Materials Literature
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Atomic sites with multiple substituents are common in minerals, and correct site assignment of substituents in structure refinement is of fundamental importance. Substituents must be assigned to particular sites to fit the observed site scattering and chemical analysis, but the assignments are rarely made with mathema…
The effect of pretreatment of several cis-1,4-polyisoprene containing rubbers on their biodegradability was examined. Tests were carried out with six recently isolated and characterized rubber degrading bacteria belonging to the genera Gordonia (strains Kb2, Kd2 and VH2), Mycobacterium, Micromonospora and Pseudomonas.…
A read–write–erase system for micropatterning tungsten oxide films is reported here. The Figure shows blue spots of tungsten bronze formed locally on tungsten oxide film by locally generating a reductant close to the film. The process utilizes the scanning electrochemical microscope (SECM) not only to inject charge bu…
Abstract Structural and physical properties of the Cu salts of a series of π-acceptors N,N′-dicyanobenzoquinonediimines (DCNQIs) are described. The most notable feature of this system is that 3d electrons in Cu interact with pπ electrons in DCNQI near the Fermi level. This unique feature has provided a lot of interest…
Crystalline cadmium sulfide is a semiconductor for which the wurtzite and zinc blende structures are energetically almost degenerate. Due to quantum-confinement effects, it is possible to tune the optical properties of finite cadmium sulfide clusters by varying their size. Here, we report results of a theoretical stud…
Si 3 N 4 ceramics were fabricated by tape casting of a raw‐powder slurry seeded with three types of rodlike β‐Si 3 N 4 particles. The effects of seed size on the microstructure and mechanical properties of the sintered specimens were investigated. All the seeded and tape‐cast silicon nitrides presented an anisotropic…
Reaction probabilities of OH • radicals under steady state conditions were determined over TiO 2 (anatase and rutile), SiO 2 (fused quartz), α-Al 2 O 3, and Au surfaces. The OH • radicals were produced from water in a microwave cavity and were detected by laser-induced fluorescence spectroscopy. At 308 K the reaction…
A Nd3+-doped 1.3 μm fiber amplifier has the potential to be an efficient, high-gain device. A major problem to overcome is the long wavelength of the gain spectrum. In the majority of Nd3+-doped glasses the gain is shifted out of the second telecom window as a result of long-wavelength emission and signal excited-stat…
Two novel Ru(II)-Rh(III) polypyridine dyads, containing carboxylic functions at the Rh(III) unit, Rh III (dcb) 2 -(BL)-Ru II (dmp) 2 and Rh III (dcb) 2 -(BL)-Ru II (bpy) 2 (bpy = 2,2‘-bipyridine; dcb = 4,4‘-dicarboxy-2,2‘-bipyridine; dmp = 4,7-dimethyl-1,10-phenanthroline; BL = 1,2-bis[4-(4‘-methyl-2,2‘-bipyridyl)]eth…
Molecular dynamics (MD) simulations of liquid aluminum oxide $({\mathrm{Al}}_{2}{\mathrm{O}}_{3})$ were carried out on a system with up to 1800 particles, using a pairwise potential. All simulations were done in the microcanonical ensemble, for two densities, $3.0$ and $3.175 \mathrm{g}/{\mathrm{cm}}^{3},$ at temperat…
In this preliminary report we present the mesomorphic properties and electro-optic investigations of three new 'banana-shaped' mesogens. The materials are structurally similar to Niori's the original bent-core materials but possess alkylthio substituents in place of alkoxy substituents. Microscopic investigations reve…
A novel bent-rod hexacatenar liquid crystal is reported that displays a hexagonal columnar (Col h ) phase. The organization of conjugated hexacatenar mesogens in the columnar phase is of interest for their anisotropic electronic properties. The emissive nature of the mesogens varies over the temperature range of the C…
An investigation of the morphological behavior of a series of graft copolymers having multiple regularly spaced, tetrafunctional branch points has been carried out. The behavior of these materials, comprised of polyisoprene backbones with two polystyrene arms grafted to the backbone at each branch point, is shown to b…
A stepwise temperature- and pressure-scanning thermal analysis method was developed to measure glass-transition temperature Tg in the two-phase polymer–gas systems as a function of gas pressure p, and was used to confirm recent theoretical predictions that certain polymer–gas systems exhibit retrograde vitrification,…
In our search for a more versatile protecting group that would exhibit fast release rates for peptides, we have designed and developed the p -hydroxyphenacyl (pHP) group as a new photoremovable protecting group. We report the application of this protecting group for the dipeptide Ala-Ala ( 1 ) and for the nonapeptide…
The influence of manganese on the crystallographic phase and the microstructure of BaTi 1− x Mn x O 3 ceramics (0 ≤ x ≤ 0.05) is investigated. The crystal structure at room temperature changes from tetragonal to hexagonal between x = 0.005 and 0.017, which causes a drastic change in the microstructure. The Jahn_Teller…
The rheological behavior of intercalated polystyrene/layered silicate nanocomposites was investigated. Both storage and loss moduli increased with silicate loading at all frequencies and showed non-terminal behavior at low frequencies which is a typical behavior of non-homogeneous systems with ordered microstructures.…
The progress in the synthesis of organolanthanide complexes supports the exploration of these compounds as initiators for ring-opening polymerization (ROP) of lactones. The performance of these initiators in terms of yield, molecular weight, polydispersity, stereoregularity is affected by the ligands and by the oxidat…
A general and efficient procedure is presented, which allows us to reduce the computational efforts for the calculation of the energy levels of high-nuclearity spin clusters. The method consists of block factorizing the Hamiltonian matrix using the invariance of the spin Hamiltonian with regard to interchanges of spin…
A lower critical solution temperature (LCST) phase transition is reported for blends of the biodegradable polymers poly(D,L-lactide) (PDLA) and poly(ε-caprolactone) (PCL). From light scattering measurements the cloud point curve is determined to have a critical temperature of 86°C and a critical concentration of mass…