Effect of a magnetic field on the fluorescence produced in irradiated anthracene solutions

1977 ◽  
Vol 55 (11) ◽  
pp. 2093-2101 ◽  
Author(s):  
R. S. Dixon ◽  
F. P. Sargent ◽  
V. J. Lopata ◽  
E. M. Gardy ◽  
B. Brocklehurst
Keyword(s):  
Magnetic Field ◽  
Fluorescence Intensity ◽  
Applied Magnetic Field ◽  
High Field ◽  
Spin Correlation ◽  
Hydrocarbon Solvents ◽  
Theoretical Predictions ◽  
High Fields ◽  
Ion Recombination ◽  
Gamma Irradiated

The effect of an applied magnetic field on the fluorescence from radiolytic ion recombination has been studied for anthracene in some hydrocarbon solvents. In pulse-irradiated anthracene (10−2 mol dm−3) in squalane, the fluorescence intensity following the pulse increases as a function of applied magnetic field in the range studied, 0 to 0.3 T (0 to 3000 G). At a constant magnetic field strength, the field-induced enhancement of the fluorescence intensity varies with time after the pulse. At high field strengths (0.3 T) the enhancement reaches a maximum of ∼45% about 50 ns after the pulse. Similar effects are observed in cyclohexane but the enhancement is smaller than that in squalane. In benzene solutions the effect is extremely small. These findings are confirmed by observations in continuously gamma-irradiated solutions. In gamma-irradiated solutions of anthracene (10−2 mol dm−3) in squalane, the fluorescence intensity increases with increasing magnetic field and approaches ∼13% enhancement at high fields (>0.1 T). The enhancement is smaller (∼3%) in cyclohexane and very small (<1%) in benzene solutions. 9,10-Dimethylanthracene gives a larger enhancement and anthracene-d10 a smaller enhancement than the parent anthracene at high fields. The results are in general agreement with recent theoretical predictions based on the effect of a magnetic field on the loss of spin correlation of geminate ions pairs prior to recombination.

scholarly journals Tunable Adhesion of a Bio-Inspired Micropillar Arrayed Surface Actuated by a Magnetic Field

2018 ◽  
Vol 86 (1) ◽  
Author(s):  
Xingji Li ◽  
Zhilong Peng ◽  
Yazheng Yang ◽  
Shaohua Chen
Keyword(s):  
Magnetic Field ◽  
Applied Magnetic Field ◽  
Magnetic Particles ◽  
Rotation Angle ◽  
Adhesion Force ◽  
Practical Applications ◽  
Section Shape ◽  
Theoretical Predictions ◽  
Large Elastic Deformation ◽  
The Difference

Bio-inspired functional surfaces attract many research interests due to the promising applications. In this paper, tunable adhesion of a bio-inspired micropillar arrayed surface actuated by a magnetic field is investigated theoretically in order to disclose the mechanical mechanism of changeable adhesion and the influencing factors. Each polydimethylsiloxane (PDMS) micropillar reinforced by uniformly distributed magnetic particles is assumed to be a cantilever beam. The beam's large elastic deformation is obtained under an externally magnetic field. Specially, the rotation angle of the pillar's end is predicted, which shows an essential effect on the changeable adhesion of the micropillar arrayed surface. The larger the strength of the applied magnetic field, the larger the rotation angle of the pillar's end will be, yielding a decreasing adhesion force of the micropillar arrayed surface. The difference of adhesion force tuned by the applied magnetic field can be a few orders of magnitude, which leads to controllable adhesion of such a micropillar arrayed surface. Influences of each pillar's cross section shape, size, intervals between neighboring pillars, and the distribution pattern on the adhesion force are further analyzed. The theoretical predictions are qualitatively well consistent with the experimental measurements. The present theoretical results should be helpful not only for the understanding of mechanical mechanism of tunable adhesion of micropillar arrayed surface under a magnetic field but also for further precise and optimal design of such an adhesion-controllable bio-inspired surface in future practical applications.

High-field liquid state NMR hyperpolarization: a combined DNP/NMRD approach

2014 ◽  
Vol 16 (35) ◽  
pp. 18781-18787 ◽  
Author(s):  
Petr Neugebauer ◽  
Jan G. Krummenacker ◽  
Vasyl P. Denysenkov ◽  
Christina Helmling ◽  
Claudio Luchinat ◽  
...  
Keyword(s):  
Magnetic Field ◽  
High Magnetic Field ◽  
Dynamic Nuclear Polarization ◽  
Liquid State ◽  
High Field ◽  
Nuclear Polarization ◽  
Nmr Relaxation ◽  
Relaxation Dispersion ◽  
Liquid Solutions ◽  
High Fields

Dynamic nuclear polarization and NMR relaxation dispersion measurements have been performed on liquid solutions of TEMPOL radicals in solvents with different viscosities at a high magnetic field of 9.2 T. The results indicate that fast dynamics significantly contribute to DNP enhancements at high fields.

MAGNETO-OPTICAL ROTATION IN VERY HIGH FIELDS

1960 ◽  
Vol 38 (7) ◽  
pp. 941-944 ◽  
Author(s):  
Richard Stevenson
Keyword(s):  
Magnetic Field ◽  
High Field ◽  
Optical Rotation ◽  
Field Limit ◽  
Electron Theory ◽  
Important Data ◽  
Kerr Rotation ◽  
High Fields ◽  
The Magnetic Field ◽  
Very High

Magneto-optical rotation by transmission through or reflection from solids is examined by the classical free electron theory, with the view of taking such a measurement using fields in the megagauss range. In general the rotation is a markedly non-linear function of the magnetic field, and in some cases can change in sign as the field increases. For very low fields the rotation varies directly with B, but in the high field limit the rotation varies inversely with the field. For substances in which the intercollision time of the electron is small, measurements of the Kerr rotation (i.e. by reflection) will give the electron mobility as a function of the magnetic field, and thus will give important data which can be used in conjunction with high field magnetoresistance experiments.

scholarly journals Evaluation of Exchange and Anisotropy Constants of Molecular Species from High Field Mössbauer Spectra

1998 ◽  
Vol 51 (2) ◽  
pp. 363
Author(s):  
J. D. Cashion ◽  
S. R. Shannon
Keyword(s):  
Magnetic Field ◽  
Molecular Species ◽  
Applied Magnetic Field ◽  
High Field ◽  
Mössbauer Spectra ◽  
Molecular Field ◽  
Field Equations ◽  
Mossbauer Spectra ◽  
Range Of Values

The molecular field equations for the allowed spin directions for dimer and trimer molecular species have been solved numerically for a range of values of the exchange and anisotropy interactions and of the applied magnetic field. The results may be used for the evaluation of the exchange and anisotropy constants from high field Mössbauer spectra or for selecting the best conditions for proposed experiments in order to determine these parameters.

Magnetic Properties of Superconducting GdBa2Cu3O6+δat Low Temperature and High Field

1987 ◽  
Vol 99 ◽  
Author(s):  
C. Y. Huang ◽  
Y. Shapira ◽  
P. H. Hor ◽  
R. L. Meng ◽  
C. W. Chu
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
Magnetic Properties ◽  
Low Temperature ◽  
Temperature Dependence ◽  
High Field ◽  
Spin Subsystem ◽  
High Fields ◽  
Very High ◽  
Canted Phase

ABSTRACTThe magnetization of antiferromagnetic superconducting GdBa2Cu3O6+δ has been measured for ∼1.5 < T ≤4.2 K for magnetic fields up to ∼20 T. We found that all Gd3+ spins are nearly parallel at very high fields, and that this saturated spin subsystem coexists with superconductivity. Below the Neel temperature, 2.22 K, we observed the transition from the “canted” phase to the paramagnetic phase by the application of a high magnetic field. The temperature dependence of this phase transition is also reported.

Magnetic field effect on the fluorescence from γ-irradiated solutions of perfluorocarbons

1979 ◽  
Vol 57 (23) ◽  
pp. 3023-3027 ◽  
Author(s):  
Robert Smith Dixon ◽  
Vincent John Lopata
Keyword(s):  
Magnetic Field ◽  
Fluorescence Intensity ◽  
Field Effect ◽  
Hyperfine Coupling ◽  
Fluorescence Enhancement ◽  
Relative Proportion ◽  
Magnetic Field Effect ◽  
Radical Ions ◽  
Field Independent ◽  
High Fields

The effect of an applied magnetic field on the fluorescence from γ-irradiated solutions of perfluorobiphenyl and perfluoronaphthalene has been measured in various solvents. In all the solvents used (cyclohexane, squalane, isooctane) the fluorescence intensity increases with increasing field and tends towards a plateau at high fields (>0.1 T). At low fields, the fluorescence enhancement is smaller for the perfluorocarbons than for the parent hydrocarbons, due to the larger electron–nuclear hyperfine coupling and broader spread of the hyperfine levels in the radical ions of the perfluorocarbons. At high fields the fluorescence enhancement is also smaller for the perfluorocarbons than for the parent hydrocarbons, indicating a larger relative proportion of prompt (field-independent) fluorescence for the perfluorocarbons than for the parent hydrocarbons.

Microstructure of Bidisperse Ferrofluids in a Monolayer

2012 ◽  
Vol 190 ◽  
pp. 625-628 ◽  
Author(s):  
A. Dobroserdova ◽  
E. Minina ◽  
J.J. Cerdà ◽  
C. Holm ◽  
S. Kantorovich
Keyword(s):  
Magnetic Field ◽  
Molecular Dynamic Simulation ◽  
Dynamic Simulation ◽  
Applied Magnetic Field ◽  
Simulation Data ◽  
Theoretical Predictions ◽  
Ring Structures ◽  
Bulk System ◽  
The One ◽  
Good Agreement

In the present study we briefly analyze the cluster structures observed in the model bidisperse ferrofluid constrained in quasi-2D (q2D) layer in the absence of an externally applied magnetic field. We use a combination of a DFT approach and molecular dynamic simulation to quantitatively describe various chain and ring structures and their equilibrium area fractions. We also show that to reach a good agreement between simulation data and theoretical predictions in q2D geometry in theory one needs to allow for more possible chain configurations than in the bulk system. We provide preliminary explanations why the microstructure of bulk bidisperse ferrofluids differs noticeably from the one in q2D layer.

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