Materials Literature
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Manitoba Hydro applied directional couplers for on-line partial discharge measurements on selected rotating machines beginning in 1981. With the instrumentation available at that time the measurement was vulnerable to the effects of noise external to the machine. There have been improvements in the available coupling…
Traditionally, the blending composition of a composite yams has been analyzed by human visual inspection, but such a method is time-consuming and inaccurate. In this study, we apply image processing techniques to analyzing cross sections of a PET/ Rayon composite yam, obtaining single fiber positions in the image with…
We have performed both conventional canonical molecular dynamics (MD) and multicanonical MD (MMD) simulations for a single di-block polyampholyte in vacuum to investigate possible structural phase transitions. The conventional canonical MD simulation for temperature T∗ > 0.05 gives reliable results, since these are in…
We investigated the dielectric properties of a new type of polyethylene (PE) polymerized with a single-site catalyst. The new PE has much higher dielectric strength and volume resistivity than both conventional low-density PE and linear low-density PE. The increase in the density is considered to be responsible for th…
An encapsulating layer was deposited on the surface of tetragonal zirconia polycrystals doped with 3 mol% of yttria (3Y‐TZP), to prevent low‐temperature environmental degradation (aging) of the material. The layer, which was composed of silica and zircon, was formed on the surface by exposing the specimens next to a b…
First-principles molecular orbital calculations for ZnO with 3 d transition-metal (TM) impurities ranging from Mn to Cu have been carried out in order to investigate the relationship between TM impurities and oxygen adsorption in ZnO ceramics. Two kinds of model calculations, i.e., the TM impurities with various forma…
Abstract We report a “delayed neutralization” process for the preparation of highly‐ordered aluminosilicate MCM‐41 molecular sieves with high thermal and hydrothermal stability, and sharp pore size distribution. However, the structural order and pore size are dependent on the carbon chain length. In the mixture surfac…
The microstructure of a silicon carbide-carbon solid-solution powder (SiC-C), obtained from a fine powder of silicon and thermal expansive graphite, is investigated by X-ray powder diffraction methods. The microstructure is characterized by Williamson-Hall analysis and the strain-field model suggested by van Berkum et…
Abstract The hydrothermal reactivity of a smectite saturated with K was studied experimentally at 300°C and 100 bar in (Na,K) chloride solutions (Na/K = 0, 50 and 100, liquid/solid ratio = 10/1). X-ray diffraction, TEM and microprobe results show: (1) a partial to total dissolution of the initial smectite layers; and…
Hexokinase I governs the rate-limiting step of glycolysis in brain tissue, being inhibited by its product, glucose 6-phosphate, and allosterically relieved of product inhibition by phosphate. On the basis of small-angle X-ray scattering, the wild-type enzyme is a monomer in the presence of glucose and phosphate at pro…
Liposomes are microscopic vesicles composed of phospholipid bilayers surrounding discrete aqueous compartment. Eventhough phospholipid bilayers are formed spontaneously in water, their conventional preparation methods involve either organic solvents or detergent molecules. Organic solvents may create a serious safety…
A new adamantane-based bis(ether anhydride), 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]adamantane dianhydride, was prepared in three steps starting from nitrodisplacement of 4-nitrophthalonitrile with the potassium phenolate of 2,2-bis(4-hydroxyphenyl)adamantane. A series of adamantane-containing poly(ether imide)s were…
Dense TiB ceramics (99.6% of theoretical) with a grain size of ∼5 µm have been fabricated by reaction hot pressing of TiB 2 and titanium for 2 h at 1900°C and 28.5 MPa. The TiB ceramics exhibit a fracture toughness ( K IC ) of 4.5 MPa·m 1/2 and a bending strength (sigma b ) of 360 MPa. Electrical resistivity (rho) is…
The oxidation behavior of reaction‐bonded silicon carbide (RBSC) and the effect of oxidation on the room‐temperature flexural strength of RBSC were investigated. Four different types of RBSC, each having various SiC particle‐size distributions and free silicon contents, were exposed to air at 1300°C for up to 200 h. P…
Chromium carbide thin films are synthesized on Si(100) substrates by a pulsed Nd:YAG laser deposition method at different substrate temperatures. Glancing-angle X-ray diffraction shows that a crystalline chromium carbide film can be prepared at the substrate temperature of 700°C. Grain size of the films, examined with…
A high-pressure Raman study of BaCeO3 was performed at room temperature. This perovskite compound undergoes two phase transitions at about 22 and 28 GPa. The increase in the number of bands is an indication that the symmetry is lowered and that the compound does not evolve towards the ideal cubic perovskite structure…
Structural (X-ray diffraction), melting (differential scanning calorimetry), as well as mechanical (tensile tests) characterizations on uncrosslinked ethene–propene copolymer samples, obtained using a metallocene-based catalytic system and having an ethene content in the range 80–50% by mol, are reported. Samples with…
Reinvestigation of the structural and vibrational properties of the typical perovskite ${\mathrm{KMnF}}_{3},$ exhibiting two antiferrodistortive structural phase transitions, was performed using x-ray powder diffraction and Raman spectroscopy in the range between 30 and 300 K. The x-ray-diffraction work has unambiguou…
A chemical synthesis technique that uses polyacrylic acid (PAA) to prepare nanocrystalline Li 0.3 Zn 0.4 Fe 2.3 O 4 was investigated. Phase‐pure spinel that had an average particle size of ∼13 nm was synthesized at a low temperature (450°C) for 30 min. The average particle size was dependent on the firing temperature…
The effects of phason disorder on the dynamical structure factor of Fibonacci chains are studied, and the existence of a coherent phason field in real quasicrystals is addressed. The neutron-scattering response is modeled for coherent and random phasons. The results show that coherent and random phasons can be disting…