Impedance를 이용한 전도성고분자 센서의 가스감응특성

이경문,유준부,이병수,전희권,이상태,이덕동,허증수 경북대학교 센서기술연구소 2002 센서技術學術大會論文集 Vol.13 No.1

SnO₂/TiO₂후막형 습도센서의 제조 및 특성

이건동,이재현,박효덕,이덕동,최흥문 경북대학교 센서기술연구소 1991 센서技術學術大會論文集 Vol.2 No.1

SnO_(2) doped with TiO_(2) and other activating agents, is used as a raw material to prepare humidity sensors. SnO_(2) is an n-type semiconductor whose resistance is described as a function of relative humidity. SnO_(2)/TiO_(2) thick film humidity sensors have been fabricated by using typical silk screen printing techniques. The humidity sensitivity of SnO_(2)/TiO_(2) thick film has been investigated. And the sensing characteristics of the fabricated SnO_(2)/TiO_(2) sensors such as resistance change and response time, has been investigated from R.H.20 % to 90 %. Experimental results show that the impedance-humidity characteristics of the humidity sensors depend on the microstructure of surface roughness and pore size distribution.

한약에 의해 유발된 급성 간질성 신염 2례

김덕윤,박동건,김응석,강영모,양창헌,이정호,이동철,이영현,김정란 동국대학교 경주대학 1996 東國論集 Vol.15 No.-

간질성 신염은 신장의 간질을 선택적으로 침범하는 염증성 질환으로 여러가지 원인에 의해 유발되며, 이 중 약물에 의한 경우는 각종 항생제, 비스테로이드성 진통제, 항경련제, 이뇨제, 면역억제제등에 의한 증례들이 보고되고 있다. 현재 각종 질환-특히 만성질환-의 치료에서 한약이 차지하는 비중이 적지 않으나, 그 각각의 성분들이 유발할 수 있는 부작용들에 대한 연구는 거의 없는 실정이다. 저자들은 관절염 치료를 위해 중국산 한약을 복용한 후 복통, 피로감 및 육안적 혈뇨를 주소로 내원한 두 환자에서, 단백뇨와 신기능 장애를 보여 시행한 신조직 생검상 급성 간질성 신염에 합당한 병리학적 소견을 보이고, 한약 복용 중지 후 급속한 회복을 보여, 한약에 의해 유발된 것으로 사료되는 급성 간질성 신염 2예를 경험하였기에 문헌고찰과 함께 보고하는 바이다. Acute interstitial nephritis is a disease characterized by renal interstitial inflammatory cell infiltration and acute renal functional deterioration. This is caused mainly by antibiotics, NSAID and diuretics such as thiazide, but cases induced by herb medication are rare. We experienced two cases of acute interstitial nephritis after treatment with herb medication. One 71-year-old female patient and the other 60-year-old female were admitted to the hospital because of general weakness and gross hematuria. Microscopic hematuria, pyuria, and proteinuria were presented. After definitive diagnosis with a renal biopsy, we noted rapid recovery of renal function by drug withdrawal and steroid therapy. We report these cases with a review of the referenced literatures. Key Words : Herb medication, Acute Interstitial nephritis.

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.

열공형과 비열공형 피질하 혈관성 치매에서 위험인자의 차이에 관한 비교 연구

배희준,정지향,유경호,나덕렬,김상윤,최경규,양동원,손의주,이상도,김재우,박경원,김응규,이재홍,박미영,한일우,함동석,최문성,하충건,최성혜,이애영,이병철,한설희 대한치매학회 2003 Dementia and Neurocognitive Disorders Vol.2 No.2

Backgrounds and Objectives: Vascular dementia is a group of dementing disoders arising from various stroke syndrome. Among these. subcortical ischemic vascular dementia (SIVD) is regarded as a relatively distinct clinical entity. However, MRI patterns of SIVD are not homogenous. In some patients, lacunes are dominant, and in others, subcortical white matter changes are. This study was designed to compare risk factor profiles between SIVD with and without multiple lacunes. Methods: We divided 47 subjects (22 males, mean age. 68 years) recruited from VADAPET (Multicenter Trial For Evaluation Of The Changes In the PET Images Of Subcortical Vascular Dementia Patient) study into two groups one with more than 5 lacunes in deep gray matter (lacune group) and the other with 5 or less(non-lacune group) Clinical characteristics and laboratory findings of two groups were compared. Results: Nineteen of 47 patients (40%) belonged to the lacune group. The lacune and non-lacune groups d d not differ in the following variables: age, hypertension, diabetes mellitus, hyperlipidemia heart disease, history of stroke or TIA, history of trauma or major surgery, family history of hypertension stroke, or dementia, age at diagnosis of dementia, body mass index, white blood cell count, ESR, CRP, fibrinogen, hemoglobin A1C, total cholesterol. LDL cholesterol creatinine, proteinuria, glucosuria, and microhematuria. However, male sex, smoking alcohol. hemoglobin, and HDL cholesterol were possibly associated more with lacune group SIVD than with non-lacune group (p<0 1) Multivariate analyses revealed that smoking, hemoglobin, and HDL cholesterol were independent predictors of SIVD with multiple lacunes Conclusion: Our study suggests that SIVD with multiple lacunes may be significantly different in smoking habits hemoglobin, and HDL cholesterol from SIVD without multiple lacunes.

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.

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.

산화코발트계 산소센서의 제작 및 그 특성

이재현,전춘배,이덕동 경북대학교 센서기술연구소 1990 센서技術學術大會論文集 Vol.1 No.1

Co_(1-x)Mg_(x)O ceramic oxygen sensors were prepared by pressing at 0.3 ~ 1.5 ton/cm^(2) with or without binder, intending to change porosity and average grain size on the surface purposely. Microstructures of prepared Co_(1-x)Mg_(x)O ceramics were observed, the electrical properties and the sensitivity characteristics for oxygen gas were investigated in the specimen temperature range of 700~1000 °C and for oxygen partial pressure range of 1~10^(-4) atm. Temperature dependence of the resistivity of the specimen showed NTC behavior, average grain size increased and porosity decreased with increasing compaction pressure. The slopes of the resistivity of the specimens on the oxygen partial pressure decreased with increasing average grain size and with decresing porosity. Particularly, specimen pressed by 0.3 and 0.5 ton/cm^(2) showed the highest sensistivity to oxygen gas. In general optimum operating temperature was 800 °C.

실관막을 이용한 중금속 추출에서 물질전달에 미치는 분배비의 영향

李龍珍,金英一,陳道源,黃德基,朴東源 동아대학교 공과대학부설 생산기술연구소 1997 生産技術硏究所硏究論文集 Vol.2 No.1

The liquid-liquid extractions by use of microporous hollow fiber membrane modules are fast compared with conventional extraction equipment. Because they have a large surface area per volume. Solute diffuses out of the feed solution, through the fibers' porous wall, and into the extractant. The extractant and feed can be contacted at high speed, there are no problems with flooding, loading and channeling. Moreover, these modules should be characterized by low investment and operating costs because of the reduced hardware and the favorable hydrodynamics which minimizes concentration polarization and membrane fouling. In this paper, it was investigated the extraction selectivities for liquid-liquid extraction of heavy metal(Cd(Ⅱ)Co(II)) from dilute aqueous solution into the eatractants(EHPNA and TBP) by using the hydrophobic hollow fiber module. We also examined the effect of distribution ratio on the overall mass transfer coefficients.

배출가스 측정용 가스센서의 개발(Ⅱ)

이덕동,최순돈 경북대학교 센서기술연구소 1994 연차보고서 Vol.1994 No.-

대기 및 배출가스 중 CO_2, HC 및 SO_x를 검지정량할 수 있는 고체전해질 소자의 제조공정을 개발하고 그 특성을 조사하였다. CO_2 가스감지소자의 모제로서는 1차년도에 사용한 Na_3PO_4와 ZrSiO_4의 혼합물로 형성되는 NASICON 대신에 건식 또는 습식혼합법으로 얻어진 LISICON을 사용함으로써 CO_2 농도에 따른 소자출력전압의 직선성을 향상시켰다. 졸겔법으로 제작된 LISICON CO_2 센서는 0∼5000 ppm의 CO_2 가스농도영역에서 우수한 감도 및 양호한 직선성을 나타내었다. 탄화수소계가스센서는 미세분말의 SnO_2를 모제로 사용하여 후막형으로 제조되었으며 부탄, 프로판 및 메탄에 대해 높은 감도와 안정성을 갖는 소자의 제조공정을 확립하였다. 제조한 소자는 1,000 ppm의 부탄가스 및 메탄가스에 대해 각각 95% 및 80% 정도의 감도를 나타내었으며 장기안정성이 우수하였다. 배출원의 SO_2 가스 농도를 측정할 수 있는 NASICON 고체전해질 센서의 제조공정을 학립하고 습도의존성을 낮출 수 있는 측정전극물질을 개발하였다. 제조한 소자는 SO_2의 농도가 5 ppm에서 90 ppm으로 변화할 때 기전력의 변화는 약 90㎹ 정도였으며 300∼500의 동작온도에서 이론치와 잘 일치하는 출력특성을 얻었다. The air pollution problem is known to be very serious, for the extent of the damage caused by the harmful gas components in air. There are many noxious air components, i.e. SO_x, CO, NOx. CO_2 is not seriously harmful to us but it is the main cause of the warm earth. The level of CO_2 in the atmosphere has been appreciably increased since the Industrial Evolution. Now the level comes to be about 350 ppm. So there needs a consideration of the counterplan to control the CO_2 level in the atmosphere. And SO_x is very toxic gas component to human beings, animals and plants. Only in the low level of SO_x(∼ppm), it gives us fatal damage. And also hydrocarbon gases are known to be a cause of the warm earth. So we need the sensor which enable us to defeat low level HC gases. The purpose of this study is to develop the sensors to detect CO_2, HC and SO_x as the principal air pollutants. To fabricate CO_2, we synthesized LISICON powder (Li ion super conductor) by two different methods, dry and wet chemical methods. The LISICON powder by dry method was prepared by using the mixture of Li_3PO_4 and ZrSiO_4. And it was calcined at 900℃ for 10 hours and sintered at 1000℃ for 24 hours to make the LISICON cell. LISICON by wet chemical method was obtained by mixing the solution of several alkoxides(tetraethoxysilane, lithium methoxide, zirconium n-propoxide and tributyl phosphate). And cell was prepared by calcining the green powder at 900℃ for 10 hours and sintering it at 900℃∼1100℃ for 30∼50 hours. The LISICON cells prepared showed very good sensitivity to CO_2 gas. The correlation between emf and CO_2 concentration at various temperatures between 300℃ and 500℃ were obtained. The linearity observed at each temperature showed that the correlation follows a Nernst equation in the test range of 300∼5000 ppm CO_2 quite well. The observed Nernst slope of 80 ㎷/decade at the cell temperature of 450℃ coincided with pretty well with the theoretical value. From the correlations between emf and SO_2 concentration at various temperatures between 300 and 500℃, the observed linearity at each temperature also showed good agreement with Nernst equation in the test range of 5∼90 ppm SO_2. The change in emf value for the change in SO_2 concentration from 5 to 90 ppm was about 90 ㎷. Hydrocarbon gas sensors were fabricated using SnO_2 fine powder, and the characteristics examined. The sensors exhibited high sensitivity and stability to butane, propane and methane. The sensors fabricated can be used to detect the butane and propane gases of 100 ppm level.