• Elastomers and Composites
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• 제49권4호
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• pp.305-312
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• 2014

대부분 군사용 초음속 전투기는 후기 연소기를 사용한다. 후기 연소기는 초음속 비행, 이륙, 전투 상황에 대해 비상 임무 수행을 가능하게 하는 중요한 역할을 한다. 최근 전투기 J85-GE-21 터보제트 엔진 후기 연소기 연료펌프의 내부 피스톤 패킹고무에서 반복적인 연료 누출 결함이 발생하였다. 이러한 결함은 두 제조사 중 한 제조사의 부품에서만 발생하였다. 따라서, 결함발생 원인을 제조사가 상이한 정상품 및 결함품에 대하여 다양한 비교 분석방법을 통하여 조사하였다. 결함분석에는 팽윤 또는 팽윤도, 총 황함량, 폴리머 확인, 카본블랙 함량 및 표면적, 경도와 같은 분석방법이 적용되었다. 결론적으로, 반복적인 연료 누출 결함의 주요 원인은 보강제 카본블랙의 함량 미달로 확인되었으며, 더불어 표면적이 작은 카본블랙과 함량이 낮은 황 적용이 결함원인에 부가적인 영향을 준 것으로 확인되었다.

• The International Journal of Costume Culture
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• 제5권2호
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• pp.53-65
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• 2002

Morphology of polyester fiber was physically modified by solvent treatment. PET fiber was treated with N,N-dimethylformamide (DMF) at 100, 120, $140^{circ}C$ for 10 minutes without tension. The structural changes in the morphology of DMF-induced modified PET fiber were FTIR and SEM analysis. Also dyeing behavior of DMF-treated polyester fibers with various disperse dyes was studied to detect changes of amorphous area in fine structure. DMF treatment resulted in increases in total void content, degree of crystallinity, trans isomer content, chain folding, segmental mobility and molecular packing, but it resulted in decreases in amorphous orientation, intermolecular forces and individual void size through longitudinal shrinkage, lateral welling and removal of oligomers. Void-size distribution could be estimated from the dye uptake with various sizes of disperse dyes. In contrast to the large increases in dye uptake with small dye molecules, there is no and little dye uptake with the bulkiest dye, which means that void size is bigger or smaller than the volume of each dye. Diffusion rates of dye molecules showed increases. This dyeing study revealed that the disperse dyeing is very effective method for characterizing the internal morphology of polyester fiber.

• 한국작물학회지
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• 제47권
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• pp.135-139
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• 2002

The standard of quality was required to promote the consumption of potato and produce the high quality processing products. It will contribute the stability for processing products and the marketability of potato. The quality was determined based on size of tuber and content of dry matter. Even though the criteria of potato quality was involved many characters of tubers, the most important things were grading and packing of potato to create the consumption. For processing of raw materials, the standard of tubers had create between producer and processor according to size of tuber and content of dry matter. The evaluation of quality was performed over the standard to enhance the control of quality. In addition, the seed potato should be taken the evaluation to disease in the field during the period of cultivation and managed under the strict regulation in storage before release to farmer. Then, the producer of seed potato will make a good relationship to farmer with high quality tubers.

• 한국식품과학회지
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• 제12권1호
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• pp.53-58
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• 1980

건조(乾燥) 고추의 변색(變色) 요인(要因)을 구명(究明)키 위(爲)하여 수분(水分) 활성(活性), 광선(光線), 산소(酸素) 및 온도(溫度)를 달리 했을 때의 capsanthin의 소장(消長)과 또 몇가지 구장재(句裝材)로 가루, 원형(原形) 및 원형(原形) 압축(壓縮) 상태(狀態)로 포장(包裝)하여 capsanthin 양(量)과 색도(色度)에 관한 시험(試驗) 결과(結果)는 다음과 같다. 1. 고추의 capsanthin에 미치는 상온하(常溫下)($25^{\circ}C$)의 한계(限界) 수분(水分) 활성(活性)은 0.75이었다. 2. Capsanthin의 감소(減少)는 적외선(赤外線), 백열등(白熱燈) 하(下)에서 보다 자외선(紫外線) 이 심했다. 3. Capsanthin의 질산(窒素) 가스 내(內)에서는 거의 감소(減少)가 없었고 공기(空氣) 내(內)에서 심함 감소(減少)가 있는 것으로 보아 고추의 변색(變色)은 주(主)로 산화(酸化) 작용(作用)에 기인(基因)하는 것으로 본다. 4. $9{\sim}11$월(月)의 상온(常溫)과 저온(低溫) 저장(貯藏) 시(時)에는 포장(包裝)된 고추의 capsanthin의 변화(變化)는 별로 차이(差異)가 없었다. 5. 형태(形態) 별(別) 3개월(個月) 저장(貯藏) 시험(試驗) 결과(結果)는 capsanthin 양(量)과 색도(色度)는 가루 저장(貯藏)이 가장 높았다. 6. 포장(包裝) 재료(材料) 별(別) 밀봉(密封) 저장(貯藏) 시험(試驗) 결과(結果)는 투수성(透水性)과 투기성(透氣性)이 없는 재료(材料)가 P.E.보다 capsanthin 양(量)과 색도(色度)가 높았다.

• 한국식품영양과학회지
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• 제3권1호
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• pp.29-34
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• 1974

1) It was found that melons stored at $20^{\circ}C$ were deteriorated mainly by phytophthora spot and the limits for commercial purpose were 6 days for the control and 4 days for the film packed sample. First of all, alternaria rot was produced after 8 days in control group and each group had cold-stroage hindrance after 20 days. The limits for commercial purpose determined by general appearance were 14 days for the control, 18 days for the 0.02mm and 16 days for the 0.04 mm group. 2) Seven to 8% of weight decrease was the limit of commercial purpose by general appearance. The amount of $CO_2$ excretion was decreased in $20^{\circ}C$ group and increased drastically with deterioration. The amount of $CO_2$, excretion during storage at $2^{\circ}C$ was about $\frac{1}{5}\;to\;\frac{1}{6}\;of\;20^{\circ}C$ 3) The usage of sugar for the substrate of respiration during storage was small and large amount of acids was used for this purpose. The sugar content was decreased with deterioration but acids were increased. The reducing sugar content was decreased and non-reducing sugar content was increased during storage.

• 콘크리트학회논문집
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• 제26권1호
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• pp.23-34
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• 2014

초고성능 콘크리트(UHPC)를 현장에서 타설 하기 위해서는 타설 장비, 배근 상태, 타설 환경 등 현장 조건을 고려한 유동성 조절이 필요하다. 구성 재료와 배합비가 최적화된 UHPC 제품에서 유동성 조절을 위해 현실적으로 변경 가능한 방법은 물-결합재 비(W/B) 또는 고성능 감수제 혼입률(SP/C)을 조절하는 것이며, 경제적 이유로 강섬유 혼입률도 변경 할 수 있다. 일반 콘크리트와는 달리 UHPC는 아주 작은 재료와 배합비 변화에도 굳기 전 또는 굳은 성능에 많은 차이를 나타낸다. 따라서 이 연구에서는 이러한 요인들이 UHPC의 슬럼프 플로와 공기량에 미치는 영향, 그리고 인장 및 압축 성능에 미치는 영향을 알아보았으며, 슬럼프 플로와 공기량과의 선형적인 상관관계를 이용하여 이러한 성능들을 예측할 수 있는 식을 유도 하였다. UHPC의 특성 중 하나인 자기 충전성을 만족하는 조건에서 압축강도에 관한 최적 W/B와 SP/C는 각각 16.8%와 3%로 결정 되었으며, 이러한 조건에서 측정된 공기량은 3.2~4.2%로 이 범위에서의 공기량은 압축강도에 영향을 미치지 못하는 것으로 나타났다. 휨 인장강도에 있어 W/B와 SP/C는 무시할 만큼 작은 영향을 미쳤으며, 상온 양생한 UHPC의 경우 섬유 혼입률이 휨 인장성능을 지배 하는 것으로 평가 되었다. 다만, 체적비로 1%의 강섬유가 혼입된 시편의 경우 섬유가 혼입되지 않은 시편과 달리 균열 후 연성적인 거동은 보였으나, 강도 증진에는 효과가 없는 것으로 나타났다. 반면, 체적비 2%의 강섬유가 혼입된 시편은 강도와 연성을 크게 증가시켰다.

• 한국연초학회지
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• 제13권1호
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• pp.61-68
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• 1991

The moisture contents of threshed leaf tobacco during aging storage were very important factor for the improvement or deterioration of leaf quality. Decay and carbonization of leaf tobacco were mainly controlled by moisture contents during storage. The influence of moisture contents on the decay and carbonization of threshed leaf tobacco (Flue-Cured, Var. NC 82. AB3O-1 grade) were examined during 1 year. The moisture contents of leaf tobacco were treated to 3 kg as 12% (controle), 16%, 20% and 24% after redrying, respectively, These tobacco were put into center of carton box containing about 200kg with 12%'s tobacco, and then packed and stored from June, 1988 under natural weather condition in warehouse at Ock-Cheon threshing plant. Samples were taken from dissected carton box at 0, 1, 2, 4, 7 and 12 months after moisture treatment and Racking time, and some chemical properties were investigated at every sampling time. In results of inducement to decay and carbonization of leaf tobaccos during 1 year's storage by moisture treatment. decayed leaf was appeared but carbonized leaf did not. Calorification and decayed leaf occurred at high moisture contents above 20%, and these phenomena were appeared between 30 and 150 days after moisture treatment and packing. High moisture content leaves (above 20%) caused nearby other leaves to be sunk with high moisture content. Nicotine and calcium contents were increased to 20%~30% and 10%~22%, respectively, but total sugar contents was decreased to 40%~60% by moisture treatment(20% ~24% ).

• 한국환경보건학회지
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• 제23권3호
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• pp.85-90
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• 1997

The objective of this study was to investigate biodegradation of TPA(terephthalic acid) and EG (ethylene glycol), treatment efficiency of polyester weight loss wastewater and microbial characteristics by aerated submerged biolfilm(ASB) p.rocess. In a batch reactor, pH increased from 7.0 to 8. 5 in the biodegradation of TPA. Whereas, in case of EG, decreased from 7.0 to 5.2. COD concentration rapidly decreased within 24hr in the biodegradation of TPA and EG. COD removal velocity constant(k) were 0.065-0.088 hr$^{-1}$. The biodegradation velocity of TPA was 1.4 times faster than that of EG. The ratio of suspended biomass to the total biomass in the reactor was 18.3-33.3%, increased as a high ratio of EG content. Biofilm thickness, biofilm dry density and attached biomass were 346-432 $\mu$m, 41.8-61.9 mg/cm$^3$, 1.45-2.67 mg/cm$^2$, respectively. There values increased as a high ratio of TPA content. In the hydraulic retention time of 36 hr, organic loading rate of 4 kgCOD/m$^3\cdot$ day and packing ratio of 70%, the effluent concentrations of TCOD, SCOD in a continuous flow reator were 1,388 mg/l, 147 mg/l and removal efficiencies were 77%, 97.6%, respectively.

• Preventive Nutrition and Food Science
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• 제10권3호
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• pp.207-213
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• 2005

Molecular structures and functional properties of starches isolated from normal, waxy, and zero amylose barleys were examined. Amylopectins from zero amylose starch had the largest molecular weight $(M_w)$, whereas those from high amylose starch, the smallest. A good correlation between the $(M_w)$ and the radius of gyration $(R_g)$ was observed among amylopectins from various starches, indicating similar polymeric conformation in solution even with the differences in the $(M_w)$. The debranched amylopectin molecules from different types of barley starches exhibited similar profiles, implying that the packing geometry of double helices in the different types of barley starches may be similar. Zero amylose starch showed the highest peak viscosity (326 RVU) in RV A viscograms at lower pasting temperature $(67.6^{\circ}C)$, compared to normal and high amylose starches. Relationship between RVA peak viscosity and amylose content suggested that the presence of amylose inhibited the development of granular swelling of barley starches during cooking. A rapid retrogradation, traced by differential scanning calorimetry (DSC) and strain-controlled rheometry, occurred in the high amylose starch sample during storage, while zero amylose starch showed a very good resistance to retrogradation, indicating excellent storage stability.

• 한국식품저장유통학회지
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• 제1권2호
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• pp.81-86
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• 1994

This study examined the quality change of red peppers during storage at various temperatures and humidities. It was observed that red peppers showed mold at aw 0.75(>25% water content), discoloration at aw 0.33(<10%) and browning at aw 0.75(>19%). The most ideal condition of the storage for red peppers was a 13∼15% water content and 60${\pm}$5% RH. The storage life for whole red peppers were 2.0 months at 40$^{\circ}C$, 13.6 months at 25$^{\circ}C$, 27.3 months at 15$^{\circ}C$, 30.0 months at 10$^{\circ}C$, and 65.0 months at -3$^{\circ}C$. During any storage period above, level of capsanthin, browning and capsaicin were changed for whole peppers. Browning appeared to be a crucial factor for marketable quality of stored red peppers. It was found that the level of capsaicin & capsanthin have a miner relationship with marketable quality for consumer. Storing red peppers in nitrogen and vacuum atmosphere packing condition was found to be better than storing them in air at various temperatures in terms of storage life and quality maintenance. The nitrogen gas packaged red peppers kept longer shelf life and better quality compared with vacuum packaging.