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The dynamics of charge separation states has been numerically simulated in order to calculate the polarization (in the third order of the perturbation theory) and its evolution in a pulsed optical field. Time evolution of the rotational states of the ortho-D2O isomer with a nonzero magnetic momentum and mixed ortho/para-D2O states have been calculated on the basis of the Liouville equation for the density matrix and the Redfield relaxation model for molecular aggregates. Frequencies similar to the known experimental frequencies of the modulation of the kinetics (electron transfer) of the reaction centers special pair in purple bacteria are selected from the set of calculated rotational-resonance frequencies. This semiquantitative coincidence of frequencies (within the experimental error) confirms the previously stated hypothesis, according to which the ortho-H2O (D2O) spin isomer can play a role of mediator during electron transfer in the reaction centers of purple bacteria. 相似文献
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为提高土壤多元素同时检测的效率,采用超级微波消解-电感耦合等离子体发射光谱法测定土壤中钾、钠、钙、镁、铜、铁、锰、锌、磷、硫、硼、砷、镉、铬、铅、钴、镓、锂等18种元素含量。比较了超级微波消解、常规微波消解和电热板消解的处理效果,采用超级微波消解法对样品进行前处理,并优化了消解条件。在最优条件下,各元素的检出限在0.05~20 mg/kg,加标回收率在86.2%~107.5%,RSD在0.1%~3.0%,方法准确度及精密度可以满足多元素同时测定的需求,且该方法具有简单、快速、成本低、用酸量少、重现性好等特点。 相似文献
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设k,n1和n2是3个正整数,G=(V1,V2;E)是一个二分图,使得|V1|=n1,|V2|=n2,其中n1≥2k+1,n2≥2k+1并且n1-n2≤1.如果对任意不相邻的x∈V1和y∈V2,都有d(x)+d(y)≥2k+2,则G包含k个相互独立的圈.以上结果部分地回答了Enomoto提出的关于二分图有独立圈的问题. 相似文献
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A spin mechanism for electron transfer control in the reaction center of purple bacteria in photosynthesis is proposed. Rotation
and conversion of the ortho/para spin isomers of two H2O molecules located near the special pair of the reaction center are treated as the sources of the coherent modulations of
transient kinetics. Modulation of the collective wave function of the reaction center electrons by the total proton spin of
ortho H2O is a key feature allowing the molecule to play the role of a gate controlling the electron transfer. The iron atom in the
reaction center with the gradient magnetic field is treated as a catalyst removing the strict forbiddenness of H2O ortho/para conversion. It is shown that the modulation of the reaction center stimulated emission kinetics observed in the
field of femtosecond pulses coincides with the rotational transitions of ortho/para H2O. Influence of the effect of the electric field (Stark effect) on the level displacement and ortho/para conversion rate is
discussed. 相似文献
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In this paper we study the dispersion relation of thermal non-neutral plasma column by MHD theory. We use the dispersion relation to discuss the stability and dispersive properties in a non-neutral plasma-filled waveguide. The results are in agreement with those of cold non-neutral plasma. 相似文献