Materials Literature
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The dielectric properties and the effect of hydrostatic pressure on the successive phase transitions have been studied for single crystal CH3NH3PbX3 (X: Cl, Br, I). Anisotropic anomalies in dielectric constant at phase transitions are obtained. The pressure (p)-temperature (T) phase diagrams are shown for the three CH…
The results of an x-ray diffraction study of dc-magnetron sputtered tungsten thin films are reported. It is shown that the phase transformation from the β to α W can cause multilayered single-phase films where the layers have very different stress states even if the films are in the 500 nm thickness range.
A new crystalline polymorph of Bombyx mori silk, which forms at the air–water interface, has been characterized. A previous study found this structure to be trigonal, and to be distinctly different than the two previously observed silk crystal structures, silk I and silk II. This new structure was named silk III. Iden…
Thin films of a simple organosilane, propyltrimethoxysilane (PTMS), on polycrystalline aluminium and iron oxide substrates have been investigated using XPS. Comparison of the adsorption isotherms for the two substrates reveals significant differences between them. Although PTMS on iron oxide exhibits a Langmuir-like i…
Phosphorylcholine groups attached to polymer surfaces are known to improve hemocompatibility. A photochemical method is presented to couple phosphorylcholine-containing aryl azides to poly(etherurethane) surfaces (PEUs). Two aryl azides that consist of a photoactivatable 4-azidobenzoyl group, a short spacer chain, and…
The pressure dependence of the Raman spectra of SrTiO3 was investigated up to 15.5 GPa. The anti-ferrodistortive cubic–tetragonal phase transition (phonon condensation at the R point of the Brillouin zone) occurs at about 6 GPa. The strong, broad bands, present under ambient conditions, sharpen and change their profil…
The development of a process for the synthesis of methyl methacrylate (MMA) from coal-derived syngas can alleviate the environmental hazards associated with the current commercial MMA technology, the acetone cyanohydrin (ACH) process. A three-step syngas-based process consisted of synthesis of a propionic acid, its co…
A physical approach is used to analyse the various mechanisms induced by the absorption of X‐ray photons of energies in the 0.2–20 keV range. At the atomic scale, besides the (Auger and photo) electron transport in the bulk or the ejection into the surrounding media, special attention is devoted to the specific conseq…
The electronic structure, lattice parameters, phonon frequencies at the Brillouin zone center, and first-order elastic constants ( C ij ) have been calculated at the ab initio Hartree−Fock level using either all-atomic-electron basis sets or basis sets associated with core pseudopotentials. Band structure, electronic…
An iron and cobalt K-edge X-ray absorption study has been undertaken, at 295 and 77 K, to investigate the electronic spin states of Fe[HB(pz) 3 ] 2, 1, Fe[HB(3,5-(CH 3 ) 2 pz) 3 ] 2, 2, Fe[HB(3,4,5-(CH 3 ) 3 pz) 3 ] 2, 3, Co[HB(pz) 3 ] 2, 4, Co[HB(3,5-(CH 3 ) 2 pz) 3 ] 2, 5, and Co[HB(3,4,5-(CH 3 ) 3 pz) 3 ] 2, 6, whe…
Binary and ternary blends of polystyrene- block -poly( p -hydroxystyrene) (MW = 1 × 10 4 −1 × 10 4 ) with various homopolymers were studied. In binary blends, in which the homopolymers poly(ethylene oxide) (PEO), poly( p -vinylpyridine) (PVPy), and poly( n -butyl acrylate) (P n BA) had attractive interactions via hydr…
Bis-π-cyclopentadienyl nickel has been proposed as a source material for metalorganic chemical vapor deposition of nickel oxide films. The transparent film deposited at 310°C was of a NaCl-type crystal structure of NiO. The refractive index and optical bandgap were approximately 2.1 and 3.7 eV, respectively.
The decomposition of the cyanine dye, pinacyanol chloride, has been studied using hydrogen peroxide and several mixed valent manganese oxide catalysts in aqueous, alkaline solution at room temperature. These catalysts belong to a class of porous manganese oxides known as octahedral molecular sieves (OMS). The most act…
We have measured the room temperature (RT) and 20 K luminescence lifetime of ${\mathrm{Cr}}^{3+}$ in yttrium aluminum garnet as a function of pressure up to 240 kbar. The RT lifetime changed from 1.7(1) ms at ambient pressure to 42(2) ms at 220 kbar and the 20 K lifetime from 8.8(1) ms at ambient pressure to 67(2) ms…
In the sol−gel Cu/TiO 2 system, nanocrystalline brookite, which was stable even after annealing the sample at 400 °C, was generated in high concentrations. This was achieved with copper chloride as copper precursor. The respective samples had a light absorption band at 562 nm that corresponded to an energy bandgap of…
Polycarbosilane/siloxane hybrid polymers were synthesized by sol−gel processing of the cyclic organosilicon compound 1,1,3,3-tetraethoxy-1,3-disilacyclobutane (CBS) and the linear polymer poly(diethoxysilylenemethylene) (L-EPCS) derived from CBS by ring-opening polymerization. The structure of these polymers and their…
The growth and decay processes of the optically induced birefringence in an azobenzene-functionalized polymer, DR19FPOZ (full name given in the text), and in another azobenzene guest/host polymer system have been studied. The temperature dependence of the birefringence signal is studied, and possible mechanisms associ…
Liquid metal induced embrittlement (LMIE) refers to the loss of ductility of normally ductile metals and alloys when stressed while in contact with a liquid metal. Various models have been proposed to describe the mechanisms by which LMIE failure takes place. In the present study the most promising of these are discus…
Abstract Nylon-6 and acrylate rubber (ACM) were melt blended in a Brabender Plasticorder at 220 °C and 40 rpm rotor speed. The reactive nature of the blend is reflected in the mixing torque behavior of the blends at different compositions. The solubility characteristics of the blends in formic acid solution gives an a…
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