609 research outputs found
Ard v. Ard, 395 So. 2d 586 (Fla. 1st Dist. Ct. App. 1981)
Torts-PARENTAL IMMUNITY-THE FIRST DISTRICT DECLINES TO ADOPT THE DOCTRINE OF PARENTAL IMMUNIT
Diffraction-limited spatial resolution of circumstellar shells at 10 microns
A new spatial array instrument provided diffraction-limited mid-infrared intensity profiles of the type-M supergiant stars alpha Orionis and alpha Scorpii, both of which are known to exhibit excess 10 microns radiation due to the presence of circumstellar dust shells. In the case of alpha Ori, there is a marked asymmetry in the dust distribution, with peak intensity of dust emission a distance of 0.9 inches from the star
Quantum Electrical Dipole in Triangular Systems: a Model for Spontaneous Polarity in Metal Clusters
Triangular symmetric molecules with mirror symmetry perpendicular to the
3-fold axis are forbidden to have a fixed electrical dipole moment. However, if
the ground state is orbitally degenerate and lacks inversion symmetry, then a
``quantum'' dipole moment does exist. The system of 3 electrons in D_3h
symmetry is our example. This system is realized in triatomic molecules like
Na_3. Unlike the fixed dipole of a molecule like water, the quantum moment does
not point in a fixed direction, but lies in the plane of the molecule and takes
quantized values +/- mu_0 along any direction of measurement in the plane. An
electric field F in the plane leads to a linear Stark splitting +/- mu_0 F}. We
introduce a toy model to study the effect of Jahn-Teller distortions on the
quantum dipole moment. We find that the quantum dipole property survives when
the dynamic Jahn-Teller effect is included, if the distortion of the molecule
is small. Linear Stark splittings are suppressed in low fields by molecular
rotation, just as the linear Stark shift of water is suppressed, but will be
revealed in moderately large applied fields and low temperatures. Coulomb
correlations also give a partial suppression.Comment: 10 pages with 7 figures included; thoroughly revised with a new
coauthor; final minor change
Stern-Gerlach deflection of field-free aligned paramagnetic molecules
The effects of laser-induced prealignment on the deflection of paramagnetic
molecules by inhomogeneous static magnetic field are studied. Depending on the
relevant Hund's coupling case of the molecule, two different effects were
identified: either suppression of the deflection by laser pulses (Hund's
coupling case (a) molecules, such as ClO), or a dramatic reconstruction of the
broad distribution of the scattering angles into several narrow peaks (for
Hund's coupling case (b) molecules, such as O2 or NH). These findings are
important for various applications using molecular guiding, focusing and
trapping with the help of magnetic fields
Velocity-selective resonance dips in the probe absorption spectra of Rb D2 transitions induced by a pump laser
We report experimental observation of velocity-selective resonances in the
Doppler-broadened probe absorption spectra of 85Rb and 87Rb D2 transitions in
the presence of a strong copropagating pump laser locked to a frequency within
the Doppler profile of the transition. The set of three dips having the
separation of allowed hyperfine transitions can be moved along the Doppler
profile by tuning the pump laser frequency indicating a resonance between the
pump laser frequency and the velocity shifted probe laser frequency.Comment: 7 pages, 4 figure
On spin-rotation contribution to nuclear spin conversion in C_{3v}-symmetry molecules. Application to CH_3F
The symmetrized contribution of E-type spin-rotation interaction to
conversion between spin modifications of E- and A_1-types in molecules with
C_{3v}-symmetry is considered. Using the high-J descending of collisional
broadening for accidental rotational resonances between these spin
modifications, it was possible to co-ordinate the theoretical description of
the conversion with (updated) experimental data for two carbon-substituted
isotopes of fluoromethane. As a result, both E-type spin-rotation constants are
obtained. They are roughly one and a half times more than the corresponding
constants for (deutero)methane.Comment: 13 pages with single-spacing, REVTeX, no figures, accepted for
publication in <J. Phys. B
Surface temperature measurements using a thin film thermal array
A thin film device was designed and fabricated to measure surface temperatures. An array of eight integrated thermal sensors are mounted on a 0.002 inch (0.05 mm) Kapton film and multiplexed to obtain an area thermal measurement. The device was tested on a flat plate airfoil and demonstrated a temperature variation of 0.55 C maximum and 0.05 C minimum compared to embedded thermocouples. Future improvements are also discussed
Near and mid-IR sub-arcsecond structure of the dusty symbiotic star R Aqr
The results of a high-resolution interferometric campaign targeting the
symbiotic long-period variable (LPV) R~Aqr are reported. With both
near-infrared measurements on baselines out to 10m and mid-infrared data
extending to 32m, we have been able to measure the characteristic sizes of
regions from the photosphere of the LPV and its extended molecular atmosphere,
out to the cooler circumstellar dust shell. The near-infrared data were taken
using aperture masking interferometry on the Keck-I telescope and show R~Aqr to
be partially resolved for wavelengths out to 2.2 microns but with a marked
enlargement, possibly due to molecular opacity, at 3.1 microns. Mid-infrared
interferometric measurements were obtained with the U.C. Berkeley Infrared
Spatial Interferometer (ISI) operating at 11.15 microns from 1992 to 1999.
Although this dataset is somewhat heterogeneous with incomplete coverage of the
Fourier plane and sampling of the pulsation cycle, clear changes in the
mid-infrared brightness distribution were observed, both as a function of
position angle on the sky and as a function of pulsation phase. Spherically
symmetric radiative transfer calculations of uniform-outflow dust shell models
produce brightness distributions and spectra which partially explain the data,
however limitations to this approximation are noted. Evidence for significant
deviation from circular symmetry was found in the mid-infrared and more
tentatively at 3.08 microns in the near-infrared, however no clear detection of
binarity or of non-LPV elements in the symbiotic system is reported.Comment: Accepted to Astrophysical Journal. To appear in volume 534. 14 pages;
3 postscript figure
Star Formation in M51 Triggered by Galaxy Interaction
We have mapped the inner 360'' regions of M51 in the 158micron [CII] line at
55'' spatial resolution using the Far-infrared Imaging Fabry-Perot
Interferometer (FIFI) on the Kuiper Airborne Observatory (KAO). The emission is
peaked at the nucleus, but is detectable over the entire region mapped, which
covers much of the optical disk of the galaxy. There are also two strong
secondary peaks at ~43% to 70% of the nuclear value located roughly 120'' to
the north-east, and south-west of the nucleus. These secondary peaks are at the
same distance from the nucleus as the corotation radius of the density wave
pattern. The density wave also terminates at this location, and the outlying
spiral structure is attributed to material clumping due to the interaction
between M51 and NGC5195. This orbit crowding results in cloud-cloud collisions,
stimulating star formation, that we see as enhanced [CII] line emission. The
[CII] emission at the peaks originates mainly from photodissociation regions
(PDRs) formed on the surfaces of molecular clouds that are exposed to OB
starlight, so that these [CII] peaks trace star formation peaks in M51. The
total mass of [CII] emitting photodissociated gas is ~2.6x10^{8} M_{sun}, or
about 2% of the molecular gas as estimated from its CO(1-0) line emission. At
the peak [CII] positions, the PDR gas mass to total gas mass fraction is
somewhat higher, 3-17%, and at the secondary peaks the mass fraction of the
[CII] emitting photodissociated gas can be as high as 72% of the molecular
mass.... (continued)Comment: 14 pages, 6 figures, Accepted in ApJ (for higher resolution figures
contact the author
Neuroblast mitosis in dissociated culture: regulation and relationship to differentiation.
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