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961.
962.
Lars Vretare 《Mathematische Zeitschrift》1985,188(3):419-425
963.
964.
965.
We describe a new algorithm to compute the eigenvalues of singular Sturm-Liouville problems with separated self-adjoint boundary conditions for both the limit-circle nonoscillatory and oscillatory cases. Also described is a numerical code implementing this algorithm and how it compares with SLEIGN. The latter is the only effective general purpose software available for the computation of the eigenvalues of singular Sturm-Liouville problems. 相似文献
966.
967.
Lars Eldén 《BIT Numerical Mathematics》1977,17(2):134-145
Two regularization methods for ill-conditioned least squares problems are studied from the point of view of numerical efficiency. The regularization methods are formulated as quadratically constrained least squares problems, and it is shown that if they are transformed into a certain standard form, very efficient algorithms can be used for their solution. New algorithms are given, both for the transformation and for the regularization methods in standard form. A comparison to previous algorithms is made and it is shown that the overall efficiency (in terms of the number of arithmetic operations) of the new algorithms is better. 相似文献
968.
Angular distributions of transitions to 29 states in46Ti between 7.6 and 11.0 MeV excitation energy from the45Sc (3He,d) reaction at 15 MeV have been compared with DWBA predictions. The results support previously suggestedT=2 states in46Ti. 相似文献
969.
Summary.
Let the Cholesky decomposition of be ,
where is upper triangular. The Cholesky block downdating
problem is to determine
such that ,
where is a block of rows from the data matrix .
We analyze the sensitivity of this block downdating problem of
the Cholesky factorization.
A measure of conditioning for the Cholesky block downdating
is presented and compared to the single row downdating case.
Received September 15, 1993 相似文献
970.
Jurva U Wikström HV Weidolf L Bruins AP 《Rapid communications in mass spectrometry : RCM》2003,17(8):800-810
The extent to which electrochemistry on-line with electrospray mass spectrometry can be used to mimic cytochrome P450 catalyzed oxidations has been investigated. Comparisons on the mechanistic level have been made for most reactions in an effort to explain why certain reactions can, and some cannot, be mimicked by electrochemical oxidations. The EC/MS/MS system used successfully mimics in cases where the P450 catalyzed reactions are supposed to proceed via a mechanism initiated by a one-electron oxidation, such as N-dealkylation, S-oxidation, P-oxidation, alcohol oxidation and dehydrogenation. The P450 catalyzed reactions initiated via direct hydrogen atom abstraction, such as O-dealkylation and hydroxylation of unsubstituted aromatic rings, generally had a too high oxidation potential to be electrochemically oxidized below the oxidation potential limit of water, and were not mimicked by the EC/MS/MS system. Even though the EC/MS/MS system is not able to mimic all oxidations performed by cytochrome P450, valuable information can be obtained concerning the sensitivity of the substrate towards oxidation and in which position of the molecule oxidations are likely to take place. For small-scale electrochemical synthesis of metabolites, starting from the drug, the EC/MS/MS system should be very useful for quick optimization of the electrochemical conditions. The simplicity of the system, and the ease and speed with which it can be applied to a large number of compounds, make it a useful tool in drug metabolism research. 相似文献