1,967 research outputs found
Multiferroic properties of an \aa kermanite SrCoSiO single crystal in high magnetic fields
The magnetic and dielectric properties of \aa kermanite SrCoSiO
single crystals in high magnetic fields were investigated. We have observed
finite induced electric polarization along the c axis in high fields, wherein
all Co spins were forcibly aligned to the magnetic field direction. Existence
of the induced polarization in the spin-polarized state accompanied with the
finite slope in the magnetization curve suggests the possible role of the
orbital angular momenta in the excited states as its microscopic origin. The
emergence of the field-induced polarization without particular magnetic order
can be regarded as the magnetoelectric effects of the second order from the
symmetry point of view. A low magnetic field-driven electric polarization flip
induced by a rotating field, even at room temperature, has been successfully
demonstrated.Comment: 12 pages, 4 figure
Five-dimensional Monopole Equation with Hedge-Hog Ansatz and Abel's Differential Equation
We review the generalized monopole in the five-dimensional Euclidean space. A
numerical solution with the Hedge-Hog ansatz is studied. The Bogomol'nyi
equation becomes a second order autonomous non-linear differential equation.
The equation can be translated into the Abel's differential equation of the
second kind and is an algebraic differential equation.Comment: 4 pages, 4 figures, typos correcte
Helium, Oxygen, Proton, and Electron (HOPE) Mass Spectrometer for the Radiation Belt Storm Probes Mission
The HOPE mass spectrometer of the Radiation Belt Storm Probes (RBSP) mission (renamed the Van Allen Probes) is designed to measure the in situ plasma ion and electron fluxes over 4π sr at each RBSP spacecraft within the terrestrial radiation belts. The scientific goal is to understand the underlying physical processes that govern the radiation belt structure and dynamics. Spectral measurements for both ions and electrons are acquired over 1 eV to 50 keV in 36 log-spaced steps at an energy resolution ΔE FWHM/E≈15 %. The dominant ion species (H+, He+, and O+) of the magnetosphere are identified using foil-based time-of-flight (TOF) mass spectrometry with channel electron multiplier (CEM) detectors. Angular measurements are derived using five polar pixels coplanar with the spacecraft spin axis, and up to 16 azimuthal bins are acquired for each polar pixel over time as the spacecraft spins. Ion and electron measurements are acquired on alternate spacecraft spins. HOPE incorporates several new methods to minimize and monitor the background induced by penetrating particles in the harsh environment of the radiation belts. The absolute efficiencies of detection are continuously monitored, enabling precise, quantitative measurements of electron and ion fluxes and ion species abundances throughout the mission. We describe the engineering approaches for plasma measurements in the radiation belts and present summaries of HOPE measurement strategy and performance
Internal Energy of the Potts model on the Triangular Lattice with Two- and Three-body Interactions
We calculate the internal energy of the Potts model on the triangular lattice
with two- and three-body interactions at the transition point satisfying
certain conditions for coupling constants. The method is a duality
transformation. Therefore we have to make assumptions on uniqueness of the
transition point and that the transition is of second order. These assumptions
have been verified to hold by numerical simulations for q=2, 3 and 4, and our
results for the internal energy are expected to be exact in these cases.Comment: 9 pages, 4 figure
Classical gravitational spin-spin interaction
I obtain an exact, axially symmetric, stationary solution of Einstein's
equations for two massless spinning particles. The term representing the
spin-spin interaction agrees with recently published approximate work. The
spin-spin force appears to be proportional to the inverse fourth power of the
coordinate distance between the particles.Comment: six pages, no figures, journal ref:accepted for Classical and Quantum
Gravit
Magnetic and Dielectric Properties in Multiferroic Cu3Mo2O9 under High Magnetic Fields
The magnetic and dielectric properties under high magnetic fields are studied
in the single crystal of Cu3Mo2O9. This multiferroic compound has distorted
tetrahedral spin chains. The effects of the quasi-one dimensionality and the
geometrical spin frustration are expected to appear simultaneously. We measure
the magnetoelectric current and the differential magnetization under the pulsed
magnetic field up to 74 T. We also measure the electric polarization versus the
electric field curve/loop under the static field up to 23 T. Dielectric
properties change at the magnetic fields where the magnetization jumps are
observed in the magnetization curve. Moreover, the magnetization plateaus are
found at high magnetic fields.Comment: 6 pages, 3 figures, in press in JPS Conf. Proc. as a part of SCES2013
Proceeding
Probing a non-biaxial behavior of infinitely thin hard platelets
We give a criterion to test a non-biaxial behavior of infinitely thin hard
platelets of symmetry based upon the components of three order
parameter tensors. We investigated the nematic behavior of monodisperse
infinitely thin rectangular hard platelet systems by using the criterion.
Starting with a square platelet system, and we compared it with rectangular
platelet systems of various aspect ratios. For each system, we performed
equilibration runs by using isobaric Monte Carlo simulations. Each system did
not show a biaxial nematic behavior but a uniaxial nematic one, despite of the
shape anisotropy of those platelets. The relationship between effective
diameters by simulations and theoretical effective diameters of the above
systems was also determined.Comment: Submitted to JPS
On the low-temperature lattice thermal transport in nanowires
We propose a theory of low temperature thermal transport in nano-wires in the
regime where a competition between phonon and flexural modes governs the
relaxation processes. Starting with the standard kinetic equations for two
different types of quasiparticles we derive a general expression for the
coefficient of thermal conductivity. The underlying physics of thermal
conductance is completely determined by the corresponding relaxation times,
which can be calculated directly for any dispersion of quasiparticles depending
on the size of a system. We show that if the considered relaxation mechanism is
dominant, then at small wire diameters the temperature dependence of thermal
conductivity experiences a crossover from to -dependence.
Quantitative analysis shows reasonable agreement with resent experimental
results.Comment: 12 pages, 3 eps figure
Reduction of myocardial infarction by postischemic administration of the calpain inhibitor A-705253 in comparison to the Na(+)/H(+) exchange inhibitor Cariporide (R) in isolated perfused rabbit hearts
The calpain inhibitor A-705253 and the Na(+)/H(+) exchange inhibitor Cariporide (R) were studied in isolated perfused rabbit hearts subjected to 60 min occlusion of the ramus interventricularis of the left coronary artery (below the origin of the first diagonal branch), followed by 120 min of reperfusion. The inhibitors were added to the perfusion fluid solely or in combination at the beginning of reperfusion. Hemodynamic monitoring and biochemical analysis of perfusion fluid from the coronary outflow were performed. Myocardial infarct size and area at risk (transiently not perfused myocardium) were determined from left ventricular slices after a special staining procedure with Evans blue and 2,3,5-triphenyltetrazolium chloride. The infarcted area (dead myocardium) was 72.7 +/- 4.0% of the area at risk in untreated controls, but was significantly smaller in the presence of the inhibitors. The largest effect was observed with 10(-6) M A-705253, which reduced the infarcted area to 49.2 +/- 4.1% of the area at risk, corresponding to a reduction of 33.6%. Cariporide (R) at 10(-6) M reduced the infarct size to the same extent. The combination of both inhibitors, however, did not further improve cardioprotection. No significant difference was observed between the experimental groups in coronary perfusion, left ventricular pressure, heart rate, or in the release of lactate dehydrogenase and creatine kinase from heart muscle
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