Materials Literature
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A series of new rigid−flexible copolyethers containing blue- and yellow-emitting conjugated segments have been synthesized. The thermal, mechanical, and optical properties of the polymers are controlled by the type of the comonomers, their ratio at the preparation stage, and the length of the flexible spacer, as well…
Two new SF 5 -terminated perfluoroalkylsilanes SF 5 (CF 2 CF 2 ) n CH 2 CH 2 SiCl 3 ( n = 1 and 2) were synthesized by addition of trichlorosilane to the corresponding synthetic SF 5 -terminated perfluoroalkenes by hydrosilylation. Thin films of these SF 5 -silanes on clean silicon oxide substrates were characterized…
Two very large cyclophanes (3, C(132)H(92)O(8)S(4); 4, C(172)H(120)O(8)S(4)) were prepared by means of short syntheses ( approximately 5 steps) from commercial starting materials. In each of these cyclophanes, two octaphenylnaphthalene subunits or two 1, 3-bis(pentaphenylphenyl)benzene subunits were tethered to form t…
The present study reports the development of kinetic probes to determine the possible role of hydroxyl radicals in the polyoxometalate-mediated photocatalytic oxidation of aqueous chlorinated organic compounds. Photocatalytic oxidation of the model chloroaromatic 1,2-dichlorobenzene (DCB) was carried out in oxygenated…
An unresolved issue of peroxidase activity is the role played by the hydrogen bond between the proximal histidine ligand and a highly conserved aspartate group. It has been postulated that this hydrogen bond imparts imidazolate character to the axial ligand, increasing its donating ability and stabilizing the high val…
The melt intercalation and curing behavior of phenolic resin (P1) were investigated by use of layered silicates, such as pristine montmorillonite (PM), dodecylammonium-modified montmorillonite (C12M), octadecylammonium-modified montmorillonite (C18M), benzyldimethyloctadecylammonium-modified fluorohectorite (C18BH), a…
Mesoporous silica SBA-15 molecular sieves have been incorporated with various amounts of vanadium via incipient-wetness impregnation with vanadium oxide triisopropoxide in hexane followed by calcination. The products (VSBA-15) have been characterized by nitrogen adsorption and diffuse reflectance UV−visible and electr…
An analogy between combinatorial chemistry and Monte Carlo computer simulation is pursued. Examples of how to design libraries for both materials discovery and protein molecular evolution are given. For materials discovery, the concept of library redesign, or the use previous experiments to guide the design of new exp…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTAssembly of Gold Nanostructured Films Templated by Colloidal Crystals and Use in Surface-Enhanced Raman SpectroscopyPeter M. Tessier, Orlin D. Velev, Anand T. Kalambur, John F. Rabolt, Abraham M. Lenhoff, and Eric W. KalerView Author Information Department of Chemical…
Following our previous papers on the mechanism of cyclic esters polymerization induced by tin(II) octoate (Sn(Oct) 2 ) and particularly papers on ε-caprolactone (CL), the present work shows that l, l -dilactide/Sn(Oct) 2 does not differ mechanistically from the CL/Sn(Oct) 2 system. Sn atoms bonded through alkoxide gro…
The switching kinetics of polarization reversal using lead zirconate titanate (PZT) thin-film capacitors for nonvolatile memories has been analyzed in terms of the Ishibashi model. A practical 16 kbit PZT memory was used in this work. The polarization reversal ratio agrees well with the theoretical model of the first…
Step-flow crystal growth is possible on a very large scale on Si(111). The growth mode changes at the $(7\ifmmode\times\else\texttimes\fi{}7)\ensuremath{-}(``1\ifmmode\times\else\texttimes\fi{}1'')$ phase-transition temperature. Nucleation of new steps can be controlled by intentionally introducing contaminants or par…
We investigate the variation of the electromigration driving force felt by Na adatoms in the vicinity of other adatoms, adatom rows, and small planar islands. The wind valence tensor is computed by a model calculation for noncompact Na clusters on a semi-infinite flat jellium substrate that carries an electrical curre…
Exciton states confined in a spherical quantum dot (QD) are studied in a weak confinement regime with the consideration of the electron-hole exchange interaction and induced surface charge density. Except for special cases, most exciton states are longitudinal (L)--transverse (T) mixed modes. With an increase of radiu…
Bacterial cell walls are cross-linked in the final step of biosynthesis by specific D-alanyl-D-alanine(DD)-peptidases/transpeptidases. The natural substrates of these enzymes should therefore be segments of peptidoglycan, but high specificity for such structures has yet to be demonstrated. The binding of dipeptides to…
We start with an analysis of the Raman spectra of Ge nanocrystals obtained in previous studies and demonstrate that in many cases the observed experimental peak attributed to Ge in fact originates from the Si substrate. We further compare various experimental ways to separate the Ge signal from that of the substrate a…
We have measured the energy- and momentum-dependent loss function of ${\mathrm{Li}}_{2}{\mathrm{CuO}}_{2}$ single crystals by means of electron energy-loss spectroscopy in transmission. Using the same values for the model parameters, the low-energy features of the spectrum as well as published Cu ${2p}_{3/2}$ x-ray ph…
Slow dynamics in a fluid are studied in one of the most basic systems possible: polydisperse hard spheres. Monodisperse hard spheres cannot be studied as the slow down in dynamics as the density is increased is preempted by crystallization. As the dynamics slow they become more heterogeneous, the spread in the distanc…
We present molecular-dynamics simulations of the atomic arrangement in molten and amorphous germanium. We start with 512 atoms in a supercell and then heat it above the melting temperature. Subsequent rapid quenching results in a continuous random network (CRN) with a radial distribution function (RDF) in excellent ag…
To elucidate the effect of the aspect ratio of protein on the diffusion in gels, the diffusion of a rodlike protein, tropomyosin, in two kinds of polysaccharide gels, agarose and carrageenan, has been investigated by electronic speckle pattern interferometry method and compared with that of a globular protein, myoglob…