Materials Literature
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By employment of the absorbtion of Al3+ and the succeeding coprecipitation on the surface, the nanoscale Y2O3:Eu3+ powders were covered by a layer of composite oxide. Benefitting from the modification of the coating process, the luminescent intensity of nanoscale Y2O3:Eu3+ was improved.
It was confirmed that 313 nm light irradiation of thin films of polymethacrylates with coumarin side chains results in photodimerization without any side reaction. When the light was linearly polarized, the dichroism of coumarin chromophores was generated after prolonged irradiation as a result of axis-selective photo…
The dimpling in the CuO_2 planes of overdoped Y_{1-y}Ca_yBa_2Cu_3 O_{6.96-6.98} (y=0.02-0.2) has been measured by x-ray absorption-fine- structure spectroscopy (Y-K EXAFS). A step-like decrease around 12% Ca indicates a percolation threshold for distorted sites of 5 cells, and thus phase segregation. We conclude the c…
Using N -carbobenzyloxy- l -isoleucylaminooctadecane as a low molecular weight gelator for polar solvents, organogel electrolytes were prepared from supporting electrolyte and a polar solvent such as DMF, DMSO, and PC by physical gelation. The ionic conductivity of the prepared organogel electrolytes decreased very sl…
Domains of ferroelectric Bi4Ti3O12 and ferroelastic NdP5O14 single crystals have been successfully observed for the first time by using a computer-controlled scanning electron acoustic microscope. Signal generation and image contrast mechanisms were discussed.
We derive convenient analytical formulas in the effective-range approximation for the asymptotic coefficient C κ of the radial wave function at infinity and for the average radius of the system. A comparison with the results of numerical calculations (done by the Hartree-Fock method) for multi-electron atoms and ions…
2,4-Dinitrodiphenylamine (DNDPA) has been studied as regards its crystal structure and thermal decomposition characteristics using X-ray diffraction (XRD), simultaneous thermal analysis, ultraviolet and visible spectroscopy, infrared spectroscopy, hot-stage microscopy and high performance liquid chromatography (HPLC).…
Article IRREGULARITIES AND MODULATED DISLOCATION PATTERNS IN PLASTICALLY DEFORMED METALS: THE ECKHAUS INSTABILITY was published on February 1, 1999 in the journal Journal of the Mechanical Behavior of Materials (volume 10, issue 1).
Phenyl substituents in the 6-positions of terpyridine ligands are important for controlling the spin state of their iron(II) complexes. The introduction of phenyl substituents in both the 6- and 6″-positions leads exclusively to the orange high-spin iron(II) complexes, whilst the presence of a single 6-phenyl substitu…
Molecular-crystal precursor states: Molecular dynamics in the nanosecond timescale shows how acetic acid molecules aggregate (see figure for one example) out of a solution in a nonpolar solvent. Is this demixing into a microemulsion the first stage of crystal nucleation?
A new and rapid synthetic method of diaryl carbazone (ArN=NCONHNHAr) from aryl substituted carbazide is reported for the first time. Eight of the compounds were prepared by oxidation of aryl substituted carbazide using N-Bromosuccinimide and pyridine as the oxidation system in good yield under mild condition . This me…
The kinetics equations modified by introducing of the fractional derivatives are used for description of the different dielectric spectra and analysis of the relaxation times temperature dependences. The origin of fractal properties is being discussed in relation with scaling and percolation ideas. The temperature dep…
The properties of porous silicon samples prepared by adding hydrochloric acid to the usual hydrofluoric-acid electrolyte have been studied. These samples exhibit an intense photoluminescence that does not degrade over time and is unaffected by exposure to intense laser illumination. The peak photoluminescence from the…
The influence of the positions of the 1,4-cyclohexenylene fragment and its carbon-carbon double bond in the molecular core, on the mesomorphic behaviour and physical properties of 1,4-disubstituted cyclohexenylene derivatives is discussed and rationalized in terms of existing theories.
Barkhausen pulses generated in stepped motion of a single plane domain boundary (PDB) are investigated experimentally in single-crystalline wafers of the extrinsic ferroelastic ferroelectric gadolinium molybdate containing artificial pinning centers of the “field inhomogeneity” type near the edges of the sample. Two s…
The first part ofthis series discussed current research on yam hairiness testing [Wang 1998]. In this part of the series, the importance of yam hairiness is outlined first. This is followed by a description of recent research on several novel ways of reducing yam hairiness.
Article Type B Semiconductor Photocatalysis: On the Mechanism of the CdS-Catalyzed Linear Photoaddition of 2,5-Dihydrofuran to Azobenzene was published on February 1, 1999 in the journal Zeitschrift für Physikalische Chemie (volume 213, issue 2).
High-frame-rate neutron radiography is used to observe the behavior of a high-temperature (≤773 K) molten Pb-Bi alloy dropped into a vessel that contains water. Experiments are also performed with an empty vessel. Using high-speed cameras combined with image intensifiers and a high-flux neutron source, the interaction…
Based on an original design by F. H. Attix, an improved free-air ionization chamber was constructed at the National Radiation Standard Laboratory of the Institute of Nuclear Energy Research (INER, Taiwan), as the primary standard for x-rays generated at energy levels between 50 keV and 300 keV. Various improvements we…
By means of a sol–gel method, we prepare layered-perovskite samples of La2—2xCa1+2xMn2O7 (x = 0.3) at synthesis temperatures from 1000 to 1200 °C. The grain size changes from 20 to 45 nm. A magnetoresistance above 25% at low temperatures is acquired in a field of 0.8 T. We also find that decreasing grain size is deter…