نتایج جستجو برای: 27al and 35cl nqr

تعداد نتایج: 16827433  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت مدرس 1377

یکی از روشهای مهم برای شناسایی ترکیبات شیمیایی اسپکتروسکوپی رزوناس چهار قطبی هسته می باشد که می توان از داده های طیف اسپکتروسکوپی ساختار فضایی و الکترونی مولکول را تعیین کرد ولی تهیه طیف نیاز به صرف وقت و هزینه زیاد می باشد لذا توسه یک روش برای پیش بینی داده های nqr ضروری و مفید می باشد. در این پروژه وابستگی فرکانس چهار قطبی هسته و پارامتر ضد تقارن گرادیان میدان الکترویکی در هسته های اتم برم و ...

Journal: :Journal of the American Chemical Society 2004
Trong-On Do Andrei Nossov Marie-Anne Springuel-Huet Celine Schneider Jeremy L Bretherton Colin A Fyfe Serge Kaliaguine

Ultrahigh-field 27Al MAS and MQMAS NMR and 129Xe NMR were used to characterize the zeolite-coated SBA-15 materials. This study shows evidence that zeolite nanoclusters are coated on the mesopore surface of SBA-15. These techniques are useful for the detection of zeolite nanoclusters and different aluminum environments in zeolite/aluminosilicate composites, which are difficult or even impossible...

Journal: :Magnetic Resonance in Chemistry 2021

Heteronuclear multiple-quantum coherence (HMQC) pulse sequences for establishing heteronuclear correlation in solid-state nuclear magnetic resonance (NMR) between 35Cl and 1H nuclei chloride salts under fast (60 kHz) magic-angle spinning (MAS) at high field (a Larmor frequency of 850 MHz) are investigated. Specifically, recoupling the 35Cl–1H dipolar interaction using rotary with phase inversio...

Density functional theory methods(DFT) and natural bond orbital (NBO) analysis were used to investigate the effects of isomerism and side chain mutation at a microscopic level on the stability, binding energy and NMR/NQR tensors of structural isomers, L- methionylasparagine (Met-Asn) and L- asparagylmethionine (Asn-Met) in the gas phase. The results represented that the isomerism and side chain...

Journal: :Clinical science 1997
K W Schönholzer R A Sutton V R Walker V Sossi M Schulzer C Orvig E Venczel R R Johnson D Vetterli B Dittrich-Hannen P Kubik M Suter

1. Until recently studies of intestinal aluminium absorption used pharmacological amounts of stable 27Al. 2. To examine the intestinal absorption of trace amounts of different chemical compounds of aluminium, in the present study we have employed the long half-life isotope of aluminium, 26Al, and accelerator mass spectrometry. Trace amounts of 26Al (2.7-12.1 ng) as the hydroxide, citrate, citra...

Journal: :Nanoscale 2010
Sekher Reddy Ghanta Krishnamurthi Muralidharan

The reduction of aluminium trichloride by lithium aluminium hydride in the presence of poly(vinylpyrrolidone) or poly(methylmethacrylate) in mesitylene yielded nano aluminium particles in the matrices of respective polymers. Solution phase synthesis methodology was used successfully to produce composites of various Al/polymer ratios. The composites were characterized by powder XRD patterns and ...

2012
Mehran Aghaie

Density functional theory (DFT) calculations were performed to compute nitrogen-14 and boron-11 nuclear quadrupole resonance (NQR) spectroscopy parameters in the representative model of armchair boron nitride nanotube (BNNT) for the first time. The considered model consisting of 1 nm length of H-capped (5, 5) single-wall BNNT were first allowed to fully relax and then the NQR calculations were ...

2009
Mehran Aghaie

Density functional theory (DFT) calculations were performed to compute nitrogen-14 and boron-11 nuclear quadrupole resonance (NQR) spectroscopy parameters in the representative model of armchair boron nitride nanotube (BNNT) for the first time. The considered model consisting of 1 nm length of H-capped (5, 5) single-wall BNNT were first allowed to fully relax and then the NQR calculations were ...

2012
Detlef Brinkmann

This paper discusses recent NQR/NMR studies performed on Y-Ba-Cu-0 superconductors at the University of Zürich. The work is concerned with normal state properties which are still controversial, for instance the spin-gap effect, i.e. the opening of a pseudo gap in the electron spin excitation spectrum at a temperature 7*, which lies above Tc. We will report on the detection of "anomalies" which ...

In this research, the interactions of HCN gas with pristine, Ga-, N- and GaN-doped of boron phosphide nanotube (BPNTs) were investigated by using density function theory (DFT). The structure, electrical and NQR parameters, quantum descriptors involving energy gap, global hardness, global softness, electrophilicity, electronic chemical potential and electronegativity were calculated. The adsorpt...

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