نتایج جستجو برای: nuclear magnetic resonance spectroscopy
تعداد نتایج: 750760 فیلتر نتایج به سال:
Accelerated multi-dimensional NMR spectroscopy is a prerequisite for high-throughput applications, studying short-lived molecular systems and monitoring chemical reactions in real time. Non-uniform sampling is a common approach to reduce the measurement time. Here, a new method for high-quality spectra reconstruction from non-uniformly sampled data is introduced, which is based on recent develo...
Simultaneous analysis of explosives to identify, determine the purity and eliminate environmental pollution requires rapid, simple and cheap methods. Spectrophotometries method (UV-Vis), high-field proton nuclear magnetic resonance (1H-NMR), Raman spectroscopy and near infrared (NIR) are common methods that are applicable in two ways of direct and indirect in simultaneous analysis. In this poin...
A new approach for accurate quantitative determination by fluorine nuclear magnetic resonance ( 19 F NMR) spectroscopy is presented and discussed. 19 F NMR spectroscopy has similar properties to 1 H NMR spectroscopy except for the wide chemical shift dispersion, which is the main difference between the two techniques. The off-resonance effect, which is caused by the chemical shift difference be...
adsorption of co2 on the surface of single-wall zigzag (5,0) and armchair (4,4) carbon nanotubes (swcnts) were studied through using density functional theory (dft) calculations. optimizations of geometric were performed at the b3pw91 level of 6-311++g** method standard basis set using gaussian 03 package of program [1]. structural models were optimized and adsorption energies, band gap, charge...
introduction radiofrequency planar microcoils are used to increase the resolution of magnetic resonance images of small samples. in this study, we aimed to design and fabricate a spiral planar microcoil constructed on a double-sided printed circuit board (pcb). it has four rings with an internal diameter of 241 microns tuned and matched at 63.8 mhz. materials and methods to achieve the maximum ...
Nuclear magnetic resonance (NMR) spectroscopy is a powerful technique for structural studies of chemical compounds and biomolecules such as DNA and proteins. Since the NMR signal sensitively reflects the chemical environment and the dynamics of a nuclear spin, NMR experiments provide a wealth of structural and dynamic information about the molecule of interest at atomic resolution. In general, ...
background: to analyze the characteristic performance of magnetic resonance spectroscopy (mrs) and susceptibility weighted imaging (swi) in cerebral alve-olar echinococcosis (cae). methods: we retrospectively analyzed 10 clinical-identified cae cases mr per-formance, and summarized the mrs and swi performance of cae. results: the 10 cases of cae all had the history of primary hae, among who 6 c...
background: distinction between radiation necrosis and recurrence of intraparenchymal tumors is necessary to select the appropriate treatment, but it is often difficult based on imaging features alone. we developed an algorithm for analyzing magnetic resonance spectroscopy (mrs) findings and studied its accuracy in differentiation between radiation necrosis and tumor recurrence. m e t hod s : ...
in this research, the microstructural of low molecular weight 1,2-polybutadiene (1,2-pbd) was conducted by 1h and 13c nuclear magnetic resonance spectroscopy (nmr) to determine the isomeric contents of 1,4-cis, 1,4-trans and 1,2-vinyl in 1,2-pbd polymer structures. number average molecular weight for low molecular weight 1,2-pbd was measured by nmr techniques and the results were compared with ...
microstructural investigation of low molecular weight 1,4-polybutadiene (1,4-pbd) was studied by 1h and 13c nuclear magnetic resonance spectroscopy (nmr). the isomer contents of 1,4-cis, 1,4-trans and 1,2- vinyl in polybutadiene microstructure were determined. the number average molecular weight for low molecular weight polybutadiene was measured by nmr techniques and comparison was made with g...
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