• Analytical Science and Technology
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• v.9 no.4
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• pp.406-410
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• 1996

The adsorption behaviors of transition metal ions on the poly(N,N'-bispalmitoyl-1, 12-diaza-3, 4;9,10-dibenzo-5,8-cyclopentadecane) has been determined by adsorption process in aqueous solution. The order of concentration factor(CF) and the amount of adsorption were Cu(II)

• KSTLE International Journal
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• v.9 no.1_2
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• pp.22-25
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• 2008

This paper investigated the wetting and adhesion property of undulated DLC film with surface morphology controlled for a reduced real area of contact. The undulated DLC Films were prepared by 13.56 MHZ radio frequency plasma enhanced chemical vapor deposition (r.f. PECVD) by using nanoscale Cu dots surface on a Si (100) substrate. FE-SEM, AFM analysis showed that the after repeated deposition and plasma induced damage with Ar ions, the surface was nanoscale undulated. This phenomenon changed the surface morphology of DLC surface. Raman spectra of film with changed morphology revealed that the plasma induced damage with Ar ions significantly suppressed the graphitization of DLC structure. Also, it was observed that while the untreated flat DLC surfaces had wetting angle starting ranged from $72^{\circ}$ and adhesion force of 333ni. Had wetting angle the undulated DLC surfaces, which resemble the surface morphology of a cylindrical shape, increased up to $104^{\circ}$ and adhesion force decreased down to 11 nN. The measurements agree with Hertz and JKR models. The surface undulation was affected mainly by several factors: the surface morphology affinity to cylindrical shape, reduction of the real area of contact and air pockets trapped in cylindrical asperities of the surface.

• Journal of the korean society of oceanography
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• v.32 no.3
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• pp.112-119
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• 1997

Coastal sediments collected near the Youngkwang Nuclear Power Plant were analysed for major(Al$_2$O$^_3$, Fe$^_2$O$^_3$, MgO, CaO, Na$^_2$O, K$^_2$O, TiO$^_2$, MnO), trace (Ba, Sr, V, Co, Cr, Cu, Ni, Zn, Pb) metal, and P$^_2$O$^_5$ contents. The composition of bulk metals from most stations fits within the range as those in the average crustal and sedimentary rocks, suggesting that the anthropogenic perturbation of these components is insignificant. The abundance and distribution of total contents for the majority of metals in the surface sediment could be explained by the grain size and were associated with mud (<63 ${\mu}$m) contents. However, distributions of Ca, K, Sr and Ba did not have any significant association with the sediment grain size. This may be due to the geochemical coherence among these metals in certain minerals abundant in coarse grained fractions. The distribution of Pb appears to be partly affected by the contribution from aerosol fallout. Using the R'-mode factor analysis, we show that the variance of the metal contents could be explained by four factors which account for 93.7% of the total variance. It appears that texturally controlled and/or sorting factors influenced by fine fraction are the most dominant factors which determine the relative abundance and distribution of metals in the study area.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.657-658
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• 2006

Although there are many numerical models to simulate fs laser ablation of metals, no model can analyze the ablation phenomena over a wide range of fluence. In this work, a numerical code for simulating the fs laser ablation phenomena of metals has been developed. The two temperature model is employed to predict the ablation rate and the crater shape of metals using phase explosion mechanism in the relatively high fluence regime. Also, the ultrashort thermoelastic model is used for the low fluence regime to account for spallation of the sample by high strain rate. It has been demonstrated that the thermoelastic stress generated within the sample can exceed the yield stress of the material even near the threshold fluence. Numerical computation results are compared with the experiment for Cu and Ni and show good agreement. Discussions are made on the hydrodynamic model considering phase change and hydrodynamic flow.

• Journal of the Korean Society for Heat Treatment
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• v.1 no.1
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• pp.13-23
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• 1988

The hardenability of alloyed ductile cast irons was studied for 54 different alloy compositions obtained from eight commercial and laboratory foundries. The alloying elements investigated for their effects on hardenability were Si(2.0 to 3.0%), Mn(0.0 to 0.8%), Mo(0.0 to 0.6%), Cu(0.0 to 1.5%), and Ni(0.0 to 1.5%). Two hardenability criteria, a first-pearlite hardenability criterion and a half-hard hardenability criterion, were used to determine hardenability of ductile irons. Prediction models for each hardenability criterion were developed by multiple regression analysis and were well agreed with previous experimental results. Molybdenum was the most potent hardenability promoting element followed by manganese, copper and nickel ; silicon had little effect on hardenability and reduced the hardenability as silicon content increased. When alloying elements were presented in combination, strong synergistic effects on the hardenability were observed especially between molybdenum, copper and nickel. The hardenability of ductile iron was strongly influenced by austenitizing temperature. Increasing austenitizing temperature up to $955^{\circ}C$, hardenability increased gradually but decreasing rate and then decreased as temperature increased above $955^{\circ}C$. Unless reducing segregation by very long-time annealing treatment, the hardenability of ductile iron was not significantly influenced by segregation of alloying elements.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.149-155
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• 2003

Objectives of this research were to fractionate heavy metals in soil samples in the upper Okdong River basin and to assess the potential pollution index of each metal fraction. Soil samples were collected from cultivated land soils and analyzed for physical and chemical properties. pH of cultivated soils ranged from 5.2 to 7.6. Contents of total kelhaldal nitrogen and loss on ignition were in the ranges of 0.6∼2.5%, and 1.9∼12.9%, respectively. Heavy metals in the cultivated land soils were higher in the abandoned closed coal mine near field soils than those in the paddy soils. Total concentrations of metals in the cultivated land soils were in the orders of Zn > Pb > Ni > Cu > Cd, exceed the corrective action level of the Soil Environment Conservation Law and higher than the naturals were abundance levels reported from uncontaminated cultivated land soils. Mobile fractions of metals were relatively small compared to the total concentrations. Soil Pollution Assesment Index(SPAI) values of each fraction of metals were leveled from Non polluted to Moderately polluted based on total concentrations. SPAI values of mobil fractions were lower than those of immobile fractions. Results on metal fractions and SPAI values of the cultivated land soils indicate that field soils samples were contaminated with heavy metals and had potential to cause a detrimental effects on plants. A prompt countermeasure to prevent field soils in the abandoned closed coal mine near fields are urgently needed.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.04a
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• pp.186-190
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• 2005

본 연구는 울산 석유화학공단 지역을 중심으로 여천공단과 용연공단의 불포화 토양층에서 지표면하 1.0m 지점까지 3구간 $(GL-0{\sim}0.2m,\;0.2{\sim}0.5m,\;0.5{\sim}1.0m)$으로 나누어 토양을 채취하여 토양환경보전법에서 규제하는 중금속 성분을 실내분석 하였다. 연구지역의 토양내 pH는 모든 구간에서 평균 $6.9{\sim}7.0$으로 나타났으며, 대체적으로 $7.5{\sim}8.5$ 사이의 약알칼리성을 가지며 공장이 밀집한 지역에서는 pH $4.1{\sim}4.5$ 정도의 강한 산성을 나타내었다. 연구지역의 토양내 중금속은 Cd, CU, Pb, As, Hg, Ni, $Cr^{+6}$ 및 Zn 성분이 분석되었다. Zn와 $Cr^{+6}$ 성분을 제외하고는 시료채취 구간별 함량의 차이는 거의 나타나지 않았다. $Cr^{+6}$과 Zn 성분은 $0{\sim}0.2m$ 구간에서 높은 함량을 나타내었다.

• Transactions of Materials Processing
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• v.18 no.6
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• pp.500-507
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• 2009

Tensile deformation behavior with different strain rate was investigated. $Zr_{56.2}Ti_{13.8}Nb_{5.0}Cu_{6.9}Ni_{5.6}Be_{12.5}$(bulk metallic glass alloy possessed crystal phase which was called $\beta$-phase of dendrite shape, mean size of $20{\sim}30{\mu}m$ and occupied 25% of the total volume) was used in this study. Maximum tensile strength was obtained as 1.74GPa at strain rate $10^2s^{-1}$ and minimum strength was found to be 1.6GPa at $10^{-1}s^{-1}$. And then, maximum plastic deformation occurred at the strain rate of $5{\times}10^{-2}s^{-1}$ and represented 1.75%, though minimum plastic deformation showed 0%. In the specific range of strain rate, relatively higher plastic deformation and lower ultimate tensile strength were found with lots of shear bands. The fractographical observation after tensile test indicated that vein like pattern on the fracture surface was well developed especially in the above range of strain rate.

• Journal of Soil and Groundwater Environment
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• v.15 no.3
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• pp.1-6
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• 2010

This study investigated the change of metal contamination levels according to amendment of enforcement regulation of the Soil Environmental Conservation Act in Korea. As an analytical result of 87 samples in abandoned metallic mine area, the extracted amount of As, Pb and Cu with aqua regia was 4.3~29.6 times higher than that with hydrochloric acid extraction and the number of samples, which contamination levels were found to exceed soil contamination standards, was also increased. On the other hand, in case of Cd, Zn, and Ni, the number of samples, which contamination levels were found to exceed soil contamination standards, was decreased or similar. These results can be used as a preliminary material in comparison between the soil pollution data accumulated previously and the data obtained by the revised standard method for the examination of soil pollution.

• Journal of Soil and Groundwater Environment
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• v.20 no.4
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• pp.8-14
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• 2015

Plants grown in metal-contaminated sites have to be managed and disposed of safely even in phytoremediation because heavy metals can be transferred to other organisms through the food chain, which could result in bioaccumulation in organisms of a higher trophic level. However, if the harvested plants could be used for bioenergy, the ecological risk is reduced and phytoremediation improves economic feasibility. This study researched the effects of EDDS (Ethylenediamine disuccinate) on the heavy metal uptake performance of Brassica campetris and Sorghum biocolor, both of which have potential as bioenergy plants. The results showed that EDDS could increase Pb, Cu, Ni, Cd, and Zn concentrations in the roots and shoots of both of these plants. Furthermore, EDDS reduced the metal inhibition of the S. bicolor length growth. The translocation factors (TF) of S. bicolor and B. campestris are smaller than one for all five heavy metals tested and decreased by the following order: heavy metal + EDDS > heavy metals only > uncontaminated soil. The results suggest that with regard to plant growth and metal accumulation, S. bicolor treated with EDDS is more suitable than is B. campestris for the phytoremediation of soils contaminated with multiple metal species.