Materials Literature
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The magnetic structures of tetragonal La 0.8 Y 0.2 Mn 2 Si 2 have been investigated by neutron diffraction measurements over the temperature range ~2 - 513 K. This compound corresponds to the critical concentration x c ~ 0.2 in the La 1 - x Y x Mn 2 Si 2 series for the transition from the antiferromagnetism of YMn 2 S…
Density functional quantum chemical calculations have been used to compare the acid strengths of phosphotungstic and phosphomolybdic acids by computing the adsorption energy of ammonia on model clusters of each heteropolyacid. The adsorption of ammonia on a phosphotungstic acid cluster was stronger than the adsorption…
Char oxidation is often modeled using an m th order intrinsic reaction rate in conjunction with an effectiveness factor (η) to account for intraparticle diffusion of gas species. This approach involves the use of a general modulus ( M T ) and using the first-order curve of η vs M T . This method was originally referre…
A study of the influence of employing ultrahigh molecular weight polyethylene (UHMWPE) on the toughness of CaCO3/high-density polyethylene (HDPE) composites was carried out. Binary and ternary HDPE-based composites with calcium carbonate in the range of 0–40% and UHMWPE in the range of 0–50% were produced by twin-scre…
Melon-seed and rubber-seed oils have been used in the synthesis of polyester resins. Results reveal that rubber-seed oil can completely be substituted for linseed and soyabean oils in the synthesis of both long and medium-oil–length polyester resins. Melon-seed oil was found to be a substitute for 50% of linseed oil a…
Tris(2,2‘-bipyridine)ruthenium(II) ([Ru(bpy) 3 ] 2+ )−fluortetrasilicic mica−poly(vinylpyrrolidone) intercalation compounds were prepared by the intercalation of poly(vinylpyrrolidone) into the presynthesized [Ru(bpy) 3 ] 2+ −fluortetrasilicic mica intercalation compounds. The formation of the intercalation compounds…
2,2′-Mercaptoethylsulfide dimethacrylate (MESDMA) was synthesized from 2,2′-mercaptoethylsulfide (MES) by a Phase-Transfer Catalysis technique and, was characterized and corroborated by 1H-NMR and FTIR spectra. Except for the poor impact strength, the MESDMA homopolymer resin shows better comprehensive properties, suc…
Sulfur-cured filled natural rubber (NR) is successfully reclaimed by using a renewable resource material (RRM) and diallyl disulfide (DADS), which is the major constituent of RRM. Reclaiming of NR vulcanizate was carried out at 60°C for 35 min in an open two-roll mixing mill. Evaluation of the properties of NR reclaim…
Electrical-transport properties of protonic acid (H2SO4 and HCl)-doped polyaniline (PANI) in an aqueous ethanol medium were investigated in the temperature range 1.8 K ≤ T ≤ 300 K and in a magnetic field up to 8 T. The room-temperature resistivity of HCl-doped PANI is larger than that of H2SO4-doped PANI. The resistiv…
Natural rubber (NR) was blended in various ratios with 29 kinds of tackifier resins. Miscibilities of all the blend systems were illustrated as phase diagrams. From these blend systems, we selected 8 systems having typical phase diagrams (completely miscible, immiscible, lower critical solution temperature [LCST] type…
An induction-coupled plasma reactor was used to thermally decompose polypropylene into propylene and other useful chemicals. From a series of statistically designed experiments, it was found that plasma power input, sheath gas flow rate, central gas flow rate, powder feed rate, quench gas flow rate, and interaction of…
The electronic energy band structure, site- and angular-momentum-decomposed densities of states (DOS) and charge-density contours of perovskite SrTiO 3 in the paraelectric cubic phase are calculated by the first-principles tight-binding linear muffin-tin orbitals method with atomic sphere approximation using density f…
A series of degradable polyurethanes of variable soft segment chemistry and content were synthesized and characterized. An amino acid-based diester chain extender was used to confer degradability and both polycaprolactone diol (PCL) and polyethylene oxide (PEO) were used as soft segments. In addition, the diisocyanate…
The (Na 1 - x K x ) 0.5 Bi 0.5 TiO 3 perovskite solid solution is investigated using x-ray diffraction (XRD) and Raman spectroscopy in order to follow the structural evolution between the end members Na 0.5 Bi 0.5 TiO 3 (rhombohedral at 300 K) and K 0.5 Bi 0.5 TiO 3 (tetragonal at 300 K). The Raman spectra are analyse…
This letter reports the photoluminescence properties of CdSe quantum dots (QDs) embedded in a ferroelectric BaTiO3 matrix. The main emission from the samples has been assigned to the band–edge transition of QDs. With an increase in the heat treatment temperature, the emission peak has been shifted to a longer waveleng…
Both the Hall effect and the ab(')-plane conduction anisotropy are directly addressing the unconventional normal phase properties of the Bechgaard salt (TMTSF)2PF6. We found that the dramatic reduction of the carrier density deduced from recent optical data is not reflected in an enhanced Hall resistance. The pressure…
Scanning tunneling microscopy was used to study molecular order in monolayer organic films formed by solution-phase growth from thermotropic liquid crystal solvents. The films develop macroscopically uniaxial alignment, with adlayer orientation controlled by an external magnetic field through interactions mediated by…
Nanocomposite films consisting of nanosized Ag particles embedded in partially oxidized amorphous Si matrices were prepared by radio frequency cosputtering deposition. Subsequent heat treatment at different temperatures ranging from 200 to 500 °C and its effects on the optical absorption of the films were investigated…
Precise low-frequency light scattering experiments on silica glass are presented, covering a broad temperature and frequency range ( 9 GHz<nu<2 THz). The spectra show a power-law low-frequency wing of the relaxational part of the spectrum with an exponent alpha proportional to temperature in the range 30<T<200 K. A co…
We investigate, through first-principles calculations, the effects of a flattening distortion on the electronic properties of a semiconductor carbon nanotube. The flattening causes a progressive reduction of the band gap from 0.92 eV to zero. The band-overlap insulator-metal transition occurs for an interlayer distanc…