튜브형 가열로 반응기를 이용한 초미립 SiO2 입자의 생성 및 증착 제어

현봉수,김교선 ( Bong Su Hyun,Kyo Seon Kim ) 한국화학공학회 1995 화학공학의이론과응용 Vol.1 No.1

혼파초지에서 질소시비수준과 방목율이 목초 및 육우생산에 미치는 영향

현봉수,김문철,김영호,송성언,이승협 제주대학교 농과대학 제주도축산문제연구소 1986 畜産論叢 Vol.1 No.1

Effects of N fertilizer levels and stocking rates on beef production in a mixed pastiire of orchard-grass, perennial ryegrass, tall fescue, red clover and alsike clover were studied using 3 levels of N fertilizer (50, 100 and 200 kg/ha) and 3 stocking rates (3,4 and 5 head /ha). The summarized results are the following; 1. Increasing nitrogen fertilizer on the mixed pasture increased dry matter yield and protein content(P<0.05) of the pasture species. The stocking rate did not influence either dry matter yield or protein content. 2. The percentage of pasture species increased and that of weeds decreased with increasing N fer-tilizer levels. lncreasing stocking rate from 3 to 5 heads/ha significantly influenced that of the other pastures and weeds. 3. Herhage intake per animal increased at the lower stocking rate, but total herbage intake per ha increased at the higher stocking rate, Increasing nitrogen fertilizer decreased herbage intake per animal , but slightly higher intake per animal was obserbed at 5 head stocking rate. 4. No significant difference in weight gain/ha was found among N levels and stocking rates ussd. Live weight gain per animal was greater at the higher N level and also at the louer stocking rate.

만성피로 증후군 1례

현종주,이관용,강봉수,강희철,윤방부 대한가정의학회 1996 Korean Journal of Family Medicine Vol.17 No.7

Molecular cloning of GnRH1 gene and GTH cDNAs of the protogynous longtooth grouper, Epinephelus bruneus

현경만,정형복,임봉수,허성표,이영돈,박지권,김세재 한국유전학회 2010 Genes & Genomics Vol.32 No.6

In teleosts, gonadotropin-releasing hormone (GnRH) and gonadotropin hormone (GTH) play important roles in regulating gonadal development and maturation. In Southeast Asia, the longtooth grouper, Epinephelus bruneus, is a commercially important aquaculture fish. In this study, we cloned and characterized the longtooth grouper GnRH1 gene and cDNAs of three gonadotropin subunits (GTHα, FSHβ, LHβ). The GnRH1 gene of longtooth grouper was 4,032 bp long, and contained four exons, 61, 151, 99, and 423 bp long. GTHα, FSHβ, and LHβcDNAs were 509, 576, and 579 bp, respectively. Phylogenetic and Southern hybridization analyses revealed that the longtooth grouper GTH subunits were evolutionarily close to those of groupers and are one-copy genes. RT-PCR analyses showed that GTH subunit mRNAs were expressed at a higher level in the pituitary glands of immature fish than in those of mature fish, suggesting a role in gonadal maturation.

운영자관점의 버스운행 정시성 평가지표 개발

현경,손봉수(Son, Bong-Su) 대한교통학회 2010 대한교통학회 학술대회지 Vol.62 No.-

초미립 TiO2 입자 제조용 튜브형 가열로 반응기의 모델연구

김교선,현봉수 한국화학공학회 1995 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.33 No.2

튜브형 가열로 반응기에 의한 TiO₂초미세 분말 제조공정의 수치모사 결과를 제시하였다. 반응기 내의 모델식으로는 연속식, 에너지식, 물질수지식, 에어로졸의 0차, 1차, 2차모멘트식을 고려하였고, 에어로졸의 동력학식에서는 TiCl₄의 반응속도, TiO₂ 핵화속도, TiO₂ 입자의 충돌, 확산과 열영동 현상을 포함하였다. 가열온도가 낮을수록, 초기 TiCl₄농도가 높을수록 또는 전체 기체유량의 속도가 빠를수록 생성된 TiO₂ 입자의 농도가 높게 나타났고, 반면에 반응온도, TiCl₄초기농도가 높을수록 또는 전체 기체유량의 유속이 느릴수록 TiO₂ 입자의 직경은 크게 나타났다. The results of numerical model for a tube furnace reactor were proposed to manufacture ultrafine TiO₂ powders. The model equations such as continuity, energy balance and mass balance equations, and the 0th, 1st, and 2nd moment equations of aerosols were considered. The phenomena such as TiCl₄ reaction rate, TiO₂ nucleation rate and the coagulation, diffusion and thermophoresis of TiOz powders were included in the aerosol dynamic equations. It is found that the TiO₂ particle concentration becomes higher, as the furnace temperature decreases and also as the inlet TiCl₄ concentration and the total gas flow rate increase. On the other hand, the TiO₂ particle size increases, as the furnace temperature and the inlet TiCl₄, concentration increase and also as the total gas flow rate decreases.

문제정보량과 학습접근방식에 따른 고등학생의 물리문제해결과정 분석

박윤배,현봉수 한국물리학회 2006 새물리 Vol.53 No.4

The purpose of this study is to analyze physics problem solving processes of high school students according to amount of information and type of learning in the area of 'Force and Motion' in high school science. A physics problem test and a prerequisite knowledge test were developed. The physics problem test consisted of four suitable information problems and four unnecessary information problems. Two students having a macroscopic learning approach and another two students having a microscopic learning approach were selected. Then, the students solved the physics problem test and the prerequisite knowledge test. A protocol has made by recording the students' solving processes. After solving the problems, the students expressed their confidence by using five-point Likert scale, after that they were interviewed about the unclear portion individually. In the suitable information problems, the ratios of success and confidence were higher then they were for the unnecessary information problems, the solving time was shorter, and the repeating frequency was less. In the unnecessary information problems, the students used a random strategy more than they did for the suitable information problems. Students having a macroscopic learning approach. Took less total time and less time on each stage to solve the problems than the students having a microscopic learning approach they also used a larger proportion of the time on a planning step and a smaller proportion in the execution step. Macroscopic students tended to solve more unnecessary information problems correctly. The time difference according to the amount of information was smaller for the microscopic students than for the macroscopic students. The confidence of the microscopic students tended to be lower in unnecessary information problems than in suitable information problems. 본 연구는 고등학교 학생들이 물리분야의 힘과 운동에 관한 문제를 해결하는 과정을 발성 사고법을 이용하여 녹음한 후, 응답원안 분석을 통하여 그들의 문제해결전략 및 단계별 소요 시간 비율, 해결 전략, 자신감, 해결단계 반복횟수 등의 문제해결과정과 결과가 문제에 제시된 정보량, 문제 해결자의 학습접근방식에 따라 어떻게 다른지를 분석하였다. 그 결과, 정보가 알맞게 제시된 문제에서 성공률이 더 높았고, 소요시간도 짧았으며, 단계반복회수도 적게 나타났고, 해답에 대한 자신감도 높았다. 거시적 접근방식의 학생들의 소요시간이 짧았으며, 계획을 오래 하는 것으로 나타났다. 거시적 접근학생들은 불필요한 정보가 제시된 문제에서 성공률이 더 높았고, 소요시간의 변화나 자신감의 변화도 적었다.

간략화된 MCVD 반응기에서의 초미립 SiO2 입자의 제조 및 증착제어

채범산,현봉수,김교선 ( Bum San Chae,Bong Su Hyun,Kyo Seon Kim ) 한국화학공학회 1995 화학공학의이론과응용 Vol.1 No.2

연구논문 - 무기 / 촉매 : 초미립 TiO2 입자 제조용 튜브형 가열로 반응기의 모델연구

김교선,현봉수,장희동 ( Kyo Seon Kim,Bong Su Hyun,Hee Dong Jang ) 한국공업화학회 1994 한국공업화학회 연구논문 초록집 Vol.1990 No.3

간략화된 MCVD 반응기에서의 초미립 SiO2 입자 증착특성

김교선,현봉수 한국화학공학회 1996 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.34 No.2

간략화된 MCVD 반응기에서 가열로 설정온도, 전체기체유량 및 초기 SiC1₄ 농도 등의 공정조건을 변화시키데 SiO₂입자의 증착특성에 대하여 이론적/실험적으로 연구하였다. 수치모사에서는 반응기 내의 전달현상식과 에어로졸 동력학식을 고려하였으며 수치모사에 의한 증착구간에서의 증착효율은 실험결과와 비교적 잘 일치하였다. 본 연구의 공정조건 범위에서는 가열로 설정온도가 높을수록, 초기 SiCl₄ 농도가 낮을수록 SiO₂ 입자의 증착효율은 높게 나타났으며, 전체기체유량이 증가할수록 SiCl₄의 전환율과 증착효율은 감소하였다. The deposition characteristics of SiO₂ particles were investigated in simplified MCVD reactor theoretically and experimentally, changing the process conditions of furnace setting temperature, total gas flow rate and inlet SiCl₄ concentration. The transport phenomena equations and aerosol dynamic equations inside reactor were considered in numerical simulation. The computed deposition efficiencies in deposition zone were in good agreement with the experimental results. For the process conditions in this study, it is found that the deposition efficiency of SiO₂ particles increases as the furnace setting temperature increases, also as the inlet SiCl₄ concentration decreases. As the total gas flow rate increases, the SiCl₄ conversion and deposition efficiency decrease.