2,534 research outputs found
Proto-Model of an Infrared Wide-Field Off-Axis Telescope
We develop a proto-model of an off-axis reflective telescope for infrared
wide-field observations based on the design of Schwarzschild-Chang type
telescope. With only two mirrors, this design achieves an entrance pupil
diameter of 50 mm and an effective focal length of 100 mm. We can apply this
design to a mid-infrared telescope with a field of view of 8 deg X 8 deg. In
spite of the substantial advantages of off-axis telescopes in the infrared
compared to refractive or on-axis reflective telescopes, it is known to be
difficult to align the mirrors in off-axis systems because of their asymmetric
structures. Off-axis mirrors of our telescope are manufactured at the Korea
Basic Science Institute (KBSI). We analyze the fabricated mirror surfaces by
fitting polynomial functions to the measured data. We accomplish alignment of
this two-mirror off-axis system using a ray tracing method. A simple imaging
test is performed to compare a pinhole image with a simulated prediction.Comment: 14 pages, 16 figure
Stellar Contents and Globular Cluster Candidates in the Sculptor Group Galaxy NGC 300
We present UBVI CCD photometry of the stellar contents and globular
cluster(GC) candidates in the spiral galaxy NGC 300 in the Sculptor group.
Color-magnitude diagrams for 18 OB associations having more than 30 member
stars are presented. The slope of the initial mass function for the bright
stars in NGC 300 is estimated to be Gamma = -2.6 +/- 0.3. Assuming the distance
to NGC 300 of (m-M)_0 = 26.53 +/- 0.07, the mean absolute magnitude of three
brightest blue stars is obtained to be = -8.95 mag. We have
performed search for GCs in NGC 300 and have found 17 GC candidates in this
galaxy. Some characteristics of these GC candidates are discussed.Comment: 24 pages(AASLaTeX), 14 Postscript figures, Accepted for publication
in the Journal of the Korean Astronomical Society, 2002 March issue, Typos
Correcte
Acute Interstitial Pneumonia in Siblings: A Case Report
Acute interstitial pneumonia (AIP) is a rapidly progressive condition of unknown cause that occurs in a previously healthy individual and produces the histologic findings of diffuse alveolar damage. Since the term AIP was first introduced in 1986, there have been very few case reports of AIP in children. Here we present a case of AIP in a 3-yr-old girl whose other two siblings showed similar radiologic findings. The patient was confirmed to have AIP from autopsy showing histological findings of diffuse alveolar damage and proliferation of fibroblasts. Her 3-yr-old brother was also clinically and radiologically highly suspected as having AIP, and the other asymptomatic 8-yr-old sister was radiologically suspected as having AIP
Epitaxially strained ultrathin LaNiO/LaAlO and LaNiO/SrTiO superlattices: a density functional theory + study
By employing first-principles electronic structure calculations we
investigate nickelate superlattices [LaNiO]/[LaAlO] and
[LaNiO]/[SrTiO] with (001) orientation under epitaxial tensile
strain. Within density functional theory augmented by mean-field treatement of
on-site electronic correlations, the ground states show remarkable dependence
on the correlation strength and the strain. In the weakly and intermediately
correlated regimes with small epitaxial strain, the charge-disproportionated
insulating states with antiferromagneitc order is favored over the other
orbital and spin ordered phases. On the other hand, in the strongly correlated
regime or under the large tensile strain, ferromagnetic spin states with
Jahn-Teller orbital order become most stable. The effect from polar interfaces
in LaNiO]/[SrTiO] is found to be noticeable in our
single-layered geometry. Detailed discussion is presented in comparison with
previous experimental and theoretical studies.Comment: 9 pages, 8 figure
Optimality and Duality for Multiobjective Fractional Programming Involvingn-Set Functions
AbstractWe consider a multiobjective fractional programming problem (MFP) involving vector-valued objectiven-set functions in which their numerators are different from each other, but their denominators are the same. By using the concept of proper efficiency, we establish optimality conditions and duality relations for our problem (MFP) under convexity assumptions on objective and constrained functions
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