• Title/Summary/Keyword: Characteristics of PB

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Size Characteristics of Lead Particles Generated in Four Industries

  • Park, Dong-Uk;Paik, Nam-Won;Chung, Moon-Ho
    • Journal of Environmental Health Sciences
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    • v.28 no.4
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    • pp.12-16
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    • 2002
  • Workers' exposure to lead particles with diverse characteristics was assessed using personal cascade impactors in four different industries. Correlation analyses found that total airborne lead (PbA) concentrations could not explain the variation on MMAD of lead particles. From regression analysis, the concentrations of lead particles smaller than 1 um in AD were found to rise very slowly with increases in total PbA. They rarely contributed more than 50 ㎍/㎥ of total PbA over the range of 5.6-7,740 ㎍/㎥ although there are a few high values greater than 100 ㎍/㎥ while respirable lead concentrations significantly increased with increasing total PbA concentrations. In the secondary smelting and radiator manufacturing industries requiring high temperatures, the average fraction of respirable concentration in total PbA was 43.3% and 48.9%, respectively, which indicated an important contribution to the total PbA. In lead powder and battery manufacturing, it was less than 27%. Our study results concluded that workers' exposure to lead particles with diverse characteristics might not be effectively monitored by the current total PbA sampling alone. To protect workers exposed to different sizes of lead particles generated in many operations, an occupational standard for respirable lead particles should be added to the current total lead standard.

Effect of Excess PbO Addition on Sintering and Piezoelectric Characteristics in Pb(Ni1/3Nb2/3)O3-PbTiO3-PbZrO3 System (PbO 과잉량이 Pb(Ni1/3Nb2/3)O3-PbTiO3-PbZrO3계의 소결 및 압전특성에 미치는 영향)

  • 전구락;김정주;조상희;김도연
    • Journal of the Korean Ceramic Society
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    • v.26 no.4
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    • pp.568-574
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    • 1989
  • Effect of PbO addition on sintering and piezoelectric properties at 0.45Pb(Ni1/3Nb2/3)O3-0.40PbTiO3-0.15PbZrO3 composition which is tetragonal phase was investigated. In this composition, Porosity and dielectric constant were increased with excess PbO addition, but Kp and d31 was not changed. These variation of physical properties could be interpreted as composition change of solid grains from tetragonal to MPB region due to amount of PbO-rich liquid changing.

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Effects of pH and the Existence of CO2 Gas on the Silica Surface Characteristics at Silica/Pb(II) Solution Interface (CO2 가스의 존재 여부와 용액의 pH가 Silica/Pb(II) 용액 계면에서 Silica 표면의 특성에 미치는 영향)

  • Lee, Sang-Eun
    • Korean Journal of Soil Science and Fertilizer
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    • v.36 no.5
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    • pp.263-271
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    • 2003
  • Effects of the existence of $CO_2$ gas and pH on the silica surface characteristics at silica/Pb(II) and sodium dodecyl sulfonate (SDS, $C_{12}H_{25}SO_3Na$) solution interface were studied. The hydrophobic characteristics of silica surface was delineated by contact angle measurement and surface force measurement using atomic force microscopy (AFM). In $CO_2$ free condition provided by purging $N_2$ gas, the contact angle of fused silica surface in $10^{-4}M$ Pb(II) and SDS solution increased greatly up to $90^{\circ}$ compared with $40^{\circ}$ in atmospheric condition. It was due to the precipitation of $PbCO_3$ in atmospheric condition. In $CO_2$ free condition the change of contact angle and adhesion force ($F_{ad}$) in AFM, affected by pH change, was similar to the distribution of $PbOH^+$ ion in speciation diagram corresponding to $10^{-4}M$ total Pb(II). Therefore, it was convinced that the $PbOH^+$ ion among Pb(II) species would be the main adsorbing type on silica surface. Both of contact angle measurement and surface force measurement using AFM showed that the Pb only treatment made the silica surface hydrophobic. However, it could not be explained theoretically by current knowledge, and required further study in atomic level to solve the problem.

A study on the characteristics of Pb free Sn-2%Ag-x%Bi solder alloys (Pb Free Sn-2%Ag-x%Bi계 Solder의 특성에 관한 연구)

  • 흥순국;박일경;강정윤
    • Journal of Welding and Joining
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    • v.16 no.3
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    • pp.148-156
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    • 1998
  • The purpose of this study is to investigate the characteristics of Pb-Free Sn-2%Ag-Bi solder alloys. The solder alloys used in this study is Sn-2%Ag-(3,5,7,9%) Bi It is examined that their properties such as melting range, wettability, microstructure, microhardness, and tensile property. The addition of Bi(3,5,7,9%) lowered the melting point of the solder and the melting range was 196~203$^{\circ}C$. The wettability of the solder as equal to that of Sn-37% Pb solder. The morphology of structure did not change largely by addition of Bi. But the structure of cellular dendrite of linear type displayed. The tensile strength of the solder was superior to that of Sn-37%Pb solder. But the elongation was inferior to that of Sn-37%Pb solder. The hardness of Sn-2%Ag solder was tow times and that of Sn-2%Ag-Bi solder was three times of that in Sn-37%Pb solder. But the effect of increment of Bi content did not change largely.

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Effect of Composition Size of Sintered Body and Electrode on Resonant Characteristics of $Pb(Mn_{1/3}Nb_{2/3})O_3 PbTiO_3-PbZrO_3$ Piezoelectric Ceramics (소결체 및 전극의 크기와 조성이 $Pb(Mn_{1/3}Nb_{2/3})O_3 PbTiO_3-PbZrO_3$계 압전세라믹스의 공진특성에 미치는 영향)

  • 류영대;조상희
    • Journal of the Korean Ceramic Society
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    • v.23 no.1
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    • pp.60-66
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    • 1986
  • The effect of composition size of sintered body and electrode on resonant characteristics of the system $Pb(Mn_{1/3}Nb_{2/3})O_3 PbTiO_3-PbZrO_3$ has been decribed. Composition ranged from X=40 to X=55 diameter of sintered body ranged from D=6.5 to D=12.5(mm) and diameter of electrode ranged from De=5.5 to De=11 (mm) In the composition of morphotropic phase boundary antiresonant frequency (fa) dcreased slowly whereas resonant frequency (fr) decreased rapidly on the ground of this Δf(fa-fr) and electromechanical coupling fractor Kp increased and Qm showed low value. On the contrary in toward the composition of tetragonal and rhombo-hedral fa increased slowly whereas fr increased rapidly on the ground of this Δf and Kp decreased and Qm increased abruptly. Substance of the above statements have no concern with size of sintered body and ele-ctrode. The other side as the size of electrode decreased Qm fr, fa and Δf increased. Cm and Co dominantly affect the resonant frequency and antiresonant frequency.

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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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Removal Characteristics of Cd and Pb by Adsorption on Red Mud (Red mud를 이용한 중금속 Cd 및 Pb의 흡착제거 특성)

  • Yim, Soobin;Kim, Jaegon;Song, Hocheol
    • Journal of the Korean GEO-environmental Society
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    • v.12 no.7
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    • pp.39-47
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    • 2011
  • The objective of this study is to investigate the removal characteristics of cadmium(Cd) and lead(Pb) by adsorption on red mud and to study the adsorption characteristics of Cd and Pb using red mud activated by acid treatment and calcination. The adsorption of Cd and Pb on red mud was significantly achieved within 1hour and equilibrated after 5 hours. The adsorption capacity of Cd and Pb on red mud increased with increasing pH. The neutralization of red mud by distilled water or acid and the activation of red mud by acid treatment or calcination decreased the adsorption capacity of Cd and Pb on red mud, suggesting that Cd and Pb could be effectively eliminated by adsorption on red mud without any pretreatment or modification. Both Langmuir and Freundlich models were successfully applied to describe the adsorption behavior of Cd and Pb on red mud. The $q_m$ of Langmuir adsorption model and $K_F$ of Freundlich adsorption model were 5.230mg/g and 1.118mg/g for Cd and 22.222mg/g and 7.241mg/g for Pb, respectively.

Development of Hybrid (Sb/Ca) Flooded Lead-Acid Battery for Minimizing Water Loss (감액 특성 향상을 위한 하이브리드(Sb/Ca) 액식 연축전지 개발)

  • Song, Seung Yun;Lim, Tae Seop;Kim, Sung Jun;Jung, Yeon-Gil;Yang, SeungCheol
    • Korean Journal of Materials Research
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    • v.32 no.3
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    • pp.146-152
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    • 2022
  • One disadvantage of deep cycle flooded lead-acid batteries is increasing water loss caused by use of (+) Pb-Sb / (-) Pb-Sb alloy grid. Water loss is generated by the emission of hydrogen gas from the (-) electrode during battery charging. In this paper, we maintain cycle life aspect through the development of hybrid flooded lead-acid batteries to which a (+) Pb-Sb / (-) Pb-Ca grid is applied and deal with the improvement of water loss. The amount of water loss compared to that of the (-) Pb-Sb grid decreased when Ca was added to the (-) Pb grid. For the (-) Pb-Ca grid, it was confirmed that the time to reach 0.0 V, at which water decomposition occurs, was increased compared to that of the (-) Pb-Sb grid at the NPV (Negative Potential Voltage). In the cycle life test conducted with the BCI (Battery Council International) standard, compared to the (+) Pb-Ca grid, the (+) Pb-Sb grid increased the life cycle of the batteries and the (+) Pb-Ca grid showed an early end of life due to PbO corrosion layer generation, as determined through SEM / EDS and Tear Down analysis. In conclusion, by addition of Sb to (+) Pb grid and Ca to (-) Pb grid, we developed a hybrid flooded lead-acid battery that meets user requirements to improve water loss characteristics and preserve cycle life characteristics.

The Study of Characteristics of Consumer Purchasing Private Brand Products at Large-Scale Mart (국내 대형마트의 유통업체 브랜드 상품 구매 소비자의 특성 분석에 관한 연구)

  • Hwang, Seong-Huyk;Lee, Jung-Hee;Roh, Eun-Jung
    • Journal of Distribution Research
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    • v.15 no.4
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    • pp.1-19
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    • 2010
  • As having the movement of developing private brand (PB) goods, domestic big retailers are facing up with new problems. Thus, it is required studies of PB products, and how consumers recognize PB products as a consideration commodity set. Also, it is worthy in order that it gives us the important meaning on the marketing strategy with focusing on evaluating the differences between customers buying PB grocery goods with respect to demographic characteristics and purchasing behaviors. PB has some advantages for customers and retailers. However, according to AC Nielson's report (2005), Asian and emerging market has 1/5 sales relatively to Western countries. But we can assume that the emerging market has the most potential growth through this result. As a result from several other studies, it becomes necessary to not only increase the rate of selling composition of PB product temporarily, but also analyze the characteristics of customers using big retailers and segmenting customer groups to make PB product as a consideration commodity set for them. In addition, it is needed to have a variety of acts of marketing. From studies related to PB, there is a prejudice - cheap products have low quality - but, evaluation by customers who have used those products shows neutral stand, and there is a study representing that it is the most important to accumulate the belief between the retailers selling PB products and consumers using those for the accurate evaluation and intention on purchasing. Also, by the result from analyzing the characteristics of customers buying PB products, we could assume that higher income and higher education level, more preference on PB products. Especially, according to TNS's research, the primary targets of PB product are 30's who seeks value for money and planned spending habits, and 40's who have teenager children, and are interested in encouraging themselves. This paper used Probit model to analyze the characteristics of consumers. This model helps us to analyze with the variables representing the demographic characteristics of consumers (gender, age, educational level, occupation, income level, living area), and variables related to purchasing behavior (visiting frequency on big retailers, the average amount that they pay for goods in there, and check-up which brand made those goods). The method we used in this study is by man to man interview and survey on-line with the rate of 89% and 11% in Seoul and Gyunggi Province, respectively, for about one month from the beginning of February, 2008. As a result of this, under the assumption that people buy PB products more as long as they go shopping more, it was not meaningful for target groups which we pointed out as frequently visiting customers to be. Although, we have expected women buy more PB products than men do, gender doesn't mean anything for the result. And, it has inferred that married people buy more PB goods than singles do. It was also meaningless with variables related to occupation. Because housewives are often exposed to any kind of supermarket than workers are, we could not get any relatives. Moreover, we couldn't proof that younger generation prefer big retailers more than older people who 50~60's. Education levels doesn't affect on the purchase of PB product as well. Related to living area, the result is statistically not similar as we expected whether living in Seoul or not. It shows there is no relationship with the preference on retail brands and PB products, and it is similar with the study researched by TNS(2008) that customers tend to buy PB product impulsively no matter which brand it is and where they are even though their shopping place is the big market where customers are often using. Variables on which we had meaningful results are income level and living place. That is, customers who have 3,000,000~6,000,000 WON every month on average are more willing to buy PB products than other customers whose income is over 6,000,000 WON, and residents not living in Seoul prefer PB goods than those who are living in Seoul. To explain more about what we got, if there is only one condition about customer's visiting frequency on big retails, we could come up with this result that more exposed to PB products, more purchasing frequency. Consequently, it brings the important insight that large retailers have to prepare something to make customers visit them often to increase selling rate of PB products. To demonstrate the result of analyzing more, what is more efficient variables are demographically including marital status, income level, and residential area to buy items that affect the PB products and could include the frequency of visiting large markets by the purchase habits. Specifically, then, married couples rather than singles, middle-income customers than high-income customers, and local residents not living in Seoul than customers in Seoul are more likely to purchase PB goods. In addition, as long as a customer visits two times more, then the purchasing rate of PB products is to increase over 5.3%. Therefore, it seems that retailers are better to make a shopping place as fun and comfortable places. With overwhelming the idea that PB products are just cheap, one-time purchase goods, it is needed to increase the loyalty on those goods like NB products, try to make PB products as a consideration products set, and occur to sustainable sales. Especially, as suggested by this paper, it seems like it strongly needs to identify the characteristics of customers who prefer PB, to segment those customers, and to select the main target, and to do positioning with well-planned marketing strategies. Then, it is able to give us a meaningful point on marketing strategy by developing the field of PB study, identifying the difference of life style and shopping habits of customers.

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Effects of ZnS Insertion on the Characteristics of CaS:Pb Thin Film Phosphor

  • Park, Sang-Hee Ko;Kang, Seung-Youl;Kim, Kwang-Bok;Kim, Dong-Il;Yun, Sun-Jin
    • 한국정보디스플레이학회:학술대회논문집
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    • 2003.07a
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    • pp.1071-1074
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    • 2003
  • The effects of ZnS insertion on the characteristics of CaS:Pb phosphor were investigated. The intensity of photoluminescence of ZnS inserted CaS:Pb excited by 347nm were increased while that excited by 254nm was unchanged, compared to those of CaS:Pb thin film. The electroluminescent display having ZnS inserted CaS:Pb showed lower threshold voltage and higher efficiency than those of CaS:Pb ELD device.

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