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951.
Chemical processing with lasers: Recent developments 总被引:1,自引:0,他引:1
D. Bäuerle 《Applied physics. B, Lasers and optics》1988,46(3):261-270
Chemical processing of materials with lasers is a new and interdisciplinary field with many already realized and potential applications in different areas of technology. This overview summarizes some recent developments in this rapidly expanding field. 相似文献
952.
K. Gäbel Ch. Bergmann E. Fill E. Förster I. Uschmann 《Applied physics. B, Lasers and optics》1993,56(1):3-7
Photo-resonant pumping of X-ray lasers requires close coincidence of a strong emission line with a suitable absorbing transition. We use a high-resolution crystal spectrometer to verify five coincidences, one of which has apparently not yet appeared in published work. All but one of the coincidences are found to lie within one linewidth. With respect to X-ray laser photo-pumping three of the five coincidences seem to be promising candidates. 相似文献
953.
Aminoacidesters and hydroxymethylphosphines form the title compounds, which react as bidentate ligands with Mo (CO)6 to give the cyclic Mo (CO)4 -complexes. 相似文献
954.
Assuming that the conduction electrons of an amorphous metal contribute to the binding, we investigate whether a magnetic field will influence the transition from the amorphous to the crystalline state. Measurements taken on amorphous Bi, Ga and Yb films show no change in the crystallization temperatures within an accuracy of ±0.1 K due to a magnetic field of 18.5 T parallel to the surface of the films.Dedicated to Prof. Dr. W. Buckel on the occasion of his 60th birthday 相似文献
955.
A. B. Sharma S. J. Halme M. Lähteenoja E. J. R. Hubach 《Optical and Quantum Electronics》1983,15(2):95-111
Based on the near-field filtration formulation, the paper identifies and quantifies the most important sources of interlaboratory error in multimode fibre attenuation measurements. Measures are proposed for the reduction of these errors, and it is estimated that a lower bound of about 0.04 dB should be possible under certain assumptions. 相似文献
956.
A high frequency transmission line periodically loaded with varactor diodes is presented to study nonlinear wave propagation.
The nonlinearity and dispersion characteristics are experimentally and theoretically analysed. Experimental results on shock
wave formation and harmonic frequency generation are found to be in good agreement with theoretical predictions. The influence
of dispersion on second-harmonic frequency generation is particularly discussed yielding large values of the efficiency. 相似文献
957.
J. Bräuninger 《Numerische Mathematik》1981,36(4):359-373
Summary This paper presents a modification of the BFGS-method for unconstrained minimization that avoids computation of derivatives. The gradients are approximated by the aid of differences of function values. These approximations are calculated in such a way that a complete convergence proof can be given. The presented algorithm is implementable, no exact line search is required. It is shown that, if the objective function is convex and some usually required conditions hold, the algorithm converges to a solution. If the Hessian matrix of the objective function is positive definite and satisfies a Lipschitz-condition in a neighbourhood of the solution, then the rate of convergence is superlinear. 相似文献
958.
Heiner-Müller-Merbach T. Gal J. Niedereichholz Ch. Schneeweiβ B. Schiemenz W. Törnig D. Hochstädter H. Schellhaas K. Weber G. Reckel W. Dinkelbach W. Rödder 《Mathematical Methods of Operations Research》1973,17(3):158-165
Ohne Zusammenfassung 相似文献
959.
Zusammenfassung Bei den Arzneistoffen Dapson und Ethambutoldihydrochlorid liegen außergewöhnlich komplizierte Polymorphieverhältnisse vor. In beiden Fällen wurden vier Modifikationen nachgewiesen, beiDapson existiert außerdem noch ein Hydrat. Das Dapson-Anhydrat liegt als enantiotrope Mod. III vor, die bei 80° in Mod. II übergeht. Diese Form ist meist bis zu ihrem Schmelzpunkt beständig. Mod. I, die aus der Schmelze kristallisiert, ist ebenfalls mit Mod. II enantiotrop. Außerdem besteht zwischen Mod. I und Mod. III Enantiotropie. Die Umwandlung Mod. IIIMod. II erfolgt spontan und unabhängig von Keimen, so daß der Schmelzpunkt von Mod. III nicht bestimmt werden kann. Bei Mod. IV konnte keine Enantiotropie mit einer anderen Kristallform nachgewiesen werden.
Ethambutoldihydrochlorid weist nur enantiotrope Umwandlungen durch Umklappen ganzer Kristalle in das Gitter der anderen Modifikation auf, so daß nur der Schmelzpunkt der Hochtemperaturform bestimmbar ist. Die Tieftemperaturform besteht aus Mod. II, Mod. IV ist bei Raumtemperatur metastabil, während die instabile Mod. III nur ein ganz schmales Existenzgebiet zwischen ca. 40 und 45° besitzt, da sie sowohl mit Mod. IV als mit Mod. I enantiotrop ist.
On the polymorphism of dapsone and ethambutol dihydrochloride
Summary There are extraordinarily complicated polymorphism conditions in the drugs dapsone and ethambutol chloride. In both cases, four modifications were detected, and in the case of dapsone there exists a hydrate in addition. The dapsone anhydrate is present as enantiotropic Mod. III, which transforms into Mod. II at 80°. This form is mostly stable up to its melting point. Mod. I, which crystallizes from the melt, is likewise enantiotropic with Mod. II. In addition, there is enantiotropy between Mod. I and Mod. III. The transformation of Mod. IIIMod. II takes place continuously and independently from nuclei, so that the melting point of Mod. III cannot be determined. In Mod. IV, no enantiotropy with another crystal form could be detected.Ethambutol dihydrochloride only displays enantiotropic transformations by folding over of entire crystals into the lattice of the other modification, so that only the melting point of the high temperature form can be determined. The low temperature form consists of Mod. II, Mod. IV is metastable at room temperature, whereas the unstable Mod. III only possesses a quite narrow range of existence between about 40 and 45°, since it is enantiotropic both with Mod. IV and with Mod. I.相似文献
960.
Experimental data for chromium(III) complex ions on the spectroscopic properties, photoreactions, and intermolecular energy transfer are analyzed in terms of the primary photophysical and photochemical processes. It is suggested that the lowest excited quartet state,4T2g inO
h
symmetry, is the immediate precursor to photoaquation and that the lowest doublet state,2E, is substitution inert except via the4
T
2g
state reached by back intersystem crossing.
Dedicated to the memory of Professor Hans-Ludwig Schläfer. 相似文献
Zusammenfassung Experimentelle Daten von Chrom-(III)-Komplex-Ionen in bezug auf spektroskopische Eigenschaften, Photoreaktionen und intermolekularen Energieübertragung wurden mit dem Begriffssystem der photophysikalischen und photochemischen Primärprozesse analysiert. Und zwar wird vorgeschlagen, daß der tiefste angeregte Quartettzustand,4 T 2g inO h -Symmetrie, der unmittelbare Vorläufer der Photoaquatisierung ist und daß der tiefste Doublettzustand,2E, inert gegenüber Substitutionen ist, außer über den4 T 2g Zustand, wenn er durch Re-intersystem crossing erreicht wird.
Dedicated to the memory of Professor Hans-Ludwig Schläfer. 相似文献