• The Bulletin of The Korean Astronomical Society
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• v.43 no.2
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• pp.34.1-34.1
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• 2018

We investigate the properties of bright galaxies with various morphological types in Abell 1139 and Abell 2589, using the pixel color-magnitude diagram (pCMD) analysis. The 32 bright member galaxies ($Mr{\leq}-21.3mag$) are deeply imaged in the g and r bands in our CFHT/MegaCam observations, as a part of the KASI-Yonsei Deep Imaging Survey of Clusters (KYDISC). We examine how the features of their pCMDs depend on galaxy morphology and infrared color. We find that the g - r color dispersion as a function of surface brightness (${\mu}r$) shows better performance in distinguishing galaxy morphology, than the mean g - r color does. The best set of parameters for galaxy classification appears to be a combination of the minimum color dispersion at ${\mu}r{\leq}21.2mag\;arcsec-2$ and the maximum color dispersion at $20.0{\leq}{\mu}r{\leq}21.0mag\;arcsec-2$: the latter reflects the complexity of stellar populations at the disk component in a typical spiral galaxy. Moreover, the color dispersion of an elliptical galaxy appears to be correlated with its WISE infrared color ([4.6]-[12]). This indicates that the complexity of stellar populations in an elliptical galaxy is related to its recent star formation activities. From this observational evidence, we infer that gas-rich minor mergers or gas interactions may have usually occurred during the recent growth of massive elliptical galaxies.

• Journal of Astronomy and Space Sciences
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• v.21 no.3
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• pp.191-200
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• 2004

The accuracy of CCD observations obtained at the Korean 1.8m telescope has been studied. Seventeen comparison stars in the vicinity of the cataclysmic variable BG CMi have been measured. The 'artificial' star has been used instead of the 'control' star, what made possible to increase accuracy estimates by a factor of 1.3-2.1 times for 'good' and 'cloudy' nights, respectively. The algorithm of iterative determination of accuracy and weights of few comparison stars contributing to the artificial star, has been presented. The accuracy estimates for 13-mag stars are around $0.^m002$ mag for exposure times of 30 sec.

• Journal of The Korean Astronomical Society
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• v.38 no.4
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• pp.429-435
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• 2005

We present BV CCD photometry for the open clusters Czernik 24 and Czernik 27. These clusters have never been studied before, and we provide, for the first time, the cluster parameters; reddening, distance, metallicity and age. Czernik 24 is an old open cluster with age $1.8{\pm}0.2Gyr$, metallicity $[Fe/H]=-0.41{\pm}0.15dex$, distance modulus $(m-M)_0=13.1{\pm}0.3mag$ ($d=4.1{\pm}0.5kpc$), and reddening $E(B-V)=0.54{\pm}0.12mag$. The parameters for Czernik 27 are estimated to be $age=0.63{\pm}0.07Gyr$, $[Fe/H]=-0.02{\pm}0.10dex$, $(m-M)_0=13.8{\pm}0.2mag$ ($d=5.8{\pm}0.5kpc$), and $E(B-V)=0.15{\pm}0.05mag$. The metallicity and distance values for Czernik 24 are consistent with the relation between the metallicity and the Galactocentric distance of other old open clusters. We find the metallicity gradient of 51 old open clusters including Czernik 24 to be ${\Delta}[Fe/H]/{\Delta}R_{gc}=-0.064 {\pm}0.009dex\;kpc^{-1}$.

• The Korean Journal of Nuclear Medicine
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• v.27 no.2
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• pp.285-292
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• 1993

Avidin과 biotin의 높은 결합력을 이용하여 종양 영상을 개선하는 방법이 많이 연구되고 있다. 본 실험에서는 이러한 목적으로 쓰기 위하여 적당한 $^{99m}Tc$ 표지 avidin을 제조하였다. Avidin을 표지하기 위하여 우선 $^{99m}Tc$과 안정한 킬레이트를 형성할 수 있는 benzoylmercaptoacetyltriglycine (Bz-MAG3)과 biocytin을 화학적으로 결합시킨 Bz-MAG3-biocytin을 합성하였다. 이 화합물을 Tc-99m으로 표지시켜 avidin 또는 streptavidin을 1:1로 섞어 줌으로서 Tc-99m으로 표지된 avidin과 streptavidin을 제조하였다. 이들의 생쥐 생체내 분포를 조사한 결과 avidin의 경우 높은 간(56.6%, 10min)과 신장(28.5%, 10min) 축적을 보였고 streptavidin의 경우 높은 신장 축적 (28.9%, 21hr)을 보였다. Avidin의 높은 정상 조직 축적을 줄이기 위하여 succinic acid를 결합시켜 등전점(pI)을 낮춘 다음 같은 실험을 하여 본 결과 신장 축적율은 pI가 $7.0{\sim}9.3,\;5.5{\sim}6.2,\;4.0{\sim}4.8$로 낮아졌을 경우 19.0%, 3.1%, 1.7%로 각각 떨어졌지만 간에의 축적은 pI 변화에 따른 상관성을 찾아 볼 수가 없었다. 체내 제거율을 측정하여 본 결과 pI를 변화시킨 avidin과 변화시키지 않은 avdin들은 반감기가 13.5에서 16.0시간 사이로 큰 차이점을 보이지 않았는데 streptavidin은 반감기 61.5시간 정도로 느리게 제거된다는 것을 알았다. 이 실험의 결과 1. Avidin을 $^{99m}Tc$-MAG3-biocytin으로 안정하게 표지할 수 있었고, 2. pI가 낮아진 avidin은 신장에의 축적율이 크게 감소되었으며, 3. $^{99m}Tc$으로 표지된 avidin과 streptavidin은 먼저 간으로 흡수된 후 대사된 다음 신장으로 배설된다는 사실을 알았다.

• Childhood Kidney Diseases
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• v.10 no.1
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• pp.33-39
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• 2006

Purpose : Neonatal hydronephrosis is diagnosed with an incidence of 4.5-7% of pregnancies. Recently, early detection of neonatal hydroneprosis with antenatal ultrasonography has be-come possible. But consensus about its management has not been reached, especially concerning surgical intervention. The purpose of this study is to analyze the natural course of neonatal hydronephrosis and to determine the guideline of surgical intervention and follow up study. Methods : Sixty nine hydronephrotic kidneys were confirmed from April 2001 to April 2005. All cases were rechecked by ultrasonography once at least and had a minimum follow-up of 6 months. We classified the patients into 4 groups according to the anterior posterior pelvic diameter(APPD) on perinatal ultrasonography. Ultrasonography to measure the APPD diameter and Society for Fetal Urology(SFU) grade, $^{99m}Tc-MAG3$ scan were done to a set protocol. Pyeloplasty was peformed according to the protocol. Results : Pyeloplasty was not needed in most cases where the APPD was below 10 mm and where the SFU grade were less than grade 3. Many cases with APPD 10 mm above or SFU grade III above had undergone pyeloplasty. We found a correlation between obstruction grade on MAG3 scan and whether surgery was performed or not. Conclusion : If APPD is above 10 mm, SFU grade is above grade 3 or urinary tract obstruction is suspected by MAG3 scan, pyeloplasty must be considered. In cases where APPD is below 10mm and SFU grade is less than grade 3, we can observe the natural course of neonatal hydronephrosis with consecutive follow-up. (J Korean Soc Pediatr Nephrol 2006;10:33-39)

• The Korean Journal of Nuclear Medicine Technology
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• v.17 no.2
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• pp.25-30
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• 2013

Purpose: To evaluate kidney function, renal relative uptake is very important and is affected by kidney and the setting of background region of interest (ROI). In particular, in the case of patients with hydronephrosis to the naked eyes, such as size, position and shape etc. can be difficult to identify. So according to ROI to be set by user, the results are many differences. This study assumes the ROI of a constant kidney. According to the change of background ROI by analyzing renal relative uptake affect how the results are intended to study. Materials and Methods: From January 2012 to February 2013, we analyzed 27 patients with hydronephrosis who were examined MAG3 test in nuclear medicine department of Samsung medical center. After patients were received intravenous injection of $^{99m}Tc-MAG3$ 185 MBq (5 mCi) data were obtained. While we reconstructed images of patients, we've changed background ROI in the process of setting up ROI. First, in the process of renal processing, automatic ROI which set automatically and background ROI which needed to set manually were compared. Second, we set the ROI position separated by above, lateral and bottom of kidney. Third, background setting time were compared with 1-2 min and 2-3 min. Results: The relative uptake occurred in 3.7%p of the errors on average in Automatic & Manual ROI study. And comparison of background ROI position study, located in the lower position was more accurate results. Above, lateral, bottom each of the values 74.6%, 67.6% and 62.0% showed respectively. The standard value was 59.9%. finally, split function range test doesn't show significant difference. Conclusion: The study shows that relative uptake of kidney is affected in the background ROI. Therefore, it should be set by considering various dependent factors.

• Journal of The Korean Astronomical Society
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• v.21 no.1
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• pp.57-65
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• 1988

The absolute measurements of fluxes in the region ${\lambda}{\lambda}3,100-8,090\;{\AA}$ emitted in the visible continua of some galactic Wolf-Rayet stars are presented. These observations were made by a two-channel scanner which was built up cooperatively by the Observatoire of Lyon and the Laboratoire d'Astronomie Spatiale. The fluxes, dereddened from those data, were combined with IUE and ANS ultraviolet measurements. These fluxes were compared with those of LTE plane paralleled model atmospheres of Kurucz (1979) and were also integrated in order to derive effective temperatures and bolometric corrections for the program stars. The derived effective temperatures and bolometric corrections for the stars were in the range of $25,000\;K{\sim}32,700\;K$, and of $-2.5\;mag.{\sim}-3.7\;mag.$, respectively.

• Journal of Sensor Science and Technology
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• v.5 no.4
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• pp.9-15
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• 1996

In order to display magnetic signals obtained from a magneto-resistance sensor, a direct current magnetometer was designed and its circuit was constructed. The magnetic fields measured by the home-made magnetometer, which showed good functions of automatic ranging, analog output, and vector sensing, were well agreed with those by commercial MAG-01 magnetometer. The measurement range of the magnetometer was $1\;{\mu}T$ to 1.999 mT, the resolution was -132 dB within 1 Hz bandwidth and the measured magnetic fields could be displayed with $3{\cdot}1/2$-digit LED.

• Journal of The Korean Radiological Technologist Association
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• v.29 no.1
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• pp.219-219
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• 2003

• Korean Journal of Food Science and Technology
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• v.36 no.2
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• pp.211-216
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• 2004

Mono-and diacylglycerol-enriched oil was produced from corn oil through enzymatic glycerolysis using 1,3-specific immobilized lipase in solvent-free system and stirred-tank batch reactor. HPLC analysis revealed enriched oil was respectively composed of: 45.05, 16.27, 23.05, and 14.98% triacylglycerol, 1,3-diacylglycerol, 1,2-diacylglycerol, and monoacylglycerol; 13.21, 0.15, 2.02, 34.36, 49.12, and 1.14 mol% palmitic, palmitoleic, stearic, oleic, linoleic, and linolenic acids; and 0.014, 0.029, 0.010 and 0.053% ${\alpha},\;{\gamma},\;{\delta}-$, and total tocopherols. Physiochemical and melting properties of enriched oil were evaluated. Oxidative stability study revealed enriched oil showed higher peroxide and p-anisidine values than corn oil. Rosemary extracts (100 to 300 ppm) reduce oxidation.