http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
1치환 벤즈알데히드의 첨가-탈수반응에서의 pH 및 치환기 효과
金容仁 弘益大學校 1986 弘大論叢 Vol.18 No.2
pH dependence and the effect of substisuents on the addition-dehydration of 7 monosubstitude benzaldehydes have been studied in buffered 25% methanol aqueous solution at 25℃. It was found that the reaction below pH 3 and around pH 4~7 procceeded rapidly according to the decrease of pH value but proceeded nearly constantly at the range of pH 3~4. Good linear free-energy relationships have been observed for the reactions at pH 2.57 and 7.05, not at pH 3.35 and 4.87, and the calculated reaction constants from Hammett plots are +0.66 and +0.04 at pH 2.57 and 7.05, respectively. The change between the rate-determing addition and dehydration was found around pH 3~4 by the influence of pH value, the substituent effect and acid catalyst-concentration.
김용인,류지호,민문기,박맹렬,박순창,염석란,한상균,박성욱,이성화 대한응급의학회 2018 Clinical and Experimental Emergency Medicine Vol.5 No.2
Objective To assess whether ultrasonographic examination compared to chest radiography (CXR) is effective for evaluating complications after central venous catheterization. Methods We performed a prospective observational study. Immediately after central venous catheter insertion, we asked the radiologic department to perform a portable CXR scan. A junior and senior medical resident each performed ultrasonographic evaluation of the position of the catheter tip and complications such as pneumothorax and pleural effusion (hemothorax). We estimated the time required for ultrasound (US) and CXR. Results Compared to CXR, US could equivalently identify the catheter tip in the internal jugular or subclavian veins (P=1.000). Compared with CXR, US examinations conducted by junior residents could equivalently evaluate pneumothorax (P=1.000), while US examinations conducted by senior residents could also equivalently evaluate pneumothorax (P=0.557) and pleural effusion (P=0.337). The required time for US was shorter than that for CXR (P<0.001). Conclusion Compared to CXR, US could equivalently and more quickly identify complications such as pneumothorax or pleural effusion.
EXISTENCE OF PERIODIC SOLUTIONS FOR PLANAR HAMILTONIAN SYSTEMS AT RESONANCE
김용인 대한수학회 2011 대한수학회지 Vol.48 No.6
The existence of periodic solutions for the planar Hamilton-ian systems with positively homogeneous Hamiltonian is discussed. The asymptotic expansion of the Poincare map is calculated up to higher or-der and some sufficient conditions for the existence of periodic solutions are given in the case when the first order term of the Poincare map is identically zero.
EXISTENCE OF PERIODIC SOLUTIONS FOR A GENERAL CLASS OF p-LAPLACIAN EQUATIONS
김용인 한국수학교육학회 2011 純粹 및 應用數學 Vol.18 No.1
The existence of T-periodic solutions for a general class of p-Laplacian equations is investigated. By using coincidence degree theory, some existence and uniqueness results, which generalize some earlier works on this topic, are presented.
SUFFICIENT CONDITIONS FOR THE INTERSECTION PROPERTY IN GENERALIZED LI¶ENARD SYSTEMS
김용인 한국수학교육학회 2011 純粹 및 應用數學 Vol.18 No.3
Some new results on the intersection property of all nonzero solutions of a class of planar systems of Li¶enard type with vertical isoclines are obtained. The results of this paper generalize some previous results on this ¯eld.
N,N-Dimethylaniline의 아조커플링 반응에 關한 硏究
金容仁,明孝信 弘益大學校 1982 弘大論叢 Vol.14 No.2
The coupling reaction of N, N-dimethylaniline with several monosubstituted benzenediazonium salts has been studied kinetically in aqueous buffered solution. The activation evergies measured in the coupling reaction of N, N-dimethylaniliine with diazotized p-nitroaniline, m-nitroaniline, sulfanilic acid, m-anisidine,p-anisidine, p-bromoaniline, p-chloroaniline, m-toluidine, p-toluidine are 8.46, 8.05, 9.20, 12.32, 15.91, 10.86, 11.54, 13.80, 14.35, 15.47Kcal/mole, respectively. The coupling reactionis more favorable in the presence of an electron-withdrawing group in active components than in the presence of electron-donating group. It has been observed that the coupling reaction with diazotized p-nitroaniline proceeds 1000 times more rapidly than that with the benzenediazonium salt, which is coupled 40 times faster than diazotized p-anisidine. In our experiments, the formation of triazene, the diazoamino compound has not been observed, and the experimental result that the ionic strength of the medium didn't give any influence on the coupling reaction rate leads to the confirmation of the neutral free amine being one of the reasonable reactive species in the coupling reaction. A linear free energy relationship has been essentially observed except for three para substituted active components, for which the extended Hammett plot treated by Yukawa-Tsuno permits a good log k/k??=ρ(σ+ rㆍ????) linear relationship when considering the mesomeric effect. The calculated reaction constant of these azocoupling reaction is ρ=3.92, and the reaction constant of resonance contribution is calculated as r=0.32 at 20 ℃.