Materials Literature
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Abstract Pentacoordinate planar nonmetals (PPNs) centered in perfect pentagonal hydrocopper complexes Cu 5 H 5 X (X = B, C, N, O), as determined by density functional theory methods, are presented in this communication. The results obtained in this work complete the hypercoordinate planar carbon series with high symme…
A large variety of amphiphilic polylactide-grafted dextrans has been synthesized with controlled architecture through a three-step procedure: partial protection of the dextran hydroxyl groups by silylation; ring-opening polymerization of D, L -lactide initiated from remaining hydroxyl groups on partially silylated dex…
The tubulization process of amorphous carbon nanopillars was observed in situ by transmis-sion electron microscopy. Amorphous carbon nanopillars were transformed into graphitic tubules by annealing at 650-900 degrees C in the presence of iron nanoparticles. A molten catalyst nanoparticle penetrated an amorphous carbon…
Supercrystals of uniform nanorods and ordered assemblies of nanowires are presented. We describe a convenient method to produce highly uniform and extremely thin ZnS nanorods and nanowires. Because of their uniformity, they spontaneously assemble into crystalline (nanorods), as well as parallel and crossed (nanowire)…
5123-5126
We successfully functionalized single-walled carbon nanotubes (SWNTs) through a microwave discharge of ammonia. Evidence is supplied through Fourier transform infrared (FTIR) spectroscopy with band assignment aided by computational modeling. X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy results also pr…
Novel magnesium matrix composites reinforced with carbon nanotubes have been processed by powder metallurgy. Blends of metal powders and multi-wall carbon nanotubes were compacted by uniaxial hot pressing followed by hot isostatic pressing. A uniform dispersion of nanotubes in the metal matrix was obtained. A coating…
Abstract Two new diamines, 2,4‐diaminotriphenylamine ( 3 ) and N ‐(2,4‐diaminophenyl)carbazole ( 4 ), were synthesized via the cesium fluoride‐mediated aromatic substitution reactions of 1‐fluoro‐2,4‐dinitrobenzene with diphenylamine and carbazole, followed by palladium‐catalyzed hydrazine reduction. Amorphous and sol…
Abstract The reaction of Ni(NO 3 ) 2 ·6H 2 O with H 3 thme (trihydroxymethylethane) in the presence of NaOMe leads to a tetranuclear Ni 4 complex with a cubane‐like structure. Intramolecular ferromagnetic interactions [ J = 10 cm −1 based on H = − J ( S 1 · S 2 + S 1 · S 3 + S 1 · S 4 + S 2 · S 3 + S 2 · S 4 + S 3 · S…
Abstract Microstructures with hollow interiors, such as microspheres, microcrocks, microbowls, and micropumpkins, were prepared through the direct electrochemical oxidation of pyrrole in an aqueous solution of poly(styrene sulfonic acid) (PSSA). Scanning electron microscopy demonstrated that the microstructures posses…
A novel approach is reported for cell patterning based on addressable microheaters and a poly(N-isopropyl acrylamide) (pNIPAM) themoresponsive coating. This thermoresponsive coating is created by a radio frequency NIPAM plasma and is denoted as plasma polymerized NIPAM (ppNIPAM). Films of ppNIPAM with a good retention…
A novel functional copolymer was synthesized by modifying poly( N -isopropylacrylamide) with spirobenzopyran. The phase transition properties of the aqueous solution of this copolymer exhibited a logic-gate response to the light irradiation and to increased temperature, which has three different modes depending on the…
Two mechanisms that drive metal-to-semiconductor transitions in single-walled carbon nanotubes are theoretically analyzed through a simple tight-binding model. By considering simple structural trends, the results demonstrate that metal-to-semiconductor transitions can be induced more readily in metallic zigzag nanotub…
Cross-correlation between magnetic and dielectric properties has been attracting renewed interest because of the fundamental as well as technological importance of controlling the electric (magnetic) polarization by an external magnetic (electric) field. Here, we report the novel phenomenon that an external magnetic f…
A facile technique for fabrication of individually addressable, conducting polymer nanowire arrays of controlled dimension, high aspect ratio, and site-specific positioning using electrodeposition between electrodes in channels created on semiconducting and insulating surfaces that can be easily scaled up is reported.…
Ab initio calculations of the structural, electronic, and optical properties of CdSe nanoparticles are presented. The atomic structures of the clusters are relaxed both in vacuum and in the presence of surfactant ligands. In both cases, we predict significant geometrical rearrangements of the nanoparticle surface whil…
The temperature and electrical field dependent conductivity of $n$-type CdSe nanocrystal thin films is investigated. In the low electrical field regime, the conductivity follows $\ensuremath{\sigma}\ensuremath{\sim}\mathrm{exp}[\ensuremath{-}({T}^{*}/T{)}^{1/2}]$ in the temperature range $10<T<120\text{ }\text{…
The National Institute of Standards and Technology (NIST) has implemented a high bandwidth laser interferometer measurement system in a specialized metrology microscope. The purpose of the system is the certification of SEM magnification calibration samples by moving the sample under a finely focused stationary electr…
Abstract Differential scanning calorimetry, wide‐angle X‐ray diffraction, small‐angle X‐ray scattering, and transmission electron microscope are employed to study the microstructure of biaxially self‐reinforced high‐density polyethylene (HDPE) prepared in uniaxial oscillating stress field by dynamic packing injection…
The Haldane gap material $\mathrm{Ni}({\mathrm{C}}_{2}{\mathrm{H}}_{8}{\mathrm{N}}_{2}{)}_{2}{\mathrm{NO}}_{2}({\mathrm{ClO}}_{4})$ exhibits anomalies in its Knight shift, far infrared absorption and field-dependent gaps, which have been explained using the staggered g tensor that occurs due to the low crystal symmetr…