• Title/Summary/Keyword: Sensor irradiation

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Fabrication of Hydrogel and Gas Permeable Membranes for FET Type Dissolved $CO_{2}$ Sensor by Photolithographic Method (사진식각법을 이용한 FET형 용존 $CO_{2}$ 센서의 수화젤막 및 가스 투과막 제작)

  • Park, Lee-Soon;Kim, Sang-Tae;Koh, Kwang-Nak
    • Journal of Sensor Science and Technology
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    • v.6 no.3
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    • pp.207-213
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    • 1997
  • A field effect transistor(FET) type dissolved carbon dioxide($pCO_{2}$) sensor with a double layer structure of hydrogel membrane and $CO_{2}$ gas permeable membrane was fabricated by utilizing a $H^{+}$ ion selective field effect transistor(pH-ISFET) with Ag/AgCl reference electrode as a base chip. Formation of hydrogel membrane with photo-crosslinkable PVA-SbQ or PVP-PVAc/photosensitizer system was not suitable with the photolithographic process. Furthermore, hydrogel membrane on pH-ISFET base chip could be fabricated by photolithographic method with the aid of N,N,N',N'-tetramethyl othylenediarnine(TED) as $O_{2}$ quencher without using polyester film as a $O_{2}$ blanket during UV irradiation process. Photosensitive urethane acrylate type oligomer was used as gas permeable membrane on top of hydrogel layer. The FET type $pCO_{2}$ sensor fabricated by photolithographic method showed good linearity (linear calibration curve) in the range of $10^{-3}{\sim}10^{0}\;mol/{\ell}$ of dissolved $CO_{2}$ in aqueous solution with high sensitivity.

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Infrared Signature Analysis on a Flat Plate by Using the Spectral BRDF Data (파장별 BRDF 데이터를 이용한 평판의 적외선 복사휘도 특성 분석)

  • Choi, Jun-Hyuk;Kim, Dong-Geon;Kim, Jung-Ho;Kim, Tae-Kuk
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.38 no.6
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    • pp.577-585
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    • 2010
  • This paper is a part of developing a software that predicts the infrared signal emitted from a ground object by considering solar irradiation. The radiance emitted from a surface can be calculated by using the temperature and optical characteristics of the surface object. The bidirectional reflectance distribution function (BRDF) is defined as the ratio of reflected radiance to incident irradiance. It is a very important surface reflection property that decides the reflected radiance from the object. In this paper, the spectral radiance received by a remote sensor over the mid-wave infrared(MWIR), and the long-wave infrared(LWIR) regions are computed and compared each other for several different materials. The results show that the optical surface properties such as the BRDF and the emissivity of the object surface can play a major role in generating the infrared signatures of various objects, and the largest infrared signal may reach up to 10 times the smallest one when the infrared signals obtained from a flat plate with different surface conditions under the sun light.

Effect of Ar Ion Irradiation on the Hydrogen Gas Sensitivity of SnO2 Thin Films (Ar 이온빔 조사에 따른 SnO2 박막의 물성 연구)

  • Heo, S.B.;Lee, Y.J.;Kim, S.K.;You, Y.Z.;Choi, D.H.;Lee, B.H.;Kim, M.G.;Kim, Daeil
    • Journal of the Korean Society for Heat Treatment
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    • v.25 no.6
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    • pp.279-282
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    • 2012
  • $SnO_2$ thin films were prepared on the Si substrate by radio frequency (RF) magnetron sputtering and then surface of the films were irradiated with intense Ar ion beam to investigate the effect of Ar ion irradiation on the properties and hydrogen gas sensitivity of the films. From atomic force microscope observation, it is supposed that intense Ar bombardments promote rough surface and increase gas sensitivity of $SnO_2$ films for hydrogen gas. The films that Ar ion beam irradiated at 6 keV show the higher sensitivity than the films were irradiated at 3 keV and 9 keV. These results suggest that the $SnO_2$ thin films irradiated with optimized Ar ion beam are promising for practical high-performance hydrogen gas sensors.

A Study of Gamma-ray Irradiation Effects on Commercially Available Single-mode Optical Fiber using Fiber Bragg Grating Sensor Systems (광섬유 브래그 격자 센서를 이용한 국내외 상용 단일모드 광섬유의 감마선 영향 연구)

  • Kim, Jong-Yeol;Lee, Nam-Ho
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.16 no.10
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    • pp.2287-2292
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    • 2012
  • In this study, $Co^{60}$ gamma-ray induced loss on Ge-doped single mode (SM) fiber has been measured. Gamma-ray is irradiated for 4 hours at the dose rate of 0.5 kGy/hr, 2 kGy/hr, 8 kGy/hr. Consequently, gamma-ray induced loss based on radiation effects in Ge-doped SM fiber occur significantly. Furthermore, dose rate effect was observed, that dose rate using the same total dose increased higher, then optical fiber loss increased more. Also annealing effect was observed, that the loss after irradiation, increased higher, then the recovery rate of loss was increased. This results are foreseen to be base data in the future radiation-hardened optical fiber study.

Fabrication and $^{60}Co$ Gamma Induced Damage of Plastic Scintillators (플라스틱 섬광체의 제작과 $^{60}Co$ $\gamma$-선에 의한 방사선 손상)

  • Kim, Sung-Hwan;Nam, Seung-Hee;Cheon, Jong-Kyu;Kim, Wan;Kang, Hee-Dong;Kim, Do-Sung;Lee, Woo-Gyo;Doh, Sih-Hong
    • Journal of Sensor Science and Technology
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    • v.9 no.5
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    • pp.350-356
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    • 2000
  • The optimum composition ratios of primary solute(p-terphenyl) and secondary solute(popop) have been investigated in order to fabricate plastic scintillator with higher light output and less radiation damage. The radiation damage induced by $^{60}Co$ $\gamma$-irradiation depends on mainly the concentration of secondary solute. The spectral range of the luminescence was $400{\sim}450\;nm$, its peak emission appeared at 415 nm. The transmittance and the light output were not changed by radiation damage up to $1{\times}10^4\;Gy$ irradiation with $^{60}Co$ $\gamma$-rays.

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Study on Basic Properties of Single Crystalline ZnO Nanowire (단결정 산화아연 나노선의 기초 물성 연구)

  • Ra, H.W.;Khan, R.;Kim, J.T.;Yeo, C.H.;Im, Y.H.
    • Journal of the Korean Vacuum Society
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    • v.18 no.4
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    • pp.259-265
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    • 2009
  • We fabricated the field effect transistor using single crystalline ZnO nanowires synthesized by a conventional thermal evaporation method and investigated their basic properties under the various conditions such as ultraviolet irradiation, reducing gas and electrolyte. The typical carrier concentration and mobility of the single crystalline ZnO nanowire with a diameter of 100 nm and length of 5 um were $1.30{\times}10^{18}cm^{-3}$ and $15.6cm^2V^{-1}s^{-1}$, respectively. The current of ZnO nanowire under ultraviolet irradiation significantly increased about 400 times higher as compared to in the darkness. In addition, the ZnO nanowire showed typical sensing characteristics for $H_2$ and CO due to well-known surface reactions and typical current-voltage characteristics under the 0.1 M NaCl electrolyte.

Heavy Metals Extraction from Contaminated Soils using Aqua Regia Extraction (왕수를 이용한 중금속 오염토양에서의 추출방안 연구)

  • Lee, Dukyoung;Jung, Sunkook;Son, Younggyu
    • Journal of Soil and Groundwater Environment
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    • v.23 no.2
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    • pp.15-22
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    • 2018
  • Aqua regia extraction for the quantification of heavy metals and As in contaminated soils was investigated as one of preliminary steps for on-site monitoring using sensor technology. Soil samples were taken from closed railway depot, closed mines, and closed refinery and various extraction conditions including $30^{\circ}C/15min$, $30^{\circ}C/30min$, $30^{\circ}C/60min$, $30^{\circ}C/120min$, $80^{\circ}C/15min$, $80^{\circ}C/30min$, $80^{\circ}C/60min$, $80^{\circ}C/120min$ were tested. The optimal extraction condition was determined as $80^{\circ}C/60min$ because the extraction efficiencies of Zn were relatively low and did not reach the targeted level (80-100% of original concentrations) for $30^{\circ}C$ conditions. It was found that the fractionation of heavy metals and As using the sequential extraction method was useful to understand the degree of metal extraction. In order to enhance the extraction efficiency within short extraction time, ultrasound technology using a 20 kHz horn-type sonicator was additionally used for $30^{\circ}C/15min$. It was revealed that ultrasound could significantly enhance the extraction efficiency and pulsed irradiation showed higher efficiency than continuous irradiation due to the less formation of bubble clouds. However high temperature condition ($80^{\circ}C$) was required to achieve high extraction efficiency for Zn in spite of the use of ultrasound.

Preparation of IPN-type Polyelectrolyte Films Attached to the Electrode Surface and Their Humidity-Sensitive Properties (전극 표면에 부착된 IPN 형태의 전해질 고분자의 제조 및 그들의 감습특성)

  • Han, Dae-Sang;Gong, Myoung-Seon
    • Polymer(Korea)
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    • v.34 no.6
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    • pp.565-573
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    • 2010
  • Copoly(2-(dimethylamino)ethyl methacrylate)(DAEMA)/butyl acrylate (BA) and copoly(methyl methacrylate)(MMA)/BA/2-(cinnamoyloxy)ethyl methacryate (CEMA), which were cross-linked with dibromoalkane and UV irradiation, respectively, were prepared for the precursors of interpenetrating polymer network (IPN) humidity-sensitive films. 3-(Triethoxysilyl)propyl cinnamate (TESPC) was used as a surface-pretreating agent for the attachment of IPN-polyelectrolyte to the electrode surface by UV irradiation. Humidity sensitive polymeric thin films with an IPN structure were prepared by crosslinking reactions of copoly(DAEMA/BA) with 1,4-dibromobutane (DBB) and copoly(MMA/BA/CEMA) by UV-irradiation. The anchoring of an IPN-polyelectrolyte into the substrate was carried out via the photochemical $[2{\pi}+2{\pi}]$ cycloaddition. The resulting humidity sensors showed a high sensitivity in the range of 20~95%RH and a small hysteresis (<1.5%RH). The response time for adsorption and desorption process at 33~94%RH was 48 and 65 s, respectively, indicating a fast response. The effects of the concentration of copolymers, molar ratio of crosslinking agents and time of the precursor solution for dip-coating on their humidity sensitive properties including water durability were investigated.

Effect of Electron-beam Irradiaton on the Artificial Bone Substitutes Composed of Hydroxyapatite and Tricalcium Phosphate Mixtures with Type I Collagen (수산화인회석과 인산삼칼슘 및 1형 콜라젠 혼합골의 전자빔 조사 효과)

  • Park, Jung Min;Kim, Soung Min;Kim, Min Keun;Park, Young Wook;Myoung, Hoon;Lee, Byung Cheol;Lee, Jong Ho;Lee, Suk Keun
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.35 no.1
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    • pp.38-50
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    • 2013
  • Purpose: The aim of this study is to evaluate the effect and potential of electron beam (E-beam) irradiation treatment to the synthetic bony mixtures composed of hydroxyapatite (HA; Bongros$^{(R)}$, Bio@ Co., Korea) and tricalcium phosphate (${\beta}$-TCP, Sigma-Aldrich Co., USA), mixed at various ratios and of type I collagen (Rat tail, BD Biosciences Co., Sweden) as an organic matrix. Methods: We used 1.0~2.0 MeV linear accelerator and 2.0 MeV superconductive linear accelerator (power 100 KW, pressure 115 kPa, temperature $-30{\sim}120^{\circ}C$, sensor sensitivity 0.1~1.2 mV/kPa, generating power sensitivity 44.75 mV/kPa, supply voltage $5{\pm}0.25$ V) with different irradiation dose, such as 1, 30 and 60 kGy. Structural changes in this synthetic bone material were studied in vitro, by scanning electron microscopy (SEM), elementary analysis and field emission scanning electron microscope (FE-SEM), attenuated total reflection (ATR), and electron spectroscopy for chemical analysis (ESCA). Results: The large particular size of HA was changed after E-beam irradiation, to which small particle of TCP was engaged with organic collagen components in SEM findings. Conclusion: The important new in vitro data to be applicable as the substitutes of artificial bone materials in dental and medical fields will be able to be summarized.

The Fabrication and Evaluation of HgI2 Semiconductor Detector as High Energy X-ray Dosimeter Application (고에너지 X선 선량계 적용을 위한 TiO2 첨가된 요오드화수은 반도체 검출기 제작 및 평가)

  • Choi, Il Hong;Noh, Sung Jin;Park, Jung Eun;Park, Ji Koon;Kang, Sang Sik
    • Journal of the Korean Society of Radiology
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    • v.8 no.7
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    • pp.383-387
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    • 2014
  • In this paper, for a new detection system development with the better accurate dose evaluation and beam distribution imaging using the small field irradiation of linear accelerator, the compound semiconductor based detection sensors were fabricated and the performance evaluation was investigated. The special particle-in-binder sedimentation was used for a large area film sensor fabrication. The detection properties for high energy x-rays were investigated from a dark current, an output current, a rising time, a falling time, and response delay measurement. The experimental results, the $TiO_2$ mixed $HgI_2$ sensor showed the best electrical characteristics than $PbI_2$, PbO, pure $HgI_2$. Linearity, repeatability, and accuracy tests from LINAC were tested, the $TiO_2$ mixed $HgI_2$ sensor showed the better performance than the commercially available dosimetry devices.