Citrate Process를 이용한 BaCeO₃ 나노 분말의 저온 합성

이동욱,원종한,주경,김창열,심광보,Lee, Dong-Wook,Won, Jong-Han,Joo, Kyoung,Kim, Chang-Yeoul,Shim, Kwang-Bo 한국세라믹학회 2002 한국세라믹학회지 Vol.39 No.6

Nanosized $BaCeO_3$ powders with the stoichiometric composition of a molecular level were synthesized by the citrate process based on the Pechini method. Polymeric precursor was formed by use of citric acid and ethylen glycol, as chelating agent of metal ions and reaction medium, respectively. Single phase orthorhombic structured $BaCeO_3$powders, about 100 nm sized and uniform shaped were obtained through the calcination of the polymeric precursor at $900^{\circ}C$ for 4 h. Extremely small quantities of carbonate ions($CO_^{2-}$) were completely decomposed at over $1100^{\circ}C$. The mean size of the powders was increased twice, however, it has very uniform distribution in its size and shape. 분자 단위의 균일한 조성을 가지는 $BaCeO_3$ 나노 분말을 Pechini법에 기초한 citrate 공정을 통하여 합성하였다. 금속 이온의 chelating제로서 citric acid를, 반응 촉매로서는 ethylen glycol을 각각 사용하여 고분자 전구체를 형성시켰고, 이를 기반으로 $900^{\circ}C$의 온도에서 4시간동안 열처리하여 약 100nm의 균일한 크기와 형상을 가진, 사방정 구조의 단일상 $BaCeO_3$ 분말을 합성하는데 성공하였다. 잔존하는 미량의 $CO_3^{2-}$는 $1100^{\circ}C$ 이상의 온도에서 완전히 분해되었고, 이 때 평균 입도 는 약 2배 증가하였으나 매우 균일한 분포를 나타내었다.

자율이동로봇군의 협조행동을 위한 지역적 통신 방식에 있어서 정보전파 해석 및 카오스 현상 분석

이동욱,심귀보,Lee, Dong-Wook,Sim, Kwee-Bo 대한전자공학회 1999 電子工學會論文誌, S Vol.s36 No.6

자율분산로봇시스템에서 협조행동을 위한 로봇의 센싱과 통신 기능은 필수적이다. 일반적으로 대역적 통신시스템에서 로봇의 대수가 증가하면 통신자원의 제한과 정보의 범람이 발생한다. 따라서 이 경우 지역적 통신방법이 유리하다. 본 논문에서는 지역적 통신에 의한 정보의 전파를 해석하고 최적의 통신반경을 찾기 위한 3가지 방법을 제시한다. 또한 로봇이 정보를 획득하고 소실할 경우 발생하는 군의 카오스 행동을 피하기 위한 조건을 찾는다. The sensing and communication abilities of a mobile robot are essential to cooperative behavior in distributed autonomous robotic systems. In general, as the number of robot goes on increasing, the limitation of communication capacity and information overflow occur in global communication capacity and information overflow occur in global communication system. Therefore a local communication is more effective than global one. In this paper, we analyze information propagation mechanism based on local communication. To find an optimal communication radius, we propose three methods with different conditions. Also, to avoid chaotic behavior which occurs when a robot obtains and loses information, we find stable condition of information propagation.

개선된 전처리 과정을 이용한 지문 인식 시스템

이동욱,안도랑,이지원,Lee Dong-Wook,Ahn Do-Rang,Lee Jee-Won 한국융합신호처리학회 2006 융합신호처리학회 논문지 (JISPS) Vol.7 No.2

지문에 기반을 둔 인식시스템은 오래 전부터 사용되었다. 지문은 이미 잘 알려진 바와 마찬가지로 개개인이 서로 다른 특징을 가지고 있기 때문에, 가장 널리 사용되는 생체계측적인 특징의 하나이다. 그러나 지문 인식 시스템은 입력 지문 영상의 상태가 나쁜 경우 인식 성능이 크게 저하되는 치명적인 약점이 있다. 본 논문에서는 이런 문제점을 해결하기 위해 향상된 방향과 향상된 이진화 및 세선화 영상을 이용한 영상 향상 알고리즘을 전처리 과정에서 사용한다. 영상 향상의 목적은 입력 지문 이미지의 품질을 정확히 측정하고, 지문 영상의 융선과 골의 구조를 개선시키는 것이다. 또한 인식 속도를 향상시키기 위하여 색인 테이블을 사용한 융선의 방향 정보 추출 방법을 제안하였다. 제안한 지문 인식 시스템이 특징점 추출과 인식 성능에서 향상되었음을 실험을 통해서 확인할 수 있었다. Fingerprint-based verification system has been used for a very long time. Because of their well-known uniqueness and immutability, fingerprint is one of the most widely used biometric features. However, fingerprint identification system has such a critical weakness that the performance of verification is reduced drastically for a poor input fingerprint. In this paper, an image enhancement algorithm using enhanced direction and enhanced binary and aiming image is used to mitigate the problem in the preprocessing. The goal of image enhancement is to estimate the quality of input fingerprint image and to improve the clarity of ridge and valley structures of input fingerprint image. Also, a ridge orientation extraction method using index table is proposed to improve the speed of verification. It is shown by the experiments that proposed fingerprint verification system improves the minutiae extraction accuracy and performance of verification.

편마비환자의 환측 하지 외회전 정도가 기립균형에 미치는 영향

이동욱,곽길환,배성수,Lee Dong-Wook,Kwak Kil-Hwan,Bae Sung-soo 대한물리치료학회 2003 대한물리치료학회지 Vol.15 No.3

The two groups each consisting of 28 people who had an adult hemiplegia due to a brain injury received two different methods of exercises to reduce the angle to which the affected lower limb rotates externally. The comparisons between the two groups were made for the changes of the angle in external rotations measured between pre and post test. The static balance index values taken during pre and post tests were also compared. In addition, the correlations of the angle to which the affected lower limb rotates externally with static balance index values were analyzed. The result were as follows: 1. A statistical analysis indicated that in group one having taken simple R.O.M exercises, the angle to which the affected lower limb rotates externally and the static balance index values were both significantly different between pre and post test (P<.01). 2. A statistical analysis indicated that in group two having taken a pattern movement, both the angle to which the affected lower limb rotates externally and static balance index values were significantly different between pre and post test (P<.01). 3. A significant difference between simple R.O.M exercises group and pattern movement exercises groupwas shown only for the angle to which affected limb rotates externally not for static balance index values (P<.01), 4. Pearson correlation coefficient for the angle to which the affected limb rotates externally with static balance index values was found to be significant only in pattern movement exercises group (P < .05).

소아에서 유주비장에 대한 비장고정술

이동욱,김상윤,Lee, Dong-Wook,Kim, Sang-Youn 대한소아외과학회 1995 소아외과 Vol.1 No.1

Torsion of the wandering spleen is a rare condition especially in children. Unfortunately, splenectomy was the advocated treatment of choice for wandering spleen in many children up to 1985 in spite of the well-known possibility of overwhelming postsplenectomy sepsis. Because of the conclusive evidence of the vital function of the spleen in infection, indication of splenectomy have been revised and more attention has been paid to preserving the spleen where possible. We are presented a girl with splenic torsion, seen as a migratory abdominal mass and intermittent vague abdominal pain. Splenopexy by fixation of the spleen to the diaphragm and posterolateral peritoneum and the use of Avitene in the splenic bed was successfully performed. Complete fixation of the spleen was confirmed by ultrasound a year after this procedure was carried out. The clinical presentation, etiology, diagnostic procedures and management are discussed also.

Food Restriction as An Effective Modulator of Free Radical Metabolism in Aging Rats

이동욱,유병팔 ( Dong Wook Lee,Byung Pal Yu ) 생화학분자생물학회 1991 BMB Reports Vol.24 No.2

Chronic dietary restiction without malnutrition extends both the mean and maximum life span of all laboratory organisms so far tested. This life-extension is attributed to numerous beneficial effects of well-maintained physiological systems, and the retardation of chronic diseases. Although the biological mechanisms of these anti-aging actions by dietary restriction are not known, recent evidence indicated that modulation of free radical activity might play important roles in such beneficial action. Our present study with SPF male Fischer 344 rats provides further data that the anti-radical action of dietary restriction suppresses the formation of reactive oxygen species, enhances the antioxidant capacity, and increases the membrane resistance against oxidative stress. Based on these results we propose that dietary restriction is an effective modulator of free radical activity.

서울시 아파트단지의 녹지배치 및 식재구조 변화 연구

이동욱,이경재,한봉호,장재훈,김종엽,Lee, Dong-Wook,Lee, Kyong-Jae,Han, Bong-Ho,Jang, Jae-Hoon,Kim, Jong-Yup 한국조경학회 2012 韓國造景學會誌 Vol.40 No.4

본 연구는 서울시 아파트단지의 시기별 녹지배치구조와 식재구조의 변화과정을 분석하여 보다 친환경적인 아파트단지 내 녹지조성 개선방안을 제시하고자 하였다. 연구대상지는 서울시에 조성된 아파트단지 중 조성시기, 용적률, 지하주차장에 의한 지반현황, 녹지율의 차이가 뚜렷한 아파트단지 12개소를 선정하였다. 연구대상지 유형화는 시기별로 녹지율과 지반현황을 기준으로 녹지율이 높은(40% 이상) 자연지반 아파트, 녹지율이 낮은(40% 미만) 자연지반 아파트, 녹지율이 낮은(40% 미만) 인공지반 아파트, 녹지율이 높은(40% 이상) 인공지반 아파트 네 가지로 구분하였다. 아파트단지 녹지배치 구조의 가장 근원적 변화요인은 녹지율과 인공지반 여부로 용적률이 상승하면서 주차장 면적비율도 높아져 상대적으로 녹지율은 낮아졌다. 녹지배치구조가 가장 많이 변한 녹지유형은 전면녹지와 완충녹지로 전면녹지는 녹지율이 높은 자연지반 아파트의 평균 녹지 폭 10.0m에서 3.5m, 2.7m, 4.5m로 시기별로 축소 변화하였다. 완충녹지는 녹지율이 높은 자연지반 아파트에서 평균 녹지 폭 15.0m로 단지외곽 경계부를 연결하였으나, 녹지율이 낮은 인공지반 아파트에서 주차장 확대로 평균 녹지 폭이 7.7m, 2.7m로 점차 축소되고 일부 구간은 단절되었으나, 2001년 이후 녹지에 대한 인식변화로 다시 평균 녹지 폭이 3.8m로 넓어지면서 연결되었다. 녹량 변화를 살펴보면, 녹지율이 높은 자연지반 아파트 녹지용적계수가 $1.27m^3/m^2$이었고, 식재밀도가 높아지면서 녹지율이 낮은 자연지반 아파트의 녹지용적계수가 $3.47m^3/m^2$로 가장 높았다. 반면에 녹지율이 높은 인공지반 아파트의 녹지용적계수는 $0.72m^3/m^2$로 매우 낮은 상태이었다. 식재밀도는 교목 아교목층의 경우 5.0주/$100m^2$에서 14.5주/$100m^2$로 증가하였다. 아파트단지 녹지를 보다 친환경적이고 기능적으로 조성하기 위한 방안으로 녹지율 40% 이상의 아파트단지 내 전면녹지는 녹지 폭 4.5m 이상으로 확대하여 정원개념의 경관 식재지로 조성하고, 후면녹지는 녹지 폭 5.0m이상으로 확대하고 복층구조로 식재하여 녹지량을 증진하는 것을 제시하였다. 측면녹지는 수고가 높은 수종을 식재하여 벽면 차폐와 녹음기능을 증진하고, 완충녹지는 자생수종을 자연림에 가까운 다층구조로 조성하는 생태적 배식기법을 적용하면서 단지내부녹지와 연결해야 할 것으로 판단되었다. This study was carried out to propose the improved method by analyzing the change of green space arrangement and planting structure of apartment complexes in Seoul. 12 survey sites, which have obvious differences, were selected by reflecting the change of floor area ratio, underground parking place, and green space ratio. We divided the survey sites into four types that high green ratio(over 40%) apartment on natural ground, low green ratio(under 40%) apartment on natural ground, low green ratio(under 40%) apartment on artificial ground, and high green ratio(over 40%) apartment on artificial ground each period based on green space ratio and ground structure, plant crown volume, planting density, and planting pattern. The main factors of change of green space arrangement were green space ratio and ground structure. The Green space ratio was changed by the floor area ratio with constructing underground parking place and floor area ratio was adjusted by government policy and economic status. Average width of front green area has been changed from 10.0m in high green ratio apartment on natural ground for 3.5m, 2.7m, and 4.5m each period. The average width of the buffer green area has been changed from 15.0m in high green ratio apartment on natural ground of 7.7m, and 2.7m by extending parking place in the low green ratio apartment of artificial ground, so buffer green areas have been reduced and disconnected. So buffer green area in apartment complexes has been extended that the average width of the buffer green area was 3.8m caused by growing recognition of green since 2001. The ratio of native plant in canopy layer was increased from 45.1 % in the case of the high green ratio apartment of natural ground in 1980~1983 to 55.6%. Average plant crown volume increased from $1.27m^3/m^2$ in high green ratio apartment on natural ground for $3.47m^3/m^2$ in a low green ratio apartment on natural ground. But average plant crown volume is $0.27m^3/m^2$ in the high green ratio apartment of the artificial ground plant density of canopy layer was changed from 5 individuals per $100m^2$ to 14.5 individuals per $100m^2$. We should construct the buffer green area with natural ground and get the function of ecological and beautiful environment regarding to garden concept in case of front green area, width 4.5m. We should get the function of increasing green volume by multi-layer planting with shade woody species and flower woody species in case of back-side green area, width over 5.0m. We should get the function of covering the wall and increasing green landscape by planting with high woody species in case of side green area. We should apply the ecological planting technique to buffer green area and connect buffer green area to inner green area in apartment complexes.

탄성표면파 콘벌버를 이용한 직접 시퀀스 대역 확산 통신에서의 DPSK 복조에 관한 연구

이동욱,조관,황금찬,Lee, Dong-Wook,Cho, Kwan,Whang, Keum-Chan 한국통신학회 1990 韓國通信學會論文誌 Vol.15 No.6

This paper reports on the development of a DPSK demodulator of DS spread spectrum communications that use one SAW convolver. The spreading code chip pattern is changed from bit to bit in data portion of packet. And code chip is PSK modulated. Compared with simulation, experiment shows that the DPSK signal spreaded can be demodulated by using only one SAW convolver. And the theoretical performance of this DPSK demudulator is equal to CSK demodulator wich uses two SAW convolvers. 본 논문에서는 한 개의 탄성표면파 콘벌버를 사용한 직접 시퀀스 대역 확산 통신시스템에서의 DPSK 복조기를 제작, 실험을 하고, 이론적인 고찰을 하였따. 제작한 DPSK 복조 시스템은 SSMA를 위하여 각 데이터 마다 다른 코드로 대역 확산시켰으며, 코드 칩은 PSK로 변조하였다. 본 논문에서 제안한 복조 시스템의 출력은 시뮬레이션 파형과 같음을 확인하였으며, 이론적인 고찰 결과 두개의 콘벌버를 사용한 CSK 복조 시스템과 같은 성능을 보였다.

흰쥐 신장의 NAD 의존성 α - glycerophosphate 탈수소 효소의 정제 및 성상

이동욱,이희성 ( Dong Wook Lee,Hee Sung Lee,Sung Hye Cho ) 생화학분자생물학회 1988 BMB Reports Vol.21 No.3

NAD-linked α-glycerophosphate dehydrogenase(EC 1.1.1.8) in rat kidney existed as four different isozymic forms with an isoelectric point at pH 6.9, 6.6, 6.4 and 6.2, respectively. The major isozymic form(PI 6.6) was purified using several chromatographic procedures involving an ion exchange and two affinity chromatography steps. The 1,078 fold purified enzyme was homogeneous, nucleotide free protein. The molecular weight of the major isozyme was 62,000 daltons, the optimal pH and temperature for its catalytic activity were 10.0 and 55℃, respectively. At the optimal temperature this enzyme was rapidly inactivated(t_(1/2) = 1.5 min). The major isozyme was activated by the addition of cations such as K^+, Na^+, Mg^(++) or Ca^(++), and was strongly inhibited by alkylating agents such as P-hydroxymercurybenzoate or iodoacetamide. Glycerophosphate oxidation reaction obeyed the Michaelis-Menton behavior with Km values of 3.22 and 0.31 mM for glycerophosphate and NAD, respectively. The data suggest that although the isozyme pattern of NAD-linked α-glycerophosphate dehydrogenase is quite different by tissue or species of the animal the physico-chemical properties of the major isozymic form are very similar each other except the affinity for substrate and coenzyme.

Purification and Properties of the Major Isozymic Form of NAD-linked ${\alpha}$-Glycerophosphate Dehydrogenase from Rat Kidney

이동욱,이희성,조성희,Lee, Dong-Wook,Lee, Hee-Sung,Cho, Sung-Hye 생화학분자생물학회 1988 한국생화학회지 Vol.21 No.3

흰쥐 신장의 NAD 의존성 ${\alpha}$-glycerophosphate 탈수소 효소는 4종의 isozyme으로 존재하였고 그들의 등전점은 pH6.9, 6.6, 6.4 및 6.2였다. 이들중 등전점 6.6인 major isozyme을 blue dextran-Sepharose 4B, DEAE-cellulose, Sephadex G-100 chromatography를 통하여 1,078배 정제하였다. Major isozyme의 분자량은 62,000이고, 반응 최적온도와 pH는 각각 55도 및 10.0이었고, 최적온도에서 쉽게 불활성화 되었다. 이 효소는 일가 및 이가 양이온의 첨가에 의해 활성화 되었으며 p-HMB와 iodoacetamide에 의해 활성이 크게 억제되었고, glycerophosphate와 NAD에 대한 Km값은 각각 3.22 및 0.31 mM 이었다. 이들 결과로부터 이 효소의 isozyme pattern은 조직에 따라 다를지라도 major isozyme의 이화학적 성상은 서로 비슷함을 알 수 있었다. NAD-linked ${\alpha}$-glycerophosphate dehydrogenase(EC 1.1.1.8) in rat kidney existed as four different isozymic forms with an isoelectric point at pH 6.9, 6.6, 6.4 and 6.2, respectively. The major isozymic form(PI 6.6) was purified using several chromatographic procedures involving an ion exchange and two affinity chromatography steps. The 1,078 fold purified enzyme was homogeneous, nucleotide free protein. The molecular weight of the major isozyme was 62,000 daltons, the optimal pH and temperature for its catalytic activity were 10.0 and $55^{\circ}C$, respectively. At the optimal temperature this enzyme was rapidly inactivated$(t_{1/2}=1.5min)$. The major isozyme was activated by the addition of cations such as $K^+$, $Na^+$, $Mg^{++}$ or $Ca^{++}$, and was strongly inhibited by alkylating agents such as P-hydroxymercurybenzoate or iodoacetamide. Glycerophosphate oxidation reaction obeyed the Michaelis-Menton behavior with Km values of 3.22 and 0.31 mM for glycerophosphate and NAD, respectively. The data suggest that although the isozyme pattern of NAD-linked ${\alpha}$-glycerophosphate dehydrogenase is quite different by tissue or species of the animal the physico-chemical properties of the major isozymic form are very similar each other except the affinity for substrate and coenzyme.