Materials Literature
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We show that the electronic and atomic structure of carbon nanotubes undergo dramatic changes with hydrogen chemisorption from first principle calculations. Upon uniform exohydrogenation at half coverage, the cross sections of zigzag nanotubes become literally square or rectangular, and they are metallic with very hig…
We consider a magnet with uniaxial anisotropy in an external magnetic field along the anisotropy direction, but with a field magnitude smaller than the coercive field. There are three representative magnetization configurations corresponding to three extrema of the free energy. The equilibrium and metastable configura…
We describe the design and current performance of the high-flux backscattering spectrometer located at the NIST Center for Neutron Research. The design incorporates several state-of-the-art neutron optical devices to achieve the highest flux on sample possible while maintaining an energy resolution of less than 1mueV.…
Neutron Compton scattering measurements presented here of the momentum distribution of hydrogen in KH2PO4 just above and well below the ferroelectric transition temperature are sufficiently sensitive to show clearly that the proton is coherent over both sites in the high temperature phase, a result that invalidates th…
The effect of disorder on transport and magnetization in ferromagnetic III-V semiconductors, in particular (Ga,Mn)As, is studied theoretically. We show that Coulomb-induced correlations of the defect positions are crucial for the transport and magnetic properties of these highly compensated materials. We employ Monte…
Nanoscale structure formation in copolymers of polyethylene (PE) and polyhedral oligomeric silsesquioxane (POSS) with norbornene and cyclopentyl side-groups can be controlled through choice of crystallization conditions. Aggregates of both crystalline PE and crystalline POSS are found when crystallized from the melt.…
We present an all-electron implementation of the $\mathrm{GW}$ approximation and apply it to wurtzite ZnO. Eigenfunctions computed in the local-density approximation (LDA) by the full-potential linearized augmented-plane-wave or the linearized muffin-tin-orbital method supply the input for generating the Green functio…
Results of d.c. electric conductivity and Seebeck coefficient measurements for PFN, PFN+Li ceramic samples and PFN single crystals are presented. Marked influence of doping with lithium on the value of electric conductivity, and on the type of electric conductance has been found.
We examined in this work the effect of the inter-grains distributions as well as the scaling of the complex impedance in order to analyze its frequency dependance for composite metal-insulator films. The dependance of the characteristic frequencies on the inter-grain distribution is shown for large sample sizes. The i…
A convenient preparation is reported for a series of functionalized, thiol-stabilized gold particles with subnanometer core diameters ( d CORE = 0.8 ± 0.2 nm). The preparation produces previously inaccessible materials through ligand exchange reactions of a phosphine-stabilized precursor, Au 11 (PPh 3 ) 8 Cl 3, with ω…
Poly(ε-caprolactone)/clay nanocomposites were prepared by in-situ ring-opening polymerization of ε-caprolactone by using dibutyltin dimethoxide as an initiator/catalyst. A nonmodified Na + −montmorillonite and two montmorillonites surface-modified by dimethyl 2-ethylhexyl (hydrogenated tallow alkyl) and methyl bis(2-h…
The short-term interactions of chondrosarcoma cells with polyelectrolyte multilayer films built up by the alternate adsorption of poly(L-lysine) (PLL) and poly(L-glutamic acid) (PGA) was studied in the presence and in the absence of serum. The films and their interaction with serum proteins were first characterized by…
Whereas redox processes resulted from the reactions PhSe−/S8 or PhSe2Ph/S3˙−, mixed anions RSSey− (R = Ph, PhCH2; y = 1–3) were obtained by the slow addition of solid selenium to thiolate ions in N,N-dimethylacetamide. The RS− + n Se reactions, which were investigated by spectroelectrochemistry, led initially (n = 1)…
The luminescence and upconversion properties of 0.8% Ti 2+ -doped NaCl at 15 K are studied as a function of external hydrostatic pressure. Luminescence band maxima shifts are analyzed with a ligand field point charge model, allowing an estimate of the compressibility of the spectroscopically active TiCl 6 4- unit in t…
Deuterium nuclear magnetic resonance (NMR) spectroscopy has been used to investigate the director dynamics in the nematic liquid crystal, 4-pentyl-4′-cyanobiphenyl (5CB), confined between two glass plates and subject to magnetic and electric fields. The nematic cell was held in the NMR probe head so that the electric…
Magnetic oxide superlattices are attractive model systems in which to study coupling and interface effects. After briefly summarizing synthesis and characterization methods, this review describes recent experimental results obtained in investigating epitaxial oxide multilayers comprised primarily of ferromagnetic/para…
The three-dimensional structures of the isoleucine ketimine and the pyridoxamine phosphate forms of human mitochondrial branched chain aminotransferase (hBCATm) have been determined crystallographically at 1.9 A resolution. The hBCATm-catalyzed transamination can be described in molecular terms together with the earli…
In many low-spin (S = 1/2) iron porphyrin derivatives, electron spin resonance (ESR) spectra indicate that one of the d(pi) orbitals of iron, either a d(xz) or d(yz), depending on the axial ligands of the porphyrin complex as well as their orientation, is essentially singly occupied; the unpaired electron is almost co…
Abstract High‐intensity ultrasound was used to initiate the bulk polymerization of methyl methacrylate. The polymerization rate varied with the sonication time, the intensity of the ultrasound, and the initiator concentration of poly (methyl methacrylate) in the monomer. Electron spin resonance (ESR) spectra, obtained…
Abstract A regenerated cellulose film (RC) was coated with a graft‐IPNs coating, which was composed of castor oil‐based polyurethane and 2.8 wt % nitrolignin (NL), to obtain water‐resistant films. The effects of NCO/OH molar ratio and different polyols, such as 1,4‐butanediol (BDO) and trimethanol propane (TMP), on th…