Materials Literature
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Based on a model Hamiltonian with the nearest-neighbor Coulomb interaction of the itinerant e g electrons, we investigated the possibility of the coexistence of the charge-ordering phase and the antiferromagnetic phase for the manganites R 1-x A x MnO 3 with the doping of x = 0.5. Three different types of the magnetic…
The compound dimethyl-2-iodobenzoylphosphonate is unusual in that it forms well-ordered crystals that clearly show short iodine-oxygen interactions in which both the iodine and the oxygen are in their normal oxidation states. These interactions were studied using a new hybrid quantum mechanical–molecular mechanical ap…
The mean free path of phonons in superlattices is estimated. It is shown to be strongly dependent on the superlattice period due to the Umklapp scattering in subbands. It first falls with increasing the superlattice period until it becomes comparable with the latter after what it rises back to the bulk value. Similar…
Copper dissolution was investigated using electrochemical techniques including potentiodynamic scans and electrochemical quartz crystal analysis. The adsorption of iodate on a copper surface depends on the solution pH and the concentration of iodate. IO 3 - behaves both as an oxidizer and a passivating agent for coppe…
The reaction of methanol with oxygen on Pt(111) under ultrahigh vacuum condition has been investigated by infrared reflection absorption spectroscopy (IRAS). Molecular and atomic states of adsorbed oxygen existed on the Pt(111) surface, and the adsorption of oxygen at 100 K gave molecularly adsorbed oxygen that dissoc…
Spacer dependence of intersystem crossing (ISC) affected by a remote metal unpaired electron was studied in a series of copper(II) porphyrin−free base porphyrin dimers. In these dimers, fluorescence of the free base moiety is remarkably quenched by the copper counterpart which is linked via a phenanthrene, a naphthale…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTLong-Term Volume Relaxation of Bisphenol A Polycarbonate and Atactic PolystyreneChristopher G. Robertson and Garth L. WilkesView Author Information Polymer Materials and Interfaces Laboratory, Chemical Engineering Department, Virgin…
In this paper, we demonstrated that supramolecular structures of amphiphilic tripeptides can be effectively modulated by selecting the appropriate casting solvents. The tripeptide derivatives having an ammonium head and hydrophobic tails were dispersed in three kinds of solvents (nonpolar, medium nonpolar, and polar)…
The influence of the poly(α-pinene), a natural polyterpene, on growth rate of isotactic polypropylene spherulites was investigated using a dynamic solidification method. It was shown that the use of a constant cooling rate allows the obtainment of reliable growth rate data and permits one to enormously enlarge the ran…
The existence of the core−shell double gyroid morphology is proven by transmission electron microscopy and computer simulation for a linear SBV triblock copolymer and a SBV heteroarm star terpolymer, where S is polystyrene, B is poly(1,2-butadiene), and V is poly(2-vinylpyridine).
In seeking validation of Dissipative Particle Dynamics (DPD) for the mesoscopic modeling of multiphase fluid−fluid systems in external fields, simulations of a pendant drop and a drop in simple shear flow have been performed. The shape profile of the simulated pendant drop was found to be in perfect agreement with tha…
On the basis of the experimentally determined phase behavior in blends of polystyrene and random copolymers of styrene and 4-vinylpyridine, i.e., P(S x - co -4VP 1 - x )/PS, the Flory−Huggins interaction parameter is demonstrated to satisfy 0.30 < χ S,4VP ≤ 0.35. This value is substantially smaller than reported befor…
Using ab initio methods, a single isomer of D 3 h symmetry was found to be preeminent on the Ca 3 (PO 4 ) 2 cluster potential energy surface. This isomer has the distinct feature that each calcium atom is surrounded by four oxygen atoms. We studied the aggregation of this isomer in the [Ca 3 (PO 4 ) 2 ] n systemwith n…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTDirect Polycondensation of Carboxylic Acids and Amines Catalyzed by 3,4,5-Trifluorophenylboronic AcidKazuaki Ishihara, Suguru Ohara, and Hisashi YamamotoView Author Information Graduate School of Engineering, Nagoya University, Rese…
Using a simplified in-situ process, we have successfully generated relatively long IF WS2 nanotubes, in good yield and purity. The nanotubes are formed directly from WOx nanorods created from W and SiO2 during the first stage. Structural similarities and differences between IF nanotubes and carbon nanotubes have been…
The synthesis of two types of polystyrene with dendritic branching was achieved through the development of a novel method that combines living anionic polymerization with a convergent process in a one-pot reaction. The method is based on the slow addition of a reactant such as 4-(chlorodimethylsilyl)styrene (CDMSS), w…
The effects of polymerization temperature and the amount of chain extender, 2,2‘-bis(2-oxazoline), on the synthesis of lactic acid based poly(ester−amide) (PEA) were studied. High molecular weight polymer was produced only within a narrow range of polymerization parameters. The highest molecular weights were achieved…
Nanoscale palladium and nickel colloids prepared in the presence of certain tetra- n -octylammonium carboxylates contain a high proportion of nonequilibrium trigonal cross section particles. Specifically, those carboxylates which bear a hydroxy function at the α -position, e.g., tetra- n -octylammonium glycolate, exer…
The melt-state linear viscoelastic properties for a series of intercalated nanocomposites are examined. The nanocomposites are based on a short disordered polystyrene−polyisoprene diblock copolymer and varying amounts of dimethyldioctadecylammonium modified montmorillonite. The linear dynamic oscillatory moduli and th…
A simple process has been developed to create large area, highly uniform microporous thin films. Multilayers of weak polyelectrolytes were assembled onto silicon substrates by the sequential adsorption of poly(acrylic acid) and poly(allylamine) from aqueous solution. These multilayers were then immersed briefly into a…