• 한국지반환경공학회 논문집
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• 제15권4호
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• pp.5-11
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• 2014

최근 도심지의 구조물 건설 시 다양한 라이프라인이 공간의 효율적인 활용 측면에서 지중에 매설되고 있으며, 이러한 라이프라인의 신설 및 유지보수 등을 위해 굴착이나 뒤채움 작업이 빈번하게 이루어지고 있다. 라이프라인 매설 시 지반을 굴착하며, 매설 후 채움재 모래를 사용하여 되메움을 하는 것이 일반적이다. 이러한 경우 통신관, 가스관, 상하수도 등의 관하부와 측면 좁은 공간의 뒤채움은 다짐작업이 어려우며, 다짐작업 시 토사의 특성상 추가적으로 침하가 발생한다. 이러한 문제점을 해결하기 위한 방법으로 미국 및 일본 등과 같은 선진국에서 건설 발생토를 재활용하여 잔토처리 비용을 줄이고, 충분한 유동성을 확보한 유동성 채움재가 사용되고 있다. 또한 지중 매설관 건설 외에도 기초 하부 지반의 보강에도 유동성 채움재를 활용할 수 있을 것으로 판단되며, 특히 기계 기초 하부 지지층이 연약한 경우, 유동성 채움재를 적용하여 빠른 시간 안에 지반을 개량하는 목적에 적합할 것으로 판단된다. 특히 기계 기초 하부 지지층의 경우, 단순한 기계 하중에 의한 정적 지지력 산정뿐만 아니라 기계의 진동에 의한 동적 하중이 가해지므로 기초 하부 지지층의 동적거동특성이 평가되어야 한다. 따라서 본 연구에서는 유동성 채움재를 기계 기초 지지층으로 활용하는데 있어서의 적용성을 판별하기 위해 국내에서 일반적으로 볼 수 있는 점토와 황토를 현장발생토로 가정하여 세립분 함량을 달리한 유동성 채움재의 강도 및 동적 거동특성을 파악하였다. 또한 현장 발생토를 대신하여 산업 폐기물인 매립석탄회를 활용하여 유동성 채움재를 조성하여 그 성능을 비교하였다. 그 결과, 매립석탄회를 혼합하여 사용한 경우, 일반적인 건설발생토를 사용한 경우보다 높은 7일 재령 강도와 전단탄성계수를 보였다.

• 한국지반환경공학회 논문집
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• 제13권12호
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• pp.59-66
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• 2012

본 연구에서는 철도정비창 부지 내에 폐기물 및 중금속오염 구간에서 채취한 토양을 대상으로 하였다. 그리고 효율적인 정화공정 설계를 위하여 고농도 오염구간, 저농도 오염구간, 폐주물사 함유 시료를 대상으로 입도분포 및 입도 분포 오염농도 분석을 실시하였다. 하지만 폐콘크리트, 폐목재 등의 건설폐기물, 폐주물사, 소각재 등이 부지 전반에 걸쳐 매립되어 있어 일반토양 오염과 다른 양상을 보이고 있었다. 따라서 일반적인 중금속정화기술로는 오염원이 감소하지 않아 혼합된 폐기물 중에 자성을 띠는 성분을 자력선별을 적용하여 실험한 결과 중금속 오염도는 감소하는 것으로 나타났다.

• 콘크리트학회논문집
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• 제17권2호
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• pp.303-309
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• 2005

This study aims the evaluation of the corrosion of steel bar embedded in antiwashout underwater concrete, which has rather been neglected to date. To that goal, accelerated steel bar corrosion tests have been performed on three series of steel bar-reinforced antiwashout underwater concrete specimens manufactured with different admixtures. The three series of antiwashout underwater concrete were: concrete constituted exclusively with ordinary portland cement (OPC), concrete composed of ordinary portland cement mixed with fly-ash in $20\%$ ratio (FA20), and concrete with ground granulated blast furnace slag mixed in $50\%$ ratio (BFS50). The environment of manufacture was in artificial seawater. Measurement results using half-cell potential surveyor showed that, among all the specimens, steel bar in OPC was the first one that exceeded the threshold value proposed by ASTM C 876 with a potential value below -350mv after 14 cycles. And, the corresponding corrosion current density and concentration of water soluble chloride were measured as $30{\mu}A/mm^2$ and $0.258\%$. On the other hand, for the other specimens that are FA20 and BFS50, potential values below -350mV were observed later at 18 and 20 cycles, respectively. Results confirmed the hypothesis that mineral admixtures may be more effective on delay the development of steel bar corrosion in antiwashout underwater concrete.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.759-764
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• 2004

In this study, the experiment was carried out to investigate and analyze the ready-mixed concrete production of ultra-high strength concrete with mixing strength of $100N/mm^2$ according to types of mineral admixtures. The main experimental variables were water/binder ratio $25.0\%$, water content $160kg/m^3$ and mineral admixtures such as fly ash, silica fume and meta kaolin. According to the test results, the principle conclusions are summarized as follows. 1) even if it secures similar slump, the viscosity appear to difference by mixing condition relatively. 2) The autogeneous shrinkage of ultra-high strength concrete is profitable that use admixture, and heat of hydration is desirable that apply considering countermeasure enough in the advance. 3) The concrete that use SF10+MK10 on 56days could confirm that it is possible that achieve compressive strength more than $100N/mm^2$ under mixing conditions that is appearing by compressive strength $102.7N/mm^2$.

• Journal of Forest and Environmental Science
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• 제37권4호
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• pp.269-279
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• 2021

This study was carried out to introduce the forest cover types of the Baekdudaegan inhabiting the number of native tree species. In order to understand the vegetation distribution characteristics of the Baekdudaegan, a vegetation survey was conducted on the major 20 mountains of the Baekdudaegan. The vegetation data were collected from 3,959 sample points by the point-centered quarter method. Each mountain was classified into 4-7 forests by using various multivariate statistical methods such as cluster analysis, indicator species analysis, multiple discriminant analysis, and species composition analysis. The forests were classified mainly according to the relative abundance of Quercus mongolica. There was a total of 111 classified forests and these forests were integrated into the following nine forest cover types using the percentage similarity index and by clustering according to vegetation type: 1) Mongolian oak, 2) Mongolian oak and other deciduous, 3) Oaks (Mixed Quercus spp.), 4) Korean red pine, 5) Korean red pine and oaks, 6) ash, 7) mixed mesophytic, 8) subalpine zone coniferous, and 9) miscellaneous forest. Forests grouped within the subalpine zone coniferous and miscellaneous classifications were characterized by similar environmental conditions and those forests that did not fit in any other category, respectively.

• 유기물자원화
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• 제4권1호
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• pp.23-31
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• 1996

가정에서 분리수거한 쓰레기와 혼합쓰레기 및 퇴비화 과정중에 있는 쓰레기의 중금속 농도를 측정하였다. 카드뮴의 농도는 봄철에 8 mg/kg 쓰레기, 겨울철에 13 mg/kg 쓰레기였다. 중금속의 농도는 월별로 큰 차이를 보였으며 1월과 2월, 4월, 5월에는 카드뮴의 함량이 부산물 퇴비의 기준인 5 mg/kg 쓰레기의 농도를 초과하였다. 가정쓰레기가 혼합되기 전 분리수거된 음식쓰레기의 퇴비화 과정중에 카드뮴의 함량을 측정한 바, 봄철과 겨울철에 부산물 퇴비화의 기준치를 초과하였다. 분리수거된 가정쓰레기에 수분조절제로 첨가된 석탄회는 퇴비중의 중금속 함량을 낮추는 효과가 있었다. 소형 퇴비화 용기에서 1개월 퇴비화한 음식쓰레기를 야외에서 야적하여 숙성시켰는데, 이 기간동안에 중금속의 축적은 일어나지 않았다.

• 한국수산과학회지
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• 제47권5호
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• pp.474-481
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• 2014

This study examined the effect of pretreated sandfish Arctoscopus japonicus meat as a surimi complex for preparing sandfish flavored fish paste. To prepare the sandfish-flavored paste, fine chopped sandfish meat including backbone was added in a ratio of 0 to 50 wt.% to thawed Alaska pollock Theragra chalcogramma surimi to make a mixed surimi gel. To prepare the sandfish-flavored paste, the mixed surimi was ground with salt using a silent cutter, mixed with starch and stabilizers 0.2% transglutaminase and gluconolactone 0.3%, stuffed in a rectangular container, left for 3 h at $25^{\circ}C$, cooked in hot water for 30 min at $90^{\circ}C$, and finally chilled for 20 min at $4^{\circ}C$. The effects of the pretreatment of sandfish meat were investigated by analyzing the quality of the paste produced. The proximate composition of FP (fish paste containing 40% steam-cooked sandfish meat and 0.3% gluconolactone) was moisture 76.1%, crude protein 12.0%, crude fat 3.8%, carbohydrate 6.1%, and ash 2.0%. The major minerals in FP were Na (23.77 mg/L), Mg (1.46 mg/L), Zn (1.04 mg/L), and Fe (0.41 mg/L), and the major free amino acids were taurine, anserine, alanine, and glutamic acid. The monounsaturated fatty acid content of FP was 566.22 mg%, and the polyunsaturated fatty acid content was 498.43 mg%. The n-3 fatty acid content was 398.01 mg%, and C20:5n-3 (218.85 mg %) was a major component.

• 한국세라믹학회지
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• 제53권2호
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• pp.215-221
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• 2016

In this study, the utilization of the by-products of various industries was examined using raw materials of CSA high-functional cement such as coal bottom ash, red mud, phosphate gypsum, etc. Technology to improve energy efficiency and reduce $CO_2$ was developed as part of the manufacturing process; this technology included lower temperature sintering ($150{\sim}200^{\circ}C$) than is used in the OPC cement manufacturing process, replacement of CSA cement with the main raw material bauxite, and a determination of the optimum mix condition. In order to develop CSA cement, a manufacturing system was established in the Danyang plant of the HANIL Cement Co. Ltd., in Korea. About 4,200 tons of low purity expansion agent CSA cement (about 16%) and about 850 tons of the lime-based expansion agent dead burned lime (about 8%) were produced at a rate of 60 tons per hour at the HANIL Cement rotary kiln. To improve the OPC cement properties, samples of 10%, 13%, and 16% of CSA cement were mixed with the OPC cement and the compressive strength and length variation rate of the green cement were examined. When green cement was mixed with each ratio of CSA cement and OPC cement, the compressive strength was improved by about 30% and the expansibility of the green cement was also improved. When green cement was mixed with 16% of CSA cement, the compressive strength was excellent compared with that of OPC cement. Therefore, this study indicates the possibility of a practical use of low-cost CSA cement employing industrial wastes only.

• 한국초지조사료학회지
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• 제14권3호
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• pp.215-222
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• 1994

This experiment was conducted to find out the response of orchardgrass (Dactylis glorneruta L.) varieties to grazing at the condition of monocultures and mixed pastures on the field of Livestock Experiment Station at Suwon from Sep. 1989 to Oct. 1991. The varieties of orchardgrass used in this experiment were Potomac, Hallmark and Syn. No. 2 as a early maturing type, and Lidacta, Rancho and Syn. No. 10 as a late maturing type. The results obtained were as follows: 1. Herbage utilization of mixture with Hallmark variety(T2) was the highest as 78.2% and that with Rancho variety(T5) was the lowest as 70.2%. but there was no difference(P>0.05). Mixtures with early maturing varieties(T1, T2 and T3) were higher as 77.4% than those with late varieties(T4, T5 and T6) as 72.9% in herbage utilization. In monocultures Rancho variety(T5) was the highest as 68.6% and Lidacta variety(T4) was the lowest as 58.8%, and mixtures with early maturing varieties(T1, T2 and T3) as 66.6% were higher than those of late(T1, 72 and 73) as 64.6%. 2. The content of crude protein of 6 mixed pastures ranged from 19.7% to 22.8%, and those of ether extracts, crude fiber, crude ash and nitrogen free extract were 6.6 to 7.5%, 24.9 to 26.2'76, 1 1.5 to 1 1.9% and 33.6-35.4 8, respectively, But there were not different significantly(P>0.05). In monocultures, significant difference by variety was observed in crude protein content(P<0.05). 3. In botanical composition, there was just a little different among 6 mixtures, having 90% or more in grass percentage. The percentages of each orchardgrass varieties were decreased, but those of perennial ryegrasses were increased as grazing sesson was progressed in all treatment.

• 한국초지조사료학회지
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• 제32권4호
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• pp.369-378
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• 2012

This study was performed out to investigate the influence of the mixed application of chemical fertilizer (CF) and liquid swine manure (LSM) on the growth characteristics, dry matter yield, amino acids, minerals, and free sugars in cultivating silage corn on paddy soils. The field experiment was designed in a randomized block design of 3 repetitions with CF 100% treatment (C), CF 70% + LSM 30% treatment (T1), CF 50% + LSM 50% treatment (T2), CF 30% + LSM 70% treatment (T3), and LSM 100% treatment (T4). At this time, the application of LSM was based solely on the nitrogen. Ear length, ear circle, stem diameter, and stem hardness of the silage corn did not show significant differences between treatments. Fresh yield, dry matter yield and TDN yield were highest in T3, whereas the lowest in C treatment (p<0.05). Crude protein, crude fat, and crude ash content were significantly higher in T1, C, and T4 treatment, respectively (p<0.05). However, NDF, ADF and crude fiber content did not show significant difference between treatments. The total mineral content decreased significantly (p<0.05) as the LSM application rate increased. Total composition amino acid content was higher in the order of T1 > T2 > C > T4 > T3 treatment (p<0.05). Free sugar content was higher in the order of T1 > T3 > T4 > T2 > C treatment (p<0.05). Based on the above results, suggests that the mixed application of chemical fertilizer 30~50% and LSM 50~70% (T2 and T3) is the most effective, considering the yield performance and the content of sugar degree and free sugar affecting silage.