Materials Literature
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The class of hybrid organic−inorganic materials called bridged polysilsesquioxanes are used for everything from surface modifiers and coatings to catalysts and membrane materials. This paper examines how bridged polysilsesquioxanes are prepared, processed, characterized, and used. In particular, it describes how attac…
The synthesis and photophysical characterization of a series of free base and zinc porphyrin containing, Newkome-type dendrimers terminated with anthraquinone groups ( FbP-G a -AQ n and ZnP-G a -AQ n ) and ethyl groups ( FbP-G a -Et n and ZnP-G a -Et n ) are described. These dendrimers were designed for use as mimics…
The synthesis and characterisation is reported of a low molecular weight organic compound to exhibit the biaxial smectic A (SmAb) phase, which shows a transition from the partial bilayer uniaxial SmAd phase to the SmAdb phase as the temperature is lowered.
The hybrid organic−inorganic material formed by polyaniline and the hexacyanoferrate anion (PAni/HCF) constitutes a molecular hybrid where the anchoring of the electroactive anion within the polymer leads to its application as a functional material that harnesses the activity of the molecular species. Transport measur…
Three novel polyurethanes with V-shaped bisazo groups ( PU1 and PU2 ) or rodlike monoazo groups ( PU3 ) in the main chain were synthesized. On irradiation with a linearly polarized laser beam, birefringence was induced in the three films to the level of 0.035, 0.037, and 0.044 for PU1, PU2, and PU3, respectively. The…
In this paper, the phase separation of A, B, and C ternary mixtures coupled with the chemical reaction of A + B C is investigated numerically on the basis of the modified time-dependent Ginzburg−Landau (TDGL) equation. The simulation results showed that, depending on the rate constant of chemical reaction and the comp…
Abstract Two series of new poly(amide imide)s having ( n ‐alkyoxy)phenyloxy side branches with various lengths, poly{ p ‐phenyleneiminoterephthaloylimino‐ p ‐phenylene[3,6‐di( n ‐alkyloxy)phenyloxy]pyromellitimide}s ( PC m TA s, m = 4, 8, 12) and poly{ p ‐phenyleneiminosebacoylimino‐ p ‐phenylene[3,6‐di( n ‐alkyloxy)‐…
New organic derivatives of "inverse-Keggin" polyoxometalate (POM) clusters, [Mo(12)O(46)(AsR)(4)](4-) (R = C(6)H(4)-4-COOH, C(6)H(3)-4-OH-3-NO(2), C(6)H(4)-4-OH), have been synthesized. Structures of the corresponding sodium or iron salts were elucidated by single-crystal X-ray diffraction and shown to be 3D structure…
The kinetics of NO reduction over wheat straw char in the presence and absence of CO was investigated in a laboratory scale fixed bed quartz reactor. Experiments were performed with char from both the raw straw and from washed straw. The wash procedure removed most of the content of potassium and other catalytic speci…
Abstract To prepare novel polyimides with enhanced thermal stability and high solubility in common organic solvents, diamine monomers, 4‐aryl‐2,6 bis‐(4‐amino phenyl)pyridine, were introduced. The diamines were reacted with three different conventional aromatic dianhydrides including pyromellitic dianhydride, benzophe…
The calculations on magnetic exchange interaction of Cl 3 FeOFeCl 3 2- and the related modeling compounds were performed by using the density functional theory coupling the broken symmetry approach. The calculated results show the absence of a direct Cl 3 Fe---FeCl 3 magnetic coupling and the effect of the terminal Cl…
The thermal reaction of ethyl undecylenate with a hydrogen-terminated porous silicon surface takes place at 85 °C to yield an organic monolayer covalently attached to the surface through Si−C bonds. The presence of traces of water in ethyl undecylenate induces a partial oxidation of the surface and leads to a surface…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTMetal Nanowire Formation Using Mo3Se3- as Reducing and Sacrificing TemplatesJae Hee Song, Yiying Wu, Benjamin Messer, Hannes Kind, and Peidong YangView Author Information Department of Chemistry, University of California Materials Science Division, Lawrence Berkeley Na…
The influence of the silica source on the morphology and the internal architecture of mesoporous fibers was investigated. It was found in all cases studied that the hexagonally packed pores are oriented in a circular manner around the fiber axis. However, the kinetics of fiber formation and the product distribution va…
We report on a general method for the calculation of the frequency-dependent optical response of clusters based upon time-dependent density functional theory (TDDFT). The implementation is done using explicit propagation in the time domain and a self-consistent program that uses a linear combination of atomic orbitals…
The generation of harmonics of the voltage response is considered when an AC current is applied through a superconducting film above T_c. It is shown that almost at all temperatures the mechanism of the temperature oscillations created by the AC current and the temperature dependence of the resistance dominates over t…
Millisecond crystal relaxation has been used to explain anomalous decay in doped alkali halides. We attribute this slowness to Fermi-Pasta-Ulam solitons. Our model exhibits confinement of mechanical energy released by excitation. Extending the model to long times is justified by its relation to solitons, excitations p…
Barkhausen noise, including both periodic and aperiodic components, is found in and near the relaxor regime of a familiar relaxor ferroelectric, PbMg$_{1/3}$Nb$_{2/3}$O$_3$, driven by a periodic electric field. The temperature dependences of both the amplitude and spectral form show that the size of the coherent dipol…
This review paper illustrates the main normal and superconducting state properties of magnesium diboride, a material known since early 1950's, but recently discovered to be superconductive at a remarkably high critical temperature Tc=40K for a binary compound. What makes MgB2 so special? Its high Tc, simple crystal st…
Directly fused diporphyrins display the extensive pi conjugation as evinced by highly perturbed electronic absorption spectra as well as lowered and largely split first oxidation potentials. Such diporphyrins prepared include meso-beta doubly linked diporphyrins 7, meso-meso beta-beta beta-beta triply linked diporphyr…