[논문]Operational Characteristics of CO2 Laser Adopted by Superposing-Discharge

Hee-Je Kim,Hyun-Ju Chung,Byoung-Dae Min,Jong-Han Joung,Sung- lun Park 釜山大學校生産技術硏究所 2003 生産技術硏究所論文集 Vol.62 No.-

오늘날 현저한 CO2 레이저의 응용 추세에 발맞추어 보다 다양한 형태의 출력 제어 기술이 대두되고 있다. 본연구에서는multi-Pulse Superposing-Discharge 기술을 이용하여 다양한형태의 CO2 레이저의 펄스를 성형 하였다. 펄스 성형을 위한 방법으로 PIC one-chip microprocessor를 이용하여 삼중 PFN 모률의 SCR을 각각 고유의 지연시간을 가지도록 제어하였다. 실험에 사용된 삼중 PFN 모률의 전원 회로는 각각 캐패시터 인덕터,SCR,고압 펄스 트랜스 그리고 고압 트랜스 2차측에 브릿지 정류기로 구성 하였다. 고압 펼스 트랜스의 1차측을 제어하므로서 PFN 모률의 동작을 저 전압에서 수행 할 수 있다. 트랜스의 2차측에 연결된 전파 정류기는 펄스 에너지를 부하에 지속적으로 전달한다. 본 연구에서는 삼중 PFN 모률의 각각의 SCR을 다른 시간 가격을 두고 트리거 하므로서 다양한 Long pulse shaping을 실현하였다. 또한 약 250-1000μs 의 주기를 가지는 다양한 펄스형 레이저 빔을 얻었다.

품종 및 성별에 따른 쇠고기의 지방산조성 비교

김대곤,성삼경,정근기,최창본 대구산업정보대학 1995 논문집 Vol.9 No.2

Dae Gon The study was conducted to investigate the effect of breed, sex on fatty acid compostition. Hanwoo and Holstein used, in the study were classified by sex. The results are summarized as follows ; Oleic acid and unsaturated fatty acids(UFA) percentages of total fatty acids in Hanwoo were higher than in Holstein, but palmitic acid and saturated fatty acids(SFA) were lower in Hanwoo. Oleic acid in steers of Hanwoo and Holstein tended to increase compared with bulls. Oleic acid in rib loin and top round were considerably higher in Hanwoo steers than in Holstein steers. In Hanwoosteers, oleic acid and UFA tended to increased while stearic acid and SFA decreased as marbling degree increased.

親核性 置換反應에서 最大速度現象과 Hammett 相關關係

성대동,이종팔,이미정,엄태섭 東亞大學校 大學院 1996 大學院論文集 Vol.21 No.-

The nucleophilic substitution reactions of p-substituted benyl bromide with p-substituted N,N-dimethyl anilines in methanol and acetonitrile binary solvent mixtures which are known as an isodielectric olvent system kinetically and the results are as follows. 1.The postive dharge is developed on the reaction center of the substrate and it means that the bond cleavage is preceded more than bond formation in the transition on the analogy of Hammett ?? values. 2.The bond formation is not progressed in the case of electron donating substituent of substrate. however, the bond formation is much developed in the case of electron withdrawing substituent of substrate on the anlogy of Hammett ?? values. 3.The nucleophilic attacking ability is shown a highest at 80%(V/V) methanol content and the bond formation is well progressed at the same methanol composition on the result of a cross interacton coefficient, ??.

근위부 후하소뇌동맥의 자연박리성 동맥류 1예

구본대,이종호,김상범,이계훈,허경,이병희 대한신경과학회 1999 대한신경과학회지 Vol.17 No.5

개선된 교통 신호 제어시스템 설계에 관한 연구

김대성,허광선,권민수,곽동호,원충상 忠州大學校 2010 한국교통대학교 논문집 Vol.45 No.-

There are various ways to operate traffic light system by varying the operational speed of the system. One of the solutions is to vary the length of the clock cycle of the system. It is difficult to vary the length of the signal in systems by varying the period of the clock cycle and nor it is a generalized technology in the current traffic systems. The traffic signal systems of the past used is simply a repetitive traffic signal system which traffic period is consistent, not considering the conditions of traffics. The system that will be introduced in this thesis could substantially improve efficiency of traffic flows by varying the length of traffic signal period with sensors which detect the presence of vehicles on both directions and allows the signal continuously on the direction where there are more waiting vehicles, and even skips the signal where there is no vehicle waiting. In this thesis, it introduces the methodology of detecting the spots that is detected by the sensors of the system and outputs green light in due order in accordance with the priority given to the system. In the meanwhile, the ratio of yellow light and green light is designed to be 1 to 8 in the way that maximizes the efficiency of traffic flows.

염화나프토일의 親核性置換反應에 미치는 溶媒效果

成大東 東亞大學校 1980 東亞論叢 Vol.17 No.2

1-염화나프토일과 2-염화나프토일의 가매분해반응을 에탄올-아세토니트릴, 2-프로판올-아세토니트릴, 에탄올-아세톤, 2-프로판올-아세톤, 에탄올-물, 2-프로판올-물, 3차 부탄올-물 혼합용매 속에서 전기전도도법으로 측정하였다. 혼합용매의 조성에 관계없이 1-염화나프토일이 2-염화나프토일보다 속도가 크게 나타났다. 이것은 Dewar지수 Nr과 Streiwiesr의 σ+값과도 일치하였다. 1-염화나프토일은 Sn2전이상태에서 반응중심탄소가 sp²에서 sp³로 변하므로 peri-hydrogen effect가 relieve 됨을 알 수 있었으며 또한 모든 반응이 대체로 Sn2 반응메카니즘으로 진행됨을 알 수 있었다. 동일한 반응기질이 에탄올과 2-프로판올 및 공용매인 아세토니트릴의 혼합용매속에서도 메탄올-아세토니트릴 혼합용매에서와 같은 최대속도 현상이 나타났다. 즉 메탄올-아세토니트릴 혼합용매게에서는 메탄올의 물분율 0.85에서 최대치가 나타나는데 비해 등유전성이 아닌 에탄올-아세토니트릴 혼합용매게에서는 에탄올의 물분율 0.78에서 2-프로판올-아세토니트릴 혼합용매계에서는 2-프로판올도의 물분율 0.62에서 각각 최대속도상수를 갖는다. 이것으로 미루어 볼 때 에탄올과 2-프로판올도 메탄올과 같이 수소결합을 형성하여 다량체를 만들고, 가용매분해반응에서 아세토니트릴이 첨가될 때 이들 알코올의 다량체 구조가 파괴됨을 알 수 있었다. 또한 섭동분자이론(PMO)에서 구한 비결합분자궤도함수(NBMO)의 계수와 반응속도의 대수가 거의 직선적으로 비례함을 알 수 있었다. The kinetics for solvolysis of 1-naphthoyl and 2-naphthoyl chlorides have been measured in solvent mixtures, EtOH-Me추, 2-PrOH-MeCN, EtOH-(Me)₂CO, 2-PrOH-Me)₂CO, EtOH-H₂O, 2-PrOH-H₂O and t-BuOH-H₂O. The rate constants of 1-naphthoyl chloride were faster than 2-naphthoyl chloride in all solvent mixtures. This agrees with Dewar number, Nr and Streitwieser's σ+ value. It was concluded that the valence state of carbonyl carbon changed from sp² to sp³ in transition state and peri-hydrogen effect was relieved; the solvolytic reactions proceeded by Sn2 mechanism in all solvent mixtures system. There were maxima in rate of reaction for EtOH-MeCN, 2-PrOH-MeCN mixtures in the same way as for MeOH-MeCN mixture. The maximum rate in EtOH-MeCN mixture was observed at mole fraction of EtOH, 0.85 and in 2-PrOH-MeCN mixture was observed at mole fraction of 2-PrOH, 0.62. This behavior is interpreted as the structure of alcohols also has hydrogen bonding structure, and the polymer structure of alcohols is destroyed by adding aprotic solvent, MeCN. Comparing the perturbation molecular orbital theory in the transition state, the logarithms of solvolytic rate constants have been found to be proportional to the AO coefficient of nonbonding molecular orbital, 2a? in this solvolytic reaction.

Dabsyl Chlorides의 親核性 置換反應

成大東,朴現錫,柳俊夏,金良姬,李鍾八,嚴泰燮 東亞大學校 1990 東亞論叢 Vol.27 No.1

Kinetic studies of nuclsophilic substitution reaction of dabsyl chloride with pyridines have been investigated at 30℃ in a range of methanol-acetonitrile bianary solvent mixtures. The order of magnitude fo reactivity is β-picoline > pyridine > 1.5-N D A > α-picoline to react with dabsyl chloride, especially in case of α-picoline, the reactivity revealed lower than others, it is suggestd that nitrogen atom of pyfidine ring has a steric hinderance by the neightboring methyl group. The value of ρ(-0.96∼4.59) and β(0.36∼0.67) associated with a change of substituent in the nucleophile are large and indicate a realtively advanced bond formation in the transition state. Solvatochraomic correlations were predicted the importance of bond formation transition state, showing a greater contribution of polaritypolarizability (π*) lone paired to hydro-gen bond donar acidity (α). We conclude that the reaction of dabsyl chloride with pyridine proceed via S2 type reaction mechanism, as well as the reaction of dansyl chloride pyridine.

Oxametallaborane 및 Metallacarborane과 Phenyl Carbene 반응에 대한 반응성과 반응메카니즘

성대동,이용희,심경옥 동아대학교 기초과학연구소 2000 基礎科學硏究論文集 Vol.17 No.1

거대고리 뭉치 붕소화합물 중 산소원자를 포함하는 oxametallaborane과 탄소원자를 포함하는 metallacaborane을 이용하여 새로운 metallacarborane을 합성할 수 있는 방법을 알아보고 [9,9-(PMe2Ph)2-arachno-9,6-PtOB8H10]과 [9,9-(PMe2Ph)2-arachno-9,6-PtOB8H12]를 합성한 후 이들에 phenyl diazomethane을 반응시켰다. [9,9-(PMe2Ph)2-arachno-9,6-PtOB8H10]과 phenyl diazomethane의 반응생성물은 예상과는 달리 cis-및 trans-stilbene과 trans, trans-benzaldehyde azine이었다. 카르벤의 이량화 반응은 [9,9-(PMe2Ph)2-arachno-9,6-PtOB8H10]의 촉매 작용에 의해 촉진 되었다. Oxametallaborane의 Pt-원자에 있는 d-오비탈이 카르벤의 삼중항 상태의 T1과 T2전자상태를 안정화 시켰다. [9,9-(PMe2Ph)2-arachno-9,6-PtOB8H12]와 phenyl diazomethane의 반응생성 oxametallaborane의 결과와 유사하였고 동시에 미량의 C-카르벤 삽입 반응생성물이 생성되었다. Metallacaborane의 탄소 원자궤도함수인 SOMO와 phenyl diazomethane의 LUMO가 반응하여 분자궤도함수 에너지를 낮추는데 기여하였다. The reaction mechanism and a new synthetic method using oxametallaborane and metallacarborane compounds are investigated. [9,9-(PMe2Ph)2-arachno-9,6-PtOB8H10] and [9,9-(PMe2Ph)2-arachno-9,6-PtCB8H12] are synthesized then, reacted with phenyl diazomethane to find out a new synthetic method corresponding to the metallacarborane cage compound. Unexpectedly cis- and trans-stilbene and trans, trans-benzaldehyde azine are produced from the reaction of [9,9-(PMe2Ph)2-arachno-9,6-PtOB8H10] with phenyl diazomethane. [9,9-(PMe2Ph)2-arachno-9,6-PtOB8H10] is operated as a kind of catalyst to yield dimerization product of carbene. The d-orbital in Pt-atom of oxametallaborane stabilizes the two triplet states of carbene, T1 and T2. A similar reaction products are produced from the reaction of [9,9-(PMe2Ph)2-arachno-9,6-PtOB8H12] with phenyl diazomethane and a trace amount of a new product is also produced such as C-carbene insertion reaction product simultaneously. The molecular orbital energy is lowered by the SOMO energy of metallacarborane and the LUMO energy of phenyl carbene.

복부기형혈관의 문맥-체순환 단락으로 유발된 만성 후천성 간뇌 퇴행중 1례

김대현,김종국,차재관,김상호,김재우 대한신경과학회 1998 대한신경과학회지 Vol.16 No.2

대장 및 직장암 환자에서 DNA Ploidy 및 증식능과 기존의 예후인자와의 상관관계 분석

김상철,김대성,노병선,윤광수 대한대장항문학회 1996 Annals of Coloproctolgy Vol.12 No.1