1,946 research outputs found
FAST polarization mapping of the SNR VRO 42.05.01
We have obtained the polarization data cube of the VRO 42.05.01 supernova
remnant at 1240 MHz using the Five-hundred-meter Aperture Spherical radio
Telescope (FAST). Three-dimensional Faraday Synthesis is applied to the FAST
data to derive the Faraday depth spectrum. The peak Faraday depth map shows a
large area of enhanced foreground RM of ~60 rad m-2 extending along the
remnant's "wing" section, which coincides with a large-scale HI shell at -20
km/s. The two depolarization patches within the "wing" region with RM of 97 rad
m-2 and 55 rad m-2 coincide with two HI structures in the HI shell. Faraday
screen model fitting on the Canadian Galactic Plane Survey (CGPS) 1420 MHz
full-scale polarization data reveals a distance of 0.7-0.8d_{SNR} in front of
the SNR with enhanced regular magnetic field there. The highly piled-up
magnetic field indicates that the HI shell at -20 km/s could originate from an
old evolved SNR.Comment: 9 pages, 8 figures, accepted by Ap
Thermal Analysis and Characterization of Polystyrene Initiated by Benzoyl Peroxide
PresentationBased on the complexity of the polystyrene polymerization mechanism initiated by benzoyl peroxide (BPO), the thermal risk of the reaction process was estimated using thermal analysis and characterization. The polymerization process was thermally analysed using an adiabatic rate calorimeter and differential scanning calorimeter. The results demonstrated that the onset reaction temperature, adiabatic temperature rise, and maximum temperature of the synthesis reaction of BPO-initiated polymerization were lower than those of thermos initiated polymerization. Moreover, nuclear magnetic resonance imaging, gel permeation chromatography, and Fourier transform infrared spectrometry were used to characterize the polymerization products obtained under the two initiation conditions. The polystyrene obtained using the two initiation methods had the same hydrogen structure; however, their molecular weight and distribution uniformity differed considerably, and the BPO-initiated process was discovered to include the effects of the thermos initiated process. Moreover, the free radicals produced by BPO decomposition participated in the chain reaction of polystyrene polymerization, accelerated instantaneous grain growth, and promoted the formation of short- chain polystyrene. In summary, the BPO-initiated polymerization process exhibited the desired thermal safety characteristics and has potential for practical use
(Z)-2-Hydroxy-3-(4-methoxyphenyl)acrylic acid
In the structure of the title compound, C10H10O4, inversion dimers linked by pairs of O—H⋯O hydrogen bonds link the carboxylic acid groups. Further O—H⋯O links cross-link the dimers into sheets running along the b-axis direction
(Z)-2-Acetamido-3-(4-chlorophenyl)acrylic acid
In the title compound, C11H10ClNO3, the molecule consists of a benzene ring and an acetamidoacrylic acid unit on opposite sides of the C=C double bond. In the crystal, intermolecular O—H⋯O and N—H⋯O hydrogen bonds assemble the molecules into infinite two-dimensional ribbons. These ribbons are linked into a network by intermolecular C—H⋯π contacts
Nonlinear Floquet dynamics of spinor condensates in an optical cavity: Cavity-amplified parametric resonance
We investigate Floquet dynamics of a cavity-spinor Bose-Einstein condensate
coupling system via periodic modulation of the cavity pump laser. Parametric
resonances are predicted and we show that due to cavity feedback-induced
nonlinearity the spin oscillation can be amplified to all orders of resonance,
thus facilitating its detection. Real-time observation on Floquet dynamics via
cavity output is also discussed
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