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991.
992.
Abstract –An acoustic method is outlined to detect triplet states formed by radical pair recombination in photosyn-thetic reaction centers. It is based on magnetic field effect on the probability of triplet state formation by recombination. Using a periodically modulated magnetic field in the presence of constant exciting light, a periodic modulation of the triplet state concentration is set in the sample, which is detected through the corresponding modulated heat emission, transduced to acoustic vibration of the gas phase around the sample. This effect is similar to the photoacoustic effect, except that here the light is not modulated. The feasibility of detecting such an effect was proven experimentally, by obtaining a signal from quinone-depleted reaction centers of Rhodobacter sphaeroides. The signal had twice the frequency of the magnetic field modulation; it was proportional to the light intensity and significantly stronger at the lower temperatures (in the investigated range 113–278 K). No signal was obtained from quinone-containing reaction centers, which do not produce triplets. A theoretical outline of the effect and the experimental set-up are described. The "magnitude of the effect was calibrated against ordinary photoacoustic measurements, allowing numerical evaluation of certain parameters of the triplet state ( e.g. triplet energy or yield) with the aid of auxiliary information from the literature. 相似文献
993.
994.
Gerhard Schütte Peter Möller J. Rayford Nix Arnold J. Sierk 《Zeitschrift für Physik A Hadrons and Nuclei》1980,297(4):289-294
We calculate the non-adiabatic excitations of pair states in a BCS formalism for a fissioning236U nucleus. The single-particle spectrum is calculated for a folded-Yukawa potential along a deformation path that is determined classically for one-body dissipation. The resulting microscopic energy dissipation is compared to that due to one- and two-body dissipation. 相似文献
995.
996.
A simple non-resonant sample holder with inclined electrodes is described by means of which transverse sound waves in the GHz range are easily generated by an evaporated piezoelectric layer. Because of its small size it is especially well suited for cryostat applications. 相似文献
997.
Arnold Janssen 《Mathematische Annalen》1980,246(3):233-240
Ohne Zusammenfassung 相似文献
998.
A microscopic relativistic optical model is developed and compared with the empirical optical model at low energies. 相似文献
999.
Magnetic anisotropy and pressure dependence of the order temperature in in the Gd3 (FeTi)29 compound
L. Morellon P. A. Algarabel M. R. Ibarra J. Kamard Z. Arnold L. Pareti F. Albertini A. Paoluzi 《Journal of magnetism and magnetic materials》1995,150(3):L285-L289
In this work we report ac initial magnetic susceptibility under pressure, singular point detection (SPD) and linear thermal expansion measurements in the Gd3(FeTi)29 intermetallic compound. From these measurements we have determined the anisotropy field, the order temperature and its pressure dependence. The thermal exapansion measurement shows an Invar-like anomaly at the order temperature, TC = 520 K, which decreases under increasing pressure with a slope of dTC/dp = 2.7 K/kbar. As the Gd3+ ion is isotropic, no contribution to the anisotropy from the 4f sublattice is and low values of the anisotropy fields have been observed. 相似文献
1000.