Spectroscopic Studies of the Solar Corona. IV. Physical Properties of Coronal Structure

2003 ◽  
Vol 585 (1) ◽  
pp. 516-523 ◽  
Author(s):  
Jagdev Singh ◽  
Kiyoshi Ichimoto ◽  
Takashi Sakurai ◽  
S. Muneer
Keyword(s):  
Physical Properties ◽  
Solar Corona ◽  
Spectroscopic Studies ◽  
Coronal Structure

Physical Properties of Human Polynucleotide Kinase:  Hydrodynamic and Spectroscopic Studies†

Biochemistry ◽  
2001 ◽  
Vol 40 (43) ◽  
pp. 12967-12973 ◽  
Author(s):  
Rajam S. Mani ◽  
Feridoun Karimi-Busheri ◽  
Carol E. Cass ◽  
Michael Weinfeld
Keyword(s):  
Physical Properties ◽  
Spectroscopic Studies ◽  
Polynucleotide Kinase

A Discussion on the physics of the solar atmosphere - Spectroscopic studies of the solar corona at x-ray wavelengths

1976 ◽  
Vol 281 (1304) ◽  
pp. 383-390 ◽  
Keyword(s):  
Spatial Distribution ◽  
Solar Corona ◽  
Spatial Variation ◽  
Resonance Line ◽  
Active Regions ◽  
Resonance Scattering ◽  
Spectroscopic Studies ◽  
Line Of Sight ◽  
X Ray ◽  
Forbidden Transitions

The spatial distribution of the emission in several X-ray lines is discussed with emphasis on temperature dependence and association with active regions. New results are presented for the trio of helium-like O vii lines which demonstrate (1) a spatial variation in the density dependent forbidden to intersystem line ratio, and (2) a strong spatial variation in the intensity of the O vii resonance line relative to the optically forbidden transitions. The second effect appears to be caused by resonance scattering by material in the line of sight.

Synthesis, physical properties and spectroscopic studies of oxamato (−1) lanthanide(III) complexes

1990 ◽  
Vol 158 (1) ◽  
pp. 1-14 ◽  
Author(s):  
V Lazaridou ◽  
S.P Perlepes ◽  
J.M Tsangaris ◽  
Th.F Zafiropoulos
Keyword(s):  
Physical Properties ◽  
Spectroscopic Studies

scholarly journals Spectroscopic Studies of the Solar Corona II. Properties of Green and Red Emission Lines in Open and Closed Coronal Structures

2002 ◽  
Vol 54 (5) ◽  
pp. 793-806 ◽  
Author(s):  
Jagdev Singh ◽  
Takashi Sakurai ◽  
Kiyoshi Ichimoto ◽  
Yoshinori Suematsu ◽  
Aki Takeda
Keyword(s):  
Solar Corona ◽  
Spectroscopic Studies ◽  
Emission Lines ◽  
Red Emission ◽  
Coronal Structures

Interaction between Carboxylated Nitrile Rubber and Precipitated Silica: Role of (3-Aminopropyl)Triethoxysilane

1996 ◽  
Vol 69 (4) ◽  
pp. 637-647 ◽  
Author(s):  
Sumanda Bandyopadhyay ◽  
P. P. De ◽  
D. K. Tripathy ◽  
S. K. De
Keyword(s):  
Physical Properties ◽  
Coupling Agent ◽  
Spectroscopic Studies ◽  
Nitrile Rubber ◽  
Dynamic Mechanical ◽  
Precipitated Silica ◽  
Silica Filler ◽  
Bound Rubber ◽  
Rubber Filler

Abstract On the basis of measurements of bound rubber and physical properties and the results of Monsanto rheometer, dynamic mechanical and infrared spectroscopic studies, it is observed that strong rubber-filler interaction occurs between XNBR and precipitated silica filler. During molding, XNBR was found to be crosslinked by the filler surface through the formation of primary bonds. The coupling agent, namely (3-aminopropyl)triethoxysilane facilitates the formation of rubber-filler bonds at the expense of filler-filler networks, leading to improved dispersion and enhanced degree of crosslinking.

scholarly journals The R136 star cluster dissected with Hubble Space Telescope/STIS – II. Physical properties of the most massive stars in R136

2020 ◽  
Vol 499 (2) ◽  
pp. 1918-1936 ◽  
Author(s):  
Joachim M Bestenlehner ◽  
Paul A Crowther ◽  
Saida M Caballero-Nieves ◽  
Fabian R N Schneider ◽  
Sergio Simón-Díaz ◽  
...  
Keyword(s):  
Physical Properties ◽  
Hubble Space Telescope ◽  
Massive Stars ◽  
Mass Function ◽  
Large Magellanic Cloud ◽  
Spectroscopic Studies ◽  
Initial Mass Function ◽  
Space Telescope ◽  
Power Law Exponent ◽  
Red Supergiants

ABSTRACT We present an optical analysis of 55 members of R136, the central cluster in the Tarantula Nebula of the Large Magellanic Cloud. Our sample was observed with STIS aboard the Hubble Space Telescope, is complete down to about 40 M⊙, and includes seven very massive stars with masses over 100 M⊙. We performed a spectroscopic analysis to derive their physical properties. Using evolutionary models, we find that the initial mass function of massive stars in R136 is suggestive of being top-heavy with a power-law exponent γ ≈ 2 ± 0.3, but steeper exponents cannot be excluded. The age of R136 lies between 1 and 2 Myr with a median age of around 1.6 Myr. Stars more luminous than log L/L⊙ = 6.3 are helium enriched and their evolution is dominated by mass-loss, but rotational mixing or some other form of mixing could be still required to explain the helium composition at the surface. Stars more massive than 40 M⊙ have larger spectroscopic than evolutionary masses. The slope of the wind–luminosity relation assuming unclumped stellar winds is 2.41 ± 0.13 which is steeper than usually obtained (∼1.8). The ionizing ($\log Q_0\, [{\rm ph/s}] = 51.4$) and mechanical ($\log L_{\rm SW}\, [{\rm erg/s}] = 39.1$) output of R136 is dominated by the most massive stars ($\gt 100\, \mathrm{ M}_{\odot }$). R136 contributes around a quarter of the ionizing flux and around a fifth of the mechanical feedback to the overall budget of the Tarantula Nebula. For a census of massive stars of the Tarantula Nebula region, we combined our results with the VLT-FLAMES Tarantula Survey plus other spectroscopic studies. We observe a lack of evolved Wolf–Rayet stars and luminous blue and red supergiants.

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