نتایج جستجو برای: nmr shielding

تعداد نتایج: 67435  

Journal: :Magnetochemistry 2023

This review represents a compendium of computational studies relativistic effects on the NMR chemical shifts light nuclei caused by presence heavy main group p-block elements in molecules. The narration starts from brief discussion theories and quantum methods for calculation at level electronic theory. part contains survey calculations shielding constants most popular NMR-active such as 1H, 13...

Journal: :jentashapir journal of health research 0
vahid karami department of medical physics, school of medicine, ahvaz jundishapur university of medical sciences, ahvaz, ir iran mansour zabihzadeh department of medical physics, school of medicine, ahvaz jundishapur university of medical sciences, ahvaz, ir iran; department of radiotherapy and radiation oncology, golestan hospital, ahvaz jundishapur university of medical sciences, ahvaz, ir iran; department of medical physics, school of medicine, ahvaz jundishapur university of medical sciences, 61357-33118, ahvaz, ir iran. tel: +98-9125032283, fax: +98-6133332066 mehrdad gholami department of medical physics, school of para medicine sciences, lorestan university of medical sciences, khorramabad, ir iran

conclusions comprehensive protection programs with on-the-job training courses for staff members are strongly recommended, as well as, the provision of radiological shields and gonad shielding protocols in radiology departments to reduce the patient’s radiation dose during radiological examinations. materials and methods a retrospective, observational cross-sectional study on the application of...

2012
Suvi Ikäläinen Juha Vaara Lauri Halonen Markku Räsänen

Theoretical examination of traditional nuclear magnetic resonance (NMR) parameters as well as novel quantities related to magneto-optic phenomena is carried out in this thesis for a collection of organic molecules. Electronic structure methods are employed, and reliable calculations involving large molecules and computationally demanding properties are made feasible through the use of completen...

2005
MICHAEL FECHTELKORD FRANK STIEF JOSEF-CHRISTIAN BUHL

Static and Na MAS and H MAS NMR experiments at temperatures down to 100 K as well as high temperature static and Na MAS NMR experiments up to 873 K were carried out to study the dynamics of the sodium cation in nitrate cancrinite. In addition, X-ray powder data were recorded at 296 K and 673 K to obtain information about long-range order changes in the structure. Low temperature Na NMR experime...

M. Heshmat M. Monajjemi M. Sadegizadeh S. Irani S.M Atyabi T. Nejadsattari

P53 is one of the gene that has important role in human cell cycle and in the human cancers too.Models of codon substitution make it possible to separate mutational biases in the DNA fromselective constraints on the protein, and offer a great advantage over amino acid models forunderstanding the evolutionary process of proteins and protein-coding DNA sequences. In thiswork, we investigated abou...

Journal: :The journal of physical chemistry. B 2009
Licínia L G Justino M Luísa Ramos Paulo E Abreu Rui A Carvalho Abilio J F N Sobral Ullrich Scherf Hugh D Burrows

Relationships have been obtained between intermonomer torsional angle and NMR chemical shifts ((1)H and (13)C) for isolated chains of two of the most important poly(9,9-dialkylfluorenes), poly[9,9-bis(2-ethylhexyl)fluorene-2,7-diyl] (PF2/6) and the copolymer poly(9,9-dioctylfluorene-co-[2,1,3]benzothiadiazole-4,7-diyl) (F8BT), using DFT calculations. The correlations provide a model for NMR spe...

Abstract The structural and electrostatic properties of the single-walled two representative (8, 0) zigzag and (4, 4) armchair models of pristine and GaAs-doped on boron phosphide nanotubes (BPNTs) was investigated by calculating the nuclear magnetic resonance tensors and with performing the density function theory. The geometrical structures of all representative pristine and GaAs-doped mode...

Journal: :Magnetochemistry 2023

In this article, we delve into the intricate behavior of electronic mechanisms underlying NMR magnetic shieldings σ in molecules containing heavy atoms, such as cadmium, platinum, and mercury. Specifically, explore PtXn−2 (X = F, Cl, Br, I; n 4, 6) XCl2Te2Y2H6 Cd, Hg; Y N, P) molecular systems. It is known that leading responsible for relativistic effects on are well characterized by linear res...

Journal: :Inorganic chemistry 2007
Masato Kujime Takuya Kurahashi Masaaki Tomura Hiroshi Fujii

63Cu NMR spectroscopic studies of copper(I) complexes with various N-donor tridentate ligands are reported. As has been previously reported for most copper(I) complexes, 63Cu NMR signals, when acetonitrile is coordinated to copper(I) complexes of these tridentate ligands, are broad or undetectable. However, when CO is bound to tridentate copper(I) complexes, the 63Cu NMR signals become much sha...

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