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Long-range Ordering (long-range + ordering)
Selected AbstractsMaterials Fabricated by Micro- and Nanoparticle Assembly , The Challenging Path from Science to EngineeringADVANCED MATERIALS, Issue 19 2009Orlin D. Velev Abstract We classify the strategies for colloidal assembly and review the diverse potential applications of micro- and nanoparticle structures in materials and device prototypes. The useful properties of the particle assemblies, such as high surface-to-volume ratio, periodicity at mesoscale, large packing density, and long-range ordering, can be harnessed in optical, electronic, and biosensing devices. We discuss the present and future trends in the colloidal- assembly field, focusing on the challenges of developing fabrication procedures that are rapid and efficiently controlled. We speculate on how the issues of scalability, control, and precision could be addressed, and how the functionality of the assemblies can be increased to better match the needs of technology. [source] The magnetic moments and their long-range ordering for Fe atoms in a wide variety of metallic environmentsINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 15 2010A. Ayuela Abstract The magnitudes of Fe magnetic moments, together with their long-range ordering when appropriate, are compared and contrasted in a variety of metallic environments. Thus, Fe, in its stable body-centered-cubic (bcc) phase under ambient conditions, is considered under pressures p, which can yield different crystal structures at high p, including fcc. The modification of the ferromagnetism in bcc Fe is surveyed as one passes through a bc-tetragonal lattice to the fcc form. In the latter, evidence is presented, both from theory and experiment, that the ordering is antiferromagnetic in character. Then, binary metallic alloys with Fe atoms as the majority component are considered, Fe,Co and Fe,Ga being focal points in both ordered and disordered materials. Finally, some discussion is given, involving again both experiment and theory, of the possible spin polarization of neighboring Cs atoms when Fe impurity atoms are inserted into the low conduction electron density characterizing this heavy alkali metal under ambient conditions. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010 [source] Determination of average carbon number of petroleum waxes by X-ray diffractionJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 5 2008Sanat Kumar Eight petroleum waxes, both paraffin as well as microcrystalline, have been analysed by X-ray diffraction. The average carbon number has been estimated by the long-range ordering observed in the diffractograms of these waxes. The average carbon number has also been determined following the standard gas chromatographic (GC) method. The results obtained by X-ray diffractometry compare well with those obtained by the GC method. The former method also permits determination of the average carbon number of high melting point waxes, which is otherwise difficult using GC. [source] Possible model of protein nucleation and crystallization on porous siliconPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 8 2005S. Stolyarova Abstract The problem of macromolecular nucleation and crystallization on porous silicon surface is investigated theoretically. The fractality of the porous silicon layer is exploited. It is shown that the effective surface density of adsorbed particles on a fractal self-similar surface significantly exceeds that on a flat surface. The resulting local supersaturation explains enhanced nucleation phenomena associated with porous silicon. In addition, the self-affine fractal surface exhibits quasi-periodicity that can facilitate long-range ordering of the nucleated molecules, i.e. the crystallization process. Moreover, small elastic constants of porous silicon are favorable for the surface periodicity tuning to different lattice parameters of growing crystals. The anomalous large scaling range (from silicon interatomic distance up to 100 nm) is favorable for the crystallization of wide range of big macromolecules such as proteins. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Thiophene-based ionic liquids: synthesis, physical properties, self-assembly, and oxidative polymerization,POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 10 2008Christopher T. Burns Abstract Preparation and polymerization of methylimidazolium-based ionic liquids (ILs) that incorporate a thiophene moiety at the terminus of a C10 alkyl chain are described. Both a bromide and nitrate salt of the amphiphilic thiophene IL self-assembles in water (albeit the nitrate to a lesser extent), adopting columnar mesophases. Polarized optical microscopy and small-angle X-ray scattering (SAXS) studies show that at low water content the IL,water binary mixtures form liquid crystalline mesophases possessing significant short-range ordering due to strong , interactions between adjacent thiophene moieties. At higher water content, the short-range ordering is lost, but long-range ordering persists up to ca. 45% (w/w) water. The chemical oxidative coupling of the nitrate monomer yields a highly water-soluble polymer. Electrochemical studies show that the polymer possesses a high oxidation potential (1.95,V) and thus, is resistant to chemical doping. In dilute aqueous solution, electronic absorption spectroscopy and X-ray scattering show the polymer adopts a random, coil-like conformational state. Slight improvement in the polymer conformation can be achieved by exchange of the counter anion. Copyright © 2008 John Wiley & Sons, Ltd. [source] | |||||||||||||