• Title/Summary/Keyword: Pb

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Rapid and Precise Determination of Pb Isotope Ratios Using Mu1ti-Collector ICP/MS (다검출기 유도결합 플라즈마 질량분석기를 이용한 신속하고 정밀한 Pb 동위원소 분석)

  • 최만식;정창식;신형선;임태선
    • The Journal of the Petrological Society of Korea
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    • v.10 no.3
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    • pp.157-171
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    • 2001
  • This study investigated the effects of Pb/Tl ratio, Pb concentration and concomitant matrix elements on the measurement of Pb isotope ratios using multi-collector ICP/MS (AXIOM MC model). Accuracy and reproducibility of Pb isotope ratios in NBS 981 solution were estimated for 42 data measured from March to August 2001. Pb isotopes measured in rocks, bronzes and sediments were compared to data measured by TIMS. Reproducibilities for $^{206}Pb/^{204}Pb,\; ^{207}Pb/^{204}Pb,\;and\;^{208}Pb/^{204}Pb$ ratio were about 500 ppm (2sd) and for $^{207}Pb/^{206}Pb$\;and\;^{208}Pb/^{206}Pb$ were 100~200 ppm for 200 ng of Pb in NBS 981 solution. The optimum conditions for the analysis of Pb isotope ratios with AXIOM MC for best accuracy and reproducibility were defined as follows; 1) Pb/Tl ratio is about 10 2) Pb concentration is about 100 ng/ml 3) correction for mass discrimination is performed by exponential law using 2.3887 of $^{205}Tl/^{203}Tl$ and Pb mass fractionation factor empirically obtained from $ln(^{208}Pb/^{206}Pb)-ln(^{205}Tl/^{203}Tl)$ relationship. The sample data measured with MC/ICP/MS for acid-digested and chemically separated rock samples, and acid-digested bronze samples and sediment samples coincide with those of TIMS within analytical errors. Therefore, MC/ICP/MS is a rapid analytical technique for Pb isotope ratios with the similar precision compared with TIMS.

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Pb-Pb Age of Marble from Muju, Korea (무주지역 대리암의 Pb-Pb 연대)

  • Park, Kye-Hun
    • The Journal of the Petrological Society of Korea
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    • v.5 no.1
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    • pp.84-88
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    • 1996
  • Pb isotope composition is analyzed from the rock chips of marbles intercalated between gneisses of Muju area and it shows very large variation ($^{206}Pb/^{204}Pb$=23.74~4142, $^{207}Pb/^{204}Pb$=16.32~18.43, $^{208}Pb/^{204}Pb$=36.42~39.75). The data points form well defined positive relationship on $^{206}Pb/^{204}Pb$ vs $^{207}Pb/^{204}Pb$ plot, which corresponds to $1.99{\pm}0.10$($2{\sigma}$) Ga. This age is very similar to the formation ages of the granitic gneisses from Buncheon and Cheondongri (Tanyang), and suggests that the fairly large volume of Sobaeksan Massif suffered regional metamorphism at this time. It is suggested that the most parts of Korean peninsula including Kyeonggi and Sobaeksan Massifs were very close each other and experienced a regional metamorphism together about 2.0 Ga ago from the fact that galenas from whole Korean Peninsula except Kyeongsang Basin and metamorphic rocks from Kyeonggi Massif also reveal a similar slope corresponding 2.0 Ga on Pb-Pb isotope plot.

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A Study on the Determinants of the Perceived Value and Preference toward the Private Brand of the Discount Store (할인점 PB제품에 대한 소비자의 지각적 가치와 선호도의 선행요인에 관한 연구)

  • Kim, Chong-Eui;Han, Dong-Yeo;Kim, So-Ree
    • Proceedings of the Korean DIstribution Association Conference
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    • pp.35-56
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    • 2006
  • The objective of this research is to identify the factors affecting the quality perception of consumer about the private brand and to investigate how the monetary utility of the private brand affects the consumer's preference. The main finding can be summarized in three points. The consumer's usage experience with PB have a positive but store image has no significant effect on the quality perception of PB. The perceived quality and monetary utility of PB has a significant effect on the quality perception while the perceived quality has stronger effect. The competitiveness of the national brand in the same store, post-usage attitude, the perceived quality, and perceived value have significant effect on the preference toward PB but monetary utility does not. The perceived effect has the strongest effect. This result suggests that even the value-seeking consumers prefer PB only when the perceived quality exceeds a certain limits. This study provides the strategic implications for retail managers and theoretical implication for the researcher studying PB.

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Effect of Dietary Selenium Levels on Antioxidative Defense System and Oxidative Damage of Liver Tissue in Lead Administered Rats (식이 Selenium 함량이 납중독 흰쥐 간조직의 항산화계와 세포 손상에 미치는 영향)

  • 임정교;이순재
    • Journal of the East Asian Society of Dietary Life
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    • v.11 no.4
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    • pp.259-267
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    • 2001
  • This study was to investigate the effect of selenium on hepatic antioxidative defense system and oxidative damage in lead-administered rats. Male Sprague-Dawley rats weighing 140$\pm$5g were divided into one normal group(Se, 0 ppm) and three lead groups according to dietary levels of selenium supplementation: Pb0(Se, 0 ppm), PbS(Se, 0.5 ppm), and PbSS(Se, 1.0 ppm). All experimental groups were fed the experimental diet ad libitum for 4 weeks, and lead groups fed one containing 2,000 ppm lead acetate. Liver superoxide dismutase(SOD) activities in Pb0 group increased compared with other experimental groups. Liver gluthathione peroxidase(GSH-px) activities in Pb0 group decreased compared with normal group, but those of PbS and PbSS groups significantly increased compared with Pb0 group. Glutathione S-transferase(GST) activities decreased in Pb0 group and not significantly different from PbS and PbSS groups compared with normal group. Reduced glutathione(GSH) contents and GSH/GSSG of liver in Pb0 group were lower than those of other groups. Liver vitamin E contents in Pb0 group were about 50% of the normal group, but those of PbSS and PbS increased more than Pb0 group. Liver damage in electron microphotography process decreased in RER, showed an increase in Iysosome and also an increase in swelling of mitochondria. and ordered as follows : PbSS. PbS. and Pb0. It was concluded that high levels of dietary selenium had protective effects on peroxidative damage of hepatic cell accompanied with increased antioxidative defense system in lead-administered rats.

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The Effect of Fe and Cu on the Pb Toxicity in Rats (Pb 중독에 Fe, Cu가 흰쥐의 체내에 미치는 효과에 관한 연구)

  • 김애정
    • Journal of Nutrition and Health
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    • v.26 no.6
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    • pp.743-757
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    • 1993
  • This study was undertaken to investigate the effects of dietary Fe and Cu levels on Pb accumulation of Pb poisoned rats. 80 male Sprague weaning Dawley rate weighing 80-90g were divided into 8 groups(Pb groups: LFLCPb-low Fe, low Cu and Pb group, LFACPB-low Fe, adequate Cu and Pb group, AFLCPb-adequate Fe, low Cu and Pb group, AFACPb-adequate Fe, adequate Cu and Pb group, without Pb gorups: LFLC-low Fe, low Cu and without Pb grooup, LFAC-low Fe, adequate Cu and without Pb group, AFLC-adequate Fe, low Cu and without Pb group, AFAC-adequate Fe, adequate Cu and without Pb group) according to Pb administration (0, 500ppm in drinking water) and Fe and Cu levels(Fe :6ppm, 40ppm, Cu : 0.5ppm, 0.8ppm) for 12 weeks. The food intake, body weight, gain, and FER of Pb groups were significantly lower than those of without Pb groups(p<0.01, p<0.001, p<0.001). The weights of liver in Pb groups were significantly lower than that of adequate Fe and Cu group in without Pb group(AFAC) (p<0.001). The Cu contents of liver in Pb groups were significantly lower than that of AFAC (p<0.01). The liver Pb accumulation of LFLCPb was significantly higher than those of LFACPb, AFLCPb, AFACPb(p<0.05). The serum Pb content of LFLCPb was significantly higher than those of LFACPb, AFLCPb, AFACPb(p<0.05). The levels of Hb, and Hct, of 12 weeks in Pb poisoned rats were lower than those of 8 weeks, in other words, long term Pb poisoned rats were affected more serious on hematoopoiesis. The fecal excretions of Fe and Cu in Pb groups were significantly higher than those of without Pb groups(p<0.001, p<0.001). The urinary Fe and Cu excretions were significantly higher than those of AFAC(p<0.001, p<0.001). There were significant differences between Pb groups and without Pb groups according to dietary Fe and Cu levels. So, dietary levels of adequate Fe and Cu were effective to reduce Pb accumulation in rats. It were showed that the decrease of food intake, FER, body weight gain, serum level of Fe and Cu in Pb groups than those of without Pb groups. And the increase of liver Pb accumulation, serum Pb levels, fecal and urinary Fe and Cu excretions were showed in Pb groups than those of without Pb groups by long term lead poisoning. Otherwise, adequate Fe and Cu administrations in Pb groups have preventive effects on the Pb poisoned rats.

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Effects of Mulberry Leaf Powder Supplementation on Lead Status and Minerals Content in Pb-administered Rats (뽕잎분말이 납 투여한 흰쥐 체내의 납과 무기질수준에 미치는 영향)

  • Kim Ae-Jung;Kim Myung-Hwan;Han Myung-Ryun
    • Journal of Nutrition and Health
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    • v.38 no.5
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    • pp.380-385
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    • 2005
  • This study was designed to investigate the effects of mulberry leaf powder supplementation on lead (Pb) status and mineral (Ca, Fe, Cu and Zn) content in Pb-administered rats for 4 weeks. Thirty two male rats were divided into 4 groups: a control, Pb, Pb5M (500 ppm $Pb + 5\%$ mulberry leaf powder), and Pb10M (500 ppm $Pb + 10\%$ mulberry leaf powder). There were no significant differences in food intake and initial body weight among groups. Mulberry leaf powder treatments showed significant decreases in food efficiency ratio and body weight gain. But FER of $Pb5M\%$ and Pb10M were significantly increases than that of Pb group. The levels of serum aspartate transaminase (AST) and creatinine were decreased by mulberry leaf powder treatment. Minerals content of liver and kidney were significantly decreased in the Pb groups than that of control group. Whereas, fecal minerals content were significantly increased in the Pb5M and Pb10M than those of control group. Pb content of serum, liver and kidney was significantly increased in the Pb group than those of control group. However, by mulberry leaf powder administration (Pb5M and Pb10M), Pb level of serum, liver and kidney were lowered than that of Pb group. And fecal Pb excretion was significantly increased in the Pb5M and Pb10M than that of Pb group. These results showed mulberry leaves were effective for lowing Pb accumulation in serum, organs, which may have potential to prevent Pb toxicity.

A study on the characteristics of low Pb Sn-5%Pb-1.5%Ag-x%Bi solder alloys (저Pb Sn-5%Pb-1.5%Ag-x%Bi계 솔더 합금의 특성에 관한 연구)

  • 홍순국;주철홍;강정윤;김인배
    • Journal of Welding and Joining
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    • v.16 no.3
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    • pp.157-166
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    • 1998
  • Recently as environmental pollution caused by Pb has posed a serious threat to the global environment, the trend to regulate the usage of Pb in electronic industry is one the rise. Currently, the solder alloy with high Pb content, Sn-37%Pb, is utilized in the electronic assembly therefore, the objective of this study is to develop an alternative solder alloy for the existing Sn-37%Pb solder alloy. First thing, this work choosed Sn-5%Pb-1.5%Ag, Sn-5%Pb-1.5%Ag-x%Bi(x=1~5%) for candidate solder alloys, and examined their properties such as melting range, wettability, microhardness, tensile property, oxidation behavior and microstructure. Wettability was on the same level of Sn-37%Pb. Dissolution of Pb ion in Sn-5%Pb solder was 0.46ppm. This solder alloy revealed cellular dendrite microstructure $\beta$-Sn matrix, Pb-rich phase, Ag/Sn, and Cu/Sn Intermetallic compounds. The range of solidification temperature was within 3$0^{\circ}C$. Also these alloy displayed higher tensile strength and lower elongation than Sn-37%Pb. The resistance of oxidation in Sn-5%Pb-1.5%Ag solder alloy was superior to that of Sn-37%Pb solder alloy. But that of Sn-5%Pb-1.5%Ag-5%Bi solder alloy was equal to that of Sn-37%Pb solder alloy.

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Distribution and Sources of Pb in Southern East/Japan Sea Sediments using Pb isotopes (동해 남부 해역 퇴적물에서 Pb동위원소를 이용한 Pb의 기원 추적 연구)

  • Choi Man Sik;Cheong Chang-Sik;Han Jeong Hee;Park Kye-Hun
    • Economic and Environmental Geology
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    • v.39 no.1
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    • pp.63-74
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    • 2006
  • In order to identify the Pb pollution and its sources in continental shelf and slope areas, Pb concentration and Pb isotope ratios ($^{207}Pb/^{206}Pb\;and\;^{208}Pb/^{206}Pb$) were determined far 6 box corer sediments collected from the southern East/japan Sea. Pb concentration, and $^{207}Pb/^{206}Pb\;and\;^{208}Pb/^{206}Pb$ ratios were constant at around $25\pm5 ppm$ and 0.842 and 2.092 from 1700 to 1930 year, respectively and increased steadily up to $40\pm5 ppm$ and 0.867 and 2.123 at the beginning of 1990s', respectively. The increase of concentration and isotope ratios in the labile fraction (leached by 2M HC1+0.5M $HNO_3$) explains their increase in bulk sediments, while Pb concentration and isotope ratios in the residual fraction were nearly constant during 300yrs. Temporal variation of Pb isotope ratios was explained by simple two end-members mixing of geo-genic and anthropogenic sources because isotope ratios and the inverse of Pb concentration showed the good linear relationships. Using Pb isotope ratios, we can constrain two Pb sources in the study area. The one is atmospheric particulates, compared with mean values of isotope ratios in atmospheric particulates collected at Jeju and Oki ;stands, based on the history of Pb emmission in Korea and China, and judged by oceanographic processes capable of homogenizing many sources. The other is local sources related to iron mills, refineries of Pb ore and of petroleum located at the coast of the study area. Isotope ratios of anthropogenic Pb can be estimated using two end-members mixing equation and were $0.879\pm0.005\;and\;2.144\pm0.008$ before 1950s' while they increased up to $0.900\pm0.008\;and\;2.162\pm0.011$ after 1980s', respectively.

PhaseTransformation of PbO-Precursor Prepared from Lead Nitrate (질산납으로부터 제조된 PbO-전구체의 산변태)

  • Choe, Byeong-Cheol;Lee, Mun-Ho
    • Korean Journal of Materials Research
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    • v.4 no.4
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    • pp.472-476
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    • 1994
  • Phase transformation of PbO-precursor prepared from $Pb(NO_{3})_{2}$ by precipitation technique was observed by TG-DTA, XRD, FT-IR, and Raman spectral analysis. PbO-precursor was derived from an aqueous solution of $Pb(NO_{3})_{2}$ at $45^{\circ}C$ and pH of 9.0. The precipitate showed it to be the mixture of hydrous lead oxynitrate and lead hydroxynitrate. With increasing heat-treatment temperature ranging up to $560^{\circ}C$, the precursor changed to $3Pb(NO_{3})_{2}$ . 7Pb0, $Pb(NO_{3})_{2}$. 5Pb0 and PbO(litharge), in turn. Finally, it transformed to massicot form of PbO above $560^{\circ}C$.

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The Effect of PbO on Sintering of Undoped PbTiO3 Ceramics Prepared by Sol-Gel Processing (PbO가 Sol-Gel Process로 제조된 순수 PbTiO3 세라믹스의 소결에 미치는 영향)

  • 김선욱;윤만순;김남흥
    • Journal of the Korean Ceramic Society
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    • v.29 no.5
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    • pp.335-340
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    • 1992
  • Undoped PbTiO3 ceramics was successfully prepared by using sol-gel process, which had not been fabricated due to its microcracks created by anisotropic stress during phase transition from cubic to tetragonal phase. Fabrication of undoped PbTiO3 ceramics via sol-gel processing was very much affected by the PbO content of the samples as well as PbO vapor from sintering atmosphere. Excess PbO was found to promote rapid grain growth in PbTiO3 ceramics. After sintering at 1100$^{\circ}C$ average grain size of PbTiO3 ceramics with excess PbO was about 8 times greater than that of stoichiometric composition, which may be due to PbO liquid phase from excess PbO.

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