Materials Literature
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The dimension- and size-dependent ground-state properties of ZnO systems are investigated through first-principles density-functional theory calculations. It is found that the effective elastic constants ${C}_{33}$ of polar surface terminated ZnO nanofilms and [0001] oriented ZnO nanowires increase with structural siz…
Discontinuous changes of the lattice parameters at the Mott metal-insulator transition are detected by high-resolution dilatometry on deuterated crystals of the layered organic conductor $\ensuremath{\kappa}\mathrm{\text{\ensuremath{-}}}(\mathrm{BEDT}\mathrm{\text{\ensuremath{-}}}\mathrm{TTF}{)}_{2}\mathrm{Cu}[\mathrm…
Ambipolar carrier conduction has been observed in a metal-insulator-semiconductor field-effect transistor made using (BEDT-TTF)(TCNQ) crystals. The temperature dependence of the source current with the applied positive gate voltage exhibits metal-like behavior at around room temperature. The metal-like conduction tran…
Single-crystalline vanadium oxide nanobelts were obtained through a surfactant-directed growth process under hydrothermal conditions using V 2 O 5 as a precursor. The shape and size were observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). X-ray powder diffraction (XRD), Fourier t…
Simultaneously tracking electronic and molecular structures of a photoexcited metalloporphyrin, present for only 200 ps in a dilute solution, has been realized using X-ray transient absorption spectroscopy (XTA). Using laser pulses as excitation sources and delayed X-ray pulses as probes, we were able to identify the…
Dendronized diblock copolymers are prepared via ring opening metathesis polymerization. Atomic force microscopy imaging of individual molecules clearly establishes the presence of structurally distinct blocks.
A monodisperse, spherical mesoporous silica (Acid-Prepared Mesoporous Spheres, APMS) was prepared and then functionalized with two types of Fmoc (9-fluorenylmethyloxycarbonyl) terminated silanes with variable chain lengths. N2 physisorption experiments indicated that, under some conditions, the pores of the solid were…
Theoretical calculations have predicted that the band gap of boron carbonitride (BCN) nanotubes can be tailored over a wide range by chemical composition rather than by geometrical structure. The following attempts toward the fabrication of BCN nanotube devices should be of great importance both to further understand…
The magnetic and dielectric properties have been investigated for the isostructural oxides of $R{\mathrm{Fe}}_{2}{\mathrm{O}}_{4}$, $R\mathrm{Fe}M{\mathrm{O}}_{4}$, and $R\mathrm{Ga}\mathrm{Cu}{\mathrm{O}}_{4}$ ($R=\mathrm{Yb}$ and Lu, $M=\mathrm{Co}$ and Cu). The magnetization measurements for $R{\mathrm{Fe}}_{2}{\ma…
Designing better cathode materials for solid oxide fuel cells can be aided by quantum-chemical calculations on oxygen reduction on Sr-doped LaMnO3 surfaces (La0.5Sr0.5MnO3=LSM0.5), which show that the reaction (see energy profile [eV]) proceeds via superoxo- (La-super and Mn-super) and peroxo-like (Mn-per) intermediat…
The photochemical conversion of 200-500 nm layers of perhydropolysilazane --(SiH2-NH)n-- (PHPS) in the presence of oxygen into an SiOx network was studied. Different UV sources in the wavelength range of 160-240 nm, that is, 172 nm Xe2* and 222 nm KrCl* excimer, and 185 nm Hg low-pressure (HgLP) lamps were used for th…
The unusual architecture of the enzyme (MsAcT) isolated from Mycobacterium smegmatis forms the mechanistic basis for favoring alcoholysis over hydrolysis in water. Unlike hydrolases that perform alcoholysis only under anhydrous conditions, MsAcT demonstrates alcoholysis in substantially aqueous media and, in the prese…
Supercrystallization of CdS nanorods (10 nm x 25 nm) into perpendicular superlattices was obtained by controlled evaporation of a nanorod solution trapped between a smooth substrate and a block of highly oriented pyrolytic graphite (HOPG). Hexagonal oriented domains 2 microm2 in size were routinely obtained on a varie…
We have synthesized a range of photolabile conjugates of 3,5-dimethoxybenzoin with acetyl salicylic acid, ibuprofen, and ketoprofen. These conjugates can be precisely kinetically controlled to liberate free drug following exposure to 365 nm light for defined periods. Incorporation of the conjugates into limited-porosi…
High Resolution Image Download MS PowerPoint Slide We report vapor-phase synthesis of single-crystalline free-standing Ag nanowires and polarized surface-enhanced Raman scattering (SERS) of a single nanowire, as a first step toward fabrication of well-controlled nanobiosensors employing the SERS technique.
We study the influence of deformations on magnetic ordering in quantum dots doped with magnetic impurities. The reduction of symmetry and the associated deformation from circular to elliptical quantum confinement lead to the formation of piezomagnetic quantum dots. The strength of elliptical deformation can be control…
Using the first-principles spin density functional approach, we have studied magnetism of a new type of all-carbon nanomaterials, i.e., the carbon nanowires inserted into the single-walled carbon nanotubes. It is found that if the 1D carbon nanowire density is not too higher, the ferromagnetic ground state will be mor…
Significant nanoscale disorder of Cu and Ca atomic substitution is observed in CaCu(3)Ti(4)O(12), based on our integrated study using quantitative electron diffraction and extended x-ray absorption fine structure. Unambiguous identification of this previously omitted disorder is made possible by the unique sensitivity…
We report the successful passivation of the Mn acceptors in GaMnP upon exposure to a remote dc hydrogen plasma. The as-grown films are non-metallic and ferromagnetic with a Curie temperature of T_C=55K. After hydrogenation the sample resistivity increases by approximately three orders of magnitude at room temperature…
We present a segregated strain model that can describe the thickness-dependent dielectric properties of epitaxial ferroelectric films. Using a phenomenological Landau approach, we present results for two specific materials, making comparison with experiment and with first-principles calculations whenever possible. We…