Materials Literature
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We have investigated the magnetoresistance of graphite in fields of up to 55 T over the temperature range 1--10 K and obtained clear indications of a reentrant transition from the field-induced density-wave state to the normal state. The reentrant transition is attributed to a Landau subband crossing the Fermi level.…
Atomic-resolution $Z$-contrast images provide direct images of chemical disorder and columnar vacancies in an ideal Al-Ni-Co decagonal quasicrystal. Chemical disorder occurs in the central ring of the 2 nm clusters and involves both Al and Ni(Co) atoms. Columnar vacancies are observed in the form of closely spaced, ha…
thin films prepared by pulsed-laser ablation have been investigated by high-resolution x-ray diffraction, x-ray pole-figure, Rutherford backscattering/channelling and electrical measurements. The results show that films deposited on (0001) sapphire substrates grow with well determined orientations in the plane: and ou…
We report the activation field characteristics of (La,Sr)CoO3/Pb(Nb,Zr,Ti)O3/(La,Sr)CoO3 capacitors with areas varying from 13 to 9600 μm2. Switching properties such as maximum current and switching time depend on the capacitor area and measuring circuit elements, but the activation field is independent of capacitor a…
For the perovskites that show colossal-magnetoresistance (CMR) behaviour, we use the global instability index, R1 , as a measure of the influence of the static lattice effects on the magnetic and electrical properties. These effects arise from the size mismatch between the ions at A and Mn sites as well as the size di…
The origin of the relative stability of the cubic, tetragonal, and monoclinic phases of zirconia $(\mathrm{ZrO}{}_{2})$ is investigated. To obtain accurate energies we adopt a new all-electron bandstructure approach within the local density approximation, based on muffin tin orbitals. We also develop a self-consistent…
Single-walled carbon nanotube (SWNT) tips have been used to image nanostructures with high resolution. Studies of gold nanocrystal standards showed that SWNT tips provide a significant improvement in lateral resolution with respect to multi-walled nanotube tips and microfabricated Si tips. The nanotube tips were also…
Graphite nanofibers were synthesized and their hydrogen desorption and adsorption properties are reported for 77 and 300 K. Catalysts were made by several different methods including chemical routes, mechanical alloying, and gas condensation. The nanofibers were grown by passing ethylene and H2 gases over the catalyst…
We study the resonant transmission of light through Fibonacci dielectric multilayers (FDM). Making use of a transfer matrix renormalization technique [E. Maciá and F. Domı́nguez-Adame, Phys. Rev. Lett. 76, 2957 (1996)] we obtain closed analytical expressions for the transmission coefficient under arbitrary incidence a…
Zero-field electrical resistivity over the temperature range of 4–300 K and magnetoresistance in magnetic fields of up to 12 T have been measured in Gd5(Si1.8Ge2.2). This system undergoes a first-order magnetostructural transition at TC≅240 K, from a high-temperature paramagnetic to a low-temperature ferromagnetic pha…
The swelling and viscoelastic behaviors of samples of purified arterial elastin were investigated to develop a model for studying the viscoelastic behavior of elastin. Two osmotic stress models were used: the vapor phase model (VPM), in which the stress on the elastin sample was applied through the vapor phase by equi…
The handedness or chirality of molecules, organisms, and elementary particles has been widely appreciated, vindicating Pasteur’s perceptive generalization, Luni-vers est dissymktrique. Ambidexterity is rare not only in biological organisms but also in molecules. One of the most striking chiral features in biopolymers…
Exact quantum molecular overlaplike and Coulomb-like self-similarity measures are studied in a selected series of molecules with the same number of electrons. It is found that quantum molecular overlap self-similarity measures can be used to estimate the concentration of electronic charge in molecules. A good linear r…
High-quality yttrium oxide thin films can be prepared from [Y(thd) 3 ] ( 1, thd = 2,2,6,6-tetramethyl-3,5-heptanedionato) under mild conditions by the catalyst-enhanced chemical vapor deposition technique using oxygen as carrier gas. Several palladium compounds, such as [Pd(acac) 2 ] (acac = 2,4-pentadionato), [Pd(η 3…
The permittivity ε′ and dielectric loss ε" for different ratios of an ethylene propylene diene monomer (EPDM)–chloroprene rubber (CR) blend ranging from 0 to 100 phr were measured over a frequency range from 400 Hz to 60 kHz. The measurements were carried out at room temperature (25°C). The values of ε′ and ε" were fo…
Oxazoline functionalized polypropylene, polyethylene, ethylene propylene copolymer (E/P), and styrene ethylene/butylene styrene copolymer (SEBS) were studied as compatibilizers in blends of polyolefins with polyesters and polyamides. The blends investigated were polypropylene/polyamide 6, polypropylene/polybutylene te…
A study of nonequilibrium melting, nonisothermal, and isothermal crystallization behavior of ethylene/1-octene (EO) random copolymers, produced using metallocene catalysts has carried out. As branch (or defect) content increases, the nonisothermal and isothermal crystallization rates, melting temperatures, and heats o…
Engineering tissues utilizing biodegradable polymer matrices is a promising approach to the treatment of a number of diseases. However, processing techniques utilized to fabricate these matrices typically involve organic solvents and/or high temperatures. Here we describe a process for fabricating matrices without the…
2-(6-Oxido-6H-dibenz 〈c,e〉〈1,2〉 oxaphosphorin-6-yl) dimethyl itaconate (ODOP-DI) was prepared by the addition reaction between 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and dimethyl itaconate while DOPO was synthesized through multistep reaction from o-phenylphenol and phosphorus trichloride. The compo…
A series of trifunctional epoxy resins were successfully synthesized by the condensation of 2,6-dimethylol-4-methylphenol with phenol , cresol, 2,6-dimethylphenol or 2-naphthol, respectively, followed by epoxidation with a halohydrin. The structures of the synthesized triphenols were characterized by elemental analysi…