Materials Literature
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We present a study on the power dependence of the microwave surface impedance in thin films of the novel superconductor MgB2. 500 nm thick samples exhibiting critical temperatures ranging between 26 and 38 K are synthesized by an ex-situ post-anneal of e-beam evaporated boron in the presence of an Mg vapor at 900 C. P…
Abstract Crystallization studies at quiescent and shear states in isotactic polypropylene (iPP) containing nanostructured polyhedral oligomeric silsesquioxane (POSS) molecules were performed with in situ small‐angle X‐ray scattering (SAXS) and differential scanning calorimetry (DSC). DSC was used to characterize the q…
The reaction of M(ox) x 2H(2)O (M = Co(II), Ni(II)) or K(2)(Cu(ox)(2)) x 2H(2)O (ox = oxalate dianion) with n-ampy (n = 2, 3, 4; n-ampy = n-aminopyridine) and potassium oxalate monohydrate yields one-dimensional oxalato-bridged metal(II) complexes which have been characterized by FT-IR spectroscopy, variable-temperatu…
Excitons have recently been shown to deviate from pure bosons at densities a hundred times smaller than the Mott density. The corresponding calculations relied on the unscreened excitonic ground state wavefunction. A consistent inclusion of screening, by use of the fundamental eigenfunction of the Hulthén potential, v…
The self-organization of a chemi-sorbed mono-layer is studied as a two dimensional ordering process in presence of surface stress. As proved previously for a single phase separation, a steady surface state is yielded from the competition between the domain boundary energy and the surface stress elastic energy. In the…
This Account describes how concepts used in the fields of host-guest chemistry and chiral molecular recognition may be used to explain the unique chiral induction behavior of molecules with atropisomeric biphenyl cores when doped into a two-dimensionally ordered smectic liquid crystal phase formed by rod-shaped molecu…
The Mn12Ac single-molecule magnet has been converted for the first time into a form that contains non-carboxylate ligands. Reaction of Mn12Ac with diphenylphosphinic acid converts it into the title compound in which eight of the acetate (Ac) groups have been replaced with Ph2PO2 (P) groups. The Mn12AcP product retains…
The conditions behind the sudden approximation are critically examined. The fuzzy band expression is derived in detail from first principles. We go beyond the sudden approximation to account for both extrinsic losses and interference effects. In an extension of earlier work we discuss both core and valence satellites…
Ion implantation has become a versatile and powerful technique for synthesizing nanometer-scale clusters and crystals embedded in the near-surface region of a variety of hosts in order to create nanocomposite materials with often unique optical, magnetic, and other properties. Here we review some of the principal feat…
A fully functional switchable chromic device (see Figure) in which complementary coloration is achieved from electrostatically assembled films containing poly(aniline) (PANI) and poly(3,4-ethylenedioxythiophene) (PEDOT) is demonstrated. The color changes accompanying doping and undoping are reversible and present true…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTPolymer-Stabilized Gold Nanoparticles and Their Incorporation into Polymer MatricesMuriel K. Corbierre, Neil S. Cameron, Mark Sutton, Simon G. J. Mochrie, Laurence B. Lurio, Adrian Rühm, and R. Bruce LennoxView Author Information Departments of Chemistry and Physics Mc…
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…