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81.
Audrey Dell Hammerich Abraham Nitzan Mark A. Ratner 《Theoretical chemistry accounts》1994,89(5-6):383-399
Summary We investigate the validity of several common approximations in the analysis of nonadiabatic intramolecular electron transfer rate constants. Utilizing the Fourier representation of the golden rule form, we study the evolution of the vibrational correlation function that represents the density-of-states-weighted Franck-Condon factor. In particular, we test the validity of the perturbation theoretic golden rule form and of the Gaussian wavepacket representation for the vibrational wavefunctions against numerically exact quantum mechanical propagations. Although specific cases are found in which both of these break down, for a wide range of conditions (including anharmonic behavior and frequency changes), both the Gaussian wavepacket representation and the golden rule are excellent approximations. 相似文献
82.
H. -D. Dell M. Doersing J. Fiedler und R. Kamp 《Fresenius' Journal of Analytical Chemistry》1982,311(2):119-122
Zusammenfassung Morocromen-Eigenschaften (Löslichkeit, Extraktion, Stabilität, UV, Fluorescenz, DC) werden beschrieben. Aus biologischem Material (Blut, Organe, Galle, Speichel, Schweiß, Faeces und Urin) ist Morocromen bei pH 8,6 mit Chloroform nahezu quantitativ extrahierbar. Quantitative Bestimmung ist UV-spektroskopisch (330 nm), besser fluorimetrisch durchführbar: direkte Bestimmung bei 330/440 nm als Morocromen oder nach Abbau (4 N H2SO4, 100° C) zum stärker fluorescierenden 7-Amino-Derivat bei 309/483 nm ist bei Mengen von <0,01–5 g/ml nach vorheriger DC möglich.Die untere Nachweisgrenze liegt zwischen 0,02 g/ml (Blut) und 0,008 g/ml (Urin), die Reproduzierbarkeit zwischen 0,7% (Blut) und 3,0–3,6% (Urin). Die Methoden sind für pharmakokinetische Untersuchungen geeignet.
Analysis of morocromen in biological material
Summary Properties of morocromen (solubility, extractability, stability, UV-, fluorescence and TLC-properties) are described. Morocromen can be extracted quantitatively from biological material (blood, organs, bile, saliva, sweat, faeces and urine) with chloroform at pH 8.6. Quantitative determination can be carried out either by UV-spectroscopy (330 nm), or even better by fluorometry: direct determination at 330/440 nm as morocromen or after degradation (4N H2SO4, 100° C) to the more intensely fluorescing 7-amino-derivative (at 309/483 nm) is possible with amounts of <0.01 to 5 g/ml after previous TLC. The lower detection limit is between 0.02 g/ml (blood) and 0.008 g/ml (urine), reproducibility between 0.7% (blood) and 3.0–3.6% (urine). The methods can be used for pharmacokinetic measurements.相似文献
83.
84.
Audrey L. Companion 《Chemical physics letters》1978,56(3):500-502
The diatomics-in-molecules method, with an improved triplet diatomic curve for Li2, is employed in a reexamination of the stability of Li3 and Li4 species. Results are compared to other theoretical and experimental values. 相似文献
85.
J. Henningsen S. A. Trushin T. Møgelberg M. Hammerich 《Applied physics. B, Lasers and optics》1995,61(3):291-299
A tunable source is described, giving extensive coverage of a spectral region around 2000 cm–1. A frequency self-calibration routine allows for the recording of Doppler-limited absorption profiles with an absolute accuracy of better than 10 MHz. The applicability of the source is demonstrated through measurements on the12C16O,12C17O, and12C18O isotopomers. Collision-broadening parameters and line strengths are determined, some of the data showing evidence of motional narrowing. Sensitivity limits are determined for linear absorption measurements as well as for photoacoustic absorption, and the feasibility of monitoring all three isotopomers with ppm sensitivity is demonstrated.Work supported by the Danish Science Research Council under grants no. 11-6866, 11-0116, and 11-0920 相似文献
86.
87.
Transition radiation (TR) has been investigated by using the arithmetic mean and the geometric mean of the pulses from 10 multiwire proportional chambers. The discrimination factor for different kinds of particles has been determined. Also the dependence of the intensity of TR on the Lorentz factor γ has been measured and compared with theoretical calculations. 相似文献
88.
89.
De Giacomo A Dell'Aglio M Casavola A Colonna G De Pascale O Capitelli M 《Analytical and bioanalytical chemistry》2006,385(2):303-311
Double-pulse laser-induced plasma spectroscopy (DP-LIPS) is applied to submerged targets to investigate its feasibility for
elemental analysis. The role of experimental parameters, such as inter-pulse delay and detection time, has been discussed
in terms of the dynamics of the laser-induced bubble produced by the first pulse and its confinement effect on the plasma
produced by the second laser pulse. The analytical performance of this technique applied to targets in a water environment
are discussed. The elemental analysis of submerged copper alloys by DP-LIPS has been compared with conventional (single-pulse)
LIBS in air. Theoretical investigation of the plasma dynamics in water bubbles and open air has been performed. 相似文献
90.
Numerical Algorithms - The Alternating Direction Multipliers Method (ADMM) is a very popular algorithm for computing the solution of convex constrained minimization problems. Such problems are... 相似文献