Materials Literature
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The kinetics of forward and backward energy transfer processes in fluoroindate glasses double doped with Yb3+ and Er3+ has been studied. It was possible to excite selectively Yb3+ ions and detect emission due only to these ions or combined with the emission coming from the Er3+ ions. At low concentration of Yb3+ (0.1…
Ethylene and linear, nonconjugated dienes were copolymerized with the catalyst system Cp2ZrCl2/methylaluminoxane (MAO). The comonomer incorporation and the relationships between structure and properties were evaluated by NMR and by thermal techniques, especially the segregation fractionation technique (SFT) using DSC…
Atomic and electronic structures of intrinsic point defects in yttrium oxysulfides $({\mathrm{Y}}_{2}{\mathrm{O}}_{2}\mathrm{S})$ are studied by first-principles total-energy calculations based on density-functional theory combined with normconserving pseudopotentials. Energetics of all the intrinsic point defects are…
The effect of ion bombardment on the chemical structure and optical properties of polyimide films was investigated. Oxygen and nitrogen ion beams with energies in the range of 0.5–1.0 keV and doses between 1.7×1015 and 8.2×1016 ions/cm2 were irradiated on the films, and in situ x-ray photoelectron spectroscopy (XPS) a…
Using the method of mapping of a spin problem onto a particle one, we study phase transition between quantum and classical regimes for the escape rate of biaxial spin system in the presence of both a transverse and longitudinal field. It is found that the phase diagram separating the first- from the second-order trans…
A series of novel soluble poly(amide-imide)s were prepared from the diimide-dicarboxylic acid, 2,2-bis[N-(4-carboxyphenyl)-phthalimidyl]hexafluoropropane, with various diamines by the direct polycondensation in N-methyl-2-pyrrolidinone containing CaCl2 using triphenyl phosphite and pyridine as condensing agents. All t…
Without external fields, ferroelectric materials will have multidomain configuration in the ferroelectric state. Detailed analysis found that twinning may not be treated as random since the number of orientations for the domain walls are limited in a given symmetry change during a ferroelectric phase transition. In ea…
Semi-interpenetrating polymer network (semi-IPN) coatings were prepared by using castor oil-based polyurethane (PU) and nitrocellulose (NC) with various viscosity-average molecular weights (Mη) from 6 × 104 to 42 × 104, and coated on a regenerated cellulose (RC) film to obtain water-resistant film. The PU/NC coatings…
Sequential poly(methyl acrylate)/poly(hydroxyethyl acrylate) interpenetrating polymer networks with different poly(hydroxyethyl acrylate) contents were prepared by free radical polymerization of hydroxyethyl acrylate inside the previously polymerized poly(methyl acrylate) network. Differential scanning calorimetry on…
Electron nanodiffraction, particularly as performed in a dedicated STEM instrument with coherent illumination, provides, in principle, a means for obtaining information on structural detail in the range between that of STEM image resolution, about 0.2 nm, and the limits of information possible from elastic scattering…
Because it has been well-known that the effective exchange interaction of spins is much larger within a molecule than between molecules, it is very important to design high-spin polymers linking high-spin molecules with each other as a constituent unit to obtain molecule-based ferromagnetic materials with high transit…
Well-defined α,ω-methacryloyl poly-ε-caprolactone (PCL) and poly(d,l)-lactide P(D,L)LA dimacromonomers have been synthesized by living ring-opening polymerization of the parent monomers initiated by diethylaluminum 2-hydroxyethylmethacrylate (Et2AlO(CH2)2OC(O)C(CH3)CH2) and terminated by reaction of the propagat…
Compatibilization of polystyrene/polypropylene (PS/PP) blends, by use of a series of butadiene–styrene block copolymers was studied by means of small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM). The compatibilizers used differ in molar mass and the number of blocks. It was shown that the a…
The low-temperature fluorescence of single CdS nanocrystals and of single CdS/HgS/CdS quantum well quantum dots (QDQW's) where an atomic monolayer of HgS is embedded in a CdS nanocrystal is compared. The fluorescence spectrum of the CdS nanocrystals depends strongly on the laser excitation intensity. At high excitatio…
Depth-resolved measurements of the photoluminescence of Si implanted and annealed SiO2 films on Si have been performed to determine the depth distribution of luminescent Si nanocrystals. Si nanocrystals with diameters ranging from ∼2 to 5 nm were formed by implantation of 35 keV Si ions into a 110-nm-thick thermally g…
We demonstrate that the half-doped bilayer manganite La_{1}Sr_{2}Mn_{2}O_{7} exhibits CE-type charge-ordered and spin-ordered states below $T_{N, CO}^A = 210$ K and below $T_{N}^{CE} \sim 145$ K, respectively. However, the volume fraction of the CE-type ordering is relatively small, and the system is dominated by the…
The microstructure and domain structures of high performance temperature-compensated sintered magnets with composition of Sm0.56GdxDy0.44−x(TM)7.22 (TM=Co0.68Fe0.22Cu0.08Zr0.02)7.22 (0.0⩽x⩽0.4) have been investigated by using electron microscopy and magnetic force microscopy. Both microstructure and magnetic propertie…
Low-energy electron diffraction intensity vs voltage (LEED I-V) measurements and analysis are used to determine the multilayer surface relaxation of W(110). Measurements and analysis are presented for both flat and vicinal surfaces, demonstrating that surface roughness leads to only small errors in LEED structure dete…
The nature of the interaction between highly oriented pyrolitic graphite (HOPG) and adsorbed Ti is examined by soft x-ray photoelectron spectroscopy. By monitoring the C $1s$ signal, it is found that Ti does not chemically bond to, but only interacts through the Van der Waals force with, a pristine HOPG surface. Time-…
Recent studies with the anthracycline Adriamycin have demonstrated its activation by formaldehyde and subsequent binding to DNA in vitro. Since formaldehyde levels are known to be higher in cells of myeloid origin and the structurally related drug mitoxantrone is most effective against cancers of myeloid origin, this…