• 한국작물학회지
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• 제44권3호
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• pp.288-295
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• 1999

Nineteen japonica and Tongil-type rices were selected from seventy nine Korean and Japanese rice cultivars grown in 1989 based on the water uptake behavior of milled rice under the room temperature and boiling conditions. The selected rice cultivars were investigated for water absorbability and some physicochemical characteristics of milled rice, proper water amount for cooking and sensory evaluation of cooked rice. The relationships among the tested grain properties were also examined. The highest varietal variation of water uptake rate was observed at twenty minutes after soaking in water. The maximum water uptake of milled rices at room temperature occurred mostly at about eighty minutes after soaking in water. Newly harvested rices showed a significantly lower water uptake rate of milled rice at 20 minutes after soaking, a relatively higher maximum water absorption ratio under the room temperature, and the less water uptake and volume expansion of boiled rice compared with the one-year old rice samples. The water uptake rate and the maximum water absorption ratio showed significantly negative correlations with the K/Mg ratio and alkali digestion value(ADV) of milled rice. The rice materials showing the higher amount of hot water absorption exhibited the larger volume expansion of cooked rice. The harder rices with lower moisture content revealed the higher rate of water uptake at twenty minutes after soaking and the higher ratio of maximum water uptake under the room temperature condition. These water uptake characteristics were not associated with the protein and amylose contents of milled rice ansd the palatability of cooked rice. The water/rice ratio(in w/w basis) for optimum cooking was averaged to 1.52 in dry milled rices (12% wet basis) with varietal range from 1.45 to 1.61 and the expansion ratio of milled rice after proper boiling was averaged to 2.63(in v/v basis). The water amount needed for optimum cooking was the lowest in Cheongcheongbyeo (Tongil-type rice) and the highest in Jinbubyeo, and the amount could be estimated with about 70% fittness by the multiple regression formula based on some water uptake characteristics, ADV and amylose content of milled rice as the independent variables. Nineteen rice cultivars were classified into seven groups based on scatter diagram projected by principal component analysis using eight properties related to water uptake and gelatinization of milled rice.

• Journal of Biosystems Engineering
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• 제33권2호
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• pp.115-123
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• 2008

This study was conducted to develop an automatic soil water content control system for greenhouse, which consisted of drip irrigation nozzles, soil water content sensors, an on/off valve, a servo-motor assembly and a control program. The control logic adopted in the system was Ziegler-Nichols algorithm and rising time, time constant and over/undershoot ratio as control variables in the system was selected and determined by various control experiments to maintain small delay time and low overshoot. Based on the experimental results, it was concluded that the control system developed in the study could replace the unreliable conventional greenhouse soil water management.

• 한국토양비료학회지
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• 제44권2호
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• pp.168-175
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• 2011

토양수분포텐셜이 복분자 생육에 미치는 영향을 조사하기 위하여 복분자 시설하우스에서 -5 ~ -40 kPa 수준으로 토양수분을 처리하였다. 시설하우스내의 토양유효수분은 5.6%이었고, 수분포텐셜에 따라 토양수분함량이 높아지면 토양 pH와 치환성 Ca은 증가하였고, 치환성 K와 전질소 함량은 감소하였으며, 유기물함량은 수분처리 9일 이후부터 감소하였다. 수분포텐셜과 토양수분함량 간에는 y = 96.534 - 20.28In(x)의 지수함수 근사식이 성립되었다. 수분포텐셜이 -20 kPa (토양 수분 27.5%) 이상이면 복분자 잎의 엽록소 함량이 감소하였고 질소흡수가 억제되며, P 함량은 수분공급 시간에 따라 증가하였다. 수분포텐셜 -20 kPa 이상의 수준으로 7일 이상이 경과하면 뿌리활력이 급격히 감소되어 생육이 위축되었다. 지상부에 대한 뿌리비율 (T/R률)은 수분공급 9일까지 급격히 감소하였다. 휴면기의 복분자 줄기와 뿌리의 탄수화물 함량은 -5 kPa과 -10 kPa 처리구에서 가장 낮아 동해 위험도가 가장 높았다.

• 콘크리트학회논문집
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• 제14권2호
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• pp.164-170
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• 2002

본 연구는 고로슬래그 미분말을 혼입한 폴리머 시멘트 모르타르의 강도, 흡수율, 중성화 깊이 및 염화물 이온 침투 깊이에 미치는 폴리머-결합재비 및 고로슬래그 치환율의 영향에 대해 고찰하였다. 그 결과, 폴리머 시멘트 모르타르의 휭 및 압축강도는 폴리머-결합재 비 및 고로슬래그 치환율의 증가에 따라 증가하고 고로슬래그 치환율 40 %에서 최대치에 달하는 것으로 나타났다. 폴리머 시멘트 모르타르의 방수성, 중성화 및 염화물 이온 침투에 대한 저항성은 폴리머-결합재비 및 고로슬래그 치환율의 증가에 따라 감소하는 경향을 보였다. 따라서 폴리머 종류에 관계없이 폴리머 시멘트 모르타르에 고로슬래그 미분말을 혼입할 경우에는 고로슬래그 치환율은 40% 정도라고 할 수 있다.

• 콘크리트학회논문집
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• 제12권4호
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• pp.103-111
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• 2000

The influence of the improvement of grain shape of the coarse aggregate to the unit powder content of concrete and the fine aggregate ratio for the increase of the flowability and segregation resistance of high performance concrete was examined. According to the experimental results, flowability and compacting of concrete presents best states in the S/a which has the smallest 패야 ratio. The coarse aggregate after improvement of grain shape, that has changed from the 0.68 of spherical rate of disk shape to 0.73, led fine aggregate ratio to be down 6% (i.e from 47% to 41%). The improvement of grain shape of the coarse aggregate also led the lowest unit powder content to be down 60kg/㎥ (ie from 530kg/㎥ to 470kg/㎥). And approximate 10% of unit water content has been reduced as unit powder content was down. However, the compressive strength after the improvement of grain shape of the coarse aggregate decreased to 5% due to decrease of adhesiveness of the aggregate and cement paste.

• Journal of the Korean Wood Science and Technology
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• 제26권4호
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• pp.43-49
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• 1998

The availability of large quantities of waste woods provides an impetus for investigating woody biomass potential uses. Polyurethane (PU) foams are prepared with reacting isocyanates and polyols, and are used. in various industry fields. Thus, lignocellulosic waste raw-materials are proposed as replacement for synthetic polyol to PU foam formulation. In this study PU foams were manufactured from liquefied woods, methanediisocyanate(MDI), catalyst, foaming stabilizer, and viscosity aids. The polyol content, isocyanate.hydroxyl group (NCO/OH) ratio, and water content were varied to evaluate their effects on the foaming and water absorption of the PU foams. Less than 400 Molecular weight. of polyethylene glycol(PEG) and 1 to 3 solvent to woody raw-material ratio were desirable for liquefying woody materials. Liquefying rate was increased with more than 3 % addition of inorganic and organic catalysts and raising reaction temperature more than $150^{\circ}C$. Addition of starch enhanced liquefying of woody materials. Fourty percents of starch resulted in about 90% liquefying rates. Foaming rates were increased with increasing moisture contents of liquefied wood. Moisture contents of 0.6% resulted in 5 time-foaming rates, and seven percents of moisture contents more than 30 time-foaming rates. But, an increase in water content may result in a decrease in cross-links between wood polyol and isocyanate, because the NCO/OH ratio is constant. Increasing moisture contents have significantly decreased density of PU foams. The optimum water content should be about 2.5% or less in this adopted condition.

• 한국식품조리과학회지
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• 제20권5호
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• pp.480-488
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• 2004

The purpose of this study was to determine gain the most desirable mixture ratio for the ingredients of Backhapbyung. Sensory examination and mechanical test were conducted on the texture, water contents and color degree of Backhapbyung with various ratios of liliibulbs powder and sugar added to nonglutinous rice flour. The results of sensory evaluation showed that Backhapbyung composed of put 8% (24g) liliibulbs powder, 40g sugar, 40ml water and 276g nonglutinous rice flour had the highest overall score in terms of acceptability, after-swallowing and taste of flavor, and overall quality preference. Overall among the recipes tested, that with 6% (24g) liliibulbs powder, 40g sugar, 40 ml water and 282g nonglutinous rice flour showed the highest marks in springiness, cohesiveness, gumminess and chewiness. The moisture content was 33.54% nonglutinous rice flour, and 11.8% liliibulbs powder. The overall quality of sensory examination for bitterness was positively correlated with the hardness of sensory examination and the mechanical examination for adhesiveness. The overall quality of sensory examination for chewiness was positively correlated with the moistness of sensory examination and the mechanical examination for cohesiveness. From the above results, the best mixture ratio of Backhapbyung, with a moisture content of 37.18%, is 8% (24g) of liliibulbs powder, 40g sugar, 40ml water, and 3g salt and 276g nonglutinous rice flour.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2002년도 학술.기술논문발표회
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• pp.29-36
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• 2002

High fluid concrete unlike OPC concrete is made with various material, and the phase of fresh concrete is considerably different. In order to understand fluidity phase and mix properties of high fluid concrete, concrete is required to access as suspension structure which consists of aggregate and paste. The focus of this paper is to analyze the test results and quantify the effect of mix proportions of molar and fineness modulus of ,and on the properties of fresh mortar. The effect of water-binder ratio, sand-binder ration, content; of ggbs (by mass of total cementitious materials), and various contents of water reducing agent on the yield stress and plastic viscosity of the mix is studied. Based on the experimental results, the following conclusion; can be drawn: (1) The mixing time needed (or high fluid mortar was approximately two times more than that of ordinary portland mortar. (2) The fluidity phase of mortar could be explained by yield stress of mix and the fluidity of mortar. (3) As the content of ggbs increased, yield stress of mortar was decreased and plastic viscosity of it was increased. (4) For the high fluid mortar, it was appeared that sand-binder ratio should be below 1.5.

• Agricultural and Biosystems Engineering
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• 제7권1호
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• pp.42-47
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• 2006

The objective of this study was to investigate the effects of air-phase germination with water-spraying and anion stimuli on germination ratio, sprout growth and ${\gamma}$-aminobutyric acid (GABA) of brown rice. Air-phase germination method with intermittent spraying water improved germination ratio and sprout growth by about 100% compared with the conventional water-soaking method. Anion radiation was applied during the germination process and improved the germination ratio, sprout growth and color quality of the germinated brown rice. Germination ratio and sprout growth were improved up to 9% with anion radiation, and its brightness was higher than brown rice germinated with no anion radiation. The air-phase germination with water-spraying improved the GABA content of germinated brown rice by about 8-9 times compared with that of brown rice.

• 한국지반공학회논문집
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• 제33권11호
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• pp.5-19
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• 2017

본 연구는 전통적인 다짐관리방법의 문제점을 보완하고자 TDR(Time Domain Reflectometry)을 이용하여 지반의 함수비와 건조단위중량을 측정하는 연구를 수행하였다. 개발된 Flat TDR 시스템의 측정값을 검증하기 위해 여섯 가지 시료를 대상으로 실내실험을 수행하였다. 또한 실내실험을 바탕으로 현장시험을 수행하여 현장 적용성을 검토하였고, 신뢰성을 확보하기 위해 Purdue TDR 시스템과 비교실험을 수행하여 정밀도를 확인하였다. 또한 유한요소해석을 수행하여 Flat 프로브의 영향범위를 확인하였다. 그 결과 약 10cm의 영향범위를 확인하였고, 실내실험결과 함수비는 평균적으로 약 0.4%의 오차를 보이며, 건조단위중량의 경우 약 1.6%의 오차를 보였다. 현장시험의 경우 함수비는 0.8%, 건조단위중량의 경우 2.5%의 오차를 보였다. 실험 결과를 통하여 Flat TDR 시스템의 측정값은 기존의 TDR 시스템보다 정확한 값을 도출하는 것을 확인할 수 있었다.