• Title/Summary/Keyword: P-V curve

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Photoelectric Observation of the Long-Period Eclipsing Binaries at Yonsei University Observatory

  • Nha, Il-Seong;Lee, Yong-Sam;Chun, Yong-Woo;Kim, Ho-Il;Kim, Young-Soo
    • Journal of Astronomy and Space Sciences
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    • v.3 no.1
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    • pp.1-13
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    • 1986
  • A long-term project(ten-year ; 1982-92) for the photoeletric observation in the UBV passbands of selected eclipsing binaries with P$\geq$10 days has initiated at Yonsei University Observatory using 40-cm and 61-cm reflectors. the instrumentatio used and the observation techniques and the reduction procedures applied to this investiagation are described. Out of 39 program stars, successful results have been obtained during our first two years for the 11 stars listed below, with the orbital period in days in the parenthesis, and the incomplete light curves of these stars are presented. SX Cas (36.57) AQ Cas (11.72) UU Cnc (96.71) RY Gem (9.30) V373 Cas (13.42) NY Cep (15.28) RX Cas (32.32) V396 Cas (15.28) ZZ Cnc (25.60) Zet Aur (982.2) Eps Aur (9885.) For the rest of the stars, the observations made in the first two years are not sufficient to attempt any meaning light curve construction ; some of the data are too fragmented and others show large scatter.

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Quantitative Determination of Dioscin from Dioscorea Rhizoma (산약(山藥; Dioscorea Rhizoma)으로부터 Dioscin의 분리 분석)

  • Son, Kun-Ho;Kim, Jong-Yeon;Kim, Soon-Dong;Lim, Sang-Kyu;Nam, Doo-Hyun
    • Korean Journal of Pharmacognosy
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    • v.37 no.1 s.144
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    • pp.33-36
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    • 2006
  • The quantitative analytical method for the content of dioscin in Dioscorea rhizoma using a high performance liquid chromatography(HPLC) system was established for its quality control. After extracting Discorea rhizoma flour with ethanol, dioscin was separated though an ODS column with a flow rate of 1.0ml/min of acetonnitril-methanol-0.01 M phosphate buffer (pH 5.0)(6:3:1, v/v%), and the amount of dioscin was detected at 210nm. Relation time of dioscin in HPLC chromatogram were about $7.45{\pm}0.34\;min$ and calibration curve showed good linearity at concentrations from 0.1 to 2.0 mg/ml of dioscin. When 5 commercial Dioscorea rhizoma flours were analyzed by HPLC, the peak for dioscin was well separated from others in ethanol extract of Dioscorea rhizoma, and the amount of dioscin was in the range from 0.076 to 0.142(w/w)%.

Simplified HPLC Method for the Determination of Mirtazapine in Human Plasma and Its Application to Single-dose Pharmacokinetics

  • Gwak Hye-Sun;Lee Na-Young;Chun In-Koo
    • Biomolecules & Therapeutics
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    • v.14 no.1
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    • pp.40-44
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    • 2006
  • Mirtazapine is an antidepressant agent with dual action on both the noradrenergic and serotonergic neurotransmitter systems. A simple high performance liquid chromatographic method has been developed and validated for the quantitative determination of mirtazapine in human plasma. A reversed-phase Cl8 column was used for the determination of mirtazapine with a mobile phase composed of 0.01M ammonium acetate solution (pH 4.2) and acetonitrile (75:25, v/v%) at a flow rate of 1.2 mL/min. Terazosin hydrochloride was used as an internal standard. The fluorescence detector was set at excitation and emission wavelengths of 290 and 350 nm, respectively. Intra- and inter-day precision and accuracy were acceptable for all quality control samples including the lower limit of quantification of 3 ng/mL. Mirtazapine was stable in human plasma under various storage conditions. This method was used successfully for a pharmacokinetic study using plasma samples after oral administration of a single 30 mg dose as mirtazapine base to 8 healthy volunteers. The maximum plasma concentration of mirtazapine was $64.1{\pm}28.0ng/mL$ at 1.8 h, and the area under the curve and elimination half-life were calculated to be $674.1{\pm}218.5ng\;h/mL\;and\;23.4{\pm}3.8h$, respectively.

Optimization of remote plasma enhanced chemical vapor deposition oxide deposition process using orthogonal array table and properties (직교배열표를 쓴 remote-PECVD 산화막형성의 공정최적화 및 특성)

  • 김광호;김제덕;유병곤;구진근;김진근
    • Electrical & Electronic Materials
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    • v.8 no.2
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    • pp.171-175
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    • 1995
  • Optimum condition of remote plasma enhanced chemical vapor deposition using orthogonal array method was chosen. Characteristics of oxide films deposited by RPECVD with SiH$_{4}$ and N$_{2}$O gases were investigated. Etching rate of the optimized SiO$_{2}$ films in P-etchant was about 6[A/s] that was almost the same as that the high temperature thermal oxide. The films showed high dielectric breakdown field of more than 7[MV/cm] and a resistivity of 8*10$^{13}$ [.ohmcm] around at 7[MV/cm]. The interface trap density of SiO$_{2}$/Si interface around the midgap derived from the high frequency C-V curve was about 5*10$^{10}$ [/cm$^{2}$eV]. It was observed that the dielectric constant of the optimized SiO$_{2}$ film was 4.29.

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Follow-up Observations of Transiting Planets using Heavy Defocus Technique

  • Hinse, Tobias C.;Han, Wonyong;Yoon, Joh-Na;Lee, Jae Woo;Lee, Chung-Uk;Park, Jang-Ho;Kim, Chun-Hwey
    • The Bulletin of The Korean Astronomical Society
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    • v.38 no.1
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    • pp.56.1-56.1
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    • 2013
  • We have carried out follow-up observations of transiting extrasolar planets using small- to medium-sized reflectors located in Korea. Using the 0.60m telescope stationed at CbNUO (Chungbuk National University Observatory) we have achieved a photometric precision of 1.48 milli-magnitudes (root-mean-square scatter of data) of a HAT-P-09b (transit duration of 3.43 hrs) transit light curve (transit depth ~ 1.3%) with V=12.3 mag for the host star. We expect a photometric precision of 1.0 - 1.2 milli-magnitude for brighter targets (V ~ 10 - 11 mag). The transit technique and its application will be outlined. The results of test observations will be presented and the defocus technique will be discussed.

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Growth and Effect of Thermal Annealing for ZnIn2S4 Single Crystal Thin Film by Hot Wall Epitaxy (Hot Wall Epitaxy (HWE)법에 의한 ZnIn2S4 단결정 박막 성장과 열처리 효과)

  • Park, Chang-Sun;Hong, Kwang-Joon
    • Korean Journal of Materials Research
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    • v.18 no.6
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    • pp.318-325
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    • 2008
  • Single crystal $ZnIn_2S_4$ layers were grown on thoroughly etched semi-insulating GaAs(100) substrate at $450^{\circ}C$ with hot wall epitaxy (HWE) system by evaporating $ZnIn_2S_4$ source at $610^{\circ}C$. The crystalline structure of the single crystal thin films was investigated by the photoluminescence (PL) and double crystal X-ray rocking curve (DCRC). The temperature dependence of the energy band gap of the $ZnIn_2S_4$ obtained from the absorption spectra was well described by the Varshni's relation, $E_g(T)=2.9514\;eV-(7.24{\times}10^{-4}\;eV/K)T^2/(T+489\;K)$. After the as-grown $ZnIn_2S_4$ single crystal thin films were annealed in Zn-, S-, and In-atmospheres, the origin of point defects of $ZnIn_2S_4$ single crystal thin films has been investigated by the photoluminescence (PL) at 10 K. The native defects of $V_{Zn}$, $V_S$, $Zn_{int}$, and $S_{int}$ obtained by PL measurements were classified as a donors or acceptors type. And we concluded that the heat-treatment in the S-atmosphere converted $ZnIn_2S_4$ single crystal thin films to an optical p-type. Also, we confirmed that In in $ZnIn_2S_4$/GaAs did not form the native defects because In in $ZnIn_2S_4$ single crystal thin films existed in the form of stable bonds.

Determination of Ketorolac in Human Serum by High-performance Liquid Chromatography

  • Chun, In-Koo;Kang, Hyun-Hee;Gwak, Hye-Sun
    • Archives of Pharmacal Research
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    • v.19 no.6
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    • pp.529-534
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    • 1996
  • A high-performance liquid chromatographic (HPLC) assay has been developed for the determination of ketorolac in human serum using a new extraction method with a good recovery. Human serum samples (1.0 ml) spiked with known concentrations of ketorolac tromethamine and 10${\mu}g$ of ketoprofen as the internal standard (IS) were acidified with 200${\mu}l$ of 1 N HCl and extracted with 7 ml of n-hexane-ether (7:3 v/v). Extracts were centrifuged and organic layer was back-extracted with 400${\mu}l$ of 0.1% tromethamine solution. Twenty .mu.l of centrifuged aqueous layer was injected onto a reversed-phase octyl column and eluted with a mixture of acetonitrile, water, methanol, and triethylamine [35:55:10:0.1 (v/v), pH 3.0] at a flow rate of 1.0 ml/min. Ultraviolet detection of ketorolac and IS was carried out at 300 nm. The calibration curve obtained using peak area ratios showed a good linearity (in concentration range 10-150 ng/ml $r^2$=O.9944; in range 50-2000 ng/ml, r$^{2}$=0.9998). The mean intra-day accuracy and precision for this HPLC method were found to be 3.6 and 3.7%, respectively. The mean inter-day accuracy and precision were found to be 4.0 and 3.7%, respectively, in the concentration range 50-2000 ng/ml. The recovery of ketorolac from serum was 92.0 $({\pm}5.7)$ % at the concentration of 100 ng/ml. This method proved to be readily applicable to the assay of ketorolac in human serum.

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A Study of Dosimetric Characteristics of a Diamond Detector for Small Field Photon Beams (광자선 소조사면에 대한 다이아몬드 검출기의 선량특성에 관한 연구)

  • Loh, John-K.;Park, Sung-Y.;Shin, Dong-O.;Kwon, Soo-I.;Lee, Kil-D.;Kim, Woo-C.;Cho, Young-K.
    • Journal of Radiation Protection and Research
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    • v.24 no.4
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    • pp.195-203
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    • 1999
  • It is difficult to determine dosimetric characteristics for small field photon beams since such small fields do not achieve complete lateral electronic equilibrium and have steep dose gradients. Dosimetric characteristics of small field 4, 6, and 10 MeV photon beams have been measured in water with a diamond detector and compared to measurements using small volume cylindrical and plane parallel ionization chambers. Percent depth dose (PDD) and beam profiles for 6 and 10 MeV photon beams were measured with diamond detector and cylindrical ion chamber for small fields ranging from $1{\times}1\;to\;4{\times}4cm^2$. Total scatter factors($S_{c,p}$) for 4, 6, and 10 MeV photon beams were measured with diamond detector, cylindrical and plane parallel ion chambers for small fields ranging from $1{\times}1\;to\;4{\times}4cm^2$. The $S_{c,p}$ factors obtained with three detectors for 4, 6, and 10 MeV photon beams agreed well ($\pm1.2%$) for field sizes greater than $2{\times}2,\;2.5{\times}2.5,\;and\;3{\times}3\;cm^2$, respectively. For smaller field sizes, the cylindrical and plane parallel ionization chambers measure a smaller $S_{c,p}$ factor, as a result of the steep dose gradients across their sensitive volumes. The PDD values obtained with diamond detector and cylindrical ionization chamber for 6 and 10MeV photon beams agreed well ($\pm1.5%$) for field sizes greater than $4{\times}4\;cm^2$. For smaller field sizes, diamond detector produced a depth-dose curve which had a significantly shallower falloff than that obtained from the measurements of relative depth-dose with a cylindrical ionization chamber. For the measurements of beam profiles, a distortion in terms of broadened penumbra was observed with a cylindrical ionization chamber since diamond detector exhibited higher spatial resolution. The diamond detector with small sensitive volume, near water equivalent, and high spatial resolution is suitable detector compared to ionization chambers for the measurements of small field photon beams.

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A Study on Performance of PEMFC with Variations on Stack Temperature and Mass Flow Rate (스택온도 및 유량변화에 따른 PEMFC의 출력특성 연구)

  • Park, Se-Joon;Choi, Yong-Sung;Lee, Kyung-Sup
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.11a
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    • pp.140-140
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    • 2009
  • The polymer electrolyte membrane fuel cell(PEMFC) with the advantages of low-operating temperature, high current density, low cost and volume, fast start-up ability, and suitability for discontinuous operation becomes the most reasonable and attractive power system for transportation vehicle and micro-grid power plant in a household. 200W PEM-type FCs system was integrated by this study, then the electrical characteristics and diagnosis of the fuel cell were analyzed with variations on mass flow rate and stack temperature. The ranges of the variations are $20{\sim}70^{\circ}C$ on stack temperature and 1~8L/min on $H_2$ volume.

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$J_{c}$ control ofNb/$Al_{2}$$O_{3}$ /Nb Josephson junction (Nb/$Al_{2}$$O_{3}$ /Nb 조셉슨 접합의 임계전류밀도 제어)

  • 김규태;홍현권;이상길;이규원
    • Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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    • 2002.02a
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    • pp.10-12
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    • 2002
  • Single Josephson junctions of 50 $\mu$m $\times$ 50 $\mu$m were fabricated for several oxidation conditions to investigate controllabilities of critical current density ($J_{c}$) with the standard KRISS processes. Considering the self-field effect suppressing the observed critical current ($I_{c}$) at high $J_{c}$ region, we could reasonably estimate $J_{c}$ values from I-V observations. The dependence of the estimated $J_{c}$ as a function of exposure, which is equal to pressure(P) times time(t), was well fitted to a curve of $J_{c}$ ~ $(Pt)^{-0.36}$. The maximum $J_{c}$ value at the controllability margin was found to be 4 kA/$cm^{2}$ with the current equipment set up.

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