Experimental investigation of the effect of longitudinal riblets on the friction drag of a flat plate

The results of a gravimetric investigation of the effect of longitudinal riblets on the friction drag of a flat plate are presented. The experiments were carried out with both natural and artificially thickened developed turbulent boundary layers in a zero-gradient flow.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 2, pp. 140–145, March–April, 1987.The authors wish to thank V. V. Mikhailov for his valuable assistance.     

Iodine-starch clathrate complexes under the impact of a low-frequency acoustic field

The results from research on the kinetics of destruction of clathrate complexes (amyloidine, amylopectoiodine and iodinol) in low-frequency acoustic waves from 5 to 25 Hz are presented. Features of the transfer of energy from low-frequency acoustic oscillations are determined. The ability of systems containing biologically active clathrate structures to interact in resonance with external acoustic stimuli according to the energy state of the active part of iodine-containing compexes is confirmed. In the first approximation, such compounds can be regarded as model biochemical systems.     

Mathematical modeling of matter distribution in a circular cell ensemble

In this paper, a mathematical model describing substance transport in a circular cell ensemble is considered. The model is represented by an autonomous system of equations. With a parameter continuation model, it is shown that the stationary solutions may have various symmetry types represented by closed curves. The periodic solutions have the same property, where the components differ from each other by a simple shift.     

α,α-Difluorination of mononitrocompounds with elemental fluorine

The difluorination of fluorodinitromethane, 2-fiuoro-2-nitroethanol, and ethyl 2-fluoro-2-nitroacetate has been carried out to yield difluoronitromethane, 2,2-difiuoro-2-nitroethanol, and ethyl 2,2-difluoro-2-nitroacetate.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1495–1497, August, 1993.     

Application of laser induced saturation of molecular fluorescence for lifetime measurements

A technique for the determination of fluorescence lifetimes based on the laser induced saturation of molecular fluorescence is described. It allows lifetime measurements using exciting laser pulses longer than the lifetime under determination. The range of applicability of the technique is discussed and an experimental verification is carried out.     

Influence of condensation nuclei on the optical properties of atmospheric aqueous aerosol

The paper presents the results of investigations on the indicatrices and angular dependence of the degree of polarization of scattered radiation by fog in the visible and near-infrared regions of the spectrum. By judicious comparison of the measured results with calculated data a law was established for the influence of condensation nuclei on the optical properties of atmospheric aqueous aerosol.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 128–131, January, 1976.     

Properties of Spreaded Collagen I Monolayers on the Surface of Aqueous tert-Butanol and n-Hexanol Solutions

Properties of the monolayers of collagen isolated from the sclera of pig's eye are studied at the air–water interface with increasing tert-butanol or n-hexanol concentrations in a subphase. In the case of aqueous n-hexanol solutions, its adsorption on the subphase surface results in the formation of mixed monolayer whose properties depend on n-hexanol concentration in the subphase and the ratio between the number of alcohol and collagen molecules in the monolayer. At higher n-hexanol surface concentration, the phase separation of the monolayer into the domains of the condensed phase of alcohol and fibrous collagen occurs. A decrease in water activity in the presence of tert-butanol leads to a drastic reduction of collagen surface activity. This effect can be explained by both the constrained collagen spreading on the surface of tert-BuOH solutions and adsorption of alcohol molecules on collagen resulting in macromolecule hydrophilization. Alcohol critical concentrations are disclosed above which collagen monolayers are not formed.     

一种EGA—MS系统的标定方法

ＣａＣ２Ｏ４真空热分解中，第一阶段生成的ＣＯ中４７％歧化成ＣＯ２和Ｃ；第二阶段生成的ＣＯ与第一阶段生成的Ｃ发生气化反应，发生反应的比例随样品量增加而增大。用ＣａＣＯ３标定ＣＯ后再用ＣａＣ２Ｏ４标定ＣＯ可以排除这些干扰。本文提出了一个对任意气体标定的方法。