Picosecond energy transfer of vibrationally hot molecules in solution: Experimental studies and theoretical analysis

1990 ◽  
Vol 93 (6) ◽  
pp. 4094-4101 ◽  
Author(s):  
U. Sukowski ◽  
A. Seilmeier ◽  
T. Elsaesser ◽  
S. F. Fischer
2019 ◽  
Vol 18 (1) ◽  
pp. 163-173
Author(s):  
A. Yu. Botashev ◽  
R. A. Bayramukov

In many industries, the share of small-scale production plants is significant. In these conditions, compared with traditional methods of pressure treatment, pulse pressure treatment methods, one of the varieties of which is gas stamping, are more efficient. However, the known devices of gas stamping provide mainly stamping of thin-walled parts. To expand the technological capabilities of gas stamping, the authors developed a gas stamping device with a piston pressure multiplier, in which heating and deformation of the stamping workpiece is carried out using the energy of combustion of fuel mixtures in the combustion chamber, in the working cylinder and in the cavity of the matrix. This article is devoted to the study of the workflow of this device. Theoretical analysis of the workflow was carried out, and, as a result, a pattern was determined for the variation of the pressure that performs the stamping process in the working cylinder. In particular, it was found that at the final stage of the stamping process, due to the energy of combustion of the fuel mixture, the pressure in the working cylinder increases 1.5...2 times, which allows a significant increase in the thickness of the parts to be stamped. An experimental gas stamping device with a piston pressure multiplier was developed, and experimental studies were carried out. The studies confirmed the main results of the theoretical analysis: the discrepancy between the theoretical and experimental values of the degree of pressure multiplication in the working cylinder does not exceed 11%.


Author(s):  
Minghu Jiang ◽  
Dehai Chen ◽  
Lixin Zhao ◽  
Liying Sun

Developing state-of-the-art and separating principle of deoiling hydrocyclones are introduced. By theoretical analysis, the ways to enhance hydrocyclone’s separation efficiency are described. One way is to inject air into the hydrocyclones so as to combine with oil to form oil-gas compound body, and then increase de-oiling efficiency. By means of injecting air into large cone segment, or fine cone segment of the hydrocyclone, experiments were carried out. It is found that the best injecting part is fine cone segment. Further experimental studies were continued for confirming detail part in fine cone segment, which includes one-third segment and two-thirds segment for the sake of research. Results show that the best air-injecting part is the first one-third segment of fine cone segment. This conclusion would be useful for understanding of air-injected de-oiling hydrocyclone’s separating process, and for its design and applications.


2018 ◽  
Vol 196 ◽  
pp. 04035 ◽  
Author(s):  
Igor Kharchenko ◽  
Alexander Panchenko ◽  
Alexey Kharchenko ◽  
Vyacheslav Alekseev

This paper reports the results of experimental research of the effect of strain-restriction conditions on the structure and properties of sulfoaluminate expanding cementitious materials. Theoretical analysis of the development of pattern formation processes is performed by applying the developed rheological model, illustrating features of the kinetics of structure-forming processes according to the ratio of the potential index of extension with linear, flat and volumetric limitation of deformations of the extension. The results show that rheological model adequately correlates with the results of experimental studies and can be described mathematically. Found that with the volume limitation of deformations arising when mixing crystallographic phases with high density and strength, the pore structure of the cement stone contains mainly gel pores. This is the main prerequisite for obtaining a dense, high-strength and durable structure of cement stone and concrete on its basis.


2012 ◽  
Vol 58 ◽  
pp. 267-270 ◽  
Author(s):  
L. Wiesenfeld ◽  
A. Faure ◽  
F. Lique ◽  
N. Dumouchel ◽  
N. Feautrier ◽  
...  

2020 ◽  
Vol 2 (1) ◽  
pp. 201-215
Author(s):  
R.V. KLYUEV ◽  
◽  
I.I. BOSIKOV ◽  
O.A. GAVRINA ◽  
K.S. KRYSANOV ◽  
...  

The paper presents the results of theoretical analysis and mathematical processing of experimental studies of the insulation state of individual elements of the same type of sections of 0.4 kV electric networks in underground workings conducted at the mining and processing mines at heights of workings up to 1000 m above sea level. The studies were carried out according to a single method in order to identify the effect of highlands on the insulation state of individual elements of 0.4 kV networks. It is recommended to complete scraper winches, fans and other mechanisms of high-altitude mines with organosilicon-insulated engines or with front coatings filled with top coat varnishes similar to excavator engines. A similar situation is noted with the launcher. More than 50 % of all the equipment of high-altitude mines have an active insulation resistance of less than 20 mOhm. A higher asymmetry of the total and active insulation resistance of launchers is noted. It is recommended to use silica gel to reduce air humidity inside the shells of the launcher...


1993 ◽  
Vol 58 (2) ◽  
pp. 213-233 ◽  
Author(s):  
Zuzana Limpouchová ◽  
Karel Procházka ◽  
Vlastimil Fidler ◽  
Jiří Dvořák ◽  
Bohumil Bednář

Theories allowing interpretation of the results of time-resolved polarization spectrofluorimetry in solutions are reviewed and their applicability under various conditions is discussed. For the reorientation of rigid molecules in an isotropic medium, the most frequently employed models are presented, such as rotational diffusion model, the Fokker-Planck-Langevin model, etc. Systems with internal rotation, systems in anisotropic media, systems with a complex electron relaxation and systems with energy transfer are discussed as examples of more complex systems. A special attention is devoted to the polarization fluorimetry of probes bound to/or sorbed at polymer and biopolymer chains. The review focuses on theoretical models of reorientational motion for interpretation of fluorescence anisotropy decays. Experimental studies and computer simulations are discussed only when it is necessary for comparison with theoretical predictions. Complicated models for simultaneous reorientational motion and energy transfer, solvent relaxation, etc., although very important for many applications, exceed the scope of this review and are mentioned only very briefly.


Author(s):  
Д.М. Самосват ◽  
О.П. Чикалова-Лузина ◽  
Г.Г. Зегря

A theoretical analysis of the mechanism of generation of singlet oxygen on the surface of photoexcited nanoporous silicon is presented. It is shown that the nonradiative energy transfer from nanoporous silicon to the oxygen molecule by the Dexter exchange mechanism is the basis for the mechanism of singlet oxygen generation. An analytical expression is obtained and a numerical estimate of the probability of energy transfer from nanoporous silicon to an oxygen molecule is given. It was shown that its numerical value ~ (10^3-10^4) s^{-1} agrees quite well with experiment.


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