Materials Literature
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L-Vinylglycine (L-VG) is both a substrate for and a mechanism-based inhibitor of 1-aminocyclopropane-1-carboxylate (ACC) synthase. The ratio of the rate constants for catalytic conversion to alpha-ketobutyrate and ammonia to inactivation is 500/1. The crystal structure of the covalent adduct of the inactivated enzyme…
A free-volume theory is developed based on the defect diffusion model (DDM). In addition, positronium annihilation lifetime spectroscopy (PALS) ortho-positronium free-volume and intensity data are presented for poly(propylene glycol) with a molecular weight of 4000 (PPG 4000) in both the glassy and liquid states and d…
The mechanism of CO oxidation reaction on oxygen-precovered Pt(111) surfaces has been studied by using time-resolved near-edge x-ray absorption fine structure spectroscopy. The whole reaction process is composed of two distinct paths: (1) a reaction of isolated oxygen atoms with adsorbed CO, and (2) a reaction of isla…
The field-dependent domain structure of a ${\mathrm{La}}_{0.7}{\mathrm{Sr}}_{0.3}{\mathrm{MnO}}_{3}$ thin film epitaxially grown on a ${\mathrm{LaAlO}}_{3}$ (001) substrate has been investigated at low temperatures by magnetic force microscopy. Due to the lattice mismatch, the ferromagnetic thin film is structurally d…
An approach is proposed to theoretically construct a realistic single-crystal GaN nanotube at atomic scale. The generated atomic structures of the single-crystal GaN nanotubes match the structural aspects from experiment very well. Our energetic calculations show that a single-crystal GaN nanotube with [100]-oriented…
X-ray and neutron diffraction techniques are combined with first-principles-based simulations to derive and understand the structural properties of $\mathrm{Pb}(\mathrm{Sc},\mathrm{Nb},\mathrm{Ti}){\mathrm{O}}_{3}$ (PSN-PT) near its morphotropic phase boundary (MPB). An analysis of our measurements yields, at room and…
The thermophysical properties of liquid Te, namely, density, electrical conductivity, and viscosity, were determined using the pycnometric and transient torque methods from the melting point of Te (723 K) to approximately 1150 K. A maximum was observed in the density of liquid Te as the temperature was increased. The…
Under similar test conditions, the electromigration reliability of Al and Cu metallization interconnect trees demonstrates significant differences because of the differences in interconnect architectural schemes. In Cu technology, the low critical stress for void nucleation at the interface of the Cu and the inter-lev…
The electronic properties of Li doped single-wall carbon nanotubes were studied by high-resolution photoemission spectroscopy. Upon Li intercalation, the limited displacement of the Fermi level agrees with a partial charge transfer of the Li2s electron to the $\mathrm{C}2p\text{\ensuremath{-}}{\ensuremath{\pi}}^{*}$ s…
A Raman and photoluminescence study of a thermally annealed free-standing film of silica containing Si nanocrystals is reported. The laser-induced thermal effects are observed, including the increase of the absorption coefficient and the strongly nonlinear rise of the light emission. The light emission measured at hig…
Far-infrared dispersion of the complex dielectric constant in incipient ferroelectric $\mathrm{K}\mathrm{Ta}{\mathrm{O}}_{3}$ has been revealed by terahertz time-domain spectroscopy (THz-TDS) in the temperature range from $8\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ to $300\phantom{\rule{0.3em}{0ex}}\mathrm{K}$. The real…
Utilizing a transient absorption (TA) technique based on a chirp-corrected broadband probe, we have studied the ultrafast photoresponse of dispersed HiPco single-wall carbon nanotubes (SWNTs) over the range of 440--1050 nm for excitation in the range of 430--1700 nm. While both metallic and semiconducting SWNTs show t…
An asymmetrically substituted viologen (V) has been covalently anchored to single wall carbon nanotube (SWNT) through an ester linkage by reacting chlorinated purified SWNT with N-methyl-N'-(6-hydroxyhexyl)-4,4'-bipyridine. Spectroscopic evidence for the covalent bond of viologen in V-SWNT comes from the chemical shif…
The optical properties of silicon nanoparticles were measured in the mid-infrared region (2–20μm). The resulting spectra show effects of light scattering as well as absorption features due to excitations of Si–O and Si–H bonds. We are able to model the obtained spectra using an effective medium approach. The nanoparti…
The surface structures of cubo-octahedral Pt-Mo nanoparticles have been investigated using the Monte Carlo method and modified embedded atom method potentials that we developed for Pt-Mo alloys. The cubo-octahedral Pt-Mo nanoparticles are constructed with disordered fcc configurations, with sizes from 2.5 to 5.0 nm, a…
We investigated the effects of annealing on the rearrangement of H-bonding structure and its influence on the thermal and rheological properties of a fourth-generation hyperbranched polyester polyol based on 2,2-bis(methylol)propionic acid (Boltorn H40). With increasing annealing time and decreasing temperature, the e…
Glass-forming monohydroxy alcohols exhibit two dielectric relaxation signals with super-Arrhenius temperature dependence: a Debye peak and an asymmetrically broadened alpha-process. We explore the behavior of these distinct relaxation features in mixtures of such liquids by dielectric measurements. The study focuses o…
[reaction: see text] Palladium porphyrins are valuable photosensitizers and luminescent agents in biology and materials chemistry. New methodology is described wherein a 1-acyldipyrromethane is converted into the palladium chelate of a trans-A(2)B(2) porphyrin via a one-flask reaction. The reaction entails self-conden…
Magnetization measurements of the wurtzite highly resistive bulk crystals of GaN:Mn, codoped with Mg, are presented. Strong anisotropy of magnetization at low temperatures $(2--10\phantom{\rule{0.3em}{0ex}}\mathrm{K})$ was observed. The data were analyzed assuming Mn ions in ${d}^{4}$ configuration. The crystal field…
Thermal interface materials (TIMs) play a key role in the thermal management of microelectronics by providing a path of low thermal impedance between the heat generating devices and the heat dissipating components (heat spreader/sink). Thermal greases are TIM solutions that are widely utilized in the industry for the…