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  Subjects -> ENGINEERING (Total: 2287 journals)
    - CHEMICAL ENGINEERING (192 journals)
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ENGINEERING (1206 journals)                  1 2 3 4 5 6 7 | Last

Showing 1 - 200 of 1205 Journals sorted alphabetically
3 Biotech     Open Access   (Followers: 7)
3D Research     Hybrid Journal   (Followers: 19)
AAPG Bulletin     Hybrid Journal   (Followers: 6)
AASRI Procedia     Open Access   (Followers: 15)
Abstract and Applied Analysis     Open Access   (Followers: 3)
Aceh International Journal of Science and Technology     Open Access   (Followers: 2)
ACS Nano     Full-text available via subscription   (Followers: 234)
Acta Geotechnica     Hybrid Journal   (Followers: 7)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 5)
Acta Polytechnica : Journal of Advanced Engineering     Open Access   (Followers: 2)
Acta Scientiarum. Technology     Open Access   (Followers: 3)
Acta Universitatis Cibiniensis. Technical Series     Open Access  
Active and Passive Electronic Components     Open Access   (Followers: 7)
Adaptive Behavior     Hybrid Journal   (Followers: 11)
Adıyaman Üniversitesi Mühendislik Bilimleri Dergisi     Open Access  
Adsorption     Hybrid Journal   (Followers: 4)
Advanced Engineering Forum     Full-text available via subscription   (Followers: 6)
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Advanced Science Letters     Full-text available via subscription   (Followers: 7)
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Advances in Engineering Software     Hybrid Journal   (Followers: 25)
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Advances in Physics Theories and Applications     Open Access   (Followers: 12)
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Advances in Science and Research (ASR)     Open Access   (Followers: 6)
Aerobiologia     Hybrid Journal   (Followers: 1)
African Journal of Science, Technology, Innovation and Development     Hybrid Journal   (Followers: 4)
AIChE Journal     Hybrid Journal   (Followers: 30)
Ain Shams Engineering Journal     Open Access   (Followers: 5)
Akademik Platform Mühendislik ve Fen Bilimleri Dergisi     Open Access  
Alexandria Engineering Journal     Open Access   (Followers: 1)
AMB Express     Open Access   (Followers: 1)
American Journal of Applied Sciences     Open Access   (Followers: 28)
American Journal of Engineering and Applied Sciences     Open Access   (Followers: 11)
American Journal of Engineering Education     Open Access   (Followers: 9)
American Journal of Environmental Engineering     Open Access   (Followers: 16)
American Journal of Industrial and Business Management     Open Access   (Followers: 23)
Analele Universitatii Ovidius Constanta - Seria Chimie     Open Access  
Annals of Combinatorics     Hybrid Journal   (Followers: 3)
Annals of Pure and Applied Logic     Open Access   (Followers: 2)
Annals of Regional Science     Hybrid Journal   (Followers: 7)
Annals of Science     Hybrid Journal   (Followers: 7)
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 2)
Applicable Analysis: An International Journal     Hybrid Journal   (Followers: 1)
Applied Catalysis A: General     Hybrid Journal   (Followers: 6)
Applied Catalysis B: Environmental     Hybrid Journal   (Followers: 15)
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Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 4)
Arabian Journal for Science and Engineering     Hybrid Journal   (Followers: 5)
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Archives of Thermodynamics     Open Access   (Followers: 7)
Arkiv för Matematik     Hybrid Journal   (Followers: 1)
ASEE Prism     Full-text available via subscription   (Followers: 3)
Asian Engineering Review     Open Access  
Asian Journal of Applied Science and Engineering     Open Access   (Followers: 1)
Asian Journal of Applied Sciences     Open Access   (Followers: 2)
Asian Journal of Biotechnology     Open Access   (Followers: 8)
Asian Journal of Control     Hybrid Journal  
Asian Journal of Current Engineering & Maths     Open Access  
Asian Journal of Technology Innovation     Hybrid Journal   (Followers: 8)
Assembly Automation     Hybrid Journal   (Followers: 2)
at - Automatisierungstechnik     Hybrid Journal   (Followers: 1)
ATZagenda     Hybrid Journal  
ATZextra worldwide     Hybrid Journal  
Australasian Physical & Engineering Sciences in Medicine     Hybrid Journal   (Followers: 1)
Australian Journal of Multi-Disciplinary Engineering     Full-text available via subscription   (Followers: 2)
Autonomous Mental Development, IEEE Transactions on     Hybrid Journal   (Followers: 8)
Avances en Ciencias e Ingeniería     Open Access  
Balkan Region Conference on Engineering and Business Education     Open Access   (Followers: 1)
Bangladesh Journal of Scientific and Industrial Research     Open Access  
Basin Research     Hybrid Journal   (Followers: 5)
Batteries     Open Access   (Followers: 4)
Bautechnik     Hybrid Journal   (Followers: 1)
Bell Labs Technical Journal     Hybrid Journal   (Followers: 23)
Beni-Suef University Journal of Basic and Applied Sciences     Open Access   (Followers: 4)
BER : Manufacturing Survey : Full Survey     Full-text available via subscription   (Followers: 2)
BER : Motor Trade Survey     Full-text available via subscription   (Followers: 1)
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BER : Survey of Business Conditions in Manufacturing : An Executive Summary     Full-text available via subscription   (Followers: 3)
BER : Survey of Business Conditions in Retail : An Executive Summary     Full-text available via subscription   (Followers: 3)
Bharatiya Vaigyanik evam Audyogik Anusandhan Patrika (BVAAP)     Open Access   (Followers: 1)
Biofuels Engineering     Open Access  
Biointerphases     Open Access   (Followers: 1)
Biomaterials Science     Full-text available via subscription   (Followers: 10)
Biomedical Engineering     Hybrid Journal   (Followers: 16)
Biomedical Engineering and Computational Biology     Open Access   (Followers: 13)
Biomedical Engineering Letters     Hybrid Journal   (Followers: 5)
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 17)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 31)
Biomedical Engineering: Applications, Basis and Communications     Hybrid Journal   (Followers: 5)
Biomedical Microdevices     Hybrid Journal   (Followers: 9)
Biomedical Science and Engineering     Open Access   (Followers: 4)
Biomedizinische Technik - Biomedical Engineering     Hybrid Journal  
Biomicrofluidics     Open Access   (Followers: 4)
BioNanoMaterials     Hybrid Journal   (Followers: 2)
Biotechnology Progress     Hybrid Journal   (Followers: 39)
Boletin Cientifico Tecnico INIMET     Open Access  
Botswana Journal of Technology     Full-text available via subscription  
Boundary Value Problems     Open Access   (Followers: 1)
Brazilian Journal of Science and Technology     Open Access   (Followers: 2)
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 10)
Bulletin of Canadian Petroleum Geology     Full-text available via subscription   (Followers: 14)
Bulletin of Engineering Geology and the Environment     Hybrid Journal   (Followers: 3)
Bulletin of the Crimean Astrophysical Observatory     Hybrid Journal  
Cahiers, Droit, Sciences et Technologies     Open Access  
Calphad     Hybrid Journal  
Canadian Geotechnical Journal     Hybrid Journal   (Followers: 14)
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 41)
Case Studies in Engineering Failure Analysis     Open Access   (Followers: 8)
Case Studies in Thermal Engineering     Open Access   (Followers: 3)
Catalysis Communications     Hybrid Journal   (Followers: 6)
Catalysis Letters     Hybrid Journal   (Followers: 2)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 8)
Catalysis Science and Technology     Free   (Followers: 6)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysis Today     Hybrid Journal   (Followers: 8)
CEAS Space Journal     Hybrid Journal  
Cellular and Molecular Neurobiology     Hybrid Journal   (Followers: 3)
Central European Journal of Engineering     Hybrid Journal   (Followers: 1)
CFD Letters     Open Access   (Followers: 6)
Chaos : An Interdisciplinary Journal of Nonlinear Science     Hybrid Journal   (Followers: 2)
Chaos, Solitons & Fractals     Hybrid Journal   (Followers: 3)
Chinese Journal of Catalysis     Full-text available via subscription   (Followers: 2)
Chinese Journal of Engineering     Open Access   (Followers: 2)
Chinese Science Bulletin     Open Access   (Followers: 1)
Ciencia e Ingenieria Neogranadina     Open Access  
Ciencia en su PC     Open Access   (Followers: 1)
Ciencias Holguin     Open Access   (Followers: 1)
CienciaUAT     Open Access  
Cientifica     Open Access  
CIRP Annals - Manufacturing Technology     Full-text available via subscription   (Followers: 11)
CIRP Journal of Manufacturing Science and Technology     Full-text available via subscription   (Followers: 14)
City, Culture and Society     Hybrid Journal   (Followers: 21)
Clay Minerals     Full-text available via subscription   (Followers: 10)
Clean Air Journal     Full-text available via subscription   (Followers: 2)
Coal Science and Technology     Full-text available via subscription   (Followers: 3)
Coastal Engineering     Hybrid Journal   (Followers: 11)
Coastal Engineering Journal     Hybrid Journal   (Followers: 5)
Coatings     Open Access   (Followers: 3)
Cogent Engineering     Open Access   (Followers: 2)
Cognitive Computation     Hybrid Journal   (Followers: 4)
Color Research & Application     Hybrid Journal   (Followers: 1)
COMBINATORICA     Hybrid Journal  
Combustion Theory and Modelling     Hybrid Journal   (Followers: 13)
Combustion, Explosion, and Shock Waves     Hybrid Journal   (Followers: 13)
Communications Engineer     Hybrid Journal   (Followers: 1)
Communications in Numerical Methods in Engineering     Hybrid Journal   (Followers: 2)
Components, Packaging and Manufacturing Technology, IEEE Transactions on     Hybrid Journal   (Followers: 26)
Composite Interfaces     Hybrid Journal   (Followers: 6)
Composite Structures     Hybrid Journal   (Followers: 258)
Composites Part A : Applied Science and Manufacturing     Hybrid Journal   (Followers: 180)
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Control Theory and Informatics     Open Access   (Followers: 8)
Corrosion Science     Hybrid Journal   (Followers: 25)
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CTheory     Open Access  
Current Applied Physics     Full-text available via subscription   (Followers: 4)
Current Science     Open Access   (Followers: 58)

        1 2 3 4 5 6 7 | Last

Journal Cover Bulletin of the Crimean Astrophysical Observatory
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   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1934-7863 - ISSN (Online) 0190-2717
   Published by Springer-Verlag Homepage  [2353 journals]
  • The photospheric spectrum of the pre-FUor V1331 CYG: Is it a star or a
           disk?
    • Authors: P. P. Petrov; E. V. Babina
      Pages: 1 - 8
      Abstract: Abstract The T Tauri variable V1331 Cyg is characterized by an intensive emission spectrum, by signatures of a high rate of mass loss, and also by presence of a circular reflection nebula. According to these characteristics, the star can be considered as a possible pre-FUor star. Up to the present the photospheric spectrum of the star has not been recorded. In this work we analyze the high-resolution spectra of V1331 Cyg that were obtained by G.H. Herbig with the HIRES spectrograph at the Keck-1 telescope in 2004 and 2007. For the first time the numerous photospheric lines of the star have been detected and the spectral class has been estimated, viz., G7-K0 IV. It is revealed that the projection of the rotation velocity is lower than the width of instrumental profile (vsini < 6 km/s); this means that the angle between the stellar axis of rotation and the line of sight is small. The radial velocity of the star derived from the photospheric lines is RV = −15.0 ± 0.3 km/s. The difference in radial velocities for 2004 and 2007 is lower than the measurement error. The photospheric spectrum is veiled considerably, but the amount of veiling is not the same in different lines. This depends on the line strength in the template spectrum of the G7 IV star: in the weakest lines (EW = 5–10 mÅ in the template spectrum) VF ≈ 1 and it increases up to 4–5 in stronger lines. The Hα and Hβ lines demonstrate classical P Cyg profiles, which testifies to an intensive wind with a maximal velocity of about 400 km/s. In addition, the emission lines of Fe II, Mg I and K I and of several other elements are accompanied by a narrow blue-shifted absorption at −150...−250 km/s. The emission spectrum of V1331 Cyg is rich in the narrow (FWHM = 30–50 km/s) lines of neutral and ionized metals showing the excitation temperature T exc = 3800 ± 300 K. The stellar mass M* ≈ 2.8M ⊙ and radius R* ≈ 5R ⊙ are estimated.
      PubDate: 2014-06-01
      DOI: 10.3103/s0190271714010203
      Issue No: Vol. 110, No. 1 (2014)
       
  • Superheavy elements in the atmospheres of magnetic stars
    • Authors: L. S. Lyubimkov
      Pages: 9 - 16
      Abstract: Abstract The studies of the abundances of superheavy chemical elements in magnetic stars conducted at the Crimean Astrophysical Observatory were facilitated by the launch of the Astron space station in 1983. This spacecraft observed the ultraviolet spectra of such stars. The present brief review is focused on the abundances of superheavy elements (Pt, Au, Hg, Tl, Pb, Bi, Th, and U) in the atmospheres of magnetic Ap and HgMn stars. These results were obtained basing on the visible and ultraviolet spectra of stars. The data accumulated over more than 30 years show that these stars are characterized by significant overabundances (up to 6–7 dex) of such elements. The following important fact is noted: the superheavy element anomalies follow the trend in the anomalies that are characteristic of less heavy elements. Therefore, it may be assumed that all these anomalies (including the significant overabundances of superheavy elements) share a common explanation. Certain unresolved problems are discussed briefly.
      PubDate: 2014-06-01
      DOI: 10.3103/s0190271714010173
      Issue No: Vol. 110, No. 1 (2014)
       
  • High-precision measurements of global stellar magnetic fields
    • Authors: S. I. Plachinda
      Pages: 17 - 22
      Abstract: Abstract This paper presents a brief history of the development of devices and techniques for high-precision measurements of stellar magnetic fields. Two main approaches for the processing of spectral-polarimetric observations are described: the method of least-squares deconvolution (LSD), which is used to find a mean-weighted average of the normalized polarization profile using a set of spectral lines, and a method in which each individual spectral line is used to determine the magnetic field, viz., the single line method (SL). The advantages and disadvantages of the LSD and SL methods are discussed.
      PubDate: 2014-06-01
      DOI: 10.3103/s0190271714010215
      Issue No: Vol. 110, No. 1 (2014)
       
  • Secular variations of the photometric parameters of Mira Ceti variables
           and semiregular variables
    • Authors: V. I. Marsakova
      Pages: 23 - 29
      Abstract: Abstract The photometric properties of long-period variable stars and problems related to their traditional classification are analyzed. A general review of secular variations of such light-curve parameters studied in our previous papers as the period, amplitude, and mean brightness is given. Several types of Mira Ceti stars that differ in the secular period variation pattern are identified. A connection between the secular amplitude variations of certain variables with the effect of multiperiodicity is revealed. It is shown that the pattern of these variations and their numerical properties may be used to classify these variable stars.
      PubDate: 2014-06-01
      DOI: 10.3103/s0190271714010185
      Issue No: Vol. 110, No. 1 (2014)
       
  • Starspots and active regions on IN Com: UBVRI photometry and linear
           polarization
    • Authors: I. Yu. Alekseev; O. V. Kozlova
      Pages: 30 - 36
      Abstract: Abstract The activity of the variable star IN Com is considered using the latest multicolor UBVRI photometry and linear polarimetric observations carried out during a decade. The photometric variability of the star is fully described using the zonal spottedness model developed at the Crimean Astrophysical Observatory (CrAO). Spotted regions cover up to 22% of the total stellar surface, with the difference in temperatures between the quiet photosphere and the spot umbra being 600 K. The spots are located at middle and low latitudes (40°–55°). The intrinsic broad-band linear polarization of IN Com and its rotational modulation in the U band due to local magnetic fields at the most spotted (active) stellar longitudes were detected for the first time.
      PubDate: 2014-06-01
      DOI: 10.3103/s0190271714010045
      Issue No: Vol. 110, No. 1 (2014)
       
  • The stellar wind as a key to the understanding of the spectral activity of
           IN Com
    • Authors: O. V. Kozlova; I. Yu. Alekseev
      Pages: 37 - 44
      Abstract: Abstract We present long-term spectral observations (R = 20000) of IN Com in the region of the Hα, Hβ, and He I 5876 lines. One distinguishing characteristic of the stellar spectrum is the presence in the Hα line of an extended two-component emission with limits up to ±400 km/s. Emission parameters show the rotation modulation with the stellar rotation period and a significant variability on the long-term scale. Similar emissions are also observed in the Hβ and He I 5876 lines. Our results allow us to conclude that observational emission profiles are formed in an optically thin hot gas. This is a result of the presence of a circumstellar gas disk around IN Com. Its size does not exceed several stellar radii. The material for the disk is supported by the stellar wind from IN Com. The detected variability of Hα-emission parameters shows a clear connection with the photopolarimetric activity of the star. This fact allows us to associate the long-term spectral variability with cycles of stellar activity of IN Com.
      PubDate: 2014-06-01
      DOI: 10.3103/s0190271714010161
      Issue No: Vol. 110, No. 1 (2014)
       
  • Revisiting the issue of radiation spectra
    • Authors: Yu. I. Neshpor; A. V. Zhovtan
      Pages: 45 - 49
      Abstract: Abstract Based on the analysis of the published observational data on extragalactic and galactic sources in different energy ranges, it is concluded that there must be an emission generation phenomenon whereby the flux increases in a narrow energy range only, with higher-energy particles being more effectively accelerated.
      PubDate: 2014-06-01
      DOI: 10.3103/s0190271714010197
      Issue No: Vol. 110, No. 1 (2014)
       
  • Stellar flares
    • Authors: R. E. Gershberg
      Pages: 50 - 58
      Abstract: Abstract Different aspects of stellar flares as one of the events of stellar activity with different levels of similarity to solar-activity phenomena are briefly discussed: those which are understandable by means of scaling of solar events, those that do not occur on the Sun but general solar features allow us to understand them, and such stellar events that have not been understood as yet.
      PubDate: 2014-06-01
      DOI: 10.3103/s0190271714010148
      Issue No: Vol. 110, No. 1 (2014)
       
  • The absolute spectrophotometric catalog by Anita Cochran
    • Authors: V. I. Burnashev; B. A. Burnasheva; E. V. Ruban; E. I. Hagen-Torn
      Pages: 76 - 79
      Abstract: Abstract The absolute spectrophotometric catalog by Anita Cochran is presented in a machine-readable form. The catalog systematizes observations acquired at the McDonald Observatory in 1977–1978. The data are compared with other sources, in particular, the calculated broadband stellar magnitudes are compared with photometric observations by other authors, to show that the observational data given in the catalog are reliable and suitable for a variety of applications. Observations of variable stars of different types make Cochran’s catalog especially valuable.
      PubDate: 2014-06-01
      DOI: 10.3103/s0190271714010094
      Issue No: Vol. 110, No. 1 (2014)
       
  • On the variability of Vega
    • Authors: V. V. Butkovskaya
      Pages: 80 - 84
      Abstract: Abstract For 60 years Vega has been accepted as a standard star in the near infrared, optical, and ultraviolet ranges. However, a 21-year spectral and spectrophotometric variability of Vega has been revealed. Vega also demonstrates short-term unexplained variability. Recent spectropolarimetric studies have revealed a weak magnetic field on Vega. We analyze the results of 15-year observations performed at the Crimean Astrophysical Observatory and we hypothesize that the magnetic field variation is caused by stellar rotation. In the present work we summarize the results of investigations on the variability of Vega.
      PubDate: 2014-06-01
      DOI: 10.3103/s0190271714010100
      Issue No: Vol. 110, No. 1 (2014)
       
  • A method for the determination of the lithium abundance in sunspots:
           Observations for 2011
    • Authors: E. A. Baranovskii; S. A. Musorina; V. P. Tarashchuk
      Pages: 85 - 89
      Abstract: Abstract Sunspot spectra for LiI 6708Å lines and for several FeI and CaI lines were obtained. Observations were performed in January and in August, 2011 using the TST-2 telescope with a charge-coupled camera at the Crimean Astrophysical Observatory. The sunspot models were calculated by using the observing profiles of FeI and CaI lines. Lithium abundance was determined by using the calculated sunspot models and LiI 6708Å observed profiles; this equals log(N Li) = 0.98 and 0.95 (in the scale logA(H) = 12.0).
      PubDate: 2014-06-01
      DOI: 10.3103/s0190271714010069
      Issue No: Vol. 110, No. 1 (2014)
       
  • The rotation of sunspots in the solar active region NOAA 10930
    • Authors: O. S. Gopasyuk
      Pages: 90 - 94
      Abstract: Abstract The rotation of sunspots in the solar active region NOAA 10930 was investigated on the basis of the data on the longitudinal magnetic field and the Doppler velocities using magnetograms and dopplergrams taken with the Solar Optical Telescope installed aboard the HINODE mission. Under the assumption of axial symmetry, areally-mean vertical, radial, and azimuthal components of the magnetic field and velocity vectors were calculated in both sunspots. The plasma in the sunspots rotated in opposite directions: in the leading sunspot, clockwise, and in the following sunspot, counterclockwise. The magnetic flux tubes that formed sunspots of the active region on the solar surface were twisted in one direction, clockwise. Electric currents generated as a result of the rotation and twisting of magnetic flux tubes were also flowing in one direction. Azimuthal components of magnetic and velocity fields of both sunspot umbrae reached their maximum on December 11, 2006. By the start of the X3.4 flare (December 13, 2006), their values became practically equal to zero.
      PubDate: 2014-06-01
      DOI: 10.3103/s019027171401015x
      Issue No: Vol. 110, No. 1 (2014)
       
  • Characteristics of the solar flares and their spatial distribution in
           cycle 22 and the first half of cycle 23
    • Authors: Z. S. Akhtemov
      Pages: 95 - 100
      Abstract: Abstract This paper considers 3246 solar flares in the line Hα, which were accompanied by X-ray emission with a power f ≥ 5 × 10−6 Wm−2 in the solar cycle 22 (CR1797-CR1864). During 33 rotations, the specific power of X-ray emission of the flares increased monotonically by a factor of 4 from the cycle minimum up to its first maximum. The number of flares in each solar turnover rises non-monotonically and disproportionately to the relative number of sunspots. For the entire interval of time, one can identify several longitudinal intervals with increased flare activity. They exist during 5–10 rotations. The characteristics of the flares for 33 rotations in cycles 22 and 23 (CR1797-CR1961) are compared. It is concluded that the Sun is more active in cycle 22 than in cycle 23.
      PubDate: 2014-06-01
      DOI: 10.3103/s0190271714010021
      Issue No: Vol. 110, No. 1 (2014)
       
  • Physical conditions in the chromosphere of a two-strand solar flare with
           ejection
    • Authors: E. A. Baranovskii; N. N. Kondrashova; M. N. Pasechnik; V. P. Tarashchuk
      Pages: 101 - 104
      Abstract: Abstract Chromosphere layers of solar flares were investigated according to the observed profiles of the Hα line. A two-strand flare was observed on September 4, 1990. Spectra were obtained with the ATsU-26 solar horizontal telescope at Terskol Peak Observatory (3100 m). Spectra photometry is performed for two bright nodes of one strand of the flare. Some profiles are superposed to the ejection. The observed profiles are characterized by high emissions in the wings of the Hα line (up to 10–12 Å) under relatively low intensity in the center of Hα (r = 0.35–0.6). To explain such profile behavior we calculated flare models with two or three components. Separate components of the model correspond to unresolved details in the flare area and therefore the averaged profile is calculated. Emission in the far wings is explained by model components with deep heating of chromosphere layers. These occupy 5–12% of the total area. Noticeable emission asymmetry is explained by ray velocities of up to 70 km/s and more. The models are determined by agreement of the observed and calculated profiles. We processed several photometric profiles for seven observations. The temperature in the models with deep heating in the lower cromosphere is increased by 1000–2500 K with respect to the model with an undisturbed chromosphere VAL-C. The second feature of the observed profiles is their high asymmetry and shift with respect to the undisturbed profiles. This can be explained by the opposite motion of the material. We revealed that for the most of the profiles the line-of-sight velocities were directed to the observer in the upper chromosphere (10–100 km/s) and from the observer in the lower chromosphere (5–20 km/s).
      PubDate: 2014-06-01
      DOI: 10.3103/s0190271714010070
      Issue No: Vol. 110, No. 1 (2014)
       
  • Observational characteristics of the white-light flare of August 9, 2011
    • Authors: A. N. Babin; A. N. Koval’
      Pages: 105 - 113
      Abstract: Abstract We analyzed the monochromatic Hα and spectral (within a range of 6549–6579 Å) observational data for the 2B/X6.9 flare of August 9, 2011, that produced emission in the optical continuum. The morphology and evolution of the Hα flare and the position, time evolution, spectrum, and energetics of the white-light flare (WLF) kernels were studied. The following results were obtained: the flare erupted in the region of collision of a new and rapidly growing and propagating magnetic flux and a preexisting one. This collision led to a merger of two active bipolar regions. The white-light flare had a complex structure: no less than five kernels of continuum emission were detected prior to and in the course of the impulsive flare phase. Preimpulsive and impulsive white-light emission kernels belonged to different types (types II and I, respectively) of white-light flares. A close temporal agreement between the white-light emission maxima and the microwave emission peak was observed for the impulsive white-light emission kernels. The maximum flux, luminosity, and total energy emitted by the brightest impulsive WLF kernel equaled 1.4 × 1010 ergs cm−2 s−1, 1.5 × 1027 ergs/s, and 5 × 1029 ergs, respectively. The Hα profiles within the impulsive WLF kernels had broad wings (with a total extent of up to 26 Å and a half-width of up to 9 Å) and self-reversed cores. The profiles were symmetrical, but were shifted towards the red side of the spectrum. This is indicative of a downward motion of the entire emitting volume with a radial velocity of several tens of km/s. The intensity pattern in the wings did not correspond to the Stark one. The profiles were broadened by nonthermal turbulent motions with velocities of 150–300 km/s. The observed Hα profiles were analyzed and compared in their features to the profiles calculated for an intense heating of the chromosphere by nonthermal electrons accompanied by the development of a chromospheric condensation propagating downward. We came to the conclusion that the analyzed flare exhibited spectral features that may not be readily explained within the framework of chromosphere heating by a beam of nonthermal electrons.
      PubDate: 2014-06-01
      DOI: 10.3103/s0190271714010057
      Issue No: Vol. 110, No. 1 (2014)
       
  • Temporal variations in the large-scale magnetic field of the solar
           atmosphere at heights from the photosphere to the source surface
    • Authors: Z. S. Akhtemov; O. A. Andreeva; G. V. Rudenko; N. N. Stepanian; V. G. Fainstein
      Pages: 114 - 124
      Abstract: Abstract Calculations of the magnetic field in the potential approximation (using Bd technology (Rudenko, 2001)) were used to study the time variations of several parameters of the large-scale magnetic field in the solar atmosphere during the last four cycles. Synoptic maps (SMs) for the radial component Br of the calculated magnetic field were plotted at 10 heights between the solar surface (R = R ⊙) and the source (R = 2.5R ⊙). On these SMs, we marked the 10-degree latitudinal areas. The following (averaged within the zone) characteristics of the magnetic field were determined corresponding to these zones: Sp, Sm; S +fields , where Sp is the positive value of Br, Sm is the averaged modulus of the negative Br; S +fields is the percentage of latitudinal zones with positive Br. The analysis of temporal variations in the magnitude of S points to different origins of the large-scale magnetic field in the near-equatorial and polar regions of the solar atmosphere. The analysis of temporal variations of S +fields showed that there were almost no periods with a mixed polarity at R = 2.5R ⊙ during the 21st and 22nd solar cycles and in an ascending phase of the 23rd cycle. However, beginning from the maximum of the 23rd cycle, a mixed polarity in the equatorial region was observed until the end of the long minimum of activity. We hypothesized that this could be a precursor for a long minimum between the 23rd and 24th solar cycles. It was shown that during the maximum phase of the 24th solar cycle the magnetic field at R = R ⊙ is much less than that during the maximum phase of the 23rd cycle, and in the region from 55° to 75°, this difference reaches an order of magnitude.
      PubDate: 2014-06-01
      DOI: 10.3103/s0190271714010033
      Issue No: Vol. 110, No. 1 (2014)
       
  • X-class flares in the 24th solar activity cycle: Preflare and postflare
           conditions in the active region: Part 1. Analysis criteria and general
           comments
    • Authors: Yu. A. Fursyak
      Pages: 125 - 131
      Abstract: Abstract We analyzed the data on the flares of the X-ray class X in the 24th solar activity cycle. Several properties of the active regions (their morphological structure, the changes in the structure of the magnetic fields of spots, the evolution dynamics, etc.) were also analyzed with the object of identifying the factors that influence the flare activity of a group the most. In order to gather the maximum amount of experimental data, we used the observational data that cover various levels of the solar atmosphere that were obtained both by terrestrial and space (SOHO, SDO, XRT, Hinode, etc.) telescopes.
      PubDate: 2014-06-01
      DOI: 10.3103/s0190271714010136
      Issue No: Vol. 110, No. 1 (2014)
       
  • Autocollimating compensator for controlling aspheric optical surfaces. I
    • Authors: V. Yu. Terebizh
      Pages: 132 - 137
      Abstract: Abstract A compensator (null-corrector) for testing aspheric optical surfaces is proposed, which enables (1) independent verification of optical elements and assembling of the compensator itself, and (2) ascertaining the compensator position in a control layout for a specified aspheric surface. The autocollimating design allows significant reducing difficulties associated with practical use of lens compensators.
      PubDate: 2014-06-01
      DOI: 10.3103/s0190271714010239
      Issue No: Vol. 110, No. 1 (2014)
       
  • A fast wide-field telescope: Mechanical design
    • Authors: A. V. Dolgopolov
      Pages: 146 - 148
      Abstract: Abstract A mechanical design of a fast wide-field telescope with an entrance pupil that is 180 mm diameter, a focal length of 294 mm, and an angular field of view of 10° is described. Original construction solutions have been found for this type of system.
      PubDate: 2014-06-01
      DOI: 10.3103/s0190271714010112
      Issue No: Vol. 110, No. 1 (2014)
       
  • Adjustment of a tower solar telescope and spectrograph: A method manual
    • Authors: N. N. Stepanian; G. A. Sunitsa; V. M. Malashchuk
      Pages: 149 - 160
      Abstract: Abstract Questions of the mounting and adjustment of a tower solar telescope are considered through the example of the TST-2 telescope of the Crimean Astrophysical Observatory Scientific Research Institute. The authors describe the optical circuits of the telescope and spectrograph and list the basic requirements for the mutual arrangement of individual components of the telescope. Simple methods for adjusting elements of the telescope and spectrograph are described.
      PubDate: 2014-06-01
      DOI: 10.3103/s0190271714010227
      Issue No: Vol. 110, No. 1 (2014)
       
 
 
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