Jin Hee An

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Xyloglucan oligosaccharides from cotton cell walls and tamarind seeds were derivatized with 2-aminopyridine and subsequently separated by reversed-phase chromatography (r.p.c.) using an octadecylsilyl silica stationary phase and aqueous-organic eluents with 0.01% (v/v) trifluoroacetic acid. The chromatographic behavior of the 2-pyridylamino derivatives of(More)
The lightcurve of PA-99-N2, one of the recently announced microlensing candidates towards M31, shows small deviations from the standard Paczyński form. We explore a number of possible explanations, including correlations with the seeing, the parallax effect and a binary lens. We find that the observations are consistent with an unresolved RGB or AGB star in(More)
Emissions in East Asia for 1993 by administrative units and source types are estimated to support regional emission assessments and transport modeling studies. Total emission of SOx, NOx, soil NOx, N2O, and NH3 are 24,150 kton/year, 12,610 kton/year, 1,963 kton/year, 908kton/year, and 8,263 kton/year, respectively. China’s emission contribution is the(More)
There is good evidence from N-body simulations that the velocity distribution in the outer parts of halos is radially anisotropic, with the kinetic energy in the radial direction roughly equal to the sum of that in the two tangential directions. We provide a simple algorithm to generate such cosmologically important distribution functions. Introducing(More)
This paper provides a complete theoretical treatment of the point-mass lens perturbed by constant external shear, often called the Chang-Refsdal lens. We show that simple invariants exist for the products of the (complex) positions of the four images, as well as moment sums of their signed magnifications. The image topographies and equations of the caustics(More)
When the gravitational lensing potential can be approximated by that of a circularly symmetric system affected by weak perturbations, it is found that the shape of the resulting (tangential) caustics is entirely specified by the local azimuthal behaviour of affecting perturbations. This provides common mathematical groundwork for understanding the problems(More)
We analyze PLANET photometric observations of the caustic-crossing binary-lens microlensing event, EROS BLG-2000-5, and find that modeling the observed light curve requires incorporation of the microlens parallax and the binary orbital motion. The projected Einstein radius (r̃E = 3.61±0.11AU) is derived from the measurement of the microlens parallax, and we(More)
The POINT–AGAPE (Pixel-lensing Observations with the Isaac Newton Telescope– Andromeda Galaxy Amplified Pixels Experiment) survey is an optical search for gravitational microlensing events towards the Andromeda galaxy (M31). As well as microlensing, the survey is sensitive to many different classes of variable stars and transients. Here we describe the(More)
It is shown that, if the tracer population is supported by a spherical dark halo with a core or a cusp diverging more slowly than that of a singular isothermal sphere, the logarithmic cusp slope γ of the tracers must be given exactly by γ = 2β where β is their velocity anisotropy parameter at the center unless the same tracers are dynamically cold at the(More)
Spherical models with constant velocity anisotropy β have distribution functions depending on binding energy E and angular momentum L of the form f (E, L) = L−2β fE(E). An inversion for the unknown function fE (E) is straightforward to derive and reduces to Eddington’s famous algorithm for isotropic models (β = 0). Importantly, if the anisotropy parameter(More)