Materials Literature
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Infrared spectroscopy has been calibrated to provide a precise and accurate method for determining the concentrations of molecular water and hydroxyl groups in hydrous albitic glasses. At total water contents less than 4 wt.%, most of the water is dissolved as hydroxyl groups; at higher total water contents, molecular…
Research involving three important interactions of synthetic cationic porphyrins with nucleic acids: DNA binding, oxidative-reductive strand scission and photosensitized strand scission, is examined retrospectively. The observation that these porphyrins as a class can associate with DNA by intercalative binding, outsi…
The effective desorption kinetic parameters of CO on the Pd(111) surface have been studied by thermal desorption spectroscopy. The zero coverage effective desorption activation energy and the preexponential factor were found to be 35.5 kcal/mol and 1013.5 s−1, respectively. As a function of CO coverage, a four-stage c…
In this paper, the effects of modified long ultra-high molecular weight polyethylene (UHMWPE) fibers on the mechanical properties of its rigid polyurethane (RPU) plastic were investigated. The UHMWPE fibers were modified by chromic acid, and the physical and chemical changes of the fiber surface were characterized by…
Piezoelectric properties of polymeric substances arise from either the poling-induced orientation of molecular dipoles (class 1) or the uniaxial orientation of chiral chain molecules (class 2). The class 1 polymers include ferroelectric polymers, polar polymers with frozen-in dipole orientation, and the composites of…
We have prepared glass spherical particles, with one hemisphere hydrophilic, and the other one hydrophobic. These objects, named "Janus beads", may be considered as amphiphilic solids . We have studied the properties of such beads at oil/water interfaces and point out that they do behave differently from ordinary soli…
Using detailed asymptotic analyses of the dynamics of the phase-field model, we show that the major sharp-interface models (Stefan, modified Stefan, Hele-Shaw, etc.) all arise as limiting cases of the phase-field equations. The scaling of the physical parameters in the microscopics leads to distinct macroscopic models…
Kinking of a plane strain crack out of the interface between two dissimilar isotropic elastic solids is analyzed. The focus is on the initiation of kinking and thus the segment of the crack leaving the interface is imagined to be short compared to the segment in the interface. Accordingly, the analysis provides the st…
The superposition model was originally developed to separate the geometrical and physical information in crystal field parameters. Its success in the analysis of lanthanide spectra has been paralleled by the success of the related angular overlap model in the analysis of d-electron spectra. The basic ideas, method of…
The temperature dependence of hypersonic longitudinal and transverse sound waves in ``strong'' (${\mathrm{B}}_{2}$${\mathrm{O}}_{3}$) and ``fragile'' [${\mathrm{Ca}}_{0.4}$${\mathrm{K}}_{0.6}$(${\mathrm{NO}}_{3}$${)}_{4}$] glass-forming systems have been probed using Brillouin scattering. In the latter material the tr…
The hydrogen-bonding status of His57 in the catalytic triad (Asp-His-Ser) of serine protease has important mechanistic implications for this class of enzymes. Recent nitrogen-15 nuclear magnetic resonance (NMR) studies of alpha-lytic protease find His57 and Ser195 to be strongly hydrogen-bonded, a result that conflict…
Methods for the design and synthesis of ligands intended to be specific for a metal ion have been a recent chemical development. This article describes how this process can be inverted so that the specifics of the coordination environment around the metal ion can be used as a template in large-scale ligand synthesis.…
A method of growing high quality 4-(N,N-dimethylamino)-3-acetamidonitrobenzene (DAN) single crystals is presented. Crystal plates with dimensions of up to 10×5×2 mm3 were produced and optically characterized. The transparency region extends from 485 to 2270 nm. Large birefringence and strong dispersion of the refracti…
The electronic structure of fully oxidized polyaniline, pernigraniline, is investigated in the framework of the Su-Schrieffer-Heeger Hamiltonian, making use of an original renormalization technique. Among the family of polyanilines, pernigraniline is the only form to possess a degenerate ground state. It is shown to a…
Giant Shubnikov--de Haas oscillations have been observed in the high-${T}_{c}$ phase (${\ensuremath{\beta}}_{H}$) of an organic conductor \ensuremath{\beta}-(BEDT-TTF${)}_{2}$${\mathrm{I}}_{3}$. The frequency of the oscillations (${H}_{0}$=3730T) Corresponds to about one carrier per unit cell. The extraordinary large…
Alkali-halide single crystals are shown to grow from molecular beams under conditions systematically different from those for metals and elemental semiconductors, for reasons related to ionic bonding. Heteroepitaxy, and the occurrence of epitaxially stabilized new alkali-halide alloys and compounds, are discussed.
Analysis of data from Nd:YAG indicates a substantial experimental divergence from the standard theoretical results predicted for nonradiative energy transfer. A new model for correlated ion placement in the crystal is shown to completely explain the discrepancy.
Single-phase SnxGe1−x alloys with x up to 0.3 have been grown by molecular beam epitaxy. X-ray diffraction measurements indicate the layers to have the diamond crystal structure. The metastability of the alloys is apparent as increases in the growth temperature, layer thickness, or Sn composition cause phase separatio…
We show that a new concept of amphoteric native defects with strongly Fermi level dependent defect formation energy provides the basis for a unified explanation of a large variety of phenomena in semiconductors. Formation of Schottky barriers, particle irradiation induced compensation, doping-induced superlattice inte…
Using the tensor basis and utilising the Wigner-Eckart theorem, the authors obtain the matrix representations (μ00) and (μ10) of O 6 (ST) ⊃ O 3 (S) × O 3 (T). The isoscalar factors of O 6 (ST) × O 6 (ST) ⊃ O 6 (ST) ⊃ O 3 (S) × O 3 (T) are also calculated.