대가야 고아동 고분벽화 제작기술에 관한 연구

이화수,이한형,이경민,한경순,Lee, Hwa Soo,Lee, Han Hyeong,Lee, Kyeong Min,Han, Kyeong Soon 한국문화재보존과학회 2014 보존과학회지 Vol.30 No.4

고대 대가야시대(6세기) 고분벽화에 사용된 제작기술을 연구하기 위해 벽화 구조와 재질에 대한 정밀분석을 실시하였다. 벽화는 석실을 축조 후 벽면과 천정에 모르타르를 바르고 그 위에 바탕칠층을 조성하여 채색하였다. 천장을 제외한 사면의 벽면에는 모르타르 위로 대부분 진흙이 덧발려져 있다. 모르타르는 모래는 사용되지 않았고, 순수한 칼슘성분의 물질들로 이루어져 있다. 또한 소성(燒成)이 완전히 진행되지 않은 불규칙한 크기의 패각들이 혼합되어 있으며, 모르타르의 석회질은 굴 껍질을 소성하여 얻어진 것으로 추정되었다. 바탕칠층은 백토(kaolinite($Al_2Si_2O_5(OH)_4$) 또는 halloysite($Al_2Si_2O_5(OH)_4{\cdot}2H2_O$))를 사용하였으며, 채색에 사용된 적색안료는 진사(cinnabar(HgS) 또는 vermilion), 녹색은 공작석(malachite($Cu_2CO_3(OH)_2$)) 그리고 백색은 연백(lead white($PbCO_3{\cdot}Pb(OH)_2$))이 쓰인 것으로 나타났다. 모르타르 위로 조성된 토양층은 주로 중립사 이하 크기의 입도가 낮은 점토질을 사용하여 얇고 치밀하게 조성하였으며, 모르타르층이 박락되고 상당기간이 경과 된 후 보수목적으로 마감한 것으로 추정된다. 굴 껍질을 소성하여 많든 석회를 모르타르로 사용한 것은 한국 고대 고분벽화 제작에 있어 유래 없는 사례이며, 내구성이 매우 떨어지는 특성을 지니고 있어 가야인들의 모르타르 제작기술이 동일시기의 고구려인들에 비해 상대적으로 떨어졌던 것으로 추측된다. Rigorous analysis was performed to identify the structure and materials of the murals to study techniques used on mural tombs of ancient Daegaya era(6th century). The murals were painted by applying mortar on the walls and the ceiling after building a stone chamber and creating ground layers on mortar layers. Mud was applied on most of the mortar layers on four sides of the walls except the ceiling. Sand was not used in mortar but was made of materials with pure calcium substances. In addition, shells in irregular sizes with incomplete calcination were mixed; and the mortar's white powder was inferred as lime obtained by calcination of oyster shells. Kaolinite($Al_2Si_2O_5(OH)_4$) was used in the ground layer, Cinnabar(HgS) was used for red pigment, Malachite($Cu_2CO_3(OH)_2$) for green and Lead white($PbCO_3{\cdot}Pb(OH)_2$) for white. Mud plaster was applied on the mortar and was composed thinly and densely using clayey of particle size smaller than that of medium sand. It was assumed that the finishing was for repair after long time had passed since the mortar layer came off. Using lime made with oyster shells as mortar is unprecedented in ancient Korean mural tombs and its durability was very poor, suggesting that Gaya's mortar production technique was relatively behind compared to that of Koguryo's in the same era.

폴리에틸렌글리콜 상이동 촉매를 이용한 디페닐메탄의 산화반응

이화수,문정열,박대원,박상욱,신정호 ( Hwa Soo Lee,Jeong Yeol Moon,Dae Won Park,Sang Wook Park,Jung Ho Shin ) 한국공업화학회 1993 공업화학 Vol.4 No.4

보통의 산화조건에서는 산화되기 어려운 diphenylmethane (pKa = 33.4)을 상이동 촉매와 고체인 potassium tert-butoxide를 염기로 사용하여 상온과 상압에서 산화시켜 benzophenone을 합성하였다. 4급염인 benzylytriethylammonium chloride, tetrabutyl ammonium bisulphate, tetrabutylphosponium chloride 등은 이 반응에 활성이 없었으나 18-crown-6와 폴리에틸렌글리콜은 촉매활성을 나타내었다. 같은 무게나 같은 몰수의 폴리에틸렌글리콜을 상이동 촉매로 사용한 경우 모두에서 diphenylmethane의 전화율은 폴리에틸렌글리콜의 사슬길이가 길수록 증가하였다. Diphenylmethane의 반출속도는 교반속도가 클수록 증가하였고, 비양성자성 용매인 DMF를 사용한 경우가 벤젠을 용매로 사용한 경우보다 높은 반응속도를 나타내었다. Diphenylmethane (pKa = 33.4), which is difficult to be oxidized in normal oxidation conditions, was oxidized to produce benzophenone at ambient temperature and atmospheric pressure by using phase transfer catalysts and solid potassium tert-butoxide as base. Quaternary salt such as benzyltriethylammonium chloride, tetrabutyl ammonium bisulfate, tetrabutylphosponium chloride, are ineffective catalysts for this reaction, but 18-crown-6 and polyethylene glycols showed catalytic activity. The conversion of diphenylmethane was increased with increasing chain length of PEG molecules when they are used as phase transfer catalysts both in equal molar and equal weight basis. The conversion of diphenylmethane was increased with the agitation speed, and aprotic solvent like DMF showed higher reaction rate compared with benzene.

속도제한 지원장치에 대한 운전자 인식도 및 도로환경 분석

이화수,조재호,임종현,이홍국,장경진,유송민,Lee, Hwa Soo,Cho, Jae Ho,Yim, Jong Hyun,Lee, Hong Guk,Chang, Kyung Jin,Yoo, Song Min 한국자동차안전학회 2015 자동차안전학회지 Vol.7 No.3

This study examined the Korean drivers' acceptance of SAS(Speed Assistance systems) and traffic sign conditions in Korea roads for SLIF(Speed Limit Information Function) that is a part of SAS. Exceeding the speed limit is a factor in the severity of many road accidents and SAS would help the driver to observe a speed limit by warning and/or effectively limiting the speed of the vehicle. SAS are in the initial phase in Korea, Korean drivers could not be familiar with automatical speed limiting during driving, SAS interface design would be considered to be more readily acceptable to the public. And advanced SAS have been introduced onto the market which are able to inform the driver of the current speed limit based on camera and/or digital maps based SLIF. These systems are based on external data using sensors, so environmental conditions are an important factor which could cause malfunction of SLIF functions.

도로 주행평가를 통한 능동 안전장치 연구

이화수,조재호,임종현,이홍국,장경진,유송민,Lee, Hwa Soo,Cho, Jae Ho,Yim, Jong Hyun,Lee, Hong Guk,Chang, Kyung Jin,Yoo, Song Min 한국자동차안전학회 2015 자동차안전학회지 Vol.7 No.1

This study examined the drivers' acceptance level of various active safety features with Korean drivers on Seoul urban and city roads. The test vehicle, 2013 Cadillac ATS, was equipped with FCA(Forward Collision Alert), LDW(Lane Departure Warning), SBZA(Side Blind Zone Alert), FRPA(Front/Rear Park Assist), RCTA(Rear Cross Traffic Alert), ACC(Adaptive Cruise Control), and AEB(Autonomous Emergency Braking). Participants had chances to run the tests on those systems in the parking lot accompanied by the 106km long stretch of predetermined route including local road and interurban highway in Seoul and Gyeonggi-do under normal traffic flowing environment. After the test, participants completed a series of questionnaires about the features they experienced. The results revealed that RCTA and SBZA systems received more favourable ratings compared to the other features in avoiding crashes. The respondents preferred sound alerts to haptic ones even though haptic warning methods were better in providing directional information.

제한속도정보제공장치(SLIF)에 대한 한국 환경 평가 분석

이화수,심지환,임종현,이홍국,장경진,유송민,Lee, Hwasoo,Sim, Jihwan,Yim, Jonghyun,Lee, Hongguk,Chang, Kyungjin,Yoo, Songmin 한국자동차안전학회 2015 자동차안전학회지 Vol.7 No.4

Exceeding the speed limit during vehicle driving is a key factor in the severity of lots of road accidents, and SLIF(Speed Limit Information Function) application is in the initial phase in Korea. SLIF helps the drivers to observe a speed limit when they are driving by providing alert and informing the current limit speed information based on external data using camera and/or digital map, for that reason, environmental conditions could be causes of SLIF malfunctions. In this study, design adequacy analysis of SLIF in respect of false recognition as the Korea traffic environment has been performed. As tentative results, road conditions and structure of speed limit sign as well as system performance often caused misrecognition.

Aliquat 336 상이동 촉매하에서 디페닐메탄의 산화반응에 관한 속도론적 연구

이화수,문정열,나석은,박대원 ( Hwa Soo Lee,Jeong Yeol Moon,Suk En Na,Dae Won Park ) 한국공업화학회 1994 공업화학 Vol.5 No.2

A mechanism for the synthesis of benzophenone from oxidation of diphenylmethane under Aliquit 336 phase transfer catalyst is investigated in this study. The production rate of benzophenone increased with the increasing amount of Aliquat 336 and potassium term-butoxide. At tow concentrations of diphenylmethane and oxygen, the reaction order was first with the concentrations of diphenylmethane and oxygen respectively, but it approached to zero order at high concentrations. Tert-butyl alcohol, by-product of the reaction, inhibited the formation of benzophenone. Experimental results fit fairly well to the following initial reaction rate equation derived from reaction mechanism.

보물 제1752호 고창 선운사 소조비로자나삼불좌상 재질특성 및 제작기법 연구(1): 소조불상 주요 구성재료 분석

이화수,이한형,한규성,Lee, Hwa Soo,Lee, Han Hyoung,Han, Gyu-Seong 한국문화재보존과학회 2020 보존과학회지 Vol.36 No.6

보물 제1752호 고창 선운사 소조비로자나삼불좌상 보존을 위해 불상을 구성하는 주요 재질에 대한 과학적 분석을 실시하였다. 소조불상을 구성하는 토양층 분석결과 중립사 이상의 모래와 세립사 이하의 토양이 3:7의 비율로 쓰인 것으로 나타났으며, 닥나무의 인피섬유도 함께 확인되었다. 따라서 소조토는 모래와 풍화토를 혼합하고 분산방지를 위해 닥지를 섬유질로 첨가한 것을 알 수 있다. 수종분석 결과, 아미타여래, 비로자나불, 약사여래의 좌대 및 팔 부위를 구성하는 목재는 모두 경송류(Hard pines)로 식별되었으며, 개금층 분석 결과, 시료 단면에서 3개의 층위가 확인되었다. 불상의 나발은 석영, 조장석, 미사장석, 운모, 자철석 등 토양성 물질로 구성되었으며, 나발의 표면은 자철석이 함유된 흑색물질을 이용하여 표면을 채색한 것으로 판단된다. In this study, to conserve the clay seated Vairocana Buddha triad in Seonunsa temple, Gochang (Treasure 1752), the primary materials employed for creating the clay Buddha statues were scientifically analyzed. By analyzing the soil layer constituting the Buddha statues, it is observed that the said layer comprises sand having particle size greater than that of medium sand and soil having particle size smaller than that of fine sand, which were used in a ratio of 7:3, along with the bast fibers of paper mulberry (Broussonetia kazinoki). Hence, the aforementioned soil layer is composed of a mixture of sand and weathered soil, along with bast fibers to prevent scattering. By analyzing the tree species, it is found that the wooden materials constituting the bottom board and the interior of Buddha's sleeves of the Amitabha Buddha statue, Vairocana Buddha statue, and Medicine Buddha statue are hard pines (Pinus spp.). Additionally, three layers are found in the cross section of the gold layer. Furthermore, each of the hair sections of the Buddha statues is composed of earthy materials such as quartz, albite, microcline, mica, and magnetite, and the hair surface was painted by incorporating black materials containing magnetite.

초대칼럼 - 기후변화협약, 정부의 의지가 중요하다

이화수,Lee, Hwa-Su 대한석유협회 2009 석유와 에너지 Vol.273 No.-

iGLAD 사고 분류 유형을 이용한 자전거 탑승자 교통사고 분석

이화수,장은지,임종현,이지민,김재훈,송봉섭,Lee, Hwasoo,Jang, Eunji,Yim, Jonghyun,Lee, Jimin,Kim, Jaehoon,Song, Bongsob 한국자동차안전학회 2018 자동차안전학회지 Vol.10 No.1

This paper reports an analysis of cyclist accident cases with respect to passenger vehicles on Korean roads. A typology based on Initiative for the Global Harmonization of Accident Data (iGLAD) code book is applied to a traffic accident analysis system(TAAS), which has the real-world crash data on Korea roads, to understand the accident scenarios in more detail and efficiently. Similarly this typology has been used for Germany In-Depth Accidents Study (GIDAS) as well. The accident data analysis with consideration of the typology of Korean road conditions may prioritize traffic safety issues regarding cyclists and is aimed to develop an Automatic Emergency Braking (AEB) system for cyclist. In summary, this paper characterizes and analyzes the scenarios of cyclist crashes with passenger car. The most common accident scenarios on Korean roads are Car-to-Bicyclist Nearside Adult (CBNA) and Car-to-Bicyclist Longitudinal Adult (CBLA), which are more than 86% of total accidents cases. Therefore, it is inferred that AEB cyclist system should include these accident types in the operational design domain to reduce more fatality in Korea.

PSIM 소프트웨어에 의한 STATCOM 시스템 시뮬레이션

이화수(Lee Hwa-su),김용헌(Kim Yong-heon),이은웅(Lee Eun-woong),이동주(Lee Dong-ju) 대한전기학회 2003 대한전기학회 학술대회 논문집 Vol.2003 No.4