Ferroelectric properties of LC systems including chiral dopants with different molecular structure

Abstract— New ferroelectric liquid crystals (FLCs) on the basis of the eutectic mixture of phenylbenzoate derivatives including chiral components (CCs) with a different number and position of carbonyl groups in their molecular core have been investigated. The ferroelectric characteristics such as the spontaneous polarization, smectic tilt angle, rotational viscosity, and repolarization time as well as their concentration dependences are analyzed. On the basis of the previous and obtained results, the influence of peculiarities of the molecular structure of CCs on mentioned properties of FLCs are generalized.     

Features of obtaining an effective catalyst for synthesis of carbon nanostructured materials

Abstract

In the present paper, the features of obtaining a metal oxide Fe–Co/Al₂O₃ catalyst for the synthesis of carbon nanostructured materials through thermal decomposition are considered. It was experimentally proved that the temperature and duration of the stage of thermal decomposition of the initial components solution significantly affect the catalyst activity in the synthesis of carbon nanostructured materials by the CVD method. It was found that controlling the mode parameters of the thermal decomposition of the initial components solution of the Fe–Co/Al₂O₃ catalyst, one can not only obtain a catalyst with the required characteristics but also directionally synthesize carbon nanostructured materials over the resulting catalytic systems. During the experiments, rational modes for the implementation of the method for producing catalysts were determined, allowing to form a metal oxide system with a specific surface area of 108?m²/g, the use of which in the synthesis of carbon nanostructured materials leads to the formation of multi-walled carbon nanotubes with an external diameter of 30?nm.     

Anti-Atherosclerotic Effects of a Phytoestrogen-Rich Herbal Preparation in Postmenopausal Women

The risk of cardiovascular disease and atherosclerosis progression is significantly increased after menopause, probably due to the decrease of estrogen levels. The use of hormone replacement therapy (HRT) for prevention of cardiovascular disease in older postmenopausal failed to meet expectations. Phytoestrogens may induce some improvements in climacteric symptoms, but their effect on the progression of atherosclerosis remains unclear. The reduction of cholesterol accumulation at the cellular level should lead to inhibition of the atherosclerotic process in the arterial wall. The inhibition of intracellular lipid deposition with isoflavonoids was suggested as the effective way for the prevention of plaque formation in the arterial wall. The aim of this double-blind, placebo-controlled clinical study was to investigate the effect of an isoflavonoid-rich herbal preparation on atherosclerosis progression in postmenopausal women free of overt cardiovascular disease. One hundred fifty-seven healthy postmenopausal women (age 65 ± 6) were randomized to a 500 mg isoflavonoid-rich herbal preparation containing tannins from grape seeds, green tea leaves, hop cone powder, and garlic powder, or placebo. Conventional cardiovascular risk factors and intima-media thickness of common carotid arteries (cIMT) were evaluated at the baseline and after 12 months of treatment. After 12-months follow-up, total cholesterol decreased by 6.3% in isoflavonoid-rich herbal preparation recipients (p = 0.011) and by 5.2% in placebo recipients (p = 0.020); low density lipoprotein (LDL) cholesterol decreased by 7.6% in isoflavonoid-rich herbal preparation recipients (p = 0.040) and by 5.2% in placebo recipients (non-significant, NS); high density lipoprotein (HDL) cholesterol decreased by 3.4% in isoflavonoid-rich herbal preparation recipients (NS) and by 4.5% in placebo recipients (p = 0.038); triglycerides decreased by 6.0% in isoflavonoid-rich herbal preparation recipients (NS) and by 7.1% in placebo recipients (NS). The differences between lipid changes in the isoflavonoid-rich herbal preparation and placebo recipients did not reach statistical significance (p > 0.05). Nevertheless, the mean cIMT progression was significantly lower in isoflavonoid-rich herbal preparation recipients as compared to the placebo group (6 μm, or <1%, versus 100 μm, or 13%; p < 0.001 for the difference). The growth of existing atherosclerotic plaques in isoflavonoid-rich herbal preparation recipients was inhibited by 1.5-fold (27% versus 41% in the placebo group). The obtained results demonstrate that the use of isoflavonoid-rich herbal preparation in postmenopausal women may suppress the formation of new atherosclerotic lesions and reduce the progression of existing ones, thus promising new drug for anti-atherosclerotic therapy. Nevertheless, further studies are required to confirm these findings.     

Quantum interference and Shubnikov–de Haas oscillations in β″-(ET)4(H3O)[Fe(C2O4)3]·C6H4Cl2 under pressure

Magnetoresistance oscillations of the quasi-two dimensional charge transfer salt β″-(ET)₄(H₃O)[Fe(C₂O₄)₃]·C₆H₄Cl₂ are investigated in pulsed magnetic fields of up to 55 T, under an applied pressure of 0.5 GPa. As it is the case at ambient pressure, data are in agreement with the coexistence of a Shubnikov–de Haas orbit and a quantum interference path with the same cross section. As a result, oscillations are observed at temperatures as high as 25 K.     

Mesoporous Structure and Photocatalytic Activity of Doped Polyanilines

Photocatalytic activity of doped polyaniline nanopowders with different molar ratio of An/O （aniline~oxidizer） has been studied in the process of photocatalytic decolorization of aqueous solutions of methylene blue. By means of scanning electron microscopy and low-temperature N2 adsorption method, it was found that doped PANI （polyaniline） nanopowders have the particles size of 30-50 nm with the specific surface area of 20-35 m2.g＂~. It was found that PANI photocatalytic activity essentially depends on molar ratio of An/O and adsorption interactions between the dye molecules and catalytic active centers on PANI surface and these interactions are greatly affected by pH of the solution 9.2. An optimum of the synergetic effect is found for an initial molar ratio of aniline to oxidizer equal to 0.8.     

Structural evolution in copper layers during sliding under different lubricant conditions

Friction and wear of copper rubbed in a wide range of loads and sliding velocities were studied. The results of friction and wear experiments in PAO-4 lubricant are presented as the Stribeck curve where the boundary, mixed and elasto-hydrodynamic lubrication regimes are considered. The structural state of surface layers in different lubricant regimes is studied by optical and scanning electron microscopy and X-ray photoelectron spectroscopy analyses. The dominant friction and wear mechanisms in different lubrication regimes are discussed. Severe plastic deformation of subsurface layers under friction is correlated with the nanocrystalline structure obtained by different methods of grain refinement.     

Thermal analysis of new ITER FW and divertor design during VDE energy deposition

Further developments and investigations in the area of fusion energy devices require extensive and comprehensive computer simulations with great precision to evaluate reactor components behavior during normal and transient events. In this work we performed detailed study of the first wall (FW) subjected to high heat flux during a vertical displacement event (VDE) with various initial steady-state conditions and heat flux histories for the transient plasma energy deposition. We calculated the spatial temperature profile through out the entire module and the maximum surface temperature, as well as melting and vaporization thickness of Be surface during VDE and just before thermal quench (TQ). We further studied possible potential damage to plasma facing components (PFC) and structural materials for VDEs with higher energy loads than currently estimated.     

Thermodynamic Analysis and Experimental Study of Composite Structure Formation in Eutectic Alloys α -Al + Mg2Si

The Al ― Mg ― Si phase diagram was studied and the formation conditions for a regular two-phase eutectic structure (α-Al + Mg₂Si) were established. Concentration limits were found for optimum alloy compositions with maximum melting point (～595°C) and a narrow (or zero) melting (crystallization) range (less than 5°C). The structures of these alloys are formed by Mg₂Si monocrystal fibers and lamellae with a high degree of ordering, located in the aluminum matrix.     

Laws of Reduction of NO with Carbon Monoxide Using a Magnetic Field Effect

We first received the previously unknown pattern of the magnetic field and relativistic effects on chemical reactions in catalysis for example, reduction NO with monooxide carbon with used magnetic uranium catalysts, which is to reduce the activation energy of the reactants with increasing concentration of magnetic materials and due to the interaction and control of the motion of ions and electrons with atoms and attraction between ions by means of a magnetic field.