Materials Literature
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The Current State of Technology and Potential for Further Development of Magnesium Applications (K. Kainer & F. von Buch).Die-Casting Magnesium (R. Fink).Vacuum Die-Casting of Magnesium Parts with High Pressure (M. Siederslebnen).Squeeze-Casting and Thixo-Casting of Magnesium Alloys (K. Kainer & T. Benzler).Deformatio…
We study the behavior of wave propagation in materials for which not all of the principal elements of the permeability and permittivity tensors have the same sign. We find that a wide variety of effects can be realized in such media, including negative refraction, near-field focusing, and high impedance surface reflec…
Alkyliron(Ⅲ) porphyrins, n-butyliron(Ⅲ) tetraphenylporphyrin, (TPP)Fe-Bu and n-butyliron(Ⅲ) tetrakis-(pentafluorophenyl)porphyrin, <TEX>$(F_{20}TPP)Fe-Bu$</TEX> have been evaluated as suitable for olefin free-radical polymerization. Butyl radicals dissociated from n-butyliron(Ⅲ) porphyrin initiated the polymerization…
Previously determined crystal structures of the zinc enzyme Escherichia coli class II fructose-1,6-bisphosphate aldolase display good agreement for the protein structure but a differing metal-ion organization in the active site. The structure of the enzyme with Cd(2+) in place of Zn(2+) has now been determined to 2.0…
The Ta(6)Br(12)(2+) cluster compound is known to be a powerful reagent for derivatization of crystals of large macromolecules at low resolution. The cluster is a regular octahedron of six Ta atoms with 12 bridging Br atoms at the edges of the octahedron. The cluster is compact, of approximately spherical shape, with a…
The tracing of experimental electron maps in the field of protein crystallography is not a rate-limiting step for structure elucidation, but does represent the process that requires the most expertise and user time. This paper presents a method for automatically tracing the electron-density maps of proteins which can…
Abstract Constitutive equations are derived for the time‐dependent behavior of semicrystalline polymers at isothermal loading with small strains. A semicrystalline polymer at temperatures above the glass‐transition point for its amorphous phase is thought of as a network of macromolecules bridged by junctions (physica…
A new organic–inorganic hybrid material, that shows photoinduced reduction of refractive index as well as volume contraction, has been prepared using a sol–gel method. Whereas previous photosensitive materials show a photoinduced increase in refractive index, this hybrid material shows a significant decrease in refrac…
The interaction of a coadsorbed mixture of acetone and oxygen with a clean oxidized polycrystalline sample of TiO 2 (P25) was investigated using electron paramagnetic resonance (EPR) spectroscopy. UV illumination of the sample at low temperature (100 K) generated an unstable radical intermediate at the dehydrated (and…
Polycrystalline diamond films were synthesized on silicon substrates for the first time without diamond seeding by a very low power (38 W) microwave plasma chemical vapor deposition reaction of a mixture of helium−hydrogen−methane (48.2/48.2/3.6%). The films were characterized by time-of-flight secondary ion mass spec…
Abstract The pyrolysis product distributions of polypropylene (PP) were observed, and the experimental data were semiquantitatively analyzed by computer simulation with the Molic mouse method. Studies by many researchers on PP decomposition and experimental results achieved in this study were examined. The product dis…
Carbon nanotubes (CNTs) are composed of cylindrical graphite sheets consisting of sp(2) carbons. Due to their structure CNTs are considered to be aromatic systems. In this work the number of Kekulé structures (K) in "armchair" CNTs was estimated by using the transfer matrix technique. All Kekulé structures of the cycl…
Abstract Poly(ethylene oxide) with a molecular weight of 2,000,000 was crosslinked by a difunctional peroxide in the molten state. We determined the molecular weight between crosslinks by swelling the samples with deionized water and by indentation and dynamic mechanical analysis. Results were compared with the calcul…
La 1 - x Na x MnO 3+ δ samples with well-defined cation molecularity and oxygen contents ( x = 0.05, x = 0.13, and −0.04 ≤ δ ≤ 0.078) are analyzed with XRPD, electrical conductivity, static magnetization, and EPR measurements. The majority defects induced by oxygen over- and under-stoichiometry are cation and oxygen v…
ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTA Colloidal Templating Method To Hollow Bimetallic NanostructuresLehui Lu, Guoying Sun, Shiquan Xi, Haishui Wang, Hongjie Zhang, Tiedong Wang, and Xiaohuan ZhouView Author Information Laboratory of Physical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of…
Graphite oxide (GO)−birnessite manganese oxide (BirMO) nanocomposite was synthesized via restacking of the GO layers encapsulated with Li−BirMO layers, which precipitated in situ on the surfaces of exfoliated GO sheets. The results suggest that GO and BirMO nanosheets are stacked alternatively with their c-axis aligne…
ITO electrodes modified with a meso,meso-linked porphyrin oligomer have been prepared for the first time to achieve improved light-harvesting efficiency and a larger quantum yield for photocurrent generation as compared to the corresponding porphyrin monomer system. An increase in the number of the porphyrins in meso,…
Abstract Raman and infrared spectra were recorded for A 2 Mn 2 O 7 (A = Y, Dy, Er, Yb) pyrochlores. For the first time, lattice dynamic analysis of cubic manganate pyrochlores was carried out using a short‐range force model with four stretching and four bending force constants at the zone center. The assignment of all…
Hydrothermal technology was used to control the phase behavior and morphology of advanced electroceramics for applications as sensors, piezoelectrics, and low-loss dielectrics in microwave components. Conventional and microwave-assisted hydrothermal syntheses of perovskite-type ceramics NaNbO 3, BaZrO 3, BaHfO 3, BaMg…
Biominerals are formed through an intimate association of inorganic materials and organic macromolecules. As Douglas explains in his Perspective, materials scientists increasingly use these materials as an inspiration for new synthetic materials with superior properties. Model systems can also shed light on the mechan…