• Journal of Soil and Groundwater Environment
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• v.14 no.2
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• pp.17-25
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• 2009

The applicability of soil washing/flushing to treat a contaminated soil with cadmium (Cd) and copper (Cu) using a mixture of organic/inorganic extractant was evaluated in laboratory-scale batch and column tests. Citric acid was the effective extractant to remove Cd and Cu from the soil among various organic acids except EDTA. Carbonic acid was chosen as inorganic extractant which was not only low toxicity to environment, but also increasing soil permeability. Moreover, the optimum ratio of organic and inorganic extractant to remove Cd and Cu was 10 : 1, and this ratio of organic and inorganic extractant achieved removal efficiencies of Cd (46%) and Cu (39%), respectively. The increasing flow rate of extractant could explain the phenomena of soil packing when carbonic acid was used with organic extractant (i.e. EDTA and citric acid). Therefore, a mixture of organic extractant with inorganic extractant, especially carbonic acid, could resolve a problem of soil packing when this extractant was applied to a field application to remove Cd and Cu using in-situ soil flushing process.

• Journal of Wetlands Research
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• v.18 no.4
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• pp.378-385
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• 2016

This study aims to suggest the framework of functional assessment on lotic area based on HGM(Hydrogeomorphic) approach targeting Wetland Protected Areas which are in the type of river channel, and to set up the fundamental data as a reference wetland. A total of 10 factors in terms of hydrology, biogeochemistry, plant habitat and animal habitat was analyzed based on the original approach of HGM and each Functional Capacity Index(FCI) of those factors was calculated. As the result of the modified FCI analysis, Damyang riverine wetland which is with artificial river bank had high values in the variables of area ratio of actual vegetation in the foreland, the number of plant per area and the area ratio of Salix spp., and those values were highly reflected on the factors of Nutrient Cycling(947,668.00), Species Richness and Maintain Characteristic Plant Communites(6.39) and Maintain Spatial Structure of Habitat(11.00). The Hanbando wetland which is keeping the natural bank had higher values in the variables of structural scale and species diversity, and the those values were highly reflected on the factors of Energy Dissipation(17,805.16), Subsurface Storage of Water(0.54), Removal of Imported Elements and Compounds(103,052.73), Maintain Characteristic Detrital Biomass(2.31), Maintenance of Interspersion and Connectivity (6.50), Species Diversity of Benthic macro-invertebrates(1.60) and Species Diversity of Vertebrate & Species Number of Other Animals(2.52/ 151.50), compared to the Damyang Riverine Wetland.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.105-105
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• 2009

$ZrO_2$ is one of the most attractive high dielectric constant (high-k) materials. As integrated circuit device dimensions continue to be scaled down, high-k materials have been studied more to resolve the problems for replacing the EY31conventional $SiO_2$. $ZrO_2$ has many favorable properties as a high dielectric constant (k= 20~25), wide band gap (5~7 eV) as well as a close thermal expansion coefficient with Si that results in good thermal stability of the $ZrO_2/Si$ structure. In order to get fine-line patterns, plasma etching has been studied more in the fabrication of ultra large-scale integrated circuits. The relation between the etch characteristics of high-k dielectric materials and plasma properties is required to be studied more to match standard processing procedure with low damaged removal process. Due to the easy control of ion energy and flux, low ownership and simple structure of the inductively coupled plasma (ICP), we chose it for high-density plasma in our study. And the $BCl_3$ included in the gas due to the effective extraction of oxygen in the form of $BCl_xO_y$ compound In this study, the surface kinetic properties of $ZrO_2$ thin film was investigated in function of Ch addition to $BCl_3/Ar$ gas mixture ratio, RF power and DC-bias power based on substrate temperature. The figure 1 showed the etch rate of $ZrO_2$ thin film as function of gas mixing ratio of $Cl_2/BCl_3/Ar$ dependent on temperature. The chemical state of film was investigated using x-ray photoelectron spectroscopy (XPS). The characteristics of the plasma were estimated using optical emission spectroscopy (OES). Auger electron spectroscopy (AES) was used for elemental analysis of etched surface.

• Journal of Korean Foot and Ankle Society
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• v.11 no.2
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• pp.160-165
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• 2007

Purpose: Good results using minimal invasive hallux valgus surgery has been reported recently. We evaluate the usefulness of linear distal metatarsal osteotomy with minimal skin incision in mild and moderate hallux valgus deformity. Materials and Methods: Twenty-eight patients (thirty-one cases) who had mild to moderate hallux valgus deformity and underwent linear distal metatarsal osteotomy using minimal skin incision were evaluated between February 2005 and February 2006. Hallux-metatarsophalangeal-interphalangeal scale of AOFAS (American Orthopaedic Foot and Ankle Society) score was used as clinical evaluation. Preoperative, postoperative, after pin removal, and final follow up plain radiographs were used as radiologic evaluation. Results: Twenty-six cases (83%) among thirty-one cases showed more than average satisfaction, Average AOFAS score were improved from 63.2 points (range 45-74 points) to 86.4 points (range 67-93 points). Preoperative radiologic index of IMA $14.0^{\circ}$ (range $10-18^{\circ}$), HVA $30.2^{\circ}$ (range $19-39^{\circ}$), DMAA $13.8^{\circ}$ (range $5-23^{\circ}$) were improved postoperatively as IMA $8.3^{\circ}$ (range $5-10^{\circ}$), HVA $10.5^{\circ}$ (range $2-20^{\circ}$), DMAA $7.2^{\circ}$ (range $0-14^{\circ}$) correctively. Mean operative time was 15.5 minutes (range 11-18 minutes) and mean operative time was 5.6 days (range 2-8 days). Conclusion: Despite small skin incision and short operative time and admission period, linear distal metatarsal osteotomy with minimal skin incision showed similar results with conventional distal metatarsal osteotomy. Thus, it was thought to be useful operation in mild and moderate hallux valgus deformity.

• Applied Chemistry for Engineering
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• v.19 no.1
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• pp.80-85
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• 2008

Catalytic filter is capable of performing shallow bed dust filtration plus a catalytic reaction, promoted by a catalyst deposited in its inner structure. Such a feature may allow potential cost and space reduction in several environmental applications. Dust filtration and halogenated volatile organic compound (1,2-dichlorobenzene) destruction were carried out in a lab-scale reactor. $WO_3-V_2O_5/TiO_2$ supplied by MaGreen, which showed high catalytic acitivity at low temperature, was used as a catalyst. P-84 that can be operated under $250^{\circ}C$ was used as a felt. The catalytic activity and filtration efficiency of catalytic filters were investigated under the operating conditions, including temperature, face velocity, and dust concentration. The catalytic activity of catalytic filter increased with increasing temperature and the amount of catalyst loaded. The test results showed that the filtration efficiency was primarily affected by the face velocity. Pressure drop variations as a function of time were investigated for a variety of conditions. In case of virgin filter, a dramatic decrease in the pulse interval and a slightly increase in the base line pressure drop were observed. A relatively slow pressure drop build-up was recorded for the catalytic filter due to smooth and slippery surface characteristics of nanofiber. The catalytic filter indicated that high filtration efficiency over 99.98% and high catalytic activity over 90% at 1 m/min and $210^{\circ}C$.

• Korean Journal of Microbiology
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• v.34 no.3
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• pp.126-131
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• 1998

Reduction of hexavalent chromium to its trivalent form by leachate microorganisms was studied in batch and bench-scale continuous stirred tank reactor. The inoculum was a culture of microorganisms in leachate and capable of providing up to 90% chromate reduction during 72 h batch assay with $20mg\;Cr(VI)\;L^{-1}$ in minimal media containing different levels of leachate (10 to 60%) and glucose (50 to 200 mM). Addition of glucose increased the efficiency of chromate reduction, but adverse effect was observed with increase of leachate probably due to the competitive inhibition between chromate and sulfate ions. The continuous culture experiment was conducted for 124 days using synthetic feed containing different levels of chromate (5 to $65mg\;L^{-1}$) at room temperature. With a hydraulic retention time of 36 h, chromate reduction efficiency was mostly 100% when Cr(VI) concentrations in the reactor were in the range of 5 to $50mg\;L^{-1}$ Specific rate of Cr(VI) removal was calculated as $3.492mg\;g^{-1}\;protein\;h^{-1}$ during the period of 101~124 days from the start-up which showed 81.2% of average reduction efficiency. The results indicate the potential application of using leachate microorganisms for detoxification of hexavalent chromium in various chromium-contaminated wastewater from landfill or tannery sites.

• Journal of Environmental Science International
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• v.23 no.5
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• pp.771-780
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• 2014

Tetragonia tetragonides is a medicinal plant native to ocean sand soil of southern provinces and has significant effects on the prevention and curing of gastroenteric disorders. Despite of its popularity, supply of the plant has never met the level of demand because of the absence of an adequate culturing method. The present study, thereby, was conducted for classifying the plants with geographically different characteristics, studying growth habits, developing a new culturing method and establishing a large scale propagation system of selected superior individual plants. The study was also aimed for revealing optimum conditions for seed treatment, fertilization, and efficient culturing system and thereby, for utilizing the plant as a new income source for rural communities. The seed was elongated with size of 2.6 mm (width) ${\times}$ 1.8 mm (length). No difference in seed size was observed depending on different inhabitate. Each flower produced about 4.5~4.8 seeds. Germination rate was high for seeds matured for 40 days after fertilization, but deceased to 50% for seeds matured only for 20 or 30 days. Seed dormancy lasted 6 months and seed storage at humid $5^{\circ}C$ facilitated germination. Mechanical obstruct of seed germination was due to seed coat and removal of seed coat enhanced the germination rate. Optimum temp. for seed storage was $5^{\circ}C$, and high germination rate was maintained for 350 days. However, for stratification condition or at room temperature, germination was significantly reduced as storage time increased Optimum treatment of plant growth regulators was soaking in $GA_3$ 250 mg/L for 1 hr. The priming treatment with 50 mM $Ca(NO_3)_2$ at $20^{\circ}C$ for two days improved the seed germination with 10% compared to non-treated control. The treatment of 20% NaOCl for 3 hr. improved the seed germination rate up to 10% and 1 day ahead.

• Journal of Korean Orthopaedic Sports Medicine
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• v.9 no.1
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• pp.28-34
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• 2010

Purpose: The aim of this study was to evaluate short-term clinical results and second-look arthroscopic findings after double-bundle anterior cruciate ligament (DB ACL) reconstruction. Materials and Methods: Forty-nine patients, who were followed up for at least 24 months after DB ACL reconstruction, were included. Clinical results, such as, Lysholm knee and Tegner activity scores, and manual laxity and instrumented anterior laxity test results were evaluated. In fifteen patients (15 knees), second-look arthroscopy with staple removal was performed. At second-look arthroscopy, the authors assessed about reconstructed ACL rupture, subjective graft tension and extent of synovial coverage. Results: Lysholm knee scores significantly improved from 67.4 preoperatively to 96.1 at last follow-up (p<0.01). Tegner activity scale improved from 2.0 to 6.1. The Lachman test, at last follow-up, showed normal laxity in 39 (of 49) patients, and the pivot-shift test showed normal laxity in 36 (of 49) patients. Mean side-to-side differences improved significantly from 10.8 mm to 3.3 mm (p<0.01). Second-look arthroscopic findings showed that all patients had a normal or a near normal anteromedial bundle. However, 8 patients (53.3%) were found to have partial or complete posterolateral bundle rupture. Conclusion: Even though double-bundle ACL reconstruction was clinically effective means of restoring knee rotational and anteroposterior stabilities, there were some ruptured posterolateral bundles observed in cases under arthroscopy after double-bundle ACL reconstruction.

• Journal of The Korean Society of Agricultural Engineers
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• v.62 no.2
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• pp.17-29
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• 2020

The objective of this study was to find an optimum methane yield condition in anaerobic digestion of sewage sludge with microwave pretreatment. The pretreatment process was carried out using a lab scale industrial microwave unit (2,450 MHz frequency). The digestion efficiency of pretreated sludge was evaluated by biochemical methane potential (BMP) test. Box-Behnken design and Response Surface Analysis (RSA) were applied to determine the optimal combination of sludge mixing ratio (0 to 100%), power (400 to 1600 W), holding time (0 to 10 min) and pretreatment temperature (60 to 100℃). BMP test results showed that Volatile Solid (VS) removal efficiency was up to 48% at a condition of 0% for mixing ratio, 1600 W for power, 5 min for holding time, and 80℃ for pretreatment temperature. Methane production was up to 832.3 mL/g VS_removed at a condition of 50% for mixing ratio, 1000 W for power, 5 min for holding time, and 80℃ for pretreatment temperature. The results of the variance analysis (ANOVA) showed that the p-value of the power and pretreatment temperature among the independent variables were significant (p<0.05), and in particular, the pretreatment temperature significantly affected on the solubilization and methane production. The optimum condition for the maximum methane yield (847 mL/g VS_removed) was consist of 38.4% of mixing ratio, 909.1 W of power, 4.1 min of holding time, and 80℃ of temperature within the design boundaries.

• Applied Chemistry for Engineering
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• v.9 no.7
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• pp.1043-1046
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• 1998

Aluminium based inorganic flocculants are extensively used in this country in the removal of fine particles present in the raw water for the production of drinking water. These inorganic flocculants, however, have potential hazard of high residual aluminium ions in the treated waters, which is known to be one of the reasons of alzheimer's disease. Inorganic flocculants alone are sometimes incapable of treating water when there are excessive turbidity in the raw water sources due to flooding. A polyamine type polymeric flocculant has long been used to treat raw water in the drinking water production in the European countries and United State of America. The optimum reaction conditions such as mole ratio of epichlorohydrin(EPI) to dimethylamine(DMA), reaction temperature and time for each stage for the pilot scale preparation of polyamine from EPI-DMA was studied in this work. The variation of intrinsic viscosity and flocculating efficiency in the water treatment of the synthesized polyamines were evaluated. The residual materials after polymerization reaction were analyzed by gas chromatography to study the effect of variation of reaction conditions.