• Title/Summary/Keyword: HgI2

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Fabrication and characteristics of Hybrid-type radiation detector using $HgI_2$ (혼합형 구조를 적용한 $HgI_2$ 기반의 방사선 센서 제작 및 특성)

  • Jang, K.Y.;Kang, H.G.;Lee, G.H.;Kim, S.Y.;Park, J.K.;Choi, H.K.;Nam, S.H.;Lim, J.K.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.11a
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    • pp.460-463
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    • 2004
  • 본 논문은 고에너지 방사선 검출을 위한 흔합형 구조의 방사선 센서를 제작, 반응 특성을 평가하였다. 먼저, 스크린 인쇄법을 이용하여 형광체 필름을 제작하였으며, 발광스펙트럼(PL, Photoluminescence) 및 잔광 시간(decay time) 측정을 통하여 형광체의 발광 특성을 조사하였다. 제작된 혼합구조의 방사선 센서는 $2{\mu}m$ 두께의 $HgI_2$$150{\mu}m$ 두께의 형광체 필름으로 제작되었으며, 면적은 $2\;cm\;{\times}\;2\;cm$이다. 방사선에 대한 전기적 검출 신호의 특성을 조사하기 위해 인가전압에 따른 암전류 및 방사선민감도, 선량에 따른 검출신호를 측정하였다. 측정결과, 제작된 $HgI_2$ 필름은 방사선에 의해 형광체에서 방출된 가시광 파장을 잘 흡수하였으며, 진단영역의 저에너지 방사선에 의해 직접 전기적 신호를 발생시켜 높은 방사선 민감도를 보였다. 뿐만 아니라, 인가전압에 대해 $10\;pA/mm^2$이하의 낮은 암전류를 가졌으며, 넓은 조사선량에서 우수한 선형성을 보였다.

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The Aquation of Co(Ⅲ) Complexes in Pure Water and Mixed Water-Organic Solvents With Hg$^{2+}$ (수용액 및 물-유기용매 혼합용매에서의 Hg$^{2+}$ 에 의한 Co(Ⅲ) 착물의 수화반응)

  • Oh Chang Eon;Yoon Doo Cheon;Doh Myung Ki
    • Journal of the Korean Chemical Society
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    • v.34 no.5
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    • pp.438-444
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    • 1990
  • Observed rate constants (k$_{obs.}$) for Hg$^{2+}$-catalysed aquation of cis-[Co(en)$_2$(OH$_2$)Cl]$^{2+}$, [Co(NH$_3$)$_5$Cl]$^{2+}$, cis-[Co(NH$_3$)$_4$(OH$_2$)Cl]$^{2+}$, and [Co(NH$_2$CH$_3$)$_5$Cl]$^{2+}$ were measured at various concentrations of Hg$^{2+}$. The k$_{obs.}$ was increased with increasing the concentrations of Hg$^{2+}$. The k$_{obs.}$ were related to mechanistically derived rate constants by the relationship; Rate = k$_2$K[complex][Hg$^{2+}$]. Various mixed aqueous-organic solvent have been successfully employed for Hg$^{2+}$-catalysed aquation of octahedral myetal complexes. From the slope of the plot of log k againt Y (solvent ionizing power), the mechanism on the aquation of Co(Ⅲ) complexes by Hg$^{2+}$ has been suggested to be I$_d$-mechanism. The change in a rate on aquation of each Co(Ⅲ) complex was related to the ligand field parameters (${\Delta}$), for Co(Ⅲ) complexes.

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입자침전법을 이용한 광도전체 필름의 X선 반응 특성에 관한 연구

  • Choe, Chi-Won;Gang, Sang-Sik;Jo, Seong-Ho;Gwon, Cheol;Nam, Sang-Hui
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2007.06a
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    • pp.176-176
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    • 2007
  • Flat-panel direct conversion detectors used in compound substance of semiconductor are being studied for digital x-ray imaging. Recently, such detectors are deposited by physical vapor deposition(PVD) generally. But, most of materials (HgI2, PbI2, TlBr, PbO) deposited by PVD have shown difficult fabrication and instability for large area x-ray imaging. Consequently, in this paper, we propose applicable potentialities for screen printing method that is coated on a substrate easily. It is compared to electrical properties among semiconductors such as $HgI_2$, $PbI_2$, PbO, HgBrI, InI, and $TlPbI_3$ under investigation for direct conversion detectors. Each film detector consists of an ~25 to $35\;{\mu}m$ thick layer of semiconductor and was coated onto the substrate. Substrates of $2cm{\times}2cm$ have been used to evaluate performance of semiconductor radiation detectors. Dark current, sensitivity and physics properties were measured. Leakage current of $HgI_2$ as low as $9pA/mm^2$ at the operation bias voltage of ${\sim}1V/{\mu}m$ was observed. Such a value is not better than PVD process, but it is easy to be fabricated in high quality for large area x-ray Imaging. Our future efforts will concentrate on optimization of growth of film thickness that is coated onto a-Si TFT array.

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Fabrication and Characterization of Polycrystalline Mereuric Iodide Films using Particle-in-Binder Methods (Particle-in-Binder(PIB) 법을 이용한 다결정 $HgI_2$ 필름 제작 및 특성 연구)

  • Cha, Byung-Youl;Cho, Sung-Ho;Kim, So-Yeong;Woon, Min-Seuk;Nam, Sang-Hee
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2007.06a
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    • pp.330-330
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    • 2007
  • Polycrystalline mercuric iodide $HgI_2$) films are being developed as a new detector technology for digital x-ray imaging. The $HgI_2$ is generally vacuum deposited by physical vapor deposition (PVD) process. But the PVD thick deposition has been caused any instability in the biasing due to any defects or cracks. In this work we present a new particle-in-binder (PIB) methodologies used for the $HgI_2$ thick films. These growth techniques can be easily extended to produce much larger film areas. This paper, for the first time, presents results and comparison of polycrystalline $HgI_2$ films derived by various PIB methods. We investigated the structural and morphological properties of the films using X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis. The films were characterized with respect to their electrical properties and in response to x-ray photons. Physical and electrical results were also compared between conventional polycrystalline PVD and our detectors. Leakage current as low as $350\;pA/cm^2$ at the bias voltage of ~ 200 V has been observed. And high sensitivity and good linearity in the response to x-rays was obtained in the film derived by PIB sedimentation method. Our future efforts will concentrate on optimization of film growth techniques for uniform large area deposition on image readout arrays.

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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.

Comparison of Toxic Effects of Mercury, Copper and Zinc on Photosystem II of Barley Cholroplasts (보리 엽록체의 광계 II에서 수은, 구리 및 아연의 저해효과 비교)

  • 전현식
    • Journal of Plant Biology
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    • v.36 no.3
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    • pp.195-201
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    • 1993
  • The room temperature fluorescence induction of chloroplasts was utilized as a probe to locate the site of inhibition by mercury, copper and zinc on PS II by mercury. Inhibitory effect of Hg2+ on electron transport activity was notable as compared with Cu2+ and Zn2+. At concentrations of HgCl2 over 50 $\mu$M, activities of PS II and whole-chain electron transport decreased more than 70%, while that of PS I decreased about 10~30%. This suggests that PS II is more susceptible to Hg2+ than PS I is. In the presence of diphenylcarbazide (DPC), 50 $\mu$M HgCl2 inhibited the reduction of dichlorophenolindophenol (DCPIP) about 50%. Addition of heavy metals induced marked decrease in maximal variable fluorescence/initial fluorescence [(Fv)m/Fo], but no changes in Fo. With various concentrations of heavy metals, changes of chlorophyll a fluorescence emitted by PS II showed gradual decrease in photochemical quenching (qQ), which indicates an increase in reduced state of electron acceptor, QA. Especially, the addition of HgCl2 caused a notable decrease of qQ. In the presence of 50 $\mu$M CuCl2, energy-depended quenching (qE) was completely reduced, whereas in the presence of 50 $\mu$M CuCl2 and ZnCl2 it was still remained. The above results are discussed on the effects of mercury in relation to water-splitting system and plastoquinone (PQ) shuttle system.

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Studies on the Harmful Heavy Metal of Food Stuff( I ) -Contents of Hg in edible Bean Sprouts- (식품중(食品中) 유해성중금속(有害性重金屬)에 관(關)한 연구(硏究) ( I ) -콩나물중의 수은 정량-)

  • Park, Jae-Hong;Nam, Hyun-Keun
    • Journal of Nutrition and Health
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    • v.10 no.3
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    • pp.7-9
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    • 1977
  • Quantitative analysis of harmful Hg in edible bean sprouts was carried out by the Atomic Absorption Spectrophotometer (Perkin-Elmer Model 403). The samples studied as shown in Table 2. are edible bean sprouts (36) which wet·e collected from Gwangju area. It was investigated that the Mercury (Hg) content of edible bean sprouts was from 0.0098 ppm to 0.533 ppm (average 0.240). Mercury contaminated edible bean sprouts studied, was about 50 percentage of total samples.

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Characterization of Two Cryptic Plasmids from Levilactobacillus zymae GU240

  • Le, Huong Giang;Kim, Min Jae;Jeon, Hye Sung;Yoo, Ji Yeon;Kang, Yun Ji;Kim, Tae Jin;Kim, Jeong Hwan
    • Microbiology and Biotechnology Letters
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    • v.50 no.1
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    • pp.63-70
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    • 2022
  • Two small cryptic plasmids, pHG1 and pHG2, were isolated from Levilactobacillus zymae (formerly Lactobacillus zymae) GU240 and characterized. pHG1 is 1,814 bp in size with a GC content of 37.4% and contains two open reading frames. orf1 can potentially encode a protein of 101 amino acids (aa) with 99% identity with the copy number control protein of Lacticaseibacillus paracasei. orf2 can potentially encode a protein of 230 aa with 99% identity with a replication protein from multiple species. Six inverted repeats (IR I-VI) and six direct repeats (DR I-VI) were found in pHG1. pHG2 is 2,864 bp in size, with a GC content of 39.6%. pHG2 has two orfs. orf1 might encode a protein with 99% identity with the TrsL transmembrane protein. orf2 might encode a protein with 99% identity with plasmid recombination proteins from lactic acid bacteria. Both pHG1 and pHG2 may be useful as frames for constructing lactic acid bacteria-Escherichia coli shuttle vectors.

Study on self-diffusion transport phenomena during mercurous bromide (Hg2Br2) vapor processes (브로민화수은(I)(Hg2Br2) 증착공정에서 자체확산 연구)

  • Nam Il Kim;Geug Tae Kim
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.34 no.2
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    • pp.48-54
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    • 2024
  • During the Hg2Br2 physical vapor transport process with self-diffusion, it is concluded that for 10-3g0≤ g ≤ 1g0 the thermal buoyancy driven convection is dominant in the vapor phase; at the gravitational level of g = 10-4g0, the transition region from the convection to diffusion occurs; for 10-6g0 ≤ g ≤ 10-5g0, the diffusion mode is predominant. The total molar flux of Hg2Br2 decays exponentially with the decreasing of one tenth of gravitational magnitude. For 10℃ ≤ ΔT ≤ 50℃, the total molar flux increases linearly and directly with the temperature difference between the source and crystal regions.