90 research outputs found
Maser action in methanol transitions
We report the detection with the ATCA of 6.7 GHz methanol emission towards
OMC-1. The source has a size between 40'' and 90'', is located to the
south-east of Ori-KL and may coincide in position with the 25 GHz masers. The
source may be an example of an interesting case recently predicted in theory
where the transitions of traditionally different methanol maser classes show
maser activity simultaneously. In addition, results of recent search for
methanol masers from the 25 and 104.3 GHz transitions are reported.Comment: To appear in the Proceedings of the 2004 European Workshop: "Dense
Molecular Gas around Protostars and in Galactic Nuclei", Eds. Y.Hagiwara,
W.A.Baan, H.J. van Langevelde, 2004, a special issue of ApSS, Kluwer; author
list has been corrected, text is unchange
Computational Analysis of the Shutdown of One MCP of VVER-1000 During Operation of the Reactor Facility at Nominal Power
The article considers results of the computational analysis of process with a disturbance in the operation of VVER-1000 reactor facility, caused by the de-energizing of a single Main Circulation Pump (MCP-195).Calculations of de-energizing of the MCP were made with the CORSAR/GP software package developed by Federal State Unitary Enterprise "Alexandrov RESE". This software package is a contour code which allows making calculations of emergency situations taking into account the operation of various systems, including safety systems. CORSAR/GP is certified and verified for facilities with water-cooled reactors including VVER-1000.Developed nodalization scheme (computational scheme) of the first circuit of VVER-1000 allows adding or excluding the operation of protective safety systems and can also be used for a computational analysis of other disturbances of normal operation.To perform the calculations parameters of the core were chosen to ensure conservative results for the parameters determining the current state of the reactor facility (fuel temperature, boiling point, etc.).The computational analysis showed that in case of de-energizing of a single MCP when the reactor is operated at nominal power criteria describing the safety of the facility are fulfilled, protective automatic actions of safety systems transfer the reactor facility to a controlled safe state
Model of the W3(OH) environment based on data for both maser and 'quasi-thermal' methanol lines
In studies of the environment of massive young stellar objects, recent
progress in both observations and theory allows a unified treatment of data for
maser and 'quasi-thermal' lines. Interferometric maser images provide
information on the distribution and kinematics of masing gas on small spatial
scales. Observations of multiple masing transitions provide constraints on the
physical parameters.
Interferometric data on 'quasi-thermal' molecular lines permits an
investigation of the overall distribution and kinematics of the molecular gas
in the vicinity of young stellar objects, including those which are deeply
embedded. Using multiple transitions of different molecules, one can obtain
good constraints on the physical and chemical parameters.
Combining these data enables the construction of unified models, which take
into account spatial scales differing by orders of magnitude.
Here we present such a combined analysis of the environment around the
ultracompact HII region in W3(OH). This includes the structure of the methanol
masing region, physical structure of the near vicinity of W3(OH), detection of
new masers in the large-scale shock front and embedded sources in the vicinity
of the TW young stellar object.Comment: To appear in the Proceedings of the 2004 European Workshop: "Dense
Molecular Gas around Protostars and in Galactic Nuclei", Eds. Y.Hagiwara,
W.A.Baan, H.J. van Langevelde, 2004, a special issue of ApSS, Kluwe
Second order semiclassics with self-generated magnetic fields
We consider the semiclassical asymptotics of the sum of negative eigenvalues
of the three-dimensional Pauli operator with an external potential and a
self-generated magnetic field . We also add the field energy and we minimize over all magnetic fields. The parameter
effectively determines the strength of the field. We consider the weak field
regime with , where is the semiclassical
parameter. For smooth potentials we prove that the semiclassical asymptotics of
the total energy is given by the non-magnetic Weyl term to leading order with
an error bound that is smaller by a factor h^{1+\e}, i.e. the subleading term
vanishes. However, for potentials with a Coulomb singularity the subleading
term does not vanish due to the non-semiclassical effect of the singularity.
Combined with a multiscale technique, this refined estimate is used in the
companion paper \cite{EFS3} to prove the second order Scott correction to the
ground state energy of large atoms and molecules.Comment: Small typos corrected on Sep 24, 201
Scott correction for large atoms and molecules in a self-generated magnetic field
We consider a large neutral molecule with total nuclear charge in
non-relativistic quantum mechanics with a self-generated classical
electromagnetic field. To ensure stability, we assume that Z\al^2\le \kappa_0
for a sufficiently small , where \al denotes the fine structure
constant. We show that, in the simultaneous limit , \al\to 0 such
that \kappa =Z\al^2 is fixed, the ground state energy of the system is given
by a two term expansion . The leading
term is given by the non-magnetic Thomas-Fermi theory. Our result shows that
the magnetic field affects only the second (so-called Scott) term in the
expansion
Cantor and band spectra for periodic quantum graphs with magnetic fields
We provide an exhaustive spectral analysis of the two-dimensional periodic
square graph lattice with a magnetic field. We show that the spectrum consists
of the Dirichlet eigenvalues of the edges and of the preimage of the spectrum
of a certain discrete operator under the discriminant (Lyapunov function) of a
suitable Kronig-Penney Hamiltonian. In particular, between any two Dirichlet
eigenvalues the spectrum is a Cantor set for an irrational flux, and is
absolutely continuous and has a band structure for a rational flux. The
Dirichlet eigenvalues can be isolated or embedded, subject to the choice of
parameters. Conditions for both possibilities are given. We show that
generically there are infinitely many gaps in the spectrum, and the
Bethe-Sommerfeld conjecture fails in this case.Comment: Misprints correcte
First record of Rhabdoceras suessi (Ammonoidea, Late Triassic) from the Transylvanian Triassic Series of the Eastern Carpathians (Romania) and a review of its biochronology, paleobiogeography and paleoecology
Abstract
The occurrence of the heteromorphic ammonoid Rhabdoceras suessi Hauer, 1860, is recorded for the first time in the Upper Triassic limestone of the Timon-Ciungi olistolith in the Rarău Syncline, Eastern Carpathians. A single specimen of Rhabdoceras suessi co-occurs with Monotis (Monotis) salinaria that constrains its occurrence here to the Upper Norian (Sevatian 1). It is the only known heteromorphic ammonoid in the Upper Triassic of the Romanian Carpathians. Rhabdoceras suessi is a cosmopolitan species widely recorded in low and mid-paleolatitude faunas. It ranges from the Late Norian to the Rhaetian and is suitable for high-resolution worldwide correlations only when it co-occurs with shorter-ranging choristoceratids, monotid bivalves, or the hydrozoan Heterastridium. Formerly considered as the index fossil for the Upper Norian (Sevatian) Suessi Zone, by the latest 1970s this species lost its key biochronologic status among Late Triassic ammonoids, and it generated a controversy in the 1980s concerning the status of the Rhaetian stage. New stratigraphic data from North America and Europe in the subsequent decades resulted in a revised ammonoid biostratigraphy for the uppermost Triassic, the Rhaetian being reinstalled as the topmost stage in the current standard timescale of the Triassic. The geographic distribution of Rhabdoceras is compiled from published worldwide records, and its paleobiogeography and paleoecology are discussed
MULTICOMPONENT SOLUTION FOR LOCAL ANAESTHESIA IN OPERATIONS ON EXTREMITIES
The analysis of the results of local anaesthesia (LA) in 89 patients aged 18 to 68 years with trauma and diseases of extremities has been carried out. The efficiency of perineural injected multicomponent solution of clonidine added to conventional mixture oflidocaine and phentanyl has been assessed. The multicomponent method has significantly prolonged the duration of local anaesthesia of 1% lidocaine solution providing reliable anaesthesia of plexus and peripheral nerves alongside the sufficient regional myoplegia and prolonged postoperative anesthetization. When there is no need of deep myoplegia Hallows to lower the concentration of lidocaine solution twofold, maintaining its efficiency, and to realize local anaesthesia of patients with high risk
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