Materials Literature
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We have grown clean N-salicylideneaniline (SA) single crystals large enough for optical measurements. The photochromism of a SA single crystal is investigated at different optical polarizations. Based on theoretical calculations, the structure configurations of the SA molecules in the colored keto form are analyzed. W…
The composition dependence of the optical phonon modes has been investigated in ABi2B2O9 (A = Ba, Ca, Sr; B = Nb, Ta) and Bi3BTiO9 (B =Nb, Ta). The lowest under-damped modes at 293 K generally soften upon heating, except BaBi2M2O9 (M = Nb, Ta) of which A sites of pseudo-perovskite layers are occupied by large Ba ions.…
This work reports the transport of carbon dioxide, oxygen, and nitrogen in amorphous membranes of vulcanized natural rubber reinforced with regenerated cellulose. The values of the permeability coefficient of carbon dioxide, oxygen, and nitrogen in the composites with 25% of cellulose, measured at 25 °C and 15 cmHg of…
Abstract Charge-transfer complexes of bis(methylthio)tetrathiafulvalene (DMT-TTF) bisannulated macrocycles with 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ) were prepared. The crystal structural analysis revealed an intramolecular dimer structure with the π-π overlap of DMT-TTF units. The magnitude o…
Several metal catalysts were examined for their effectiveness in activating hydrogen peroxide and oxygen as oxidants for conversion of lignin models to benzoquinones. Good yields of quinones were observed when certain heteropolymetallates were used as catalysts in the presence of hydrogen peroxide. Oxygen was generall…
Dielectric studies of a PbHfO3 (lead hafnate) single crystal undergoing two structural phase transformations at about 163°C (436 K) and 209°C (482 K) were performed in broad frequency and temperature range. Special attention was paid to the paraelectric phase. Investigations of the complex dielectric permittivity in t…
Dielectric properties of the AgNbO3 (AN) and Ag1−xLixNbO3 ceramics with x = 0.02, 0.04, 0.06 were investigated at microwaves (MW, 36 GHz) in the temperature range of 100 ÷ 570 K. including the phase transitions in AN at 340K (weak ferroelectric - antiferroelectric) and at 530K (antiferroelectric-antiferroelectric). Th…
Abstract 1H NMR spin-lattice relaxation times T1 and T1ρ as well as the electrical conductivity were measured as a function of temperature in (n-C5H11NH3)2ZnCl4 and (n-C12H25NH3)2ZnCl4. The highest-temperature solid phase in both compounds was found to be the rotator phase, where rod-like cations perform uniaxial reor…
With the advances made in the past decade, catalytic incineration of volatile organic compounds (VOCs) has become the technology of choice in a wide range of pollution abatement strategies. In this study, a test was undertaken for the catalytic incineration, over a chromium oxide (Cr2O3) catalyst, of n-hexane, benzene…
Galvanic action between zinc and steel is an important property that contributes to the high corrosion resistance of zinc-coated steels. Quantitative knowledge of the galvanic throwing power (i.e., the area of the steel surface that is not covered with zinc but is galvanically protected by the coating in the surroundi…
Measurements are reported for the d.c. Kerr response and the pretransitional behaviour of a new liquid crystal, 4-cyanophenyl 4-pentylbenzoate at and above the nematic-isotropic phase transition temperature. The real parts of the third order nonlinear susceptibilities chi(3) at and above the nematic-isotropic transiti…
In addition to the known sterols and ketosteroids beta-sitosterol (24 alpha-ethylcholest-5-en-3 beta-ol), stigmasterol (24 alpha-ethylcholesta-5,22-dien-3 beta-ol), campesterol (24 alpha-methylcholest-5-en-3 beta-ol), beta-sitostenone (stigmast-4-en-3-one, 24 alpha-ethylcholest-4-en-3-one), stigmastenone (stigmasta-4,…
Abstract Reversibility in the formation reaction of a series of the oxo(peroxo)porphyrinatomolybdenums, [MoVIO(tmp)(O2)] 1, [MoVIO(tdcpp)(O2)] 2, [MoVIO(ttp)(O2)] 3, [MoVIO(tdmpp)(O2)] 4, and [MoVIO(tpp)(O2)] 5, was studied. In these dioxygen complexes with various porphyrin rings, two complexes, 2 and 4, were newly p…
Systematic studies on the sorption and diffusion behaviors of gases in low-molar-mass liquid crystalline substances (LCs) have been performed. The experiments were carried out in different gas atmospheres over temperature ranges which covered the phase transitions of the LCs under investigation, and at pressures of up…
A stable one-dimensional quasicrystal has been found for Al-Co-Ni which is related closely to the decagonal phase in this system. It exists as a high-temperature state above 900 C in a range of compositions between approximately 71 and 71.5at.% Al between 18at.% and 22at.% Co. The modulation length along the periodic…
Thin films of Cu 2 O were electrodeposited and characterised by techniques including XRD, SEM–EPMA, and spectrophotometry. The structure, morphology, composition, and optical properties of the films depend on the electrochemical bath and deposition parameters. The kind of substrate pretreatment process also seems to h…
Magnetic properties of Cd1−yMnyS nanocrystals have been studied. They vary with the particle size and markedly differ from those observed in the bulk phase, in particular their interactions drastically increase compared to those observed in the latter case. A Mn2+–Mn2+ interaction enhancement with decreasing size invo…
Crystalline ${\mathrm{Cs}}_{3}{\mathrm{Bi}}_{2}{\mathrm{I}}_{9},$ with the ${P6}_{3}/mmc$ symmetry at room temperature was studied by Laue and four-circle neutron diffractometry from room temperature down to 50 K. At ${T}_{0}=220 \mathrm{K}$ the crystal undergoes a second-order proper ferroelastic phase transition to…
The synthesis and applications of carbon nanotubes, a new form of crystalline carbon, are reviewed. In particular, the results obtained in the authors' laboratory are summarized, including the preparation of highly crystalline multi-walled carbon nanotubes; also discussed are the valence band and core level structures…
The morphology, thickness, oxidation and illumination effects in dodecylsulphate doped polypyrrole films can be qualitatively observed by EIS and consist in variations of interfacial and bulk resistances and capacitances of a proposed equivalent circuit. The circuit well with the measured spectra of films obtained wit…