Materials Literature
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Energy landscape theory is becoming increasingly important to explain the behavior of proteins, clusters, and glasses. In this Perspective, [ Brooks et al .][1] chart recent progress in these areas spanning biology, chemistry, and physics. [1]: http://www.sciencemag.org/cgi/content/full/293/5530/612
Utilizing Co/Al$_2$O$_3$/Co magnetic tunnel junctions (MTJs) with Co electrodes of different crystalline phases, a clear relationship between electrode structure and junction transport properties is presented. For junctions with one fcc(111) textured and one polycrystalline (poly-phase and poly-directional) Co electro…
A magnetic "spin filter" tunnel barrier, sandwiched between a non-magnetic metal and a magnetic metal, is used to create a new magnetoresistive tunnel device, somewhat analogous to an optical polarizer-analyzer configuration. The resistance of these trilayer structures depends on the relative magnetization orientation…
A new method is presented for mesoscopic simulations of particle dispersions in nematic liquid-crystal solvents. It allows efficient first-principles simulations of the dispersions involving many particles with many-body interactions mediated by the solvents. A simple demonstration is shown for the aggregation process…
Regime transitions of poly[(S)-lactide] (PLA) crystal growth from the melt were investigated by studying the morphological changes and carrying out kinetic analysis using microscopic techniques. PLA thin films with an average layer thickness of 100 nm were isothermally crystallized at a given crystallization temperatu…
Three novel mixed-ligand lithium aggregates, [(mu(3)-EDBP)Li(2)](2)[(mu(3)-(n)Bu)Li(0.5Et(2)O)](2) (1), [(mu(3)-EDBP)Li(2)](2)[(mu(3)-OBn)Li](2) (2), and [(mu(3)-EDBP)Li(2)](2)[(mu(3)-OCH(2)CH(2)OCH(2)CH(3))Li](2) (3), have been synthesized and structurally characterized. The reaction of 2,2'-ethylidene-bis(4,6-di-ter…
Poly(ethylene oxide) (PEO), soluble in both water and many organic solvents, is grafted onto single-walled carbon nanotubes (SWNTs), and aggregation behaviors of the resulting PEO- graft -SWNT in solutions and in Langmuir−Blodgett (LB) films are investigated. SWNTs, cleaved by acid, are dispersed relatively well in DM…
We investigated magnetic, magnetotransport and magnetostriction properties of the A-type antiferromagnet Pr$_{0.46}$Sr$_{0.54}$MnO$_3$ which undergoes a first order paramagnetic-antiferromagnetic transition below T$_N$ = 210 K while cooling and T$_N$ = 215 K while warming. The zero field ($μ_0$H = 0 T) resistivity sho…
We perform molecular dynamics simulations of an idealized polymer melt surrounding a nanoscopic filler particle. We show that the glass transition temperature T(g) of the melt can be shifted to either higher or lower temperatures by tuning the interactions between polymer and filler. A gradual change of the polymer dy…
A donor−chromophore−acceptor triad (D−C−A) in which the chromophore is a Pt diimine bis(acetylide) moiety (red), the donor is phenothiazine (blue), and the acceptor is nitrophenyl (green) has been synthesized and studied spectroscopically. Irradiation leads to a charge-separated state that has a 70 ns lifetime as meas…
Optical conductivity measurements on the perovskite-related oxide CaCu3Ti4O12 provide a hint of the physics underlying the observed giant dielectric effect in this material. A low-frequency vibration displays anomalous behavior, implying that there is a redistribution of charge within the unit cell at low temperature.…
We investigate the mechanism of the resonant x-ray scattering on the Ti K edge region of ${\mathrm{YTiO}}_{3}$ using the band structure calculation combined with the local density approximation. A large intensity is obtained for the orbital superlattice spots. The calculated spectra consist of several peaks as a funct…
We have determined the adsorptive capacity of Xe on the different groups of binding sites available to this atom on a sample of single-walled carbon nanotube (SWNT) bundles. The SWNT's used were not treated after production: hence, the caps at the ends of each of the tubes remain intact. By comparing these experimenta…
Substitution of the weakly binding aqua ligand in [Cu(tren)OH2](2+) and [Cu(tpa)OH2](2+) (tren = tris(2-aminoethyl)amine; tpa = tris(2-pyridylmethyl)amine) by a cyano ligand on ferricyanide results in the assembly of heteropolynuclear cations around the cyanometalate core. In water, the reduction of the Fe(III) core t…
The diffusion of deuterated hexane in conformational isomers of a heterogeneous polymer, H 12 MDI (4,4‘-dicyclohexylmethane diisocyanate)/BD (1,4-butanediol)/PTMO (poly(tetramethylene oxide)), was investigated at a fixed hard segment content of 30 wt % and compared to the diffusion of acetonitrile. The effective diffu…
Vibrational study by Raman spectroscopy was made of the layered perovskite compounds of the formula M 2 La 2 Ti 3 O 10 (M = H, Li, Na, K, Rb), K 2 La 2 Ti 3 O 10 ·2H 2 O, and H 2 La 2 Ti 3 O 10 · n H 2 O. The spectral features above 400 cm -1 were similar in all of the unhydrated samples suggesting that the bands orig…
A dinuclear Ru(III) complex, [Ru2Cl2(PPh3)2(μ-Cl)2(μ-salhn)], has been synthesized and characterized by analytical, spectroscopic, magnetic, and X-ray diffractometry. The redox active complex displays two reductions corresponding to RuIII2/RuIIIRuII and RuIIIRuII/RuII2 couples. A weak antiferromagnetic spin coupling i…
31 P and 13 C NMR studies are reported for a smectic A liquid crystal of haxakis[4-dodecyl(4-biphenoxy)]cyclotriphosphazene. In an intense magnetic field, the long axes of the biphenylene fragments and the alkyl chains align along the magnetic field, and the cyclotriphosphazene (ctp) ring-normal points preferentially…
Molecular dynamics (MD) simulations have been performed to study the flexibility of smectite clay minerals. We aim at the quantitative understanding of the mechanical behavior of a single clay layer in a completely exfoliated state. The repeating unit of a clay layer is taken to be a o = 0.52 nm and b o = 0.902 nm wit…
Tensile properties and morphology of tetrafunctional multigraft copolymers are investigated dependent on PS volume fraction and number of branch points. It is found that tetrafunctional multigraft copolymers with 22 vol % PS and seven branch points show a surprising high strain at break of about 2100%, about double th…