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51.
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[structure: see text] Herein we describe an efficient synthesis of cyclophanes comprised of intra-annular nitrogen functional groups through a template-promoted cyclization by ring-closing metathesis (RCM). The synthesis proceeds through condensation of meta-styryl anilines with acenaphthenequinone to form the templates, followed by RCM with Grubb's second-generation catalyst to afford cyclophanes with internal alpha-diimine functionality. Prolonged hydrogenation efficiently removes the template to provide a macrocycle containing the diamine functionality. 相似文献
54.
M. I. Kolybaeva V. I. Salo I. M. Pritula Yu. N. Velikhov A. P. Voronov V. F. Tkachenko V. M. Puzikov 《Crystallography Reports》2004,49(2):266-270
The influence of various technological parameters of crystallization (acidity of growth solutions, crystallization temperature, growth rate, degree of solution purification) on the optical absorption of large KDP single crystals has been studied in the UV range of the spectrum. It is shown that the method of solvent recirculation with the use of the starting material with the microimpurity content not exceeding 5 × 10?5 wt % and solution ultrafiltration under the optimum crystallization conditions (tcr = 80°C, Vcr ~ (0.8–1.6) × 10?6 cm/s, pH 4) enables one to grow KDP single crystals with cross sections up to 300 × 300 mm2 and the transmission in the vicinity of the fundamental absorption edge λ = 200 nm) equal to 86%. 相似文献
55.
56.
A class of one-dimensional parabolic optimal boundary control problems is considered. The discussion includes Neumann, Robin,
and Dirichlet boundary conditions. The reachability of a given target state in final time is discussed under box constraints
on the control. As a mathematical tool, related exponential moment problems are investigated. Moreover, based on a detailed
study of the adjoint state, a technique is presented to find the location and the number of the switching points of optimal
bang-bang controls. Numerical examples illustrate this procedure. 相似文献
57.
Youhua Yang Anna-Britta Hrnfeldt Salo Gronowitz 《Journal of heterocyclic chemistry》1989,26(3):865-868
All three isomeric hitherto unknown thieno[c]isoquinolines have been synthesized in high yields by the Pd(0)-catalyzed coupling of 2-formylbenzeneboronic acid with t-butyl-N-(ortho-halothienyl)carbaniates. When 2-bromoacetanilide, instead of 2-bromoaniline, was coupled with orth-formylarylboronic acids under Pd-catalysis, phenanthridine and thieno[c]quinolines were obtained in improved yields. Total assignments of 1H nmr spectra of thieno[c]isoquinolines and thieno[c]quinolines are reported. Assignments are based on high resolution 300 MHz 1H nmr spectra, two-dimentional 1H-13C chemical shift correlation spectra and one-dimentional INADEQUATE 13C nmr spectroscopy. 相似文献
58.
The finite element based approximation of a quasilinear elliptic equation of non monotone type with Neumann boundary conditions
is studied. Minimal regularity assumptions on the data are imposed. The consideration is restricted to polygonal domains of
dimension two and polyhedral domains of dimension three. Finite elements of degree k ≥ 1 are used to approximate the equation. Error estimates are established in the L
2(Ω) and H
1(Ω) norms for convex and non-convex domains. The issue of uniqueness of a solution to the approximate discrete equation is
also addressed. 相似文献
59.
Carleman estimates and inverse problems for Dirac operators 总被引:1,自引:0,他引:1
We consider limiting Carleman weights for Dirac operators and prove corresponding Carleman estimates. In particular, we show
that limiting Carleman weights for the Laplacian also serve as limiting weights for Dirac operators. As an application we
consider the inverse problem of recovering a Lipschitz continuous magnetic field and electric potential from boundary measurements
for the Pauli Dirac operator.
M. Salo is supported by the Academy of Finland. L. Tzou is supported by the Doctoral Post-Graduate Scholarship from the Natural
Science and Engineering Research Council of Canada. This article was written while L. Tzou was visiting the University of
Helsinki and TKK, whose hospitality is gratefully acknowledged. The authors would like to thank András Vasy and Lauri Ylinen
for useful comments. 相似文献
60.
Francis J. Chung Petri Ola Mikko Salo Leo Tzou 《Annales de l'Institut Henri Poincaré (C) Analyse Non Linéaire》2018,35(3):605-624
In this article we consider an inverse boundary value problem for the time-harmonic Maxwell equations. We show that the electromagnetic material parameters are determined by boundary measurements where part of the boundary data is measured on a possibly very small set. This is an extension of earlier scalar results of Bukhgeim–Uhlmann and Kenig–Sjöstrand–Uhlmann to the Maxwell system. The main contribution is to show that the Carleman estimate approach to scalar partial data inverse problems introduced in those works can be carried over to the Maxwell system. 相似文献