46,074 research outputs found
Condensation of Cytidylic Acid in the Presence of Polyphosphoric Acid
Condensation of cytidylic acid in presence of polyphosphoric aci
Magnetic reconnection in plasma under inertial confinement fusion conditions driven by heat flux effects in Ohm's law
In the interaction of high-power laser beams with solid density plasma there
are a number of mechanisms that generate strong magnetic fields. Such fields
subsequently inhibit or redirect electron flows, but can themselves be advected
by heat fluxes, resulting in complex interplay between thermal transport and
magnetic fields.We show that for heating by multiple laser spots reconnection
of magnetic field lines can occur, mediated by these heat fluxes, using a fully
implicit 2D Vlasov-Fokker-Planck code. Under such conditions, the reconnection
rate is dictated by heat flows rather than Alfv\`enic flows. We find that this
mechanism is only relevant in a high plasma. However, the Hall
parameter can be large so that thermal transport is
strongly modified by these magnetic fields, which can impact longer time scale
temperature homogeneity and ion dynamics in the system
A Search for N2+ in Spectra of Comet C/2002C1 (Ikeya-Zhang)
We report low- and high-resolution spectra of comet C/2002 C1 (Ikeya-Zhang)
from McDonald Observatory. The comet had a well-developed ion tail including
CO+, CO2+, CH+, and H2O+. We used our high-resolution spectra to search for
N2+. None was detected and we placed upper limits on N2+/CO+ of 5.4 times
10^{-4}. N2+ was detected in the low-resolution spectra but we show that this
emission was probably telluric in origin (if cometary, we derive N2+/CO+ = 5.5
times 10^{-3}, still very low). We discuss the implications for the conditions
in the early solar nebula of the non-detection of N2+. These depend on whether
the H2O ice was deposited in the amorphous or crystalline form. If H2O was
deposited in its crystalline form, the detection of CO+ but not N2+ has
implications for H2O/H2 in the early solar nebula.Comment: Accepted for publication in ApJ (Letters) - 10 Sept 200
RAT0455+1305: another pulsating hybrid sdB star
RAT0455+1305 was discovered during the Rapid Temporal Survey which aims in
finding any variability on timescales of a few minutes to several hours. The
star was found to be another sdBV star with one high amplitude mode and
relatively long period. These features along with estimation of T_eff and log g
makes this star very similar to Balloon 090100001. Encouraged by prominent
results obtained for the latter star we have decided to perform white light
photometry on RAT0455+1305. In 2009 we used the 1.5m telescope located in San
Pedro Martir Observatory in Mexico. Fourier analysis confirmed the dominant
mode found in the discovery data, uncovered another peak close to the dominant
one, and three peaks in the low frequency region. This shows that RAT0455+1305
is another hybrid sdBV star pulsating in both p- and g-modes.Comment: Proceedings of The Fourth Meeting on Hot Subdwarf Stars and Related
Objects held in China, 20-24 July 2009. Accepted for publication in
Astrophysics & Space Scienc
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