Materials Literature
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Self-assembled silicon nanotubes (SiNTs) are synthesized by a hydrothermal method, with silicon monoxide powder as a starting material and de-ionized water as a reaction medium. No metallic catalysts are added during the process. Unlike the disordered, aggregated SiNTs grown by the template method, the SiNTs synthesiz…
Semiconducting β-SiC nanowires encapsulated in BN nanotubes are prepared using chemical vapor deposition (see Figure). An unusual feature—a gap of 10–15 nm in width between the inner wall of the BN tube and the SiC nanowire—allows various chemical and morphological modifications to be performed on the nanowires.
Electrical spin injection from the Heusler alloy Co2MnGe into a p-i-nAl0.1Ga0.9As∕GaAs light emitting diode is demonstrated. A maximum steady-state spin polarization of approximately 13% at 2 K is measured in two types of heterostructures. The injected spin polarization at 2 K is calculated to be 27% based on a calibr…
The energetics of point defects in oxide materials plays a major role in determining their high-temperature properties, but experimental measurements are difficult, and calculations based on density functional theory (DFT) are not necessarily reliable. We report quantum Monte Carlo (QMC) calculations of the formation…
A simple method for penetrating the barrier layer of an anodic aluminum oxide (AAO) film and for detaching the AAO film from residual Al foil was developed by reversing the bias voltage in situ after the anodization process is completed. With this technique, we have been able to obtain large pieces of free-standing AA…
Three of a kind: Trifunctional nanospheres (TFNs) were constructed by conjugating folic acid to the surface of fluorescent and magnetic bifunctional nanospheres (see microscope images). The TFNs were initially incubated with either normal or cancerous cells to investigate the capture of specific cells. Then, captured…
Polymer-free carbon nanotube fibers are spun from aqueous dispersions using a flocculation-based process that was developed. It produces hollow fibers, folded ribbon fibers, and solid fibers (see Figure). The fibers spun from single-walled nanotubes exhibit relatively high electrical conductivities (∼140 S cm–1 at roo…
Quantum dynamics of a two-state spin system in a rotating magnetic field has been studied. Analytical and numerical results for the transition probability have been obtained along the lines of the Landau-Zener-Stueckelberg theory. The effect of various kinds of noise on the evolution of the system has been analyzed.
The transport properties of diluted magnetic semiconductors (DMS) are calculated using dynamical mean field theory (DMFT) and Boltzmann transport theory. Within DMFT we study the density of states and the dc-resistivity, which are strongly parameter dependent such as temperature, doping, density of the carriers, and t…
Prospect Research on the Diversity of Extracellular Mineralization Process Induced by Mineralizing Microorganisms and Its Use as a Treatment for Soil Pollutants,
We report room-temperature ordered multiphoton emission from multiexciton states of single CdSe(CdZnS) core(-shell) colloidal nanocrystals (NCs) that are synthesized by wet chemical methods. Spectrally and temporally resolved measurements of biexciton and triexciton emission from single NCs are also presented. A simpl…
The synthesis and carrier-transport properties of oligothiophene liquid-crystalline semiconductors are reported. An asymmetrically substituted terthiophene and quaterthiophene give rise to a highly ordered smectic mesophase (see Figure) with an excellent carrier mobility of up to 0.1 cm2 V–1 s–1 over a wide mesophase…
The energy band gap structure and stability of (3,3) and (10,10) nanotubes have been comparatively investigated in the frameworks of the traditional form of the Su-Schrieffer-Heeger (SSH) model and a toy model including the contributions of bonds of different types to the SSH Hamiltonian differently. Both models give…
Molecular mechanics (MM) calculations together with coupling methods bridging MM and finite crystal elasticity are employed to simulate the fracture of defected carbon nanotubes (CNTs) and to compare with the available experimental results. The modified second generation Brenner potential (MTB-G2) is adopted in the ca…
ZnO nanosheets (see Figure) are fabricated by a physical vapor-transport technique. Temperature-dependent microphotoluminescence spectroscopy is conducted from 80–857 K. A surprisingly strong high-temperature (857 K) photon emission is observed. A brief discussion is given in an attempt to understand the physical mech…
Abstract Colloidal nanocrystals are quantum‐size‐effect tunable; offer an abundance of available surface area for electronic and chemical interactions; and are processible from organic or aqueous solution onto substrates rigid or flexible, smooth or rough, flat or curved, inorganic or organic (including biological), c…
Dipolar donor-π-acceptor (D-π-A) compounds have been widely studied in the search for high second-order nonlinear optical (NLO) responses. To that end, most of the structures studied so far make us...
The crystalline structure of two sequential poly(ester amide)s derived from glycine, terephthalic acid, and 1,6-hexanediol or 1,12-dodecanediol has been investigated using X-ray and electron diffraction and real space electron microscopy. Crystal packing shows features of both polyamides and polyesters. The structures…
It has recently been found that alloying with copper improved the inherently poor grindability and wear resistance of titanium. This study characterized the corrosion behavior of cast Ti-6Al-4V alloyed with copper. Alloys (0.9 or 3.5 mass % Cu) were cast with the use of a magnesia-based investment in a centrifugal cas…
The solution form of IIA(Ntr) from Escherichia coli and its interaction with its partner protein, NPr, were characterized by nuclear magnetic resonance (NMR) spectroscopy. The diffusion coefficient of the protein (1.13 x 10(-6) cm/sec) falls between that of HPr (approximately 9 kDa) and the N-terminal domain of E. col…