• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 2000년도 춘계학술대회
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• pp.6-7
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• 2000

Recently, free radicals such as active oxygen species, nitric oxide, etc are believed to be one of the key substances in physiological and pathological, toxicological phenomena, and oxidative damages, and all organism have defencing system against such as free radicals. Formation and extinction of free radicals may be regulated through bio-redox system, in which various enzymes and compounds should be involved in very complicated manner. Thus, direct and non-invasive measurement of in vivo free radical reactions with living animals must be essential to understand the role of free radicals in pathophysiological phenomena. Electron spin resonance spectroscopy (ESR) is very selective and sensitive technique to detect free radicals, but a conventional ESR spectrometer has large detect in application to living animals, since high frequent microwave is absorbed with water, resulting in generation of high fever in living body. In order to estimate in vivo free radical reactions in living whole animals, we develop in vivo ESR-CT technique using nitroxide radicals as spin probes. Nitroxide radicals and their reduced forms, hydroxylamines, are known to interact with various redox systems. We found that! ! the signal decay due to reduction of nitroxyl radicals is influenced by aging, inspired oxygen concentration, ischemia-referfusion injury, radiation, etc. In the present paper, I will introduce in vivo ESR technique and my laboratory recent results concerning non-invasive evaluation of free radical reactions in living mice.

• 대한건축학회논문집:계획계
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• 제35권4호
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• pp.127-134
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• 2019

Recently, the city development policies are being switched to the policies focusing on recession worldwide. Even though South Korea is also facing the phenomena that small and medium-sized cities are downsized because of a decrease in population and an aging society problem, there is lack of solutions and even they are still planning city development policies based on prospect of high growth. This study is featuring 4 viewpoints depending on shrinking population trend in 7 small and medium sized local cities, which are chosen as downsized cities. It is dealing with population peak, current population, 2030 population, and 2040 population viewpoints. And this study uses downsizing simulation that suggests optimum area that fits population and then shows visual check of the status of the small and medium sized local cities. The area of the small and medium sized local cities are expanded more than needs when they are on population peak point. However, they need only 20% to 25% of current area in 2030 and 2040. The most important thing is realizing the seriousness and facing up to the 'shrinking' phenomena that each small and medium-sized cities suffer. Therefore, this study has significance for presenting the status of small and medium-sized cities' problems in South Korea.

• 공업화학
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• 제17권4호
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• pp.386-390
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• 2006

콜로이드형 실리카는 화학적으로 안정한 무기소재로 비표면적과 표면물성이 우수하여 산업적으로 다양한 용도로 사용하고 있다. 본 연구에서는 sodium silicate로부터 이온교환방법 및 산-중화법을 이용하여 colloidal silica를 제조하고 입자성장인자인 온도, pH, 농도와 aging time을 조절하여 크기를 조정하는 방법을 조사하여 균일한 크기분포를 가진 colloidal silica를 제조하였다. 실리카 졸의 크기와 모양은 TEM 및 dynamic scattering method를 이용하여 측정하였다. 또한 콜로이드의 입자크기에 따른 제타 전위값의 변화, 겔화현상과 그 유변학적 특성을 연구하였다.

• 한국연초학회지
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• 제13권1호
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• pp.61-68
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• 1991

The moisture contents of threshed leaf tobacco during aging storage were very important factor for the improvement or deterioration of leaf quality. Decay and carbonization of leaf tobacco were mainly controlled by moisture contents during storage. The influence of moisture contents on the decay and carbonization of threshed leaf tobacco (Flue-Cured, Var. NC 82. AB3O-1 grade) were examined during 1 year. The moisture contents of leaf tobacco were treated to 3 kg as 12% (controle), 16%, 20% and 24% after redrying, respectively, These tobacco were put into center of carton box containing about 200kg with 12%'s tobacco, and then packed and stored from June, 1988 under natural weather condition in warehouse at Ock-Cheon threshing plant. Samples were taken from dissected carton box at 0, 1, 2, 4, 7 and 12 months after moisture treatment and Racking time, and some chemical properties were investigated at every sampling time. In results of inducement to decay and carbonization of leaf tobaccos during 1 year's storage by moisture treatment. decayed leaf was appeared but carbonized leaf did not. Calorification and decayed leaf occurred at high moisture contents above 20%, and these phenomena were appeared between 30 and 150 days after moisture treatment and packing. High moisture content leaves (above 20%) caused nearby other leaves to be sunk with high moisture content. Nicotine and calcium contents were increased to 20%~30% and 10%~22%, respectively, but total sugar contents was decreased to 40%~60% by moisture treatment(20% ~24% ).

• Journal of Electrical Engineering and information Science
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• 제2권3호
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• pp.71-76
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• 1997

A lot of experiments and analyses have been done to determine the aging mechanism of mica-epoxy composite material used for large generator stator windings in order to estimate remaining life of the generator for last decades. After degrading artificially the mica-epoxy composite material, the surface analysis is performed to analyze breakdown mechanism of insulation in air and hydrogen atmosphere; i) In the case of air atmosphere, it is observed that an aging propagation from conductor to core by partial discharge effect and the formation of cracks between layers is widely carbonized surface. ii) In case of hydrogen atmosphere, the partial discharge effect is reduced by the hydrogen pressure (4kg/$\textrm{cm}^2$). Potassium ions forming a sheet of mica is replaced by hydrogen ions, which can lead to microcracks. It is confirmed that the sizes of crack by SEM analysis are 10∼20[$\mu\textrm{m}$] in length under air, and 1∼5[$\mu\textrm{m}$] in diameter, 10∼50[$\mu\textrm{m}$] in length under hydrogen atmosphere respectively. The breakdown mechanism of sttor winding insulation materials which are composed of mica-epoxy is analyzed by the component of materials with EDS, SEM techniques. We concluded that the postassium ions of mica components are replaced by H\ulcorner, H$_3$O\ulcorner at boundary area of mica-epoxy and/or mica-mica. It is proposed that through these phenomena, the conductive layers of potassium enable creation of voids and cracks due to thermal, mechanical, electrical and environmental stresses.

• 한국압력기기공학회 논문집
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• 제7권3호
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• pp.23-29
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• 2011

The renewed global interest in nuclear power has arisen from the need to reduce greenhouse gas emissions and to provide sufficient electricity for a growing global population before the accident at Fukushima Dai-ichi nuclear power plant in Japan. In spite of the safety issues of nuclear power plants raised by the ongoing Japanese nuclear crisis, many countries with nuclear power plants (NPPs) are still implementing license extensions of 10~20 years, and even consideration is being given to the concept of life-beyond-60, a further period of license extension from 60 to 80 years. To solving the materials aging problem is integral to its success. To evaluate the plant aging phenomena, a lot of background information such as materials and environment of the parts of the reactor and plant systems is needed by the experts. Information on degradation mechanisms is also used. In this paper, a materials degradation evaluation program called OnMDE-SYS (On-line Materials Degradation Evaluation System) is introduced. The developed program provides a variety of information on the materials and stressors as well as operational experience to the experts. It is also anticipated that the experts can perform materials degradation assessment on the web directly by referring to domestic and international information about the degradation of a nuclear power plants through OnMDE-SYS.

• 혜화의학회지
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• 제8권1호
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• pp.643-657
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• 1999

Through observing effect of BOPEASAN(BPT) on an aging white rat's metabolic enzyme system, the following conclusions were addressed 1. The quantity of the lipid peroxide in lung of was decreased meaningfully in all of experimental subject groups, relatively to counterpart groups. 2. Cytochrome P-450, Cytochrome b5, NADPH-Cytochrome P45, was decreased meaningfully in the experimental subject groups B,C and D. 3. superoxide dismutase, catarase, grutathione peroxidase, was increased meaningfully in the experimental subject groups B.C and D. 4. glutathione, glutathione S-transferase, glutathione redutase, ${\gamma}$-Glutamylcytein synthetase, had no meaningful change in the experimental subject groups. Regarding the above conclusions, the Bopeasan was affecting positively on both lipid peroxide a nd the enzyme system, as well as it has efficacy of suppressing the phenomena of aging, Therefore, the Bopeasan is, hereafter, expected to be applied clinically.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 센서 박막재료 반도체 세라믹
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• pp.219-222
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• 2003

$0.2(PbMg_{1/3}Nb_{2/3}O_3)-0.8(PbZr_{0.475}Ti_{0.525}O_3)$ 조성을 이용하여 $5{\times}5{\times}5mm^3$의 적층형 세라믹 액츄에이터 소자를 tape casting 방법으로 제작하였다. 전극재로서는 Ag-Pd를 이용하여 총 50층의 layer를 적층하였으며, 적층된 액츄에이터를 $1100^{\circ}C$의 온도에서 소결하였다. X-ray diffractometer를 이용하여 제작된 소자와 열화된 소자의 구조적인 특성을 분석하였다. 제작된 소자의 열화 특성을 알아보기 위하여 60 Hz 의 triangular wave를 인가하여 열화전과 후의 p-E hystcresis loop의 변화를 살펴보았으며, 인가된 전압의 변화에 따라서 소자에서 발생되는 양의 열을 측정하였다. 파괴된 소자의 파단면에 대한 SEM 분석을 통하여 소자의 파괴 메카니즘을 알아보도록 하였다. 이로부터 전기적 기계적 열화가 소자의 동작에 미치는 영향에 대해서 알아 보았다.

• 응용통계연구
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• 제31권5호
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• pp.637-653
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• 2018

빠른 고령화로 고령층의 증가는 인구구조 변화와 인구고령화에 영향을 미친다. 예전부터 선진국은 인구고령화를 주요현안으로 간주하여 고령화로 인한 연금 재정건전성, 건강 및 노인 복지 시스템의 지속 가능성에 집중하고 있다. 이처럼 고령층의 증가로 인구구조 변화와 인구고령화에 미치는 사망률 예측은 어느 때보다도 중요하다. 본 논문은 통계청 1970-2016년 각세별 생명표 자료를 활용하여 사망률 모형 6가지를 비교하였다. 이들 모형은 Lee-Carter(LC) 모형 (Lee and Carter, Journal of the American Statistical Association, 87, 659-671, 1992)에 근원을 두고 있으며, LC 의 가정을 수정하고 개선한 것이다. 이들 개선과정과 가정검토를 모형별로 살펴보고 우리나라에 적합한 사망률 모형을 모색했다. 분석결과 빠른 고령화와 연령별 사망률의 개선 효과를 보이는 우리나라의 경우 기대수명에 큰 변화를 주지 않고 이들 현상을 반영하고 연령별 사망률 패턴을 수정하는 LC-ER 모형 (Li 등, Demography, 50, 2037-2051, 2013)과 Li-Lee 모형과 LC-ER모형을 조합한 LL&LC-ER 모형으로 사망률을 예측하는 것이 바람직하다.

• 한국식품영양과학회지
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• 제24권5호
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• pp.796-802
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• 1995

본 연구에서는 전통적인 오이장아찌 담금 방법을 고찰하여 오이를 5종류의 침지액에 침지 후 고추장, 된장, 간장오이장아찌를 제조하면서 저장 숙성 중 오이장아찌의 경도와 칼슘 함량의 변화 및 효소활성(pectin esterase, polygalacturonase)변화를 측정하였다. 고추장오이장아찌의 경우 경도는 모든 처리구에서 저장 10일째 심화된 중공현상으로 가장 낮게 나타났으며 그 이후 경도가 증가흐는 것으로 나타났다. 된장 및 간장오이장아찌의 경우 모든 처리구에서 경도는 저장 숙성기간 중 약간씩 감소되는 것으로 나타났다. 오이를 5종류 침지액 48시간 침지한 후 오이헤 흡착된 Ca 이온의 농도는 소금물의 농도가 높을수록 Ca의 흡착 정도가 더 높게 나타났다. 침지 처리가 끝난 5종류의 처리구를 담금원(고추장, 된장, 간장)에 담금하여 숙성하면서 측정한 Ca 이온의 농도는 저장 숙성기간 중 모든 처리구에서 점차 증가하는 경향을 나타내었으며 그 이후는 3ㄷ가지 담금원의 Ca 농도가 70~120mg/100g으로 높았기 때문에 Ca 농도차에 의하여 담금원으로 부터 오이장아찌로 Ca이 이동하였기 때문으로 생각된다. PG 활성의 고추장, 된장, 간장오이장아찌의 숙성 중 일반적으로 감소되는 경향을 나타내었다. 고추장, 된장, 간장오이장아찌의 경우 PG 활성은 담금 5일째 급격히 감소하였으며 그 후 대개 일정한 수준을 유지하였다. 또한 고추장, 된장, 간장오이장아찌의 경우 PG의 효소활성은 12% 식염수에 처리한 오이(처리구 4~6)가 6% 식염수에 처리한 오이(처리구 2, 3) 보다 일반적으로 높게 나타났다. PE의 활성은 고추장, 된장 오이장아찌의 경우 일반적으로 저장 숙성 기간 중 점차 증가되었으나, 간장오이장아찌는 15일 까지 효소 활성도가 점차 증가되었으나 그 이후 PE의 활성도는 약간 감소된 후 일정 수준을 유지하였다.