• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2015년도 추계 학술논문 발표대회
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• pp.113-114
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• 2015

This paper is to investigate the effect of poor quality aggregate source used in Korea on the mixture proportion and strength development of the high strength concrete fixed at 450 kg/m3 of cement contents. For aggregate kinds, good quality crushed stone from KS certified manufacturer and low quality crushed stone from non certified construction field are used. For fine aggregates, river sand, land sand, sea sand and mixed sand are also used. It is found that the use of low quality aggregates resulted in an increase of water demand considerably due to poor gradation of aggregate and excessive fine particles. Test results indicate that the use of low quality aggregate also decreases the compressive strength compared with that of good quality aggregate.

• 한국안전학회지
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• 제25권3호
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• pp.78-82
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• 2010

This study is to test insulation mortar mixed with wastepaper and sawdust to find out its insulation performance. Therefore, wastepaper and sawdust have been added to normal mortar. They are analyzed for the above purpose using compressive strength and insulation performance. It is found that the more wastepaper and sawdust will be mixed, the lower heat conductivity will be taken. Wastepaper and sawdust mixture will be more 2.0% then the insulation mortar quality can be compatible with the 3rd kind of the standard. Optimal mixture for insulation will be wast paper:sawdust=4:6. Cohesive test of materials showed that test material has stronger than stand are $0.10N/mm^2$. It is satisfactory the test result showed a range of $0.12{\sim}0.15N/mm^2$ from the test result. Optimal mixture of wastepaper and sawdust have been found out from the study comprehensively, exclusive of the proportion of wastepaper:sawdust = 8:2. It is thought that standard of length deformation; 0.5% is reasonable. This means that deformation of mortar itself can be considered. But it is also Shown that water mixture has also been sharply changed at first flow test. Therefore, it is thought that absorbed water content in the material gave considerable effect to variation rate.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2012년도 춘계 학술논문 발표대회
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• pp.77-79
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• 2012

This study is to assess the differences between concrete having only one of fine aggregates such as crushed fine aggregates, sea sand and blast furnace slag in it and concrete having mixture of two kinds of those fine aggregates in it in order to find out how to deal with the lack of some aggregates. The findings are as follows. In terms of slump, the concrete containing sea sand and blast furnace slag has very low slump values while the concrete having the mixture of crushed fine aggregate and the other fine aggregates showed better workability. In terms of compressive strength, the concrete containing the mixture of two kinds of aggregates showed higher compressive strength. Accordingly, it is likely that the concrete containing the mixture of crushed fine aggregate, sea sand and blast furnace slag is better than the concrete with only one kind of fine aggregates in terms of the usability.

• Korean Chemical Engineering Research
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• 제50권2호
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• pp.223-228
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• 2012

ABS와 폴리에틸렌(Polyethylene, PE) 및 ABS-PE 혼합물의 저온열분해를 회분식 반응기를 이용하여 상압 및 $450^{\circ}C$에서 실행하였다. 열분해 시간은 20~80분까지 하였고 열분해로 생성된 성분은 지식경제부에서 고시한 증류성상온도에 따라 가스, 가솔린, 등유, 경유, 중유로 분류하였다. ABS와 PE의 혼합 폐플라스틱의 열분해 전환율은 PE의 함량이 증가할수록 증가하는 것으로 나타났다. 열분해생성물의 수율은 PE의 함량이 높을수록 중유 > 가스 > 가솔린 > 경유 > 등유 순으로 회수되었다.

• 농업생명과학연구
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• 제44권3호
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• pp.7-14
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• 2010

Alternative subirrigation way, capillary wick system (CWS) was tested to reduce labor cost, waste water, contamination of ground water, and use of fungicide compared to overhead irrigation system (OIS). CWS helped reduce remarkably the working hours for watering from 4 hours in OSI to just 5 minutes. Labor cost was saved 98% in CWS compared to OIS. By the physical characteristics of various growing media, 1 coconut coir+2 perlite (v/v) mixture was selected because it had an ideal distribution of three phase, e.g. 1 solid: 1 liquid: 2 gas phase. Medium mixture containing scoria had so high bulk and particle density to hurt root. In bark-containing medium, the liquid phase and the percent saturation of liquid phase with time elapsed was lower than that of other mixture. It meant that the mixture contained very low level of water. Application of CWS for cyclamen pot production played an important role in reducing the incident of fusarium wilt symptom from 18% in conventional over watering system to 4%. Cyclamen pot irrigated by capillary wick had shorter petiole and more leaves than those by overhead watering. As a result, this system was highly beneficial to get uniform pot products with high quality. It improved water and nutrient solution efficiency relative to conventional overhead irrigation system (OIS).

• 한국초지조사료학회지
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• 제39권3호
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• pp.127-131
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• 2019

The effects of lactic acid bacteria (LAB) mixtures on low moisture Italian ryegrass (IRG) silage fermentation was evaluated in field conditions. The experiment was categorized into two groups: Un-inoculated (Control) and Inoculated with LAB mixture for four storage periods (45, 90, 180, and 365 days, respectively). Silage inoculated with the LAB mixture had the lowest pH with highest lactic acid production than the control from beginning at 45-365 days at all moistures. Higher LAB counts were observed in inoculated silages than the control silages at whole experimental periods. It is a key reason for the rapid acidification and higher lactic acid production in silages during the storage periods. Overall results suggest that an adding of LAB mixture had positive effects on the increasing aerobic stability of silage and preserved its quality for an extended duration.

• 한국재료학회지
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• 제34권5호
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• pp.235-241
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• 2024

Gas identification techniques using pattern recognition methods were developed from four micro-electronic gas sensors for noxious gas mixture analysis. The target gases for the air quality monitoring inside vehicles were two exhaust gases, carbon monoxide (CO) and nitrogen oxides (NO_x), and two odor gases, ammonia (NH₃) and formaldehyde (HCHO). Four MEMS gas sensors with sensing materials of Pd-SnO₂ for CO, In₂O₃ for NO_X, Ru-WO₃ for NH₃, and hybridized SnO₂-ZnO material for HCHO were fabricated. In six binary mixed gas systems with oxidizing and reducing gases, the gas sensing behaviors and the sensor responses of these methods were examined for the discrimination of gas species. The gas sensitivity data was extracted and their patterns were determined using principal component analysis (PCA) techniques. The PCA plot results showed good separation among the mixed gas systems, suggesting that the gas mixture tests for noxious gases and their mixtures could be well classified and discriminated changes.

• 한국초지조사료학회지
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• 제16권2호
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• pp.147-154
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• 1996

Rye(Secale cereale L.) shows lower dry matter yield and nutrient content when it was harvested before wintering. This study was conducted to investigate how effect forage rape(Brassicu napus Subsp oleifera), which carries early maturity and can be harvested before wintering, on the increase of the forage yield and nutrient content when rye was sown mixed with the rape. Optimum sowing rate of the rye/rape mixture was also pursued in this study. The five treatment of rye single, rape single, ryel20+rape 1Okg/ha, rye84+rape 7kg/ha and rye60+rape 5kg/ha were sown on 2 September 1989. Rape single plot was cut one time(l9 November 1989) and the other plots were cuted two times(19 November 1989 and 20 May 1990). In botanical composition of the mixtures, rape recorded dominant ratio with 64~69% at the autumn cut. The rye84+rape 7kg/ha mixture plot marked the highest dry matter yield with 4.46t/ha among all the experimental plot at the autumn cut(P<0.05). In year total yield of dry matter(t/ha), rye single, rape single, rye120+rape IOkg/ha, rye84+rape 7kg/ha and rye60+rape 5kg/ha marked 13.6, 4.1, 12.7, 12.9 and 11.8, respectively. In crude protein content, the rye single plot was 17.2% at the autumn cut on the other hand the mixture plots showed increasing tendency with 18.0~19.9%. In crude fiber content, the mixture plots were remarkably lower than rye single plot. In year total yield of crude protein, rye84+rape 7kg/ha mixture plot showed the highest yield with 1.6lt/ha among all the experimental plots. Ratio of crude protein yield to crude fiber yield, rye84+rape 7kg/ha tended to be higher than the other mixture plots. It is confirmed that the rye/rape mixture can produce more forage than the rye single cropping when they are harvested in late autumn, besides the mixture forage contains higher crude protein than that rye single forage. It can be said that the rydrape mixture is more useful than the rye single cropping, and optimum sowing rate of the mixture is 84kg/ha of rye+7kg/ha of rape.

• 한국도로학회논문집
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• 제11권4호
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• pp.133-142
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• 2009

본 연구는 지불계수를 이용하여 시험포장 구간의 품질을 평가하고 이에 따른 피로수명의 변화를 분석하기 위해 실시되었다. 특히 품질관리가 어려운 아스팔트 함량을 지불규정 기준인자로 선정하여 지불계수를 산출하였다. 먼저 아스팔트 함량이 피로수명에 미치는 영향을 확인하기 위하여 아스팔트 함량에 따른 피로수명의 연관성을 분석하였다. 이후 총 2회에 걸쳐 시험포장 구간에서 시료를 채취해서 지불계수를 산출하여 시험포장 구간의 품질을 평가하였으며, 지불계수에 따라 시험포장 구간의 품질에 차이가 있음을 확인 할 수 있었다. 시험포장 구간에 포설된 아스팔트 혼합물을 이용하여 시편을 제작, 피로수명을 분석하였다. 그 결과 지불계수가 높은 시험포장의 피로수명이 월등히 높음을 확인할 수 있었다. 이는 통계이론을 이용한 지불계수가 실제 포장의 피로수명을 반영한다는 것을 의미한다고 사료된다. 또한 시험포장 구간에 아스팔트 혼합물을 납품한 플랜트의 배합보고서와 동일한 시편을 제작하여 휨 피로시험을 실시하여 1, 2회차 시험포장의 피로수명들과 비교하였다. 그 결과 배합보고서를 기초로 제작한 시편의 피로수명이 시험포장 구간의 피로수명에 비해 월등히 높음을 알 수 있었다. 이는 입도나 기타 요인에 따른 공용성 감소현상이 발생 할 수 있음을 나타내는 것이라 사료된다. 따라서 지불규정을 적용중인 미국과 같이 입도, 공극률 등을 지불규정 기준인자로 선정하여 최종적인 지불계수를 산출하는 것이 보다 정확한 도로포장의 품질을 평가할 수 있을 것이다.

• 한국작물학회지
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• 제36권4호
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• pp.351-359
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• 1991

우리나라에서의 미곡의 유통은 통일계와 일반계는 구분되어 이루어지고 있으나 식미가 다른 품종간에는 대부분 구분되지 않고 혼합되어 관리ㆍ유통되고 있다. 그러나 쌀의 식미는 품종간에 차이가 크고 국민들은 양식미쌀을 선호하므로 저식미쌀에 찹쌀, 또는 고식미쌀을 일정비율 혼합하여 식미향상효과를 얻을 수 있는지와 밥맛이 다른 품종들의 쌀을 일정비율로 혼합했을 때 밥맛에 미치는 영향을 밝히고자 하였다. 시료는 1987년 및 1989년산 통일계벼, 1990년 고성 및 부여산 일반계, 1989년산 통일계 삼강벼. 일반계낙동벼. 1990년산 추청벼, 동진벼 및 진부10호를 식미관능검사 1주일 전에 12분게로 도정하여 사용하였고 시판되는 최고가의 이천쌀과 일반계 찹쌀 상품을 공시하였으며, 식미관능검사는 국립농산물검사소 검사반과 작물시험장 미질 검정실에 의해 실시하였다. 그 결과는 다음과 같이 요약된다 1. 저식미찰(일반계)에 시판 고식미쌀을 중량비 80%까지 혼합하여도 식미향상은 없었으나 동진벼쌀(고식미)을 80% 혼합했을 때에는 동진벼쌀과 동등한 평점을 얻는 식미향상효과가 있었다. 중식미쌀에 시판 시판 고식미쌀을 80% 혼합한 경우는 식미가 크게 향상되었다. 2 식미가 불량한 통일계 고미('87, ＇89년산)에 시판되는 일반계 찹쌀상품을 20% 혼합하였을 때 식미가 향상되었으나, 중하위 식미의 통일계 중상위 식미의 일반계쌀에는 찹쌀 20% 혼합시에도 유의적 효과가 인정되지 않았다. 3. 중위 및 상위 식미품종인 낙동벼, 동진벼, 추청벼 간 여러가지 비율로 혼합한 경우 단일품종과 비교하여 일정한 경향의 유의적 식미 변화가 인정되지 않았다.