Results 131 to 140 of about 736 (155)
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Radiofrequency encoded Only Parahydrogen SpectroscopY
Journal of Magnetic Resonance, 2021A new pulse sequence aimed to filter out NMR signals coming from thermally polarized protons in PHIP experiments based on the OPSY pulse sequence (Only Parahydrogen SpectroscopY) is presented. In analogy to OPSY, which removes thermal polarization by using a pair of magnetic field gradient pulses with an intensity ratio 1:2 and equal duration, the same
S, Bussandri +2 more
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Hyperpolarizing Water with Parahydrogen
ChemPhysChem, 2017AbstractStudies of water‐based systems are of fundamental interest for nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) as water is the most abundant and important medium for global living. Hence, increasing the polarization of water and dissolved compounds is particularly attractive for biomedical applications such as ...
Sören Lehmkuhl +6 more
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Heterogeneous Catalysis and Parahydrogen‐Induced Polarization
ChemPhysChem, 2021AbstractParahydrogen‐induced polarization with heterogeneous catalysts (HET‐PHIP) has been a subject of extensive research in the last decade since its first observation in 2007. While NMR signal enhancements obtained with such catalysts are currently below those achieved with transition metal complexes in homogeneous hydrogenations in solution, this ...
Ekaterina V. Pokochueva +3 more
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PIMC simulations of solid parahydrogen
Physical Review B, 1991We have evaluated the kinetic energy of the center of mass of solid parahydrogen at T=18.9 K, and four different densities, by means of path-integral Monte Carlo computer simulation, using the pairwise additive Lennard-Jones potential. The results have been compared with the available experimental neutron data of Herwig et al. [Phys. Rev.
, Zoppi, , Neumann
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Solid Parahydrogen Thickness Revisited
Applied Spectroscopy, 2019We report updated infrared (IR) absorption measurements on vapor-deposited cryogenic parahydrogen (pH2) solids that indicate a ≈10% systematic error in our previous approach for determining a pH2 solid's thickness (S. Tam and M.E. Fajardo. Appl. Spectrosc. 2001. 55(12): 1634-1644).
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Parahydrogen Conversion on Tungsten
Nature, 1940THIS reaction1 has been reinvestigated using a reaction tube containing a second short filament adjacent to the catalyst filament, so that adsorbed films on the latter might be detected by a measurement of their contact potential2. In this way it was shown that the filament in its most catalytically active state was free from adsorbed oxygen.
D. D. ELEY, E. K. RIDEAL
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Superplasticity of solid parahydrogen
Soviet Journal of Low Temperature Physics, 1984The plastic properties of single-crystal specimens of parahydrogen have been studied at helium temperatures. It was found that the plasticity increases sharply as the temperature is reduced to 1.8-2 K. The phenomenon of flow of sufficiently perfect p-H2 crystals under the force of gravity was observed.
L. A. Alekseeva, I. N. Krupskiĩ
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The microscopic dynamics of condensed parahydrogen
Applied Physics A: Materials Science & Processing, 2002We have measured the almost-pure incoherent scattering function of liquid and solid parahydrogen, using inelastic neutron scattering. The experiments were carried out on TOSCA, a time-of-flight, inverse-geometry, crystalanalyzer spectrometer, operating on the pulsed neutron source at ISIS (UK).
Celli M., Colognesi D., Zoppi M.
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Raman gain measurement in solid parahydrogen
Optics Letters, 2000We report a steady-state Raman gain measurement of the Q(1)(0) transition (v = 1 ? 0, J = 0 ? 0) in solid parahydrogen. We carry out measurements by pumping with a continuous-wave frequency-doubled YAG laser at 532 nm and observing the direct amplification of a probe-laser beam for the first Stokes transition at 683 nm.
M, Katsuragawa, K, Hakuta
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Isothermal compressibility of solid parahydrogen
Journal of Low Temperature Physics, 1970The method of the determination of isothermal compressibility of solid parahydrogen on the basis of dielectric constant measurements has been described. The data on isothermal compressibility of solid parahydrogen in the temperature range of 6–14.5°K and at pressures of 0–180 atm have been presented.
B. G. Udovidchenko, V. G. Manzhelii
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