• Advances in environmental research
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• v.3 no.1
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• pp.71-86
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• 2014

Macronutrients ($Na^+$, $K^+$, $Ca^{2+}$, $Mg^{2+}$), yield and yield components, bioaccumulation and translocation of metal in plant parts of three Vigna species (V. cylindrica, V. mungo, V. radiata) were evaluated at 0, 50, 100 and $150mgkg^{-1}$ soil of Nickel (Ni). A marked inhibition (p < 0.001) in the distribution of various macronutrients was noticed in these Vigna species except for $Mg^{2+}$ content of the shoot and leaves. Similarly, all species retained more $Ca^{2+}$ in their roots (p < 0.05) as compared to the aerial tissues. Ni induced a drastic decline (p < 0.001) for various yield and yield attributes except for 100 seed weight. Toxicity and accumulation of Ni in plant tissues considerably increased in a concentration dependent manner. Vigna species signify an exclusion approach for Ni tolerance as both bioaccumulation factor (BF) and translocation factor (TF) were less than 1.0. The Ni content of plants being root > shoot > leaves > seeds. Scoring for percentage stimulation and inhibition (respective to control) at varying levels of Ni revealed tolerance of the species in an order of V. radiata > V. cylindrica > V. mungo. The acquisition of Ni tolerance in V. radiata seems to occur through an integrated mechanism of metal tolerance that includes sustainable macronutrients uptake, stronger roots due to greater deposition of $Ca^{2+}$in the roots, restricted transfer of Ni to above ground tissues and seeds as well as exclusion capacity of the roots to bind appreciable amount of metal to them. Thus, metal tolerant potential of V. radiata could be of great significance to remediate metal contaminated soil owing lesser impact of Ni on macro-nutrients, hence the yield.

• Nuclear Engineering and Technology
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• v.43 no.4
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• pp.391-398
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• 2011

The U metal chips generated in developing nuclear fuel and a gamma radioisotope shield have been stored under immersion of water in KAERI. When the water of the storing vessels vaporizes or drains due to unexpected leaking, the U metal chips are able to open to air. A new oxidation treatment process was raised for a long time safe storage with concepts of drying under vacuum, evaporating the containing water and organic material with elevating temperature, and oxidizing the uranium metal chips at an appropriate high temperature under conditions of controlling the feeding rate of oxygen gas. In order to optimize the oxidation process the uranium metal chips were completely dried at higher temperature than $300^{\circ}C$ and tested for oxidation at various temperatures, which are $300^{\circ}C$, $400^{\circ}C$, and $500^{\circ}C$. When the oxidation temperature was $400^{\circ}C$, the oxidized sample for 7 hours showed a temperature rise of $60^{\circ}C$ in the self-ignition test. But the oxidized sample for 14 hours revealed a slight temperature rise of $7^{\circ}C$ representing a stable behavior in the self-ignition test. When the temperature was $500^{\circ}C$, the shorter oxidation for 7 hours appeared to be enough because the self-ignition test represented no temperature rise. By using several chemical analyses such as carbon content determination, X-ray deflection (XRD), Infrared spectra (IR) and Thermal gravimetric analysis (TGA) on the oxidation treated samples, the results of self-ignition test of new oxidation treatment process for U metal chip were interpreted and supported.

• Advances in Traditional Medicine
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• v.7 no.2
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• pp.162-170
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• 2007

Woodfordia fruticosa Kurz. (Lythraceae), commonly known as Dhayero, is used in the treatment of various ailments in Nepal. In this study, the antioxidant capacity of crude extract and different polarity fractions of Woodfordia fruticosa flowers were assayed for their scavenging abilities against 1,1-diphenyl-2-picrylhydrazyl (DPPH) and nitric oxide radicals, competitive ${\beta}$-carotene bleaching, reducing power, metal chelating ability and total phenolic content. Crude extract and polar fractions showed stronger antioxidant capacity and contained very high level of total phenolics. They exhibited strong DPPH radical scavenging, nitric oxide scavenging and reducing power, medium ${\beta}$-carotene bleaching and poor metal chelating capacity. Positive correlation obtained between total phenolic content and antioxidant capacity assays, indicated the contribution of phenolics toards antioxidant capacity.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1999.10c
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• pp.651-656
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• 1999

This study was carried out to investigate the paddy soil and water quality in Boryung freshwater reservoir watershed during the non-cropping season. Soil pH of the Boryung freshwater reservoir watershed were 5.39∼5.78. Total-N and P contents were high by the accumulation of chemical fertilizer partly. Heavy metal content of paddy soils were natural background level. Water pH of the Boryung freshwater reservoir watershed ranged from 6.82 to 8.64. Total-N content affected by a livestock wastes and sewage water were the higher than that of others and total-P content showed below 0.1mg/L. Nitrate nitrogen contents was very high according to the influence a livestock waste and sewage water partly. Heavy metal contents of wateers were natural background level.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.8 no.2
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• pp.85-89
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• 1975

Heavy metal content have been determined in baby clams from March 1973 to April 1974 in Depori, Samchunpo, Korea. Monthly changes of mercury, lead, copper ana cadmium in the samples were irregular but as a whole, the content of mercury, lead, copper and cadmium were relatively high in summer season. The content of total mercury, lead, copper and cadmium in the samples ranged from 0.003 to 0.038 ppm, 0.096 to 0.931 ppm, 0.023 to 0.139 ppm and 0.009 to 0.038 ppm respectively. In the consideration of heavy metal content, it was concluded that baby clams in Depori, Samc hunpo, Korea is suitable for processing materials.

• The Korean Journal of Ecology
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• v.21 no.5_3
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• pp.695-702
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• 1998

This study was carried out to investigate to determine seasonal variation of dehydrogenase activity, phosphatase activity, adenosine tri-phosphate content and some physicochemical properties, such as soil pH, moisture content, organic matter and several heavy metal concentrations from Apr. 1997 to jan. 1998 in Pinus densiflora and Quercus mongolica forest in Mt. Nam, to explain a relationship between enzyme activity and the soil factors. There were ranges of 4.03-4.65 in soil pH, 18.65-51.09% in moisture content and 6.69-95.95% in orgainc matter. The organic matter content decreased with soil horizon, showing the higher values in Q. mongolica forest. In comparison to the results of Kawngneung site as control area, there were slightly differences due to a development level of forest ecosystem and microbial degradation of organic matter. The heavy metal concentrations showed 32.50-75.55 ${\mu}g/g$ in Cu, 69.33-134.84 ${\mu}g/g$ in Zn, 57.02-150.32 ${\mu}g/g$ in Pb, and 0.36-1.00 ${\mu}g/g$ in Mt. Nam. These values are higher than in Kwangneung site because of long-term exposure to air pollutants from central city. On the other hand, ATP contents in Mt. Nam were lower than in Kawngneung site in relation to soil organic matter, moisture content and relatively high heavy metal concentrations. ATP contents per soil weight was largest in F+H layer and in spring time of other seasons. Dehydrogenase activity as an index of soil microbial activity had a ranges of 170.67-1,221.66 ${\mu}g$ TPF/g that showed lower values than in Kawngneung site. However, phophatase activity had a contray tendency due to P fertilization for a continuous management. Those values increased through spring to a maximum in the summer and fall in autumn. This is basically caused by metabolic state of soil on the biological activity and several and several factors, such as aeration, soil temperature, vegetation and microflora.

• Journal of Powder Materials
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• v.10 no.6
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• pp.430-435
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• 2003

The phenomenon of electrical explosion of conductors is considered in the context of the changes in the energy and structural states of the metal at the stages of energy delivery and relaxation of the primary products of EEC. It is shown that these changes are related to the forced interaction of an intense energy flux with matter and to the subsequent spontaneous relaxation processes. The characteristics of nano-sized metal powders are also discussed. The preferential gas media during EEC is Ar+$H_2$. An increase in $e/e_s$ (in the range of values studied) leads to a reduction in the metal content. For reactive powders obtained with high metal content, it is necessary to separate the SFAP fractions, which settled on the negative electrode of the electric filter.

• Journal of Korean Society on Water Environment
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• v.23 no.2
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• pp.287-293
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• 2007

Heavy metal contamination and biological toxicity of mine drainages and sediments in abandoned mines were studied. Mine drainages had pH at a range of 2.94~7.86, and contained heavy metals at a toxic level. For coal mines, toxicity of mine drainage to Daphnia magna was attributable to acidic pH. In addition to the low pH, suspended heavy metals such as Zn and Cu contributed to toxicity of mine drainages at abandoned metalliferous mines. All mine sediments studied in this work showed biological toxicity to Chironomus riparius, having mortality at a range of 15~60%. However, its relationship with physicochemical properties including heavy metal content of the sediments was not statistically explained. Exceptionally clay ($< 2{\mu}m$ particle) content was negatively correlated with the biological toxicity for sediment samples collected at the same abandoned mines.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.12
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• pp.49-55
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• 2020

In order to improve the electromagnetic shielding rate of Carbon Fiber (CF), it was produced using the nickel nano-powder impregnating method. Using two types of nickel powder having thicknesses of 50 ㎛ and 100 ㎛, and a thermoplastic elastomer resin, a compound containing 10-20% nickel content was mixed and then manufactured through an extruder. The CF coated with the compound was woven and manufactured using a 1-ply specimen. The final nickel content of the specimen was verified using TGA and the distribution of nickel powder on the CF surface was verified using SEM. The metal shows a high shielding rate in the low-frequency band, but the shielding rate decreases at higher-frequency bands. The CF improves at the higher frequency band, and metals reflect electromagnetic waves while carbon absorbs electromagnetic waves. The study of shielding materials, which are stronger and lighter than metal, by using CF lighter than metal and enabling the shielding rate from low-frequency band to high-frequency band, confirmed that the larger the area coated with nickel nano-powder, the better the electromagnetic shielding performance. In particular, CF coated with a thickness of 100 ㎛ has a shielding rate similar to that of copper and can also be used for EV/HEV automotive cables and other applications in the future.

• Journal of Welding and Joining
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• v.17 no.5
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• pp.89-96
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• 1999

The base metal and weld metal of alloy designed austenitic stainless steels were electrochemically tested in artificial sea water. Pitting resistance of 14 different stainless steels was evaluated by measuring pitting potential. The effect of alloy element to pitting potential was evaluated by changing chromium, nickel, sulfur content. The site of pitting initiation was observed by optical microscope. As a result of electrochemical test, pitting resistance of weld metal was higher than base metal, and rapidly cooled weld metal has higher pitting potential than slowly cooled weld metal. In case of primary δ-ferrite solidification, pitting potential was increased, but residual δ-ferrite was detrimental to pitting resistance. Chromium was more effective to pitting resistance than nickel, and sulfur was very detrimental element to pitting resistance.