Materials Literature
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K2NaScF6 crystals codoped with V3+ and Er3+ exhibit some novel cooperative near-IR to visible upconversion processes at cryogenic temperatures. V3+ mainly acts as a broadband sensitizer. The V3+ 3T1g --> 3T2g excitation between 13,500 and 15,500 cm(-1), after fast relaxation to V3+ 1T2g, can be transferred to Er3+ 4I(…
A fundamental kinetic model was constructed from first principles for the hydrogenation of benzene over a Pt(111) catalyst. Benzene adsorbs at the hollow and the bridge sites of the Pt(111) surface. Benzene at the hollow site is the reactive species, whereas benzene at the bridge site is too strongly bound. Hydrogenat…
We propose a Stokes parameter method for determining two-dimensional (2D) cell parameter distributions such as a pretilt angle in addition to the cell thickness and the twist angle of the twisted nematic liquid crystal display (TNLCD) by measuring Stokes parameters at plural wavelengths including a near-infrared regio…
Abstract The crystal structure of i Pr 4 Sn 4 S 6 consists of isolated molecules that contain an adamantane‐like Sn 4 S 6 core. The tin atoms are coordinated nearly tetrahedrally, with Sn–S distances ranging from 2.397(1) to 2.411(1) Å. Copyright © 2004 John Wiley & Sons, Ltd.
The new vanadyl phosphate Na 4 VO(PO 4 ) 2 was synthesized and investigated by X-ray powder and single-crystal diffraction, high-temperature X-ray diffraction, electron diffraction, high-resolution electron microscopy, thermal analysis, magnetic susceptibility, and conductivity measurements. The compound undergoes a r…
Abstract Using oxygen ion implantation and pulsed laser melting, we have synthesized thin films of highly mismatched ternary ( y = 0) and quaternary ( y = 0.12) Zn 1− y Mn y O x Te 1− x alloys with oxygen content in excess of x ∼ 0.01. We show that incorporation of a small amount of isoelectronic oxygen leads to the f…
Carbon nanotubes (CNTs) were grown by low-pressure thermal chemical vapor deposition using pure ethylene. It was found that straight CNTs, which were composed of bundled single- or double-wall CNTs and multiwall CNTs, were preferentially bridged between Fe nanoparticles under a low pressure of 100 Pa. Moreover, utiliz…
Abstract Control of ZnO and CdO crystalline structures and p‐type doping in ZnO were studied. Formation of zincblende ZnO layers as well as zincblende CdO/ZnO short‐period superlattices (SPSL) are demonstrated and bright luminescence was observed even at room temperature from the CdO/ZnO SPSL. p‐Type conductivity obse…
We present a spectrophotometric investigation of the processes in three azobenzene polymers induced by a linearly polarized Ar beam (488 nm). The polymers differ only in the length of the spacers attaching the chromophores to the main chain. The experimental results show that this difference determines not only the po…
Abstract Undoped ZnO layers grown by molecular beam epitaxy (MBE) were investigated aiming at biosensing devices based on organic/inorganic hybrid structures. Clear observation of free exciton emission in low temperature photoluminescence (PL) spectra and electron mobility as high as 114 cm2/Vs at room temperature ind…
Abstract We investigate ZnO epitaxial layers grown by MBE (Molecular Beam Epitaxy) and MOVPE (Metal Organic Vapor Phase Epitaxy) techniques. The samples show similar optical behavior in temperature dependent photoluminescence measurements, reflection and photoluminescence excitation spectroscopy in the low density reg…
Enhanced transmission through subwavelength slit gratings and hole arrays is studied in view of its application in the far-infrared and microwave domains. Because for perfectly conducting gratings, plasmon resonances are not expected to produce an enhanced transmission, other kinds of resonance, such as Fabry-Perot, w…
${\mathrm{BaTiO}}_{3}$ and ${\mathrm{SrTiO}}_{3}$ are ceramic materials having immense technological applications. We present state-of-the-art calculations of the frequency-dependent dielectric function using the full potential linear augmented plane wave method. We find that compared to the previous calculations, our…
Abstract The effects of the size (pseudo‐generation number) and nature of end groups on physical and rheological properties were investigated for a series of hyperbranched polyesters based on an ethoxylated pentaerythritol core and 2,2‐ bis ‐(hydroxymethyl)propionic acid repeat units. The observed linear dependence of…
To lower the dielectric constant k of interlayer-dielectric films with two-dimensional pore structures while maintaining their mechanical strength, the influences of pore arrangement on the elastic modulus E and k of the films were investigated. It was found that periodicity in pore structure enhances E with constant…
Abstract An identification of shallow bound exciton centers in ZnO is presented based on magneto‐optical measurements and diffusion experiments. The thermalization behavior of the Zeeman split components confirms that the I 4 , I 6 , I 8 and I 9 exciton lines stem from donor bound exciton complexes. The results are su…
We report solution-state and solid-state 13 C NMR data for the alanine dipeptide ( N -acetyl- l -alanine- N ‘ -methylamide, AcAlaNHMe) in polycrystalline, lyophilized, and solvated states. Changes in the 13 C chemical shifts of individual carbonyl carbons between the solvated and lyophilized states for the alanine dip…
Abstract A study on the correlation between electrical percolation and viscoelastic percolation for carbon black (CB) and carbon fiber (CF) filled high‐density polyethylene (HDPE) conductive composites was carried out through an examination of the filler concentration (ϕ) dependence of the volume resistivity (ρ) and d…
The basic physical mechanisms by which different kinds of ionizing radiation interact with matter are described. Understanding of these processes, coupled with detailed knowledge of atomic structure, provides much of the foundation for the theory and practice of radiological health protection today.
We performed validation and calibration of the embedded-cluster method in order to study its applicability to modeling defects in amorphous silica, where defect models are not well established. As test systems we used well-studied ${E}_{4}^{\ensuremath{'}}$ and ${E}_{1}^{\ensuremath{'}}$ centers in $\ensuremath{\alpha…