• 제목/요약/키워드: PbI2

검색결과 519건 처리시간 0.03초

Influence of Surface area, Surface Chemical Structure and Solution pH on the Adsorption of Pb(II) Ions on Activated Carbons

  • Goyal, Meenakshi;Amutha, R.
    • Carbon letters
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    • 제7권2호
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    • pp.97-104
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    • 2006
  • The influence of carbon surface area, carbon-oxygen groups associated with the carbon surface and the solution pH on the adsorption of Pb(II) ions from aqueous solutions has been studied using three activated carbons. The adsorption isotherms are Type I of BET classification and the data obeys Langmuir adsorption equation. The BET surface area has little effect on the adsorption while it is strongly influenced by the presence of acidic carbon oxygen surface groups. The amount of these surface groups was enhanced by oxidation of the carbons with different oxidizing agents and reduced by eliminating these groups on degassing at different temperatures. The adsorption of Pb(II) ions increases on each oxidation and decreases on degassing the oxidized carbons. The increase in adsorption on oxidation has been attributed to the formation of acidic carbon-oxygen surface groups and the decrease to the elimination of these acidic surface groups on degassing. The adsorption is also influenced by the pH of the aqueous solution. The adsorption is only small at pH values lower than 3 but is considerably larger at higher pH values. Suitable mechanisms consistent with the adsorption data have been suggested.

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QFP 솔더접합부의 크립특성에 관한 연구 (A Study on the Creep Characteristics of QFP Solder Joints)

  • 조윤성;최명기;김종민;이성혁;신영의
    • 한국공작기계학회논문집
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    • 제16권5호
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    • pp.151-156
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    • 2007
  • In this paper, the creep characteristics of lead and lead-free solder joint were investigated using the QFP(Quad Flat Package) creep test. Two kind of solder pastes(Sn-3Ag-0.5Cu, Sn-0.2Sb-0.4Ag-37.4Pb) were applied to the QFP solder joints and each specimen was checked the external and internal failures(i.e., wetting failure, void, pin hole, poor-heel fillet) by digital microscope and X-ray inspection. The creep test was conducted at the temperatures of $100^{\circ}C$ and $130^{\circ}C$ under the load of 15$\sim$20% of average pull strength in solder joints. The creep characteristics of each solder joints were compared using the creep strain-time curve and creep strain rate-stress curves. Through the comparison, the Sn-3Ag-0.5Cu solder joints have higher creep resistance than that of Sn-0.3Sb-0.4Ag-37.4Pb. Also, the grain boundary sliding in the fracture surface and the necking of solder joint were observed by FE-SEM.

태백산광화대내의 원동 다금속광상의 성인 (Ore Genesis of the Wondong Polymetallic Mineral Deposits in the Taebaegsan Metallogenic Province)

  • 황덕환;이재영
    • 자원환경지질
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    • 제31권5호
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    • pp.375-388
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    • 1998
  • The purpose of this study is to investigate the ore genesis and occurrence of the Wondong polymetallic mineral deposits. The Pb-Zn, Fe and W-Mo mineralizations are found in skarn zones which formed mainly in or along the fault shear zones with the $N25-40^{\circ}W$ and $N10-50^{\circ}E$ directions, whereas the Cu-Mo mineralization is appeared hydrothermal replacement zone. The skarn minerals consist mainly of garnet and epidote, which were the last alteration phases between pneumatolytic and hydrothermal stages. The mineral paragenesis toward the late stage are as follows: arsenopyrite, scheelite, magnetite, pyrite, pyrrhotite, sphalerite, galena, chalcopyrite and molybdenite. Average ore grades are 0.33 g/t Au, 46.29 g/t Ag, 0.06% Cu, 4.4% Pb, 2.61% Zn and 29.39% Fe in tunnels, and 0.31 % Cu, 0.52% Pb, 6.29% Zn, 29.29% Fe, 0.03% Mo and 0.12% $WO_3$ in drill cores. Fluid inclusion data shows that Type I (liquid-rich), Type II (vapor-rich) and Type III (halite-bearing) inclusions are coexisted and their homogenization temperatures are quite similar. This indicates that boiling conditions have been reached during the mineralization. It is also likely that the ore solutions were evolved through the mixing between magmatic and meteoric waters. Rhyolite and quartz porphyry far the mineralization probably are not responsible of the Wondong polymetallic mineral deposits.

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폴리에틸렌 미세플라스틱과 납의 복합노출에 따른 실험동물의 세포면역기능 조절 장애 평가 (Dysregulation of Cellular Immune Functions on Gastric Administration to Mixtures of Polyethlene Microplastics and Metallic Lead in Mice)

  • 이경우;김창열
    • 한국환경보건학회지
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    • 제49권1호
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    • pp.22-29
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    • 2023
  • Background: The existing research results on the combined toxicity of these pollutants using mammals, such as rodents, are insufficient, especially in relation to changes in the immune system. Objectives: This study aims at evaluating the cellular immune response to PE-MPs solely or when combined with Pb, which possess excellent adsorption capacity with PE-MPs and is commonly co-exposed in our daily lives. Methods: The study investigated the cellular immune function of 9-week ICR mice with 28 days exposure to PE-MPs (2 mg/mouse/day) and Pb (0.1 mM in distilled water) individually and in combination. PE-MPs were administered via gastric intubation while the lead intake was conducted via the oral drinking water route. Cellular immunity was evaluated by analyzing the production for TH1 cytokines namely, TNF-α and IFN-𝛾 and TH2 cytokines, IL-4 and IL-6 in culture supernatants from polyclonally activated splenic mononuclear cells ex vivo. Results: Both the PE-MPs only and the PE-MPs+Pb exposure group revealed an increased TH1 response with elevated TNF-α and IFN-𝛾 levels and downregulated TH2 response with low IL-4, and IL-6 production levels compared to the control group. Furthermore, an increased IFN-𝛾/IL-4 ratio was found in the PE-MPs only and PE-MPs+Pb exposure groups, which indicated the skewedness to TH1 response. Meanwhile, reduced blood hemoglobin levels and increased levels of IL-4, the dominant TH2 cytokine in the Pb-only exposure group, were observed. Conclusions: Our current findings on the predominance of TH1 immune response in the PE-MPs and PE-MPs+Pb groups suggest that PE-MPs could be responsible for the predominant induction of the cellular immune changes. This finding could be used as an important landmark in research related to TH1 predominance, such as autoimmune diseases. It suggests that additional research on immune modulation using longer exposure durations or the same exposure route is required to elucidate stronger findings.

TSDC 방법을 이용한 AC 폴링된 PMN-PT 단결정의 디폴링 메커니즘 분석 (Depolarization Mechanism of Alternating-current-poled Pb(Mg1/3Nb2/3)O3-PbTiO3 Single Crystals Measured using in-situ thermally Stimulated Depolarization Current)

  • 이건주;김황필;이상구;이호용;조욱
    • 센서학회지
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    • 제29권1호
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    • pp.59-62
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    • 2020
  • Currently, increasing attention is being paid to relaxor-based ferroelectric single crystals in photoacoustic images, especially for high-end applications. Among the crystals are (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-100xPT) single crystals located near their morphotropic phase boundary (x = 0.30-0.35) because of their ultrahigh piezoelectric and electromechanical coupling properties. The alternating current poling (ACP) treatment, rather than the conventional direct current poling treatment, has recently been spotlighted due to its effectiveness in enhancing the piezoelectric properties. So far, it has been suggested that the enhanced piezoelectricity originates from either a domain miniaturization to nanodomains or from an electric-field-induced monoclinic symmetry. In this study, we demonstrate by thermally stimulated depolarization current measurements that the effect of ACP is too complex to be explained using a single mechanism and that the proposed electric-field-induced monoclinic symmetry is unlikely to exist.

시험연소결과에 근거한 플라즈바 아크방식 유리화 시험 설비의 제염성능 평가(I) - 배기가스중의 유해중금속, 방사성핵종 모의물질 및 방사성핵종 제염특성 - (Decontamination Performance Assessment for the Plasma Arc Vitrification pilot plant on the basis of Trial Burn Results(I) - Decontamination Characteristics for Hazardous Metal, Radioactive surrogate and Radioactive Tracer in Off-gas)

  • 채경선;박윤환;민병연;장재옥;박준용;정원익;문병식
    • Journal of Radiation Protection and Research
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    • 제25권2호
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    • pp.99-107
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    • 2000
  • 플라즈마 아크 용융방식 유리화 시험설비의 계통내 기체 및 최종배출구 전단의 배기체를 분석함으로써 배기체중에 포함된 분석용 첨가물의 거동 및 배기가스 처리장치의 제염성능을 평가하였다. 중금속 물질(Pb, Cd, Hg), 방사성 모의물질(Co, Cs) 그리고 방사성핵종($^{60}Co,\;^{137}Cs$)을 분석용 첨가물로 사용한 실험결과로부터 첨가물질의 거동에 따른 유리화 설비 배기체처리시스템의 제염특성 및 제염제수를 구하였다.

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도로변 우수관 퇴적물의 중금속오염 (I) : 서울시 동부지역 (The heavy metal contaminations of sediments from some gully-pots : eastern part of seoul, Korea)

  • 이평구;김성환;윤성택
    • 한국지하수토양환경학회지:지하수토양환경
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    • 제6권4호
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    • pp.25-40
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    • 2001
  • 중금속오염 정도를 조사하기 위해, 서울시 동부의 13개 구에서 280개 우수관퇴적물을 채취하였다. 오염되지 않은 하천 표사시료도 비교하기 위해 연구되었다. 퇴적물의 물리화학적 특성과 Cd, Co, Cr, Cu, Ni, Pb, 및 Zn 분포에 관한 연구가 수행되었다. 우수관퇴적물과 오염되지 않은 표사시료의 총 중금속 함량은 산분해방법을 이용하여 분석하였다. 먼저 질산으로 분해한 뒤, 다시 질산과 과염소산의 혼합산으로 산분해하였다. 우수관퇴적물은 특징적으로 Zn, Cu, Pb및 Cr함량이 매우 높았으며, 이는 우수관퇴적물이 이들 원소에 의해 인위적으로 오염된 것을 지시하고 있다. 우수관퇴적물에 포함된 중금속 함량은 오염되지 않은 하천 표사시료의 평균 중금속 함량에 비해 원소에 따라 약 1-329배 높게 나타났다. 특히, 가장 높은 Zn, Cu, Pb 및 Cr평균값을 나타낸 지역은 각각 여의도, 중구, 중구 및 동대문구에서 채취한 우수관퇴적물이었다. 비즈니스 지역과 상업지역에서의 평균 Zn 함량은 산업공단지역의 Zn 함량보다 2-305배 높다. 이것은 Zn이 주로 자동차 교통량(자동차 타이어)에서 기인된 것을 지시한다. 평균 Cu와 Cr의 함량은 상업지역과 산업공단지역에서 높게 나타났으며, 이는 산업활동이 우수관퇴적물에 Cu와 Cr 축적을 야기시키고 있다는 것을 지시하고 있다. 우수관퇴적물의 Pb 함량은 비교적 낮았으며, 이는 1987년 이후 무연휘발유를 사용하는 것에 기인하였다.

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Chemical Properties of Indoor Individual Particles Collected at the Daily Behavior Spaces of a Factory Worker

  • Ma, Chang-Jin;Kang, Gong-Unn;Sakai, Takuro
    • Asian Journal of Atmospheric Environment
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    • 제11권2호
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    • pp.122-130
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    • 2017
  • The main purpose of the study was to clarify the properties of individual particles collected at each behavior space of a factory worker. The samplings of size-segregated ($PM_{2.1-1.1}$ and $PM_{4.7-3.3}$) indoor particles were conducted at three different behavior spaces of a factory worker who is engaged in an auto parts manufacturing plant (i.e., his home, his work place in factory, and his favorite restaurant). Elemental specification (i.e., relative elemental content and distribution in and/or on individual particles) was performed by a micro-PIXE system. Every element detected from the coarse particulate matters of home was classified into three groups, i.e., a group of high net-counts (Na, Al, and Si), a group of intermediate net-counts (Mg, S, Cl, K, and Ca), and a group of minor trace elements (P, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, and Pb). The results of EF for $PM_{4.7-3.3}$ in home indicated that several heavy metals were generated from the sources within the house itself. An exceptional feature shown in the individual particles in workplace is that Cr, Mn, and Co were clearly detected in both fine and coarse particles. Cluster analysis suggested that the individual coarse particles ($PM_{4.7-3.3}$) collected at the indoor of factory were chemically heterogeneous and they modified with sea-salt, mineral, and artificially derived elements. The principal components in individual coarse particles collected at restaurant were sea-salt and mineral without mixing with harmful trace elements like chromium and manganese. Compared to the indoor fine particles of home and restaurant, many elements, especially, Cl, Na, Cr, Mn, Pb, and Zn showed overwhelmingly high net-counts in those of factory.

실시간 XRD와 TEM을 이용한 MAPbI3의 온도 변화에 따른 구조 분석 (Investigation of Electron Thermally Induced Phase Transition in MAPbI3 Perovskite Solar Cells Using In-Situ XRD and TEM)

  • 최진석;엄지호;윤순길
    • 한국전기전자재료학회논문지
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    • 제32권1호
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    • pp.64-69
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    • 2019
  • Methylammonium lead triiodide ($MAPbI_3$)-based perovskite solar cells potentially have potential advantages such as high efficiency and low-cost manufacturing procedures. However, $MAPbI_3$ is structurally unstable and has low phase-change temperatures ($30^{\circ}C$ and $130^{\circ}C$); it is necessary to solve these problems. We investigated the crystal structure and phase separation using real-time temperature-change X-ray diffraction, transmission electron microscopy, and electron energy loss spectroscopy. $MAPbI_3$ has a tetragonal structure, and at about $35^{\circ}C$ the c-axis contracts, transforming $MAPbI_3$ into the related cubic crystal structure. In addition, at $130^{\circ}C$, phase separation occurs in which $CH_3NH_2$ and HI at the center of the unit cell of the perovskite structure are extracted by gas, leavingand only $PbI_2$ of the three-component structure, is produced as the final solid product.

아연광산(亞鉛鑛山) 주변(周邊) 토양중(土壤中) 카드뮴, 아연(亞鉛), 구리 및 연(鉛) 화학적(化學的) 형태별(形態別) 함량(含量) (Sequential Extraction of Cadmium, Zinc, Copper and Lead in Soils near Zinc-mining Sites)

  • 유순호;김계훈;현해남
    • 한국환경농학회지
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    • 제4권2호
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    • pp.71-77
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    • 1985
  • 아연광산(亞鉛鑛山) 주변(周邊)에서 답토양(畓土壤)과 현미(玄米) 36점을 채취(採取)하여 축차분별분석(逐次分別分析)에 의해 토양(土壤) 중(中) Cd, Zn, Cu 및 Pb의 각(各) 형태별(形態別) 함량비(含量比)를 구하고, 중금속(重金屬)의 형태(形態)에 미치는 토양(土壤) 특성(特性)과 수도(水稻)의 흡수(吸收)와 관계가 깊은 화학적(化學的) 형태(形態)를 밝히기 위해 실험(實驗)하였다. 토양(土壤) 중(中) Cd의 형태별(形態別) 함량(含量)은 치환태(置煥態), 유기태(有機態) 및 carbonate 태가(態) 거의 같았으며 전(全) Cd의 73.9%를 차지하였다. 토양 중(中) Zn,은 잔류성(殘留性) Zn이 63.8%로 가장 높았다. Cu와 Pb의 형태별(形態別) 함량비(含量比)의 순위(順位)는 비슷하였다. 토양(土壤)의 pH가 높을수록 치환태(置換態) Cd, Zn, 및, Pb는 감소(減少)하였으며, 유기태(有機態)와 carbonate 태(態), Cd, sulfide 태(態) Cd, Zn, 및 Pb는 증가(增加)했다. 토양(土壤) 중(中) 유기물함량(有機物含量)은 유기태(有機態) Cd, Zn, 및, Pb는 carbonate 태(態) Cu와 정(正)의 상관(相關)을 보였다. 양(陽)이온치환용량(置換容量)이 증가(增加)하면 치환태(置換態) Cd, Zn, Cu 및, Pb, 유기태(有機態) Cu는 감소(減少)하였으나 carbonate 태(態) Cd, sulfide 태(態) Cd, Zn, Cu 및, Pb, 잔류성(殘留性) Cu는 증가(增加)하였다. 현미(玄米) 中 Cd 함량(含量)은 토양(土壤) 중(中) 전(全) Cd, 유기태(有機態) Cd, carbonate 태(態), sulfide 태(態) Cd 및 잔류성(殘留性) Cd와 높은 정(正)의 상관(相關)을 보였다. 그러나 토양(土壤) 중(中) Pb는 어떠한 형태(形態)도 현미(玄米) 중(中) Pb 함량(含量)과 상관(相關)이 없었다. 토양(土壤) 중(中) 수용태(水溶態)와 치환태(置換態) Zn 함량(含量)은 현미(玄米) 중(中) Zn 함량(含量)과 높은 정(正)의 상관(相關)을 보였다.

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