312 research outputs found
High-spectral resolution observations of the 3.29 micron emission feature: Comparison to QCC and PAHs
Two of the most promising explanations for the origin of the interstellar emission features observed at 3.29, 3.4, 6.2, 7.7, 8.6, and 11.3 microns are: quenched carbonaceous composite (QCC) and polycyclic aromatic hydrocarbons (PAHs). High resolution spectra are given of the 3.29 micron emission feature which were taken with the Cooled Grating Array Spectrometer at the NASA Infrared Telescope Facility and previously published. These spectra show that the peak wavelength of the 3.29 micron feature is located at 3.295 + or - 0.005 micron and that it is coincident with the peak absorbance of QCC. The peak wavelength of the 3.29 micron feature appears to be the same in all of the sources observed thus far. However, the width of the feature in HD 44179 and Elias 1 is only 0.023 micron, which is smaller than the 0.043 micron width in NGC 7027, IRAS 21282+5050, the Orion nebula, and BD+30 deg 3639. Spectra of NGC 7027, QCC, and PAHs is shown. QCC matches the 3.29 micron interstellar emission feature very closely in the wavelength of the peak, and it produces a single feature. On the other hand, PAHs rarely match the peak of the interstellar emission feature, and characteristically produce multiple features
New “missing link” genus of the colonial volvocine green algae gives insights into the evolution of oogamy
Data of Project on Atmospheric Circulation and Material Cycle in the Antarctic, Part 3. Backscattering Properties of Tropospheric Clouds and Aerosols Observed by a Lidar at Dome Fuji Station in 1997
Non-local mean field effect on nuclei near Z=64 sub-shell
Evolutions of single-particle energies and Z=64 sub-shell along the isotonic
chain of N=82 are investigated in the density dependent relativistic
Hartree-Fock (DDRHF) theory in comparison with other commonly used mean field
models such as Skyrme HF, Gogny HFB and density dependent relativistic Hartree
model (DDRMF). The pairing is treated in the BCS scheme, except for Gogny HFB.
It is pointed out that DDRHF reproduces well characteristic features of
experimental -dependence of both spin orbital and pseudo-spin orbital
splittings around the sub-shell closure Z=64. Non-local exchange terms of the
isoscalar and couplings play dominant roles in the
enhancements of the spin-orbit splitting of proton 2d states, which is the key
ingredient to give the Z=64 sub-shell closure properly. On the other hand, the
and tensor contributions for the spin-orbit splitting cancel each
other and the net effect becomes rather small. The enhancement of the sub-shell
gaps towards Z=64 is studied by the DDRHF, for which the local terms of the
scalar and vector meson couplings are found to be important.Comment: 4 figure
Critical temperature and correlation length of an elastic interaction model for spin-crossover materials
It has previously been pointed out that the coexistence of infinite-range and
short-range interactions causes a system to have a phase transition of the
mean-field universality class, in which the cluster size is finite even at the
critical point. In the present paper, we study this property in a model of
bistable molecules, whose size changes depending on the bistable states. The
molecules can move in space, interacting via an elastic interaction. It is
known that due to the different sizes, an effective long-range interaction
between the spins appears, and thus this model has a mean-field type of phase
transition. It is found that the scaling properties of the shift of the
critical temperature from the pure short-range limit in the model with
infinite-range and short-range interactions hold also in the present model,
regarding the ratio of the size of the two states as a control parameter for
the strength of the long-range interaction. By studying the structure factor,
it is shown that the dependence of the cluster size at the critical temperature
also shows the same scaling properties as a previously studied model with both
infinite-range and short-range interactions. We therefore conclude that these
scaling relations hold universally in hybrid models with both short-range and
weak long-range interactions
Microscopic description of nuclei in the middle of the pf-shell by a shell model calculation with G-matrix interaction
Energy levels and electromagnetic properties of with nuclides
are studied in terms of a large-scale shell model calculation, which contains
no newly adjusted parameters. The Kuo-Brown -matrix interaction is shown to
reproduce energy levels of 205 low-lying states of these nuclei. We evaluate
effective charges by incorporating the core-polarization effects caused by the
coupling to GQR's. We then compute E2 moments and transition probabilities. The
M1 moments and transition rates are calculated by quoting the effective
-factors of Towner, which are obtained by taking into account the
meson-exchange and the core-polarization mechanisms. By this microscopic
calculation most of the E2 properties and the magnetic moments are reproduced.
Although there are agreements and disagreements in the M1 transition rates, the
general tendency is reproduced. The and excitation from the
ground state to some low-lying states is also discussed.Comment: 63 pages (LaTeX, to be published in Nucl. Phys. A
Patterns of population structure and complex haplotype sharing among field isolates of the green alga Chlamydomonas reinhardtii
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