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Tae-Il Um,Min-Young Kim,Tae-Eun Kim,Ik-Hwan Um 대한화학회 2014 Bulletin of the Korean Chemical Society Vol.35 No.2
Second-order rate constants for aminolysis of 2-chloro-4-nitrophenyl X-substituted-benzoates (1a-h) have been measured spectrophotometrically in 80 mol % H 2 O/20 mol % DMSO at 25.0 ℃. The Brønsted-type plot for the reactions of 2-chloro-4-nitrophenyl benzoate (1d) with a series of primary amines curves downward, which has been taken as evidence for a stepwise mechanism with a change in rate-determining step (RDS). The Hammett plots for the reactions of 1a-h with hydrazine and glycylglycine are nonlinear while the Yukawa- Tsuno plots exhibit excellent linearity with ρχ = 1.22-1.35 and r = 0.57-0.59, indicating that the nonlinear Hammett plots are not due to a change in RDS but are caused by stabilization of substrates possessing an electron-donating group (EDG) through resonance interactions between the EDG and C=O bond of the substrates. The α-effect exhibited by hydrazine increases as the substituent X changes from a strong EDG to a strong electron-withdrawing group (EWG). It has been concluded that destabilization of hydrazine through the electronic repulsion between the adjacent nonbonding electrons is not solely responsible for the substituent dependent α-effect but stabilization of the transition state is also a plausible origin of the α-effect.
Um, Tae-Il,Kim, Min-Young,Kim, Tae-Eun,Um, Ik-Hwan Korean Chemical Society 2014 Bulletin of the Korean Chemical Society Vol.35 No.2
The ${\alpha}$-Effect; Ground state; Transition state; Intramolecular H-bonding; Yukawa-Tsuno plot; Second-order rate constants for aminolysis of 2-chloro-4-nitrophenyl X-substituted-benzoates (1a-h) have been measured spectrophotometrically in 80 mol % $H_2O/20$ mol % DMSO at $25.0^{\circ}C$. The Br${\emptyset}$nsted-type plot for the reactions of 2-chloro-4-nitrophenyl benzoate (1d) with a series of primary amines curves downward, which has been taken as evidence for a stepwise mechanism with a change in rate-determining step (RDS). The Hammett plots for the reactions of 1a-h with hydrazine and glycylglycine are nonlinear while the Yukawa-Tsuno plots exhibit excellent linearity with ${\rho}_X=1.22-1.35$ and ${\gamma}= 0.57-0.59$, indicating that the nonlinear Hammett plots are not due to a change in RDS but are caused by stabilization of substrates possessing an electron-donating group (EDG) through resonance interactions between the EDG and C=O bond of the substrates. The ${\alpha}$-effect exhibited by hydrazine increases as the substituent X changes from a strong EDG to a strong electron-withdrawing group (EWG). It has been concluded that destabilization of hydrazine through the electronic repulsion between the adjacent nonbonding electrons is not solely responsible for the substituent dependent ${\alpha}$-effect but stabilization of the transition state is also a plausible origin of the ${\alpha}$-effect.
Um, Jang Il,Seo, Tae Young 부산대학교 1982 자연과학논문집 Vol.34 No.-
Bloch 函數空間 B(D)의 最大部分空間 B_(0)(D)가 Hornich operations을 가진 解析函數의 Banach 空間 H(D)에 isomorphic이고 Flett의 函數空間의 最大部分空間이 또한 H(D)에 isomorphic임을 보였고, 그리고 Hornich 空間에서 하나의 Representation Theorem을 얻었다.
고려엉겅퀴와 큰엉겅퀴의 모상근 유도 및 methyl jasmonate 처리에 따른 HPLC 패턴 변화
Tae Gyu Yi,Jong Dai Son,Yeri Park,Byung Hun Um,Nam Il Park 한국약용작물학회 2017 한국약용작물학술대회 발표집 Vol.2017 No.05
Background : Cirsium plants have been used for perennial edible plants and grow wild in the mountainous regions of Korea, including Cirsium setidens and C. pendulum. In particular, C. setidens is commonly called 'gondre', and it has been used medicinally for diseases such as hematuria, hepatitis and hypertension. Hairy roots cultivation can be used as a method for increasing production through mass culture of medicinal plants, and elicitors such as methyl jasmonate (MeJa) can be treated to increase the content of certain useful ingredients. In this study, the hairy root was derived from the leaf tissues of C. setidens and C. pendulum, and the HPLC pattern was compared by MeJa treatment. Methods and Results : Agrobacterium rhizogenes R1000 was used to induce hairy roots in 1/2× MS medium. In addition, the hairy roots was treated with MeJa for different time (0, 1, 2, 5, 10, 24, 48, 72 h) and with various concentrations (0, 10, 50, 100, 200, 300 μM). The HPLC pattern changes were analyzed by on-line HPLC-ABTS. Four new peaks were observed in both Cirsium setidens and C. pendulum hairy roots, all of which showed antioxidant activity. In the case of C. pendulum, chlorogenic acid content was about 4 times higher than that of leaves. These peaks, including chlorogenic acid, were all affected by MeJa treatment. Conclusion : Four peaks were detected in the hairy roots of C. setidens and C. pendulum not in the leaves, and they were confirmed to be affected by the treatment of MeJa. It is necessary to clarify the structure through the subsequent compound separation.
Optimal dimension design of a hatch cover for lightening a bulk carrier
Um, Tae-Sub,Roh, Myung-Il The Society of Naval Architects of Korea 2015 International Journal of Naval Architecture and Oc Vol.7 No.2
According to the increase of the operating cost and material cost of a ship due to the change of international oil price, a demand for the lightening of the ship weight is being made from various parties such as shipping companies, ship owners, and shipyards. To satisfy such demand, many studies for a light ship are being made. As one of them, an optimal design method of an existing hull structure, that is, a method for lightening the ship weight based on the optimization technique was proposed in this study. For this, we selected a hatch cover of a bulk carrier as an optimization target and formulated an optimization problem in order to determine optimal principal dimensions of the hatch cover for lightening the bulk carrier. Some dimensions representing the shape of the hatch cover were selected as design variables and some design considerations related to the maximum stress, maximum deflection, and geometry of the hatch cover were selected as constraints. In addition, the minimization of the weight of the hatch cover was selected as an objective function. To solve this optimization problem, we developed an optimization program based on the Sequential Quadratic Programming (SQP) using C++ programming language. To evaluate the applicability of the developed program, it was applied to a problem for finding optimal principal dimensions of the hatch cover of a deadweight 180,000 ton bulk carrier. The result shows that the developed program can decrease the hatch cover's weight by about 8.5%. Thus, this study will be able to contribute to make energy saving and environment-friendly ship in shipyard.
최일수 ( Il Soo Choi ),오종우 ( Jong-woo Oh ),엄태언 ( Tae-un Um ),이동훈 ( Donghoon Lee ) 한국농업기계학회 2017 한국농업기계학회 학술발표논문집 Vol.22 No.1
농산물의 품질 및 성분을 측정하는데 있어 기존의 화학적 분석 방식은 정밀도가 높으나 측정에 소요되는 시간과 비용이 많이 들어, 현장 적용하기에는 한계가 있다. 일반적으로 근적외선 분광 분석(Near InfraRed Spectroscopy, NIRS) 방법은 가공 과정에 따라 빠르게 변화되는 단백질 조성 및 수분함량 측정 등에 이용되고 있다. 분석에 소요 시간이 많이 걸리는 켈달법(Kjeldahi method)에 비해 NIR 분광 분석을 통한 보정으로 연속적인 모니터링이 가능하다. 본 연구에서 사용된 시료를 고정시키기 위한 프레임을 제작한후 NIR센서와 광원인 LED의 각도를 고정시키고 측정 대상체인 사절된 감자 크기에 따라 시료를 고정시킬 수 있는 프레임을 반사면에 위치시켰다. 확산 반사법을 이용하여 프레임에 씨감자 시료를 고정 시킨후 백색 LED를 이용하여 감자 표면에 빛을 반사시켜 3일 동안 12시간 마다 해당 시료들(열처리, 비누용액 침지, 생감자)의 스펙트럼을 측정하였다. 해당 시료들은 측정 기간 동안 저온상태(4℃)와 실온상태(20℃)에서 보관되었다. 실험 결과는 파장대 145nm에서 저온상태에서 보관된 생감자는 시간경과에 따른 흡광도의 결정 계수값(r2)은 0.98 이었다. 이는 감자가 저온에서 생감자의 상태 변화가 일어나고 있다는것을 의미하고 파장대 145nm에서 시간에 따른 저온상태에서 보관한 감자의 상태 변화 예측이 가능함을 의미한다. 비누용액에 침지시킨 후 실온에 보관한 감자는 시간이 경과함에 따라 파장이 증가함에 따라 흡광도가 증가하였다. 이는 감자에 들어있는 Polyphenol Oxidase 함량 변화로 갈변 현상이 일어난 것을 알 수 있다. 또한 실온에서 보관한 생감자도 시간 경과에 따라 갈변 현상이 일어났지만 용액에 침지시킨 감자보다는 갈변 현상이 36시간 이후로 발견되었다. 열처리 후 실온에서 보관한 감자의 경우에는 갈변현상이 나타나지 않았다. 저온상태에서 보관한 감자시료들 모두 갈변형상이 나타나지 않았지만, 24시간이 지난 후 용액에 침지시킨 감자는 갈변 현상이 발생되었다. 생감자와 열처리한 감자는 시간 경과에 따른 갈변현상이 일어나지 않았으므로, 감자의 갈변현상은 감자의 표면 처리 방법에 국한되지 않고 온도에 영향을 더 많이 받는다는 것을 나타내고 있다. 본 연구는 향후 감자의 품질 및 성분 측정에서 간편하게 사용될 수 있는 감자의 품질 계측 기술에 기여할 것으로 판단된다.