Materials Literature
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Abstract Methylene diphenyl isocyanate (MDI)‐based polyurethane flexible foams were decomposed by alkanolamines without a catalyst at 150°C. The decomposition products were completely separated into two layers. The upper liquid layer was a polyether polyol, and the lower liquid layer was methylene diphenyl amine (MDA)…
Porous silicon (p type) has been exposed to several chemical vapors at various partial pressures. The quenching of the photoluminescence by the adsorbates has been quantified and correlation to the electrical conductivity of the porous silicon sample has been studied. Some gases, e.g., water and benzene, have a small…
We investigate the phase diagram of mixtures of charge stabilized polystyrene spheres of two different sizes in the hard-sphere limit. We observe bulk phase separation into two disordered phases and find a new ordered phase located on the cell walls. The ordered phase occurs at volume fractions as low as 0.2, much les…
A trimolecular liquid crystalline mixture of monomers was photopolymerized while being subjected to macroscopic orientation via surface contact or continuous application of a magnetic field. Polymerization kinetics were not influenced by the macroscopic orientation, and crosslinked networks were rapidly produced. Both…
Dye molecules are widely used as optical active dopants in polymer (or sol-gel) films designed for integrated optics. A large effort is made to control the orientation of dye molecules, in order to produce macroscopic anisotropy (permanent and reversible for optical memories or transient for polarization holography) o…
International Journal of Modern Physics BVol. 08, No. 01n02, pp. 1-45 (1994) ReviewsNo AccessOVERVIEW OF ORGANIC SUPERCONDUCTORSHATSUMI MORIHATSUMI MORIInternational Superconductivity Technology Center, Nagoya Division, 2-4-1 Mutsuno Atsuta, Nagoya 456, Japanhttps://doi.org/10.1142/S0217979294000026Cited by:43 Next Ab…
Aus leicht zugänglichen chiralen Aldehyden und Pyrrol Können in einem Schritt Porphyrine wie 1 erhalten werden, deren MnCl‐Derivate effektive Katalysatoren für die enantioselektive Epoxidierung nichtfunktionalisierter Olefine sind. neue Impulse für das Design chirotroper Porphyrinliganden dürften sich auch aus der Tat…
„Pyriporphyrine”︁ wie das isolierbare Porphyrinogen‐Analogon 12 überraschen unter anderem bei der Oxidation: Diese führt je nach Reaktionsbedingungen zum Keton (C=) statt CH 2 ) oder zum Dimer. Ein durchkonjugiertes [18]Annulen‐Derivat entsteht nicht. magnified image
Abstract Porous organic sorbents containing primary amino groups and crosslinked with divinylbenzene or ethyleneglycol dimethacrylate were used for the recovery of various organic pollutants from aqueous solutions. The kinetics of sorption of these solutes is dependent on the specific area and the average pore radius…
Abstract Isothermal DSC investigations on pure as well as glass, carbon, and aramid fibre‐reinforced poly(phenylene sulfide) (PPS) were carried out in order to obtain informations on the crystallization kinetics, that is, the Avrami exponent, constant, half‐time of crystallization, and (final) degree of crystallinity.…
Abstract The objective of this research is to investigate the molecular weight, degradation mechanism, and crystalline morphology of polyethylene glycol/poly( L ‐lactide) (PEG/PLLA) copolymers during hydrolytic degradation. PEG/PLLA copolymers were prepared from cyclic L‐lactide and polyethylene glycol with molecular…
Iron nitrides of γ′-Fe4N, ε-Fe2-3N, and ζ-Fe2N have been fabricated using rf sputtering with reactive NH3 gas, which offers significant advantages over the conventional N2 gas. All but ζ-Fe2N nitride films have relative high saturation moments with a large in-plane anisotropy. The Mössbauer results are consistent with…
We performed temperature-dependent extended X-ray absorption fine structure (EXAFS) measurements on a series of nanocrystalline zirconia powders with different crystallite sizes. The results show that there is a tetragonal-to-cubic phase transition with reduction of crystallite size. The temperature dependence of the…
An accelerated route to the synthesis of dendritic macromolecules through the use of fractal components larger than the repeating unit is described. The first-generation bromide 1 and the second-generation novel branched AB4 monomer 2 can be used to prepare a highly regular fifth-generation poly(ether ester) dendrimer…
We report for the first time that doped nanocrystals of semiconductor can yield both high luminescent efficiencies and lifetime shortening at the same time. Nanocrystals of Mn-doped ZnS with sizes varying from 3.5 to 7.5 nm were prepared by a room temperature chemical process. These nanosized particles have an externa…
The LaFe13–xSix system is studied by X-ray diffraction and ac susceptibility measurements between 77 and 300 K. With the increase of the Si content x, a structural transition from cubic NaZn13-type structure to tetragonal Ce2Ni17Si9-type structure and three kinds of magnetic behavior are observed. At low x-values (1.4…
The structure of (Fe 0.6 ,Cr 0.2 ,Ni 0.2 )Sn is of the CoSn structure type with Fe, Cr and Ni disordered in the Co position. The structure contains a void surrounded by a 20-vertex polyhedron. The coordination polyhedra for Sn are hexagons and edge-capped trigonal prisms, and for Fe, ten-vertex polyhedra
Single-crystal films of 2-cyclooctylamino-5-nitropyridine have been prepared by the shear method, and the second-order susceptibility has been measured by second-harmonic generation. Polarization-dependent measurements in an a plate show that the maximum value of deff (~56 pm/V) is approximately 10 times larger than t…
The observation of shake-up satellites assigned to simultaneous excitation of 1s and 2p Mg core electrons in magnesium oxide and fluoride is reported. The presence of well-defined features due to KL double-electron excitations in x-ray photoemission spectra of these solid-state systems is assessed. Possible multiplet…
Abstract An investigation of the refractive index and third‐order nonlinear optical susceptibility χ (3) of two polypernigraniline derivatives, poly (4,4'‐diphenylimine methine) (PDPIM) and poly (4,4'‐diphenylimine p‐heptyloxybenzylidene) (PDPIHB) reveals effects of molecular structure on the linear optical and nonlin…