Materials Literature
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The effect of geometrical frustration in a two-dimensional $1∕4$-filled strongly correlated electron system is studied theoretically, motivated by layered organic molecular crystals. An extended Hubbard model on the square lattice is considered, with competing nearest-neighbor Coulomb interaction $V$, and that of next…
The effect of adding various kinds of acids HX (X = Cl, Br, I, CF(3)COO, CF(3)SO(3), TFPB ((3,5-(CF(3))(2)C(6)H(3))(4)B) to isomeric tetra(2-pyridyl)porphyrin, tetra(3-pyridyl)porphyrin, and tetra(4-pyridyl)porphyrin (TpyP(2), TpyP(3), and TpyP(4)) in dichloromethane solution has been investigated through the combined…
Something to fret about: Luminescent semiconductor nanocrystals are covered with polymeric ligands which form many bonds to the nanocrystal (NC) and increase their solubility. The ligands are decorated with an organic dye molecule (see picture) so that the electronic interaction in individual nanocrystal–dye complexes…
Abstract Cyclodextrins are cyclic oligosaccharides. Cyclodextrin molecules can form inclusion complexes with a large number of organic molecules. The properties of cyclodextrins enable them to be used in a variety of different textile applications. Cyclodextrins can act as auxiliaries in washing and dyeing processes,…
We report the preparation of nanosized silicon nitride (Si 3 N 4 ) ceramics via high‐energy mechanical milling and subsequent spark plasma sintering. A starting powder mixture consisting of ultrafine β‐Si 3 N 4 and sintering additives of 5‐mol% Y 2 O 3 and 2‐mol% Al 2 O 3 was prepared by high‐energy mechanical milling…
The changes in the morphology of Ba-oxide-based NO x storage/reduction catalysts were investigated using time-resolved X-ray diffraction, transmission electron microscopy, and energy dispersed spectroscopy. Large Ba(NO 3 ) 2 crystallites form on the alumina support when the catalyst is prepared by the incipient wetnes…
1st and 2nd heterogeneous deacetylations of alpha- and beta-chitins in a multistep process by means of freeze-pump out-thaw (FPT) cycles in the presence of 50% (w/v) NaOH, for temperatures ranging from 80 to 110 degrees C, were compared to the classical method using argon as the medium atmosphere. It was clearly demon…
Metal Al particle surfaces were modified by fine γ‐Al 2 O 3 grains using a mixture of Al and Al(OH) 3 powders, which was pressureless sintered at a temperature of 600°C in vacuum. All the constituents on original Al particle surfaces were transformed into γ‐Al 2 O 3 phase after sintering. No dense passive oxide layers…
We report the synthesis of hyperbranched glycopolymers by self-condensing vinyl copolymerization (SCVCP) of the methacrylic AB* inimer 2-(2-bromoisobutyryloxy)ethyl methacrylate (BIEM) with 3- O -methacryloyl-1,2:5,6-di- O -isopropylidene-α- d -glucofuranose (MAIGlc) via atom transfer radical polymerization, followed…
We describe the syntheses and characterization of a series of periodic mesoporous organosilica (PMO) materials containing various organic functional groups prepared using the direct synthesis method under basic conditions. This synthetic method allows the production of mesoporous organosilicas that have large surface…
Abstract Starch–poly(vinyl alcohol) (PVA) blends with different compositions were prepared and crosslinked with borax by in situ and posttreatment methods. Various amounts of glycerol and poly(ethylene glycol) with a molecular weight of 400 were added to the formulations as plasticizers. The pure starch–PVA blends and…
Abstract Starch was crosslinked with poly(vinyl alcohol) (PVA) by boric acid. A suitable plasticizer and defoamer were added to obtain the brei. A film from the starch and PVA (SP film) was prepared by casting. The effects of various factors, such as the crosslinking temperature, the PVA content, and the amounts of gl…
We have found a method for a diameter-selective removal of metallic single-walled carbon nanotubes (m-SWCNTs) from semiconducting (s-) ones by stirring or sonicating SWCNT powder in tetramethylene sulfone (TMS)/chloroform solution with nitronium hexafluoroantimonate (NO2SbF6: NHFA) and nitronium tetrafluoroborate (NO2…
Abstract Summary: This communication describes the compatibilization efficiency of organically modified montmorillonite (OMMT) in immiscible polycarbonate (PC)/poly(methyl methacrylate) (PMMA) blends for the first time. The size of the dispersed PC particles was reduced significantly upon the addition of OMMT (6 wt.‐%…
The method of ultrasound irradiation is used for anchoring metallic nanocrystals (Ag, Au, Pd, and Pt) onto the surface of polystyrene spheres. In former studies, almost all the sonochemically prepared, coated metallic nanomaterials were formed as amorphous nanoparticles (Pol, V. G.; et al. Langmuir 2002, 18, 3352; Pol…
Nanoisland gold films, deposited by vacuum evaporation of gold onto Si(100) substrates, were irradiated with 1.5 MeV Au$^{2+}$ ions up to a fluence of $5\times 10^{14}$ ions cm$^{-2}$ and at incidence angles up to $60^{\circ}$ with respect to the surface normal. The sputtered particles were collected on carbon coated…
Using a new analytic quantum mechanical method based on Slater's Xalpha method, we show that a fairly accurate estimate of the total energy of a molecule can be obtained from the exact energies of its constituent atoms. The mean absolute error in the total energies thus determined for the G2 set of 56 molecules is abo…
The structure of very high-density amorphous (VHDA) ice has been modelled by positionally disordering three crystalline phases, namely ice IV, VI and XII. These phases were chosen because only they are stable or metastable in the region of the ice phase diagram where VHDA ice is formed, and their densities are compara…
We report the absorption cross-section of colloidal InAs quantum dots of mean radii from 1.6 to 3.45 nm. We find excellent agreement between the measured results and calculated values based on a model of small-particle light absorption. The absorption cross-section per dot is 6.2 x 10(-16)R(3) cm(2) at 2.76 eV and 3.1…
Tellurium impurity centers in ZnSe were individually probed with time-resolved photoluminescence (PL) spectroscopy. Resolution-limited peaks with an ultra-low spatial density originate in the recombination of excitons deeply bound to isolated nearest-neighbor isoelectronic Te pairs (Te2). This interpretation is confir…