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671.
In the present paper, we introduce a new algorithm for the development of efficient numerical methods for the analytical solution of the Löwdin-α radial function. The final results are expressed through the binomial coefficients, which enable fast and accurate calculation of the Löwdin-α radial function. The comparisons of the obtained results with the literature have shown that the presented approach can be used for the fast calculation of multicenter multielectron integrals over Slater-type orbitals (STOs). The efficiency of the algorithm is discussed and its performance with several examples is demonstrated. 相似文献
672.
The Pb5Sb4S11-Pb2SnSb2S6 system was studied by a number of physicochemical methods, and its phase diagram was constructed. It was found that the system
under investigation is a quasi-binary eutectic type section of the SnS-PbS-Sb2S3 ternary system. The coordinates of the eutectic are found to be 33 mol % Pb5Sb4S11 and 750 K. Regions of solid solutions based on Pb5Sb4S11 (6 mol % Pb2SnSb2S6) and Pb2SnSb2S6 (4 mol % Pb5Sb4S11) were determined. 相似文献
673.
Transmembrane charge transfer in photosynthetic reaction centers: some similarities and distinctions
Semenov AY Kurashov VN Mamedov MD 《Journal of photochemistry and photobiology. B, Biology》2011,104(1-2):326-332
This mini review presents a general comparison of structural and functional peculiarities of three types of photosynthetic reaction centers (RCs)--photosystem (PS) II, RC from purple bacteria (bRC) and PS I. The nature and mechanisms of the primary electron transfer reactions, as well as specific features of the charge transfer reactions at the donor and acceptor sides of RCs are considered. Comparison of photosynthetic RCs shows general similarity between the core central parts of all three types, between the acceptor sides of bRC and PS II, and between the donor sides of bRC and PS I. In the latter case, the similarity covers thermodynamic, kinetic and dielectric properties, which determine the resemblance of mechanisms of electrogenic reduction of the photooxidized primary donors. Significant distinctions between the donor and acceptor sides of PS I and PS II are also discussed. The results recently obtained in our laboratory indicate in favor of the following sequence of the primary and secondary electron transfer reactions: in PS II (bRC): Р(680)(Р(870)) → Chl(D1)(В(А)) → Phe(bPhe) → Q(A); and in PS I: Р(700) → А(0А)/A(0B) → Q(A)/Q(B). 相似文献
674.
Shelaev IV Gostev FE Vishnev MI Shkuropatov AY Ptushenko VV Mamedov MD Sarkisov OM Nadtochenko VA Semenov AY Shuvalov VA 《Journal of photochemistry and photobiology. B, Biology》2011,104(1-2):44-50
Low temperature (77-90 K) measurements of absorption spectral changes induced by red light illumination in isolated photosystem II (PSII) reaction centers (RCs, D1/D2/Cyt b559 complex) with different external acceptors and in PSII core complexes have shown that two different electron donors can alternatively function in PSII: chlorophyll (Chl) dimer P(680) absorbing at 684 nm and Chl monomer Chl(D1) absorbing at 674 nm. Under physiological conditions (278 K) transient absorption difference spectroscopy with 20-fs resolution was applied to study primary charge separation in spinach PSII core complexes excited at 710 nm. It was shown that the initial electron transfer reaction takes place with a time constant of ~0.9 ps. This kinetics was ascribed to charge separation between P(680)* and Chl(D1) absorbing at 670 nm accompanied by the formation of the primary charge-separated state P(680)(+)Chl(DI)(-), as indicated by 0.9-ps transient bleaching at 670 nm. The subsequent electron transfer from Chl(D1)(-) occurred within 13-14 ps and was accompanied by relaxation of the 670-nm band, bleaching of the Pheo(D1) Q(x) absorption band at 545 nm, and development of the anion-radical band of Pheo(D1)(-) at 450-460 nm, the latter two attributable to formation of the secondary radical pair P(680)(+)Pheo(D1)(-). The 14-ps relaxation of the 670-nm band was previously assigned to the Chl(D1) absorption in isolated PSII RCs [Shelaev, Gostev, Nadtochenko, Shkuropatov, Zabelin, Mamedov, Semenov, Sarkisov and Shuvalov, Photosynth. Res. 98 (2008) 95-103]. We suggest that the longer wavelength position of P(680) (near 680 nm) as a primary electron donor and the shorter wavelength position of Chl(D1) (near 670 nm) as a primary acceptor within the Q(y) transitions in RC allow an effective competition with an energy transfer and stabilization of separated charges. Although an alternative mechanism of charge separation with Chl(D1)* as the primary electron donor and Pheo(D1) as the primary acceptor cannot be ruled out, the 20-fs excitation at the far-red tail of the PSII core complex absorption spectrum at 710 nm appears to induce a transition to a low-energy state P(680)* with charge-transfer character (probably P(D1)(δ+)P(D2)(δ-)) which results in an effective electron transfer from P(680)* (the primary electron donor) to Chl(D1) as the intermediary acceptor. 相似文献
675.
Bogomolov Yu. V. Alekseev V. V. Levanova O. A. Maiorov A. G. Malakhov V. V. Yazynin S. G. Kataev A. L. Molokoedov V. S. Maksimovskaya A. A. Ruzhickiy V. I. Klenov N. V. Bakurskiy S. V. Kupriyanov M. Yu. Soloviev I. I. Abdullaev N. A. Amiraslanov I. R. Aliev Z. S. Jahangirli Z. A. Sklyadneva I. Yu. Alizade E. G. Aliyeva Y. N. Otrokov M. M. Zverev V. N. Mamedov N. T. Chulkov E. V. 《JETP Letters》2022,116(11):853-854
JETP Letters - An Erratum to this paper has been published: https://doi.org/10.1134/S0021364022380015 相似文献
676.
M. Balasoiu S. G. Barsov D. Bica L. Vekas S. I. Vorob’ev K. I. Gritsaj V. N. Duginov V. A. Zhukov E. N. Komarov V. P. Koptev S. A. Kotov T. N. Mamedov C. Petrescu G. V. Shcherbakov 《JETP Letters》2008,88(3):210-213
A ferrofluid based on Fe3O4 nanoparticles dispersed in heavy water D2O is studied using the μSR method. The experiment has been carried out at temperatures 26–300 K. It is found that the diamagnetic (muon) fraction is formed in the ferrofluid in about the same amount as in D2O, but the muon-spin relaxation rate in the ferrofluid is much higher than in D2O. A significant shift of the muon-spin precession frequency in the ferrofluid is observed. It is shown that the shift of the muon precession frequency as a function of the external magnetic field is described by the Langevin function typical of paramagnetic magnetization. The mean magnetic field in the medium due to magnetic-nanoparticle polarization in an external field is experimentally determined. The nanoparticle sizes are estimated. 相似文献
677.
Effect of diode size and series resistance on barrier height and ideality factor in nearly ideal Au/n type-GaAs micro Schottky contact diodes 下载免费PDF全文
Small high-quality Au/n type-GaAs Schottky barrier diodes (SBDs) with low reverse leakage current are produced using lithography. Their effective barrier heights (BHs) and ideality factors from current-voltage (I-V) characteristics are measured by a Pico ampere meter and home-built I-V instrument. In spite of the identical preparation of the diodes there is a diode-to-diode variation in ideality factor and barrier height parameters. Measurement of topology of a surface of a thin metal film with atomic force microscope (AFM) shows that Au-n type-GaAS SD consists of a set of parallel-connected micro and nanocontacts diodes with sizes approximately in a range of 100-200 nm. Between barrier height and ideality factor there is an inversely proportional dependency. With the diameter of contact increasing from 5 μm up to 200 μm, the barrier height increases from 0.833 up to 0.933 eV and its ideality factor decreases from 1.11 down to 1.006. These dependencies show the reduction of the contribution of the peripheral current with the diameter of contact increasing. We find the effect of series resistance on barrier height and ideality factor. 相似文献
678.
Shemsettin Turkoz Shahin Mamedov Abbas K. Ciftci 《Central European Journal of Physics》2010,8(3):378-385
The motion of colored scalar particles in a constant color magnetic field is considered. The Klein-Gordon equation is solved
in this background and the energy spectrum is quantized by boundary conditions. The unitary transformation diagonalizing this
equation and the states with definite energy are found. 相似文献
679.
Ibrahim Garib Mamedov U. Eichhoff A. M. Maharramov M. R. Bayramov Y. V. Mamedova 《Applied magnetic resonance》2010,38(3):257-269
The formation of hydrogen bonds and molecular dynamics of alkenylphenol derivatives has been investigated in solution using
nuclear magnetic resonance. The results confirm formation of an N···H, O···H-type intramolecular hydrogen bond. The spin–lattice
relaxation times (T
1) and activation energy of molecular dynamics have been investigated confirming the importance of relaxation times as a very
sensitive tool for studying molecular mobility. 相似文献
680.
In this study, the mechanical and electrical degradation properties of the composites of polypropylene (PP)+PP fibers, low-density polyethylene(LDPE)+PP fiber, and PP+fiber glass have been investigated and the validity of Zhourkov's thermofluctuation theory has been shown. 相似文献