薄壁杆系结构的梁元分析模型

本文导出了用于薄壁杆系结构弹性分析的薄壁梁元分析模型，在空间梁元分析模型^[3]的基础上，采用了一种改进的位移模式，考察了薄壁杆件可能发生的拉压，剪切，弯曲，扭转和翘曲等各变形形式以及它们的耦合效应，得出了相应的单元形函数，同时从工程应变的定义出发，采用Taylor级数展开的方法，建立了单元的五阶近似正交变表达式，并建立了相应的薄壁单元刚度方程，从而得出了局部坐标系下单元刚度矩阵的显式，根据本文所导出的薄壁梁元分析模型，编制了相应的结构计算程序，通过算例验证了本文所推导的单元刚度矩阵，同时通过与传统空间梁元计算模型计算结果的比较，阐述了截面翘曲对薄壁杆系结构的影响。     

A Study of the Density Variations of Mesospheric Ozone in the Case of Ionospheric Perturbation by The “Sura” Facility Radiation with Simultaneous Diagnostics of Ionospheric Plasma

Radiophysics and Quantum Electronics - We present the results of microwave observations of atmospheric radiation in the ozone line in the case of ionospheric perturbation by powerful high-frequency...     

A search for extragalactic sources of cosmic rays in the ultra-high energy domain

The arrival directions of ultra-high energy cosmic rays detected with the Yakutsk extensive air shower array are analyzed in comparison with the available data from other giant arrays. A correlation with the coordinates of active galaxy nuclei as hypothesized sources of ultra-high energy cosmic rays is sought for.     

Single polymer molecules in a protein nanopore in the limit of a strong polymer-pore attraction

The capture and release of single poly(ethylene glycol) molecules by the alpha-Hemolysin pore are observed as time-resolved reversible steps in ion conductance. The capture on rate, inferred from the step frequency, decreases monotonically with polymer size. However, the polymer residence time shows a crossover behavior, first increasing and then decreasing with molecular weight. Our interpretation is that, in the case of polymers which are too large to be accommodated within the pore, the out-of-the-pore part of the molecule pulls on the trapped part, thus acting as an entropic spring.     

Application of Empirical Orthogonal Functions Parameterization in the Problem of Retrieval of the Tropospheric Thermal Structure by Radiometric Data

Radiophysics and Quantum Electronics - We describe the mathematical tools of the optimal estimation method for retrieval of tropospheric temperature profiles (0–10 km) from radiometric data...     

Effect of D2O and cryosolvents on the redox properties of bacteriochlorophyll dimer and electron transfer processes in Rhodobacter sphaeroides reaction centers

Effects of environmental changes on the reaction pattern of excitation energy trapping and transformation into the "stable" radical pair P+Q(A)-, have been analyzed in isolated reaction centers of the anoxygenic purple bacterium Rhodobacter sphaeroides. The following results were obtained: (a) replacement of exchangeable protons by deuterons significantly retarded the electron transfer steps of primary charge separation, leading to the radical pair P+I- and of the subsequent reoxidation of I- by the quinone acceptor Q(A) but has virtually no effect on the midpoint potential of P/P+ that was found to be 430+/-20 mV; (b) addition of 70% (v/v) glycerol causes a shift of Em by about 30 mV towards higher values whereas the kinetics of the electron transfer reactions remain almost unaffected; (c) in the presence of the cryoprotectant DMSO, a combined effect arises, i.e. a retardation of the electron transfer kinetics comparable to that induced by H/D exchange and simultaneously an upshift of the Em value to 475+/-20 mV, resembling the action of glycerol. These results are discussed within the framework of effects on the midpoint potential due to the dielectric constant of the medium and changes of the charge distribution in the vicinity of the redox groups and the influence of relaxation processes on electron transfer reactions.     

A Non-Finitely Based Variety of Centre-by-Abelian-by-Nilpotent Groups of Exponent 8

The first example of a non-finitely based variety of centre-by-abelian-by-nilpotentgroups was found in 1995. This example has an infinite exponentbut it can be seen that the method used to construct it alsogives a variety that has an exponent of 128. Later it was provedthat there exists a variety with similar properties but withan exponent of 32. The paper constructs a non-finitely basedvariety of centre-by-abelian-by-nilpotent groups which has anexponent of 8.