• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.898-901
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• 2001

This study was carried out to research on the heavy metal contents of domestic and imported medicinal herbs. The heavy metals contents in 116 samples of 51 types of medicinal herbs were measured by using a modified Monier-Williams, mercury analyzer and inductively coupled plasma spectrometer(ICP). The heavy metal contents of medicinal herbs were as follows; Hg: 0.010(domestic: 0.010, imported: 0.010), Pb: 0.380(0.311, 0.449), Cd: 0.080(0.101, 0.059), As: 2.085(1.845, 2.324), Mn: 31.564(33.844, 29.283), Zn: 15.436(18.703, 12.168), Cu: 3.406(3.374, 3.437), Fe: 134.944(108.327, 161.561) by ppm unit. The measured values of Pb and Cd of domestic and imported medicinal herbs showed lower levels than the recommended levels of those in medicinal herbs by WHO/PHARM (Pb: not more than 10 ppm, Cd: not more than 0.3 ppm). Finally, this results will be used as a basic data for the future legislation on the regulation and control of heavy metal contents of medicinal herbs.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.03b
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• pp.528-535
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• 2000

Solid waste incinerator is expected to become widely used in Korea. The incineration of solid waste produces large quantities of bottom and fly ash, which has been disposed of primary by landfilling. However, as landfills become undesirable other disposal method are being sought. In this study, an experimental research is conducted to determine the geotechnical properties of municipal solid waste incinerator fly ash(MSWIF) in order to evaluate the feasibility of using the material for geotechnical applications. Basic pysicochemical characteristics, moisture-density relationship, strength, permeability, and leaching characteristics are examined. The results of MSWIF are compared to other MSWIF and coal fly ash which are used as construction material. In addition, the effectiveness of cement stabilization is investigated using various mix ratios. The result of stabilized mixes are compared to the unstabilized material. Cement stabilization is found to be very effective in reducing permeability, increasing strength, and immobilizing heavy metals. This results indicate that MSWIF with cement stabilization may be used effectively for geotechnical application.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.12 s.177
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• pp.163-169
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• 2005

Micro hole is ode of basic elements for micro device or micro parts. Micro electrochemical machining (ECM) can be applied to the machining of micro holes less than 50 ${\mu}m$ in diameter, which it is not easy to apply other techniques to. For the machining of passivating metals such as stainless steel, machining conditions should be chosen carefully to prevent a passive layer. The machining conditions also affect the machining resolution, In this paper, machining characteristics of micro ECM were investigated according to machining conditions such as electrolyte concentration and pulse conditions. From the investigation, optimal machining conditions were suggested for micro ECM of stainless steel.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.619-624
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• 2002

The purpose of this study is to manufacture sintered lightweight aggregate for non-structural concrete using sewage sludge, organic waste matter is produced to a sewage treatment plant. It is tested for basic property and strength of artificial aggregate according to addition ratio of sewage sludge, and the results are compared with imported aggregate from Spain. As the results of experiment, the manufactured lightweight aggregate could be used for non-structural concrete. Also, it was favorably comparable to those of the imported aggregate. When it is manufactured with aggregate, it is safe environmentally because of protecting elution of harmful heavy metals.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.648-651
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• 2004

Many damage models has been developed to express the degradation of materials. However, only minor damage model for concrete has been developed because of the heterogeneity of it unlike metals. To model the damaged behavior of concrete, this peculiarity as well as a load-induced anisotropic feature must be considered. In this paper, basic concepts of the thermodynamic theory is investigated to model the behavior of the damaged concrete in the phenomenological viewpoint. And the general constitutive relations and damage evolution equations are investigated too.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2003.05a
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• pp.146-147
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• 2003

The free-living nematode, Caenorhabditis elegans (C. elegans) has been adopted as a multicellular biosensor of biological toxicity for alkylphenol, organotin compounds and heavy metals. To adopt as a biosensor, suitability to assess must be fulfilledthrough several criteria; the organism must be sensitive to the testing toxicants, easy to manage in the laboratory and available throughout the year. C. elegans widely used as a simple multicellular organism in developmental biology studies and satisfies all these criteria, and its culture conditions, developmental staging, anatomy and genetic properties are well defined. In addition, researchers can take advantage of the worm's short life cycle, low cost and little individual variation. Moreover, genomic sequencing of C. elegans has recently been completed. With these aspectsof the organism, C. elegans become a more potent model organism for basic and applied bioassays.

• Journal of the Korean Ceramic Society
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• v.31 no.11
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• pp.1346-1354
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• 1994

In this study, the formation of magnetite using Fe(II) and Fe(III) hydroxides was investigated; The effects of hydroxide synthesizing pH and temperature, reaction temperature, and total water volume of hydroxide suspensions on the magnetite formation were studied. And the basic reaction behaviors of magnetite formation was discussed in the view of hydroxide formation reaction of Fe(II) and Fe(III) by titration. The characteristics of products were examined by TEM, VSM, XRD. From these experimental data, solid-solid reaction between Fe(II) and Fe(III) hydroxides is proposed as a new ferrite formation mechanism.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.296-300
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• 2001

In order to recycle the incineration ash (bottom ash and fly ash) generated from the incineration of municipal waste for a cement material, salts as well as heavy metal should be removed by the stabilization treatment. Most of these heavy metal and over 80% of salts are removed by a washing as a pre-treatment. However, wastewater which is another pollutant is generated by a washing, then proper treatment should be developed. First the characteristics of incineration ashes collected from two domestic full-sized incinerators were investigated and removal rate of salts and heavy metals from them also studied. The wastewater quality was compared to the criteria of the regulation by analyzing the characteristics of generated wastewater during the washing of incineration ash as a condition of liquid/solid ratio. Also, we tried to used this experimental results for the basic data to develop proper processing technique of municipal waste.

• Economic and Environmental Geology
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• v.30 no.2
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• pp.117-122
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• 1997

Soils collected from pusan metropolitan city were analysed for Cu, Pb, Zn, Cd, Mn to determine their dispersion patterns, mode of occurrences and to investigate the pollution level of heavy metals by urbanization. Element couples of Zn-Cu and Pb-Cd showed good correlation respectively and pollution sources of Zn-Cu, and Pb-Cd were similar. Pb was highly enhanced in dense traffic areas. Soil chemistry around mineralized areas originating from basic host rocks are characterized by high content of Pb, Zn, Cu, Cd, Mn and As.

• Journal of environmental and Sanitary engineering
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• v.19 no.2
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• pp.30-36
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• 2004

Dry decontamination technique is required for maintaining nuclear material handling equipment contaminated with highly radioactive material in a hot cell. In order to determine the optimum blasting conditions of dry ice pellet blasting device, the basic experiments have been conducted on the simulated test specimens of four types of metals. The removal efficiency of test piece was evaluated by the XRF analysis and the change of the surface condition before and after blasting. The removal efficiency of cesium on loose contamination was 100% under blasting pressure; 3 kg/$cm^2$, blasting distance; 10 cm, blasting time: 10 sec. In case of fixed contamination, the removal efficiency of cesium was almost 96% under blasting pressure; 4kg/$cm^2$, blasting distance; 10 cm, blasting time; 30 sec.