Materials Literature
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Abstract Poly(trimethylene terephthalate) (PTT) was prepared by the ring‐opening polymerization of its cyclic dimer. Antimony(III) oxide, titanium(IV) butoxide, dibutyltin oxide, and titanium(IV) isopropoxide were used as catalysts. Among the catalysts, titanium(IV) butoxide was the most effective for the same reactio…
We investigate charge pumping in semiconducting carbon nanotubes by a travelling potential wave on the surface of a piezoelectric quartz substrate. We estimate the magnitude and profile of the potential wave as its passes the nanotubes and show how this results in the pumping of charge in packets. By tuning the potent…
The present work reports isothermal gas/solid equilibration kinetics for Nb-doped TiO(2) (0.65 atom %) at elevated temperatures (1073-1298 K) within narrow ranges of oxygen activity spanning between 10(-13) Pa and 75 kPa. The equilibration kinetics were monitored using electrical conductivity measurements. The kinetic…
Abstract Dense, lead‐free ceramics with composition of (K 0.5 Na 0.5 ) 0.96 Sr 0.02 Nb 1– x Mn x O 3 ( x = 0, 0.01, 0.02, 0.03, 0.04) were successfully prepared by a conventional mixed‐oxide method. The X‐ray diffraction patterns revealed pure peroveskite structure after Mn doping as compared to the original compositi…
We introduce a robust and efficient methodology to solve the Ornstein-Zernike integral equation using the pseudoarc length (PAL) continuation method that reformulates the integral equation in an equivalent but nonstandard form. This enables the computation of solutions in regions where the compressibility experiences…
Phytochemical screening of the roots of Gomphrena macrocephala, with particular attention to its triterpene glycoside constituents, has resulted in the isolation of two new oleanane glycosides (1 and 2) and a new taraxerane glycoside (3). The structures of 1-3 were determined as 11alpha,12alpha-epoxy-3beta-[(O-beta-D-…
The basic science in quantum transport of nano-scaled 'devices' is largely based on the availability of suitable model systems . Nanostructures built from conventional metals are typically in the diffusive transport regime. Semiconductors, as the starting material for nanodevices, are different. Because of the low car…
Density functional theory is employed to study Pd and Pd/Ni alloy monatomic chain-functionalized metallic single walled carbon nanotubes (SWNT(6,6)) and semiconducting SWNT(10,0), and their interactions with hydrogen molecules. The stable geometries and binding energies have been determined for both isolated chains an…
Reaction of two transition metal cations M (M = V V , Fe III ) on the open Wells–Dawson anion α-[{K(H 2 O) 2 }Si 2 W 18 O 66 ] 15– leads to dinuclear and tetranuclear complexes, respectively. The molecular anions [{KV 2 O 3 (H 2 O) 2 }(Si 2 W 18 O 66 )] 11– and [{Fe 4 (OH) 6 }(Si 2 W 18 O 66 )] 10– have been structura…
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
The physicochemical and mechanical properties of amine-terminated covalently bound poly(ethylene glycol) (PEG) layers are dependent on fabrication methods. In particular, the use of a ϑ solvent yields dense polymer layers with properties not well described by traditional models. Light diffraction techniques were used…
Jewel-box: In a hierarchical process, three molecules of a calix[4]arene (blue) and six of barbituric or cyanuric acid (green) assemble into double-rosette boxes, which assemble into columns, which in turn assemble into columnar liquid-crystalline phases (see picture). The resulting mesophases have a remarkable therma…
Modulierbar: Optisch reversibel schaltbare fluoreszierende Verbindungen wurden synthetisiert, deren sichtbare Fluoreszenz mit Licht der Wellenlänge 360–400 nm bis auf 6 % unterdrückt und dann mit rotem Diodenlaserlicht wiederhergestellt werden kann. Die fluoreszierenden Schalter bieten Möglichkeiten für die Datenspeic…
In a stable condition: Oxyhydroxide colloids of chromium deposited on silica gel are selective, stable catalysts for the autoxidation of cyclohexane (CyH). The CrIII colloids, generated in situ, are immobilized by a column precipitation chromatographic technique (see picture). An increased yield of cyclohexanone (QO)…
The synthesis, characterization, and nucleophilic aromatic substitution (NAS) behavior of 3,5-difluorophenyl sulfone, 3, are reported. The reactivity of the electrophilic sites, activated by only a phenylsulfonyl group located in the meta position, in 3 was probed via NMR spectroscopy and model reactions and was deter…
The synthesis, characterization, and X-ray crystal structure of a well-defined yttrium(III) amide complex with the bis(thiophosphinic amide) ligand is reported. The new complex exhibits high rates and good control for lactide polymerization. The polymerization kinetics and mechanism are studied under a range of differ…
We report on the Fe17 high-spin molecular cluster and show that this system is an exemplification of nanostructured dipolar magnetism. Each Fe17 molecule, with spin S=35/2 and axial anisotropy as small as D approximately -0.02 K, is the magnetic unit that can be chemically arranged in different packing crystals while…
Nanocrystalline magnetite Fe3O4 samples with a grain size of about 40 nm have been synthesized by an optimized sol-gel method. The single phase of spinel magnetite was confirmed by both X-ray diffraction and transmission electron microscopy. It has been found that the magnetoresistance of the samples at low field (LFM…
First principles density functional pseudopotential calculations have been used to investigate the nature of interactions between single-walled carbon nanotubes (SWNTs) and intercalated transition metal metallocene complexes, M(eta-C(5)H(5))(2) (MCp(2)). Three composites, MCp(2)-graphene (d(t)=infinity), MCp(2)@(17,0)…
Magnetic measurements using a superconducting quantum interference device and magnetic force microscopy were performed on fullerene films irradiated with $250\phantom{\rule{0.3em}{0ex}}\mathrm{keV}$ Ar and $92\phantom{\rule{0.3em}{0ex}}\mathrm{MeV}$ Si ions, to compare the effects of electronic excitation and collisio…