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排序方式: 共有274条查询结果,搜索用时 336 毫秒
61.
K. Cruse O. Sauter R. Klockmann und A. Trofimow 《Fresenius' Journal of Analytical Chemistry》1951,132(5):391-398
Ohne Zusammenfassung 相似文献
62.
A quality control procedure for Fused Silica Capillary Column Gas Chromatography/Mass Spectroscopy (FSCC GC/MS) was tested and shown to produce similar response factors at five Spectroscopy (FSCC GC/MS) was tested and shown to produce similar response factors at five laboratories. The average relative standard deviation (RSD) of interlaboratory response factors for fifty three compounds of environmental interest determined at each laboratory at nominal injected weights of 20, 100, and 200 ng was found to be 18.9% for four of the five laboratories which participated in this work. These data demonstrate that similar response factors can be attained in routine GC/MS measurements when adequate quality control is maintained. 相似文献
63.
Zusammenfassung In Fortsetzung früherer Untersuchungen wird die Synthese einer Reihe von neuen unsymmetrisch substituierten Piperazinen beschrieben, die wir für weitere Synthesen benötigten. 相似文献
64.
A. Turgut C. Sauter M. Chirtoc J. F. Henry S. Tavman I. Tavman J. Pelzl 《The European physical journal. Special topics》2008,153(1):349-352
We present a new application of a hot wire sensor for
simultaneous and independent measurement of thermal conductivity k and
diffusivity α of (nano)fluids, based on a hot wire thermal probe with ac
excitation and 3 ω lock-in detection. The theoretical modeling of imaginary
part of the signal yields the k value while the phase yields the α value. Due
to modulated heat flow in cylindrical geometry with a radius comparable to
the thermal diffusion length, the necessary sample quantity is kept very
low, typically 25μl. In the case of relative measurements, the
resolution is 0.1% in k and 0.3% in α. Measurements of water-based
Aerosil 200V nanofluids indicate that ultrasound treatment is more efficient
than high pressure dispersion method in enhancing their thermal parameters. 相似文献
65.
66.
Urs Vögeli Khadijeh Nedaiasl Stefan A. Sauter 《Advances in Computational Mathematics》2018,44(5):1601-1626
In this paper, we present a Galerkin method for Abel-type integral equation with a general class of kernel. Stability and quasi-optimal convergence estimates are derived in fractional-order Sobolev norms. The fully-discrete Galerkin method is defined by employing simple tensor-Gauss quadrature. We develop a corresponding perturbation analysis which allows to keep the number of quadrature points small. Numerical experiments have been performed which illustrate the sharpness of the theoretical estimates and the sensitivity of the solution with respect to some parameters in the equation. 相似文献
67.
68.
Philippe G. Ciarlet Patrick Ciarlet Oana Iosifescu Stefan Sauter Jun Zou 《Comptes Rendus Mathematique》2010,348(9-10):587-592
We consider the pure traction problem and the pure displacement problem of three-dimensional linearized elasticity. We show that, in each case, the intrinsic approach leads to a quadratic minimization problem constrained by Donati-like relations. Using the Babu?ka–Brezzi inf–sup condition, we then show that, in each case, the minimizer of the constrained minimization problem found in an intrinsic approach is the first argument of the saddle-point of an ad hoc Lagrangian, so that the second argument of this saddle-point is the Lagrange multiplier associated with the corresponding constraints. 相似文献
69.
Acid-Catalyzed Reactions of 2-Vinylaniline Derivatives with 1-Benzyl- and 1-Methylpiperidin-4-one: An Elegant Synthesis of New Polycyclic Indole Derivatives The reaction of 2-vinylaniline derivatives with 1-benzylpiperidin-4-one or 1-methylpiperidin-4-one in toluene at temperatures between 115 and 120° with toluene-4-sulfonic acid as catalyst leads in good yields to a new class of polycyclic indole derivatives (Scheme 1, Table 1). The structure of the new diastereoisomerically pure racemic compounds 1–5 is determined by NMR-spectroscopic methods. A reaction mechanism proceeding via cyclization of enamine 9 , leading to a racemic, tricyclic reactive intermediate 10 , and subsequent intramolecular 1,5-dipolar cyclization as key steps in proposed for the formation of octahydropyrido[4′,3′:4]cyclobut[1,2-b]indoles 1–5 . The scope and limitations of the new method are discussed (see Table 2). 相似文献
70.
Ulrich Jordis Fritz Sauter Suhaib M. Siddiqi 《Journal of heterocyclic chemistry》1991,28(8):2045-2047
Starting from trans-4-hydroxy-L-proline, (1R,4S,5R)-endo-N,N-dimethyl-2-azabicyclo[2.2.1]methanamine 1 has been synthesized. The target compound is precursor of antibacterial quinolone carboxylic acids. 相似文献