Materials Literature
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The HH and HV Raman spectra of vitreous silica are calculated from first principles for a model structure consisting of a disordered network of corner-sharing tetrahedra, for which the vibrational properties were obtained previously. We analyse the contribution of specific atomic motions to the Raman spectra and perfo…
The effect of synchrotron radiation (SR) irradiation of a polytetrafluoroethylene (PTFE) surface was investigated using X-ray photoelectron spectroscopy (XPS). After the SR irradiation, the relative intensity of the F 1 s peak to the C 1 s peak decreased markedly. The chemical composition ratio of the F atoms to C ato…
Selective H/D kinetic isotope effects (KIEs) have been determined for the various routes by which • OH radicals react with ethanol (CH 3 CH 2 OH and CD 3 CD 2 OH) and methylamine (CH 3 NH 2 and CD 3 NH 2 ) in H 2 O solutions. The KIEs have been evaluated from overall rate constants and the yields in which the individu…
Copolymers containing nonhomopolymerizable γ-butyrolactone (BL) and ε-caprolactone (CL) units of different compositions were synthesized by the ring-opening polymerization method using the SmI 2 /Sm initiator system. A maximum of 33 mol % of BL was incorporated into polycaprolactone (PCL) backbone. The microstructure…
The paper presents the results of measurements of the linear dielectric properties of the compounds from the homologous series of alkylcyanobiphenyls (C(n)H(2n+1)PhPhCN, nCB) in the vicinity of the first order transition (from the isotropic liquid to the crystalline phase) of nonmesogenic nCB's (n=2-4) and the weakly…
Temperature modulated differential scanning calorimetry measurements on Ag y (Ge x Se 1− x ) 1− y glasses provide evidence for bimodal glass transition temperatures in Se-rich glasses ( x < 1/3). At x = 0.20 and 0.25, thermal measurements performed as a function of Ag content in the 0 ≤ y ≤ 0.25 range reveal that the…
Using photoluminescence and Raman scattering, we have studied the optical properties of Mn-doped ZnS nanocrystallites prepared by a microemulsion-hydrothermal method. The PL spectrum shows two distinct peaks in the blue-green region. The PL peak from the nanoparticles, in the region 400–480 nm (3.1–2.6 eV), shifts tow…
Vibrational properties of Ba doped Si clathrate are investigated at high pressures up to 20 GPa by Raman spectroscopy. Vibrations related with Ba encaged in the Si cages are observed below $100\text{ }\text{ }{\mathrm{c}\mathrm{m}}^{\ensuremath{-}1}$ by low-frequency Raman measurements of ${\mathrm{B}\mathrm{a}}_{8}{\…
We report on the nature of photothermally patterned regions inside self-assembled hydrogel nanoparticle materials containing coassembled colloidal Au. These composite materials are prepared from approximately 226-nm diameter particles composed of the environmentally responsive polymer, poly(N-isopropylacrylamide) (pNI…
This paper presents a unified theoretical picture of quasi-two-dimensional organic conductors in a new minimal model based on an anisotropic triangular lattice. These materials exhibit abundance of low-temperature physics, where the systematic understanding was lagging behind respective studies. This is ascribed to a…
The concept of matrix-mediated coupling assumes that coupling between movements of unlike cations in glass occurs in order to dissipate mechanical stresses created by small cations entering sites which are too large (e.g. Li+ ions entering empty sodium, ā, sites) and large cations entering sites which are too small (e…
Ion-conducting chalcogenide glasses have been chosen to illustrate three specific electrical effects in glasses and their relationship with the glassy structure. Firstly, the variation of conductivity with the mobile cation content was investigated for glasses from the systems Ag 2 S–GeS 2 , Ag 2 S–As 2 S 3 and x Ag 2…
Structure, transport properties, and electronic structure of epitaxial thin films ${\mathrm{La}}_{0.9}{\mathrm{Sn}}_{0.1}{\mathrm{MnO}}_{3}$ and ${\mathrm{La}}_{0.9}{\mathrm{Ca}}_{0.1}{\mathrm{MnO}}_{3}$ have been experimentally studied. According to the Hall-effect measurement, ${\mathrm{La}}_{0.9}{\mathrm{Sn}}_{0.1}…
Dielectric relaxation measurements of the ion dynamics in glassy, molten and crystalline ionic conductors show general properties independent of chemical composition and structure. These include the appearance of a near-constant loss at high frequencies/low temperatures and the transition to a many-particle ion-hoppin…
Hexagonal diamond (hDIA) and wurtzite-type BN (wBN) powders were synthesized using a Kawai-type high-pressure apparatus and the essential details of their structures were examined by Reitveld refinements in order to investigate their thermodynamic stability and transition mechanism. X-ray diffraction profiles of the p…
Highly Sensitive ZnO Ozone Detectors at Room Temperature, Bender, Marcus, Fortunato, Elvira, Nunes, Patrícia, Ferreira, Isabel, Marques, António, Martins, Rodrigo, Katsarakis, Nikos, Cimalla, Volker, Kiriakidis, George
Large-amplitude oscillatory shear alignment of a hierarchically ordered system of comb-shaped supramolecules and the preparation of core−corona nanorods thereof are reported. The supramolecules consist of nearly symmetric polystyrene- b -poly(4-vinylpyridine) diblock copolymers with pentadecylphenol side chains hydrog…
In this paper, we report the synthesis of well defined nanocomposite particles of polypyrrole (PPy) coated γ-Fe 2 O 3 . The nanocomposites with different γ-Fe 2 O 3 contents are generated by microemulsion polymerization of pyrrole by dispersing γ-Fe 2 O 3 in the oil phase. The structural properties of the nanocomposit…
The rate theory of irradiation effects in crystalline solids rests on a set of two ordinary differential equations which, for each type of point defect (vacancy and self-interstitial), describe the balance between the production of defects on the one hand and their annihilation on the other. The latter process occurs…
In order to study the high energy optical transitions i.e., 4f-to-5d (f-d) and charge-transfer (CT) spectra of trivalent rare earth (4f n -series, lanthanide) ions in crystal lattices, the luminescence excitation spectra of the series ions in LaPO 4 host lattices are measured in the vacuum ultraviolet (VUV)-ultraviole…