Materials Literature
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Supramolecular liquid-crystalline polymeric complexes derived from polyamides containing 2,6-bis(amino)pyridyl units in their main chains and benzoic acid derivatives have been obtained by the formation of intermolecular double hydrogen bonds. The polymeric complexes behave as single liquid-crystalline polymers and ex…
Pronounced structure in x-ray excited luminescence (XEL) has been observed in dilute Tb-doped Y2O3 (Y2O3:Tb) nanocrystals. This effect affords a means to assess different energy transfer mechanisms in the nanocrystals and also an opportunity for novel device applications. Sharp jumps and oscillations are found in the…
The vibrational modes of ${\mathrm{H}}_{2}$ molecules in Si are found using a first-principles method and compared with recent experimental investigations. The isolated molecule is found to lie at a ${T}_{d}$ interstitial site, oriented along [011] and is infrared active. The rotational barrier is at least 0.17 eV. Th…
The room-temperature functionalization reaction between poly(styryl)lithium and propylene oxide in benzene was studied. The functionalized polymer was characterized by 1 H NMR, 13 C NMR, and APT- 13 C NMR. 13 C-methyl-labeled propylene oxide-functionalized polystyrene was also synthesized and characterized. Hydroxylat…
A computer-based lattice model of the step growth reaction of an AB2 monomer, the next elaborate system after an AB monomer, has been devised that allows the simultaneous and explicit occurrence of inter- and intramolecular reactions of A and B groups of the flexible and moving molecules according to Monte Carlo selec…
We have measured the magnetization and magnetostriction of Mn 3 GaC in pulsed high magnetic fields up to 37 T and the magnetization under steady magnetic field and pressure up to 0.82 GPa. Mn 3 GaC is antiferromagnetic (AF) at low temperatures. It exhibits successive transitions to an intermediate (I), to a ferromagne…
The synthesis and X-ray structural characterization of two manganese(III) porphyrazine (tetraazaporphyrin) complexes are reported: [Mn(Et 2 dtc)ODMAPz] ( 1 ) and [Mn(Cl)ODMAPz] ( 2 ) (Et 2 dtc = diethyldithiocarbamato; ODMAPz = 2,3,7,8,12,13,17,18-octakis(dimethylamino)porphyrazinato). In both 1 and 2, the Mn(III) ion…
A side-chain liquid crystal (LC) block copolymer with a ferroelectric smectic C* LC block has been shown to exhibit bistable switching behavior in electric fields. Ferroelectric switching was demonstrated for block copolymers with volume fractions of 0.58 and 0.52 liquid crystal block. SAXS and TEM showed that the bul…
Raman scattering, pyroelectric current, and dielectric susceptibility measurements have been carried out on a series of tetragonal and rhombohedral-structured Pb1−xLax(ZryTi1−y)1−x/4O3 (PLZT) ceramics, under zero-field heating after zero-field cooling (ZFH/ZFC) and zero-field heating after field-cooling (ZFH/FC) condi…
The doubly rare-earth doped phosphor SrS:Eu,Sm is representative of a class of stimulable phosphors that may find application in optical data storage and related areas of photonic technology. The infrared photoluminescence (PL) from the ${\mathrm{Sm}}^{2+}$ ions is a potentially useful probe of the ``written'' state o…
The (110) surface of many transition metals undergoes reconstructions either on the clean substrate or induced by adsorbates. The reconstructions can be induced by a variety of strongly bound adsorbates, e.g., H, O, S, and alkali-metal atoms. In this work, H/Pd(110) is chosen as a prototype of such reconstructions. Th…
Steady-state charge transport via motion of charge-density waves (CDW's) requires conversion between collective CDW conduction and quasiparticle conduction in the vicinity of current injection contacts. The conversion occurs via phase slip, in which CDW amplitude defects form and move in the presence of CDW strain so…
Ab initio molecular electronic structure calculations on select silanones, silylenes, and tricoordinated silicon compounds $\mathrm{Si}\mathrm{XYZ}$ with a dangling electron are presented. The calculations are used to evaluate the nature of the electronic spectra, which are to be associated with surface-bound Si/O/H c…
Mixtures of water and poly(vinyl alcohol) (0–96%) have been investigated using molecular dynamics simulations with an atomistically detailed force field. The concentration and temperature (300 and 375 K) dependence of a number of dynamical processes has been studied: Water diffusion including its mechanism, water reor…
In order to understand the radiative recombination mechanisms in silicon oxides, photoluminescence properties (PL) of H-rich amorphous silicon oxide thin films grown in a dual-plasma chemical vapor deposition reactor have been related to a number of stoichiometry and structure characterizations (x-ray photoelectron sp…
Conduction and dielectric behavior of ${\mathrm{Sr}}_{0.97}({\mathrm{Ti}}_{1\ensuremath{-}x}{\mathrm{Fe}}_{x}){\mathrm{O}}_{3\mathrm{\ensuremath{-}}\mathrm{\ensuremath{\delta}}}$ solid solutions were studied. The temperature dependence of the dc conductivity with $\ensuremath{\sigma}\ensuremath{\propto}A\mathrm{exp}(\…
We report on an electroluminescent (EL) diode with novel active layers of silicon (Si) nanocrystallites. The Si nanocrystallite active layer was prepared by pulsed laser ablation in an ambient of reduced pressure inert gas. The structure of the EL diodes was semitransparent platinum (Pt) electrode/Si nanocrystallite l…
Like its homologs throughout the biological world, the L-isoaspartyl protein repair methyltransferase of Escherichia coli, encoded by the pcm gene, can convert abnormal L-isoaspartyl residues in proteins (which form spontaneously from asparaginyl or aspartyl residues) to normal aspartyl residues. Mutations in pcm were…
First-principles calculations based on density functional theory (DFT) and the pseudopotential method have been used to study the adsorption of CO molecules on the in-plane Ti cation sites of the rutile (TiO 2 )(110) surface, in the absence of oxygen vacancy sites. The calculations employ slab geometry and periodic bo…
This paper is devoted to the determination of the spin distribution in the spin triplet ground state of [Cu 2 ( t -Bupy) 4 (N 3 ) 2 ](ClO 4 ) 2, with t -Bupy = p - tert -butylpyridine. The crystal structure, previously solved at room temperature from X-ray diffraction, has been redetermined at 18 K from unpolarized ne…