Materials Literature
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Hydrogen-vacancy related defect (H1′) in chemical vapor deposition homoepitaxial diamond films has been investigated by electron paramagnetic resonance and cathodoluminescence. It is found that the concentration of H1′ significantly decreases as the dilution (CH4∕H2) ratio decreases. It is also confirmed that the inte…
Abstract Summary: Polyvinylpyrrolidone (PVP) is a synthetic, non‐toxic, water‐soluble polymer commonly used in a wide range of applications including several pharmaceutical applications. One example of an important application is the controlled release and delivery of therapeutic agents into sites of inflammation or t…
Abstract Graft copolymerization of low‐density polyethylene (LDPE) onto starch was carried out with glucose–cerium(IV) redox initiator in an aqueous sulfuric acid medium under nitrogen atmosphere. The graft yield was influenced by various parameters like reaction time, temperature, and concentrations of acid, glucose,…
An x-ray powder diffraction method was used to study the reaction between carbon nanotubes (CNT) and silicon (Si) nanosize powder at 2 GPa and temperatures varying from 1273 to 1370 K with different sintering times. Samples were obtained using the piston–cylinder system. On the basis of the Avrami–Erofeev model, we fo…
We study a spatial distribution of polyelectrolyte chains and counterions inside nanometer-size capsules by means of molecular dynamics simulation on the level of a colloidal model in which polyelectrolyte coils are modeled as soft charged spheres. The capsule shell is treated as a semipermeable membrane, impermeable…
Abstract The cationic–nonionic dispersing centers with different chain lengths of poly ethylene glycol methyl ether ( N ‐PDEA 750, N ‐PDEA 2000) were prepared from N ‐diethanol amine (NDEA), isophorone diisocyanate (IPDI), and poly(ethylene glycol methyl ether) (PEO M w = 750 and 2000), whereas aqueous cationic–nonion…
Abstract The gas-cooled fast reactor (GFR) is one of six concepts for the Generation-IV nuclear energy system. The fuel for the GFR requires both a high heavy metal loading and the ability to withstand temperatures up to 1600°C during a loss of coolant accident. ZrC is among the few potential refractory ceramic materi…
We demonstrate that a focused CO2 laser beam (λ=10.6μm) can be employed to locally synthesize light emitting defects and Si nanoparticles in silicon rich oxynitride thin films. Films with a stoichiometry of SiO1.08N0.32 were prepared by plasma enhanced chemical vapor deposition with N2O and SiH4. Strongly absorbing CO…
Abstract The polyimide HFPE‐II‐52 was developed at NASA Glenn Research Center for use as a matrix in high temperature composite materials. The unique properties of such composites stem largely from the performance of the matrix at high temperature. Thus, as part of a larger effort to study high temperature composite m…
Abstract The cubic inverse Perovskites (Eu 3 O)In and (Eu 3 O)Sn were prepared from the metals and Eu 2 O 3 or SnO 2 , respectively. For (Eu 3 O)In the crystal structure analysis was performed on single crystal X‐ray diffraction data (space group $Pm{\bar 3}m$ , a = 512.79(3) pm, Z = 1, R gt ( F ) = 0.022, wR ( F 2 )…
Abstract [Ho 5 (H 2 O) 16 (OH) 2 As 6 W 64 O 220 ] 25− , a Large Novel Polyoxoanion from Trivacant Keggin Fragments The novel polyoxotungstate Na 7 K 18 [Ho 5 (H 2 O) 16 (OH) 2 As 6 W 64 O 220 ] · 56 H 2 O ( 1 ) was synthesized in aqueous solution and characterized by X‐ray structure analysis, elemental analysis and I…
Results of low temperature dielectric measurements on the mixed (Ca 1-x Pb x )TiO 3 system are presented to show that a dielectric anomaly appears for x≥0.10.The observed dielectric peak is shown to be due to a thermodynamic phase transition and not due to a relaxor or dipole glass type transition.Curie-Weiss fit to t…
Some intrinsic properties of biomaterials are calculated with atomistic computer simulations through energy minimizations and molecular dynamics methods. The mechanical properties of bulk polymers such as poly(vinyl alcohol) and poly(ethylene terephthalate) are obtained in terms of the Young's modulus, the bulk and sh…
First-principles density functional calculations are employed to study the (001) surface of BaZrO3 with both BaO and ZrO2 termination. Surface structure and band structure have been obtained. For the ZrO2-terminated surface, the large displacement of the O atoms in the first layer results in the small surface rumpling…
X-ray diffraction analysis reveals that the crystallinity of (0001)-oriented columnar grains in ZnO thin films grown on p-Si (100) substrates is enhanced with increasing growth temperature, and transmission electron microscopy confirms that the columnar structures become more stable at higher growth temperature. The m…
Abstract Polyaniline (PANI) hollow microspheres constructed with their own nanofibers were prepared by inversed microemulsion polymerization associated with a template‐free method in the presence of β‐naphthalene sulfonic acid (β‐NSA) as the dopant. The hollow microspheres were 4.0–6.0 μm in outer diameter and 150–250…
Low-energy electronic properties of carbon nanotubes subject to the influences of a transverse electric field and a magnetic field with angle $\ensuremath{\alpha}$ are studied by the tight-binding model. The external fields would modulate energy dispersions, alter energy gaps, destroy state degeneracy, and create addi…
Abstract A polypropylene homopolymer was blended with ethylene–propylene rubber in different mixing ratios. The influence of the ethylene–propylene rubber content on the toughness behavior was investigated. According to the results of instrumented impact tests, brittle‐to‐tough transition temperatures were found for d…
A parametric study was carried out on a novel carbon nanotube (CNT) synthesis using 'arc-discharge in solution' (ADS). The carbon nanostructure yield as a function of time, the rate of erosion of the anode, and the rate of deposition of carbonaceous materials on the cathode electrode were investigated. Amperage depend…
Abstract The mixed powders of poly(ethylene terephthalate) (PET) and SiO 2 has been subjected to cryomilling. The evolution of microstructure with time was characterized using scanning electron microscope, transmission electron microscope, field emission scanning electron microscope, and laser diffraction particle siz…