프로펜 메타세시스에서 Re₂O/Al₂O₃촉매의 활성에 미치는 알킬주석의 첨가영향

안호근 順天大學校 1994 論文集 Vol.13 No.1

□The effect of alkyltin(R₄Sn, R=methyl, ethyl, butyl) addition on the activity of the metathesis of propene over ??/Al₂O₃catalysts at 298K was studied under atmospheric pressure. The amount of initial carbenes formed on the catalysts was estimated by measuring quantitatively the amount of CH₄evolved when alkyltin was added to the catalysts. The initial carbenes(Re=R'CH, R'=H, methyl, propyl) were effectively generated by a reaction between the added alkyltin and Re on the surface, resulting in greatly enhancing their metathesis activities. Turnover frequency(TOF) for the ??/Al₂O₃ catalysts was nearly constant. It was therefore found that the catalyst with low loading was greatly improved in the activity by adding alkyltin.

니켈 촉매에 의한 동백유의 수소화에 관한 연구

안호근,손보균,임한진 순천대학교 공업기술연구소 1998 工業技術硏究所論文集 Vol.12 No.-

The reaction conditions were investigated to prepare the hardened oil with suitable properties from Camellia japonica oil by catalytic hydrogenation in batch reactor at atmosphere. The nickel-based catalysts were used, and the hydrogenation activity of the catalyst was measured as iodine value. The commercial Pricat-9920 catalyst was highly active. The hydrogenation rate over Pricat-9920 catalyst was increased with increasing reaction temperature to 180℃, but decreased over 180℃ because the dissolution of hydrogen in the oil was difficult at high temperature. Also, the rate depended on the amounts of catalyst used, the flow rate of hydrogen, and agitation rate, which were deeply related to the diffusion of hydrogen in the pore of the catalyst. The hardened oil with melting point 30~40℃ was obtained at reaction time 4~6hr, reaction temperature 180℃, the amounts of catalysts 0.2%Ni(w/v), and the flow rate of hydrogen 50cc min^(-1). The relationship between iodine value and melting point was linear, so the iodine value could be easily estimated from the melting point.

자동차 폐촉매의 재활용을 위한 재생방법에 관한 연구

안호근,최병민,김병훈 順天大學校 1999 論文集 Vol.18 No.1

The recovery of the platinum group metals on the spent automotive catalysts is economically very important because of their high value and stable supply, but the spent autocatalysts still keep the inherent oxidation activity. The regeneration method was studied by treating with various acid solutions and/or air stream, the regenerated activity was investigated in the ethylene oxidation in a flow reactor. The oxidation activity showed maximum at 0.01vol% HNO₃solution, and was decreased with increasing the HNO₃concentration because the active metals or supports were dissolved into acid solution. Also, the activity was enhanced with increasing the air treatment temperature, and decreased at higher temperature than 300℃. The maximum activity was obtained at 300℃. Therefore, the oxidation activity of the spent autocatalysis could be effectively regenerated by the treatment of nitric acid solution and air stream.

酸化物 擔體上에서의 金屬 카아보닐의 化學 및 그의 觸媒作用

安虎根 순천대학교 공업기술연구소 1993 工業技術硏究所論文集 Vol.7 No.-

The surface chemistry and the structure of Co_2(CO)_8, Re_2(CO)_10, and Fe_3(CO)_12 fixed on solid oxide such as Al_2O_3, SiO_2, and MgO at 298 K were investigated by means of TPDE, GEA, IR, etc, and the activity of the prepared catalysts was evaluated by the hydrogenation of butadiene. At higher contents of cobalt on alumina, Co_2(CO)_8 was decomposed to Co_4(CO)_12, and Co_2(CO)_8(2.0wt%) on dehydroxylated alumina had at least two species, that is, the adsorbed Co_4(CO)_12 and the ligated Co_2(CO)_6. The deposited Co_2(CO)_8 and Fe_3(CO)_12 were completely decomposed at about 673 K, but Re_2(CO)_10 without the bridged CO at higher temperature (1023 K). Also, the decomposition temperature of Co_2(CO)_8 on various supports increased with the order MgO > Al_2O_2 > SiO_3, and was consistent with the basicity of the support surface. The highly dispersed metal catalysts with zero-valent atoms could be prepared by thermal pyrolysis of their metal carbonyls which were deposited on dehydroxylated alumina without hydroxyl groups. In the case of cobalt carbonyl the dispersion of Co was close to unity, and it showed very high activity in the hydrogenation of butadiene so that proceeded to deep hydrogenation.

최단경로문제에서 k개의 치명호를 찾는 방법

안재근,정호연,박순달 한국경영과학회 1998 韓國經營科學會誌 Vol.23 No.4

This paper deals with a mathematical model and an algorithm for the problem of determining k most vital arcs in the shortest path problem. First, we propose a 0-1 integer programming model for finding k most vital arcs in shortest path problem given the ordered set of paths with cardinality q. Next, we also propose an algorithm for finding k most vital arcs in the shortest path problem which uses the 0-1 integer programming model and shortest path algorithm and maximum flow algorithms repeatedly. Malik et al. proposed a non-polynomial algorithm to solve the problem, but their algorithm was contradicted by Bar-Noy et al. with a counter example to the algorithm in 1995. But using our algorithm. the exact solution can be found differently from the algorithm of Malik et al.

충전층내의 펄스입력 및 응답농도 측정으로부터 충전층의 공극률 산출

오준,김용철,안호근 순천대학교 공업기술연구소 1998 工業技術硏究所論文集 Vol.12 No.-

The packed bed void fraction was estimated by moment method for nitrogen pulse-input and output concentration of packed bed of porous particles(MS-3A, MS-5A) and non-porous particles (glass beads). Chromatographic experiment was carried out at room temperature, atmospheric pressure and laminar flow. The packed bed void fractions of MS-3A and MS-5A with average diameter 0.18㎝ were 0.39 and 0.40, respectively. The void fractions of glass beads with average diameter 0.12㎝ and 0.30㎝ were 0.43 and 0.44, respectively. The packed bed void fractions from density measurement of both porous and non-porous particles were in accord with the values from chromatography within 10% error.

대한방사선종양학회지 게재 논문의 통계적 오류 현황

박희철(Hee Chul Park),최두호(Doo Ho Choi),안성복(Song-Vogue Ahn),강진오(Jin Oh Kang),김은석(Eun-Seog Kim),박원(Won Park),안승도(Seung Do Ahn),양대식(Dae Sik Yang),윤형근(Hyong Geun Yun),정은지(Eun Ji Chung),지의규(Eui Kyu Chie),표홍렬( 대한방사선종양학회 2008 Radiation Oncology Journal Vol.26 No.4

목 적: 본 연구는 대한방사선종양학회지 게재 논문의 통계 오류 현황을 파악하고 이에 근거한 문제 제기를 통해 학회지의 학술적 발전에 기여하고자 하였다. 대상 및 방법: 2006∼2007년 사이에 대한방사선종양학회지에 게재된 총 77편의 논문을 연구 대상으로 하였다. 각각의 논문에 적용된 통계 방법론의 적정성 평가는 통계점검표를 활용하였다. 통계점검표에는 연구의 종류, 통계기법의 사용 범위, 각 논문에 적용된 통계 기법의 종류, 통계적 기법 적용의 타당성 항목이 포함되었다. 통계 오류는 ‘생략의 잘못’과 ‘시행의 잘못’ 항목으로 나누었다. 한 논문에서 서로 다른 항목이 여러 가지 관찰된 경우 각각 횟수로 측정하였다. 같은 항목이 2회 이상 측정된 경우 1회로 횟수를 측정하였다. 통계 전문가가 개별 논문을 대상으로 통계점검표를 작성하였다. 일차 평가자가 방사선종양학 전문가가 아닌 것에서 올 수 있는 평가 오류가 있을 수 있으므로 개별 통계점검표는 간행위원회에서 한 차례 더 세부 점검을 하였다. 작성된 통계점검표의 통계 분석은 SAS (version 9.0, SAS Institute, NC, USA) 소프트웨어를 이용하였고 빈도분석을 시행하여 각 항목의 빈도와 백분율을 산출하였다. 결 과: 총 77편 중 원문을 다운로드 할 수 없었던 4편을 제외한 73편의 게재 논문을 대상으로 평가하였다. 증례보고는 5편, 원저 논문은 68편이었다. 대상 논문 중 46편의 논문에서 통계적 추론을 사용하였고, 16편의 논문에서 단순한 기술통계를 사용했으며, 11편의 논문에서는 통계적 기법을 사용하지 않았다. 추론통계를 사용한 46편의논문에서 사용된 추론통계의 횟수는 각각 분할표분석 17회(37.0%), 비교통계분석 23회(50.0%), 회귀분석 7회(15.2%), 상관분석 5회(10.9%), 생존분석이 27회(58.7%)였다. 통계 기법을 활용하여 연구 결과를 분석할 때 통계적용의 오류가 없는 논문은 19%였다. ‘생략의 잘못’은 34편(50.0%)의 논문에서 총 50회 관찰되었다. ‘시행의 잘못’은 35편(51.5%)의 논문에서 총 47회 관찰되었다. ‘생략의 잘못’과 ‘시행의 잘못’이 모두 발견된 논문은 21편 (30.9%)이었다.결 론: 대한방사선종양학회지에 게재된 논문에서 통계 분석 과정의 다양한 영역에 걸쳐 크고 작은 통계적 오류가 있음을 확인하였다. 향후 대한방사선종양학회지 투고 논문의 심사 과정에서 통계 오류에 관한 적절한 심사를 추가하는 것이 필요하다고 판단된다. Purpose: To improve the quality of the statistical analysis of papers published in the Journal of the Korean Society for Therapeutic Radiology and Oncology (JKOSTRO) by evaluating commonly encountered errors. Materials and Methods: Papers published in the JKOSTRO from January 2006 to December 2007 were reviewed for methodological and statistical validity using a modified version of Ahn’s checklist. A statistician reviewed individual papers and evaluated the list items in the checklist for each paper. To avoid the potential assessment error by the statistician who lacks expertise in the field of radiation oncology; the editorial board of the JKOSTRO reviewed each checklist for individual articles. A frequency analysis of the list items was performed using SAS (version 9.0, SAS Institute, NC, USA) software. Results: A total of 73 papers including 5 case reports and 68 original articles were reviewed. Inferential statistics was used in 46 papers. The most commonly adopted statistical methodology was a survival analysis (58.7%). Only 19% of papers were free of statistical errors. Errors of omission were encountered in 34 (50.0%) papers. Errors of commission were encountered in 35 (51.5%) papers. Twenty-one papers (30.9%) had both errors of omission and commission. Conclusion: A variety of statistical errors were encountered in papers published in the JKOSTRO. The current study suggests that a more thorough review of the statistical analysis is needed for manuscripts submitted in the JKOSTRO.

벼 재배기간중 전남동부지역 농촌하천의 수질과 분포초종

이도진,조주식,국용인,안호근 한국환경농학회 2003 한국환경농학회지 Vol.22 No.1

전남 동부권에 위치하는 농경지 주변 4개 하천에 대하여 벼 재배기간을 전후한 시기에 하천수질의 특성과 분포하는 초종을 조사한 결과는 다음과 같다. 하천수질 특성은 다양하였으며 조사기간중 각 하천수의 pH는 6.5~8.3 범위였고, EC는 벌교천(162~4,910 μS/cm)에서 가장 높았으며 보성천(114.7~286.6 μS/cm), 송광천(74.8~147.4 μS/cm), 이사천(61.6~82.1 μS/cm)순이었다. 조사기간중 총질소 함량은 보성천(1.9~7.4 mg/L), 벌교천(2.1~3.9 mg/L), 송광천(2.4~3.4 mg/L), 이사천(1.7~2.6 mg/L)순으로 호소수질 환경기준 1등급(0.2 mg/L)과 농업용수 수질기준(1 mg/L)을 모두 초과하였다. 그 밖의 대부분 조사항목(K, Ca, Mg, Na, Cl^- 등)은 하천에 따른 함유량 고저 차이는 있었으나 모내기를 전후한 시기에 영양염류 함량이 가장 높게 나타나 보성천에서는 5월, 송광천과 이사천에서는 6월이었다. 4개 하천의 조사지점에서 관찰된 초종수는 모두 16과 30종이었으며 송광천, 보성천, 이사천, 벌교천에서 각각 18종, 19종, 15종 및 5종으로서 다년생은 17종, 일년생과 2년생은 13종이 출현하였다. 침수성 초종은 검정말, 말즘, 물수세미, 부유성 초종은 개구리밥과 좀개구리밥, 추수성 초종은 갈대, 고마리, 미나리, 여뀌, 줄 등이 관찰되었다. 물가와 주변에서는 개구리자리, 개피, 달뿌리풀, 돌소리쟁이, 물억새, 미국가막사리, 바늘골, 방동바니대가리, 뱀딸기, 사마귀풀, 삿갓사초, 살갈퀴, 선피막이, 소리쟁이, 쇠방동사니, 여뀌바늘, 큰도꼬마리, 토끼풀, 환삼덩쿨, 황새냉이 등의 20종이 관찰되었으며 그 중 고마리, 소리쟁이, 환삼덩쿨은 하천의 모든 조사지점에 출현하였다. The characteristic of the quality of stream water and the nlparlan vegetation during rice cultivation in the rural area of the eastern Jeonnam province was surveyed from April to November, 2000. The water quality of the streams during rice cultivation was variable. The pH of these water bodies ranged from 6.5~83. Electro conductivity (EC) at each water body ranged from 162~4,910 μS/cm for Beolgyo-cheon, 114.7~286.6 μS/cm for Boseong-cheon, 74.8~147 μS/cm for heon, and 61.6~82.1 μS/cm for Isa-cheon. Total nitrogen and other parameters (K, Ca, Mg, Na, CT, SS) were higher at May (Boseong-cheon) through June (Songgwang-cheon, Isa-cheon) during the transplanting season than these same parameters at August, October and November. Thirty weed species of sixteen families were found in the survey areas of Songgwang-cheon, Boseong-cheon, Isa-cheon and Beolgyo-cheon. Nine annual weeds, four biennial weeds, and seventeen perennial weeds were found, several different life forms were identified. Of those species three were submerged, two were free floating, five were emerged, and twenty were water-side weeds.

A New Quantitative Analysis of Phosphates by $^{31}P-NMR\;Spectroscopy^{1}$

Ahn Tae-Ho,Kang Ho-Cheol,Lee Sueg-Geun Korean Chemical Society 1992 Bulletin of the Korean Chemical Society Vol.13 No.6

Fluorination of Metals and Metal Oxides by Gas-Solid Reaction

Ho Geun Ahn,Eung Ho Kim,Byung Gil Ahn,Jae Hyung Yoo,Sang Woon Kwon 한국공업화학회 2002 Journal of Industrial and Engineering Chemistry Vol.8 No.5