• 한국식품저장유통학회:학술대회논문집
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• 한국식품저장유통학회 2003년도 춘계총회 및 제22차 학술발표회
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• pp.119.1-119
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• 2003

단체 급식의 증가와 더불어 편의식품을 선호하는 소비 경향에 맞추어 최소가공한 과일의 갈변저해를 위한 저해제를 탐색하였다. 실험에 사용한 과일은 배와 감으로 각각 박피하여 속심을 제거한 후 배는 8조각으로 절단하고 감은 1~2cm 두께로 slice 하였다. 저해제는 1% ascorbic acid, citric acid, NaCl, MgCl$_2$, CaCl$_2$, oxalic acid, EDTA, raffinose, salicylic acit, sporix를 사용하였다. 또한 열수 추출한 오약, 계피, 황기, 당기, 건칡, 진피, 천궁, 감초 등도 저해제로 사용하였다. 최소가공한 과일은 저해제에 3분간 침지한 후 물기를 제거하고 tray에 포장하여 실온에서 저장하면서 colorimeter를 이용하여 갈변도의 변화를 측정하였다. 갈변 정도를 나타내는 $\Delta$E 는 시간의 경과에 따라 점차 감소하는 경향을 보였으나 배의 경우 변화 정도가 크지 않았다. NaCl, MgCl$_2$, CaCl$_2$를 처리한 배의 갈변 정도가 가장 적었다. cysteine을 처리한 구에서는 황화합물 냄새가 났다. 또한 oxalic acid를 처리한 구에서는 연화가 빠르게 일어났으며 저장 시간이 경과함에 따라 수분이 용출되었다. 한약재는 자체 색으로 인해 배의 색변화를 증가시켰으며 이취가 발생했다. 또한 저장 시간이 경과함에 따라 건조가 빠르게 일어나 관능적으로도 좋지 않은 결과를 나타냈다. 감에서는 CaCl$_2$, MgCl$_2$를 처리한 구에서 색의 변화가 가장 적었으며 cysteine은 색변화는 적었으나 배의 경우과 같이 이취가 발생하였다. 한약제는 계피와 진피를 처리한 감에서 색의 변화를 저해하는 효과를 보였다.를 처리하였을 경우 당귀, 천문동을 처리한 구에서 효과를 보였다. oxalic acid는 갈변저해에는 효과적이었으나 시간이 경과함에 따라 수분의 용출이 증가하였으며 물성의 변화도 컸다. 또한 ZnCl$_2$를 처리한 구에서는 이취 발생과 수분 용출이 컸으며 색의 변화도 컸다.내었다. 고온 단시간 처리구의 경우 저온 장시간 처리구와는 달리 저장 1일 후부터 그 농도가 다소 상승되었다가 다시 감소는 경향을 보였다. 한편 열처리하여 냉각시킨 직후 및 저장1주 후 사과의 pH, 산도, 당도, 경도, 과육의 갈변도 등을 조사하였던 바 대조구 및 처리구간에 일부 항목에 있어서는 약간의 차이를 나타내었다. 대치할 수 있을 것이라고 사료된다. 수분함량은 기계적 검사보다 관능검사와 더욱 높은 상관관계를 나타냈다.내었다. 항균활성이 우수한 생약재를 농도별로 활성을 조사한 결과, 물 추출물과 10% Ethanol 추출물 모두 낮은 농도에서도 우수한 항균활성을 나타내었다.취와 함께 점질성 갈변물질이 생성되었다. 이와 같은 결과로 볼 때, BAAG의 처리는 BAAC의 경우보다 가격은 저렴하면서도 항균력은 우수한 천연 항균복합제재로써 농산물 식품원료에 적용하여 선도유지 기간을 연장할 수 있는 효과를 기대할 수 있었다. 과일 등의 포장제로서 이용할 가능성을 확인하였다.로 [-wh] 겹의문사는 복수 의미를 지닐 수 없 다. 그러면 단수 의미는 어떻게 생성되는가\ulcorner 본 논문에서는 표면적 형태에도 불구하고 [-wh]의미의 겹의문사는 병렬적 관계의 합성어가 아니라 내부구조를 지니지 않은 단순한 단어(minimal $X^{0}$ elements)로 가정한다. 즉, [+wh] 의미의 겹의문사는 동일한 구성요 소를 지닌 병렬적 합성어([$[W1]_{XO-}$ $[W1]_{XO}$ ]

• 한국환경생태학회지
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• 제28권4호
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• pp.411-418
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• 2014

본 연구는 빛공해 및 환경요인이 박새의 새벽 울음 시간에 미치는 영향을 밝히는데 목적이 있다. 연구대상지는 빛공해지역은 원주시 상지대학교 캠퍼스를 자연지역은 치악산국립공원 서측 산림으로 선정하였다. 녹음기간은 2014년 3월 26일에서 5월 30일이었다. 빛공해에 따른 새벽 울음 시작 시간을 분석한 결과 빛공해지역이 자연지역보다 먼저 울음을 시작하는 경향이 뚜렷하였다(p<0.05). 박새는 주로 일출 전에 첫 울음을 시작하였는데, 대부분의 조사일에서 상지대학교의 박새가 먼저 울기 시작하였다. 이로 인해 암컷이 미성숙한 수컷과 교미할 확률이 높아지고, 적정 번식기보다 일찍 새끼가 부화함으로 해서 먹이자원이 부족할 가능성이 높을 것으로 판단되었다. 환경요인에 의한 영향은 일출시간, 시민박명, 항해박명, 천문박명, 평균온도, 최고온도, 최저온도, 월출시간, 운량과 박새의 새벽 울음소리와의 상관관계를 분석하였다. 야생조류 울음 시작시간은 월출시간과 운량을 제외한 모든 환경요인의 상관관계가 인정되었다. 박새는 일출시작 이전에 날이 밝아지기 시작하는 시민박명 전후에 첫 울음을 시작하였고, 일출시간과 대기 온도가 상승함에 따라 새벽 울음 시작시간도 앞당겨졌다. 월출시간과 운량은 상관관계가 인정되지 않았는데 이에 대해서는 추가적인 연구가 필요하다.

• 천문학논총
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• 제30권3호
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• pp.821-832
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• 2015

NGC 1039 영역의 변광성 탐사로부터 7개의 ${\delta}$ Scuti형 변광성, 2개의 ${\gamma}$ Doradus형 변광성, 14개의 식쌍성 및 5개의 장지기형 불규칙 변광성을 찾았다. 이 중에서 3개를 제외한 나머지는 모두 새로 발견한 것이다. 이들 중 ${\delta}$ Scuti형 변광성 4개와 ${\gamma}$ Doradus형 변광성 2개 및 장주기형 불규칙 변광성 1개는 성단구성원일 가능성이 크다. 14개의 식쌍성 중에서 12개는 주기와 변광진폭 등을 구하였으며, 나머지 2개는 22일 관측 자료 중 하루치에서만 식 현상이 나타나서 EA형 식쌍성으로 보인다. B, V등급의 변광진폭을 같이 구한 식쌍성의 변광진폭비 $A_V/A_B$는 0.92이며, ${\delta}$ Scuti형 변광성의 결과를 이용한 0.75와 뚜렷이 구분된다. 5개의 장주기형 불규칙 변광성은 하나를 제외하고 나머지는 주기가 너무 길었고, 또한 주기성인지 알 수 없어서 밝기 변화만으로 변광성임을 알 수 있었다. 이 연구에서 찾은 변광성은 V등급이 10.84등급부터 16.30등급까지 분포하며, V등급의 변광진폭이 0.5등급 이상이면 16.3등급까지도 변광 여부를 확인할 수 있었다.

• 천문학논총
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• 제30권1호
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• pp.11-16
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• 2015

First light galaxies have predictable linear clustering, and are expected to produce fluctuations with a characteristic spatial power spectrum, which peaks at an angular scale of ~ 10 arcminutes and in the $1-2{\mu}m$ spectral regions. The Cosmic Infrared Background ExpeRiment 2 (CIBER2) is a dedicated sounding rocket mission for measuring the fluctuations in the extragalactic infrared background light, following up the previous successful measurements of CIBER1. With a 28.5 cm telescope accompanied with three arms of camera barrels and a dual broadband filter on each H2RG (${\lambda}_c=2.5{\mu}m$) array, CIBER2 can measure 6 bands of wide field ($1.1{\times}2.2$ degrees) up to 3 AB magnitudes deeper than CIBER1. This project is leaded by California Institute of Technology/Jet Propulsion Laboratory, collaborating internationally with Institute of Space and Astronautical Science in Japan, Korea Astronomy and Space Science Institute, Korea Basic Science Institute, and Seoul National University. The Korean team is in charge of 1) one H2RG scientific array, 2) ground station hardware and software, 3) telescope lenses, and 4) flight and test bed electronics fabrication. In this paper, we describe the detailed activities of the Korean participation as well as the current status of the CIBER2 project.

• 천문학회보
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• 제39권2호
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• pp.102-102
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• 2014

The NISS (Near-infrared Imaging Spectrometer for Star formation history) onboard NEXTSat-1 is the near-infrared instrument onboard NEXTSat-1 which is being developed by KASI. The main scientific targets are nearby galaxies, galaxy clusters, star-forming regions and low background regions in order to study the cosmic star formation history in local and distant universe. After the Preliminary Design Review, we have fixed major specifications of the NISS. The off-axis optical design with 15cm apertureis optimized to obtain a wide field of view ($2deg.{\times}2deg.$), while minimizing the sensitivity loss. The opto-mechanical structure of the NISS was designed to be safe enough to endure in the launching condition as well as the space environment. The tolerance analysis was performed to cover the wide wavelength range from 0.95 to $3.8{\mu}m$ and to reduce the degradation of optical performance due to thermal variation at the target temperature, 200K. The $1k{\times}1k$ infrared sensor is operated in the dewar at 80K stage. We confirmed that the NISS can be cooled down to below 200K in the nominal orbit through a radiative cooling. Here, we report the preliminary design of the NISS.

• 천문학회보
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• 제41권2호
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• pp.64.3-65
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• 2016

The NISS (Near-infrared Imaging Spectrometer for Star formation history) is the near-infrared instrument optimized to the Next Generation of small satellite series (NEXTSat). The capability of both imaging and low spectral resolution spectroscopy in the near-infrared range is a unique function of the NISS. The major scientific mission is to study the cosmic star formation history in local and distant universe. For those purposes, the main observational targets are nearby galaxies, galaxy clusters, star-forming regions and low background regions. The off-axis optical design is optimized to have a wide field of view ($2deg.{\times}2deg.$) as well as the wide wavelength range from 0.95 to $3.8{\mu}m$. Two linear variable filters are used to realize the imaging spectroscopy with the spectral resolution of ~20. The mechanical structure is considered to endure the launching condition as well as the space environment. The compact dewar is confirmed to operate the infrared detector as well as filters at 80K stage. The electronics is tested to obtain and process the signal from infrared sensor and to communicate with the satellite. After the test and calibration of the engineering qualification model (EQM), the flight model of the NSS is assembled and integrated into the satellite. To verify operations of the satellite in space, the space environment tests such as the vibration, shock and thermal-vacuum test were performed. Here, we report the test results of the flight model of the NISS.

• 천문학회보
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• 제41권2호
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• pp.42.1-42.1
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• 2016

The formation process and the dynamical properties of a large-scale quasi-circular flare ribbon were investigated using the SDO AIA and HMI data along with data from RHESSI and SOT. Within one hour time interval, two subsequent M-class flares were detected from the NOAA 12371 that had a ${\beta}{\gamma}{\delta}$ configuration with one bipolar sunspot group in the east and one unipolar spot in the west embedded in a decayed magnetic field. Earlier M2.0 flare was associated with a coronal loop eruption, and a two-ribbon structure formed within the bipolar sunspot group. On the other hand, the later M2.6 flare was associated with a halo CME, and a quasi-circular ribbon developed encircling the full active region. The observed quasi-circular ribbon was strikingly large in size spanning 650" in north-south and 500" in east-west direction. It showed the well-known sequential brightening in the clockwise direction during the decay phase of the M2.6 flare at the estimated speed of 160.7 km s-1. The quasi-circular ribbon also showed the radial expansion, especially in the southern part. Interestingly, at the time of the later M2.6 flare, the third flare ribbon parallel to the early two-ribbon structure also developed near the unipolar sunspot, then showed a typical separation in pair with the eastern most ribbon of the early two ribbons. The potential field reconstruction based on the PFSS model showed a fan shaped magnetic configuration including fan-like field lines stemming from the unipolar spot and fanning out toward the background decayed field. This large-scale fan-like field overarched full active region, and the footpoints of fan-like field lines were co-spatial with the observed quasi-circular ribbon. From the NLFF magnetic field reconstruction, we confirmed the existence of a twisted flux rope structure in the bipolar spot group before the first M2.0 flare. Hard X-ray emission signatures were detected at the site of twisted flux rope during the pre-flare phase of the M2.0 flare. Based on the analysis of both two-ribbon structure and quasi-circular ribbon, we suggest that a tether-cutting reconnection between sheared arcade overarching the twisted flux rope embedded in a fan-like magnetic field may have triggered the first M2.0 flare, then secondary M2.6 flare was introduced by the fan-spine reconnection because of the interaction between the expanding field and the nearby quasi-null and formed the observed large-scale quasi-circular flare ribbon.

• 천문학회보
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• 제41권2호
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• pp.44.1-44.1
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• 2016

The Sagittarius-Carina spiral arm in the Galaxy contains several massive young open clusters. We present a deep optical photometric study on the massive young open clusters in the Sagittarius-Carina arm, Westerlund 2 and the young open clusters in the ${\eta}$ Carina nebula. Westerlund 2 is a less studied starburst-type cluster in the Galaxy. An abnormal reddening law for the intracluster medium of the young starburst-type cluster Westerlund 2 is determined to be $R_{V,cl}=4.14{\pm}0.08$. The distance modulus is determined from zero-age main-sequence fitting to the reddening-corrected color-magnitude diagrams of the early-type members to be $V_0-M_V=13.9{\pm}0.14mag$. The pre-main sequence (PMS) members of Westerlund 2 are selected by identifying the optical counterparts of X-ray emission sources from the Chandra X-ray observation and mid-infrared emission sources from the Spitzer/IRAC (the Infrared Array Camera) observation. The initial mass function (IMF) shows a slightly flat slope of ${\Gamma}=-1.1{\pm}0.1$ down to $5M_{\odot}$. The age of Westerlund 2 is estimated to be. 1.5 Myr from the main-sequence turn-on luminosity and the age distribution of PMS stars. The ${\eta}$ Carina nebula is the best laboratory for the investigation of the Galactic massive stars and low-mass star formation under the influence of numerous massive stars. We have performed deep wide-field CCD photometry of stars in the ${\eta}$ Carina nebula to determine the reddening law, distance, and the IMF of the clusters in the nebula. We present VRI and $H{\alpha}$ photometry of 130,571 stars from the images obtained with the 4m telescope at Cerro Tololo Inter-American Observatory (CTIO). RV,cl in the η Carina nebula gradually decreases from the southern part (~4.5, around Trumpler 14 and Trumpler 16) to the northern part around Trumpler 15 (~3.5). Distance to the young open clusters in the ${\eta}$ Carina nebula is partly revised based on the zero-age main-sequence fitting to the reddening-corrected color-magnitude diagrams (CMDs) and the (semi-) reddening-independent CMDs. We select the PMS members and candidates by identifying the optical counterparts of X-ray sources from the Chandra Carina Complex Survey and mid-infrared excess emission stars from the Spitzer Vela-Carina survey. From the evolutionary stage of massive stars and PMS stars, we obtain that the northern young open cluster Trumpler 15 is distinctively older than the southern young open clusters, Trumpler 14 (${\leq}2.5 Myr$) and Trumpler 16 (2.5-3.5 Myr). The slopes of the IMF of Trumpler 14, Trumpler 15, and Trumpler 16 are determined to be $-1.2{\pm}0.1$, $-1.5{\pm}0.3$, and $-1.1{\pm}0.1$, respectively. Based on the RV,cl of several young open clusters determined in this work and the previous studies of our group, We suggest that higher RV,cl values are commonly found for very young open clusters with the age of < 4 Myr. We also confirm the correlation between the slope of the IMF and the surface mass density of massive stars.

• 천문학회보
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• 제41권2호
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• pp.33.1-33.1
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• 2016

We report detection of short-term flux variability in multi-epoch observations and intraday variability in polarized emission at millimeter-wavelength from S5 0716+714 using Korean VLBI Network (KVN) radio telescopes. Over the whole observation epochs, the source shows significant inter-month variations at K- and Q-band with modulation indices of 19% at K-band and 36% at Q-band. In each epoch, the source shows monotonic flux increase in Epoch 1 and 3, and monotonic flux decrease in Epoch 2 and 4. We found an inverted spectrum with mean spectral indices of -0.57 in Epoch 1 and -0.15 in Epoch. On the contrary, we found relatively steep indices of 0.24 and 0.17 in Epoch 2 and Epoch 4, respectively. In the study of intraday variability of polarization, we found significant variations in the degree of linear polarization at 86 GHz, and in polarization angle at 43 and 86 GHz during ~10 h. The spectrum of the source is quite flat with spectral indices of -0.07 to 0.07 at 22-43 GHz and -0.23 to 0.04 at 43-86 GHz. The measured degree of the linear polarization ranges from 2.3% to 3.3 % at 22 GHz, from 0.9% to 2.2 % at 43 GHz and from 0.4 % to 4.0 % at 86 GHz, yielding prominent variations at 86 GHz over 4-5 h. The linear polarization angle is in the range of 4 to $12^{\circ}$ at 22 GHz, -39 to $81^{\circ}$ at 43 GHz, and 66 to 119 at 86 GHz with a maximum rotation of $110^{\circ}$ at 43 GHz over ~4 h. We estimated the Faraday rotation measures (RM) ranging from -9200 to 6300 rad m-2 between 22 and 43 GHz, and from -71000 to 7300 rad m-2 between 43 and 86 GHz, respectively. The frequency dependency of RM was investigated, yielding a mean power-law index, a, of 2.0. This implies that the polarized emission from S5 0716+714 at 22-86 GHz moves through a Faraday screen in or near the jet of the source.

• 천문학회지
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• 제51권3호
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• pp.49-63
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• 2018

We carry out a study of Sub-Millimeter Galaxies (SMGs) in the AKARI NEP-Deep field using the James Clerk Maxwell Telescope (JCMT) SCUBA-2 $850{\mu}m$ source catalog, released as part of the SCUBA-2 Cosmology Legacy Survey (S2CLS) program. The SCUBA-2 $850{\mu}m$ map has a root mean square (rms) noise of $1.2mJy\;beam^{-1}$ and covers an area of $0.60degree^2$. We find four SMGs which have counterparts to Herschel sources with spectroscopic redshifts in the literature. In addition, three dust obscured galaxies (DOGs) detected in Herschel bands are selected as a comparison sample. We derive IR luminosities of SMGs using the CIGALE code, which are similar to those of high redshift SMGs from previous studies. The contribution of AGN to the total IR luminosity in SMGs (2%-11%) is smaller than the lower limit for the one in DOGs (19%-35%), which is consistent with the expectation from the evolutionary scenario of massive galaxies. We search for SMGs in overdense regions as protocluster candidates and investigate four regions, including candidates around three DOGs. Finally, we argue that follow-up spectroscopic observation for the NEP-Deep field will provide crucial information to understand the role of SMGs in the evolution of massive galaxies.