• Title/Summary/Keyword: PAK2

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Filter wheel design for CQUEAN II

  • Kim, Sanghyuk;Pak, Soojong;Lee, Hye-In;Im, Myunshin;Shin, Sang-Kyo
    • The Bulletin of The Korean Astronomical Society
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    • v.39 no.1
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    • pp.51.2-51.2
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    • 2014
  • CQUEAN(Camera for QUasars in EArly uNiverse) has been used at the 2.1 m Otto Struve Telescope of the McDonald Observatory since 2010. This camera is optimized at 0.7 - 1.1 um for the survey of Lyman break of high redshift (z > 5) quasars in the early universe. The current system has a filter wheel consist of seven (g', r', I', z', Y, Iz and Is) broad-band filters. We are upgrading this filter wheel to have 20 narrow band filters, with which we can take spectral energy distributions of targets. The new filter wheel consists of interchangeable cartridges for 50 mm square filters, a speed reducer unit, and a step motor. This new design of the large size filter wheel can be applied to other large format CCD cameras.

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Efficient Computation of Two-Phase Flow by Eulerian-Lagrangian Method Using Separate grids for the Particles and Flow Field (Eulerian-Lagrangian 방법에서 입자 및 유동 격자계 분리를 통한 2상 유동의 효율적 계산)

  • Pak S. I.;Lee J K.;Chang K. S.
    • 한국전산유체공학회:학술대회논문집
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    • 2003.08a
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    • pp.43-48
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    • 2003
  • When the Eulerian-Lagrangian method is used to analyze the particle laden two-phase flow, a large number of particles should be used to obtain statistically meaningful solutions. Then it takes too much time to track the particles and to average the particle properties in the numerical analysis of two-phase flow. The purpose of this paper is to reduce the computation time by means of a set of particle gird separate to the flow grid. Particle motion equation here is the simplified B-B-O equation, which is integrated to get the particle trajectories. Particle turbulent dispersion, wall collision, and wall roughness effects are considered but the two-way coupling effects between gas and particles are neglected. Particle laden 2-D channel flow is solved and it is shown that the computational efficiency is indeed improved by using the current method

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Near-IR Polarimetry Survey of the Large Magellanic Cloud: Relationship between the polarization degree and the color

  • Kim, Jaeyeong;Pak, Soojong;Kang, Wonseok;Choi, Minho
    • The Bulletin of The Korean Astronomical Society
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    • v.37 no.2
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    • pp.100.2-100.2
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    • 2012
  • We performed near-IR imaging polarimetry of the $5{\times}9$ fields (${\sim}39^{\prime}{\times}69^{\prime}$) around 30 Doradus in the Large Magellanic Cloud (LMC), using the InfraRed Survey Facility (IRSF). We obtained polarimetry data in the J, H, and Ks bands using the JHKs-simultaneous imaging polarimeter SIRPOL in 2008 December and 2011 December. With the reliable LMC field data which were selected using a bad-data-rejection algorithm, we measured Stokes parameters of point-like sources to derive the degree of polarization and the polarization position angle. We present physical relationship between the three bands using the photometric and the polarimetric properties of the sources.

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Adsorption Mechanism of Benzene and Its Derivatives on Graphite Surfaces (벤젠과 그 유도체들의 흑연표면 위의 흡착메카니즘)

  • Kim Yunsoo;Ahn, Young-Soo;Pak, Hyung-Suk;Chang, Sei-Hun
    • Journal of the Korean Chemical Society
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    • v.18 no.2
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    • pp.79-84
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    • 1974
  • Adsorption isotherms of benzene and its derivatives on Spheron 6, a graphitized carbon black, are obtained using a sensitive quartz beam microbalance. From the isotherms the molecular area of each adsorbate on Spheron 6 is calculated on the basis of nitrogen area of 16.2 $A^2$. the results show that the molecules of each species are adsorbed on Spheron 6 with the planes of benzene rings lying flat on the surfaces and doing hindered rotation.

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An Experimental Study on the Double Diffusive Thermohaline System (열-염분 이중확산계에 관한 실험적 연구)

  • Pak, Hi-Yong;Lim, Kyung-Bin
    • Solar Energy
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    • v.6 no.2
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    • pp.15-21
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    • 1986
  • In this study, an experimental double diffusive thermohaline system heated from below was constructed and the phenomena of each layer developed in the system were observed. The experiment was performed with the initial salt concentration gradient of $-436.2kg/m^4$ and the net heat flux of approximately $176w/m^2$. An electroconductivity-temperature probe was made and used for the measurements of salt concentration. As the result of this study, it was found that the salt concentration decreased in the bottom mixed layer and increased in the top mixed layer during the experiment while the salt concentration gradient in the diffusive layer unchanged. It was also found that the interfacial boundary layers were due largely to variations in salt concentration rather than temperature.

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MEDIUM RESOLUTION SPECTRAL LIBRARY OF LATE-TYPE STELLAR TEMPLATES IN NEAR-INFRARED BAND

  • Nguyen, Huynh Anh Le;Pak, Soo-Jong;Im, Myung-Shin;Kang, Won-Seok;Lee, Sang-Gak;Ho, Luis C.;Pyo, Tae-Soo;Jaffe, Daniel T.
    • The Bulletin of The Korean Astronomical Society
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    • v.36 no.1
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    • pp.69.2-69.2
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    • 2011
  • We present medium resolution spectra in the near-infrared (IR) band 1.4-1.8 microns at a resolving power of R = 5000-10000 of template stars in G, K, and M types with luminosity classes of III observed by the echelle spectrometer, IRCS, at the SUBARU 8.2 m telescope. Identification of lines in the template star spectra has been completed base on the reference of Arcturus spectrum. We measured equivalent width (EW) of the lines, and analyze the trends of EW through the stellar spectral types.

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Imaging System Wavefront Analysis Using Ronchi Test

  • Lee, Sunwoo;Park, Woojin;Yu, Joonkyu;Pak, Soojong
    • The Bulletin of The Korean Astronomical Society
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    • v.43 no.2
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    • pp.56.2-56.2
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    • 2018
  • Ronchi test is an optical test to check the quality of an imaging system. Wavefront of the optical system can be obtained from the Ronchi patterns. In this poster, we present the Ronchi test module and the optical quality evaluation results. The test module consists of a light source, a pinhole, a beam splitter, a Ronchi ruling and a flat mirror. The test module can be simply adapted to any optical systems. We compare measured surface data for both aluminum and glass parabolic mirrors by analyzing the Ronchi patterns.

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Narrowbore high-performance liquid chromatographic method for the determination of cetirizine in plasma using column switching

  • Hyun, Myung-Ja;Ban, Eunmi;Woo, Jong-Soo;Kim, Chong-Kook
    • Proceedings of the PSK Conference
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    • 2002.10a
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    • pp.398.2-398.2
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    • 2002
  • A column switching HPLC assay was developed to allow the separation and quantitation of cetirizine in human plasma by ultraviolet (UV) detection. Plasma samples were prepared by liquid-liquid extraction. After drying, the residue was reconstituted in 20 mM phosphate buffer (pH 2.8) containing 15% acetonitrile. The samples were initially injected onto a clean-up Capcell Pak MF C18 column. (50 mm $\times$ 4.6 mm I.D.), and the chromatographic region containing the peaks of interest was followed in an analytical C18 microcolumn (250 mm$\times$1.5 mm I. D.) via column switching device. (omitted)

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Analysis of DA-6034. a New Flavonoid Derivative in Biological Fluids by Fluorescence Detector

  • Jang, Ji-Myun;Park, Kyung-Jin;Lee, Jong-Jin;Kim, Dong-Goo;Shim, Hyun-Joo;Son, Mi-Won;Kim, Dong-Sung;Kim, Soon-Hoe;Yoo, Moo-Hi
    • Proceedings of the PSK Conference
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    • 2002.10a
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    • pp.403.2-403.2
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    • 2002
  • A high performance liquid chromatographic method was developed for the determination of DA-6034 in biological fluids using fluorescence detector. The method involved deproteinization of biological sample with the same volume of acetonitrile, 0.2M zinc sulphate. and 0.15M barium hydroxide. The aliquot of supernatant was injected onto Nova-pak C18 column and detected by fluorescence detector. Emission and excitation wavelength of detector were 336nm and 440nm. (omitted)

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Overview of Modeling Process using Giant Magellan Telescope Software Development Kit

  • Han, Jimin;Kim, Changgon;Pi, Marti;Filgueira, Josema;Cox, Marianne;Peng, Chien;Roman, Alfonso;Molgo, Jordi;Schoenell, William;Swett, Hector;Thanasekaran, Divya;Kurkdjian, Pierre;plubell, Charles;Ji, Tae-Geun;Lee, Hye-In;Pak, Soojong
    • The Bulletin of The Korean Astronomical Society
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    • v.44 no.2
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    • pp.46.2-46.2
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    • 2019
  • The software group in Giant Magellan Telescope Organization (GMTO) is developing the GMT Software Development Kit (SDK) for the device control and the telescope operations. The SDK is dived into the modeling and the operation defining. In the modeling process, Domain Specific Language (DSL) can validate the availability of a model and generate a skeleton code automatically. After the modeling, the developer can simply define the device operation. All devices are connected via EtherCAT, and the SDK simplifies the network connection. This presentation will give an overview of the modeling process and development examples using the GMT SDK.

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