Spectroscopic and first principle DFT+eDMFT study of complex structural, electronic, and vibrational properties of M2Mo3O8 ( M=Fe , Mn) polar magnets
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99 GENERAL AND MISCELLANEOUS↗
Engineering topics
Gao, B.
Publications and source records attributed to Gao, B..
New Fe 59 Stellar Decay Rate with Implications for the Fe 60 Radioactivity in Massive Stars
The discrepancy between observations from γ-ray astronomy of the 60 Fe/ 26 Al γ-ray flux ratio and recent calculations is an unresolved puzzle in nuclear astrophysics. The stellar β-decay rate of 59 Fe is one of the major nuclear uncertainties impeding us from a precise prediction. The important Gamow-Teller strengths from the low-lying states in 59 Fe to the 59 Co ground state are measured for the first time using the exclusive measurement of the 59 Co(t,3He+γ) 59 Fe charge-exchange reaction. The new stellar decay rate of 59 Fe is a factor of 3.5±1.1 larger than the currently adopted rate at T=1.2 GK. Stellar evolution calculations show that the 60 Fe production yield of an 18 solar mass star is decreased significantly by 40% when using the new rate. Our result eliminates one of the major nuclear uncertainties in the predicted yield of 60 Fe and alleviates the existing discrepancy of the 60 Fe/ 26 Al ratio.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
From One- to Two-Magnon Excitations in the S = 3 / 2 Magnet β - CaCr 2 O 4
Here, we apply neutron spectroscopy to measure the magnetic dynamics in the S = 3 / 2 magnet β-CaCr 2 O 4 ( T N = 21 K ). The low-energy fluctuations, in the ordered state, resemble large- S linear spin waves from the incommensurate ground state. However, at higher energy transfers, these semiclassical and harmonic dynamics are replaced by an energy and momentum broadened continuum of excitations. Applying kinematic constraints required for energy and momentum conservation, sum rules of neutron scattering, and comparison against exact diagonalization calculations, we show that the dynamics at high-energy transfers resemble low- S one-dimensional quantum fluctuations. β-CaCr 2 O 4 represents an example of a magnet at the border between classical Néel and quantum phases, displaying dual characteristics.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
A Proposed Update to the Solar Irradiance Spectrum Used in LOWTRAN and MODTRAN
The calibrated upwelling radiance spectra measured by AVIRIS are increasingly being analyzed with radiative transfer codes. Analysis of AVIRIS data with the LOWTRAN and MODTRAN radiative transfer codes has led to indications of an error in the solar irradiance spectra used by these codes. This paper presents evidence for the error and a proposed update to the solar irradiance spectra used by LOWTRAN and MODTRAN.
AVIRIS↗
Remote Sensing of Smoke, Clouds, and Fire Using AVIRIS Data
POSTER - We describe our studies of smoke, clouds, and fire using high spatial and spectral resolution data acquired with the NASA/JPL Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) (Vand, 1987; Green et al., 1993)
AVIRIS↗