• Journal of Korean Society of Environmental Engineers
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• v.32 no.2
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• pp.185-192
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• 2010

The objective of this study was to investigate the effectiveness of stabilization for army firing range soil highly contaminated with Pb (total Pb: 29,000 mg/kg) using calcined waste oyster shells. The calcination was conducted to activate quicklime from calcite. In order to evaluate the effectiveness of calcination, both natural oyster shells (NOS) and calcined oyster shells (COS) were applied to the Pb contaminated soil. Stabilization was conducted by mixing the contaminated soil with oyster shell media at 5-20 wt% and cured for 28 days. Following 28 days of curing, Pb leachability was measured based on the Korean Standard Test method (0.1 N HCl extraction). The treatment results showed that the COS treatment outperformed the NOS treatment. All of the NOS treatments failed to meet the Korean warning standard of 100 mg/kg. However, the Pb concentrations were significantly reduced to 47 mg/kg and 3 mg/kg upon 15 wt% and 20 wt% COS treatments, respectively which passed the Korean warning standard. Moreover, -#20 mesh materials were more effective than the -#10 mesh materials in effectively reducing Pb leachability. The scanning electron microscopy (SEM)-energy dispersive X-ray spectroscopy (EDX) results indicated that Pb immobilization was strongly linked to Al and Si.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.1063-1070
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• 2011

In this study, total of 5 different chemical amendments were evaluated for determining kinetic parameters and stabilization efficiency of heavy metals in aqueous phase. Standard solution of Cd and Pb ($100mg\;L^{-1}$) was mixed with various ratio of amendments (1, 3, 5, 10%) and heavy metal stabilization efficiency was monitored for 24hrs. All examined amendments showed over 90% of removal efficiency for both Cd and Pb except zerovalent iron (ZVI) for Cd (43-63%). Based on result of heavy metal stabilization efficiency, it was ordered as $CaCO_3$ > Dolomite > Zeolite > Steel slag > ZVI for both Cd and Pb in aqueous phase. For kinetic study, first order kinetic model was adapted to calculate kinetic parameters. In terms of reaction rate constants (k), zeolite showed the fastest reaction rate (k value from 0.4882 for 1% to 2.0105 for 10%) for Cd and ZVI (k value from 0.2304 for 1% to 0.5575 for 10%) for Pb. Considering reaction rate constant and half life for heavy metal stabilization, it was ordered as Zeolite > $CaCO_3$ > Dolomite > Steel slag > ZVI for Cd and $CaCO_3$ > Dolomite > Steel slag > Zeolite > ZVI for Pb. Overall result in this study can be interpreted that lime containing materials are more beneficial to remove heavy metals with high efficiency and less time consuming than absorbent materials.

• Polymer(Korea)
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• v.25 no.4
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• pp.575-586
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• 2001

Stabilized polyacrylonitrile (PAN) fibers can be transformed into quasi-carbon fibers with different properties depending on heat-treatment processing parameters at lower temperatures than temperature for the fabrication of carbon fibers. It has been investigated from the preliminary work that appropriate quasi-carbonization processes at about 1100$^{\circ}C$ strongly influence various properties of quasi-carbon fiber/polymer composite as well as quasi-carbon fiber itself. The objective of the present work is to prepare quasi-carbon fibers from stabilized PAN fibers using various quasi-carbonization cycles and to examine their properties. Two temperature regions, up to 800$^{\circ}C$ and above 1000$^{\circ}C$, were used for quasi-carbonization processes. The chemical composition, physical properties, thermal stability, microstructure, mechanical properties and electrical resistivity of the quasi-carbon fibers prepared with different final heat-treatment temperatures, heating rates, holding times, heating steps, and purging gas purity were extensively examined. The results were also compared with those from stabilized PAN fiber and commercial PAN-based carbon fiber. The present study showed that a variety of properties of quasi-carbon fibers significantly depended on several quasi-carbonization process parameters.

• Journal of the Korea Organic Resources Recycling Association
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• v.3 no.1
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• pp.3-11
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• 1995

This study was conducted to estimate the stabilization degree of compost which made from Korean food wastes. To make the compost, food wastes were mixed with dried paper sludge, sawdust and the rotten wood waste which had cultivated mushrooms, and then mixture was composted in $1.1m^3$ of chamber which installed with the blower for maintaining the aerobic condition. Y value, EC and pH were changed remarkably for the early stage of composting. These changes showed that the compost of food wastes could be stabilized within 30~35 days and that the substrate, food wastes, can be easily used as energy source for microorganisms. Although these phyico-chemical properties indicated that food wastes could be composted within 30 days during the composting, the temperature of pile maintained over $50^{\circ}C$ for 80 days, and C/N ratio decreased gradually for over 50 days. In conclusion, more than 50 days were required to stabilize the compost of food wastes.

• Korean Security Journal
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• no.25
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• pp.89-107
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• 2010

The purpose of this study was to evaluate the effects of using cervical spinal stabilization exercise for the improvement of pain intensity, cervical range of motion, neck disability index, reposition sense, muscle tenderness with chronic neck pain in private security. For 21 patients diagnosed with chronic cervical pain and divided into cervical spinal stabilization exercise group and postural correction exercise group. Each exercise was conducted for 8 weeks. Pain and neck disability index were measured before and after exercise using the visual analogue scale(VAS) and the neck disability index(NDI). Range of motion were measured electronic goniometer, muscle tenderness of upper trapezius ad sternocleidomatoid were measured algometer, reposition sense were measured reposition panel before and after exercise. After 8 weeks of exercise, the cervical stabilization exercise group pain and neck disability were significantly decreased(p<0.05). Also there was significant difference in both group(p<0.05). In addition, range of motion, muscle tenderness reduce rate, reposition sense were significantly increase as compared to the pre-post exercise in cervical stabilization exercise group(p<0.05). But there was no significantly difference in postural correction group before and after exercise(p>0.05). And there was significantly increase more cervical stabilization exercise group than postural correction exercise group in range of motion, muscle tenderness reduce, reposition sense. In summary, cervical spinal stabilization exercise is more effective in improving cervical range of motion, muscle pain, reposition sense in private security on chronic cervical pain patients, in reducing patients' pain and disability. It is an effective treatment to aid rehabilitation in these cases.

• Korean Security Journal
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• no.20
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• pp.71-93
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• 2009

The purpose of this study was to evaluate the effects of using spinal stabilization exercise for the improvement of atrophy of the multifidus and psoas major, of pain and disability with chronic low back pain in private guard and security. For 42 patients diagnosed with CLBP, and divided into spinal stabilization exercise group(SSEG) and general spinal strengthening exercise group(GSSEG). Each exercise was conducted for 10 weeks. Pain and disability were measured before and after exercise using the Visual analogue scale(VAS) and the Oswestry disability index(ODI). Cross section area(CSA) of both the left and right multifidus and the psoas major at the upper end plate of L4 were measured before and after exercise using computed tomography(CT). After 10 weeks of exercise, the both group's pain and lumbar disability were significantly decreased(p<0.01). Also there was significant difference in both group(p<0.05). In addition, the CSA of the left and right multifidus and posas major were significantly increased as compared to the pre-exercise in both group(p<0.01). But SSEG's cross sectional areas of multifidus was more significantly increase than GSSEG(p<0.05). In summary, Spinal stabilization exercise is more effective in improving atrophy in private guard and security patients, in reducing patients' pain and disability. It is an effective treatment to aid rehabilitation in these cases.

• Journal of the Korean GEO-environmental Society
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• v.25 no.5
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• pp.5-13
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• 2024

This paper investigates the stabilization feasibility of contaminated sediment contaminated with benzyl butyl phthalate (BBP) using acid/base-modified activated carbon. The efficiency of stabilizers was evaluated by analyzing the impact of the activated carbon on the decomposition and adsorption of the contaminant, along with the biological effects on earthworms. Additionally, the contaminant migration was monitored with the BBP concentration in pore water using low-density polyethylene. The research results indicated that the accumulated concentration of BBP was approximately 2% lower in the experimental group applying a 5% mixture ratio of modified activated carbon compared to the group applying a 10% mixture ratio. The leaching into water was reduced by over 18% in all experimental conditions after 7-day exposure period. Over 25% reduction was observed after 28-day exposure. The pore water concentrations were measured. After 7 days of exposure, the mechanically mixed experimental group exhibited a higher pore water stabilization rate compared to the biologically mixed group. Within the mechanically mixed group, the experimental group with 10% mixture of modified activated carbon showed a 1% higher stabilization rate than the group with 5% mixture. After 28 days of exposure, the biologically mixed experimental group demonstrated a higher pore water stabilization rate compared to the mechanically mixed group. Moreover, within the biologically mixed group, the experimental group with 10% mixture of modified activated carbon showed approximately 0.1% higher stabilization rate than the group with 5% mixture.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.1420-1424
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• 2006

제주도는 연 평균 강우량이 전국 평균의 1.5배에 해당하는 다우지역이다. 그러나 화산섬으로서의 특수한 지형 및 지질구조 때문에 지표수가 거의 발달하지 않았으며, 이러한 수문지질여건으로 인하여 수자원의 대부분을 지하수 개발에 의존할 수 밖에 없어 용수 수요량의 증가를 충족시키기 위한 지하수 개발이 가속화되어 왔다. 그러나 지하수의 과다개발 등으로 지하수의 부존량은 점차 감소할 수 밖에 없는 실정이며, 제주도의 투수성이 높은 지질과 토양으로 지하수 오염에 취약해 최근 수질기준을 초과하는 지역이 늘어나고 있는 실정이다. 이에 제주 당국은 국제자유도시특별법 규정에 권장대상 빗물이용시설에 대한 시설비 보조에 관한 사항 등을 정하여 우수이용을 권장하고 있다. 본 연구에서는 제주도지역의 강우패턴과 세대별 생활용수량 자료를 조사 분석하여 효율적인 가정용 우수 이용 시스템으로서 갈수기에도 안정적으로 용수를 공급받을 수 있는 저류탱크의 크기 및 우수배관의 관경결정 기법을 개발하고 수질의 안정화를 위한 우수수질 안정화 기법을 제시하였다. 우수이용 시스템의 설계를 위하여 개발한 모형인 DDP, DOS 모형을 이용하여 강우 및 용수의 기초자료가 비교적 풍부한 제주도 지역에 적용함으로써 국내의 다른 산간지역과 도서지역에서도 본 시스템의 적용이 용이하게 될 수 있을 것으로 판단되며, 본 시스템 및 시스템 모형화에 대한 지속적인 연구를 통하여 보다 경제적이고 안정적인 시스템 설계가 가능한 범용적인 모형의 개발을 할 수 있을 것으로 사료된다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2011.11a
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• pp.166-169
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• 2011

항만간 허브항 경쟁이 극심해 지고 있는 오늘날, 컨테이너 선사는 M&A 및 전략적 제휴로 컨테이너터미널 운영사와의 가격 협상력의 우월적 지위를 갖게 되어 컨테이너터미널 운영사간 선사 및 화물유치를 경쟁을 더욱 부추기고 있다. 그러나 수요측면에서 컨테이너물동량 증가율 둔화로 컨테이너터미널에서 처리해야 할 물동량은 한정되어 있는 반면, 공급 측면에서 항만터미널의 지속적인 건설은 항만간 또는 터미널간 물량 유치경쟁을 과열시키고 있다. 특히 부산항은 신항 개장이후 북항과 신항간 물동량 유치경쟁으로 인하여 항만하역시장의 교란을 가져오고 있다. 본 연구에서는 부산항 컨테이너 항만하역시장의 구조적 특성분석과 설문조사 방법론을 통하여 향후 부산항 항만하역시장의 안정화 방안을 제시하고자 한다. 시장구조 분석결과 부산항은 한정된 처리물량과 신항의 개장으로 인한 공급과잉, 그리고 정부의 지역항만개발정책에 따른 컨테이너화물의 분산처리로 지속적인 부산항의 비중 감소로 선석당 처리물량이 감소하고 있다. 이에 따라 선사의 우월적 지위를 이용한 하역료 인하요구로 터미널운영사간에 서비스경쟁이 아닌 비협력적인 가격경쟁으로 재정수지가 악화되고 있고, 또한 '10년 외국적선사의 처리물량이 60%를 차지하고 있어 국부유출이 심각한 실정이다. 따라서 하역시장 안정화 방안으로 항만시설 수요 및 공급의 불균형을 조정하기 위하여 항만풀링공동기금관리를 통한 재정수지를 확보할 수 있는 항만풀링제도를 제안하며, 이 제도의 운영을 위하여 한시적으로 컨테이너터미널 운영사별 처리물량 상한제를 도입하는 것이 바람직하다고 판단된다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.7 no.3
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• pp.377-383
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• 1997

Yttria-stabilized TZP alloyed with pentavalent oxides $(Ta_2O_5,\;Nb_2O_5)$ were fabricated by the conventional sintering method at $1500^{\circ}C$ in air to construct the simplified ternary phase diagram. The phase stability of tetragonal -$ZrO_2$ from the quasi-binary system $ZrO_2-YTa(Nb)O_4$, which do not transform to monoclinic-$ZrO_2$ even for a wide range of grain size and annealing temperature, was investigated to determine composition region of the non-transformable $t-ZrO_2$ solid solution$(NT_{ss})$. Phase stability of $NT_{ss}$ was probably due to the enhanced stability of $_YTa(Nb)O4$ having the tetragonal fergusonite structure. It was experimentally found that mixtures having $NT_{ss}$ alloyed with $T_{ss}$ by weight%% showed both excellent phase stability of $t-ZrO_2$ and fracture toughness even though the calculated composition of the mixture /was located outside $NT_{ss}$ composition region.