이 연구에서는 최근 개발된 강섬유 보강 초고성능 콘크리트(UHPSFRC)의 압축연화 거동을 실험을 통해 측정하였다. 압축 연화곡선을 안정적으로 측정하기 위해 실험체의 횡 방향 변형을 제어하여 실험을 수행하였다. 실험에 사용한 UHPFRC의 배 합은 모두 세 가지(M1, M2, M3)이며, 평균 압축강도는 각각 순서대로 131.0, 161.6, 171.5 MPa로 측정되었다. 압축강도와 섬유함유량에 따라 압축연화곡선의 거동이 다르게 나타났다.

In order to develop a sprayable ethylene antagonist, unlike 1-methylcyclopropene (MCP), we synthesized 2-decylcyclopropene-1-carboxylic acid ethyl ester (DCPE) as a derivative of cyclopropene and tested its effect on the flesh softening of ‘Fuyu’ persimmon fruits. The fruits on trees were sprayed with 4·10-4 M DCPE solution before harvest. After harvest, the persimmon fruits were stored at a low temperature for 1.5 months. The ripening progress of the fruits was then evaluated during storage at ambient temperature (20℃). Flesh softening, a measure of ethylene response, was considerably delayed up to 7 days after DCPE treatment. However control fruits was rapidly softened after 3-day storage. The treatment effect of DCPE at 4·10-4 M was also compared to that of 1-MCP at 1 ppm. DCPE was storable at refrigerated conditions for at least one month without any loss. The results show that DCPE could be a potential sprayable agent for the prevention of flesh softening of persimmon fruit.

This study was carried out to investigate the effects of Ca-gluconate (Ca-glu) on fruit firmness and softening enzyme activities of hydroponically grown tomato (Solanium esculentum Mill.). The obtained results revealed that the rate of weight loss was markedly increased from at storage to 5 days after storage (DAS) in control, and was constantly increased until 7 DAS as 4.1% in Ca-glu treatment. Fruit firmness was more rapidly decreased in Ca-glu induced fruit compared to control. Results showed that fruit firmness in control and Ca-glu treated fruit were 0.67 and 0.95 kg좵즤12 mm-1, respectively. In our investigation, no difference was revealed in Hunter…s ‥a… value between control and Ca-glu treated fruit. Total carotenoids content of control fruit were rapidly increased while the Ca-glu treated fruit were gently increased. Lycopene content was higher (63.3 즗g；g-1 FW) in control than Ca-glu treatment (56.8 즗g；g-1 FW). The activity of Polygalacturonase (PG) was rapidly increased with increasing storage period as from 0.4 to 1.2 units whereas the PG activity of Ca-glu treatment was gently increased from 1 to 7 DAS, and rapidly increased from 7 to 11 DAS. However, the pectinesterase (PE) activity was rapidly increased in control fruit, when the storage period was increased, but interestingly, the Ca-glu treated fruit was slowly increased from 1 to 7 DAS, and rapidly increased 7to 11 DAS. ?-galactosidase activity of Ca-glu induced fruit was rapidly increased from 1 to 7 DAS as from 1.6 to 3.0 units, and gently increased from 7 to 11 DAS. ?-galactosidase activity of control were higher than Ca-glu treatment.

팽창재는 콘크리트의 건조/자기수축으로 인한 균열에 매우 효과적인 혼화재료이며 콘크리트 내부 철근에 화학적 프리스트레스를 인가할수 있다. 본 논문에서는 CSA 팽창재에 의해 화학적 프리스트레스가 도입된 모르타르의 인장경화성능을 평가하였다. 철근으로 내부구속이이루어진 철근 모르타르 시편에 대하여 일축인장시험을 수행하였으며, 균열거동 특성과 인장경화 특성을 분석하였다. CSA 모르타르에서는 압축강도 및 탄성계수는 약간 감소하였으나, 화학적 압축응력이 철근에 도입되었으며, 일반 모르타르 부재에 비해 167.5% 초기균열하중이증가하였다. 높은 인장경화특성을 평가하였으며, 기존의 인장연화모델과 실험값을 비교하여 기존 제안식의 보완점을 제시하였다.

탄-소성론에 근거한 콘크리트나 토질과 같은 재료의 파괴 포락선은 주응력을 축으로 하는 공간 좌표계상에서 인장의 등압(hydrostatic stress)축을 향해 기울어진 형태를 가지며 소성흐름이 상관소성흐름 법칙(associated flow rule)에 따라 결정될 경우 콘크리트의 거동 예측시에 과도한 체적 팽창률을 나타내게 된다. 본 논문에서는 콘크리트의 다축응력 하에서의 거동을 예측하기 위하여 비균일 경화(nonuniformh ardening)를 적용한 5계수 파괴 포락선과 등압축 방향 성분의 소성 흐름을 수정하는 비상관 소성흐름 법칙(non-associated flow rule)을 사용하여 비선형 유한요소해석 프로그램을 개발하였으며 신뢰성 있는 연구자의 다축응력 실험결과와 유한요소해석 프로그램의 해석결과를 비교하였다.

저온과 종피연화의 처리방법을 설정하여 둥굴레 종자를 이용한 다량육묘에 필요한 정보를 제공하고자 저온처리기간 (4, 8, 12, 16주), 종피연화(10% KOH, 40분)와 저온의 혼용(混用) 처리방법(處理方法)이 발아(發芽), 소주아(小珠芽) 형성(形成) 및 발아개체 등에 미치는 영향을 조사하였던 바 그 결과를 요약하면 다음과 같다. 1. 발아률(發芽率)과 소주아(小珠芽) 형성률(形成率)은 저온만 처리할 경우 8~12주가 적정 기간으로 판단되었으나 종피연화와 혼용처리(混用處理)할 경우 저온처리기간을 8주 이내로 대폭 단축할 수 있는 것으로 나타났다. 2. 둥굴레 종자의 발아는 종피연화와 저온을 각각 단용처리(單用處理)하는 것보다는 이들의 혼용처리(混用處理)에서 향상되었으며 종피연화처리 효과보다는 저온처리의 효과가 큰 것으로 분석되었다. 3. 발아(發芽) 및 소주아(小珠芽) 형성률(形成率)은 종피연화 처리를 저온 처리 후에 실시하는 것보다는 전에 실시하는 것에서 양호하였고, 근수(根數)에서도 이와 유사한 경향을 보였다.

This study was conducted to understand the characteristics of fruit softening during ripening which causes deep loses in quality of horticultural products during storage and marketing process after harvest. The changes of cell wall components during ripening was investigated. The climacteric rise was between 42 and 49 days after anthesis and then decreased. Ethylene evolution was similar to respiration. The hardness of fruit decreased markedly at this climacteric period and significances of textural parameters among the ripening periods were recognized but the significance between 50 and 55 days after anthesis was not. Sugar components of cell wall polysaccharides were uronic acid, galactose, glucose, arabinose, xylose, rhamnose, mannose and fucose. The contents of arabinose and mannose in alcohol-insoluble solids fraction increased, but other sugars were not changed. In cell wall fraction, the contents of uronic acid, galactose, glucose and arabinose were comparatively high, but galactose, arabinose and ironic acid were decreased markedly during ripening. ironic acid occupied above 75% of total monosaccharide in pectin fraction and decreased markedly during ripening. In acid-soluble hemicellulose fraction, the contents of uronic acid, glucose, galactose and rhamnose were high and they decreased from 50 days after anthesis. The contents of glucose and xylose were high in a alkali-soluble hemicellulose fraction and they decreased markedly at 55days after anthesis.

The cell wall components of fruit include cellulose. hemicellulose, pectin, glycoprotein etc., and the cell wall composition differs according to the kind of fruit. Fruit softening occurs as a result of a change in the cell wall polysaccharides : the middle lamella which links primary cell walls is composed of pectin. and primary cell walls are decomposed by a solution of middle lamella caused due to a result of pectin degradation by pectin degrading enzymes during ripening and softening, During fruit ripening and softening, contents of arabinose and galactose among non-cellulosic neutral sugars are notably decreased, and this occurs as a result of the degradation of pectin during fruit repening and softening since they are side-chained with pectin in the form of arabinogalactan and galactan Enzymes involved in the degradation of the cell wall include polygalacturonase, cellulose, pectinmethylesterase, glycosidase, etc., and various studies have been done on the change in enzyme activities during the ripening and softning of fruit. Among cell wall-degrading enzymes, polygalacturonase has the greatest effect on fruit softening, and its activity Increases during the maturating and softening of fruit. This softening leads to the textural change of fruit as a result of the degradation of cell wall polysaccharides by a cell wall degrading enzyme which exists in fruit.

땅두릅 여룹철 연화재배(軟化栽培) 가능성(可能性)을 검토(檢討)하기 위하여 흑색(黑色) PE와 은색(銀色) 단섬유불직포(短纖維不織布)를 이용하여 5월 정식(定植)을 포함하여 6월, 7월, 8월 정식기(定植期)에 대하여 시험(試驗)한 결과(結果)는 다음과 같다. 1. 수확소요일수(收穫所要日數)는 5월 정식(定植)에서 20일(日)이고 7월, 8월 정식(定植)에서는 15일로 단축(短縮)되었으나 생육기간중(生育期間中)의 적산온도(積算溫度)는 400℃ 범위이었다. 2. 7월 정식(定植)에서 땅두릅 연화수(軟化莖)의 수량(收量)은 고온(高溫)으로 인한 연부현상(軟腐現狀)으로 낮은 경향(傾向)이었다. 3. 각(各) 부위별(部位別) 경도(硬度)는 상위부(上位部)가 연(軟)하고 하위부(下位部)가 단단한 경향(傾向)이고, 저온저장(低溫貯藏) 7일후(日後)에도 신선도(新鮮度)는 유지(維持) 되었다. 4. 5월, 6월 정식재배시(定植栽培時) 18,000천원/ha 이상(以上)의 소득(所得)을 얻을 수 있었다.