Measurements of the brightness temperature and compressibility of a dense silicon plasma formed by powerful shock waves (SWs) passing through a single‐crystal sample have been carried out. Plane SWs ...were created using an explosive technique: the traditional plane acceleration of a steel driver plate made it possible to obtain pressures in silicon up to 133 GPa, and the use of “Mach” cumulative generators realized the pressures up to 510 GPa. The shock Hugoniot of silicon was determined by the impedance matching with α‐quartz as the reference. The intensity of emitted thermal radiation was measured in the infrared range λ ∼ 1.5 μm, where silicon is optically transparent, and in the visible range of the spectrum. A significant (up to five times) understatement of the measured values of the brightness temperature in comparison with the values calculated by the equation of state was found. Taking into account the reflective properties of the SW in silicon does not lead to an agreement with the experiment. The estimates of relaxation processes behind the shock front suggest the presence of a zone of the establishment of ionization equilibrium with a width of ∼10 μm.
A tungsten target has been exposed to pulsed laser ablation in vacuum, gaseous helium, and superfluid (liquid) helium, and ablation products have been studied by means of pyrometric measurements. It ...has been shown that quantitative measurement data for thermal emission characteristics shed light on nanostructure condensation mechanisms in these media. From these data, the cross sections of emitting particles have been calculated. It has been found that submicrometer particles emit mostly in vacuum, whereas emission from nanoparticles has been observed in superfluid helium. The obtained data are substantiated by electron microscopic data.
The peculiarities of the complexation of bovine serum albumin (BSA) and quercetin (Q) are shown in the article. The static mechanism of the formation of BSA-Q conjugates with the predominant effect ...of hydrogen bonds and hydrophobic interaction is established from fluorescence and absorption spectral data of aqueous solutions at different temperatures. The detailed analysis of an interaction of the molecules is performed in a molecular modeling procedure, including docking and molecular dynamics study. The computation results match the experimental outcome.
Experimental estimates of the process of the ejection of particles and the formation of plasma during the shock wave exits on the free surface of the cooper sample studied were carried out. The ...radiation intensity was recorded by a three-channel pulsed pyrometer in an experimental assembly with lateral observation. When the impactor speed was about 5 km/s, a stream of particles and plasma flew from the target surface, the front speed of which reached 12.5 km/s.
In this paper, the authors show the possible way of registration of the microparticles and plasma jets escaping from the inner surface of metal cylindrical liner when the detonation wave reaches it. ...The liner is allocated within experimental setup and is compressed by detonation products. Jets have been registered by Langmuir gauge which connection circuit was developed by the authors. The authors also developed a technique a method for detecting the signal under study. Average particle (about 4 km/s) and plasma (about 7 km/s) jet velocity is estimated by using the developed technique for copper liner compressed by detonation products. The results of this experiment correlate with those for plane setup.
The work is devoted to the study of thermal radiation accompanying the condensation of products of pulsed laser ablation of a tungsten target in vacuum, superfluid and gaseous helium. Pyrometric ...measurements have shown that the radiation characteristics depend on the medium. The obtained data imply that the sources of radiation in vacuum and gas are predominantly submicron particles, while in superfluid helium (He II) they are nanometer particles. These conclusions have been confirmed by electron microscopy data.
The study results of the interaction of bovine serum albumin (BSA) with cerium dioxide CeO
2
nanoparticles in saline solution at different temperatures are presented. The static mechanism of ...fluorescence quenching of the solutions was established. The formation of BSA-CeO
2
conjugates occurs under the predominant van der Waals forces and hydrogen bonds between the components. The established type and values of the interaction energy of the BSA molecule and the nanocerium are in good agreement with the results of the molecular docking modeling. The structure of the BSA - CeO
2
complex was established.
The shock compressibility of single-crystal silicon is experimentally studied in the pressure range of 280 to 510 GPa. Shock waves are created using Mach’s explosive cumulative generators. The ...parameters of shock waves are determined by the impedance matching method, and single-crystal quartz is used as a ref-erence substance. The results agree well with the
ab initio
calculation results and with the data obtained using laser shock waves.
The realization of schemes for measuring rapidly changing resistances in dynamic (explosive) experiments is considered. Practical schemes of two-wire and four-wire resistance measurement techniques ...are presented. The results of the application of the described techniques in an explosive experiment are presented.
In this study, the brightness temperatures of silicon shock-compressed to a pressure of
P
= 68 GPa and the evolution of its temperature during unloading are measured. The measurements were carried ...out in the infrared range Δλ
1
= 1.1–1.7 µm, in which silicon is optically transparent, and in the visible range Δλ
2
= 0.32–1.06 µm. The isentropic unloading of shock-compressed silicon into a vacuum is accompanied by an anomalous increase in the observed temperature.
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