro derivative. 相似文献
706.
The acid soluble compounds of ascites tumor cells after incubation with 32P-orthophosphate were separated by thin-layer chromatography. By using unlabelled deoxyribonucleoside triphosphates it was possible to localize the corresponding radioactive spots. From the radioactivity of the spots and the specific activity of the intracellular orthophosphate the amounts of the deoxyribonucleoside triphosphates could be calculated. 相似文献
707.
V. V. Ammosov S. V. Belikov A. P. Bugorsky S. N. Gurziev A. A. Ivanilov P. V. Ivanov V. I. Konyushko V. M. Korablev V. A. Korotkov A. I. Kurnosenko E. P. Kuznetsov V. V. Makeev A. I. Mukhin A. G. Myagkov A. Yu. Polyarush A. A. Sokolov Yu. M. Sviridov H. J. Grabosch H. H. Kaufmann R. Nahnhauer S. Nowak H. E. Roloff S. Schlenstedt SKAT-Collaboration 《Zeitschrift fur Physik C Particles and Fields》1988,40(4):487-491
In the SKAT neutrino bubble chamber experiment at the Serpukhov accelerator we observe 83 events with electrons and no further lepton in the final state. Comparing the ratio of electron to muon charged current events at energies 3<E v <30 GeV with that expected fromv e -beam background assuming lepton universality we find \(R = (N_{e^ - } /N_{\mu ^ - } )_{\exp } /(N_{e^ - } /N_{\mu ^ - } )_{calc} = 0.98 \pm 0.15\) . Furthermore we compare experimental observations and theoretical expectations for some differential distributions of the electron-neutrino charged current reaction. No significant deviation from lepton universality is found. Looking in the charged current reaction for oscillations of muon to electron type neutrinos we find no effect down to the 90% confidence limits Δm 2 =1.3 eV2 at sin22θ=1 and sin22θ=2.5·10?3 at Δm 2=60 eV2. 相似文献
708.
709.
H. Albrecht H. Ehrlichmann T. Hamacher A. Krüger A. Nau A. Nippe S. Nowak M. Reidenbach M. Sch?fer H. Schr?der et al. 《Zeitschrift fur Physik C Particles and Fields》1992,55(1):25-31
The production ofD
*(2010)+ andJ/ mesons and prompt leptons has been investigated ine
+
e
– interactions at the (1S) resonance energy. The data were collected at the storage ring DORIS II at DESY with the ARGUS detector. We obtain upper limits of BRdir ( (1S)D
*(2010)±+X)<0.019>0.019>x
p
>0.2) and BRdir ((1S)J/+X)<>–3, both at the 90% confidence level. From the prompt lepton analysis, a model dependent limit of BRdir ((1S)Y
c
+X)<0.034>0.034>Y
c
denoting a charm-containing particle) is derived.Supported by the German Bundesministerium für Forschung und Technologie, under contract number 054DO51P 相似文献
710.