Materials Literature
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Dielectric dispersion measurements were made on aqueous solutions of a triple-helical polysaccharide schizophyllan over a wide concentration range 10-50 wt % at -45 to +30 degrees C. In the solution state, three different water structures with the different relaxation times tau were found, namely, bound water (taul),…
Abstract We exploited the practical sonochemical route for preparing silicon nanocrystals at room temperature and ambient pressure. This synthesis provided the very fast reaction within a few hours and the useful modification for the surface of silicon nanoparticles. The average size of prepared nanocrystals was 2.8 n…
Spin polarized density functional theory based calculations within the GGA/PW91 exchange-correlation functional have been carried out to investigate the interaction of Co, Rh, and Ir atoms with the Al-terminated α-Al 2 O 3 (0001) surface at 1/3 ML coverage. A periodic supercell approach has been used and two possible…
Two novel compounds, [Cu2(pydc)2(inta)2(H2O)2]·3H2O 1 (pydc = 2,6-pyridinedicarboxylic acid, inta = isonicotinic acid) and [Cu(pydc)2][Cu(H2O)5]·2H2O 2, have been synthesized in aqueous solution and characterized by single-crystal X-ray diffraction, elemental analyses and IR spectra. Compound 1 exhibits reverse satura…
A((=))-D, [A((=))](2)-D and [A ((=))](3)-D multi-maleimides and multi-itaconimides bearing electron-donating chromophores display a strong fluorescence quenching due to an intramolecular charge-transfer interaction. The electron-accepting C=C bond plays a key role in the intramolecular quenching. For the isomerization…
We have synthesized a homologous series of soluble, linearly conjugated oligomers and related polymers using molybdenum alkylidene catalysts. We have developed HPLC procedures to isolate the oligomers according to their chain lengths and have obtained the absorption spectra of the purified oligomers in room temperatur…
Abstract An experimental study was carried out of periodically operated NOx (NO + NO 2 ) storage and reduction on a model Pt/BaO/Al 2 O 3 catalyst powder. The effect of the reductant (propylene) injection policy on time‐averaged NOx conversion was evaluated in terms of feed composition and temperature, reductant pulse…
Sorption of organic acids by variable-charge soil occurs through both hydrophilic and hydrophobic sorption. In this study, the effect of chemical acidity and the type of acidic functional group on the relative contribution of hydrophilic and hydrophobic processes to sorption by a gibbsite-dominated and a kaolinite-dom…
Highly crystallized TiO 2 nanocrystallites (10−50 nm in size) with controlled phase structures (anatase and rutile) were synthesized using a one-step process. Flying TiC micrometer-size powder was oxidized in Ar−O 2 and Ar−H 2 −CO 2 plasmas with various configurations used for injecting oxygen into the reaction system…
The effect of sidewall functionalization on the dielectrophoretic mobility of single-walled carbon nanotubes is investigated using a 10-μm electrode gap and an alternating current electric field of 10 V and 10 Mhz. For nanotubes dispersed in aqueous solution using 1% sodium dodecyl sulfate, a high degree of alignment…
The present work is concerned with a thermodynamics model that describes the redox switching of electroactive polymers. It is well-known that, during the redox switching of these polymers, the following phenomena occurs: (i) conformational changes, (ii) income/outcome of solvent molecules with the subsequent changes i…
Short-range ferroelectric order is postulated to explain unusual one-dimensional dielectric response in ferroelectric 1,4-diazabicyclo[2.2.2]octane. In this pure organic salt, the polar regions are created in the antiferroelectric matrix of hydrogen-bonded polycationic chains due to the random proton transfers in NH +…
The Mycobacterium tuberculosis genome contains an unusually high number of proteins involved in the metabolism of lipids belonging to the Lip family, including various nonlipolytic and lipolytic hydrolases. Driven by a structural genomic approach, we have biochemically characterized the Rv1399c gene product, LipH, pre…
We have investigated the in-plane switching of cholesteric liquid crystals for reflective wavelength shifters for visible and near-infrared applications. These devices are based on the elongation of the cholesteric pitch by an electric field perpendicular to the helical axis. The transmission notch-reflection peak pos…
High-quality short-wavelength-emitting Zn x Cd 1- x Se nanocrystals with emission wavelengths tunable from 440 to 550 nm have been prepared through the incorporation of a Zn precursor into the newly formed CdSe nuclei together with the remaining Cd/Se precursors (or Cd precursor into the ZnSe nuclei with the remaining…
By using first principles calculations, we show that fine tuning of both p- and n-type doping can be realized on single-wall carbon nanotubes (SWNTs) by tuning the electron affinity or ionization potential of the organic and organometallic molecules encapsulated inside SWNTs. This novel type of SWNT-based material off…
We have performed in situ x-ray and neutron-diffraction measurements, and molecular dynamics simulations, of GeO2, an archetypal network-forming glass under pressure. Below 5 GPa, additional atoms encroaching on the first tetrahedral shell are seen to be a precursor of local coordination change. Between 6 and 10 GPa,…
A quenchable superhard high-pressure carbon phase was synthesized by cold compression of carbon nanotubes. Carbon nanotubes were placed in a diamond anvil cell, and x-ray diffraction measurements were conducted to pressures of approximately 100 GPa. A hexagonal carbon phase was formed at approximately 75 GPa and prese…
The direct calculation of the elastic and piezoelectric tensors of solids can be accomplished by treating homogeneous strain within the framework of density-functional perturbation theory. By formulating the energy functional in reduced coordinates, we show that the strain perturbation enters only through metric tenso…
The electronic structure and magnetism in the sodium nickelate NaNiO_2 in the low-temperature phase is studied from density-functional calculations using the linear muffin-tin orbitals method. An antiferromagnetic solution with a magnetic moment of 0.7 m_B per Ni ion is found. A ferrodistorsive orbital ordering is sho…