Materials Literature
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Large spectral fluctuations, on a time scale of many seconds, are demonstrated in the surface-enhanced Raman scattering of single rhodamine 6G molecules adsorbed on silver nanocrystals and excited at 532 nm. These fluctuations are especially evident in the case of the vibrational bands at 614 and 774 cm -1 . A definit…
In this work the complete valence-band structure of the molybdenum dichalcogenides ${\mathrm{MoS}}_{2},$ ${\mathrm{MoSe}}_{2},$ and $\ensuremath{\alpha}\ensuremath{-}{\mathrm{MoTe}}_{2}$ is presented and discussed in comparison. The valence bands have been studied using both angle-resolved photoelectron spectroscopy (…
The growth of vertically aligned carbon nanotubes using a direct current plasma enhanced chemical vapor deposition system is reported. The growth properties are studied as a function of the Ni catalyst layer thickness, bias voltage, deposition temperature, C2H2:NH3 ratio, and pressure. It was found that the diameter,…
Two-dimensional lattices of carbon, boron-nitride, and fluorine-carbon compositions are treated with ab initio methods in order to evaluate and compare their mechanical properties in a uniform fashion. The demonstrated robustness of continuum elasticity up to very small length-scale allows one to define and compute th…
Several proteases require propeptides for the correct folding of their own protease domain. We have recently found that the propeptide from a thermostable subtilisin homolog aqualysin I can refold subtilisin BPN' when added in trans. Here, we constructed chimeric genes with subtilisin E and aqualysin I to attempt the…
Abstract Biosynthetic processes for production of linear proteins, polysaccharides, and polyhydroxyalkanoates (PHAs) are discussed. Processes for converting the linear biopolymers into useful products are described. Techniques and additives for improving the processability of PHAs and potential applications of PHAs ar…
Abstract A series of poly(arylene ether)s were successfully prepared by aromatic, nucleophilic substitution reactions with various perfluoroalkyl‐activated bisfluoromonomers with 4,4′‐bishydroxybiphenyl and 4,4′‐bishydroxyterphenyl. 4,4′‐Bishydroxyterphenyl was synthesized through the Grignard coupling reaction of mag…
Poly(lactic acid) (PLA) is a biodegradable polymer, but its applications are limited by its high cost. Blending granular starch with PLA reduces the cost, but the blend has poor strength properties. In this study, a 55/45 (w/w) mixture of PLA (weight-average molecular weight = 120,000 Da) and dried wheat starch was bl…
A previously unexplored class of heterocyclic bidentate chelating groups, 6-carboxamido-5,4-hydroxypyrimidinones (6-substituted-HOPYs), have been synthesized by two routes that provide a flexible entry into this ligand system. These are related to, but distinct from, the hydroxypyridonates and have been characterized…
Thermoplastic elastomers of a styrene−butadiene−styrene (SBS) triblock copolymer containing grafts of an azobenzene side-chain liquid crystalline polymer were prepared by polymerization of an azobenzene acrylate monomer in solutions with dissolved SBS. Stretching thin films at room temperature induces long-range orien…
Two new porphyrin arrays-a hexamer and a nonamer-have been synthesized and characterized by elemental analysis as well as mass, (1)H NMR, and UV-vis spectroscopic methods. The scheme of construction of these arrays employs a synthetic protocol involving sequential "organic" and "inorganic" reactions conducted, respect…
The lamello-columnar mesophase of a [1]benzothieno[3,2-b][1]benzothiophene-2,7-dicarboxylate (BTBT) derivative has been investigated by means of X-rays on an aligned sample. The most probable model of molecular organisation corresponds to an assembly of microcolumns made of alternatively crossed molecules, within the…
The aluminum chloride complexes [(O∼∼O)AlCl] 2, I, [(O∼CHMe∼O)AlCl] 2, II, and TPPAlCl, III, where O∼∼O = 5,5‘,6,6‘-tetramethyl-3,3‘-di- tert -butyl-1,1‘-biphenoxide, O∼CHMe∼O = 2,2‘-ethylidenebis-4,6-di- tert -butylphenoxide, and TPP = tetraphenyl porphyrin, are shown to be inactive in initiating the ring-opening pol…
The nuclear and magnetic structures of the monoclinic ( P 2 1 / n, A-LFP) and rhombohedral ( R 3̄ B-LFP) forms of Li 3 Fe 2 (PO 4 ) 3 have been solved by using powder neutron diffraction at room temperature and 1.5 K on polycrystalline samples. Both structures are built on [Fe 2 (PO 4 ) 3 ] ‘lantern units' that are co…
The crystallization of ordered microporous−mesoporous silica, SBA-15, has been investigated in the presence of an ionic salt, such as sodium chloride, under microwave-hydrothermal conditions. The crystallization was performed by templating a silica precursor (tetraethyl orthosilicate or sodium silicate) with pluronic1…
Abstract A new six‐membered cyclic carbonate monomer, 5‐benzyloxy‐trimethylene carbonate, was synthesized from 2‐benzyloxy‐1,3‐propanediol, and the corresponding polycarbonate, poly(5‐benzyloxy‐trimethylene carbonate) (PBTMC), was further synthesized by ring‐opening polymerization in bulk at 150 °C using aluminum isob…
Magnetization and magnetoresistivity studies of Fe/V (001) superlattices are reported. The first giant magnetoresistance peak with respect to the vanadium and iron layer thicknesses is investigated. The interlayer antiferromagnetic coupling strength is found to show a peak at a vanadium layer thickness of 13 atomic mo…
Abstract Alpha keratin fibers (hairs, wools, quills, and other mammalian appendages) together with fibroin fibers such as silks and spiders webs are all highly extensible fibrous proteins for which the mechanical properties are of primary importance both to the animal from which they originate and their ultimate appli…
In the paper we predict a distinctive change of magnetic properties and considerable increase of the Curie temperature caused by the strain fields of grain boundaries in ferromagnetic films. It is shown that a sheet of spontaneous magnetization may arise along a grain boundary at temperatures greater than the bulk Cur…
Using total energy calculations, based on interaction potentials from the embedded atom method, we show that the presence of the tip not only lowers the barrier for lateral diffusion of the adatom towards it, but also shifts the corresponding saddle point. For a Cu adatom at a (100) microfacetted step on Cu(111) this…