• Journal of Life Science
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• v.10 no.6
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• pp.558-563
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• 2000

Effect of inhibitors on Vibrio parahaemolyticus cell growth and its urease activity was studied. The growth of the bacterium and the enzyme activity were inhibited by the addition of 0.02% p-hydroxymercuric benzoate, $HgCl_2$and $AgNO_3$. However, same concentration of boric acid, thallium acetate and $Pb(NO_3)_2$ did not affect the cell growth but inhibited urease activity by 25%, 29%, and 38%, respectively. Acetohydroxamic acid was the most potent inhibitor on cell growth by inhibiting 40% but did not affect urease activity. To investigate the effect of inhibitors on urease activity, urease was purified and confirmed on SDS-PAGE. The purified urease was inhibited 100% by the addition of 1 mM acetohydroxamic acid and $AgNO_3$but no inhibition was occurred by the addition of the same concentration of thallium acetate. and the addition of 0.01 mM of $HgCl_2$ and acetohydroxamic acid inhibited the purified urease activity by 39% and 24%, respectively. On 0.1 millimolar basic, acetohydroxamic acid and $HgCl_2$inhibited 4 times more active in urease inhibition than p-hydroxymercuric benzoate whereas no inhibition was occurred either thallium acetate or $Pb(NO_3)_2$.

• Korean Journal of Environmental Biology
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• v.18 no.2
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• pp.269-277
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• 2000

When Persicaria thunbergii and Rumex crispus were treated with Cd($NO_3$)$_2$ and Pb($NO_3$)$_2$ of 5 or 10 mM for 5 days, the amount of bioaccumulation of $Pb^{2+}$ in the leaf of P. thunbergii was 2.87-8.08$\mu\textrm{g}$/g and that of $Cd^{2+}$ was 0.82-2.79$\mu\textrm{g}$/g. In the case of P. thunbergii, the concentration of $Pb^{2+}$ in the leaf was higher than that of $Cd^{2+}$. On the other hand, in R. crispus, the concentration of $Cd^{2+}$ and $Pb^{2+}$ were similar as follows ; 1.49$\mu\textrm{g}$/g in $Cd^{2+}$ 5mM, 2.90$\mu\textrm{g}$/g in Cd2+ 10mM, 1.83$\mu\textrm{g}$/g in $Pb^{2+}$ 5mM and 2.73$\mu\textrm{g}$/g in $Pb^{2+}$ 10mM. The remaining rate of heavy metals and the variation of pH in the cultured soil decreased as compared with control (100 % and pH 6.48) after 5 days as follows; to 77.l% and pH 6.39 in $Cd^{2+}$ 5mM, 90.2% and pH 5.79 in $Cd^{2+}$ 10 mM, 81.1% and pH 6.00 in $Pb^{2+}$ 5mM, and 85.7% and pH 5.80 in $Pb^{2+}$ 10 mM. The result of size exclusion chromatography, several phytochelatins were seperated from the extract of the leaf of both plants treated with heavy metals. The molecular mass of these phytochelatins were estimated as follows; in the case of P. thunbergii, about 4,300-8,600 da by $Cd^{2+}$ and about 3,200-9,700 da by $Pb^{2+}$, and in R. crispus, about 4,300 da by $Cd^{2+}$ and about 3,200-7,500 da by $Pb^{2+}$. In addition, $A_{254}$ of these phytochelatins were higher than $A_{280}$. [Phytochelatin, Persicaria thunbergii, Rumex crispus]

• Progress in Superconductivity and Cryogenics
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• v.21 no.4
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• pp.1-5
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• 2019

We investigated the effect of Fe₃O₄ addition on the critical temperature of (Bi, Pb)-2223 polycrystalline samples. Bi_1.6Pb_0.4Sr₂Ca₂Cu₃O_10+δ + x wt. % Fe₃O₄ (x = 0.0, 0.2, 0.4, 0.6, and 0.8) samples were prepared by using a solid-state reaction method. The analysis of X-ray diffraction data indicates that as Fe₃O₄ is added, dominant phase of the sample changes from Bi-2223 to Bi-2212 with an increasing Bi-2201 phase. The transition temperature of the samples drastically decreased with the Fe₃O₄ addition. The resistance data of samples with x = 0.2 and 0.4 showed a double transition indicating a coexistence of Bi-2223 and Bi-2212 phase while the samples with x = 0.6 and 0.8 showed a single transition with a semiconducting behavior. This phase transition may originate from changes in local structure of the Bi-2223 system by Fe₃O₄ addition. Analysis of the pair distribution function of the Cu-O pair in the CuO₂ plane calculated from extended X-ray absorption fine structure data revealed that the oxygen coordination of copper ion changes from CuO₄ planar type (x = 0.0 - 0.4) to CuO₅ pyramidal type (x = 0.6, 0.8). The correlated Debye-Waller factor, providing information on the atomic disorder within the CuO₂ plane, shows an inverse relation to the coordination number. These results indicate that addition of Fe₃O₄ changes the oxygen distribution around Cu in the CuO₂ plane, causing a phase transition from Bi-2223 to more stable Bi-2212/Bi-2201 phases.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.3
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• pp.1-8
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• 2002

In order to study electric properties of (Pb$\_$0.9/La$\_$0.1/)Ti$\_$0.975/O$_3$(PLT (10)) films with varying excess lead concentration (7.5, 10, 12.5, 15 ㏖% excess lead), the PLT films were deposited by sol-gel process. DTA analyses reveal that the crystallization temperature of the precursor powers decreased with increasing amount of excess lead. XRD patterns of PLT reveal pure perovskite structure and the preferred orientation increased with increasing Pb content in the films. With increasing amount of excess P$\_$b/, the relative permittivity ($\xi$$\_$r/) increased and leakage current density at 100 ㎸/cm transformed 4.01$\times$10$\^$-5/, 2.42$\times$10$\^$-6/, 1.27$\times$10$\^$-6/, 1.56$\times$10$\^$-6/A/㎠ respectively. In the results of hysteresis loops measured at 166 kV/cm, the remanent polarization (P$\_$r/) and the coercive field (E$\_$c) are 6.36$\mu$C/cm and 58.7 ㎸/cm, respectively (at 12.5 ㏖% excess P$\_$b/) With increasing amount of excess Pb, the remanent polarization for PLT thin film degraded to about 44%, 27%, 15%, 16% of the initial value after 10$\^$9/ cycles./TEX>) With increasing amount of excess Pb, the remanent polarization for PLT thin film degraded to about 44%, 27%, 15%, 16% of the initial value after $10^{9}$ cycles.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.5
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• pp.467-471
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• 2015

Thus far, solders used in electronics remain lead-based. Pb-free solutions in electronic components and systems are receiving increased attention in the semiconductor and electronics industries. Pb-free materials currently in used are Sn-37Pb, Sn-4Ag and Sn-4Ag-0.5Cu/Ni plate joints. In this study, solder alloys were used at high temperatures for artificial aging processing that was performed at $150^{\circ}C$ for 0hr, 100hr, 200hr, 400hr, 600hr and 1000hr. The SP test was conducted at $30^{\circ}C$ and $50^{\circ}C$. As a result, the maximum shear strength of all the specimens decreased with the increase in artificial aging time and temperature of the SP test. In addition, Pb-free solders showed higher total fracture energy compared with Sn-37Pb at high temperatures. The mechanical properties of Sn-4Ag-0.5Cu solder/Ni plate joints remained in excellent conditions in electronic parking systems at high temperatures.

• Journal of Agricultural Extension & Community Development
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• v.21 no.1
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• pp.83-115
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• 2014

The current study aimed to explore the levels of consumers' perception for the PB apples which mainly sold in the large retailers, and then suggest the efficient marketing strategies for activating sales of the PB apples among the farm produce. The findings of the study revealed that the levels of the consumers' perception of value for the PB apples were influential on the brand credibility. In addition, the levels of the quality, perception of value, and brand credibility significantly affected the purchase intention. The image of the brand, however, did not show the effects on the brand credibility and purchase intention. Based on the study, in order to activate the brand for the local farm produce, the analysis results could suggest the four alternatives. Firstly, it is needed for the NB apples to be standardized and improved in terms of the qualities. Secondly, the more efficient ways to facilitate the purchases for the NB apples should be reconsidered in the emotional package. Thirdly, the levels of customers' perceptions for NB apples need to increase by providing them with convenient ways of purchases. Lastly, connecting consumers' groups with producers' groups could eventually enhance the brand credibility.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.161-164
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• 2001

In this paper, we investigated the dielectric and piezoelectric properties of Pb(Sb, Nb)O$_3$-Pb(Zr, Ti)O$_3$ ceramic(PSN) for piezoelectric transformer and actuator etc. Effect of MnO$_2$ addition on the PSN ceramic was investigated. Anisotropic properties of electromechanical coupling factor and piezoelectric properties proved to be varied with amount of MnO$_2$ impurity and sintering temperature. The electromechanical coupling factor k$_{p}$ of 0.38 and the mechanical quality factor Q$_{m}$ of 1944 were obtained from the specimen with 0.4 wt% MnO$_2$ sintered at 115$0^{\circ}C$ addition. Experimental results indicated that the PSN ceramic with MnO$_2$ impurity can be effectively used for piezoelectric transformer and actuator.tor.

• Journal of the Korean Applied Science and Technology
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• v.27 no.2
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• pp.196-201
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• 2010

The influence of red lead($Pb_3O_4$) to curing and formation reaction properties when it was added in positive material of lead acid battery for vehicle use has been investigated. At the results, it was confirmed that the addition of red lead led 4BS crystal size to be smaller and increased the rates of 4BS formation and Pb consumption. Consequently the curing time was shortened to half compared with that of red lead-free one. In addition to this, the lead acid battery prepared by adding red lead showed 14% higher efficiency at the life cycle test than that without red lead.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.2
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• pp.352-354
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• 2010

The effects of Au addition on the structure and the superconducting properties of Bi system bulk have been investigated. Au exists in the metalic form in above materials. It does not affect the formation and structure of the BiSrCaCuO(2223) phase. The superconducting transition temperature Tc does not change for $Bi_{1.7}Pb_{0.3}Sr_2Ca_2Cu_3O$ composite However Au doping can make the grains smaller. Metallic Au can make gathers on the grains boundary and lead to the increment of critical transport current density. The current density of $Bi_{1.7}Pb_{0.3}Sr_2Ca_2Cu_3Au_{0.5}O$ was 1000A/$cm^2$ at liquid nitrogen temperature.

• Journal of the Korean institute of surface engineering
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• v.15 no.4
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• pp.192-207
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• 1982

A study has been made of the interaction parameters of Zn other elements in dilute solutesd solution of molten cadmium alloys over the temperature range of 450 to 570$^{\circ}C$. The experi-mental measurementss were made in a touch instant cell using a fusedd Licl-KCl electrolyte. The activity of zinc in binary and ternary solutions sexhibiteds a strong positive deviation from Raoult's law. The addition of silver, indium or lead increased the activity of zinc whereas addition of copper, bismuth or tin decreased the zinc activity slightly. The results for all the metallic solutions showed a linear dependence of reciprocal of ab-solute temperature over the experimental range. The interaction parameters obtained are as follows.