Materials Literature
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Selective-area growth has been utilized to deposit chromium dioxide (CrO2) films in specific regions of a prepatterned surface using atmospheric pressure chemical vapor deposition from CrO3 precursor. For films deposited on single crystal TiO2 substrates covered with patterned SiO2 thin film, epitaxial growth occurs s…
The three-dimensional Schrödinger and Poisson’s equations are used to calculate the conduction band profile, energy levels, and Fermi energy of negatively charged semiconductor quantum dots. The calculation is carried out self-consistently within the frame of the finite-difference method. Assuming the effective mass o…
Infrared reflection-absorption spectroscopy and density functional theory, within the generalized gradient approximation, were used to investigate both experimentally and theoretically N2 chemisorption on stepped and smooth Pt surfaces. N2 chemisorption was observed to occur only on the edge atoms of step defect sites…
By heating a pressed tablet of graphite powder mixed with nickel in a quartz tube mounted inside a high-temperature tube furnace at 1200 °C, amorphous carbon nanowires were formed on the inner wall of the quartz tube near a copper cooling finger. Bright-field images of transmission electron microscopy show that the di…
We have developed a method to assemble single-wall carbon nanotube (SWNT) circuits using a tapping mode atomic force microscope. Nanotubes can be controllably translated, rotated, cut, and placed on top of one another by varying the tip–sample force, and the tip speed. These operations let us construct complex nanotub…
We report experimental observations on the ordered surface patterns resulting from the crystallization of annealed thin films of microphase-separated low-molecular-weight hydrogenated poly(butadiene- $b$-ethyleneoxide) diblock copolymers. For crystal growth rates higher than about 1 nm $/$sec the resulting orientation…
The low-cycle fatigue of a TiNi shape memory alloy was investigated by the rotating-bending fatigue tests in air, in water and in silicone oil. (1) The influence of corrosion fatigue in water does not appear in the region of low-cycle fatigue. (2) The temperature rise measured through an infrared thermograph during th…
We study analytically one-dimensional interacting spinless fermions in a Fibonacci potential. We show that the effects of the quasiperiodic modulation are intermediate between those of a commensurate potential and a disordered one. The system exhibits a metal-insulator transition whose position depends both on the str…
We investigate the response of multiwalled carbon nanotubes to mechanical strain applied with an atomic force microscope probe. We find in some samples, changes in the contact resistance dominate the measured resistance change. In others, strain large enough to fracture the tube can be applied without a significant ch…
The effective interaction energy of a colloidal sphere in a suspension containing small amounts of nonionic polymers and a flat glass surface has been measured and calculated using total internal reflection microscopy and a novel approach within density functional theory, respectively. Quantitative agreement between e…
Ternary $({\mathrm{Ge}}_{x}{\mathrm{Se}}_{1\ensuremath{-}x}{)}_{1\ensuremath{-}y}{\mathrm{Ag}}_{y}$ bulk glasses in the Se-rich region $(x<\frac{1}{3})$ are shown to be intrinsically phase separated into an ${\mathrm{Ag}}_{2}\mathrm{Se}$-rich glass and a residual ${\mathrm{Ge}}_{t}{\mathrm{Se}}_{1\ensuremath{-}t}$…
A giant magnetic-field-induced strain (MFIS) of −3100 ppm has been obtained in Heusler alloy Ni52Mn22.2Ga25.8 single crystal in the [001] direction at a temperature from 23 to 31 °C. This MFIS reaches saturation in an applied field about 6 kOe, and exhibits the same amplitude with an opposite sign while the field is p…
Silicon carbide (SiC) nanowires on a silicon substrate were prepared using hot-filament-assisted chemical-vapor deposition with a solid silicon and carbon source. The SiC nanowires show good field-emitting properties as revealed by the current–voltage characteristics. Together with its ease of preparation, these SiC n…
We have investigated the diffuse phase transition accompanying the formation of submicrometric ferromagnetic-metallic (FM) domains embedded in the antiferromagnetic charge-ordered state in ${\mathrm{Nd}}_{1/2}{\mathrm{Ca}}_{1/2}{\mathrm{MnO}}_{3}$ crystals, which is caused by quenched random field originating from Cr…
The linear viscoelastic and diffusional properties of colloidal model dispersions are investigated and possible relations between the (dynamic) shear viscosity and various diffusion coefficients are analyzed. Results are presented for hard sphere and charge-stabilized dispersions with long-range screened Coulomb inter…
The interplay between inter- and intrachain charge transport in bulk polythiophene in the hopping regime has been clarified by studying the conductivity $\ensuremath{\sigma}$ as a function of frequency $\ensuremath{\omega}/2\ensuremath{\pi}$ (up to 3 THz), temperature $T$, and doping level $c$. We present a model whic…
We demonstrate long-term field emission stability from single-walled carbon nanotubes. Unballasted nanotubes operate without degradation for over 350 h at 10−9 Torr. Nanotubes are shown to be significantly less sensitive to operating environments than metallic emitters. In 10−7 Torr of H2O, we demonstrate 100 h of con…
Gold nanoshells, nanoparticles consisting of a silica core coated with a thin gold shell, exhibit a strong optical resonance that depends sensitively on their core radius and shell thickness. Gold nanoshells have been fabricated with a peak optical extinction that can be varied across the near-infrared region of the s…
A new self-designed mechanochemical reactor, inlaid pan-mill, was used in studying high density polyethylene (HDPE) and calcium carbonate (CaCO3) blends. The effects of CaCO3 on the crushing and structure of HDPE matrix and the properties of HDPE/CaCO3 blends were investigated. Scanning electron microscopy, Fourier tr…
The graft copolymerization of methyl methacrylate upon gelatin was studied using benzoyl peroxide as an organic initiator in aqueous medium. The grafting reactions were carried out within the 65–90°C temperature range, and the effect of monomer and initiator concentrations on the graft yield were also investigated. Th…