101,355 research outputs found
Crystalline sulfur dioxide: Crystal field splittings, absolute band intensities and complex refractive indices derived from infrared spectra
The infrared absorption spectra of thin crystalline films of sulfur dioxide at 90 K are reported in the 2700 to 450/cm region. The observed multiplicity of the spectral features in the regions of fundamentals is attributed to factor group splittings of the modes in a biaxial crystal lattice and the naturally present minor S-34, S-36, and O-18 isotopic species. Complex refractive indices determined by an iterative Kramers-Kronig analysis of the extinction data, and absolute band strengths derived from them, are also reported in this region
Correction function in the Lidar equation and the solution techniques for CO2 Lidar date reduction
For lidar systems with long laser pulses the unusual behavior of the near-range signals causes serious difficulties and large errors in reduction. The commonly used lidar equation is no longer applicable since the convolution of the laser pulse with the atmospheric parameter distributions should be taken into account. It is important to give more insight into this problem and find the solution techniques. Starting from the original equation, a general form is suggested for the single scattering lidar equation where a correction function Cr is introduced. The correction Function Cr(R) derived from the original equation indicates the departure from the normal lidar equation. Examples of Cr(R) for a coaxial CO2 lidar system are presented. The Differential Absorption Lidar (DIAL) errors caused by the differences of Cr(R) for H2O measurements are plotted against height
On several families of elliptic curves with arbitrary large Selmer groups
In this paper, we calculate the Selmer groups
S^{(\phi)} (E / \Q) and S^{(\hat{\varphi})} (E^{\prime} / \Q) of elliptic
curves via descent theory
(see [S, Chapter X]), in particular, we obtain that the Selmer groups of
several families of such elliptic curves can be arbitrary large.Comment: 22 page
Anomalous Hall effect in non-collinear antiferromagnetic antiperovskite MnNiCuN
We report the anomalous Hall effect (AHE) in antiperovskite MnNiN with
substantial doping of Cu on the Ni site (i.e. MnNiCuN),
which stabilizes a noncollinear antiferromagnetic (AFM) order compatible with
the AHE. Observed on both sintered polycrystalline pieces and single
crystalline films, the AHE does not scale with the net magnetization, contrary
to the conventional ferromagnetic case. The existence of the AHE is explained
through symmetry analysis based on the AFM order in Cu doped
MnNiN. DFT calculations of the intrinsic contribution to the AHE reveal
the non-vanishing Berry curvature in momentum space due to the noncollinear
magnetic order. Combined with other attractive properties, antiperovskite
MnAN system offers great potential in AFM spintronics.Comment: Supplemental Materials not include
Hierarchy of fractional Chern insulators and competing compressible states
We study the phase diagram of interacting electrons in a dispersionless Chern
band as a function of their filling. We find hierarchy multiplets of
incompressible states at fillings \nu=1/3, 2/5, 3/7, 4/9, 5/9, 4/7, 3/5 as well
as \nu=1/5,2/7. These are accounted for by an analogy to Haldane
pseudopotentials extracted from an analysis of the two-particle problem.
Important distinctions to standard fractional quantum Hall physics are
striking: absent particle-hole symmetry in a single band, an
interaction-induced single-hole dispersion appears, which perturbs and
eventually destabilizes incompressible states as \nu increases. For this reason
the nature of the state at \nu=2/3 is hard to pin down, while \nu=5/7,4/5 do
not seem to be incompressible in our system.Comment: 5 pages with 4 figures, plus 6 pages and 8 figures of supplementary
materia
Are dwarf spheroidal galaxies dark matter dominated or remnants of disrupted larger satellite galaxies? -- A possible test
The failure of standard cosmolocical models in accounting for the statistics
of dwarf satellites and the rotation curve of gas-rich dwarf galaxies in detail
has led us to examine whether earlier non-equilibrium models of dwarf
spheroidal satellites without any dark matter should be reconsidered in more
detail. Such models can explain the high dispersion of the dwarf spheroids by
the projection of disrupted tidal debris. We show in the case of Milky Way
satellites, that these models predict a significant spread in the apparent
magnitude of horizontal branch stars which is correlated with sky position and
velocity. In particular, the models produce a strong correlation of radial
velocity with the long axis of the dwarf. Current data do not set strong enough
constraints on the models, but we suggest that photometric and spectroscopic
surveys of extra-tidal stars of nearby dwarf spheroids in the Milky Way and
Andromeda can falsify these models without dark matter.Comment: 7 pages, 5 figures, accepted for publication in Ap
Organoaluminium complexes of ortho-, meta-, para-anisidines: synthesis, structural studies and ROP of ε-caprolactone (and rac-lactide)
Reaction of Me₃Al (two equivalents) with ortho-, meta- or para-anisidine, (OMe)(NH₂)C₆H₄, affords the complexes {[1,2-(OMe),NC₆H₄(μ-Me₂Al)](μ-Me₂Al)}₂ (1), [1,3-(Me₃AlOMe),NHC₆H₄(μ-Me₂Al)]2 (2) or [1,4-(Me₃AlOMe),NHC₆H₄(μ-Me₂Al)]₂ (3), respectively. The molecular structures of 1–3 have been determined and all three complexes were found to be highly active for the ring opening polymerization (ROP) of ε-caprolactone. 1 was found highly active either with or without benzyl alcohol present; at various temperatures, the activity order 1 > 2 ≈ 3 was observed. For the ROP of rac-lactide results for 1–3 were poor
- …