Materials Literature
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Abstract The molecular structure of a reversible oxygen carrier, MoVIO(tmp)(O2) has been characterized by X-ray crystallography. Oxo and dioxygen ligands are actually coordinated with cis conformation, which leads to a saddle-like distortion of the porphyrin ring. The result of 2D ROESY shows the distortion of the por…
Ferroelectric properties of 9% mol (Hf, Zr) - doped BaTiO3 ceramics are studied by comparison with those of tetragonal pure BaTiO3 ceramics. A shift of the rhombohedral-orthorhombic and orthorhombic-tetragonal transition temperatures above 0°C and a decreasing of tetragonal-cubic transition temperature from 122°C to 9…
Ceramic chips of beryllium oxide were exposed to high energy heavy ion beams (He, C, Ne, Ar and Fe) and the glow curves were analysed. Two comparable peaks at around 203 oC and 355 oC were found and each peak height showed a different LET dependence. The low temperature peak height (IL) increased remarkably with LET t…
Bei der Neuuntersuchung des Phasendiagramms RbCl/PbCl2 mit differenzthermoanalytischen und röntgenographischen Methoden wurde die Bildung zweier ternärer, bisher noch nicht bekannter Phasen mit den Formeln Rb6Pb5Cl16 und Rb3PbCl5 gefunden, die beide in neuen Strukturtypen kristallisieren. Beide Phasen zersetzen sich p…
It is shown that steric interactions of volume substituents in the β-positions of pyrrole rings and the nitro group in mono-and di-meso-phenyl-substituted of octaethylporphyrins and their chemical dimers containing the electron-acceptor NO2 group in the ortho-position of the phenyl ring at 295 K favor the direct overl…
Electrochemical synthesis of polyaniline was carried out in aqueous sulfuric acid solutions of aniline on porous p- and n-silicon under galvanostatic, potentiostatic and potential pulse regimes. It is shown that the introduction of catalytic quantities of oxidants, potassium hexachloroiridate, potassium dichromate, po…
Ab initio Hartree-Fock molecular orbital calculations were applied to the crystalline imidazole and its derivatives in order to examine systematically the effect of possible N-H---N type hydrogen bond-ing on the nuclear quadrupole interaction parameters in these materials. The nitrogen quadrupole coupling constant (QC…
Abstract Blends of two precursor polymers, polyhydroxy amide (PHA) and poly(amic acid) (PAA), were studied using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The presence of PHA enhanced thermal and mechanical properties of the polyblends. All of the polyblended films showed large endo…
A series of liquid crystalline cyclic siloxane tetramers was prepared to investigate, in a systematic manner, the role of molecular structure of (a) the spacer group, (b) the mesogenic side group and (c) the chiral end group, on the liquid crystalline behaviour of these novel tetramers. The results from this systemati…
The influence of a cationic surfactant, N‐cetyl‐N, N, N‐trimethyl ammonium bromide (CTAB) on the inhibition efficiency (IE) of calcium gluconate (CG) – Zn 2+ system in controlling corrosion of mild steel in a neutral aqueous environment containing 60ppm Cl ‐ has been evaluated by weight‐loss method. The formulation co…
The synthesis of some new 4-alkoxyl-4′-cyano-p-terphenyls is described. The preliminary characterization by means of polarized optical microscopy, differential scanning calorimetry and X-ray diffraction shows that all these compounds are thermotropically liquid-crystalline and can form both the nematic and smectic mes…
Crystalline yttrium carbonate, Y2(CO3)3·2.79H2O, was synthesized using ammonium bicarbonate as precipitant. The X ray diffraction data were indexed in the triclinic system with cell parameters a = 19. 076Å, b = 22. 312Å, c = 7. 823Å, α = 94. 493°, β = 91. 397° and γ = 112. 663°. The structure is closely related to tho…
The pressure dependence of the structural phase transition temperature has been measured for the powder samples of NH4MgF3, NH4ZnF3, NH4MnF3, NH4CoF3, NH4CdF3, and NH4MnCl3 perovskites in the pressure range 0 to 600 MPa. It was found that the values of dT0/dP are negative for the Mg, Zn, Co, Mn trifluorides and positi…
The palladium(II) and platinum(II) complexes of 1,4-oxatellurane ( L ), having the composition [MCl 2 L 2 ], are synthesized and characterized spectroscopically and structurally (Pt complex only; Pt–Cl 2.3169(9) Å; Pt–Te 2.5945(3) Å) for the first time.
Tin oxide films were produced by chemical vapor deposition using monobutyltin trichloride and oxygen as reactants. The effect of H 2 O addition on deposition behavior and electrical properties at various deposition temperatures were investigated. The addition of H 2 O significantly increased deposition rates and lower…
The Neumann and Young equations for three-phase nematic contact lines have been derived using the momentum balance equation and classical liquid crystal physics theories. The novel finding is the presence of bending forces, originating from the anchoring energy of nematic interfaces, and acting on the contact line. Th…
Abstract The crystal structure of strontian potassicrichterite (Mg 4.871 Fe 0.126 3+ Mn 0.052 ) Σ5.049 (Na 1.425 Ca 0.348 Sr 0.297 ) σ2.07 K 0.873 Si 8.048 O 22 (OH) 2.15 – an unusual amphibole containing up to 3.7 wt.% SrO from the Murun alkaline massif, Eastern Siberia has been refined from X-ray powder diffraction…
A technique of hydrophobic surface design with a high degree of structural homogeneity has been developed for catalytic materials. Mesoporous activated carbons and silica gel were modified by (A) treatment with vinyltrimethoxysilane (vtms) or (B) chlorination with carbon tetrachloride followed by reaction with a Grign…
Abstract The Mössbauer and infrared spectra of Li- and Rb-saturated nontronites from Washington, USA (SWa-1), heat treated at different temperatures, were measured. The Mössbauer results show that diffusion of Li + into the 2:1 layer by heat treatment at 250-300°C does not affect the magnetic hyperfine interactions of…
A general method to describe the instrumental resolution function for grazing-angle X-ray scattering experiments is presented. A resolution function {\scr R} is introduced as the Gaussian joint-distribution function of the (interdependent) random deviation q ′ associated with the wavevector transfer q . Useful express…