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71.
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Yu. A. Ignatov A. A. Klimov S. A. Nikitov 《Journal of Communications Technology and Electronics》2010,55(4):449-456
The anomalous Doppler effect observed during propagation of magnetostatic backward volume waves in a free ferromagnetic film
and magnetostatic surface waves in a ferrite-dielectric-metal structure is investigated. The effect is theoretically substantiated,
and plots of Doppler frequency shift are constructed. The anomalous Doppler effect is qualitatively analyzed with the use
of equifrequency curves. 相似文献
74.
Arabinoxylans (AX) were extracted from Sonalika variety of wheat (whole wheat flour and wheat bran) with barium hydroxide and sodium hydroxide and purified by a combination of alcohol precipitation and glucoamylase digestion. Structural features of purified AX were elucidated by methylation analysis, 13C NMR, FT‐IR, periodate oxidation and optical rotation measurements. The AX showed a backbone of xylose residues with β(1–4) linkages and were branched mainly through O‐3 of xylose residues. Completely branched xylosyl residues were also present. Copyright © 2003 Society of Chemical Industry 相似文献
75.
A. A. El’chaninov A. I. Klimov I. V. Romanchenko V. V. Rostov M. S. Pedos S. N. Rukin K. A. Sharypov V. G. Shpak S. A. Shunailov M. R. Ul’maskulov M. I. Yalandin 《Technical Physics Letters》2013,39(10):910-913
The coherent composition of the wave beams of two relativistic nanosecond backward-wave tubes (BWTs) with an 8-mm range and peak power in each channel of up to 230 MW is implemented. A specific feature of this experiment was power supply of explosive-emission cathodes by split pulses supplied by a completely solid-phase SOS modulator with reduced amplitude scatter. The voltage growth rate was increased compared to previous experiments, which made it possible to transition to the region of weaker magnetic fields ~2 T, which was less than cyclotron resonance field, while retaining stable emission of the electron beams. As a result, a standard deviation of phase scatter between the channels of 0.5 ps was found on the time scale. 相似文献
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Modulation of stability properties of bovine trypsin after in vitro structural changes with a variety of chemical modifiers 总被引:4,自引:0,他引:4
Controlled chemical modification of enzymes, targeting groups not involved
in the active site, can lead to modified catalysts that are intrinsically
more efficient and resistant to heat and denaturing agents. Bovine
pancreatic trypsin was covalently modified up to 75-85% with monomeric
glutaraldehyde (MGA), polymeric glutaraldehyde (PGA), oxidized sucrose and
oxidized sucrose polymers (OSP 70 and OSP 400). Virtually no loss in
activity occurred upon modification. Temperature optima of trypsin shifts
from 45-76 degrees C and T50 from 54-76 degrees C for the best modified
sample made with OSP. The efficiency of the modifiers in stabilization was
ranked in the order: OSP 400-T > OSP 70-T > PGA-T > MGA-T >
Sucrose-T. Half-life of modified enzymes also followed the same trend. Both
stabilization factor and t1/2 decreased with increasing temperatures. The
free energy of activation for inactivation delta(deltaG*) varies from 12-20
kJ/mol and the activation enthalpy delta(deltaH*) of the modified trypsin
by 80-120 kJ/mol indicating stabilization. Inactivation of modified trypsin
by urea is less noticeable. The character of the two-step inactivation
process of trypsin changes with the degree of stabilization in that the
duration of phase I one increased noticeably as stabilization increases.
Native trypsin fluoresces less intensely showing a red shift under the
influence of denaturation. Such a fluorescence change is not so obvious for
the modified enzymes indicating conformational stability acquired by
modification.
相似文献
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MV Zhernovo? SV Lebedev AA Grigoriuk IuA Krasnikov PV Kharitonski? 《Canadian Metallurgical Quarterly》1998,40(7):676-681
The influence of a constant magnetic field (strain 40 kA/m) on retina pigmentary cells of grass frog (Rana temporaria) and grey pigeon (Columba livia) eyes was investigated. Changes in the number and length of melanocytes appendixes were noticed accompanied by formation of thickenings in which melanosomes sized from 0.1 to 0.5 micron are moving. It is established that magnetic properties of eye retina pigmentary cells depend on the presence of Fe3+ in melanin. A theoretical model of paramagnetic receptor has been elaborated, according to which the induction of a magnetic field, formed by melanocyte, makes of the order 100 pT1. This value well compares with the size of magnetic field of a nervous impulse (120 pT1), extending throughout a nervous fibre of the frog sciatic nerve (Wikswo et al., 1980). This allows to suggest a possible unsynaptic way of transferring the information about the perceived magnetic field. 相似文献