نتایج جستجو برای: and 29si chemical shift

تعداد نتایج: 16882937  

Journal: :Physical review letters 2010
H Mukuda T Ohara M Yashima Y Kitaoka R Settai Y Onuki K M Itoh E E Haller

We report 29Si NMR study on a single crystal of the heavy-fermion superconductor CeIrSi3 without an inversion symmetry along the c axis. The 29Si Knight-shift measurements under pressure have revealed that the spin susceptibility for the ab plane decreases slightly below T(c), whereas along the c axis it does not change at all. The result can be accounted for by the spin susceptibility in the s...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه رازی - دانشکده علوم 1392

a novel acrylic acid-functionalized fe3o4 magnetic nanoparticle with a core-shell structure was developed for utilization as a heterogeneous organosuperacid in chemical transformations. the structural, surface, and magnetic characteristics of the nanosized catalyst were investigated by various techniques such as transmission electron microscopy (tem), thermogravimetric analysis (tga), and ft-ir...

2013
Bernd Wrackmeyer Hartmut Oehme H. Oehme

Two intramolecularly donor-stabilized silenes, l-(8-dimethylamino-l-naphthyl)-l,2,2-tris(trimethylsilyl)silene (1 ), and l-[bis-2 ,6 -(dimethylaminomethyl)phenyl]-l,2 ,2 -tris(trimethylsilyl)silene 2, were studied by 2 9 Si and C NMR spectroscopy, using polarization transfer techniques in order to determine coupling constants V (2 9 Si,2 9 Si) in = 1,2, 3) and '/ ( 2 9 Si,l3 C) together with is...

2017
Daniel M. Dawson Robert F. Moran Sharon E. Ashbrook

NMR crystallography has recently been applied to great effect for silica zeolites. Here we investigate whether it is possible to extend the structural information available from routine NMR spectra via a simple structure-spectrum relationship. Unlike previous empirically derived relationships that have compared experimental crystal structures for (often disordered) silicates with experimental N...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شیراز - دانشکده علوم 1391

in this thesis, we exploit a simple and suitable method for immobilization of copper(ii) complex of 4?-phenyl-terpyridine on activated multi-walled carbon nanotubes [amwcnts-o-cu(ii)-phtpy]. this nanostructure was characterized by various physico-chemical techniques. to ensure the efficiency and fidelity of copper species, the implementation of three-component strategies in click-chemistry all...

Influence of Aluminum, Gallium, Indium- Doping on the Boron-Nitride Nanotubes (BNNTs) investigated with density functional theory (DFT) and Hartreefock (HF) methods. For this purpose, the chemical shift of difference atomic nucleus was studied using the gauge included atomic orbital (GIAO) approch. In the following, structural parameter values, electrostatic potential, thermodynamic parameters,...

Journal: :journal of physical & theoretical chemistry 2007
f. naderi m. monajjemi m. yari k. bakhshi

quaternary ammonium compounds (qacs) are employed both as disinfectants for manual processing lines and surfaces in the food industry, and in human medicine area. qacs also cause cell death by protein denaturation . one of the qac is cetyl trimethyl ammonium bromide (ctab) that appears to rapture the cell membrane. the primary site of action of ctab has been suggested to be the lipid components...

2008
Peter Hoppe Jan Leitner Bradley S. Meyer Lih-Sin The Maria Lugaro Sachiko Amari

We report the discovery of a presolar SiC grain (KJB2-11-17-1) with unusual Si-isotopic composition. The grain has 29Si/28Si = 1.63 × solar, 30Si/28Si = 0.82 × solar, 12C/13C = 265 ( = 3 × solar), and evidence for the presence of radiogenic 44Ca from the decay of 44Ti. A comparison of these isotopic signatures with stellar models suggests an origin in a 15 M Type II supernova. It is possible to...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه صنعتی اصفهان - دانشکده شیمی 1389

in this project, some new polyaspartimides, (pas)s, have been synthesized form michael addition reaction between new synthetic bismaleimide (bmi) and some aromatic diamines. a characteristic property of this polyaspartimides is a pendent carboxylic group, which introduced to these polymers from new bismaleimide. bismaleimides (bmi) is one of the interesting compounds, which can be self-polymeri...

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