Materials Literature
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An effort was made toward modifying the Si 3 N 4 ‐SiC phase ratio in bulk nanocomposites obtained from polymer precursors. While pyrolyzing the polymer, flowing ammonia was introduced, to facilitate a chemical exchange, resulting in a different C/N ratio in the ceramic pyrolysis product. A pre‐pyrolysis/binding/pyroly…
Abstract— Almost two‐thirds of the discharge cells in plasma‐display panels (PDPs) are covered with phosphors. Beyond the efficient conversion of vacuum UV photons into visible light, the phosphor layer serves as a reflective mirror transporting light in the desired viewing direction. The quantum efficiency of state‐o…
Submicrometer hollow CuS, CdS, and NiS spheres with diameters between 400 and 1300 nm were successfully prepared through an interface-mineralizing reaction in a NH 3 ·H 2 OCS 2 solution at low temperature. Several techniques were applied to characterize the interesting self-assembled structures. The compositions of t…
A cyano-bridged nickel(II) compound, [NiL][Ni(CN)4]·4H2O (L = 3,10-diethyl-1,3,5,8,10,12-hexaazacyclotetradecane), was prepared and characterized. Single crystal X-ray analysis reveals that the compound assumes a cyano-bridged chain structure in which one nickel(II) ion is coordinated by four cyanide ligands and the o…
The preparation of near stoichiometric spinel and alumina‐rich spinel composites from Al 2 O 3 and MgO powders with the addition of Na 3 AlF 6 up to 4 wt% in the temperature range 700°–1600°C was studied; 98 wt% spinel containing 72 wt% Al 2 O 3 can be produced from the mixture of 72 wt% (50 at.%) Al 2 O 3 + 28 wt% (5…
Dielectric potting materials (encapsulants) are used to prevent air breakdown in high-voltage electrical devices. We report breakdown strengths in void-filled encapsulants, stressed with unipolar voltage pulses of the order of 10 μs duration. High strengths, on the order of 100 kV mm−1, are measured under these test c…
Deformation of shape memory alloys via detwinning of thermally formed martensite twins is a unique microstructural process, which leads to a macroscopic stress plateau in the stress-strain curves. Since this type of deformation mechanism involves insignificantly the dislocation processes, the original shape of the sha…
Wasserfreies Natriummonothiophosphat(V) Na3PO3S wurde auf einem neuen Weg durch Gefriertrocknung des Hydrates und anschließendes Tempern dargestellt. Die Kristallstruktur wurde aus Röntgen- und Neutronenpulverdaten bestimmt. Dabei wurde das Strukturmodell durch kombinierte Optimierung der Differenz zwischen berechnete…
The Auger parameter in vapour-deposited Mg-Ti alloys (Mg-4.2 at.% Ti, Mg-7.6 at.% Ti, Mg-15.1 at.% Ti, Mg-20.7 at.% Ti, Mg-25.3 at. % Ti and Mg-30.2 at.% Ti) has been measured using high-energy X-ray photoelectron spectroscopy with a Cr Kβ (hv = 5946.7 eV) X-ray source. The charge transfer occurring upon alloying was…
A method for the synthesis of 3,4-dihydro-3-pentafluorophenyl-2H-1,3-benzoxazine in a high yield derived from pentafluoroaniline is described. This fluorinated benzoxazine monomer has been developed as a potential precursor for a polybenzoxazine in electronic applications as well as others taking advantage of the low…
An isotactic polypropylene was modified with specific α - phase and β - phase nucleation agents. The modification by processing during extrusion was realised by means of molten state elongation with various stretching ratios λ, between 7.11 and 1.67. The lamellar thickness distribution was evaluated for non-elongated…
o-Nitrobenzyl-protected bioactive compounds are useful tools in biophysics, allowing controlled photorelease of biologically active compounds with high temporal and spatial precision. Thus, it is possible to study biological processes, such as neurotransmitter-receptor interaction, and many other processes, in much mo…
Abstract Phthalocyaninatozinc(II) complexes bearing dendritic substituents have been prepared. It was found that their generation number and positions on the phthalocyanine ring caused unusual absorption and emission spectral features.
Nano-crystalline carbon films possessing a prevailing diamond or a graphite character, depending solely on substrate temperature and deposition time, can be deposited from a methane–hydrogen mixture by the direct current glow discharge plasma chemical vapor deposition method. In this study we investigate the evolution…
As part of a NASA program to develop materials for potential future space applications, poly(arylene ether)s containing phenylphosphine oxide groups were prepared and characterized. The polymers were synthesized by the aromatic nucleophilic displacement reaction of two isomeric bisphenols, 2,5- dihydroxyphenyldiphenyl…
A comparative analysis of the purification methods for single-walled carbon nanotubes (SWNTs) obtained by electric-arc-discharge synthesis is carried out. The purification methods include air oxidation of the initial material at various temperatures, treatment and/or oxidation in solutions of inorganic acids, microfil…
ABSTRACT The relationship between microstructure and nucleation of fatigue cracks in PH 13‐8 Mo stainless steel was explored with the use of atomic force microscopy (AFM) that allowed an accurate quantitative characterization of the surface features. Fully reversed strain‐ controlled fatigue tests were performed at 0.…
In recent papers we have used statistical mechanics to predict multiple phase formation in polymer liquid crystals (PLCs).[1, 2] Now we have performed molecular dynamics simulations of PLC copolymers as materials consisting of LC islands in flexible matrices. A method for creating such materials on a computer is descr…
The 364 nm photoelectron spectrum of Si2C3− is reported, together with high level ab initio calculations of the linear anion, and six linear and eight nonlinear structures of the neutral Si2C3. The adiabatic electron affinity of Si2C3, corresponding to the transition from the linear anion to the lowest electronic stat…
Dyeing of cellulose fibers with reactive disperse dyes is attempted using supercritical carbon dioxide (SC-CO 2 ) as a solvent at 393 K and 20 MPa. For pretreatment, cellulose fibers are treated with tetraethylene glycol dimethylether or N-methyl-2-pyrrolidinone. Results are compared with dyeing with other disperse dy…