Materials Literature
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Single crystals of SmFeAsO 1− x F y of a size up to 120 × 100 µm 2 have been grown from NaCl/KCl flux at a pressure of 30 kbar and temperature of 1350–1450 °C using the cubic anvil high-pressure technique. The superconducting transition temperature of the obtained single crystals varies between 45 and 53 K. Obtained c…
Using the shift-operator technique, a compact formula for the Fourier transform of a product of two Slater-type orbitals located on different atomic centers is derived. The result is valid for arbitrary quantum numbers and was found to be numerically stable for a wide range of geometrical parameters and momenta. Detai…
Our x-ray photoemission, magnetization, and transport studies on surface-etched and annealed (Ga,Mn)As epilayers elucidate the key role of the surface oxide in controlling the outdiffusion of self-compensating interstitial Mn impurities. We achieved a dramatic reduction in annealing times necessary to optimize the epi…
Polycrystalline Cu–Al–Mn shape memory alloys (SMAs) with a low degree of order of the β (L2 1 ) phase show excellent ductility and exhibit shape memory (SM) properties such as superelasticity, the one way memory effect and the two way memory effect based on martensitic transformation. These SM properties can be greatl…
This paper presents a comparative analysis of the electromagnetic properties of new composite materials that are of interest to future aircraft/aerospace structures. The fabrication process of single-phase and new multiphase micro/nanocomposites is described. Carbon black, carbon fibers, and multiwall carbon nanotubes…
We present the synthesis and characterization of novel, ultrasmall PbSe magic-sized nanoclusters (MSCs). Unlike the syntheses of high-quality semiconductor nanoparticles, the MSC synthesis is straightforward, occurring at room temperature in air over several hours. MSCs have core diameters <2 nm and fluoresce in the n…
Surface-enhanced Raman scattering (SERS) using novel silver nanorod array substrates has been used for the detection of pathogenic bacteria. The substrate consists of a base layer of 500 nm silver film on a glass slide and a layer of silver nanorod array with a length of approximately 1 microm produced by the oblique…
It is shown that the phase angle of the third harmonic of polarization response (δ3) is very sensitive to the aging state of hard, Fe-doped lead zirconate titanate [Pb(Zr,Ti)O3 or PZT] ceramics and may thus provide rich information on processes responsible for aging in hard ferroelectrics. When hard PZT ceramics exper…
Results of a systematic study are presented to review various effects of crystal size on the martensitic phase transformations in nanocrystalline NiTi shape memory alloys. The transformation temperatures and the transformed volume fraction strongly decrease with decreasing grain size less than about 100 nm. Transforma…
The synthesis of platinum nitride by the laser ablation method is reported. The spectroscopic results show that nitrogen is in interstitial sites of platinum as N-units, contradicting the accepted configuration for PtN2 where it is as N2-units. To elucidate this point we did density functional calculations to correlat…
We study the micromechanics of collagen-I gel with the goal of bridging the gap between theory and experiment in the study of biopolymer networks. Three-dimensional images of fluorescently labeled collagen are obtained by confocal microscopy and the network geometry is extracted using a 3d network skeletonization algo…
Spark plasma sintering (SPS) is a remarkable method for synthesizing and consolidating a large variety of both novel and traditional materials. There are a number of mechanisms proposed to account for the enhanced sintering abilities of the SPS process. Of these mechanisms, the one most commonly put forth and the one…
The morphology of polyaniline nanowires grown electrochemically in anodic aluminum oxide (AAO) templates is strongly influenced by the supporting electrolyte concentration, the potential of electropolymerization, the growth time, and the monomer concentration. Increasing the sulfuric acid concentration during growth i…
We demonstrated a facile synthesis of highly luminescent blue emitting Cd 1− x Zn x S/ZnS core/shell structured nanocrystals (NCs) in straightforward and reproducible manner. The alloyed Cd 1− x Zn x S cores with homogeneity in both size and composition were prepared by introducing S precursors (S dissolved in the non…
The elastic properties of rutile transition metal dioxides XO 2 ( X = Ru , Rh , Os , and Ir ) are investigated using first-principles calculations based on density functional theory. Elastic constants, bulk modulus, shear modulus, and Young's modulus as well as Possion ratio are given. OsO 2 and IrO 2 show strong inco…
We report a systematic first-principles study on the recent discovered superconducting Ba$_{1-x}$K$_x$Fe$_2$As$_2$ systems ($x$ = 0.00, 0.25, 0.50, 0.75, and 1.00). Previous theoretical studies strongly overestimated the magnetic moment on Fe of the parent compound BaFe$_2$As$_2$. Using a negative on-site energy $U$,…
Lead-free ceramics (K0.44+xNa0.52Li0.04)(Nb0.86Ta0.10Sb0.04)O3+x/2 (x=-0,06) were prepared by conventional solid state sintering. The results indicate a correlation between crystalline symmetry and electrical properties. Higher tetragonality was observed in samples with higher piezoelectric response. As the tetragonal…
Based on quantum-kinetic equations, coupled spin-charge drift-diffusion equations are derived for a two-dimensional electron gas on a cylindrical surface. Besides the Rashba and Dresselhaus spin-orbit interaction, the elastic scattering on impurities, and a constant electric field are taken into account. From the solu…
We calculated the image potentials of single-walled carbon nanotubes of various structures with a quantum chemistry method. The image potentials of the single-walled carbon nanotubes can be well fitted with the image potential of an ideal metal sphere of a size comparable to an atom. The image potentials are not sensi…
The thermal decomposition of ammonia borane (AB) in the absence and presence of chemical additives was investigated to develop an approach for reducing the induction period for hydrogen release in the solid state. Gas chromatography techniques were used to measure the yield of hydrogen as a function of time under isot…