• Korean Journal of Environmental Agriculture
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• v.24 no.4
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• pp.379-385
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• 2005

This study was conducted to find out a useful bioremediation technology for heavy metal contaminated soil and water. We isolated strain CPB from heavy metal contaminated soil and evaluated the tolerance level and adsorption capacity of strain CPB to heavy metals (Strain is not determined yet). Strain CPB showed variable tolerance limit to different kinds heavy metal or concentrations of heavy metals. The growth of strain CPB was significantly inhibited by mixed heavy metals (Cd+Cu+Pb+Zn) than that of by single heavy metal. Strain CPB showed high binding capacity with Pb (Pb>Cd>Cu>Zn). In general, strain CPB showed high uptake of heavy metals such as Pb, Cd and Cu. It was observed that the capacity of heavy metal uptake from mixture of heavy metals was reduced in comparison with single heavy metal treatment. But total contents of heavy metal bound with cell in mixed heavy metal showed higher than in single heavy metal treatment. Heavy metal adsorption in cells was affected by several external factors, such as temperature and pH etc.. The optimum temperature and pH of the adsorption of heavy metal into cells were ca. $25{\sim}35^{\circ}C$ and pH ca. $5{\sim}7$, respectively. A large number of the electron dense particles were found mainly on the cell wall and cell membrane fractions, which was determined by transmission electron microscope. Energy dispersive X-ray spectroscopy revealed that the electron dense particles were the heavy metal complexes the substances binding with heavy metals.

• Design & Manufacturing
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• v.15 no.2
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• pp.42-48
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• 2021

In this paper, when manufacturing large/multi-mold parts (more than 30 core parts),A mold manufacturing (tolerance) management system was established through design-processing linkage.The mold manufacturing (tolerance) management system is a design-based measurement shape/measurement position determination system, M/C processing-linked measurement drive system,It is composed of four parts: CAD-linked measurement result analysis system and manager mold part quality management system.In addition, the constructed system was applied to the field and the effect of system construction was evaluated by comparing it with the existing process.As a result of the evaluation, the measurement precision is within 0.02mm, and the time it takes to measure after the end of processing is shorter than that of the existing process.(12 hours → 2 hours) It was shortened to 16.7%.In addition, it was confirmed that the time required for reprocessing after measurement was reduced by 25% (4 hours → 1 hour) compared to the existing process.

• Korean Journal of Plant Tissue Culture
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• v.27 no.4
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• pp.325-337
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• 2000

All living organisms depend on soil and water for their sustained growth and development. In recent years, sustenance of life in these growth matrices has been adversely affected by the cumulative increase in environmental pollutants resulting from increasing population, growing economies and resource-use. This review provides a glimpse into the problem of global environmental pollution, the traditional technologies available for remediation and the scope of emerging‘plant-based remediation’technologies. Phytoremediation, the use of plants to effectively remove or stabilize contaminants from the growth substrate, is a low cost and ecologically friendly alternative to the common‘dig and dump’technologies. The field of phytoremediation has been driven by the intrinsic need for identification of ideal candidate plant species. To date, there are only a very few identified plants which satisfy all of the prerequisites for use in phytoremediation. The review focuses on one such plant species, the common horticultural plant scented geranium (Pelargonium sp.), with demonstrated potential to remediate metal / salt contaminated soils / aqueous systems. The characterization of tolerance and metal / salt accumulation potential of Pelargonium sp. and its efficacy in remediating complex contaminated sites are described. The unique ability of scented geraniums to tolerate excessive amounts of multi-metals, hydrocarbon and salt mixtures, and at the same time to accumulate significant amounts of metal and salt ions in the biomass, renders this plant species as one of the ideal candidates for remediation.

• Transactions of Materials Processing
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• v.20 no.2
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• pp.104-109
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• 2011

The metal front case of a mobile phone is manufactured by press forming and welding of thin metal sheets. Twisting of the frame after the forming process is one of main obstacle for the assembly with reinforcement by welding. This study introduces a method preventing twisting of the metal front case frame in press forming. The spring-back after forming produces twisting of the frame, which leads to a low structural stiffness. To reduce twisting, connectors are required to reinforce the structural stiffness of the frame. In this study, the twisting profile is evaluated using a finite element(FE) analysis for various connector shapes. The actual connector shape is determined by minimization of the frame twisting within the tolerance of the FE-analysis. To verify the validity of the proposed blank shape, a forming experiment is performed and the twisting profile is measured using a 3D laser scanning method. The dimensional accuracy is found to be within the tolerance and in good agreement with the FE-analysis.

• Journal of Life Science
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• v.19 no.12
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• pp.1685-1689
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• 2009

Phytochelatins (PCs) are small polypeptides synthesized by PC synthase (PCS). They are present in various living organisms including plants, fission yeast, and some animals. The presumed function of PCs is the sequestration of cytosolic toxic heavy metals like cadmium (Cd) into the vacuoles via vacuolar membrane localized heavy metal tolerance factor 1 (HMT-1). HMT-1 was first identified in fission yeast (SpHMT-1), and later in Caenorhabdtis (CeHMT-1). Recently, its homolog has also been found in PC-deficient Drosophila (DmHMT-1), and this homolog has been shown to be involved in Cd detoxification, as confirmed by the heterologous expression of DmHMT-1 in fission yeast. Therefore, the dependence of HMT-1 on PC in Cd detoxification should be re-evaluated. I heterologously expressed SpHMT-1 in cytosolic PC-deficient yeast, Saccharomycea cerevisiae, to understand the dependence of HMT-1 on PC. Yeast cells expressing SpHMT-1 showed increased tolerance to Cd compared with control cells. This result indicates that SpHMT-1 is not strictly correlated with PC production on its function. Moreover, yeast cells expressing SpHMT-1 showed increased tolerance to exogenously applied glutathione (GSH) compared with control cells, and the tolerance to Cd was further increased by exogenously applied GSH, while tolerance in control cells was not. These results indicate that the function of SpHMT-1 in Cd detoxification does not depend on PCs only, and suggest that SpHMT-1 may sequester cytosolic GSH-Cd complexes into the vacuole.

• Journal of the Microelectronics and Packaging Society
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• v.7 no.1
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• pp.13-18
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• 2000

Low temperature co-fired ceramics on metal (LTCC-M) is efficient for embedding passive components with good tolerance in a module due to the dimensional stability in x and y directions by the constraint of metal core during the firing. In addition, the radiation noise can be reduced by metal core. In this paper, embedded passive components were introduced and a power amplifier module (PAM) fabricated by using the passive components was explained. The embedded passive components in test patters showed the tolerance of 10~20% and the good repeatability in tolerance of embedded passives was maintained in module fabrication. The shortened traces in multi chip modules (MCMs) make the signal delay time decreased and the embedded passives simplify the packaging processes owing to the less solder points, which enhance the electrical performance and increase the reliability of the modules. The LTCC-M technology is one of the promising candidates for RF application and is expected to expand its applications to power and high performance devices.

• The Korean Journal of Ecology
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• v.18 no.1
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• pp.147-156
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• 1995

Restoration of ecosystems degraded by heavy metal pollution can be accomplished by soil amendment and selection and utilization of plants tolerant to heavy metals. Two former zinc mine sites, Sambo Mine in Hwasung, Kyonggi-do and the Second Yonhwa Mine in Samchuk, Kangwon-do, were selected for collection of plant samples and for determination of heavy metal tolerant species. Dominant species on mine waste deposits in Hwasung site were Panicum bisulcatum and Echinoch/oa crus-galli, while those in Samchuk site were Aster yomena, Setaria viridis, Artemisia lavandulaefolia and Oenothera odorata. Mean contents of zinc, lead and cadmium in Hwasung soil were 103, 117 and 1 ppm, respectively, while those in Samchuk soil were 23, 6 and 4 ppm, respectively, Zinc contents were higher in Echinochloa crus-galli from Hwasung and in Artemisia lavandulaefolia from Samchuk, while lead contents were higher in Panicum bisulcatum and Echinochloa crus-galli from Hwasung and Lactuca sonchiJolia and Pinus densiJolia from Samchuk. Plant species with higher cadmium contents were Panicum bisulcatum and Lactuca sonchiJolia. Comparison of metal contents between roots and shoots showed that Echinochloa crus-galli was a zinc accumulator, while Panicum bisulcatum, Persicaria hydroPiPer, Pinus densiJlora and Lactuca sonchiJolia were zinc excluders. In addition, Panicum bisulcatum and Persicaria hydroPiPer were proved to be lead excluders. When both heavy metal contents in plant tissues and biomass of individual plants are considered, it can be concluded that Echinochloa crus-galli and Panicum bisulcatum from Hwasung and Artemisia lavandulaefolia and Aster yomena are heavy metal absorbing plants. The effect of heavy metals on seed germination showed that Artemisia princeps var. orientalis had higher germination rates, but no significant difference in concomitant decrease of germination rates among the species investigated were found by increasing heavy metal contents.

• Journal of Applied Biological Chemistry
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• v.60 no.2
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• pp.113-117
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• 2017

Bioremediation is a technique using microorganisms to clean up contaminated pollutants including heavy metals. It is well known that yeasts have a high capacity to remove a wide range of metals by biosorption. Therefore, this study was focused on to obtain yeast mutant that has strong tolerance to zinc (Zn), one of representative heavy metals. The Zn resistant yeast mutant (ZnR) was induced and isolated by growing yeast cells in media containing 1 mM $ZnCl_2$ and gradually increasing the concentration until 80 mM $ZnCl_2$, in which cells were adapted and survived. The induced ZnR cells showed strong tolerance to Zn stress compared with control cells. Moreover, the ZnR cells showed increased tolerance to cadmium and nickel stress but decreased tolerance to copper stress. The increased tolerance of ZnR cells to Zn stress was due to mutation of genes. This study can be useful in bioremediation of heavy metals as the metal tolerant microorganism was artificially induced in short time.

• Journal of the Korean Electrochemical Society
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• v.10 no.4
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• pp.279-282
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• 2007

When reformer for fuel cell is used, CO in hydrogen gas leads to a seriously decreased membrane electrode assembly (MEA) performance by catalyst poisoning. The effect of CO on performance of modified MEA by sputtering method is studied in this paper. The experimental results show that sputtered Pt and Ru thin film improve a single cell performance of MEA and sputtered metal thin film has a CO tolerance. The air injection process on anode show improved CO tolerance test result. Moreover, Pt, Ru and PtRu thin film by sputtering had influence on the CO tolerance with air injection process.

• Journal of Plant Biotechnology
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• v.47 no.4
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• pp.324-329
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• 2020

Reed (Phragmites spp.) is a rhizomatous plant of the Poaceae family and is known as high tolerant plant to heavy metal contaminants. This plant is widely recognized as a Cd root-accumulator, but improved heavy metal tolerance and uptake capacity are still required for phytoremediation efficiency. To enhance capacity of hyperaccumulator plants, ethyl methane sulfonate (EMS) as chemical mutagen has been introduced and applied to remediation approaches. This study aimed to select EMS-mutagenized reeds representing high Cd resistance and large biomass and to investigate their ability of Cd accumulation. After 6 months cultivation of M₂ mutant reeds under Cd stress conditions (up to 1,500 µM), we discovered seven mutant individuals that showed good performances like survivorship, vitality, and high accumulation of Cd, particularly in their roots. Compared to wild type (WT) reeds as control, on average, dry weight of mutant type (MT) reeds was larger by 2 and 1.5 times in roots and shoots, respectively. In addition, these mutant plants accumulated 6 times more Cd, mostly in the roots. In particular, MT8 reeds showed the greatest ability to accumulate Cd. These results suggest that EMS mutagenesis could generate hyperaccumulator plants with enhanced Cd tolerance and biomass, thereby contributing to improvement of phytoremediation efficiency in Cd-contaminated soil or wastewater. Further studies should focus on identifying Cd tolerance mechanisms of such EMS-mutagenized plants, developing techniques for its biomass production, and investigating the practical potential of the EMS mutants for phytoremediation.