نتایج جستجو برای: cpmas nmr

تعداد نتایج: 58833  

2012
Xianming Qing

In modern wireless communication systems, small circularly polarized microstrip antennas with good performance are desirable mainly at low microwave frequencies. The radio frequency identification (RFID) systems in the ultra-high frequency (UHF) band have gained much interest in many services [Finkenzeller2004]. The reader antenna is one of the important components in the RFID reader system and...

Journal: :Geoderma 2022

• Bulk SOC increased under long-term organic fertilization. No accumulated in the MAOM fraction (<6.3 µm) over a 36-year period. increase fertilization was solely attributed to labile POM fractions. oPOM-C contents are highly dynamic and depend on farming system. Agricultural management of soils has led severe losses soil matter (SOM), accompanied by an release CO 2 into atmosphere reduction fe...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت مدرس - دانشکده علوم پایه 1389

در قسمت اول رساله واکنش تشکیل کمپلکس یون تالیم با calix[4]crown-6 و سه مشتق دیگر آن با روشهای 203tl , 1h nmr مورد بررسی قرار گرفتند. همچنین کمپلکس یک هسته ای tlclo4 و 1,3-calix[4]bis-o-benzo-crown-6 در حالت جامد تهیه شد و ساختار بلوری x-ray آن تعیین گردید. سینتیک و مکانیسم تفکیک و تغییرات پیکربندی کمپلکس تالیم و calix[4]crown-6 با دینامیک 1h nmr مورد مطالعه قرار گرفت. یک منحنی محدب آرنیوس برای ...

Journal: :Talanta 2002
Anupama Goswami Ajai K Singh

A new chelating matrix has been prepared by immobilizing 1,8-dihydroxyanthraquinone (DHAQ) on silica gel modified with (3-aminopropyl)triethoxysilane. After characterizing the matrix with thermogravimetric analysis (TGA), cross polarization magic angle spinning (CPMAS) NMR and diffuse reflectance infrared fourier transformation (DRIFT) spectroscopy, it has been used to preconcentrate Pb(II), Cd...

2003
Zdenek Hanzálek

This article addresses the problem of the computation of instantaneous firing speed in Invariant Behavior state (IB-state) of Constant speed Continuous Petri Net (CCPN) with presence of actual conflicts. The adopted approach is based on polyhedral computations applied to specify an area of possible instantaneous firing speed. If the actual conflicts are resolved by global priorities, the instan...

2001
David Snyder Paul Driscoll Peter Domaille

Even though there were actually a number of established scientists in attendance, the meeting seemed to be geared toward graduate students and postdocs. Many of the presentations focused on giving advice about and descriptions of the process of structural determination. There was little actual discussion of either algorithms or biology, but many of the opinions were quite thought provoking and ...

Journal: :Molecules 2013
Ahmed Ashour Mohamed Amer Amani Marzouk Kuniyoshi Shimizu Ryuichiro Kondo Saleh El-Sharkawy

Phytochemical examination of corncob extracts led to the isolation of a new lignan identified as 7,7'-dihydroxy-3'-O-demethyl-4-methoxymatairesinol, together with seven known compounds, identified as β-sitosterol, β-sitosteryl-β-D-glucoside, 6β-hydroxy-campest-4-en-3-one, 5α,8α-epidioxyergosta-6,22-dien-3β-ol, tricin, kaempferol and p-coumaric acid. The isolated compounds were identified by one...

Journal: :Carbohydrate polymers 2010
Daniela Beccati Sucharita Roy Fei Yu Nur Sibel Gunay Ishan Capila Miroslaw Lech Robert J Linhardt Ganesh Venkataraman

The worldwide heparin contamination crisis in 2008 led health authorities to take fundamental steps to better control heparin manufacture, including implementing appropriate analytical and bio-analytical methods to ensure production and release of high quality heparin sodium product. Consequently, there is an increased interest in the identification and structural elucidation of unusually modif...

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