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81.
82.
H. Hager 《Analytical and bioanalytical chemistry》1877,16(1):259-259
83.
H. Hager 《Fresenius' Journal of Analytical Chemistry》1872,11(1):203-204
Ohne Zusammenfassung 相似文献
84.
85.
L. Vuaflart E. Truninger A. Stutzer G. Hager J. Kern H. Kappen Ulpiani E. Hene A. van Haaren H. Immendorff und Baessler 《Fresenius' Journal of Analytical Chemistry》1919,58(2):87-96
Ohne Zusammenfassung 相似文献
86.
We propose a class of self-adaptive proximal point methods suitable for degenerate optimization problems where multiple minimizers
may exist, or where the Hessian may be singular at a local minimizer. If the proximal regularization parameter has the form
where η∈[0,2) and β>0 is a constant, we obtain convergence to the set of minimizers that is linear for η=0 and β sufficiently small, superlinear for η∈(0,1), and at least quadratic for η∈[1,2). Two different acceptance criteria for an approximate solution to the proximal problem are analyzed. These criteria
are expressed in terms of the gradient of the proximal function, the gradient of the original function, and the iteration
difference. With either acceptance criterion, the convergence results are analogous to those of the exact iterates. Preliminary
numerical results are presented using some ill-conditioned CUTE test problems.
This material is based upon work supported by the National Science Foundation under Grant Nos. 0203270, 0619080, and 0620286. 相似文献
87.
Given a complex matrix , we consider the decomposition , where is upper triangular and and have orthonormal columns. Special instances of this decomposition include the singular value decomposition (SVD) and the Schur decomposition where is an upper triangular matrix with the eigenvalues of on the diagonal. We show that any diagonal for can be achieved that satisfies Weyl's multiplicative majorization conditions: where is the rank of , is the -th largest singular value of , and is the -th largest (in magnitude) diagonal element of . Given a vector which satisfies Weyl's conditions, we call the decomposition , where is upper triangular with prescribed diagonal , the generalized triangular decomposition (GTD). A direct (nonrecursive) algorithm is developed for computing the GTD. This algorithm starts with the SVD and applies a series of permutations and Givens rotations to obtain the GTD. The numerical stability of the GTD update step is established. The GTD can be used to optimize the power utilization of a communication channel, while taking into account quality of service requirements for subchannels. Another application of the GTD is to inverse eigenvalue problems where the goal is to construct matrices with prescribed eigenvalues and singular values.
88.
Schätz A Rasappan R Hager M Gissibl A Reiser O 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(24):7259-7265
Simple bis(oxazoline) ligands, especially azabis(oxazolines), can promote the copper(II)-catalyzed Michael addition of indoles to benzylidene malonates with up to >99 % ee (ee=enantiomeric excess), provided that the ligand/metal ratio is tuned meticulously with particular regard to the electronic properties of the substrate. Despite a common paradigm followed in many asymmetric catalyses, an excess of chiral ligand is not always beneficial. In fact any excess of ligand has to be avoided to reach excellent enantioselectivities when electron-rich benzylidene malonates are used. On the contrary, malonates carrying an electron-withdrawing group require an excess of ligand for an optimum ee value. A correlation of optical yields versus the sigma(I) values of several para substituents shows a sigmoid trajectory. In the presence of an additive, such as triflate, the significance of the ligand/metal ratio vanishes and very good enantioselectivities are achieved at any rate--no matter whether electron-donating or withdrawing substituents are present. 相似文献
89.
N. G. Basov G. D. Hager A. A. Ionin A. A. Kotkov A. K. Kurnosov J. E. McCord A. P. Napartovich L. V. Seleznev N. G. Turkin 《Optics Communications》2000,180(4-6):285-300
Tunable single-line first-overtone (FO) CO lasing on wavelengths from 2.7 up to 4.2 μm corresponding to overtone vibrational transitions from 13→11 up to 38→36 on 413 ro-vibrational lines was experimentally obtained. A parametric study of energetic and spectral characteristics of the single-line FO CO laser was carried out. Energy distribution over ro-vibrational lines was measured. The maximum specific output energy (SOE) came up to 3 J/l Amagat, with single-line output efficiency being up to 0.6%. For the first time, a multi-quantum theoretical model was used to describe the tunable single-line FO CO laser. This multi-quantum approach demonstrated better agreement between theoretical calculations and observed experimental data for laser output as a function of vibrational quantum numbers. 相似文献
90.
An archimedean ?-group is called epicomplete (or universally σ-complete, or sequentially inextensible) if it is divisible, σ-complete and laterally σ-complete. Various characterizations of such G are known in case the G have weak order units. The “theorem” of the title is a characterization of such G which have no weak order unit; it involves the requirement that G have a certain kind of representation. The “question” of the title is whether every epicomplete G has such a representation. 相似文献