• Journal of the Korean GEO-environmental Society
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• v.2 no.3
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• pp.57-69
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• 2001

Sand pile is widely used as a ground improvement method. Although the primary purpose of constructing sand pile is accelerating consolidation, composite ground effect also can be gained by constructing sand pile. This study was accomplished to understand composite ground effect on the ground improved by sand piles which were applied as vertical drainage material when area replacement ratio was small relatively. For determining bearing capacities of origin ground and sand piles and analysing interaction between embankment and origin ground, bearing tests and earth pressure monitoring are performed. From the results, it turned out that the contribution of sand pile as a load bearing mechanism is not substantial. However, the bearing capacity of sand pile was increased to sixty percentages when compared with origin ground. The increasement of bearing capacity could be caused the change of consolidation characteristics during the process of consolidation by overburden load. Therefore, the composite ground effects depending on stiffness increasement of sand pile would be estimated as a factor decreasing consolidation settlement.

• Magazine of the Korea Concrete Institute
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• v.10 no.3
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• pp.135-142
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• 1998

본 연구는 초유동 콘크리트용 모르타르의 물/결합재비 및 고성능 감수제 첨가율에 따른 상대플로우 면적비와 상대깔대기 속도비의 상관관계를 실험으로 검토한 것이다. 구속수비 실험결과, C급 플라이애쉬>F급 플라이애쉬 > 석회석분순으로 나타났기 때문에 F급 플라이애쉬 및 석회석분은 유동성 개선에 효과적인 것으로 나타났다. 또한 모르타르 실험결과, 상대플로우 면적비와 상대깔대기 속도비는 고성능 감수제 첨가율이 일정할 경우 물/결합재비의 변화에 따라 원점을 지나는 직선관계로 나타났지만, 물/결합재비가 일정할 경우에는 고성능 감수제 첨가율의 변화에 따라 원점을 지나는 곡선관계로 나타났다. 따라서, 수식화 모델은 Rm= A. m0.4가 합리적이며, 최적값인 ( m .Rm)=(5.1)을 만족하는 배합조건은 플라이애쉬의 경우 치환율 30%, 물/결합재비 83%이며, 석회분의 경우 치환율30%, 물/결합재비 77%로 판명되었다.

• Journal of Chest Surgery
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• v.31 no.6
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• pp.586-590
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• 1998

Background: The regression of the left ventricular hypertrophy after prosthetic valve replacement in patients with aortic valvular stenosis is an important factor to determine the appropriateness of the replaced prosthetic valvular size. Methods: To assess the regression of myocardial hypertrophy, a retrospective analysis of Doppler echocardiographic and electrocardiographic data was undertaken before, soon after(7.5$\pm$2.1 day), and late after(10.7$\pm$1.8 months) surgery in 36 patients(22 males, 14 female, mean age 54$\pm$12.1 years, mean BSA 1.61$\pm$0.15m2) with predominant aortic valvular stenosis. The patients underwent St. Jude Medical aortic valve replacement. By the size of the valves used, the patients were divided into three groups(19, 21 and 23+). Results: The mean body surface area(1.48$\pm$0.13) in the patients with the 19 mm valve was smaller than that in the other groups(1.63$\pm$0.12)(p<0.05). No significant changes of ejection fraction were detected in all groups over time. Left ventricular muscle mass index(gm/m2) was reduced significantly in the 21 and 23+ groups over time(p<0.05), but there were no significant changes in the 19 mm valve group. The electric voltage height on EKG at the period of late after surgery was reduced significantly in all groups(p<0.05). Conclusion: Despite clinical improvement, the LVH was not reduced significantly in 19 mm valve group. Thus we suggest that more attention and additional procedures such as annular enlargement should be taken in patients who will undergo the replacement of 19 mm prosthetic valve.

• Proceedings of the Korean Society of Organic Agriculture Conference
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• 2005.12a
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• pp.55-64
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• 2005

1. 지렁이 분립량이 증가할수록 용적비중(bulk density), 유효수분함량(available water content), pH, 전기전도도(electrolytic conductivity), 무기물(ash), 전질소(total nitrogen), 양이온치환능력(cation exchange capcaity), 유효인산(available $P_{2}O_{5}$), 치환성양이온(exchangeable cation)이 증가하였다. 2. 근대는 분립 40${\sim}$100%의 혼합비율에서 초장(PL), 엽면적(LA), 엽수(NL), 엽면적(LA), 지상부 건물중(SHW), 근중(RW), 줄기두께(SD), 근중(RW) 및 생물학적수량(BY)이 다른 처리구보다 유의하게 높았다. 3. 열무는 분립 40${\sim}$60%의 혼합비율에서 초장(PL), 지상부 건물중(SHW), 근중(RW), 생물학적수량(BY)이 다른 처리구보다 유의하게 높았다. 3. 시금치와 상추는 40%의 혼합비율에서 지상부중(SHW), 근중(RW), 생물학적수량(BY)이 다른 처리구에 비해 유의하게 높았다(p${\leq}$0.05).

• Journal of Chest Surgery
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• v.34 no.1
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• pp.57-63
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• 2001

배경: 대동맥판막협착증 환자는 판막질환으로 인한 만성적인 후부하의 증가에 대한 보상성 좌심실 심근비후가 일어나게 된다. 대동맥 판막 치환 후 좌심실 심근 비후의 감소가 이루어지는 것으로 알려져 있으나 21mm이하의 작은 인공판막으로 치환시 좌심실 심근 변화에 대해 논란이 있다. 대상 및 방법: 1994년 9월부터 1998년 7월까지 한림대학교 강동성심병원 흉부외과에서 대동맥판막협착증으로 진단받고 판막치환술을 시행한 20명을 대상으로 하였다. 환자는 남녀 각각 13명, 7명이며 평균나이 61$\pm$13.8세 체표면적은 평균 1.57$\pm$0.14m$m^2$이었다. 환자의 추적관찰은 수술 전, 수술 후 초기(평균 10.4일) 및 수술 후 만기(평균 29.9개월)에 심초음파로 시행하였다. 환자들은 사용된 판막에 따라 2개의 군(1군;21mm 이하, 2군;23mm이상)으로 나누었다. 결과: 모든 군에서 NYHA Functional class의 유의한 감소가 있었다. 좌심실 구추률은 수술 전후 1군은 유의한 차이가 없었으나 2군에서는 유의한 차이가 있었다. 그러나 수술 전 좌심실 구출률이 2군에서 1군에 비해 유의하게 감소되어 있었다(p=0.044). 좌심실근량지수는 1군은 수술후 초기에 유의한 감소가 없었으나 수술후 만기에는 유의한 감소를 보여주었다. 그러나 2군은 수술후 초기와 만기에 모두 유의한 감소를 보여주었다. 결론: 21 mm이하 군과 23 mm이상 군 모두 임상적 호전이 있었다. 그러나 19 mm판막군이 2례로 적어 19 mm 판막의 사용시 환자의 나이와 체표면적, 운동량을 고려하여 신중한 판막선택이 고려된다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.5
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• pp.189-196
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• 2007

The purpose of this study was to analyze steel corrosion resistance of concrete containing copper slag. The specimens were made with normal portland cement and pozzolan materials with various replacement ratio and with W/B ratio ranging from 35% to 55%. Compressive strength, coefficient of chloride diffusion, corrosion area ratio and weight reduction ratio were determinated for the test. The results show that the concrete with pozzolan materials is superior resistant to chloride ions compared to the concrete without pozzolan materials. It was observed that blast furnace slag replacement ratio of 20% gives the best results with respect to chloride ion penetration and corrosion tests and observed that copper slag replacement ratio of 10% gives the seperior resistance compared to normal concrete.

• Journal of the Korean Electrochemical Society
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• v.14 no.3
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• pp.176-183
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• 2011

The electrochemical characteristics from various particle sizes of $Ce_{0.9}Gd_{0.1}O_{2-{\delta}}$ (CGO91) in composite cathode comprised of the samarium-strontium doped layered perovskite ($SmBa_{0.5}Sr_{0.5}Co_2O_{5+{\delta}}$) and CGO91 have been investigated for possible application as a cathode material for an intermediate temperature-operating solid oxide fuel cell (IT-SOFC). The area specific resistances (ASRs) of composite cathodes with CGO91 having smaller particle size ($0.4\sim42{\mu}m$) and SBSCO of 1 : 1 ratio (50wt% SBSCO and 50 wt% CGO91, SBSCO: 50) give the lowest ASR of $0.10{\mu}cm^2$ at $600^{\circ}C$ and $0.013{\Omega}cm^2$ at $700^{\circ}C$. However, composite cathodes with having relatively bigger CGO91 particle size show the two times higher ASR results than those of SBSCO : 50. From the 10 times thermal cycles in SBSCO : 50, the ASRs of SBSCO : 50 increased from $0.0193{\Omega}cm^2$ to $0.094{\Omega}cm^2$ at $700^{\circ}C$, however, the ASR value was maintained after 7 times of thermal cycling.

• Journal of the Korea Concrete Institute
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• v.18 no.6 s.96
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• pp.793-800
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• 2006

This paper reports test results to assess the influence of superplasticizers and different admixture on the flow and compressive strength development of cementless mortar using developed hwangtoh binder. Test specimens were classified into four groups: series for I the mixing ratio of superplasticizers, series II for a kind and replacement level of admixtures according to the variation of water/hwangtoh binder ratio, series III for the specific surface area and replacement level of ground granulated blast-furnace slag and series IV for the replacement level of powered superplasticizer agent developed to improve slump loss of concrete. The proper replacement level of each admixture is proposed for enhancement the flow and compressive strength of the hwangtoh binder mortar.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1C
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• pp.19-24
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• 2006

In this study, centrifugal model tests were performed to evaluate the stress sharing between SCP and surrounding clayey soil at composite ground improved by sand compaction pile with the low area replacement ratio. The SCPs were formed by the "frozen pile" method and pressure cells were installed on pile and surrounding clayey soil to observe stress sharing characteristics. As a result of centrifugal tests, it is shown that the value of stress concentration ratio is mainly affected by area replacement ratio, loading condition and elapsed time.

• Korean Journal of Soil Science and Fertilizer
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• v.31 no.3
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• pp.246-252
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• 1998

A survey was conducted to investigate the status of soils involving pH, electrical conductivity, total organic matter content, available phosphate and major exchangeable cations in the paddy soils sampled from 1,168 sites throughout the country. The content of soil chemical properties was lower on the average than the optimum levels for cropping. An average value showed pH 5.6, organic matter $25g\;kg^{-1}$, available phosphate $128mg\;kg^{-1}$, available silicate $72mg\;kg^{-1}$, and exchangeable potassium and the calcium and magnesium were 0.32, 4.0, $1.2cmol^+\;kg^{-1}$, respectively. Soil chemical properties was related with topography except soil pH. A soil pH and organic matter, available phosphate, exchangeable potassium increased with time while exchangeable calcium, magnesium available silicate decreased with time.