762 research outputs found
The statistics of the photometric accuracy based on MASS data and the evaluation of high-altitude wind
The effect of stellar scintillation on the accuracy of photometric
measurements is analyzed. We obtain a convenient form of estimaton of this
effect in the long exposure regime, when the turbulence shift produced by the
wind is much larger than the aperture of the telescope. A simple method is
proposed to determine index introduced by perture of the Kenyon et al.
(2006), directly from the measurements with the Multi Aperture Scintillation
Sensor (MASS) without information on vertical profile of the wind. The
statistics resulting from our campaign of 2005 -- 2007 at Maidanak
observatory is presented. It is shown that these data can be used to estimate
high-altitude winds at pressure level 70 -- 100 mbar. Comparison with the wind
speed retrieved from the NCEP/NCAR global models shows a good agreement. Some
prospects for retrieval of the wind speed profile from the MASS measurements
are outlined.Comment: 11 pages, 9 figures, accepted for publication in Astronomy Letter
First results of site testing program at Mt. Shatdzhatmaz in 2007 - 2009
We present the first results of the site testing performed at
Mt.~Shatdzhatmaz at Northern Caucasus, where the new Sternberg astronomical
institute 2.5-m telescope will be installed. An automatic site monitor
instrumentation and functionality are described together with the methods of
measurement of the basic astroclimate and weather parameters. The clear night
sky time derived on the basis of 2006 -- 2009 data amounts to 1340 hours per
year. Principle attention is given to the measurement of the optical turbulence
altitude distribution which is the most important characteristic affecting
optical telescopes performance. For the period from November 2007 to October
2009 more than 85\,000 turbulence profiles were collected using the combined
MASS/DIMM instrument. The statistical properties of turbulent atmosphere above
the summit are derived and the median values for seeing ~arcsec
and free-atmosphere seeing ~arcsec are determined.
Together with the estimations of isoplanatic angle ~arcsec and
time constant \tau_0 = 2.58 \mbox{ ms}, these are the first representative
results obtained for Russian sites which are necessary for development of
modern astronomical observation techniques like adaptive optics.Comment: Accepted for publication in MNRAS, 17 pages, 15 figure
On the focused beam parameters of an electron gun with a plasma emitter
The report presents the measurement results of the focused beam brightness in the electron gun with plasma emitter. The beam brightness was approximately 1010 A·m-2·sr-1 under the beam power up to 4 kW and an electron energy of 60 keV at the focal distance of 0.5 m. Qualitative assessment of the beam parameters was performed by welding test pieces. The results describing the possibility in principle of using the guns with a plasma emitter in nonvacuum technological devices are presented
Comprehensive evaluation of combined pharmacotherapy of cardiac pathology considering exogenous and pharmacogenetic factors
The study assessed changes in hemodynamic and biochemical parameters, vascular age and 5-year cardiovascular risk on the background of complex pharmacotherapy in patients with stable angina I-III functional class (FC), hypertension of I-III degree, chronic heart failure (CHF) II-III FC taking into account the influence of exogenous and pharmacogenetic factor
Combined MASS-DIMM instrument for atmospheric turbulence studies
Several site-testing programs and observatories currently use combined
MASS-DIMM instruments for monitoring parameters of optical turbulence. The
instrument is described here. After a short recall of the measured quantities
and operational principles, the optics and electronics of MASS-DIMM,
interfacing to telescopes and detectors, and operation are covered in some
detail. Particular attention is given to the correct measurement and control of
instrumental parameters to ensure valid and well-calibrated data, to the data
quality and filtering. Examples of MASS-DIMM data are given, followed by the
list of present and future applications.Comment: Accepted by MNRAS, 11 pages, 8 figure
THE DEVELOPMENT OF STUDENTS APPLIED MATHEMATICAL THINKING IN TEACHING INVERSE AND ILL-POSED PROBLEMS
In the article the author draws the reader’s attention to the fact that, while mastering the process of learning the theory and methodology of inverse and ill-posed problems, students not only form the fundamental knowledge in the field of inverse and ill-posed problems, applied and computational mathematics, mathematical modeling of processes and phenomena, but also develop one of the most important component of mathematical ability creative and applied mathematical thinking.It is emphasized that the search for solutions to inverse and ill-posed problems, students acquire profound knowledge in such scientific fields as seismology, gravimetry, magnetometry, Geophysics, astrophysics, imaging, electrodynamics, atmospheric optics, quantum scattering theory and other scientific fields. When teaching inverse and ill-posed problems, students also learn the mathematical methods, which are not included in the content of traditional mathematics applied and computational mathematics, and can only be purchased in the teaching of special courses. Among them, spectral analysis, the method of Volterra operator equations, Sobolev method, method of scales of Banach spaces of analytic functions, the method of integral geometry, the method of tensor analysis, methods of computational mathematics and other mathematical methods
DEVELOPMENT OF SCIENTIFIC AND INFORMATIVE POTENTIAL OF STUDENTS IN THE TEACHING OF THE INVERSE PROBLEMS FOR DIFFERENTIAL EQUATIONS
In article attention that when training in the inverse problems for differential equations at students scientific and cognitive potential develops is paid. Students realize that mathematical models of the inverse problems for differential equations find the application in economy, the industries, ecology, sociology, biology, chemistry, mathematician, physics, in researches of the processes and the phenomena occurring in water and earth’s environment, air and space.Attention of the reader that in training activity to the inverse problems for differential equations at students the scientific outlook, logical, algorithmic, information thinking, creative activity, independence and ingenuity develop is focused. Students acquire skills to apply knowledge of many physical and mathematical disciplines, to carry out the analysis of the received decision of the reverse task and to formulate logical outputs of application-oriented character. Solving the inverse problems for differential equations, students acquire new knowledge in the field of applied and calculus mathematics, informatics, natural sciences and other knowledge
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