• 지구물리와물리탐사
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• 제6권2호
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• pp.87-94
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• 2003

지진 발생을 전후로 ULF대역 지자기장의 진폭이 증가하는 현상이 관측 보고 되고 있으며, 그 원인으로서 단층대 전기전도도의 빠른 변동이 거론되고 있다. 즉 단층대 매질에 유도전류가 발생하면 전자기장의 변동이 발생할 수 있다고 하는 것이다. 본 연구에서는 2차원 단층구조 모델에 대한 수치 계산을 통해 전자기장 교란의 발생 가능성을 살펴보았다. 전기전도도가 ULF 대역의 주파수로 진동하면 낮은 주파수의 전자기장들이 ULF 대역의 주파수로 변조되어 좁은 주파수 대역에 중첩됨으로써 상대적으로 큰 전자기장의 교란을 일으킬 가능성이 있다. 단층대의 전기전도도와 형태, 전기전도도 변동의 크기와 주파수, 지각 및 맨틀의 전기비저항 구조, 관측 전자기장 주파수 대역의 폭 등에 의해 전자기장 교란의 관측가능성이 결정됨을 확인할 수 있었다. 지진과 관련된 전자기적 활동의 관측을 위해서는 단층대의 구조 뿐만 아니라 심부 지각의 전기비저항 구조의 연구가 이루어져야 하며, 관측 주파수 대역의 적절한 선택이 필요하다.

• 한국광학회지
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• 제28권6호
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• pp.327-333
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• 2017

이 연구의 목적은 초등학교 6학년 '렌즈의 이용' 단원 학습에서 나타나는 모둠별 언어적 상호작용의 특성을 파악하는 것이다. 이 연구를 위해 초등학교 6학년 한 학급을 학업성취도에 따라 상, 중, 하 모둠으로 구성하고 6차시의 수업을 진행하였다. 학생들 사이의 상호작용을 분석하기 위해 모든 수업을 녹음하였으며, 전사된 자료는 언어적 상호작용 분석틀을 이용하여 분석하였다. 연구 결과, 상위 수준은 의견제시의 빈도가 높았으나, 과제완수를 위한 부정적인 언어적 상호작용이 많이 일어났다. 중 모둠은 다른 사람의 의견을 듣기 보다는 자신의 의견을 제시하는데 더 적극적이었다. 하 모둠은 의견제시가 많았음에도 불구하고, 동료의 의견을 존중하지 않거나 동료를 설득시키는 능력이 부족하여 결론 도출에 어려움을 겪었다. 따라서 모둠구성 시 간단한 탐구나 수용의 범위가 넓은 활동에서는 동질적인 모둠 구성이 좋으며, 과학적 개념 및 지식 이해를 위주로 하는 활동에서는 이질적인 모둠 구성이 더욱 효과적이라 할 수 있다.

• Journal of Hospice and Palliative Care
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• 제19권3호
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• pp.233-239
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• 2016

목적: 말기암환자 가족간병인의 사별가족 연구참여와 관련된 요인에 대해서는 알려진 바가 적다. 본 연구에서는 사별가족 연구에 실제 참여를 예측하는 임종 전 요인에 대해 살펴보고자 한다. 방법: 임종 전과 사별 후에 시행된 다기관 조사연구 자료를 이용하여, 전향적 관찰연구를 진행하였다. 사별가족 연구 참여와 관련된 요인을 추출하기 위해, 단계적 다변량 로지스틱 회귀분석을 이용하였다. 결과: 185명의 사별가족 중, 30명이 사후조사에 참여하였다(응답률: 16.2%). 사후조사 참여군과 비참여군은, 종교, 경제적 상태 그리고 임종 전 인지되었던 돌봄의 질에서 차이를 보였다. 최종 다변량 모델에 의하면, 종교를 가지고 있던 가족(adjusted odds ratio [aOR]=5.01, P=0.008), 높은 경제수준을 가진 가족(aOR=4.86, P=0.003) 그리고 가족 내 관계형성에 대한 돌봄에 만족했던 가족(aOR=4.49, P=0.003)이 그렇지 않은 가족에 비해 더 사후 연구에 참여를 하였다. 결론: 본 연구에 의하면, 임종기 돌봄의 질을 향상시키는 것은 사후 고통을 줄임으로써 사별가족연구에의 참여를 촉진시킨다. 사별가족 연구참여를 망설이는 사별가족들의 특성에 관심을 가질 필요가 있다.

• Pediatric Infection and Vaccine
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• 제26권3호
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• pp.140-147
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• 2019

목적: 피부 및 연조직 감염(skin and soft tissue infections [SSTIs])의 가장 흔한 원인은 황색포도알균(Staphylococcus aureus)이다. 본 연구는 19세 미만의 SSTI 환자에서 분리된 황색포도알균의 항생제 감수성의 변화추이를 알아보고자 하였다. 방법: 황색포도알균이 분리된 소아청소년 지역사회관련 SSTI 환자에서 후향적 관찰연구를 시행하였다. 미생물학 및 인구학적 자료를 수집하고, 항생제 감수성의 변화추이를 관찰하였다. 결과: 2010년 1월부터 2018년 12월까지 총 807개의 지역사회관련 황색포도알균이 연구에 포함되었다. Oxacillin에 대한 감수성은 전반적으로 증가하여(P<0.001) 2018년에는 75.0%였다. Trimethoprim/sulfamethoxazole과 tetracycline에 대한 감수성은 매우 높게 유지되어 2018년 각각 97.6%와 95.2%였다. 만 1-5세 연령군에서 만 6-18세 연령군에 비해 oxacillin 감수성이 유의하게 낮았다(53.4% vs. 75.0%, P<0.001). 결론: 소아청소년의 지역사회관련 SSTI의 원인이 된 황색포도알균 중 메티실린내성 황색포도알균의 비율이 감소하고 있는 것으로 보인다. 임상의는 경험적 항생제를 선택할 때 지역적 항생제 감수성 양상을 확인해야 한다.

• 천문학회지
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• 제37권1호
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• pp.41-53
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• 2004

It has been a big mystery what drives filament eruptions and flares. We have studied in detail an X1.8 flare and its associated filament eruption that occurred in NOAA Active Region 9236 on November 24,2000. For this work we have analyzed high temporal (about 1 minute) and spatial (about 1 arcsec) resolution images taken by Michelson Doppler Imager (MDI) onboard the Solar and Heliospheric Observatory, Hoc centerline and blue wing ($-0.6{\AA}$) images from Big Bear Solar Observatory, and 1600 ${\AA}$ UV images by the Transition Region and Corona Explorer (TRACE). We have found that there were several transient brightenings seen in H$\alpha$ and, more noticeably in TRACE 1600 ${\AA}$ images around the preflare phase. A closer look at the UV brightenings in 1600 ${\AA}$ images reveals that they took place near one end of the erupting filament, and are a kind of jets supplying mass into the transient loops seen in 1600 ${\AA}$. These brightenings were also associated with canceling magnetic features (CMFs) as seen in the MDI magnetograms. The flux variations of these CMFs suggest that the flux cancellation may have been driven by the emergence of the new flux. For this event, we have estimated the ejection speeds of the filament ranging from 10 to 160 km $s^{-1}$ for the first twenty minutes. It is noted that the initiation of the filament eruption (as defined by the rise speed less than 20 km $s^{-1}$) coincided with the preflare activity characterized by UV brightenings and CMFs. The speed of the associated LASCO CME can be well extrapolated from the observed filament speed and its direction is consistent with those of the disturbed UV loops associated with the preflare activity. Supposing the H$\alpha$/UV transient brightenings and the canceling magnetic features are due to magnetic reconnect ion in the low atmosphere, our results may be strong observational evidence supporting that the initiation of the filament eruption and the preflare phase of the associated flare may be physically related to low-atmosphere magnetic reconnection.

• 천문학회보
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• 제35권1호
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• pp.82-82
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• 2010

We measure the topology of the galaxy distribution using the Seventh Data Release of the Sloan Digital Sky Survey (SDSS DR7), examining the dependence of galaxy clustering topology on galaxy properties. The observational results are used to test galaxy formation models. A volume-limited sample defined by Mr<-20.19 enables us to measure the genus curve with amplitude of G=378 at 6h-1Mpc smoothing scale, with 4.8% uncertainty including all systematics and cosmic variance. The clustering topology over the smoothing length interval from 6 to 10h-1Mpc reveals a mild scale-dependence for the shift and void abundance (A_V) parameters of the genus curve. We find strong bias in the topology of galaxy clustering with respect to the predicted topology of the matter distribution, which is also scale-dependent. The luminosity dependence of galaxy clustering topology discovered by Park et al. (2005) is confirmed: the distribution of relatively brighter galaxies shows a greater prevalence of isolated clusters and more percolated voids. We find that galaxy clustering topology depends also on morphology and color. Even though early (late)-type galaxies show topology similar to that of red (blue) galaxies, the morphology dependence of topology is not identical to the color dependence. In particular, the void abundance parameter A_V depends on morphology more strongly than on color. We test five galaxy assignment schemes applied to cosmological N-body simulations to generate mock galaxies: the Halo-Galaxy one-to-one Correspondence (HGC) model, the Halo Occupation Distribution (HOD) model, and three implementations of Semi-Analytic Models (SAMs). None of the models reproduces all aspects of the observed clustering topology; the deviations vary from one model to another but include statistically significant discrepancies in the abundance of isolated voids or isolated clusters and the amplitude and overall shift of the genus curve. SAM predictions of the topology color-dependence are usually correct in sign but incorrect in magnitude.

• 천문학회보
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• 제42권1호
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• pp.40.1-40.1
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• 2017

The NISS (Near-infrared Imaging Spectrometer for Star formation history) is the near-infrared spectro-photometric instrument optimized to the Next Generation of small satellite series (NEXTSat). To achieve the major scientific objectives for the study of the cosmic star formation in local and distant universe, the spectro-photometric survey covering more than 100 square degree will be performed. The main observational targets will be nearby galaxies, galaxy clusters, star-forming regions and low background regions. The off-axis optics was developed to cover a wide field of view ($2deg.{\times}2deg.$) as well as the wide wavelength range from 0.95 to $2.5{\mu}m$, which were revised based upon the recent test and evaluation of the NISS instrument. The mechanical structure were tested under the launching condition as well as the space environment. The signal processing from infrared sensor and the communication with the satellite were evaluated after the integration into the satellite. The flight model of the NSS was 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. The accurate calibration data were obtained in our test facilities. Here, we report the test results of the flight model of the NISS.

• 천문학회보
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• 제43권1호
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• pp.41.1-41.1
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• 2018

We introduce a current status and future plans of Korea Microlensing Telescope Network (KMTNet) microlensing experiments, which include an observational strategy, pipeline, event-finder, and collaborations with Spitzer. The KMTNet experiments were initiated in 2015. From 2016, KMTNet observes 27 fields including 6 main fields and 21 subfields. In 2017, we have finished the DIA photometry for all 2016 and 2017 data. Thus, it is possible to do a real-time DIA photometry from 2018. The DIA photometric data is used for finding events from the KMTNet event-finder. The KMTNet event-finder has been improved relative to the previous version, which already found 857 events in 4 main fields of 2015. We have applied the improved version to all 2016 data. As a result, we find that 2597 events are found, and out of them, 265 are found in KMTNet-K2C9 overlapping fields. For increasing the detection efficiency of event-finder, we are working on filtering false events out by machine-learning method. In 2018, we plan to measure event detection efficiency of KMTNet by injecting fake events into the pipeline near the image level. Thanks to high-cadence observations, KMTNet found fruitful interesting events including exoplanets and brown dwarfs, which were not found by other groups. Masses of such exoplanets and brown dwarfs are measured from collaborations with Spitzer and other groups. Especially, KMTNet has been closely cooperating with Spitzer from 2015. Thus, KMTNet observes Spitzer fields. As a result, we could measure the microlens parallaxes for many events. Also, the automated KMTNet PySIS pipeline was developed before the 2017 Spitzer season and it played a very important role in selecting the Spitzer target. For the 2018 Spitzer season, we will improve the PySIS pipeline to obtain better photometric results.

• 천문학회보
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• 제43권1호
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• pp.64.1-64.1
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• 2018

SNe light curves have been used to understand the expansion history of the universe, and a lot of efforts have gone into understanding the overall shape of the radioactively powered light curve. However, we still have little direct observational evidence for the theorized SN progenitor systems. Recent studies suggest that the light curve of a supernova shortly after its explosion (< 1 day) contains valuable information about its progenitor system and can be used to set a limit on the progenitor size, R*. In order to catch the early light curve of SNe explosion and understand SNe progenitors, we are performing a ~8hr interval monitoring survey of nearby galaxies (d < 50 Mpc) with 1-m class telescopes around the world. Through this survey, we expect to catch the very early precursor emission as faint as R=21 mag (~0.1 Rsun for the progenitor). In this poster, we outline this project, and present a few scientific highlights, such as the early light curve of SN 2015F in NGC 2442.

• 기본간호학회지
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• 제7권2호
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• pp.208-221
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• 2000

The objective of this research was to compare the flushing effects using 1:1,000 diluted heparin or 0.9% normal saline in relation to needle gauge and frequency of IV medications. The comparative categories were clotting, duration of patency, and incidence of phlebitis. The design of research was a Nonequivalent Control group, Post test, Nonsynchrorized Design. The independent variable was 0.9% normal saline flushing the IV locks and the dependent variables were clotting, duration of patency, and incidence of phlebitis. Subjects were medical-surgical inpatients over 15 years old and with peripherally placed IVs who were hospitalized in a university medical center. Exclusion criteria included foreigners and those who were rejected for this research. The final sample for data analysis included 295 IV sites in 194 patients; 154 were in the saline group and 141 were in the heparin group. Subjects were assigned to have IV locks is flushed with 0.9% normal saline in the experimental group and to have IV lock flushed with 1:1,000 diluted heparin(100 units) in the control group. In order to increase reliability, the nurses who were assigned to the units involved in the study received an explanation on the standard method for locking an IV, recording method for observational data and criteria for the detection of phlebitis. Data were collected for a period of 2 weeks, from March 16, 2000 to March 29, 2000. Total duration of IV was defined the time of IV insertion to the time of discontinuation. Phlebitis was defined as the presence of the following : pain, swelling. erythema at the insertion site. Chi-square was used to determine the association between the degree of clotting, duration of patency, and incidence of phlebitis for the diluted heparin or the normal saline and needle gauge and frequency of IV medications. The results are summarized as follows : (a) There was difference in the degree of clotting between two groups($X^2=5.882$, p=.015). (b) There was no difference in the degree of duration of patency between two groups($X^2=2.439$, p=.295). (c) There was no difference in the incidence of phlebitis between two groups($X^2=0.190$, p=.663). (d) There was difference in the degree of clotting($X^2=6.209$, p=.013) and in the degree of duration of patency($X^2=6.978$, p=.031) according the needle guage between the two groups. (e) There was difference in the incidence of phlebitis($X^2=5.008$, p=.025) according to the frequencies of IV injection between two groups.