Modifications of EHPDB Physical Properties through Doping with Fe2O3 Nanoparticles (Part II)

The aim of our study was to analyze the influence of various concentrations of γ-Fe2O3 nanoparticles on the physical properties of the liquid crystalline ferroelectric SmC* phase, as well as to check the effect of introducing nanoparticles in the LC matrix on their properties in the prepared five nanocomposites. UV-vis spectroscopy showed that the admixture reduced the absorption of nanocomposites in the UV range, additional absorption bands appeared, and all nanocomposites were transparent in the range of 500–850 nm. The molecular dynamics in particular phases of the nanocomposites were investigated by the dielectric spectroscopy method, and it was found that nanoparticles caused a significant increase in the dielectric constant at low frequencies, a strong modification of the dielectric processes in the SmC* phase, and the emergence of new relaxation processes for the highest dopant concentrations. SQUID magnetometry allowed us to determine the magnetic nature of the nanoparticles used, and to show that the blocked state of nanoparticles was preserved in nanocomposites (hysteresis loops were also registered in the ferroelectric SmC* phase). The dependence of the coercive field on the admixture concentration and the widening of the hysteresis loop in nanocomposites in relation to pure nanoparticles were also found. In turn, the FT-MIR spectroscopy method was used to check the influence of the impurity concentration on the formation/disappearance or modification of the absorption bands, and the modification of both the FWHM and the maximum positions for the four selected vibrations in the MIR range, as well as the discontinuous behavior of these parameters at the phase transitions, were found.

Validation of the infrared spectroscopy method for analysis of the composition of urine concretes

The aim of this study was to validate the method for analyzing the composition of calculus using infrared (IR) spectroscopy by studying model mixtures of salts. Study was made with an ALPHA-P IR Fourier spectrometer with OPUS software (Bruker, Germany). The samples of pure chemical salts manufactured by Sigma-Aldrich USA were used to validate the method. Salt mixtures were prepared in ratios of 10/90, 50/50 and 90/10. To assess the effect of the fraction size on the calculus component results, were used calculi of patients with urolithiasis. For each mixture were used 10 repeated measurements. Analysis of the composition of model salts showed that in the study of pure cystine salt CV(%) was 0,79%, calcium carbonate - 0,92%, sodium urate - 0,97%, calcium oxalate monohydrate - 4,94%, magnesium ammonium phosphate - 5,59%. And the most common components were analyzed in the composition of complex mixtures, including 90%, 50% and 10% of the investigated component. Calcium oxalate monohydrate has CV(%) 5.70% in mixture 9 part of it to one part of impurities, in mixture 50/50 - 21.57% and in 10/90 - 5.70%. For uric acid in 90/10 - 2.20%, in 50/50 - 10.09%, in 10/90 - 31.94%. For calcium carbonate in 90/10 - 9.02%, in 50/50 - 11.98%, in 10/90 - 24.70%. The dispersion analysis showed that the weighed portions of salts with a particle diameter of more than 0.8 mm provide reproducibility with a CV - 11.48%, with a diameter of 0.2-0.8 mm - 5.35%, and finally less than 0.1 mm - 2.28%. The accuracy of the method is high, but the reproducibility of the IR-spectroscopy method is relatively low in the analysis of stones of mixed composition, due to the greater error in the determination of impurities. Laboratories should pay special attention to optimizing sample preparation to ensure particle fineness less than 0.1 mm.

Diagnostics of Advanced Power Intensive Power Sources Based on the Acoustic Spectroscopy Method

Objective of this article is to develop a method for lithium chemical current sources diagnostics, which would ensure high reliability in assessing their technical state (primarily, the discharge degree) close to potentially achievable introduction of the acoustic spectroscopy method. Today, microcalorimetric studies and methods of impedance and noise spectroscopy make it possible to predict the lithium chemical current sources service life. However, implementation of the microcalorimetric studies result requires a lot of time accompanied by using stationary and large-size equipment, which is practically impossible in the autonomous conditions. Application of the impedance spectroscopy method provides satisfactory results only with high degrees of discharge. In the range of 0--30 %, it is very difficult to determine the discharge degree, since noticeable alteration in the correlate within its deviation from the mean value is missing. In this regard, it is proposed in order to provide diagnostics of the lithium chemical current sources in the region of initial degrees of discharge to introduce the noise diagnostics method. In order to increase reliability of the diagnostic estimates, it is advisable to use acoustic spectroscopy as a physically independent method in diagnosing the state of lithium chemical current sources. Results of the preliminary measurements analysis confirm the prospects of using the acoustic spectroscopy method in assessing the current state of primary lithium chemical current sources. Experimental studies of the lithium chemical current sources response to acoustic (mechanical) action made it possible to determine a set of parameters characterizing the proposed methodological approach. This provided a possibility to search for correlation dependences of the lithium chemical current sources spectral characteristics on the degree of their discharge. This makes it possible to use the method of acoustic spectroscopy in prompt and reliable diagnostics of the primary current sources in the region of low discharge degrees

EXPRESS ANALYSIS OF TRIETHOXYSILANE AND TETRAETHOXYSILANE USING THE RAMAN SPECTROSCOPY METHOD FOR OPTIMIZATION OF THE TECHNOLOGICAL PROCESS OF MONOSILANE SYNTHESIS

A technique for the express analysis of the products of technological processes is described, which was developed using the Raman spectroscopy method. The analysis of the Raman spectra includes the interpretation of the spectral bands, taking into account the values of the characteristic frequencies of the vibrational spectra of organic compounds, as well as the determination of the integral intensities of the corresponding spectral ranges. By example of the real time control procedure for the technological process of monosilane synthesis, the express analysis of tetraethoxysilane, which is a by-product of this technological process, is carried out. Significant advantages of using the express analysis method are demonstrated, which provide control over the normal course of the technological process and obtaining results that allow making adjustments to the process flow diagram in order to optimize it.

Spectral analysis of juvenile dentin biomaterials

The experiments in optical evaluation of biomaterials taken from juvenile dentin have been made using the Raman spectroscopy method. It was shown that juvenile teeth lose their mineral components and preserve organic components in the process of demineralization with the use of hydrochloric acid.