Materials Literature
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We report the first observation of the photoinduced absorption spectrum of the emeraldine base form of polyaniline. The spectrum contains both subgap photoinduced bleaching at 1.8 eV and photoinduced absorptions at 0.9, 1.4, and 3.0 eV, as well as band-edge bleaching above 3.5 eV. The existence of the subgap bleaching…
A theory of self-diffusion in concentrated dispersions is presented, in which the effects of hydrodynamic and direct interactions between macroparticles are virtually decoupled. The long-time self-diffusion coefficient ${D}_{s}^{L}$ is written in terms of the radial distribution function of the suspended particles and…
The native oxides formed on air exposed, etched bulk polycrystalline Zn3P2 were investigated in the as-etched condition, using x-ray photoemission spectroscopy. The sputter-etched surfaces appeared to be composed primarily of ZnO with a small concentration of P2O3 or phosphate underneath. The bromine-methanol etched s…
A detailed study is presented of the optical transmission through quasi-periodically layered media using a transfer matrix technique. The overall behaviour in multilayers arranged according to the Thue-Morse and Fibonacci sequences is found to be very similar. This is in strong contrast to the marked difference recent…
Miscibility in systems containing poly-2,2( m-phenylene)5,5'-bibenzimidazole (PBI) and a variety of aromatic polyimides (PI) has recently been reported.'-3 To study the intermolecular interactions in these blends, mixtures of benzimidazole (BI) and other similar aromatic compounds with PI in the polyamicacid (PAA) for…
Three sizes of CdSe molecular clusters were studied by $^{77}\mathrm{Se}$ NMR spectroscopy. The clusters are synthesized via arrested precipitation in a structured medium and are isolated as a molecular solid after modification of their surfaces with covalently attached organic ligands. While one component of the broa…
We present an approach for aggregating Penrose tiles to form a defect-free, 2D pentagonal quasicrystal tiling. Contrary to conventional wisdom, defect-free quasiperiodic tilings can be constructed by use of local rules alone. The results provide new insights as to how materials with only short-range atomic interaction…
Reduction in the activity and the concentration of the adsorbed enzyme are noted in the experimental data. Two alternative mechanisms, inactivation of the adsorbed enzyme and mass transfer of the enzyme from the bulk solution to the solution within the cellulose fibril where the cellulase is assumed to be inactive, ar…
The isothermal phase changes and associated structural features of a long period superstructure of Cu3Au II in a Au-55.2 at% Cu-17.4 ag% Ag alloy are studied by means of X-ray powder diffraction and electron microscopy. A characteristic long period antiphase boundary structure of the Cu3Au II is only induced within a…
Second state AgxNbS2 occurs in two different modifications, 6RAgxNbS2 and 4HAgxNbS2, both built of sandwiches, NbS2, with the niobium atoms in trigonal-prismatic coordination by sulfur atoms, and with the gaps between sandwiches NbS2 alternately empty and occupied by silver. 6R-AgxNbS2 (0.22 ≦ x ≦ 0.30) of which the…
The microstructure of a rapidly solidified Mn4Si alloy is studied by electron diffraction and high resolution lattice imaging. A new two-dimensional octagonal quasicrystal is found together with 45° microdomains of ß-Mn, similar to the case of CrNiSi and VNiSi reported earlier. In addition, an ordered Mn3Si and a…
We present the results of Monte Carlo simulations of jump rates for diffusion (\ensuremath{\Gamma}) in a Lennard-Jones solid under an externally applied nonhydrostatic stress. The particular diffusion event considered is the interchange of a vacancy and an atom. The associated hopping time is calculated within transit…
[Mn(C 3 H 4 N 2 ) 6 ](ClO 4 ) 2 cristallise dans le systeme rhomboedrique avec le groupe d'espace P3. [MnCl 2 (C 3 H 4 N 2 ) 4 ] cristallise dans le systeme monoclinique avec le groupe d'espace C2/c. Affinement de la structure jusqu'a 0,050 et 0,036 respectivement
Defect clusters in semiconductors may cause persistent photoconductivity. A model is developed based on the spatial separation of the photogenerated carriers by the local potential barriers of the clusters. The buildup and decay of the defect-cluster-induced persistent photoconductivity depend on the geometry of the c…
Les deux composes du titre cristallisent dans le systeme orthorhombique avec le groupe d'espace Pnma. Affinement de la structure jusqu'a 0,020 pour les deux composes. Les anions sont des octaedres deformes
Magnetization measurement, 55 Mn NMR and 1 H NMR measurements were performed in hydrides of pseudobinary intermetallics Y(Mn 1- x T x ) 2 (T=Al, Co and Ni); x =0∼0.15). The magnetization measurement indicates that Y(Mn 1- x T x ) 2 H y with y ≦3.5 exhibit ferromagnetism with Mn moments ranging from 0.07 to 0.32 µ B an…
The luminescence properties of Cs2 NaGdCl6 are reported. In the emission, as well as the excitation spectra of the Gd3+ luminescence, vibronic lines are present due to coupling with the ν3 , ν4, and ν6 vibrational modes of the GdCl3−6 octahedron. The magnetic–dipole character of the zero-phonon transitions is confirme…
The resonance and the relaxational dielectric dispersions of KH 2 PO 4 found in the ferroelectric phase were examined for ordinary and lossy specimens. The magnitudes of these two dispersions decreased markedly with crystal defects as well as with a d.c. bias field. A universal relation between the free dielectric con…
Commensurate-incommensurate (C-IC) phase transition of Rb 2 ZnCl 4 is studied by low temperature transmission electron microscopy. Nucleation and disappearance of pairs of “dislocations” composed of six discommensurations (DCs) and their motions along the c plane play an important role in the transition prcccess. Duri…
The characteristics of luminescence observed during the initiation of an electrical tree have been studied for polyethylene subjected to high electrical stresses. Use of a light detection system which is at least three orders-of-magnitude more sensitive than conventional partial discharge detectors shows that luminesc…