단일전극을 가진 마이크로 가스센서의 제작 및 특성

송갑득,박영일,이상문,이윤수,최낙진,주병수,서무교,허증수,이덕동 한국센서학회 2002 센서학회지 Vol.11 No.6

센서의 안정도와 감도를 개선시킬 수 있는 단일전극을 가진 열선형 마이크로 가스센서를 제작하였다. 일반적으로, 금속산화물 반도체를 이용한 가스센서는 히터전극과 감지전극의 두 개의 전극을 가지고 있다. 제작된 센서는 히터전극위에 감지물질을 형성하여 단일 전극을 가지는 구조를 가지고 있다. 히터와 감지전극으로 사용되는 Pt는 glass 기판위에 스퍼터링법으로 형성하였으며, SnO_2 감지물질은 제작된 Pt 전극위에 열증착시켜 형성하였다. SnO_2막은 lift-off 공정을 이용해서 패턴을 형성하고 1시간 동안 산소분위기에서 열산화하였다. 제작된 소자의 크기는 1.92x.1 mm^2 이다. CO 가스에 대한 감지특성을 조사한 결과 1,000 ppm에 대해 100 mV의 출력변화를 나타내었으며, 넓은 농도범위(0 ~ 10,000 ppm에서 선형적인 전압출력을 나타내었다. 또한 가스 반응 전과 반응 후의 전압출력을 비교해 볼 때, 1 % 이내의 편차를 나타내는 우수한 회복성을 나타내었다. Micro gas sensor with single electrode was proposed for improving stability and sensitivity, Generally, metal oxide gas sensors have two electrodes for heating and sensing. This fabricated new type sensor have only a single electrode by forming a sensing material onto heating electrode. Pt as a heating and sensing electrode was sputtered on glass and a SnO_2 sensing material was thermally evaporated on Pt electrode. SnO_2 was patterned by lift-off process and then thermally oxidized in O_2 condition for 1 hr., 600 ℃. The size fabricated sensor was 1.9 x 2.1 mm^2. As a result of CO gas sensing characteristics, this sensor showed 100 mV change for 1,000 ppm and linearlity for wide range(0 ~ 10,000 ppm) of gas concentrations. And the sensor shows a good recovery characteristics of 1 % deviation compared to initial resistance.

열적 변화를 이용한 실내환경 가스의 분류

최낙진,심창현,송갑득,주병수,이윤수,이상문,이덕동,허증수 한국센서학회 2002 센서학회지 Vol.11 No.5

단일 기판위에 온도측정용 Pt 박막과 Pt 히터 그리고 가스 감지를 위하여 순수한 SnO_2 박막과 Pt가 첨가된 SnO_2박막을 설계하고 제작하였다. 제작된 소자는 실내환경가스인 이산화탄소, 프로판 그리고 부탄의 분류에 응용되었다. 동작 온도를 가변하기 위하여 히터의 입력 전압을 사다리꼴로 인가하면서 SnO_2 감지막의 반응특성과 실내환경가스들에 대한 분류여부를 조사하였다. 감지막 반응특성곡선에서 여러 변수들을 추출한 후 주성분분석(principal component analysis : PCA)을 통하여 가스 분류 특성을 검증하였다. Two SnO_2 based sensing films(pure SnO_2 and SnO_2/Pt) and a Pt thin film for temperature sensor on an alumina substrate were designed and fabricated for classifying the indoor environmental gases. By controlling the heating power in the shape of trapezoid, unique four sensing response curves created from both SnO_2 film and SnO_2/Pt film. Then, various parameters were extracted from sensing response curves and carried out principal component analysis(PCA). The results confirm that a sensor array with the proposed operating mode was extremely effective in classifying indoor environmental gases such as CO_2, C_3H_8, C_4H_10.

단계중합법에 의한 Core-Shell 구조의 Acrylic Composite Particle 제조에 관한 연구

이선룡,윤주섭,강돈오,설수덕 동아대학교 생산기술연구소 2001 生産技術硏究所硏究論文集 Vol.6 No.2

Core-shell composite latex has the both properties of core and shell components. This unique behavior of core-shell composite latex can be used in many industrial fields. However, in preparation of core-shell composite latex, several unexpected are observed, such as, particle coagulation, low degree of polymerization, and formation of new particles during shell polymerization. To solve the disadvantages, we study the effect of initiator concentrations, surfactant concentrations, and reaction temperature on the core-shell structure of Polymethyl methacrylate/polystyrene and polystyren/polymethyl methacrylate. Particle size and particle size distribution were measured by using Particle Size Analyzer, and the morphology of the core-shell composite latex was determined by using Transmission Electron Microscope. Glass temperature was also measured by using Differential Scanning Calorimeter. To identify the core-shell structure, pH of the two composite latex solutions were measured.

국내에서 유행하는 HIV의 전파 경로에 따른 Subtype 분포

이주실,남정구,김성순,강춘,최병선,김옥진,박미선,성봉모,서순덕,전수경,변승옥,신영오,조해월 대한감염학회 2001 감염 Vol.33 No.5

Background : Previous data have been reported that subtype B is prevalent in South Korea, but neither the extent nor the proportion of subtypes could be evaluated. This study was designed to analyze the distribution of HIV-1 subtypes, temporal instructions and transmission dynamics between epidemiological groups. Methods : 1,280 Koreans had been diagnosed as HIV seropositive during the period 1985 to 2000. Among them, 134 individuals were selected for this molecular epidemiological study. 134 DNAs were isolated from uncultured or cultured peripheral blood mononuclear cells. V3-V5 (0.7 kb) fragment of HIV-1 env gene was amplified by nested polymerase chain reaction and was sequenced. Results : HIV-1 isolates from thirty-seven homosexuals were all subtype B (100%). On the other hand, 66 isolates from 94 heterosexuals were subtype B (70%) and 28 were non B subtypes (30% : 13 A, 4 C, 2 D, 8 E , 1 G). Only subtype B strains were isolated from 73 males who were infected with HIV inside Korea while 16 B and 20 non B subtype strains were isolated from 36 males who were HIV infected outside of Korea. However, B and non B strains were isolated half and half from females who were infected inside Korea except one. Conclusion : The HIV-1 subtype B strains are prevalent in Korea from the early HIV infection until present in both homo and heterosexuals. Non B strains have been transmitted from men who were infected outside Korea to their spouses and casual partners. So, we need further study to monitor subtype B and non B HIV transmission in epidemiological groups of Korea, (Korean J Infect Dis 33:311∼318, 2001)

전도성 고분자 센서 어레이를 이용한 휘발성 유기 화합물 가스 인식

이경문,주병수,유준부,황하룡,이병수,이덕동,변형기,허증수 한국센서학회 2002 센서학회지 Vol.11 No.5

휘발성 유기 화합물 가스(Volatile Organic Compounds)를 인식하고 분석하기 위하여 전도성 고분자 센서어레이를 이용한 시스템을 제작하였다. Polypyrrole와 Polyaniline을 화학중합법으로 센서에 전도성고분자막을 형성하였고 이를 통해 VOC 검지용 센서 어레이를 제작하였다. 센서어레이로부터 측정되는 다차원 데이터는 주성분분석법(PCA)과 RBF(Radial Basis Function Network)을 이용하였다. 제안된 시스템으로 VOCs 가스를 인식하는데 있어서 RBF Network이 PCA방식보다 더욱 효율적인 것으로 판단되었다. We fabricated gas recognition system using conducting polymer sensor array for recognizing and analyzing VOCs(Volatile Organic Compounds) gases. The polypyrrole and polyaniline thin film sensors which were made by chemical polymerization were employed to detect VOCs. The multi-dimensional sensor signals obtained from the sensor array were analyzed using PCA(principal component analysis) technique and RBF(radial basis function) Network. Throughout the experimental trails, we confirmed that RBF Network is effective than PCA technique in identifying VOCs.

젊은 성인에서 흡연에 의한 상완동맥 내피기능의 부전에 관한 연구

이상철,권영주,방덕원,이선해,이보영,김지욱,김영훈,온영근,현민수,김성구 순천향의학연구소 2002 Journal of Soonchunhyang Medical Science Vol.8 No.1

Background and Objectives : Cigarette smoking is a major factor and the most modifiable risk factor for atherosclerosis. Endothelial dysfunction is an early event in atherosclerosis, before the structural change of the systemic arteries. We hypothesized that endothelial dysfunction might be present in the systemic arteries of young adult smokers and that this might be dose-dependent phenomenon. Therefore, we try to certify that smoking is associated with endothelial dysfunction in healthy young adults without other risk factor of atherosclerosis. Subjects and Methods : we studied noninvasively 29 subjects aged 3 to 4 decades without other risk factor of atherosclerosis, they were composed of the two groups, current smokers(n=15) and nonsmokers(n=14). Smoking history varied from 3 to 20 pack years. Using high-resolution ultrasound, vessel diameter and mean flow rate were measured at rest, during reactive hyperemia(with flow-mediated endothelium-dependent dilation), and after sublingual nitroglycerin(NG-induced endothelium-independent vasodilation). Result : Flow mediated endothelium dependent dilation was observed in the control subjects (9.4±3.44%) but was impaired in the smokers(5.8±2.51%)(p=0.004). NG-induced endothelium independent dilation is no difference in all subjects. Conclusion : Cigarette smoking is associated with endothelial dysfunction in healthy young adults.

자동차 실내 환경 감성측정기 개발 및 공조제어 모델링

류정호,주병수,김봉균,임준우,이덕동 경북대학교 센서기술연구소 1998 센서技術學術大會論文集 Vol.9 No.1

A sensibility measurement system that can measure human sensibility at the automobile cabin environment is developed in this paper. Five kinds of sensors that can measure temperature, humidity, oxygen, CO_(2), and HC gas concentrations are used in this system. Sensibility indexes are defined for each sensor datum, and then those are linearly combined to make a total human sensibility index. A stand-alone system is manufactured using a one-chip microprocessor, and simple controls are showed with LEDs. This system was tested for performance in automobile cabin environment and showed good reliability.

양극성 장애 환자의 첫 삽화에 따른 임상적 특징

김윤기,이은,전덕인,유빈,석정호,조현상,김세주 大韓神經精神醫學會 2007 신경정신의학 Vol.46 No.4

Objectives : It has been reported that first episode polarity affected the course and the prognosis ofbipolar disorder. However, there is remarkable paucity of infbrmation regarding first episode polarity in bipolar disorder. We investigated the clinical characteristics related to the first episode polarity of bipolar patients who had been hospitalized. Methods : Analyses were based on the medical documents of 520 bipolar patients who had been hospitalized in 4 hospitals. We examined clinical features of the current episode, demographics, Past treatment history, suicidal attempt history, family history and comorbidhy. Clinical characteristics were compared between manic onset and depressive onset patients. Results : The mean age of the patients was 36.7 years old : they had 2.1 number of admission history and 6.6 years of illness duration. The patients beginning with depressive onset was 39.4%, and they had more diagnosis of bipolar II disorder, more number of suicidal attempts and reported more depressive mood during index admission than manic onset patients. Conclusion : Depressive onset is a common presentation in bipolar disorder. It is necessary to give more attention to depre-ssive episode in bipolar disorder. Prospective study needs to explore the correlation of first-episode of polarity and course of the illness in the future.

뇨(尿)중 3-Methylhistidine 함량의 측정과 이용

정수현,서형주,김윤숙,이효구,강덕호 한국식품영양학회 1996 韓國食品營養學會誌 Vol.9 No.2

기존의 방법을 일부 수정하여 뇨중 3-methylhistidine을 분석하였다. 뇨중 3-methylhistidine을 fluorescamine 유도체화하여 HPLC에 주입하고 C_18 column과 10 mM acetonitrile/sodium phosphate buffer(pH 7.5)로 분리·용출시켜 형광검출기로 측정하였다. 3-methylhistidine의 체류시간은 7분 이내이었으며, histidine과의 분리상태도 서로 간섭함이 없이 양호하였다. 뇨에 3-methylhistidine을 첨가하고 이를 분석하였을 때의 회수율은 93∼106%로 높은 수준이었다. 체육학과 남학생중 웨이트 트레이닝 단련자와 비단련자를 대상으로 조사한 단기간의 웨이트 트레이닝에 따른 뇨중 3-methylhistidine 함량의 변화는 두 집단 모두 웨이트 트레이닝후의 3-methylhistidine 분비량이 유의하게 증가하였다. A modified method is given for the precolumn derivatization and subsequent high-pressure liquid chromatographic seperation of 3-methylhistidine from urine. The elution contained isocratic solution with acetonirile and 10 mM sodium phosphate(pH 7.5) requires less than 7 min. The recoveries of 3-methylhistidine from urine control were 93% to 106%. 3-Methylhistidine determinations were performed on urine samples from volunteers who were both male trained and non-trained physical undergraduates. As the result, urinary 3-methylhistidine content of volunteers increased significantly after weight training.

뇌 아밀로이드 혈관병과 고혈압성 뇌출혈의 감별에 있어서 Apolipoprotein Eε4와 점상 출혈 분포의 유용성

김용범,이광호,이수주,나덕렬,조수진,정진상,이원용 대한신경과학회 1999 대한신경과학회지 Vol.17 No.1