Application of Ellipsometry to Control the Plasmachemical Synthesis of Thin TiONx Layers

Ellipsometry is often used to determine the characteristics of films. Ellipsometric studies may turn out to be ineffective because several solutions correspond to the same polarization angles. It is demonstrated that the ambiguity is not due to the physical limitations of the method but it has a purely mathematical character. So, additional information about the film is necessary to determine the absolute values of refractive index, attenuation, and thickness

QCM-based rapid analysis of DNA

We demonstrated that it is possible to break apart double-stranded DNA using a thickness shear mode resonator. This procedure measures the force of bond rupture. The measured rupture forces were in the range of 10–40 pN. The procedure was tested experimentally with model complementary and non-complementary oligonucleotides. In the case of the DNA mismatch we observed a signal at a driving voltage of 0.8 V (corresponding to a shear force of 11 pN), while in the case of complementarity the signal at the voltage of 3 V (36 pN) appeared. This procedure may be the ground for the development of new types of biosensors measuring the force of affine interactions (probe/biomolecular target) on the surface of the sensor element

Distribution of the stable isotopes (δ

Results of the study of the stable isotopes (δ18O, δD and δ13C) distribution in natural waters of the Baydar valley (southwestern part of the Crimean Peninsula) are presented. The study region holds fresh and ultra-fresh waters of predominantly bicarbonate calcium composition with TDS varying from 194 to 1137 mg/dm3. The research results revealed that all of the studied waters are of atmospheric origin that lie either along the global (GMWL) or local (LMWL) meteoric water lines. The established variations are: from -9.5 to -5.6‰ for δ18O values in waters with δD values varying from -64.0 to -40.0‰. The source for bicarbonate ion enriched in δ13C in natural waters of the Bauydar valley are carbonate sedimentary rocks, atmospheric carbon dioxide and organic compounds. Surface waters have heavier isotopic composition δ13C (-9.2 – -7.0‰) because of the atmospheric CO2. Artesian waters are differentiated by lighter δ13C (-12.8 – -10.7‰) due to the interactions between carbonate rocks and the dispersed organic matter. Water sources (springs, wells) are characterized by the widest variations of δ13C (-6.9 – -15.5‰) due to the presence of the atmospheric CO2 and intense processes of biochemical decomposition of organic compounds in the soil layer

TOXIC ELEMENTS IN GROUNDWATER IN THE NORTHERN REGIONS OF THE OB-ZAYSAN FOLDED REGION

Link for citation: Maksimova A.A., Chernykh A.V., Novikov D.A., Dultsev F.F., Derkachev A.S., Sukhorukova  A.F., Nikitenkov  A.N., Khvachshevskaya  A.A. Toxic elements in groundwater in the northern regions of the Ob-Zaysan folded region. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 5, рр.17-26. In Rus. The relevance of this research lies in the need to study the distribution of elements of the first hazard class, uranium and thorium in the groundwater of the Ob-Zaisan folded area. Objective: to establish the characteristics of the hydrogeochemical background and to study the distribution of highly toxic chemical elements in the waters of the drinking water supply of the population. Methods. Rapidly changing parameters were determined using a field hydrogeochemical laboratory and field equipment Hanna HI98195 – a multi-parameter pH/ORP/conductivity meter, Hanna HI98198 – an oximeter. The measurement of radon activity in groundwater was carried out using the Alfarad plus complex. Laboratory studies of the chemical composition by means of titration, ion chromatography, mass spectrometry with inductively coupled plasma were carried out at the Research Laboratory of Hydrogeochemistry at the School of Earth Sciences and Engineering of the Tomsk Polytechnic University. The assessment of the toxicological characteristics of waters was carried out using the current regulatory documents: SanPiN 2.1.3684-21, SS R 58573-2019 and the recommendations of the World Health Organization. The hydrogeochemical background was calculated using the Statistica 8.0 software package (StatSoft. Inc.). To determine the extent of element concentrating in natural waters, the coefficients of concentration  and water migration (according to A.I. Perelman)  were calculated. Cumulative curves are calculated by the formula: Pc=Ri/(N+1). Results. The studied waters are HCO3 Mg-Ca and HCO3 Na-Mg-Ca composition with total mineralization varying from 203 to 1568 mg/dm3. The geochemical parameters of the environment are both reducing and oxidizing with Eh –331,6 – +438,5 mV, pH 6,6–8,3 with the content of O2disol. 0,29–10,72 mg/dm3. The authors revealed relatively high concentrations of Ti – up to 0,04 mg/dm3, V – up to 0,03 mg/dm3, Fe – up to 93,9 mg/dm3, Zn – up to 0,38 mg/dm3, As – up to 0,27 mg/dm3, Zr – up to 0,018 mg/dm3, Sb – up to 0,016 mg/dm3, Ba – up to 0,51 mg/dm3, W – up to 0,005 mg/dm3, Hg – up to 0,0002 mg/dm3, Pb – up to 0,057 mg/dm3, U – up to 0,34 mg/dm3, which is probably related to the composition of host rocks and the spread of industrial enterprises developed in the study area. The elements of the first hazard class, as well as uranium and thorium, were studied in the work. It was found that 20 % of the studied samples were higher than the background value for beryllium, as well as for thallium and arsenic, 26 % – for thorium, and 19 % – for uranium