Sol-Gel 법에 의한 SnO_2의 물성 및 센싱 특성

박보석,홍광준,김호기,박진성 한국센서학회 2002 센서학회지 Vol.11 No.6

초기 물질은 SnCl_2 · 2H_2O와 C_2H_5OH를 사용하여 sol-gel 법으로 제조된 SnO_2 미세 분말의 제반 물성과 전기적 센싱 특성에 대하여 검토하였다. Gel 분말은 sol을 72시간과 168시간 숙성(aging) 시킨 후 120℃에서 건조하여 제조하였다. 600 ℃ 이하에서는 휘발성 물질이 제거되면서 SnO_2 상이 증가하고, 700℃/30min 열처리로 SnO_2 상 생성은 거의 완결된다. 입자 크기는700℃ 이하에서 30nm 이하로 유사하고 입도 분포도 좁았다. 전기적 성질 측정을 위한 시편은 후막법으로 알루미나 기판위에 제조하였다. 공기 중의 전도성은 450℃ 부터 반도성 세라믹스의 진성(intrinsic) 거동을 보이고, 200-450℃ 구간에서는 SnO_2 입자 표면에서의 산소흡착에 기인해서 전도성 변화가 작았다. 환원성 CO 기체에 대한 응답성, 회복성 그리고 감도 특성은 숙성일자 증가로 향상되었다. Fine particles of SnO_2 were fabricated by the sol-gel powder processing using tin(Ⅱ) chloride dihydrate(SnCl_2 · 2H_2O) and ethanol(C_2H_5OH) as raw materials. The powders were investigated about the properties and electrical sensing. Gel powders were fabricated by drying of sol at 120℃ after aging 72hrs and 169hrs. The amount of SnO_2 phase was increased below 600℃ due to the elimination of volatile components, and the SnO_2 phase was almost completed by the heat treatment at 700℃ for 30min. The grain sizes were about 30nm below 700℃, and it showed the narrow distribution of the grain sizes. The specimens to measure electrical properties were fabricated by the thick film screen printing technique on the alumina substrates. The conductance of SnO_2 was showed the intrinsic behavior of semiconducting ceramics above at 450℃. The constant conductance was observed in the temperature range of 200~450℃. The sensing properties of response time, recovery, and sensitivity of CO were improved with aging time.

SnO_2-ZnO 계 후막센서 구조에 따른 CO 감지 특성

박보석,홍광준,김호기,박진성 한국센서학회 2002 센서학회지 Vol.11 No.3

CO 기체 감지 특성을 향상시키기 위해서 3 mol% ZnO를 첨가한 SnO_2와 3mol% SnO_2를 첨가한 ZnO의 적층 형태를 변화시켜 연구하였다. 적층 구조는 단일층, 복층, 그리고 이종층 구조로 후막 인쇄법을 사용하여 제작하였다. SnO_2-ZnO계에서 제 2상은 발견되지 않았다. 전도성은 SnO_2에 ZnO를 첨가하면 감소하고, ZnO에 SnO_2를 첨가하면 증가하였다. 측정 온도증가와 CO 기체 유입으로 전도성은 증가하였다. 단층 및 복층의 후막센서 구조의 감도 향상은 없었으나, SnO_2 -3ZnO-ZnO · 3SnO_2·substrate 구조의 이종층 센서의 감도는 향상되었다. 센서 구조에 관계없이 I-V 변화는 모두 직선성을 나타내서 Ohmic 접합 특성을 이루고 있었다. The sensing properties of carbon monooxide were investigated as a function of mixing ratio and the lamination structure of 3mol% ZnO-doped SnO_2 and 3mol% SnO_2-doped ZnO. The lamination structures were fabricared monolayer, double layer, and hetero layer of SnO_2, ZnO, and theirs mixture composition using thick film process. There was no second phase by the reaction of SnO_2 and ZnO. The conductance was decreased by the addition of ZnO in SnO_2, but it was increased with the addition of SnO_2 in ZnO. The conductance was increased with temperature and the inlet of CO. There was no improvement of sensitivity in the structure of mono- and double-layer. The hetero-layer structure, however, of SnO_2 · 3ZnO-ZnO · 3SnO_2 showed the higher resistivity and the highest sensitivity. Ohmic characteristics was confirmed by the linear properties for I-V measurements.

대안학교 설립·운영 규정(안)에 대한 비판적 논의

최호성,박창언,김회용 경북대학교 사범대학부속 중등교육연구소 2007 중등교육연구 Vol.55 No.1

정상 혈압쥐와 본태성 고혈압쥐 노화 적혈수에서의 Na, K-ATPase에 관한 연구

정성훈,박창길,허강민,석정호,이재흔 충남대학교 의과대학 지역사회의학연구소 1992 충남의대잡지 Vol.19 No.1

To study the change of Na, K-ATPase of aged erythrocytes in the normotensive and hypertensive rats, the young and aged erythrocytes of Sprague-Dawley rats or spontaneously hypertensive rats were fractionized by density gradient, and ouabain sensitive Rb-uptake and [^3H] ouabain binding sites were measured. 1. In the spontaneously hypertensive rats, blood pressure was significantly increased to 151.5/110.0mmHg(systolic/diastolic). Mean corpuscular volume and membrane protein(mg/10^9 RBC) were decreased and hemoglobin content was increased in the aged erythrocytes. 2. In the normotensive rats, ouabain sensitive Rb-uptake of young erythrocyte was increased as increase of Rb concentration from 4 mM to 8 or 16 mM in the reaction medium, but that of aged erythrocyte was lower than that of young erythrocyte. 3. In the spontaneously hypertensive rats, ouabain sensitive Rb-uptake of young erythrocyte was also increased as increase of Rb concentration in the medium, but lower than that of young erythrocyte of normotensive rats, and that of aged erythrocyte was also decreased compared to that of young erythrocyte and that of aged erythrougte of normotensive ratc. 4. [^3H] ouabain binding sites of aged erythrocyte of normotensive rats and young or aged erythrocyte of spontaneously hypertensive rats were lower than that of young erythrocyte of normotensive rats. From the above results, it is suggested that the decreased activity of Na, K-ATPase in the aged erythrocyte of normotensive and spontaneously hypertensive rats may due to the decreased numbers of enzymes, and these enzymes in the erythrocytes of spontaneously hypertensive rats would changed from the younger erythrocytes than those of normotensive rats or one-kidney Goldblatt hypertensive rats.

대학 건축공학과의 실습학기제에 관한 연구

이승준,한인웅,정구용,조방현,한기원,박재호,김진원 三陟大學校 2000 論文集 Vol.33 No.2

In order to solidify the architectural education in university, we should enlarge the opportunity of field training and develop the field training course system as a part of industry-scholastic cooperation. And we should develop new educational process to bring up potent engineers adaptable to the training affairs, faithful to the educational object of the industrial university.

IIIB 병기 비소세포 폐암의 방사선치료 성적

조문준,박승호,김재성,김선영 충남대학교 의과대학 지역사회의학연구소 1994 충남의대잡지 Vol.21 No.2

To evaluate the effect of radiation therapy in nonsmall cell lung cancer stage IIIB, we analyzed the 23 patients diagnosed NSCLC IIIB and treated curatively with radiation therapy between September 1989 and March 1993 at the department of therapeutic radiology, Chungnam National University Hospital, retrospectively. The actuarial 1 year survival rate was 39.2%, 2 year survival rate was 2.3%, and median survival time was 10 months. The difference of survival rates by performance status, response to radiotherapy, T stage, N stage, tumor size, age, pathologic cell type, combination with chemotherapy was not statistically significant. To increase the survival time and rate of the patients with NSCLC IIIB, further study for adequate radiation fractionation and dose, combination with chemoherapy and surgery will be needed.

전이성 뇌종양에 대한 방사선치료시 예후인자에 관한 연구

김재성,박승호,조문준 충남대학교 의과대학 지역사회의학연구소 1993 충남의대잡지 Vol.20 No.1

To evaluate the effect of radiation therapy and prognostic factors in metastatic brain tumor, we analyzed the 29 patients diagnosed as brain metastases and treated with radiation therapy, retrospectively. We evaluated the symptom palliation effect and mean survival time of patients treated with radiation therapy by means of prognostic factors such as initial performance status, primary site, extracranial metastasis, radiation dose etc. Conclusively, we confirmed the good symptomatic response rate but poor survival time of these patients. Also, this study revealed that prognostic factors of metastatic brain tumor treated with radiation therapy were initial preformance status, age and radiation dose but sex, use of steroid, primary site and extracranial metastasis were not. To increase the survival time of the patients with brain metastases, further study for adequate radiation dose/fractionation schedule, combination with chemotherapy and surgical resection, and stereotactic radiotherapy will be needed.

중소도시 하수관거의 침입수량 및 수질오염 원단위 산정

김옥형,박승기,정재훈,임경호 公州大學校 工學硏究院 生産技術硏究所 2004 論文集 Vol.12 No.-

The volume of wastewater in combined sewers in study areas usually exceeds capacities of the sewer system or the treatment plant during storms. For this reason, combined sewer systems are designed to overflow occasionally and discharge excess waste water. The 6 monitoring sites were selected from two small cities near the Hongsung prefecture during over a rainy season. Monitoring was performed by collecting grab samples and by measuring the rainfall and flow rates during dry and wet seasons. Generally the flow rate of wastewater in combined sewers was rapidly decreased after 23:00 PM and gradually increased from 06:30 AM in all sites during the dry season. Due to monitoring and statistical analysis, the groundwater contributes on sewage volume increase (average 3.4-25.4% more) during experimental periods. Therefore, this research is focus on the investigation of the effects of stormwater and groundwater to combined sewer systems.

아스피린 불내성 천식환자에서 포도상구균에 대한 혈청 특이 IgE 항체 측정

오정미,김승현,윤성호,김상하,서창희,남동호,박해심 대한알레르기학회 2004 천식 및 알레르기 Vol.24 No.2

UASB 공정에 의한 고농도 축산폐수 처리시 유기물 제거와 메탄생성에 관한 연구

원철희,김승호,박은영,임재명 江原大學校 産業技術硏究所 2002 産業技術硏究 Vol.22 No.B

This research was performed to investigate the COD removal efficiency and methane production in slurry-typed swine wastes using UASB(upflow anaerobic sludge blanket)reactor. The USAB reactor was operated from 0.8 through 3.3days of HRT in a range of 3 to 15 kg TCOD/m³/day of volumetric organic loading rate. The removal rate of TCOD was increased with the increase of the HRT. The removal rate of TCOD at an HRT over 2days, became greater than 68% with the methane contents being from 70 to 80%. Methane production rates were increased from 0.27 to 0.36 m³CH₄/kg CODrem. as HRTs were increased from 0.8 to 3.3days.