Materials Literature
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Scanning tunneling microscopy and scanning tunneling spectroscopy (STS) are used to study the structural and electronic properties of bilayer epitaxial graphene on SiC(0001). Topographic images reveal that graphene conforms to the SiC interface morphology and is observed to be continuous across steps separating adjoin…
We present a theory of momentum-space local density of states (LDOS) maps $N(\mathbit{q},\ensuremath{\omega})$ in graphene. The LDOS map has both intravalley contributions centered near zero momentum and reciprocal-lattice vectors and intervalley contributions displaced by the wave vector ${\mathbit{K}}^{\ensuremath{'…
The authors report a depth-resolved cathodoluminescence spectroscopy study of defects and their distributions in SrTiO3 single crystals and epilayers. In SrTiO3 single crystals, the dominant defects are oxygen vacancies that locate mainly near the free surface, while Ti interstitials locate further into the bulk. Vacu…
A judicious change in the selected transition used for circular polarization excitation will overcome the low oscillator strength limitation of the currently allowed magnetic-dipole (5)D1 <-- (7)F2 (Eu(III)) transition chosen for circularly polarized luminescence (CPL) measurement. The proposed allowed magnetic-dipole…
Extensive ab initio LDA and LSDA + U calculations of an electronic structure of newly discovered high-temperature superconducting series ReO1 − x F x FeAs (Re = La, Ce, Pr, Nd, and Sm and the hypothetical case of Re = Y) have been performed. In all cases, almost identical electronic spectrum (both energy dispersions a…
The effect of hydrogen and helium on the physicochemical properties of ferritic steel has been investigated. Nondestructive testing was used: acoustic methods, nanoindentation, and the eddy-current method. A nonlinear dependence of the nanoindentation parameters and acoustic emission signals on the helium implantation…
We have studied the effects of neutron irradiation (fluences from 5 × 10 15 to 5 × 10 19 cm −2 ) and thermal annealing on the optical spectra of sapphire crystals and the generation and annealing of visible luminescence and absorption centers in the crystals. The radiation-induced color centers with λ = 460, 570, 620,…
Abstract The morphology of ultra nanocrystalline diamond (UNCD) films is modeled by a pure geometrical approach. Diamond spheres with a fixed radius are added randomly spread on a smooth substrate surface covered with diamond seeds in varied primary nucleation density. The secondary nucleation rate and the nucleation…
Unmodified or chemically modified montmorillonite (MMT) dispersed in water was added into the reaction mixture forming hybrid organic–inorganic (O–I) nanocomposite coating. Two basic systems made from functionalised trialkoxysilane and oligomeric diamine v. functionalised dialkoxysilane and triamine were prepared and…
A correlation between melting points and Grüneisen lattice constants was found for a number of glass-forming oxides. It was established that, at the melting point, the mean energy of the thermal motion of a kinetic unit equaled the ultimate strain work of the interatomic bond corresponding to the quasi-elastic force m…
To improve the stability of fine copper powder, it was pretreated by benzotriazole first. Then ammonium persulfate was dripped into treated powder/aniline suspension to produce polyaniline/copper composite. Detected by field emission scanning electron microscope, transmission electron microscope, X-ray diffractometer…
Abstract The foam index test can be useful for predicting air-entraining admixture (AEA) dosage in concrete or for evaluating AEA interaction with other mixture ingredients. The test is sensitive to several factors including total water content, water-cementitious materials ratio, ash-cementitious materials ratio, and…
A modal solution for the problem of scattering by multi-wall carbon nanotubes was developed using an effective-boundary condition approach. The solution can be used to study the electrodynamics of arbitrary carbon nanotube structures with any source excitation. A numerical example of simple MWCNT was given and compare…
The information of band structure of silicon nanocrystal (nc-Si) embedded in SiO2 thin films synthesized by Si ion implantation and subsequent thermal annealing at various temperatures has been obtained from spectroscopy ellipsometric (SE) analysis. The indirect band structure and the energy gap of the nc-Si are not a…
Six nine purity graphite and single-walled carbon nanotube (SWCNT), double-walled carbon nanotube (DWCNT), multiple-walled carbon nanotube (MWCNT) are mass analyzed by the scanning atom probe. Surface atoms well exposed to the external field are field evaporated and individual evaporated fragment ions are detected. Ea…
In article the new construction of the multiple-unit piezoelectric transducer with the increased output power and a disk radiator, which has a refined thermal mode is offered. The designing procedure of bending vibration disk radiators is described. The developed constructions are implemented; their technical characte…
Abstract Crystals of thallium dihydrogendiphosphate Tl 2 Me (H 2 P 2 O 7 ) 2 · 2 H 2 O ( Me = Mg (1) , Mn (2), Co (3) , Ni (4) and Zn (5) ), have been synthesized and analyzed by powder X-ray diffractometry (Mg phase) and single crystal X-ray diffractometry (other phases). They resulted to be isostructural within tric…
The adsorption of CO on polycrystalline ZnO powder samples was investigated as a function of the pretreatment by applying static adsorption microcalorimetry and temperature-programmed desorption (TPD). Mainly weak adsorption sites were found to be present on the exposed ZnO surfaces but also a minor amount of highly a…
The influence of electrothermal feedback and hysteresis on the operation conditions, noise, and performance of a VO2 transition-edge microbolometer has been evaluated. The material undergoes a first-order semiconductor-to-metal phase transition (SMT) within the temperature range 40<T<70 °C. Due to electrothermal feedb…
On the basis of the RF characteristics of p-type diamond field-effect transistors (FETs) with hydrogen surface termination, we establish an equivalent circuit (EQC) model. From comparisons of three cases we reveal that to represent the device performance in the EQC, the source, gate, and drain resistance should be con…