• 제목/요약/키워드: LeeWhang

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Kinetics and Mechanism of the Pyridinolysis of Aryl Cyclopropanecarboxylates in Acetonitrile

  • Koh, Han-Joong;Kang, Suk-Jin;Kim, Cheol-Ju;Lee, Hai-Whang;Lee, Ik-Choon
    • Bulletin of the Korean Chemical Society
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    • 제24권7호
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    • pp.925-930
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    • 2003
  • Kinetic studies of the reaction of Z-aryl cyclopropanecarboxylates with X-pyridines in acetonitrile at 55.0 ℃ have been carried out. The reaction proceeds by a stepwise mechanism in which the rate-determining step is the breakdown of the zwitterionic tetrahedral intermediate, $T^{\pm}$. These mechanistic conclusions are drawn base on (i) the large magnitude of ρx and ρz, (ii) the positive sign of ρxz and the larger magnitude of ρxz than normal $S_N2$ processes, (iii) a small positive enthalpy of activation, Δ$H^≠$, and a large negative, Δ$S^≠$, and lastly (iv) adherence to the reactivity-selectivity principle (RSP) in all cases.

Pyridinolysis of O-Aryl Phenylphosphonochloridothioates in Acetonitrile

  • Lumbiny, Bilkis Jahan;Adhikary, Keshab Kumar;Lee, Bon-Su;Lee, Hai-Whang
    • Bulletin of the Korean Chemical Society
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    • 제29권9호
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    • pp.1769-1773
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    • 2008
  • fThe kinetics and mechanism of the reactions of Y-O-aryl phenylphosphonochloridothioates with X-pyridines are investigated in acetonitrile at 35.0 ${^{\circ}C}$. The negative value of the cross-interaction constant, $\rho$XY = −0.46, indicates that the reaction proceeds by concerted $S_N2$ mechanism. The observed $k_H/k_D$ values involving d-5 pyridine ($C_5D_5N$) nucleophiles are greater than unity (1.05-1.11). The net primary deuterium kinetic isotope effects, $(k_H/k_D)_{net}$ = 1.28-1.35, excluding the increased $pK_a$ effect of d-5 pyridine are obtained. The transition state with a hydrogen bond between the leaving group Cl and the hydrogen (deuterium) atom in the C-H(D) is suggested for the studied reaction system.

리니어 컴프레샤용 LOA의 스트로크 센서 없는 제어 방법 (The control method of LOA for a linear compressor without a stroke sensor)

  • 유재유;이철웅;이재춘;황민규;김정철
    • 전력전자학회:학술대회논문집
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    • 전력전자학회 2001년도 전력전자학술대회 논문집
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    • pp.650-653
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    • 2001
  • In recent the energy efficiency of a refrigerator has been restricted extremely. A compressor consumes a great portion of input power in a refrigerator. So it is necessary to develop a more efficient compressor in these days. The existing reciprocating compressor need to a crank shaft to convert the rotating motion to the straight motion and is not efficient. But the linear compressor using mechanic resonance is efficient but need a drive instead of a crank shaft to control a position accurately. However it is impossible to apply a stroke sensor practically because of the internal circumstance of compressor. In this paper, A new sensorless stroke control method using the current and voltage of linear compressor is proposed.

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2차원 중간값 필터 디지털 영상 처리 기법을 적용한 화면 정보 보안 (Security in Display Information with Digital Image Processing using 2-Dimensional Median Filter)

  • 황호영;이승주;이석찬
    • 한국정보처리학회:학술대회논문집
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    • 한국정보처리학회 2015년도 추계학술발표대회
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    • pp.878-879
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    • 2015
  • 어플리케이션 구동 시에 화면에 표시되는 데이터는 보안 알고리즘이 적용되지 않은 채로 사용자 및 악의적인 해커들에게 노출된다. 본 논문에서는 악의적인 사용자가 화면을 캡쳐하여 이미지 파일로 저장하거나 디지털카메라로 화면에 노출된 정보의 사진을 찍었을 때 중요 데이터가 유출되지 않도록 화면 출력 이미지를 디지털 영상 처리 기법을 이용하여 변조한다. 사용자가 육안으로 볼 때에는 데이터를 식별할 수 있도록 화면 주사율에 맞추어 변조된 영상에 대한 보완 영상을 번걸아 출력한다.

Cross Interaction Constants As a Measure of the Transition State Structure (Part VI). Nucleophilic Substitution Reactions of Benzyl Chlorides with Anilines and Benzylamines

  • Lee, Ik-Choon;Huh, Chul;Koh, Han-Joong;Lee, Hai-Whang
    • Bulletin of the Korean Chemical Society
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    • 제9권6호
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    • pp.376-378
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    • 1988
  • Results of kinetic studies on the reactions of benzyl chlorides with anilines and benzylamines are reported. Analyses of the cross interaction constants relevant to the degree of bond formation, ${\rho}_{XY}$ and ${\lambda}_{XY}$, are carried out. The magnitudes of the two parameters indicated that the degree of bond formation in the transition state is the typical of that expected for an $S_N2$ reaction, but the reactions with benzylamines appear to have a slightly less degree of bond formation compared with the reactions with anilines.

Nucleophilic Substitution Reactions of Benzyl Benzenesulfonates with Benzylamine in Acetonitrile and Methanol

  • Ikchoon Lee;Chul Hyun Kang;Pyoung Sam Park;Hai Whang Lee
    • Bulletin of the Korean Chemical Society
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    • 제12권3호
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    • pp.282-286
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    • 1991
  • Kinetic studies of the reactions of benzyl benzenesulfonates with benzylamines in methanol and acetonitrile have been carried out. The reaction was found to proceed by a dissociative $S_N2$ in MeCN but by an associative $S_N2$ mechanism in MeOH. The transition state was rather loose in MeCN whereas it was tight in MeOH, in contrast to a tighter TS in MeCN for the corresponding reactions with aniline. The reaction of benzylamine in MeOH was characteristic of the highly solvated nucleophile, benzylamine, compared to the normal reaction in MeCN.

딥러닝 방식을 이용한 환유 해소 (Metonymy Resolution based on Neural Approach)

  • 황태선;이찬희;양기수;이동엽;구영은;전태희;임희석
    • 한국정보과학회 언어공학연구회:학술대회논문집(한글 및 한국어 정보처리)
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    • 한국정보과학회언어공학연구회 2019년도 제31회 한글 및 한국어 정보처리 학술대회
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    • pp.375-379
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    • 2019
  • 언어학에서의 환유법은 표현을 위해 빌려온 대상이 다양한 의미로 해석 가능하기에 매우 어렵고 난해한 분야이다. 환유의 특성 상 주어진 엔티티의 환유 여부를 구분하기 위해서는 앞뒤 단어와의 연관성 뿐만 아니라 문장 전체의 문맥 정보에 대한 고려가 필수적이다. 최근 이러한 문맥 정보를 고려하여 학습된 다양한 모델들이 등장하면서 환유법에 대한 연구를 하기에 좋은 환경이 구축되고 있다. 본 논문에서는 언어학적 자질 정보를 최소화한 딥러닝을 이용한 환유 해소 모델을 제안한다. LSTM 기반의 feature-based 모델과 및 BERT, XLNet, RoBERTa와 같은 fine-tuning 모델들에 대한 실험을 진행하였다. 실험 결과, fine-tuning 모델들이 baseline과 비교하여 뛰어난 성능 향상을 가져왔으며, 특히 XLNet 모델은 두 개의 환유 해소 데이터 SemEval 2007와 ReLocaR에 대해 각각 90.1%과 95.8%의 정확도를 보여주었다.

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CONTINUOUSLY TUNABLE VISIBLE LIGHT EMISSION FROM QUANTUM-CONFINED EXCITONS IN ION BEAM SYNTHESIZED SI NANOCRYSTALS IN $SiO_2$

  • Kwon, Young-Soo;Rho, T.H.;Lee, Chaee-Kang;Cha, G.B.;Hong, Soon-C.;Nam, J.;Kim, J.H.;Kang, H.J.;Moon, D.W.;Ha, Y.H.;Paik, Sun-M.;Song, H.;Lee, Eung-S.;Yoo, Sung-M.;Choi, Jin-M.;Whang, Chung-N.;Kim, J.S.;Ihm, K.W.;Hwang, C.C.;Kim, H.S.;Kim, Y.K.;Park, C.Y.
    • 한국재료학회:학술대회논문집
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    • 한국재료학회 1998년도 IUMRS-ICEM ABSTRACT BOOK
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    • pp.85.4-85
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    • 1998
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Kinect Sensor 기반의 BMI 측정 애플리케이션 설계 및 구현 (A Design and Implementation of BMI Measurement Application Based on Kinect Sensor)

  • 이원주;최민수;이준혁;김혜왕
    • 한국컴퓨터정보학회:학술대회논문집
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    • 한국컴퓨터정보학회 2022년도 제65차 동계학술대회논문집 30권1호
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    • pp.121-122
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    • 2022
  • 본 논문에서는 키넥트 센서 기반의 체질량지수(BMI, Body Mass Index) 애플리케이션을 설계하고 구현한다. 이 애플리케이션은 키넥트 센서에서 측정하는 사용자의 신체 픽셀 정보와 거리정보를 활용하여 체질량 지수를 측정한다. 또한, 키넥트 센서에서 인식한 사용자의 스켈레톤 정보와 20개 조인트 정보를 활용하여 사용자의 신장을 측정한다. 사용자와 관리자의 화면을 별도로 구성해 관리자 화면상의 버튼으로 Database에 저장하는 기능을 제공한다.

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조선시대 문헌에 나타난 가족경제생활관 (Home Economic View in Literatures and Documents of Cho-sun Dynasty)

  • 이길표
    • 가정과삶의질연구
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    • 제13권4호
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    • pp.115-124
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    • 1995
  • The purpose of this study was to accept its contents as lessons for today and to search for the correct way to lead home economy of the future by way of retranslating home economic view in literatures and documents of Cho-sun Dynasty(1392-1910) Through studying Cho-sun's literatures and documents: 「Ne-hun」 by the queen So He 「Kyou-dyoung-yo-ram」by Lee Whang 「Kyung-mong-yo-kul」by Lee Yul 「Song-ho-sa-sul」by Lee IK 「Sa-so-jol」by Lee Duk Moo「Buk-hak-ee」 by Park Je Ka 「Mok-min-sim-su」 by Jung Yak Yong. The results of this study can be summarized as follows : 1. The view of income: 1) Cut down on the too much greed of property (property income) 2) Work hard with diligence(earned income). 2. The view of expense : 1) Get food clothing and housing with frugality 2) Spend money for home rites and reception of guests with manner and truth without extravagnace. 3. The view of buying and selling: Buy and sell with credit. 4. The view of borrowing and lending: Borrow and lend money honestly,. 5. The view of home book-keeping : Keep home book-keeping every day. 6. The view of economic preparation : Save for a rainy day wisely.

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