채층 활동이 강한 별들의 분광선

강영운,김호일,이우백,오규동,KANG YOUNG WOON,KIM HOIL,LEE WOO BAIK,OH KYU DONG 한국천문학회 2000 天文學論叢 Vol.15 No.suppl1

We have reviewed the magnetic activity in close binaries. Solar like magnetic activity indicators such as photometric spots, chromo spheric emission, coronal X-ray and radio emission, and flare activity are commonplace in many cool stars with convective envelopes. Using the UV spectra we confirmed the strength of stellar activity increases with more rapid rotation and later spectral types which corresponds to the increasing depth of the star's convective envelope. Apart from very young stellar objects such as T Tauri stars, the stars with the highest levels of activity are close binary systems composed of cool stars, i.e., the chromospherically active binaries such as RS CVn, BY Dra, W UMa and related systems. The IUE low and high dispersion spectra of V711 Tau, VW Cep and SW Lac are used for ultraviolet photometry and for a variation study of chromospheric activity. Evidence of chromospherically activity is indicated by the intensity variation of the Mg II emission line with orbital phase.

Asymmetric Light curves of Contact and Near-Contact Binaries

강영운,Rittipruk, Pakakaew,Kang, Young-Woon 한국천문학회 2012 天文學會報 Vol.37 No.2

We attempt to investigate the main reason of the asymmetrical light curves of contact and near-contact eclipsing binary base on the hypothesis that cool spot was produced on late type star while hot spot was produced from transferred material from their companion star hitting surface. We select 7 eclipsing binary systems which showed asymmetric light curves and mass transfer. Period variation and mass transfer rate were obtained from O-C diagram. Radial velocity curves and light curves of those 7 eclipsing binary system were adopted from available literature in order to obtain the absolute dimension. For four contact eclipsing binary system (AD Phe, EZ Hya, AG Vir and VW Boo), their component stars belonged to spectral type G to K was fitted by cool spot model. While the other two near-contact systems (RT Scl and V1010 Oph) and one contact system (SV Cen) was fitted by cool spot model. The densities of the materials are adopted from stellar model which calculate by stellar structure code. The calculated spot temperature turns out to agree with the photometric solution but there are no correlate between period variation rate and type of spot.

Fundamental parameters of the eclipsing binaries in the Large Magellanic cloud

홍경수,강영운,Hong, Kyeong Soo,Kang, Young Woon 한국천문학회 2012 天文學會報 Vol.37 No.2

We present photometric solutions of the 26,212 eclipsing binaries discovered in the LMC by Graczyk et al. (2011). They published that 70 percent of a total are detached systems. Another 25 and 5 percent are semi-detached and contact binaries, respectively. We discovered that 21 percent of 26,121 eclipsing binary stars are eccentric orbit systems. The binary star distribution in the LMC is different from those of the Galactic center direction (Bade window). It is very interesting that there are only 5 of 357 (2 percent) stars have eccentric orbit in the Galactic Center (Kang 2011). We selected the light curve of 18,274 detached systems. Then we estimated the fundamental parameters on the basis of their photometric solutions and the semi-major-axis (a) assuming the distance modulus to the LMC~18.50. We compared the estimated fundamental parameters with an empirical mass-luminosity relation and consistency between mass-radius relation base on stellar evolution model in the low metallicity (Z=0.008) by Bertelli et al. (2009). This method allows for independent determine of the fundamental parameters of the eclipsing binaries in the LMC without the radial velocity curves.

축산식품 중 벤지미다졸계 구충제 잔류실태 조사

이경진(Kyung Jin Lee),강영운(Young Woon Kang),강은귀(Eungui Kang),김미란(Miran Kim),반경녀(Kyeong Nyeo Bahn),장영미(Young Mi Jang),김미혜(Meehye Kim) 한국식품과학회 2010 한국식품과학회지 Vol.42 No.5

본 연구를 통하여 확립된 시험법은 고감도를 가지고 선택성이 뛰어난 LC/MS/MS를 이용하여 한번의 시료전처리와 분석을 통하여 축산식품 중 잔류하는 벤지미다졸계 구충제인 albendazole, fenbendazole, thiabendazole, flubendazole 및 oxibendazole 5종의 잔류량 분석을 가능하게 하였다. 추출용매로 ethyl acetate를 사용하고 MCX 카트리지를 이용하여 정제를 한 시험법으로 Codex guideline(20)에 따라 검량선의 직선성, 회수율, 검출한계 및 정량 한계 등에 대한 실효성을 검증한 결과 검량선은 모두 0.999 이상의 좋은 직선성을 가졌으며 회수율은 albendazole 71-74%, fenbendazole 70-72%, thiabendazole 79-83%, flubendazole 79-83%, oxibendazole 81-86%로 좋은 결과를 얻었다. 또한 검출한계 및 정량한계는 0.01 ppb, 0.03 ppb로 잔류허용기준이 가장 낮은 flubendazole의 10 ppb보다 100배 정도 더 좋은 감도를 가지고 있으며, 소의 근육, 간, 및 천엽에서 MSPD법으로 분석한 실험(21)과 정제 과정 없이 유기용매로 추출하여 LC/MS로 분석한 실험의 회수율 (22)보다 본 연구의 시험법이 더 좋은 회수율을 보여주었다. 또한 확립된 시험법을 이용하여 유통 중인 돼지고기, 쇠고기, 닭고기 총 270건을 수거하여 잔류량을 모니터링 한 결과 경기, 충청, 전라, 경상 지역에서 수거한 돼지고기에서 fenbendazole이 0.0012-0.0031 mg/kg의 수치로 검출이 되었고, 그 검출률은 4.4%이었으나 잔류허용기준인 0.1 mg/kg보다 낮은 수준이었다. 또한 fenbendazole에 대한 노출량 평가 결과 JECFA에서 정하고 있는 ADI의 0.01% 이하로 나타났다. 그러나 축산 농가에서 축산물의 생산량을 높이기 위하여 벤지미다졸계 구충제를 과다 사용하거나 안전휴약기간을 준수하지 않을 경우 축산물의 체내에 잔류가능성이 높기 때문에 지속적인 잔류실태 조사가 수행되어야 할 것으로 사료된다. This research investigated benzimidazole residues (albendazole, fenbendazole, flubendazole, thiabendazole, oxibendazole) in livestock products. A total of 270 samples of livestock products (beef, pork and chicken) were purchased from local markets in Korea. Ethyl acetate was used to extract analytes from the sample, after which ethyl acetate extracts were purified using a MCX cartridge. Analytes were detected using liquid chromatography-tandem mass spectrometry. The limit of detection was 0.01-0.04 ppb, the limit of quantification was 0.03-0.13 ppb, the linearity (r<SUP>2</SUP>) was 0.9992-1.0000, and the recovery was 70-85%. Residues of benzimidazoles, except for fenbendazole in pork, were not found in any of the 270 livestock samples. Fenbendazole was detected in the range of 1.2 to 3.1 ppb in 12 samples of pork.

환경유래 식품오염물질의 범부처 통합 저감화 플랫폼 설계

고아라(Ahra Ko),허지영(Ji-Young Heo),강영운(Young-Woon Kang*),강길진(Kil Jin Kang),정명섭(Myung-Sub Chung),이헌주(Hunjoo Lee) 한국환경보건학회 2017 한국환경보건학회지 Vol.43 No.4

Objectives: Chemicals derived from various environment media contaminates food across the food supply chain. In Korea, levels of contaminants in food have been sporadically measured by monitoring programs of different government agencies. There is difficulty with data compilation and integrated analysis across media. Therefore, the aim of this study was to propose an overall integrated database and analytical platform design for the ‘ECO-FOOD NET (Environmental COntaminant reduction platform for FOOD through an interagency collaboration NETwork)’, a tool to support the reduction of environmental contaminants in food. Methods: We developed a new data structure and standardized protocols for the compilation of integrated data. In addition, we conducted subject-oriented logical and physical relational database modeling and created the architecture design of the platform. Results: We established a standardized code system related to exposure media and route, analysis method and food matrix. In addition, we designed the seven software modules of ‘About the System’, ‘Introduction to Interagency Work’, ‘Media-Chemicals Profiles’, ‘Method Bank’, ‘Monitoring Data Base’, ‘Integrated Media Analysis’, and ‘Risk-Benefit Analysis’. Conclusions: This study will contribute to decision-making as a tool for executing risk management, such as sustainable reduction policies of contaminants in food.

천문 계산용 고성능 클러스터 구축

김종수,김봉규,임인성,백창현,남현웅,류동수,강영운,KIM JONGSOO,KIM BONG GYU,YIM IN SUNG,BAEK CHANG HYUN,NAM HYUN WOONG,RYU DONGSU,KANG YOUNG WOON 한국천문학회 2004 天文學論叢 Vol.19 No.1

A high performance computing cluster for astronomical computations has been built at Korea Astronomy Observatory. The 64 node cluster interconnected with Gigabit Ethernet is composed of 128 Intel Xeon processors, 160 GB memory, 6 TB global storage space, and an LTO (Linear Tape-Open) tape library. The cluster was installed and has been managed with the Open Source Cluster Application Resource (OSCAR) framework. Its performance for parallel computations was measured with a three-dimensional hydrodynamic code and showed quite a good scalability as the number of computational cells increases. The cluster has already been utilized for several computational research projects, some of which resulted in a few publications, even though its full operation time is less than one year. As a major resource of the $K^*Grid$ testbed, the cluster has been used for Grid computations, too.

곡류 중 알테나리아독소 시험법 밸리데이션

백옥진 ( Ock Jin Paek ),김형수 ( Hyung Soo Kim ),서정혁 ( Jung Hyuck Suh ),강영운 ( Young Woon Kang ),이준구 ( Joon Goo Lee ),봉영훈 ( Young Hoon Bong ),최훈 ( Hoon Choi ),곽지연 ( Ji Yeon Kwak ),이승일 ( Seung Il Lee ),박기훈 ( 한국환경농학회 2013 한국환경농학회 학술대회집 Vol.2013 No.-

Alternaria toxins haver been found to be natural food contaminants in grains, sunflowers seeds, and some visibly decayed fruits in many countries. Their natural occurrence in cereals has been reported in different countries. Several studies have reported the relevance of the this genus in crop. However, there are no studies on the method validation of alternaria toxin in cereals in our contry. A simple and sensitive analytical method based on HPLC with PDA and mobile phases using 0.1% phosphoric acid and acetonitrile was developed for simultaneous determination of alternaria toxins. A method validation for the determination of alternaria toxins in cereals was validated. In short, the method is as follows : A test portion of a sample is extracted with a mixture of methanol/water(90/10, v/v). This raw extract is then diluted, filtered, and applied to an SPE column. After washing and elution with acetonitrile, the elute is evaporated to dryness. After toxins in the dry residue in mobile phase are injected into a high performance liquid chromatography, and detected and quantified by PDA. For alternaria toxins in the cereals, Recovery test, calibration curves (Linearity), LOD and LOQ were successfully confirmed and Reproducibility relative standard deviations(RSDR) and Repeatability relative standard deviations(RSDr) for cereals samples were below 15% for the spiked cereals at 100 ug/kg. Since all these parameters lie well within the acceptable range set forth in EU mycotoxin method validation legislation. This method is The proposal method is sensitive, repeatable and rapid enough to apply to officially routine inspection of agricultural products including cereals.

채소류 중 수은 실태조사 및 위해평가

최훈 ( Hoon Choi ),김형수 ( Hyung Soo Kim ),서정혁 ( Jung Hyuck Suh ),백옥진 ( Ock Jin Paek ),강영운 ( Young Woon Kang ),이준구 ( Joon Goo Lee ),봉영훈 ( Young Hoon Bong ),곽지연 ( Ji Yeon Kwak ),이승일 ( Seung Il Lee ),신민홍 ( 한국환경농학회 2013 한국환경농학회 학술대회집 Vol.2013 No.-

This study was carried out to survey the levels of mercury in root vegetables and assess dietary exposure / risk to the Korean population health. Various samples including Panax ginseng C.A mayer, Codonopsis lanceolata, and Platycodon granditloum were collected from markets across Korea. The concentrations of mercury were measured using automatic mercury analyzer. The analytical and sampling methods in this study were full validated. The mercury content in root vegetables was determined below 100 μg/kg (maximum residue of mercury for salt established in Korea). For risk assessment, probable daily intake was calculated and compared with PTWI (tolerable weekly intake) established by JECFA. The level of overall exposure to mercury for Korean through root vegetables was below 1% of the recommended JECFA levels, indicating of little possibility of risk. Whereas, MFDS was conducted to assess the dietary exposure to mercury from food intake, based on several reports regarding mercury published by MFDS in the 2000s. The mean and 95th percentile for exposure to dietary mercury were 4.29 and 12.48 μg/day, corresponding to 13.6% and 39.7% of PTWI, respectively.