大德 및 隣近地域 우물물의 tritium 濃度

李德憲,吳熙弼,田載植 충남대학교 자연과학연구소 1981 忠南科學硏究誌 Vol.8 No.2

Tritium concentrations in well water of Daedong area and its vicinity were measured by means of electrolytic enrichment technique and liquid scintillation counting method. Samples were taken from six different wells spread around Dae-deog Science Town at least ten kilometers and/or from each other, so as not to have any possible influence from other water sources and/or streams. The tritium enrichment factor in the electrolytic process was determined using standardized tritiated water of known activity. Results show that the mean value of tritium concentration in well water of this area is 41.60±2.52 TU with maximum and minimum of 44.33±2.64 TU and 39.20±2.65 TU, respectively, as of September 1981, which are quite reasonably comparable with 40 TU measured by Fireman and Schwarzer for well water.

실리콘 마이크로머시닝을 위한 자기 정렬 특성을 갖는 새로운 실리콘 식각방법과 식각특성분석

李熙德(Hi-Deok Lee),金載官(Jae-Kwan Kim),鄭訓周(Hoon-Ju Chung),韓喆熙(Chul-Hi Han) 대한전기학회 1996 전기학회논문지 Vol.45 No.10

Characterization of Reverse Leakage Current of Shallow Silicide Junction

Lee,Hi Deok,Lee,Sang Gi,Kim,Ha Joong,Lee,Young Jong,Hwang,Jeong Mo 대한전자공학회 1997 ICVC : International Conference on VLSI and CAD Vol.5 No.1

The properties of PECVD-WN_x films produced in a WF_6-N₂-H₂ gas system and their application as a glue layer for a W metallization were investigated. As the N₂/H₂ ratio in reactant gas increased from 0 to 1.5, the nitrogen concentration and the electrical resistivity in WNX film increased from 0 to 25 at % and 25.5 to 1009 Ω-cm, respectively. In the N₂/H₂ ranges, the microstructure of the film was also shown to be changed as bcc-W, mixture of W+WN+W₂N, amorphous or nanocrystal, and W₂N, in turn. The film of the best qualities was obtained at the N₂/H₂ ratio of 0.25, where it represented the most smooth surface, 230μΩ-cm of resistivity, 13 at.% of nitrogen concentration, nanocrystalline structure close to amorphous at as-deposited state, and 90% of bottom step coverage. In order to proceed further CVD-W metallization, a PECVD-W layer was employed as a seed layer for the stable deposition of the thermal CVD-W onto the WNX layer. A tri-layer structure of (thermal)CVD-W/PECVDW/PECVD-WN_x with a good thermal stability was successfully achieved in an in-situ process, and hence its application to CVD-W metallizations seemed to be promising.

BICMOS를 이용한 전류형 고속 8비트 A/D변환기

한태희(Tae-Hi Han),조상우(Sang-Woo Cho),이희덕(Heui-Deok Lee),한철희(Chul-Hi Han) 대한전기학회 1991 대한전기학회 학술대회 논문집 Vol.1991 No.7

Chemiresistive Sensor Array Based on Semiconducting Metal Oxides for Environmental Monitoring

( Hi Gyu Moon ),( Soo Deok Han ),( Min Gyu Kang ),( Woo Suk Jung ),( Ho Won Jang ),( Kwang Soo Yoo ),( Hyung Ho Park ),( Chong Yun Kang ) 한국센서학회 2014 센서학회지 Vol.23 No.1

We present gas sensing performance based on 2Χ2 sensor array with four different elements (TiO2, SnO2, WO3 and In2O3 thin films) fabricated by rf sputter. Each thin film was deposited onto the selected SiO2/Si substrate with Pt interdigitated electrodes (IDEs) of 5m spacing which were fabricated on a SiO2/Si substrate using photolithography and dry etching. For 5 ppm NO2 and 50 ppm CO, each thin film sensor has a different response to offers the distinguishable response pattern for different gas molecules. Compared with the conventional micro-fabrication technology, 2Χ2 sensor array with such remarkable response pattern will be open a new foundation for monolithic integration of high-performance chemoresistive sensors with simplicity in fabrication, low cost, high reliablity, and multifunctional smart sensors for environmental monitoring.

Chemiresistive Sensor Based on One-Dimensional WO3 Nanostructures as Non-Invasive Disease Monitors

( Hi Gyu Moon ),( Soo Deok Han ),( Chul Ki Kim ),( Hyung Ho Park ),( Seok Jin Yoon ) 한국센서학회 2014 센서학회지 Vol.23 No.5

In this study, a chemiresistive sensor based on one-dimensional WO3 nanostructures is presented for application in non invasive medical diagnostics. WO3 nanostructures were used as an active gas sensing layer and were deposited onto a SiO2/Si substrate using Pt interdigitated electrodes (IDEs). The IDE spacing was 5 μm and deposition was performed using RF sputter with glancing angle deposition mode. Pt IDEs fabricated by photolithography and dry etching. In comparison with thin film sensor, sensing performance of nanostructure sensor showed an enhanced response of more than 20 times when exposed to 50 ppm acetone at 400°C. Such a remarkable faster response can pave the way for a new generation of exhaled breath analyzers based on chemiresistive sensors which are less expensive, more reliable, and less complicated to be manufactured. Moreover, presented sensor technology has the potential of being used as a personalized medical diagnostics tool in the near future.

All villi-like metal oxide nanostructures-based chemiresistive electronic nose for an exhaled breath analyzer

Moon, Hi Gyu,Jung, Youngmo,Han, Soo Deok,Shim, Young-Seok,Jung, Woo-Suk,Lee, Taikjin,Lee, Seok,Park, Jung Han,Baek, Seung-Hyub,Kim, Jin-Sang,Park, Hyung-Ho,Kim, Chulki,Kang, Chong-Yun Elsevier 2018 Sensors and actuators. B Chemical Vol.257 No.-

<P><B>Abstract</B></P> <P>Chemiresistive electronic nose (CEN) composed of villi-like nanostructures (VLNs) of SnO<SUB>2</SUB> and WO<SUB>3</SUB>, and Au-functionalized VLNs was fabricated by applying electron-beam evaporation in a glancing angle deposition mode. The VLNs-based CEN with a back-heater (212°C) shows high responses with low detection limits of parts per billion (ppb)-levels for NO and NH<SUB>3</SUB> vapors at 80% relative humidity atmosphere. The enhanced sensitivities in a high humidity condition turn out to be attributed to the spillover effect by the Au nanoparticles and a large surface-to-volume ratio in porous VLNs. Employing Au NPs on VLNs leads to the increase of O<SUP>−</SUP> ions via the spillover effect which impedes the adsorption of water molecules, maintaining the enhanced responses against environmental humidity. Consequently, high responses for NO and NH<SUB>3</SUB> vapors maintain even in the high humidity condition. Herein, with the principal component analysis (PCA), we demonstrate highly selective detection of NO and NH<SUB>3</SUB> vapors against C<SUB>2</SUB>H<SUB>5</SUB>OH, CO, C<SUB>7</SUB>H<SUB>8</SUB>, C6H6, and CH<SUB>3</SUB>COCH<SUB>3</SUB> vapors. These results open up wide applications of the VLNs-based CEN as an inexpensive and non-invasive diagnostic tool for asthma and kidney disorder.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A villi-like nanostructures (VLNs)-based chemiresistive electronic nose (CEN) as exhaled breath analyzer was developed. </LI> <LI> The VLNs-based CEN exhibits high sensitive detection to NO (Asthma) and NH<SUB>3</SUB> (Kidney disorder) as biomarkers. </LI> <LI> The detection limits (DLs) of the VLNs-based CEN are 899ppt–10.2ppb for NO and 312ppb–639ppb for NH<SUB>3</SUB>, respectively. </LI> <LI> The enhanced responses in humid environment are attribute to the spillover effect by Au nanoparticles. </LI> <LI> The highly selective NO and NH<SUB>3</SUB> detections were clearly distinguished by principal component analysis (PCA). </LI> </UL> </P>

Chemiresistive Electronic Nose toward Detection of Biomarkers in Exhaled Breath

Moon, Hi Gyu,Jung, Youngmo,Han, Soo Deok,Shim, Young-Seok,Shin, Beomju,Lee, Taikjin,Kim, Jin-Sang,Lee, Seok,Jun, Seong Chan,Park, Hyung-Ho,Kim, Chulki,Kang, Chong-Yun American Chemical Society 2016 ACS APPLIED MATERIALS & INTERFACES Vol.8 No.32

<P>Detection of gas-phase chemicals finds a wide variety of applications, including food and beverages, fragrances, environmental monitoring, chemical and biochemical processing, medical diagnostics, and transportation. One approach for these tasks is to use arrays of highly sensitive and selective sensors as an electronic nose. Here, we present a high performance chemiresistive electronic nose (CEN) based on an array of metal oxide thin films, metal-catalyzed thin films, and nanostructured thin films. The gas sensing properties of the CEN show enhanced sensitive detection of H2S, NH3, and NO in an 80% relative humidity (RH) atmosphere similar to the composition of exhaled breath. The detection limits of the sensor elements we fabricated are in the following ranges: 534 ppt to 2.87 ppb for H2S, 4.45 to 42.29 ppb, for NH3, and 206 ppt to 2.06 ppb for NO. The enhanced sensitivity is attributed to the spillover effect by Au nanoparticles and the high porosity of villi-like nanostructures, pioviding a large surface-to-volume ratio. The remarkable selectivity based on the collection of sensor responses manifests itself in the principal component analysis (PCA). The excellent sensing performance indicates that the CEN can detect the biomarkers of H2S, NH3, and NO in exhaled breath and even distinguish them clearly in the PC:A. Our results show high potential of the CEN as an inexpensive and noninvasive diagnostic tool for halitosis, kidney disorder, and asthma.</P>

기관지천식에서 Salbutamol 흡입이 환기기능 및 동맥혈의 산소분압에 미치는 영향

유덕종(Deok Jong Yoo),최정윤(Jung Yoon Choe),권삼(Sam Gweon),이원식(Won Sik Lee),정태훈(Tae Hoon Jung),박희명(Hi Myung Park) 대한내과학회 1987 대한내과학회지 Vol.33 No.4

N/A Effects of salbutamol inhalation were studied in 26 cases of bronchial asthma with particular reference to its main site of action in airways and influence on arterial oxygen tension (PaO2). In l7 cases out of 26, analy of forced expiratory volume and maximal expiratory flow volume curves were made before and 15 minutes after the drug administration, and in 9 of them, physiological dead space (VD/VT) and alveolar-arterial oxygen tension gradient (P(A-a)O2) were also determined 30 minutes after the medication. In the remaining 9 cases, serial determinations of PaO2 were made for 120 minutes following the drug inhalation. Salbutamol inhalation induced a significant improvement in almost all flow parameters and reduction in airway resistance. The alterations of PaO2 a whole, were inversely related to those of P(A-a)O2 whereas the changes in arterial carbon dioxide tension and VD/VT were variable. These facts suggest that in patients with bronchial asthma salbutamol inhalation improves large and small airways function and the changes in PaO2 is mainly results form the alteration of ventilation/perfusion ratio.

논문 : 초임계 CO2-시멘트 반응 전후의 투수율 및 강도 변화

이희권 ( Hi Kweon Lee ),김기덕 ( Ki Deok Kim ),김태희 ( Tae Hee Kim ),김교원 ( Gyo Won Kim ) 대한지질공학회 2016 지질공학 Vol.26 No.1

시멘트(KS-1 보통 포틀랜드와, Class G)을 이용하여, 시멘트-초임계CO2 반응실험과 반응 전/후 시료의 절대투수율 및 강도를 측정하였다. 시멘트 시료는 W/S (Water/Solid)와 fly ash 첨가량을 조절하여 제작하였다. 반응 전 시료의 투수율은 0.009~0.025mD, 초임계CO2와 100일간 반응 한 시료의 투수율은 0.11~0.29 mD의 범위로 각각 측정되었다. 반응 후 시료의 투수율이 높게 측정된 이유는, 반응 시료들이 겪은 응력해방으로 인해 균열이 발생하였기 때문이다. 그러나 측정된 투수율은 대부분의 시료에서 API가 추천하는 최대허용 투수율(=0.2 mD)보다 낮다. 초임CO2에 의한 시멘트 변질은 시료 전체가 아닌 시료의 가장자리에서 일정 두께로 시료의 내부로 발생하였다. 반응영역의 비커스 경도 값이 비반응영역의 것보다 훨씬 높게 측정되었다. 또한 대부분의 시료에서 반응영역 내에서 경도값이 증가한 후 감소하는 현상이 관찰 되었다. 경도값의 증가는 탄산화로 인한 밀도증가, 공극률 감소, 그리고 경도값 감소는 낮은 강도를 갖는 비정질 규산염수화물의 생성이 원인이다. Chemical reaction tests were performed to assess the properties of hardened specimens of cement pastes (KS-1 Portland and Class G) exposed to supercritical CO2 for 1, 10, and 100 days. After exposure, the samples’ measured permeability and strength were compared with values measured for pristine samples. The pristine cements had permeabilities of 0.009~0.025 mD, which increased by one order of magnitude after 100 days of exposure (to 0.11~0.29 mD). The enhancement of permeability is attributed to the stress release experienced by the samples after removal from the pressure vessel after exposure. Despite its enhancement, the measured permeability mostly remained lower than the API (American Petroleum Institute) recommended maximum value of 0.2 mD. The degradation of the cement samples due to exposure to supercritical CO2 led to a layer of altered material advancing inwards from the sample edges. The Vickers hardness in the altered zone was much higher than that in the unaltered zone, possibly owing to the increase in density and the decrease in porosity due to the carbonation that occurred in the altered zone. Hardness close to the edge within the altered zone was found to have decreased significantly, which is attributed to the conversion of C.S.H into less-strong amorphous silica.