Magnetoresistance and Hall Effect in the Ferromagnetic Semiconductor GaMnAs
The resistivity, temperature, and magnetic field dependence of the anomalous Hall effect in a series of metallic Ga1-xMnxAs thin films with 0.015=
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Fracture of disordered solids in compression as a critical phenomenon: II. Model Hamiltonian for a population of interacting cracks
To obtain the probability distribution of 2D crack patterns in mesoscopic regions of a disordered solid, the formalism of Paper I requires that a functional form associating the crack patterns (or states) to their formation energy be developed. The crack states are here defined by an order parameter field representing…
Fracture of disordered solids in compression as a critical phenomenon: I. Statistical mechanics formalism
This is the first of a series of three articles that treats fracture localization as a critical phenomenon. This first article establishes a statistical mechanics based on ensemble averages when fluctuations through time play no role in defining the ensemble. Ensembles are obtained by dividing a huge rock sample into…
Fracture of disordered solids in compression as a critical phenomenon: III. Analysis of the localization transition
The properties of the Hamiltonian developed in Paper II are studied showing that at a particular strain level a ``localization'' phase transition occurs characterized by the emergence of conjugate bands of coherently oriented cracks. The functional integration that yields the partition function is then performed analy…
Ground state properties of ferromagnetic metal/conjugated polymer interfaces
We theoretically investigate the ground state properties of ferromagnetic metal/conjugated polymer interfaces. The work is partially motivated by recent experiments in which injection of spin polarized electrons from ferromagnetic contacts into thin films of conjugated polymers was reported. We use a one-dimensional n…
Evidence for the excited triplet ofCo3+inLaCoO3
The state excited from the ground singlet of ${\mathrm{Co}}^{3+}$ in ${\mathrm{LaCoO}}_{3}$ was investigated by submillimeter-wave electron spin resonance (ESR) measurements. Clear ESR signals with zero-field splitting were observed above 20 K for the first time. The activation energy is estimated to be $\ensuremath{\…
Temperature Dependence of Electron to Lattice Energy-Transfer in Single-Wall Carbon Nanotube Bundles
The electron-phonon coupling strength in single-wall carbon nanotube (SWNT) bundles has been studied directly in the time-domain by femtosecond time-resolved photoelectron spectroscopy. We have measured the dependence of H(T_e,T_l), the rate of energy-transfer between the electronic system and the lattice as a functio…
The role of contacts in molecular electronics
Molecular electronic devices are the upmost destiny of the miniaturization trend of electronic components. Although not yet reproducible on large scale, molecular devices are since recently subject of intense studies both experimentally and theoretically, which agree in pointing out the extreme sensitivity of such dev…
High Carrier Mobility in Single-Crystal Plasma-Deposited Diamond
Room-temperature drift mobilities of 4500 square centimeters per volt second for electrons and 3800 square centimeters per volt second for holes have been measured in high-purity single-crystal diamond grown using a chemical vapor deposition process. The low-field drift mobility values were determined by using the tim…
Thiophene-substituted nickel dithiolene complexes. Precursors for low band gap conjugated metallopolymers
A series of electrochemically polymerizable Ni dithiolene complexes have been prepared and their electrochemical and spectroscopic properties have been characterized. Three thiophene-substituted complexes were anodically polymerized to give polymer films whose electrochemical properties correlated well with their pred…
Structural insight into gene duplication, gene fusion and domain swapping in the evolution of PLP‐independent amino acid racemases
The X-ray crystal structure has revealed two similar alpha/beta domains of aspartate racemase (AspR) from Pyrococcus horikoshii OT3, and identified a pseudo mirror-symmetric distribution of the residues around its active site [Liu et al. (2002) J. Mol. Biol. 319, 479-489]. Structural homology and functional similarity…
Synthesis and Alkali Metal Ion-Binding Properties of a Chromium(III) Triacetylide Complex
A simple triacetylide complex of chromium(III) is synthesized for use as a potential precursor to metal-dicarbide clusters. Reaction of Me(3)SiCCLi with [(Me(3)tacn)Cr(CF(3)SO(3))(3)] (Me(3)tacn = N,N',N"-trimethyl-1,4,7-triazacyclononane) in THF generates [(Me(3)tacn)Cr(CCSiMe(3))(3)], which subsequently reacts with…
A two-dimensional discrete dislocation simulation of the effect of grain size on strengthening behaviour
In this study, the evolution of the flow stress for grain sizes ranging from about 16 to 2 μm under shear deformation was simulated using two-dimensional discrete dislocation dynamics. The analyses were confined to a single slip system and to the collective behaviour of a large number of edge dislocations, modelled as…
Pyrazolylcyclotriphosphazene Containing Pendant Polymers: Synthesis, Characterization, and Phosphate Ester Hydrolysis Using a Cu(II)-Metalated Cross-Linked Polymeric Catalyst
A multi-pyrazolyl cyclotriphosphazene containing polymerizable group N(3)P(3)(3,5-Me(2)Pz)(5)(O-C(6)H(4)-p-C(6)H(4)-p-CH=CH(2)) (2) has been prepared from the corresponding chloro derivative N(3)P(3)Cl(5)(O-C(6)H(4)-p-C(6)H(4)-p-CH=CH(2)) (1). The X-ray structures of 1 and 2 have been determined. Compound 2 undergoes…
SANS Studies of Polyelectrolyte Multilayers on Colloidal Templates
Polyelectrolyte multilayers adsorbed on colloidal particles were investigated by means of small-angle neutron scattering at contrast matching conditions. Pronounced periodic oscillations related to the latex particle size and to the layer thickness were observed. The scattering data could be well described by assuming…
Frequency-dependent elastic response at the ferroelectric phase transition ofAgNa(NO2)2
The elastic dynamics of $\mathrm{AgNa}({\mathrm{NO}}_{2}{)}_{2}$ crystals around the proper ferroelectric phase transition at ${T}_{C}=38\ifmmode^\circ\else\textdegree\fi{}C$ was investigated by ultrasonic $(f=10\mathrm{MHz})$ and dynamic mechanical analysis (f=0.6-50 Hz) techniques. The system represents a unique exa…
On the thermal degradation of poly(styrene sulfone)s. V. Thermogravimetric kinetic simulation of polyacrylamide pyrolysis
Abstract The kinetics involved in the thermal degradation of polyacrylamide under nitrogen atmosphere were studied by using consecutive reactions of a kinetic model to dynamic thermogravimetric data. The model proposed correlates the thermograms obtained at thermogravimetric and differential thermogravimetric data wit…
Degradation of low density polyethylene during extrusion. I. Volatile compounds in smoke from extruded films
Abstract Many problems with odor and taste in food packaging can be traced to degradation of the packaging materials during processing. From this starting point, the degradation of polyethylene in a commercial extrusion coating process was studied by analyzing degradation products present in smoke sampled at the extru…
NICKEL(II) COMPLEXES OF IMIDAZOLE-DERIVED LIGANDS WITH AN AMIDE GROUP: SOME COMPOUNDS WITH COMPLEX MAGNETIC BEHAVIOUR
NiL4X2·xH2O compounds [L=1-(2-carbamoylethyl)-4-methylimidazole (C4MIm), 1-(2-carbamoylethyl)benzimidazole (CBIm) or 1-(2-carbamoylethyl)-5,6-dimethylbenzimidazole (CMMBIm)] have been prepared and characterised and the effect of different axial ligands, X, on the magnetic properties of the complexes has been examined.…
Biostability of electrically conductive polyester fabrics: An in vitro study
The biostability of a series of polypyrrole (PPy)-coated polyester fabrics was investigated in an in vitro model. PPy-coated sample fabrics were incubated in saline at 37 degrees C for 1 and 2 weeks. After each period of incubation, the surface electrical resistivity of the sample fabrics was measured to monitor the c…