혈액투석중인 말기신부전 환자에서 Fludrocortisone acetate (FCA) 투여 후 혈청 칼륨 저하 효과

류봉관,강대웅,정지용,윤나라,신병철,박경희,정종훈,김현리 朝鮮大學校 附設 醫學硏究所 2005 The Medical Journal of Chosun University Vol.30 No.1

Background: Hyperkalemia is a commonly encountered problem in dialysis patients with end-stage renal disease. In this study we evaluated the effect of mineralocorticoid therapy (fludrocortisono acetate) on serum potassium level in the serum of hyperkalemic end-stage renal disease patients. Methods: Fourteen patients on hemodialysis receiving fludrocortisone acetate (FCA) 0.1 mg/day were observed for 2 months periods. Consecutive monthly biochemical profiles were compared for the druration of the pre-and post-treatment of FCA. Result: Fourteen patients with mean age (±SE) of 51.5 years (4 males and 10 females) and mean hemodialysis period of 51.9 months were studied. Mean serum potassium levels significantly fell (p<0.05) during the post-FCA period (5.2±0.66 mEq/L) compared with potassium levels during the pre-FCA (5.8±0.43 mEq/L) period. Pre-and post-FCA values were not different for sodium, chloride, protein, albumin, AST/ALT, glucose, blood nitrogen, creatinine, phosphate and calcium. Conclusions: FCA appears to decrease serum potassium value in patients with end-stage renal disease. These results suggested that FCA could be effective to treat hyperkalemia without any adverse effect in patients undergoing hemodialysis.

방한 일본인 관광객의 패션상품 구매행동에 관한 연구

류덕환,조지현,서철현 啓明大學校 生活科學硏究所 2002 科學論集 Vol.- No.-

The purpose of this study was to investigate demographic profiles, purchase motivation, and purchase behavior of consumers of inbound tourists. More specially, the samples chosen for the study were Japanese inbound tourists from Dongdaemoon fashion market by means of questionnaire method. The reason why Japanese are the highest proportion in inbound tourists. Of 250 Japanese tourists who had buying experienced answered data, 210 data were usable. The results were as follows. The primary motivation of purchasing fashion goods was concerned with the price. They had chance to buy various items, especially they bought lots of T-shifts in the number of purchase items. In addition, Japanese tourists preferred more natural textiles. With regard to the important consideration when they purchase fashion goods, design, price size, usefulness, and color were more important. Most Japanese tourists were officers and students, and higher educated in demographic variables. Their age were in twenties, thirties, and women tourists were a little more than men.

암모니아성 질소(NH_4^+-N)제거를 위한 제올라이트성 물질의 제조

류태공,류재춘,한명식,김철규,김영호,양현수 忠南大學校 産業技術硏究所 2002 산업기술연구논문집 Vol.17 No.2

The objectives of this study were to synthesize high ion-exchangeable zeolitic materials prepared from coal fly ash and to determine the adsorption capacities for the removal of NH_4^+4-N in wastewater For comparison. NH_4^+-N adsorption capacities of commercial, natural, and synthetic(4A type, Si0_2/Al_2O_3=1.98. Na_2O/SiO_2=1.54. H_2O/Na_2O=46.95) zeolites were investigated at the same condition. Zeolitic materials were prepared from coal fly ash by hydrothermal reaction with various NaOH concentrations at the reaction time of 4h and the reaction temperature of 100℃. It showed that the zeolitic material prepared at a 4M-NaOH concentration had the most NH_4^+-N adsorption capacity. Theremoval efficiency of NH_4^+-N on the zeolitic material was little difference compared with those on natural and commercial zeolites, though it was lower than that on a synthetic zeolite(4A type). As a result, it is expected that the prepared zeolitic material could be applicable to adsorbent for the NH_4^+-N removal in wastewater.

고유함수전개법을 이용한 비대칭 유전체 원주공진기의 공진특성해석

류원열,민경호,장중호,전오곤,이창화,최현철 경북대학교 센서기술연구소 1998 센서技術學術大會論文集 Vol.9 No.1

The resonant frequency of the dielectric rod resonator which is surrounded by cylindrical cavity can be calculated very exactly by using eigenfunction expansion method in the concept of electric and magnetic wall from the symmetry. But if the supporter is put in the cavity, the symmetry disappears. Thus this method has some errors. In this paper, the resonant frequency of the asymmetric dielectric rod resonator was calculated by using the eigenfunction expansion method. Also, the effect of the supporter was discussed. Then we found that the resonant frequency was more affected in the case of TM mode than TE or Hybrid modes as the length of the supporter was longer.

과학고 및 영재고 Research and Education (R&E) 운영실태 분석 및 활성화방안 제안 : R&E 운영담당자 면담사례를 중심으로

정현철,류춘렬,채유정 韓國英才學會 2012 영재교육연구 Vol.22 No.2

The purpose of this study was to investigate the current status of R&E programs in gifted high schools/science high schools and to provide suggestions for the better program. The sample included 21 R&E coordinators in the gifted high schools and science high schools. They filled out the survey, asking about the R&E program; then, the researchers interviewed the coordinators based on the answers of the survey. The results are as follows: 1) The R&E guidelines and related materials were not enough to use. 2) At the planning step, students and the mentors received were provided a little information, such as ethical issues, students' information, the roles of mentors/ students, mentor's research interest areas and products, etc. 3) At the research step, 80% of the schools had the monitoring process but the details were not written and saved. 4) At the evaluation step, the rubric of the product evaluation existed; the rubric of performance process were established by half of the schools. 5) At the closing step, 100% of the schools had the final product materials; the results of the evaluation and the information of the mentors were saved by 2/3 and 1/3 of the schools, respectively. Discussions and suggestions were included for the better R&E programs. 본 연구에서는 R&E 프로그램의 운영지원현황 및 실태를 알아보기 위하여 R&E 운영단계를 준비-계획-실행-평가-종료 5단계로 구분하여 조사 및 분석이 이루어졌다. 총 18개 과학고와 3개 영재학교 R&E 운영담당자들이 본 연구에 참여하였다. 2010년 12월, 전수조사를 목적으로 각 학교에 설문지를 배포하였으며, R&E 운영담당자 21명(100%)이 설문에 응답하였다. 주요 결과는 다음과 같다. 첫 번째, 준비단계에서 학생의 R&E 수행지침은 적절히 이루어지지 않고 있었으며, 운영을 위해 참고할 수 있는 자료도 매우 부족한 것으로 나타났다. 두 번째, 계획 단계에서 지도자를 대상으로 윤리적인 문제, 참고자료, 학생배경 특성 등에 관한 안내가 적절히 이루어지지 않고 있었으며, 학생들에게 지도자의 의무와 역할, 연구정보 및 업적 등에 대한 정보제공이 충분히 이루어지지 않고 있었다. 세 번째, R&E 실행단계에서는 80%의 학교가 수행 점검을 실시하고 있었으나 세부적인 점검내용에 대한 기록은 이루어지지 않고 있었다. 네 번째, 평가단계에서 산출결과의 평가기준은 모든 학교가 갖추고 있었으나, 수행 과정에 대한 평가기준은 약 절반의 학교만 가지고 있었고, 평가비율에 발표내용과 결과보고서 비율이 높게 나타나 평가가 ‘결과’에 많은 비중을 두고 있는 것으로 나타났다. 마지막으로, 종료단계에 결과자료집은 100% 보관되고 있었으나 평가결과는 2/3 학교가, 그리고 지도교수 정보는 약 1/3의 학교만이 보관하고 있는 것으로 나타났으며, 학생관찰 내용 및 면담자료도 비교적 잘 보관되지 않는 것으로 나타났다. 이와 같은 결과를 바탕으로, 효과적인 R&E 프로그램 운영을 위한 운영개선 지원방안을 제시하였다.

스키시즌권 구매자들의 스키장별 선호도 조사

장현철,김경식,방준현,최천진,엄정식,김응준,이루지 한국스포츠리서치 2004 한국 스포츠 리서치 Vol.15 No.2

The purpose of this study was to examine the perception and preference of skiers in a bid to provide ski resorts with useful information about successful positioning strategy. The subjects in this study were 9,722 skiers who purchased season tickets from N web site that sold ski season tickets. Their online purchasing route and page view were analyzed to find out what factors affected their purchase of ski season tickets. The findings of this study were as follows: First, 78 percent of the people investigated were make, and 22 percent were female. By age, the largest group was in their 20s(5,344 skiers), followed by those in their 30s(3,434), those in their 40s(631) and teenagers(229). Second, their page view rate with Yangji recorded highest with 24%, followed by Sungwoo Resort with 23% and Chonmasan with 13 percent. Third, by geographic area, the skiers from southern Gyeonggi province bought the largest number of tickets for the 2002/2003 season, followed by Gangweon province residents and northem Gyeonggi province dwellers. In the case of the 2003/2004 season, those from Gangweon provinece pruchased the most tickets, followed by southern Gyeonggi province dwellers and north Gyeonggi province residents.

가상현실 기법의 활용이 지식 성취도 향상에 미치는 효과 : 눈의 구조와 기능 내용을 중심으로 The Structure and Function of Eye

심규철,류수정,김현섭,김희수,박영철 한국과학교육학회 2003 한국과학교육학회지 Vol.23 No.1

The purpose of present study was to develop teaching-learning materials based virtual reality technology(VRT), and to examine the effect of it on the knowledge achievement of biology. Authoring tool of virtual reality(VR) was 3D Webmaster made in Superscape Ltd., United Kingdom. Educational materials was developed for the structure and function of eye of life field in the 10th science. It was learner-directed and interactive educational material using the Web-based and desktop VR. The result showed a meaningful improvement on the achievement. Using 3D VR shows the potential of available education media in the next generation as science teaching-aided material, which especially was efficient in the understanding and perception of abstract or difficult to direct experience learning contents.

수열합성 반응에 의한 3mol % 지르코니아 세라믹의 Fe2+, Fe3+, Er3+치환에 따른 상변태와 물성 변화

변지철, 이현철, 김택남, 류재경 배재대학교 공학연구소 2017 공학논문집 Vol.19 No.1

Zirconia is a heat-resistant material with a high melting temperature(2700℃) and has low thermal conductivity and excellent corrosion resistance. However, application has been limited due to brittleness, which is a disadvantage of ceramic materials. As a way to improve this, the addition of Y3+ improves the strength by phase transformation, which can improve the brittle problem, which is a disadvantage of ceramic. Many studies have been conducted on the addition of Y3+ after the addition has been found to be more efficient than the other additives. In this experiment, have studied the additives that replace this Y3+. Expeiments on the possibility of replacing Y3+ by adding an alternative additive considering Zr-sol(Fe2+, Fe3+, Er3+) in consideration of Atomic size, Crystal ionic raddi and Effective Ionic raddi. ZOC(ZrOCl2*8H2O) was dissolved in distilled water and synthesized by hydrothermal synthesis at 160℃ for 24hours. The formed Zr-sol was separated into a supernatant and precipitate. The supernatant was washed with distilled water, and the presence of chloride ion was confirmed using AgNO3. And add to the cleaned Zr-sol an additive that is believed to be a substitute for Y3+. The prepared Zirconia was calcined at 900℃ for 2hours, and the crystal phase was analyzed by XRD similar that of YSZ. The calcined powder was uniaxial pressed and sintered at 1500℃ for 2hours. The sintered specimens were first measured for specific gravity. And the particle size distribution, EDAX and FESEM were measured. 지르코니아는 고온에선 용융하는 (2700℃) 낮은 열전도율과 부식저항이 우수한 세라믹이다. 이에 우수한 파괴인성을 주기 위해 3 mol % Y를 첨가하게 되고, 상온에서 정방정 상으로 존재함으로써 파괴인성이 증가한 것으로 알려져 있다. 따라서 본 실험에서는 Y와 유효 원자 반경이 유사한 Er3+ (89pm)를 첨가함으로써, 과연 어떤 변화가 나타나는지를 알아보았다. 또한 원자가가 유사한 Fe3+와 Fe2+ 를 첨가하여 물성변화와 상변화를 조사하였다. 연구결과 이온 반경이 Y와 유사한 Er3+에서는 완전한 정방정상과 밀도, 투광율 (일부 파장은 제외)을 나타내었으나, 이온 반경이 약1/2 인 Fe2+, Fe3+를 첨가한 경우에는 단사정과 비정질 그리고, 650nm이하의 파장에서는 거의 투광하지 않는 현상을 보였다.

신사구체 경변증을 나타내는 FGS/NgaKist mice 간장에서 사이토크롬 P4501A1/2 단백질 발현

정규식,현병화,이철호,박상준,최양규,류시윤,이차수,민병길 대한해부학회 1997 Anatomy & Cell Biology Vol.30 No.2

PbO-SiO_2계 유리에서의 유동 특성

차재민,김웅식,송현진,이병철,류봉기 釜山大學校生産技術硏究所 2002 生産技術硏究所論文集 Vol.61 No.-

유리에 관한 연구에 있어 점도는 가장 중요한 특성중의 하나로 여겨지며, 용융 상태, 작업 온도, 서냉 온도 또는 결정화 속도에 등과 같은 인자와도 크게 관계가 있다. 특히 각기 다른 조성을 가진 유리에서도 점도는 매우 다양하며, 온도에 크게 영향을 받는다. PbO-SiO_2 이성분계 유리에서는 PbO가 첨가됨에 따라 점도의 온도의존성이 커지고 표면장력이 감소하였다. 온도와 시간에 따른 spreading ratio를 비교한 결과 PbO의 함량이 증가함에 따라 유동성이 증가하였고 온도에 따른 유동성의 증가율도 크게 증가하였다. 그리고 일정한 온도에서 시간의 경과에 따른 유동성의 증가율은 감소하였다. The viscosity of a glass is one of the most important properties. It determines the melting conditions, the temperatures of working and annealing, fining behavior and devitrification rate. The viscosities of different glasses vary enormously with composition and are strong functions of temperature. On adding PbO in the PbO-SiO_2 binary system, the temperature dependence of the viscosity was large, the surface tension decreased. In the temperature and time dependence of spreading ratio, the spreading ratios of glass increased with increase PbO content and the rate in its increase decreased with time at constant temperature.