نتایج جستجو برای: keggin type structure

تعداد نتایج: 2715186  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه بیرجند - دانشکده ادبیات و علوم انسانی 1392

in new management approaches, in the organizations with inflexible structure, existing of red tapes and interruptions caused by limitations and also non-compliance with environmental changes, create demotivation among staff. with regard to the influence of job motivational potential and its relationship to the type of organizational structure( enabling and dissuasive), the goal of this research...

Journal: :international journal of nano dimension 0
m. seyedsadjadi department of chemistry, science and research branch, islamic azad university, tehran, iran s. rashidzadeh department of chemistry, science and research branch, islamic azad university, tehran, iran n. farhadyar department of chemistry, varamin –pishva branch, islamic azad university, varamin, iran

core-shell 12-tungstophosphoric acid/tio2 (hpw/tio2) nanoparticles at 10 and 20% of hpw have been synthesized by simple in-situ sol- gel method. characterization of the samples was carried out by x-ray diffraction (xrd), scanning electron microscopy (sem), fourier transform infrared (ftir). the x-ray diffraction patterns of as prepared solid samples, indicated characteristic peaks of titania wi...

Journal: :Dalton transactions 2012
John Fielden Kyle Quasdorf Leroy Cronin Paul Kögerler

An unusual PFO(3)(2-)-templated "inverse Keggin" polyanion, [Mo(12)O(46)(PF)(4)](4-), has been isolated from the degradation reaction of an {Mo(132)}-type Keplerate to [PMo(12)O(40)](3-) by [Cu(MeCN)(4)](PF(6)) in acetonitrile. (31)P-NMR studies suggest a structure-directing role for [Cu(MeCN)(4)](+) in the formation of the highly unusual all-inorganic inverse Keggin structure.

Journal: :Chemistry 2003
Julia Wienold Olaf Timpe Thorsten Ressler

The structural evolution of Keggin-type heteropolyoxomolybdates (HPOM) during thermal treatment in propene and in propene and oxygen in the temperature range from 300 to 773 K was investigated by in situ X-ray diffraction (XRD) and in situ X-ray absorption spectroscopy (XAS) combined with mass spectrometry. During treatment in propene or hydrogen and at reaction temperatures above 673 K, the in...

Journal: :Chemical communications 2011
Yunxia Jiang Shuxia Liu Shujun Li Jun Miao Jing Zhang Lixin Wu

Non-mesogenic unit bearing Keggin-type polyoxoanions with tetra-n-octylammonium counterions exhibit an ionic liquid crystalline structure via ionic self-assembly in a certain temperature range.

The hydrothermal synthesis of two new inorganic-organic hybrid materials in which PDA (PDA = 1,10-phenanthroline-2,9-dicarboxylate) is connected to a well-defined Keggin-type polyoxometalate anion (POM) and a Ln(III) cation (POM = [SiW12O40]4−; Ln = Eu3+ (1), Er3+ (2)), are reported. These hybrids are characterized by elemental analyses, IR spectra and single-crystal X-ray diffraction. Single-c...

Journal: :Journal of the American Chemical Society 2009
Lingaiah Nakka Julie E Molinari Israel E Wachs

The molecular structures and surface chemistry of mixed metal oxide heteropolyoxo vanadium tungstate (H(3+x)PW(12-x)V(x)O(40) with x = 0, 1, 2, and 3) Keggin nanoparticles (NPs), where vanadium is incorporated into the primary Keggin structure, and supported VO(x) on tungstophosphoric acid (TPA, H(3)PW(12)O(40)), where vanadium is present on the surface of the Keggin unit, were investigated wit...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2009
Holger Wille Maheswaran Shanmugam Muralee Murugesu Julian Ollesch Gerald Stubbs Jeffrey R Long Jiri G Safar Stanley B Prusiner

Prions are composed solely of an alternatively folded isoform of the prion protein (PrP), designated PrP(Sc). N-terminally truncated PrP(Sc), denoted PrP 27-30, retains infectivity and polymerizes into rods with the ultrastructural and tinctorial properties of amyloid. We report here that some polyoxometalates (POMs) favor polymerization of PrP 27-30 into prion rods, whereas other POMs promote ...

2011
Julie E. Molinari Lingaiah Nakka Taejin Kim Israel E. Wachs

Molybdenum-based Keggin polyoxometalates (POMs) containing vanadium, with the formula H3+xPMo12 xVxO40 (MPAV) and x varying from0 to 3, exhibit unique catalytic properties because of their bifunctional nature and have been investigated as catalysts both for acidic and for oxidative reactions. 3 The addition of vanadium centers are beneficial for redox catalysis, shifting the molybdophosphoric a...

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