Determination of the energy measurement accuracy for charged particles by their range in nuclear photoemulsion

Ranges of monochromatic muons in nuclear photoemulsion, produced in the ?? ?? ??? _?? decay, are measured by the coordinate method to determine their energy by the range. The variance of the muon energymeasured by this method ?? _?? = (0.11±0.01) MeV, which corresponds to the accuracy of the determination of the charged particle energy by the range in nuclear emulsion ??3.1%. The developed technique will allow electron energy measurements in the 2??-decay (??3 MeV)with an accuracy of (5?C6)%.     

Synthesis of dichloro derivatives of linear and cyclic permethyloligosilanes and cyclolinear permethylpolysilane-siloxanes and permethylpolyoxysilane based on them

The reactions of dodecamethylcyclohexasilane with chlorides of I, II, IV—VI, and VIII Group metals were studied as a promising approach to the synthesis of functional oligosilanes. When cyclohexasilane reacts with metal chlorides without a solvent at elevated temperatures, the process is intensified and, in some cases, the selectivity of formation of chloro derivatives of linear and cyclic permethyloligosilanes increases. The cyclolinear permethylpolysilane-siloxanes were prepared by heterofunctional polycondensation of the resulting oligosilanes with bifunctional cyclic and linear permethyloligosiloxanes. Cyclolinear permethylpolyoxysilane was synthesized for the first time by the reaction of 1,3-dihydroxycyclohexasilane with 1,3-dichlorohexamethyltrisilane.     

A study of the dimensions of the wake and of the radial distribution of the gas velocity in the wake behind a blunt body moving at hypersonic velocity

We present a method for experimentally studying in a ballistic range the dimensions of the turbulent wake behind a blunt body moving in air at hypersonic speed; included also in our results is the radial distribution of the gas velocity in the wake.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 3, pp. 165–168, May–June, 1976.The author thanks N. N. Baulin, A. S. Mkrtumov, and Yu. N. Urbanovich for their help in carrying out the experimental work.     

Area rule for the wake behind a three-dimensional body

In three-dimensional flows, the local characteristics of the medium in the wake behind a supersonic body at Reynolds numbers Re 5·10⁴ depend in a complicated manner on the coordinates. However, in a number of cases it is important to know only the parameters of the medium averaged over the transverse section of the wake. For example, for the diagnostics of the plasma of the wake behind a body by means of microwave resonators the electron density averaged over the section is used [1]. The chemiluminescent radia tion of the wake is also obtained in an averaged form [2]. It is therefore worthwhile obtaining the average characteristics of the medium without detailed study of the local parameters. In the present paper, a rule is established that makes it possible to use the results obtained for the far viscous wake behind an axisymmetric body in the case of the wake behind a three-dimensional body that is nearly axisymmetric, the flow conditions being similar. The three-dimensional wake is considered to the distances until it degenerates into an axisymmetric wake.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 3, pp. 148–150, May–June, 1980.We thank G. Yu. Stepanov and É. Z. Apshtein for helpful advice in a discussion of the results.     

Thermal and Thermal-Oxidation Stability of Permethylpolysilane-Siloxanes and Permethylpolyoxysilane

Thermal and thermal-oxidation stability of organosilicon copolymers with linear or/and cyclic oligosilane fragments in the backbone was studied by thermal gravimetric analysis in an inert gas and in air. The dependence of the thermal characteristics of polysilane-siloxanes on the number of SiMe₂ units in the oligosilane fragment of copolymers was established.