Materials Literature
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Fabrication of C/SiC composites by using the heaterless chemical vapor infiltration (HCVI) technique, which is an improved technology based on the conventional chemical vapor infiltration, is reported for the first time in this paper. In the HCVI process, a gradient temperature field formed in the fiber preform overco…
Characteristics of electric parameters in the microarc oxidation (MAO) process of aluminium alloy at constant voltage were studied by a homemade data collecting system. The experimental results show that (1) the variations of the cathodic and anodic current amplitudes and the effective working current reflect obviousl…
PbS nanocrystals were synthesized directly in the conducting polymer, poly(3-hexylthiophene-2,5-diyl). Transmission electron microscopy shows that the PbS nanocrystals are faceted and relatively uniform in size with a mean size of 10 nm. FFT analysis of the atomic lattice planes observed in TEM and selected area elect…
Results of broadband dielectric spectroscopy (BDS) studies, for a remarkable temperature range $(130\phantom{\rule{0.3em}{0ex}}\mathrm{K})$, in supercooled rodlike liquid crystalline $n$-butylcyanobiphenyl (4CB) are shown. They are supplemented by static nonlinear dielectric effect (NDE) measurements in 4CB and 3CB ($…
Polycrystalline diamond and carbon nanotubes (CNTs) exhibit excellent vacuum field emission properties, characterized by low turn-on voltage and high current density. Their atmospheric field emission and ionization capabilities are reported in this paper. Highly graphitic polycrystalline diamond (HGPD) film was grown…
X-ray powder diffraction and transmission electron microscopy were used to investigate the formation characteristics and stability range of the tetragonal modification of a fluorite-type Bi 2 O 3 −Nb 2 O 5 solid solution. The results showed that this tetragonal, commensurately modulated phase forms through the interme…
The first-principles full-potential augmented plane wave (FLAPW) band calculations were performed for a series of ${T}_{2}{\mathrm{Zn}}_{11}$ ($T=\mathrm{Ni}$, Pd, Co, and Fe) $\ensuremath{\gamma}$ brasses to elucidate the Hume-Rothery electron concentration rule. The pseudogap is found immediately below the Fermi lev…
Two manganese complexes, (py2(NMe)2)MnIICl2 (1) and [(py2(NMe)2)MnIIIF2]+ (2), are here described with the macrocyclic ligand py2(NMe)2 (py2(NMe)2 = N,N'-dimethyl-2,11-diaza[3,3](2,6)pyridinophane). For both, the crystal structure is reported. The UV-visible spectrum of 2 exhibits a very broad near-infrared (NIR) band…
We present extensive x-ray absorption fine structure measurements on La(1-x)Ca(x)MnO(3) as a function of the B field (to 11 T) and Ca concentration, chi(21%-45%). These results reveal local structure changes (associated with polaron formation) that depend only on the magnetization for a given sample, irrespective of w…
We report on the absolute scale measurement of the x-ray diffuse scattering in the ZnMgSc icosahedral quasicrystal and its periodic approximant. Whereas the diffuse scattering in the approximant is purely accounted for by thermal diffuse scattering, an additional signal is observed in the quasicrystal. It is related t…
The dispersion characteristics of organoclay in nanocomposites based on end-functionalized polystyrene (PS) and end-functionalized polystyrene- block -polyisoprene (SI diblock) copolymer were investigated using X-ray diffraction (XRD), transmission electron microscopy (TEM), and oscillatory shear rheometry. For the st…
Blends of poly(2-vinylpyridine), polystyrene, and poly(methyl methacrylate) of four different compositions (2:3:0, 3:2:0, 1:1:0, and 2:2:1 w:w:w) were spin-cast onto periodically (λ = 4 μm) patterned substrate (with two alternating stripes: Au attracting PVP and neutral self-assembled monolayer), and resulting film mo…
Single-crystal MnWO(4) nanofibres with diameters as small as 3-4 nm and length up to 800-1000 nm have been successfully synthesized by a novel surfactant-assisted complexation-precipitation method. X-ray powder diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy…
high spin state (rather than a spin-state transition) can be responsible for the MI transition, in agreement with density-functional calculations (Wu 2003 J. Phys.: Condens. Matter 15 503).
Our ab initio calculations of the hyperfine parameters for negatively charged vacancy-hydrogen and nitrogen-vacancy-hydrogen complexes in diamond compare static defect models and models which account for the quantum tunneling behavior of hydrogen. The static models give rise to hyperfine splittings that are inconsiste…
The spatial cell-material interaction remains vital issue in forming biodegradable scaffolds in Tissue Engineering. In this study, to understand the influence of spatial architecture on cellular behavior, 2D and 3D chitosan scaffolds of 50-190 kD and >310 kD MW were synthesized through air drying and controlled rate f…
Lattice Monte Carlo (MC) simulations in the NVT ensemble together with a coarse-grained model of the block copolymer chains are used to explore the phase diagram of pure and bidisperse diblock copolymer melts as a function of temperature and block volume fraction. In the pure systems, we found that the gyroid phase is…
First-principles calculation and x-ray diffraction simulation methods have been used to explore crystal structures and reaction mechanisms of the intermediate phases involved in dehydriding of LiBH4. LiBH4 was found to dehydride via two sequential steps: first dehydriding through LiBH, followed by the dehydriding of L…
We report on the structural and magnetic properties of newly synthesized Heusler alloys, Ru 2− x Fe x CrSi, which have quite recently been shown to be candidates for ferromagnetic metals with high spin polarization from band structure calculations. Polycrystalline samples of Heusler alloys Ru 2− x Fe x CrSi were prepa…
The binding energy of hydrogen atoms to a (10,0) single-walled boron nitride nanotube (SWBNNT) is calculated at 25%, 50%, 75%, and 100% coverage using the density functional theory. The average binding energy is highest at 50% coverage when the H atoms are adsorbed on the adjacent B and N atoms along the tube axis and…