نتایج جستجو برای: parahydrogen

تعداد نتایج: 287  

2011
Dmitry Budker

Spectroscopy with conventional nuclear magnetic resonance (NMR) requires large, expensive, superconducting magnets cooled by liquid helium, like the one in the background. The Pines and Budker groups have demonstrated NMR spectroscopy with a device only a few centimeters high, using no magnets at all (foreground). A chemical sample in the test tube (green) is polarized by introducing hydrogen g...

2012
Feng Li Duc Ngo Jinkyu Yang Chiara Daraio

Related Articles Wave excitations of drifting two-dimensional electron gas under strong inelastic scattering J. Appl. Phys. 112, 083721 (2012) Phonon engineering in nanostructures: Controlling interfacial thermal resistance in multilayer-graphene/dielectric heterojunctions Appl. Phys. Lett. 101, 113111 (2012) Amplification of hippersound in graphene under external direct current electric field ...

1997
Takamasa Momose

The vibration-rotation states of a tetrahedral molecule in a field of D3h symmetry are studied by an extended group theory. Symmetry adapted rotational wave functions for the ground and the triply degenerate excited vibrational states are constructed. The crystal field potential is derived explicitly for a tetrahedral molecule in a hexagonal close-packed crystal. As an example, the rovibrationa...

2014
Roman V. Shchepin Aaron M. Coffey Kevin W. Waddell Eduard Y. Chekmenev

The synthetic protocol for preparation of 1-(13)C-phosphoenolpyruvate-d2, precursor for parahydrogen-induced polarization (PHIP) of 1-(13)C-phospholactate-d2, is reported. (13)C nuclear spin polarization of 1-(13)C-phospholactate-d2 was increased by >30,000,000-fold (5.75 mT) in water. The reported (13)C polarization level approaching unity (>15.6%), long lifetime of (13)C hyperpolarized 1-(13)...

Journal: :Magnetic resonance in chemistry : MRC 2008
Meike Roth Joachim Bargon Hans Wolfgang Spiess Achim Koch

Homogeneous hydrogenation of barbituric acid derivatives with parahydrogen yields a substantial increase of the (1)H NMR signals of the reaction products. These physiologically relevant compounds were hydrogenated at both ambient and elevated temperatures and pressures using a standard cationic rhodium catalyst. The resulting nonthermal nuclear spin polarization (hyperpolarization) is limited b...

2014
Aaron M. Coffey Kirill V. Kovtunov Danila A. Barskiy Igor V. Koptyug Roman V. Shchepin Kevin W. Waddell Ping He Kirsten A. Groome Quinn A. Best Fan Shi Boyd M. Goodson Eduard Y. Chekmenev

We demonstrate the feasibility of microscale molecular imaging using hyperpolarized proton and carbon-13 MRI contrast media and low-field (47.5 mT) preclinical scale (38 mm i.d.) 2D magnetic resonance imaging (MRI). Hyperpolarized proton images with 94 × 94 μm(2) spatial resolution and hyperpolarized carbon-13 images with 250 × 250 μm(2) in-plane spatial resolution were recorded in 4-8 s (large...

Journal: :Journal of the American Chemical Society 2012

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