Materials Literature
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We present a detailed ultrasonic study of the low-temperature nonequilibrium (transitional) phase diagram of ${\mathrm{H}}_{2}\mathrm{O}$ ice in the pressure range 0--1.7 GPa and temperature range 77--200 K. A continuous crossover from the thermodynamically driven $\mathrm{I}h$-II transition to the nonequilibrium scen…
This paper reports the unique influence of added [60]fullerene on the gelation ability of Zn(II) porphyrin appended cholesterols 5a − d . At 5 °C 5a with a (CH 2 ) 2 spacer gelated aromatic hydrocarbons such as benzene, toluene, and p -xylene (2.55 × 10 - 2 mol dm - 3 ), whereas at 20 °C these transparent gels were ch…
Zirconium substituted mesoporous SBA-15 molecular silica with Si/Zr ratios of 10, 20, 40, and 80 have been successfully synthesized at 373 K under microwave-hydrothermal conditions within about 2 h. The degree of framework substitution has been monitored by means of powder X-ray diffraction (XRD), nitrogen adsorption,…
A lamella-forming poly(ethylene oxide)- b -polystyrene (PEO- b -PS) diblock copolymer has been blended with a low molecular weight polystyrene (PS) homopolymer to form a miscible polymer blend. The PEO volume fraction is 0.32, and the order−disorder transition temperature ( T ODT ) of this blend is 175 °C. Therefore,…
Superhard cubic boron-carbonitrides $(c\ensuremath{-}{\mathrm{BC}}_{2}\mathrm{N})$ are studied with the use of the ab initio pseudopotential density functional method. The total energy, lattice constant, bulk and shear moduli, and electronic band structures as well as the electron density of states are calculated for…
A new class of bifunctional periodic mesoporous organosilicas (BPMOs) containing two differently bonded organic moieties in a mesoporous host has been synthesized and characterized. By incorporating bridge-bonded ethylene groups into the walls and terminally bonded vinyl groups protruding into the channel space, both…
We report various many-body theoretical approaches to the nonlinear decay rate and energy loss of charged particles moving in an interacting free electron gas. These include perturbative formulations of the scattering matrix, the self-energy, and the induced electron density. Explicit expressions for these quantities…
Abstract High‐quality Raman spectra were used for the characterization of alumina phases of gibbsite, bayerite, diaspore and boehmite. The Raman spectrum of gibbsite shows four strong, sharp bands at 3617, 3522, 3433 and 3364 cm −1 in the hydroxyl stretching region. The spectrum of bayerite shows seven bands at 3664,…
The room-temperature luminescence of single CdSe/ZnS core−shell quantum dots is investigated by spectrally and temporally resolved confocal microscopy. A large (30 nm) blue shift is observed in the emission wavelength during illumination in air. In nitrogen, no blue shift is observed. The blue shift in air is ascribed…
When asked to explain the importance of the discovery of conducting polymers, I offer two basic answers: They did not (could not?) exist, and they offer a unique combination of properties not available from any other known materials. The first expresses an intellectual challenge; the second expresses a promise for uti…
Abstract Chlorination of gloves has gained popularity as a more permanent method of reducing the inherent tackiness of natural rubber latex compared to using powder as a dusting lubricant. Transmission of proteins in natural rubber latex into the air as a result of using powder on natural rubber latex gloves may cause…
0.2 Pb(Mg 1/3 Nb 2/3 )O 3 –0.8Pb(Zr 0.5 Ti 0.5 )O 3 (0.2PMN–0.8PZT) thin films were deposited on Pt(111)/Ti/SiO2/Si [Pt(111)] and Pt(200)/SiO2/Si [Pt(200)] substrates by a sol–gel method, and the effect of orientation on the piezoelectric and dielectric properties of 0.2PMN–0.8PZT thin films was investigated. The 0.2P…
Abstract A novel diamine, bis‐(3‐aminophenyl)‐4‐(trifluoromethyl)phenyl phosphine oxide (mDA3FPPO), containing phosphine oxide and fluorine moieties was prepared via the Grignard reaction from an intermediate, 4‐(trifluoromethyl)phenyl diphenyl phosphine oxide, that was synthesized from diphenylphosphinic chloride and…
The conducting oxide (Ba,Sr)RuO3 (BSR), which offers an appropriate match in structure with (Ba,Sr)TiO3 (BST), was investigated as an interfacial layer to obtain a high tunability and high dielectric constant in BST films. The (100)-textured BST films deposited onto BSR interfacial layers showed smoother smaller grain…
The local optical density of states (LDOS) in 340-nm-diam ${\mathrm{SiO}}_{2}$ spherical microcavities was calculated and probed experimentally by measuring the luminescence decay rate at 1.54 \ensuremath{\mu}m of erbium ions implanted in the colloids. To separate the effect of nonradiative processes, first the radiat…
We present the results of a theoretical study of a body-centered-tetragonal (BCT) phase of carbon nitride (CN) with 1:1 stoichiometry using a self-consistent-charge density-functional tight-binding method. This CN phase is highly stable and has a small $c/a$ ratio of 0.34 with complicated N and C dimerization along th…
As a possible atomic coordination of erbium dopants surrounded by oxygen, a molecular orbital calculation of an ErO6 cluster can predict a C4v pseudo-octahedral structure with Er distortion of ∼0.1 Å from the octahedral center. It was found that bond alternation by a “rack and pinion effect” can minimize the electron…
Abstract The water diffusion behaviors and activation energies of PDA‐ and ODA‐based polyimide thin films were quite dependent on both the chemical structure and the morphological structure in the films. The water diffusion coefficients of polyimide thin films increased with increasing temperature. The activation ener…
The current-induced emission degradation of a carbon nanotube (CNT) thin-film electron emitter is studied under constant emission current for different current levels, using a scanning anode field emission microscope. A permanent emission degradation is observed for emission currents higher than 300 nA per CNT and is…
We present a computer simulation of strain effects on the electronic spectrum of 100 Å diam Si nanocrystal (nc-Si) quantum dots embedded in SiO2, based on the continuum strain model and deformation potential theory. We show that the coupling between the nc-Si geometry and the symmetry generated by the strain potential…