The high-speed electronic computer of the U.S.S.R. Academy of Sciences (BESM)

1956 ◽  
Vol 103 (2S) ◽  
pp. 280-286
Author(s):  
V.A. Melnikov
2021 ◽  
Author(s):  
◽  
John Patrick Macarthur Bailey

<p>This thesis, the first thesis in theoretical chemistry submitted for the degree of Master of Science at Victoria University of Wellington, has been designed to illustrate two alternative approaches to theoretical studies. The first five chapters illustrate the modern use of operator methods; the last two are concerned mainly with molecular orbital calculations for large organic molecules, using a giant high speed electronic computer. I am deeply indebted to Mr Keith Morris, of the Applied Mathematics Division, Department of Scientific and Industrial Research, for his generous and highly competent help in writing computing programs, and operating computers, at all odd hours of the day and night, for the calculations in this thesis. I would also like to thank Dr R.M. Golding, for useful discussions, and the Director, Applied Mathematics Division, Department of Scientific and Industrial Research, for making computing facilities available.</p>


A method is described whereby an electronic computer, the EDSAC, may be used to select a set, or sets, of signs for the coefficients F (h) of a Fourier series, such that the Fourier series, satisfies a certain condition. This condition is expressed as X ≡ Ʃ h Ʃ h ' P (h,h') S (h) S (h') S (h+h')≽ X 0 , where S (h) denotes the sign of F (h) and P (h, h') is a weighting factor related to the probability that S (h) S (h') = S (h+h'). In certain circumstances the determination of a crystal structure which is beyond the range of other direct methods is possible by this procedure.


This paper discusses some possible procedures for crystal structure determination using the X criterion developed in the preceding paper of the series. In that paper it was shown that, under favourable circumstances, the signs of the largest terms in the Fourier series representa­tion of ρ , the electron density in the unit cell, can be determined directly. The magnitudes of these terms can be found by experiment. In less favourable cases the correct set of signs, to a high degree of probability, lies among several hundred possible sets which can be determined by the processes described. A new criterion is proposed for selection of a lesser number, say a dozen, ‘most probable’ sets of signs. These latter sets can be tested by inspection of the corre­sponding contour maps of ρ . The new criterion has been successfully used in determining the unknown structure of nitroguanidine. Techniques for the selection of most probable sets and also for evaluation of ρ at suitable points in space using an electronic computer, the EDSAC, are described.


1958 ◽  
Vol 28 (6) ◽  
pp. 1126-1129 ◽  
Author(s):  
Donald A. Flanders ◽  
Hugo Fricke

2019 ◽  
Vol 213 ◽  
pp. 02036
Author(s):  
Alexander Kandaurov ◽  
Daniil Sergeev ◽  
Yuliya Troitskaya ◽  
Olga Ermakova

The paper presents the results of investigations of the mechanisms of spray of droplets generation within wind wave interaction obtained under laboratory conditions on the High-speed Wind-Wave Flume of the Institute of Applied Physics of the Russian Academy of Sciences. For the research, a multi-angle high-speed video system used together shadow method, including underwater illumination. The results allowed for the classification of mechanismsleading to the formation of droplets. Three main types of phenomena responsible for the generation of the spume droplets near the wave crest were specified: breakage of liquid ligaments, bursting of large submerged bubbles, and bag breakup. The last and less known mechanism claims to be dominant for high wind speeds and it was described in detail.


2021 ◽  
Vol 31 (2) ◽  
pp. 23-34
Author(s):  
V. G. Krivenko ◽  
◽  
Yu. L. Khodasevich ◽  
S. N. Pantuz ◽  
V. I. Emalyanenko ◽  
...  

An experimental multifunctional high speed registration spectrofluorimeter SFL-S has been developed at the Institute for Biological Instrumentation of the Russian Academy of Sciences. The spectroflu-orimeter is designed to measure excitation and emission spectra of solutions and suspensions of bio-logical molecules and cells in the ultraviolet, visible, and near infrared spectral regions in the course of fundamental and applied research in the field of physicochemical biology, biophysics, biochemistry, and medicine. Features of the instrument are: the possibility of high-speed registration of spectra by means of multichannel system (32 channels, more than 20 spectra per second); the ability to control the change of the temperature of the solution in the measuring cell according to a given algorithm (0 to 100 °C); the possibility of microtitration of the solution in the measuring cell using an automatic microtitrator.


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