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PLD를 이용한 강유전체(PZT, PST, PT)/YBCO 박막 구조의 제작과 전기적인 특성에 관한 연구
김정환,이재형,문병무,Kim, Jung-Hwan,Lee, Jae-Hyung,Moon, Byung-Moo 한국전기전자재료학회 1998 전기전자재료학회논문지 Vol.11 No.7
(PZT, PST, PT)/ YBCO structured have been grown on single crystal $LaAlO_3$ using in-situ Nb:YAG pulsed laser deposition technique. The optimum conditions of fabrication for high quality films have been established under various oxygen pressure. TBCO was used as a metallic electrode for polarizing ferroelectric thin fillms. Lattice mismatch of these materials were found to be with in 3%. As a result XRD patterns and rocking curves, (PZT, PST, PT)/ YBCO multiayered thin films on $LaAlO_3$ substrates showed preferred orientation to c-axis. For invastigation on electrical properties of ferroelectric thin films, remanent polaiztion $P_r$ and coercive field $E_c$ were measured for three samples. At each optimum condition, they showed the values of P_r=60 \mu C/cm^2 and E_c=240kV/ cm for PT, 30\mu C/cm^2 and 105kV/cm for PZT, 1.5\mu C/cm^2$ and 15kV/cm for PST. Frequency dependence of dielectric properties of ferroelectric thin fillms was also investigated. As a result, it showed the frequency dependence was relatively small in the range of 10Hz~10kHz.
새로운 Cyanomethyl-1,3,5-triazine 유도체들의 합성
김정환,김은주,Kim, Jung Hwan,Kim, Un Ju 대한화학회 1996 대한화학회지 Vol.40 No.11
6-Cyanomethyl-1, 3, 5-triazine의 2번과 4번 위치에 amino, n-propylamino, isopropylamino, 및 anilino기가 도입된 새로운 유도체 4들의 합성은 6-chloro-1, 3, 5-triazine 유도체 2'들과 3들을 tert-butyl cyanoacetate로 반응시켜 얻었으며, 6-chloro-1, 3, 5-triazine의 2번과 4번 위치에 amino, n-propylamino, isopropylamino, 및 anilino기가 도입된 유도체 2'들과 3들은 2, 4, 6-trichloro-1, 3, 5-triazine 및 4, 6-dichloro-1, 3, 5-triazine 유도체 2들과 amine 유도체들로부터 합성되었다. New 6-cyanomethyl-1,3,5-triazine derivatives 4 containing amino, n-propylamino, isopropylamino and anilino groups at 2-and 4-position on the 6-cyanomethyl-1,3,5-triazine ring were prepared from 6-chloro-l,3,5-triazine derivatives 2' and 3 with tert-butyl cyanoacetate. The derivatives of 6-chloro-l,3,5-triazine 2' and 3 containing amino, n-propylamino, isopropylamino and anilino groups at 2- and 4-position on the 6-chloro-1,3,5-triazine ring were prepared from 2,4,6-trichloro-1,3,5-triazine as well as 4,6-dichloro-1,3,5-triazine derivatives 2 with amine derivatives.
새로운 BF<sub>2</sub>-Chelate 화합물들의 합성
김정환,김영은,Kim, Jung-Hwan,Kim, Yeung-Eun 대한화학회 2004 대한화학회지 Vol.48 No.4
$BF_2$-chelate 형태의 4-pyrimidylideneacetonitrile 유도체들은 4-pyrimidylideneacetonitrile 유도체들의 H-chelate 화합물들과 boron trifluoride diethyl etherate를 반응시켜 얻을 수 있었다. 또 이들 H-chelate 화합물들은 2-cyanomethylpyridine 유도체들에 여러가지 친전자체들 즉 4,6-dichloropyrimidine, 4,6-dichloro-2-methylpyrimidine, 4,6-dichloro-2-heptadecylpyrimidine, 4,6-dichloro-2-phenylpyrimidine, 4,6-dichloro-5-phenylpyrimidine 그리고 4,6-dichloro-2,5-diphenylpyrimidine을 친전자성 치환반응시켜 만들었다. 화합물에 대한 구조는 분광학적인 방법으로 분석하였다. 4-pyrimidylideneacetonitrile derivatives containing $BF_2$-chelate have been synthesized from H-chelates of 4-pyrimidylideneacetonitrile derivatives and boron trifluoride diethyl etherate. These H-chelates were prepared by the electrophilic substitution of 2-cyanomethylpyridine derivatives with electrophiles such as 4,6-dichloropyrimidine, 4,6-dichloro-2-methylpyrimidine, 4,6-dichloro-2-heptadecylpyrimidine, 4,6-dichloro-2-phenylpyrimidine, 4,6-dichloro-5-phenylpyrimidine and 4,6-dichloro-2,5-diphenylpyrimidine. Structures of the target molecules were identified by spectra methods.
김정환,임창형,박응복,Kim Jung-Hwan,Lim Chang-Hyeong,Bak Ung-Bok 한국임상수의학회 1986 한국임상수의학회지 Vol.3 No.1
Pathological study was made of 173 gallbladders among 652 slaughter pigs. The size and the pH of the bile juice were made of 50 among 173 gallbladders with lesions and 50 normal gallbladders as control. The results are summerized as follows : 1. The histological lesions were shown hyperemia and congestion(83.2%), Iymphocytic infiltration(37.5%), Iympoid hyperplasia(27%), epithelial downgrowth(27%), erosion and ulcer(22%), papillary hyperplasia (20.2%), pericholecystic edema(19.5%), hemorrhage(11%), and leukemic cell infiltration(0.6%). 2. In the gallbladders with lesions mean size was 4.26${\times}$7.88cm in diameter and mean pH is 7.2. In the control means size and mean pH were 4.57${\times}$8.13cm in diameter and 7.1. The difference of size between gallbladders with lesions and these as control was not statistically significant. The pH of bile juice between two showed also no statistically significant difference.
폴리프로필렌 글리콜의 표면-보조 레이저 탈착/이온화에서 선형 비행시간 질량분석기의 분해능 개선을 위한 시간 지연 추출법의 응용
김정환,강위경,Kim, Jung Hwan,Kang, Wee Kyung 대한화학회 2000 대한화학회지 Vol.44 No.4
폴리프로필렌 글리콜의 표면-보조 레이저 탈착/이온화를 이용하여 선형 비행시간 질량 분석기에서 시간-지연 추출법이 분해능 개선, 질량-초점 길이 및 기기 퍼짐 효과의 영향을 수치계산과 비교하여 평가해였다. 비행시간 초점영역은 고저압 펄스의 지연 시간에 비례하였고 지연 시간 변화로 질량 초점 영역을 쉽게 조절할 수있었다. 시간 지연 추출법으로 얻어진 질량 스펙트럼의 분해능은 4500으로 연속추출법(20kV)에 비해 7배 정도 개선되었고 △m=2000의 질량-초점길이를 보여주었다. 시간 지연 추출법에서 기기 퍼짐 요인에 의한 분해능 개선의 한계를 계산하였고 5ns의기기 퍼짐 효과에 의해 동위원소 분리 검출은 분자량 2500까지 가능하였다. 시간 지연 추출법을 이용하여 폴리프로필렌 글리콜 분자가 탄고 표면에서 탈착될 때 생성되는 분열체 시리즈를 개선된 고분해능으로 동위원소 분포 수준으로 확인하였으며 분열 경로 규명 및 동위원소 비 질량분석기로의 응용 가능성을 시험하였다. The pulsed-delayed extraction (PDE) in linear time-of-flight mass spectrometer(TOF MS) is characterized on the enhancement of resolution, mass-depth of focus and effect of instrumentahan 2000. The ion signals separate isotopically by up to molecular weight of 2500 in instrumental broadening of 5 ns, which is a good agreement with calculation. The fragmentation paths of PPG can be sug-gested by the isotopica distributions of fragment series produced when PPG desorbed from graphite surface.
노인 복지를 위한 응급 상황 호출 프로그램의 개발 및 구현
김정환,조면균,김식,Kim, Jung-Hwan,Cho, Myeon-Gyun,Kim, Shik 대한임베디드공학회 2013 대한임베디드공학회논문지 Vol.8 No.2
This paper proposes a system that utilizes USN(Ubiquitous Sensor Network), Bluetooth and smart phone to improve the function of senior houses. In typical approach, a system in a senior house either directly accesses the status of elderly people by its sensor or is alerted by elderly people who trigger an emergency bell, derive a decision and take an appropriate action. In addition, it is possible for a designated social worker to check the status of senior patients through monitoring system connected by UTP(Unshielded Uwisted Pair) cables, but the responsible person has to be present to monitor patients' status. However, the new system, suggested in this paper, embed Bluetooth function in a blood pressure gauge, thus the smart phone receives patients' health information such as blood pressure through Bluebooth, if any abnormal event occurs. Consequently, the smart phone sends SMS(Short Message Service) to a responsible social worker or a designated hospital. When this program in the paper becomes a reality, an unmanned system that is able to determine suitable actions for certain events will be established, even if a social worker were absence.
대기 플라즈마 용사공정을 이용한 Cu계 벌크 비정질 금속 코팅의 미세조직 분석과 나노 압입시험을 이용한 상 분석
김정환,강기철,윤상훈,나현택,이창희,Kim, Jung-Hwan,Kang, Ki-Cheol,Yoon, Sang-Hoon,Na, Hyun-Taek,Lee, Chang-Hee 대한용접접합학회 2009 대한용접·접합학회지 Vol.27 No.6
In this study, Cu-based bulk metallic glass (BMG) coatings were deposited by atmospheric plasma spraying (APS) process with different process conditions (with- and without hydrogen gas). As adding the hydrogen gas, thermal energy in the plasma flame increased and induced difference in the melting state of the Cu-based BMG particles. The microstructure and mechanical properties of the coatings were analyzed using a scanning electron microscope (SEM) with an energy dispersive spectroscopy (EDS) and nano-indentation tester in the light of phase analysis. It was elucidated by the nano-indentation tests that un-melted region was a mainly amorphous phase which showed discrete plasticity observed as the flow serrations on the load.displacement (P - h) curves, and the curves of solidified region showed lower flow serrations as amorphous phase mingled with crystalline phase. Oxides produced during the spraying process had the highest hardness value among the phases and were well mixed with other phases resulted from the increase in melting degree.