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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, ??.
수처리 부산물로 생성되는 염소산화물의 효율적 제거에 관한 연구
성대동,이성식 동아대학교 환경문제연구소 1999 硏究報告 Vol.22 No.1
The photodegradation efficiency of chlorine oxides in the drinking water has been studied by means of laser flash photolysis. The results are summarized as follows ; A high amount of ClO is produced just at the irradiation of laser flash. The absorption spectrum of ClO shows strong on the spectrophotometric measurement. The efficiency of removal of ClxOy reveals about 60~70% within 2㎲ after laser flash irradiation. The removal efficiency is decreased with the increase of the water thickness from 40㎝ to 80㎝ and also the efficiency is decreased about 4~6%. The removal rate of Cl₂O_(7) shows 3 times higher than one of Cl₂O_(6).
성대동,박유미 동아대학교 환경문제연구소 1993 硏究報告 Vol.16 No.1
The reaction mechanism and molecular carcinogenetic property for the reaction of Seyferth's reagents such as phenyl(bromodichloromethyl)mercury and phenyl(tribromomethyl) mercury with food additives as dehydroacetic acid and coumarin has been studied under the conditions fo UV/vis photolysis and laser flash photolysis. 1. The reaction reactivities of Seyferth's regents as phenyl(bromodichloromethy1)mercury and phenyl(tribromomethyl) mercury are compared in all reaction conditions. The reactivity of phenyl(bromodichloromethy1) mercury is higher than the reactivity of phenyl(tribomomethy1) mercury at any reaction conditions in this research. This means that the leaving effect of : CCl₂carbene is higher than that of CBr₂carbene from mercury atom in Seyferth's reagent. 2. The yield of a highly toxic carcinogenetic carbene intermediate in the condition of UV/vis photolysis is less than those of laser flash photolysis. It is explainable that the reactions of Seyferth's reagent with the food additives are inhibited compared with the dimerization reaction of dihalogen carbenes each other. 3. The reactions of Seyferth' s reagents with dehydroacetic acid and coumarin are accelerated increasing with the negative(-) values of the bond energy of HgCCX₂and σ MO energy.
성정훈,강대원,이윤수,임준우,홍영호,이덕동 경북대학교 센서기술연구소 1998 센서技術學術大會論文集 Vol.9 No.1
High selective and sensitive thick film type methane gas sensors were fabricated and their sensing characteristics for various hydrocarbon gases were investigated. Raw material, SnO_(2)/Au, prepared by coprecipitation was even grain size. SEM, TEM, BET and XRD analyses were carried out for investigation of surface morphology and crystalline structure. The thick film devices using the above materials exhibited high sensitivity to methane gas at the operating temperature of 400°C. The sensitivity of SnO_(2)/Au+Pd thick film devices to methane gas was higher than that to the other hydrocarbon gases such as iso-butane and propane. The optimal adding amounts of Au and Pd were 1wt.% and 3wt.%, respectively. The sensitivity, S, is defined as {(R_(A)-R_(G))/R_(A)}><100, which R_(A) and R_(G) are resistance in air and that in the gas ambient, respectively.
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.