• 천문학회보
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• 제36권2호
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• pp.83.1-83.1
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• 2011

Solar flares are very spectacular, and are associated with various phenomena. Coronal shocks or disturbances are one of such flare-related phenomena. Although Moreton waves and X-ray waves are well explained with MHD first mode shocks propagating in the corona, there still remains a big problem on the nature of the waves, since they are very rare phenomena. On the other hand, EIT waves (or EUV waves) have been paid attention to as another phenomenon of coronal disturbances. However, the physical features (velocity, opening angle, and so on) are much different from those for Moreton waves and X-ray waves. We report detailed features of the coronal disturbances associated with the 2010 February 7 and the 2010 August 18 flares. For the former flare we analyzed the H-alpha images obtained by SMART at Hida Observatory, Kyoto University, Japan and by a flare telescope at National Astronomical Observatory of Japan, the X-rays images taken by Hinode/XRT, and the EUV images obtained by the both satellites of STEREO, and found the Moreton wave, X-ray wave, and EIT wave, simultaneously. In the latter flare, on the other hand, we observed a very fast EUV wave in EUV images taken by SDO/AIA. The propagating speed is comparable to the MHD first mode wave, while there is no obvious evidence of shocks for this flare. From these results, we discuss the nature of coronal disturbances.

• 아태비즈니스연구
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• 제11권4호
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• pp.243-254
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• 2020

Purpose - This paper explores whether overnight returns measured from the last closing price to today's opening price explain the cross-section of stock returns. Design/methodology/approach - This study is conducted using the Korean stock market data from 1998 to 2018, obtained from DataGuide database. The analysis begins with portfolio-level tests, followed by firm-level cross-sectional regressions. Findings - First, when decile portfolios sorted on the daily average of overnight returns in the previous months, the highest decile portfolio exhibits a significant negative risk-adjusted return. This suggests that stocks with higher average overnight returns are temporarily overvalued due to buying pressure from investors. Second, at least 6 months of persistence exists in average overnight returns, which is in line with the results reported by Barber, Odean and Zhu (2009) that investor sentiment persists over several weeks. Finally, Fama-MacBeth cross-sectional regression of expected returns after controlling for a variety of firm characteristic variables such as firm size, book-to-market ratio, market beta, momentum, liquidity, short-term reversal, the slope coefficient for overnight returns remains negative and statistically significant. Research implications or Originality - Overall, the evidence consistently suggests that overnight return is considered as a new priced factor in the cross-section of expected returns. The findings of this paper not only adds to finance literature, but also could be useful to practitioners in making stock investment decision.

• Korea Journal of Cosmetic Science
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• 제1권1호
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• pp.11-18
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• 2019

Caffeine is widely used in cosmetics and hair care products. Although its efficacy in stimulating hair growth has been confirmed in recent studies, its mechanism of action remains unelucidated. The present study aimed to determine the effects of caffeine on hair growth, with a focus on intracellular hair follicle activity. Experiments included in vitro and ex vivo tests, and a clinical study. Caffeine enhanced the cellular activity and potassium channel opening. It also promoted human hair follicle elongation. Immunohistochemical staining showed that the Ki-67 signal was significantly higher in cells treated with caffeine. These efficacies of caffeine were comprehensively demonstrated in clinical results, wherein caffeine-containing shampoo improved hair density after 24 weeks of testing. Collectively, the results of this study demonstrated that caffeine promoted hair growth and inhibited the progression of hair loss by enhancing intracellular activity of hair follicles.

• Geomechanics and Engineering
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• 제24권6호
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• pp.505-518
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• 2021

The present paper has been carried out to understand the effects of impact loading on the rock tunnels, constructed in different region corresponding to varying unconfined compressive strength (UCS), through finite element method. The UCS of rockmass has substantial role in the stability of rock tunnels under impact loading condition due to falling rocks or other objects. In the present study, Dolomite, Shale, Sandstone, Granite, Basalt, and Quartzite rocks have been taken into consideration for understanding of the effect of UCS that vary from 2.85 MPa to 207.03 MPa. The Mohr-Coulomb constitutive model has been considered in the present study for the nonlinear elastoplastic analysis for all the rocks surrounding the tunnel opening. The geometry and boundary conditions of the model remains constant throughout the analysis and missile has 100 kg of weight. The general hard contact has been assigned to incorporate the interaction between different parts of the model. The present study focuses on studying the deformations in the rock tunnel caused by impacting load due to missile for tunnels having different concrete grade, and steel grade. The broader range of rock strength depicts the strong relationship between the UCS of rock and the extent of damage produced under different impact loading conditions. The energy released during an impact loading simulation shows the variation of safety and serviceability of the rock tunnel.

• 건축역사연구
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• 제31권3호
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• pp.31-40
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• 2022

In the historical city center where overall development has not been made, it is not difficult to observe the asp ect of the urban change process over time accumulated. Seochon(西村), which collectively refers to 13 legal dong s in the west of Gyeongbokgung Palace, is also considered a representative historical village with high value as a historical and cultural cityscape because of historical context remains throughout the lot. Therefore, research ex amining the process of changing parcels in this area is useful for a more three-dimensional understanding of the presence of several layers of time. In this study, relationship between the opening time of each road, the river co ver process, and the current building establishment process is examined using maps after the pre-modern period and modern era. In addition, to examine the specific change process of individual lots using the old land register, building management ledger and cadastral map.

• 한국도서관정보학회지
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• 제46권3호
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• pp.349-379
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• 2015

1980년대에 79개관에 불과했던 전국 공공도서관이 2013년 말 기준으로 885개관에 이르고 있다. 특히 2000년대 이후에 건립된 도서관이 전체 도서관의 60%를 넘어서고 있을 정도로 도서관의 시대가 도래 하면서 상당한 양적팽창이 이루어지고 있다. 그에 따른 질적 측면도 중요하게 부각되면서 공공도서관의 효율적 공간구성에 대한 이용자 요구가 증대되고 있다. 특히 이용자의 요구에 부응하기 위한 디지털열람실과 문화교육실의 증가는 2000년 전 후의 변화에 따른 시사점으로 나타나고 있으며, 기존 공간구성 비율에서 벗어나 시대에 적합한 도서관 공간계획이 필요한 시점이다. 이 연구는 1980~1990년대 준공된 공공도서관과 2000년 이후 설립된 공공도서관을 중심으로 시대별 공공도서관의 공간구성 형태를 상호 비교분석하였다. 장서보존과 열람 기능이 강조되었던 1980~1990년대와 이용자의 측면을 고려하여 문화영역 기능이 확대된 2000년대 이후 공공도서관의 소요시설별 면적비율의 차이를 살펴봄으로써 현시점의 도서관 공간의 중요 고려요소를 도출할 수 있었다. 이는 시대요구와 부합할 수 있는 면적기준을 제시하기 위한 최종연구에 대해 기초자료를 제공한다는 점에서 그 의미가 크다.

• 지구물리와물리탐사
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• 제6권1호
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• pp.40-52
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• 2003

한반도와 일본열도 사이에 위치하는 동해 남서부의 열림모델이 다양하게 제시되었음에도 불구하고 한반도의 대륙주변부의 지각구조는 잘 알려져 있지 않다. 그 결과 동해의 열림을 설명하는 데에 필요한 대륙의 리프팅과 해저면 확장과정은 정확히 제시되지 못하고 있다. 이 연구에서는 다중채널 탄성파자료와 해저면지진계자료로부터 한반도의 대륙주변부에서 울릉분지의 중앙부까지 지각구조를 구하였다. 울릉분지의 지각은 그 두께가 약 10km로서 정상보다 두꺼우나 깊이에 따른 속도분포에서 전형적인 해양지각의 특성을 갖는다. 대륙주변부에서 대륙과 해양지각간의 급격한 전이가 발생하는데 약 50km의 거리에서 지각의 두께가 상당히 감소하며 모호면이 얕아진다. 대륙주변부에서는 특징적으로 고속도(최대 7.4km/s)의 하부지각이 존재하는데 이것은 대륙사면 아래에서 10km이상 두꺼우며 바다쪽으로 첨멸된다. 이 고속도의 하부지각은 맨틀의 온도가 정상보다 뜨거운 환경에서 대륙이 리프트되는 동안 형성된 magmatic underplating으로 해석된다. 대륙사면의 음향기반은 많은 양의 화산분출에 의해 발달된 화성층서를 보여준다. 이러한 점들은 한반도 대륙주변부의 진화가 화산성의 리프트된 대륙주변부에서 일어나는 과정에 의해 설명될 수 있음을 제시한다. 지구규모의 지진파 토모그래피는 상부 맨틀이 한반도의 대륙주변부와 울릉분지에서 비정상적으로 뜨거운 것을 보여줌으로써 이러한 제시를 뒷받침한다.

• Archives of Plastic Surgery
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• 제38권1호
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• pp.73-76
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• 2011

Purpose: Congenital midline upper lip sinus is a rare lesion. There are two postulates that can account for the formation of the upper lip sinus based on two major theories of the development of the face: the fusion theory and the merging theory. However, congenital midline lower lip sinus is very rarely reported and described. We report a case of a congenital midline sinus of the lower lip in a 6-year-old female. Methods: A 6-year-old girl presented with a nipple like swelling on the midline lower lip. Physical examination revealed about $5{\times}5$ mm protruding round mass with a just small opening that was non-tender to palpation. The mass was not associated with any skin changes. It umbilicated at the apex and contains a fistulous tract, discharging clear fluid. Only, simple radiologic finding shows bony spur on the lower one third of mandibular symphsis. Results: A small transverse ellipse is made around the opening and elevated mass with sharpe dissection. The tract is excised using the probe and dye as the guide. The tract was extended to periosteum of the lower one third of the mandible. The tract and involved periosteum were excised en bloc, and removed protrusion of the mandibular bone using diamond burr. Microscopic examination of the resected sinus revealed the fistulous tract itself, consisting of fibrous connective tissue covered with cornified stratified squamous epithelium, was observed in the center of the sample. In 6 months follow-up, This patient had a good result was obtained by the method of fistulectomy alone. Conclusion: Midline cranoifacial fistulas represent rare lesions resulting from abnormal fusion of embryologic structures. Our case report describes the excision of a congenital midline sinus of the lower lip in a 6-year-old female. This case represents the first report of a lower lip sinus presenting in a girl as a mass in the skin of the chin with extension to the midline of the mandible. However, the etiology of this rare congenital sinus remains obscure.

• 한국전통조경학회지
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• 제32권4호
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• pp.120-131
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• 2014

조선 개국 시 영조된 사직단은 일제강점기를 거치면서 사직공원으로 고착화되었고, 최근 복원에 대한 노력이 진행되고 있다. 통시적으로 분석된 사직단의 변화 내용은 다음과 같다. 첫째, 한 나라의 중요 국가제사를 지내던 장소로의 입지를 확보하고 강화되었던 조선시대 태조에서 일제강점기 이전까지의 시기이다. 태조대에 인왕산 자락에 축조했으며 임진왜란 시 소실된 후 영조 대에 제례시설이 완비되었다. 그러나 1908년 일제의 간섭이본격화되자 공간 멸실과 제사가 폐지되었다. 둘째, 일제에 의해 공원화가 진행되어 고착화된 1910년부터 1944년까지이다. 공원 관련 시설과 경계부에 이질적인 건축물이 들어섰고, 단 영역 재실 사직단문이 고적과 보물로 지정되기도 하였다. 셋째, 해방 이후 1984년까지 이질적 성격의 동상과 기념비, 건축물이 축조되어 혼재된 장소성을 지니게 된 시기이다. 사직터널의 개설로 사직단 문이 2번에 걸쳐서 이축되기도 하였다. 넷째, 사직단의 역사성과 상징성을 회복하기 위한 노력이 진행되고 있는 1985년부터 현재까지이다. 사직단 권역의 복원 계획이 진행되고 있으나 주민에 대한 반발로 난항을 겪고 있는 시기이기도 하다. 향후, 사직단의 원형 회복을 위한 복원을 위해서는 발굴조사를 통한 면밀한 고증과 주민의 이해가 함께 진행되어야 한다.

• Journal of Korean Neurosurgical Society
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• 제30권3호
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• pp.295-306
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• 2001

Objectives : The management of massive brain swelling remains an unsolved problem in neurosurgical field. Despite newly developed medical and pharmacological therapy, the mortality and morbidity due to massive brain swelling remains high. According to many recent reports, surgical decompression with dura expansion is superior to medical management in patients with massive brain swelling. We performed surgical treatment on the first line of treatment, and followed medical management in case with refractory increased intracranial pressure(ICP). To show the quantitative effect of decompressive surgery on the intracranial pressure, we performed ventricular puncture and checked the ventricular ICP continuously during the decompressive surgery and postoperative period. Materials and Methods : Fifty-one patients with massive brain swelling, undergoing bilateral decompressive craniectomy with dura expansion, were studied in this study. In all patients, ventricular puncture was performed at Kocher's point on the opposite side of massive brain swelling. The ventricular pressure was monitored continuously, during the bilateral decompression procedures and postoperative period. Results : The initial ventricular ICP were varied from 13mmHg to 112mmHg. Immediately after the bilateral craniectomy, mean ventricular ICP decreased to $53.1{\pm}15.8%$ of the initial ICP(ranges from 5mmHg to 87mmHg). Dura opening decreased mean ICP by additional 36.7% and made the ventricular pressure $16.4{\pm}10.5%$ of the initial pressure (ranges from 0mmHg to 28mmHg). Postoperatively, ventricular pressure was lowered to $20.2{\pm}22.6%$(ranged from 0mmHg to 62.3mmHg) of the initial ICP. The ventricular ICP value during the first 24 hours after decompressive surgery was found to be an important prognostic factor. If ICP was over 35mmHg, the mortality was 100% instead of additional medical(barbiturate coma therapy and hypothermia) treatments. Conclusion : Bilateral decompression with dura expansion is considered an effective therapeutic modality in ICP control. To obtain favorable clinical outcome in patients with massive brain swelling, early decision making on surgical management and proper patient selection are mandatory.