Materials Literature
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A model is presented to explain the transition of the angular distribution of valence-band photoelectrons from the low-energy regime, characterized by emission only along the Mahan cones, to the high-energy regime, characterized by emission patterns very similar to those of core-level photoelectron diffraction. The tw…
SYNOPSIS The synthesis of substituted 2-phenyl-benzoxazoles has been accomplished by ring closure of Schiff bases. The compounds have been used as precursors of acrylic derivatives displaying LC properties : formula chem. R 1 = NO 2 , CN ; R 2 = -OOC-pC 6 H 4 -O(CH 2 ) 6 OOCCH=CH 2 ; R 1 = - OOC - pC 6 H 4 - O(CH 2 )…
We have investigated the physical and electrical properties of anodic oxide films treated by a variety of aqueous electrolyte solutions. All anodic oxide diodes revealed consecutive current regimes varying with bias voltage as V, V2, and Vn (n≳2) in the steady-state current-voltage characteristics. Here, the transitio…
Selected area electron-diffraction (SAED) investigations were performed on La-modified (1−x)Pb(Mg1/3Nb2/3)O3–x(PbTiO3) ceramics for compositions near the morphotropic phase boundary for various nonstoichiometric ordering conditions of Mg and Nb on the B-site cation positions. Studies were performed on specimens with L…
An important issue for the epitaxial growth of strained Si1−yCy alloy layers is the relation between substitutional and interstitial carbon incorporation, which is strongly influenced by the growth conditions. We use in vacuu x-ray photoelectron spectroscopy (XPS) to investigate Si1−yCy layers (y<2 at. %) grown…
The light-emitting porous silicon is treated by the rapid thermal process at 900–1100 °C under NH3 environment. The infrared absorption spectra and Auger electron spectra show that the surface of porous silicon is covered with a nitride-containing layer. From the electron spin resonance, the density of dangling bonds…
The synthesis of fluorinated hybrid silicones prepared in three steps from H2CCH—C6F12CHCH2(I) and H2CCHCH2—C6F12—CH2CHCH2(II) is presented. First, both hydrosilylations of chlorodimethylsilane with these nonconjugated dienes were carried out in the presence of the Speier's catalyst leading to the expected bis-ch…
Organic-inorganic nanocomposite gels comprising poly(ethyleneoxide) chains grafted between silica particles have been studied by electron paramagnetic and nuclear magnetic resonances. Motional heterogeneity has been investigated as a function of gelation and drying by paramagnetic probes dissolved in the organic phase…
We have experimentally studied the photoluminescent (PL) properties of Si clusters in fused silica matrices. Si clusters in the ${\mathrm{SiO}}_{2}$ matrices were fabricated by ${\mathrm{Si}}^{+}$-ion implantation (200 keV, 2\ifmmode\times\else\texttimes\fi{}${10}^{17}$ ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}2}$) into…
ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTEfficient Synthesis of 2,11,20-Triaza[3.3.3](2,6)pyridinophaneGeunsu Lee, Masakazu Oka, Hiroyuki Takemura, Yuji Miyahara, Nobujiro Shimizu, and Takahiko InazuView Author Information Department of Chemistry, Faculty of Science, Kyushu University, Hakozaki, Higashi-ku, Fukuoka 81…
High molecular weight copolyesters were prepared by the acidolysis of poly(ethylene terephthalate) with p-acetoxybenzoic acid and polycondensation through the acetate and carboxyl groups. The mechanical properties of the injection-molded copolyesters containing 40–90 mole- % p-hydroxybenzoic acid (PHB) were highly ani…
We have investigated the operating parameters controlling the average roughness Ra of diamond films obtained through chemical-vapor deposition using microwave-sustained plasmas. The plasma was provided by a surface-wave discharge in the form of a convex hemisphere facing the substrate and the films were deposited on S…
In this work the anharmonic contributions to the high-temperature EXAFS spectra have been evaluated by considering the anharmonic contributions to the thermal vibrations of atoms and using the single-shell model. The anharmonicity calculated by our new formula is proportional to the temperature and inversely proportio…
The electronic structure of heazlewoodite ${\mathrm{Ni}}_{3}$${\mathrm{S}}_{2}$ has been studied within the local-density approximation, using an extended general-potential linearized augmented-plane-wave method. The calculation indicates that unlike many other transition-metal sulfides and oxides, ${\mathrm{Ni}}_{3}$…
An experimental study has been made on the interaction of an underwater shock wave with two air bubbles attached to a gelatin surface. The shock wave was generated by detonating a microexplosive pellet, and the subsequent behavior of bubble collapse was visualized by high-speed photography. By measuring the directivit…
A multiordering parameter model for glass-transition phenomena has been developed on the basis of nonequilibrium thermodynamics. In this treatment the state of the glass is determined by the values of N ordering parameters in addition to T and P; the departure from equilibrium is partitioned among the various ordering…
By using angle-resolved ultraviolet photoelectron spectroscopy, x-ray photoelectron spectroscopy, and work function measurement, we have explored the electronic states of the heteroepitaxial double-layer (HEDL) system composed of Ni(111), monolayer hexagonal boron nitride, and graphite overlayer. Present data clearly…
A survey of potential shallow n-type donors in diamond was performed using the atom superposition and electron delocalization molecular-orbital method. Electronic structure and defect stabilities were estimated for N, P, O, S, F, and Cl in substitutional monovacancy sites; I, Xe, and the atom pairs BO, BS, NO, NS, and…
Due to the inherent simplicity of the graphene tubule systems, it is expected that these systems will become model systems for the calculation of the mechanical and electronic properties of idealized carbon fibers. In this paper the collective electronic excitations on graphene tubules are discussed. The frequencies o…
The synthesis of the first derivatives of bis(pyrrolo[3,4-d])tetrathiafulvalene has been studied in detail. Starting from the readily available 2,5-dimethylpyrrole (11) and N-phenyl-2,5-dimethylpyrrole, bis(2,5-dimethylpyrrolo[3,4-d])tetrathiafulvalene (8) and the N,N'-disubstituted derivatives 6, 7, 9, and 10 were pr…