Materials Literature
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Equilibrium polyethylene crystal structure, cohesive energy, and elastic constants are calculated by density-functional theory applied with a recently proposed density functional (vdW-DF) for general geometries [Phys. Rev. Lett. 92, 246401 (2004)] and with a pseudopotential-planewave scheme. The vdW-DF with its accoun…
We report the first formation of the metallic $p$-$n$ junctions, the ferroelectric (Ba,Sr)TiO$_3$ (BST) switched optimally electron-doped ($n$-type) metallic T'-phase superconductor, (La,Ce)$_2$CuO$_4$ (LCCO), and hole-doped ($p$-type) metallic CMR manganite (La,Sr)MnO$_3$ (LSMO) junctions. In contrast with the previo…
Chemical patterning of inorganic substrates by soft lithography has enabled various high-tech applications and cutting-edge fundamental research. In this paper, we report on methods for the grafting and patterned grafting of block copolymer nanotubes onto glass and mica surfaces. Under optimized conditions the density…
Perfluoroacylated derivatives of ethyl cellulose [R = CF 3 CO ( 2a ), C 2 F 5 CO ( 2b ), C 3 F 7 CO ( 2c ), C 7 F 15 CO ( 2d ), C 6 F 5 CO ( 2e )] were synthesized in good yields by the reaction of various perfluoroacylating agents with residual hydroxy groups of ethyl cellulose ( 1; DS Et, 2.69). FTIR spectra of the…
We report a chemical method by which graphitic carbon is prepared at reaction temperatures as low as 110 degrees C from readily available molecular reagents. This process requires no forcing conditions such as high pressures, intense light, or electrical discharge but is a simple, catalytic organometallic reaction. Th…
The synthesis, crystal structure, and physical characterization of five new radical salts formed by the organic donor bis(ethylenediseleno)tetrathiafulvalene (BEST) and the paramagnetic tris(oxalato)metalate anions [M(C2O4)3]3- (M = FeIII and CrIII) are reported. The salts isolated are (BEST)4[M(C2O4)3].PhCOOH.H2O wit…
The mixed ligand complex [Ni(CMA)2(im)2(MeOH)2] (where CMA = 9,10-dihydro-9-oxo-10-acridineacetate ion, im = imidazole) was prepared, and its crystal and molecular structure were determined. The nickel ions are hexa-coordinated by four oxygen atoms of the carboxylate and hydroxyl groups and by two imidazole nitrogen a…
In Staphylococcus aureus, the transport of dicarboxylates is mediated in part by the Na+-linked carrier protein SdcS. This transporter is a member of the divalent-anion/Na+ symporter (DASS) family, a group that includes the mammalian Na+/dicarboxylate cotransporters NaDC1 and NaDC3. In earlier work, we cloned and expr…
[Structure: see text] The self-assembly in the crystal state of the terminally protected, linear dipeptide Boc-(S,S)c3diPhe-(R,R)c3diPhe-NHiPr (1) through intermolecular hydrogen bonds leads to the formation of a supramolecular helix of large diameter (18 A), internally decorated with phenyl rings. As a result, a holl…
We investigate the stable configurations and electronic structures of silicon carbide nanotubes (SiCNTs) decorated by N and NHx (x=1,2) groups by using first-principles calculations. We find that these groups can be chemically incorporated into the network of SiCNTs in different ways, accompanied with the formation of…
Increasing the number of chiral centers by adjusting auxiliary coligands results in a heterometallic metamagnet with a three-dimensional homochiral framework containing both cyanide and dicyanamide bridges.
Chemical modification of wheat protein-based natural polymer materials was conducted using glyoxal as cross-linker, and the cross-linking effect was studied on mechanical properties under different humidity conditions, the molecular motions of each component, and the phase structures/components of the whole materials.…
The conventional group additivity (GA) formalism may be identically reduced to a stoichiometric and thermochemical analysis of a special class of reactions referred to as GA reactions, that is, reactions that preserve the type and number of groups. Within this approach, the performance (error) of a GA scheme is determ…
The NIR donor-acceptor charge transfer (DACT) bands of the series of trinuclear complexes trans-[(NC)5Fe(II/III)(mu-CN)RuIIL4(mu-NC)FeIII(CN)5](5/4-) (L= pyridine, 4-tert-butylpyridine, and 4-methoxypyridine) are analyzed in terms of a simplified molecular orbital picture that reflects the interaction between the dono…
The possible formation of molecular−complex phases of s-PS with styrene dimers has been investigated by their sorption in amorphous and nanoporous δ-form films. X-ray diffraction, 13 C solid state NMR, and FTIR analyses have shown that only 1,3-diphenylbutane (dpb), but not 1,4-diphenylbutane, forms a highly stable mo…
Heterobimetallic molecular precursors [Co2(acac)2mu-OH)2Cu4(dmae)4Cl4] (2) and [Ni2(acac)2(mu-OH)2Cu4(dmae)4Cl4] (3) [dmaeH = N,N-dimethylaminoethanol and acac = 2,4-pentanedionate] for the deposition of mixed oxide thin films were prepared by the interaction of tetrameric N,N-dimethylaminoethanolato copper(II) chlori…
Well-ordered ultrathin TiO x layers on Pt(111) surface, prepared by reactive evaporation of Ti in oxygen, were characterized by means of Ti 2p and O 1s core level and by valence band photoelectron spectroscopy. Depending on the details of the preparation procedures, a total of six well-ordered structures, each of them…
Using first principles DF calculations we have studied the structural and catalytic properties of Au supported on TiOx-Mo(112) films. Our theoretical models are consistent with an initial (8 x 2) Mo(112)-Ti2O3 pattern which after Au deposition gives rise to ordered Au films that completely wet the surface. The oxidati…
Centrosymmetric pyrazinium NH+...N bonded complexes allow their dielectric properties to be analyzed separately from the bulk ferroelectric polarization observed in the noncentrosymmetric DABCO monosalts. The method of dielectric permittivity measurements has been employed for monitoring polarization fluctuations gene…
We have previously developed shear-responsive hydrogels assembled from mutually attractive but self-repulsive oligopeptide modules. To explore the mechanism of material assembly, we designed and synthesized a quartet of oligopeptides. The peptide quartet contains two positively charged modules 10 and 15 amino acid res…