• 식품과학과 산업
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• 제53권1호
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• pp.43-55
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• 2020

Most reports demonstrated the substrate specificity-based kinetic properties of chitin or chitosan degrading enzymes. However, there is virtually less information on the high quality and quantity production of chitin or chitosan hydrolysates having a larger than (GlcN)₇ from the hydrolysis of high molecular weight chitosan using specific enzymes and their biological activity. Therefore, the production of such molecules and the discovery of such enzyme sources are very important. Fortunately, the author has established a mass production method of chitosan hydrolysates (GlcN)_n, n=2-13 that have been characterized as a potent antioxidant substance, as well as antifungal and antibacterial activities against Penicillium species and highly selective pathogenic bacteria. In addition, preclinical studies using (GlcN)_n, n=5-25 demonstrated that these molecules played a very important role in maintaining biometric balance. Collectively, it is implicated that the application of these mixed substances to foods with significant biological activity is very encouraging.

• Asian-Australasian Journal of Animal Sciences
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• 제15권11호
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• pp.1606-1610
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• 2002

The dynamics of fermentation were studied with Italian ryegrass ensiled in the laboratory silos. The silos were kept in the room set at 25$^{\circ}C$, and then were opened on 0.5, 1, 2, 3, 5, 7 and 14 days after ensiling, respectively. The samples were taken from three silos at each sampling time for chemical analyses. Mono-and disaccharides composition was determined for glucose, fructose and sucrose by high performance liquid chromatography. The Italian ryegrass silage succeeded to achieve lactate type fermentation; high values of lactic acid (85.83 g/kg) and lactic acid/acetic acid at the end of ensiling (14 day), low values of pH (3.74), acetic acid (5.38 g/kg), ethanol (19.20 g/kg) and $NH_3-N/Total\;N$ (75.84 g/kg), no or only small amounts of butyric acid, valeric acid and propionic acid. The fermentation dynamics showed a fast and large pH decrease caused by a fast and large production of lactic acid during the first 5 days. Mono-and disaccharides composition largely decreased within initial 0.5 day (12 h) of ensiling. Sucrose disappeared rapidly within initial 0.5 day of ensiling, and fructose and glucose contents showed an initial rise during ensiling, and then decreased gradually. These indicated that the enzymes of plant tissue were active within 2 days of ensiling, which caused the initial rise in fructose and glucose from the hydrolysis of sucrose and fructans. After 5 days of ensilage, glucose was consumed completely, suggesting that glucose was the first fermentation substrate. After 2 days of ensiling, sum amounts of lactic acid and remaining mono-and disaccharides proved to be larger than the quantity of mono-and disaccharides in the initial grass. From the facts mentioned above, it was suggested that considerable amounts of lactic acid were produced from some other substrate such as fructans than initial mono-and disaccharides.

• 공업화학
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• 제23권4호
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• pp.394-398
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• 2012

아스트라갈린(AS)은 폴리페놀의 일종인 캠페롤(KR)에 글루코스가 하나 결합해있는 배당체로서, 천연에는 미량만이 존재하고 있다. 최근 tea seed extract (TSE)에 포함되어 있는 camelliaside A (CamA) 및 camelliaside B (CamB)로부터 복합효소인 Mash에 의한 부분가수분해에 의해 AS를 합성할 수 있다는 것이 알려졌다. 본 논문에서는, Mash에 의한 TSE의 선택적 가수분해에 의해 AS를 제조하는 공정에서 반응 온도, 효소량 및 반응물의 농도 등의 변수에 따른 반응성을 검토하였다. 반응 온도, 효소량 등이 증가할수록 AS의 생성 반응은 빨랐으나, 일단 생성된 AS가 급격하게 KR로 변환되는 문제점이 나타났다. 결론적으로, 반응 속도 및 AS의 선택성 측면을 고려하면, $50^{\circ}C$에서 TSE 대비 2배의 Mash를 사용하여 15%의 기질 농도에서 반응을 수행하는 것이 최적인 것으로 나타났다.

• 한국균학회지
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• 제26권1호통권84호
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• pp.20-24
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• 1998

액체종균의 전배양 4일, 본 배양 6일 이하가 적합하였다. 톱밥종균을 사용한 대조구와 비교해 볼 때 YPD액체종균의 경우 배양일수는 $5{\sim}7$일 정도 배양이 빨랐고, 초발이 소요일수는 비슷하였으며 수량은 비슷하거나(배지수분 65%, 50ml 접종), 24%까지(배지수분 65%, 15ml) 증가하였다. PDB액체종균의 경우 배양일수는 비슷하거나(배지수분 55%, 15 ml 접종), $2{\sim}4$일 단축되었고(배지수분 65%, $15{\sim}50ml$ 접종), 초발이 소요일수는 비슷하였으며 수량성은 비슷하거나(배지수분 55%, 15ml 접종) 23%까지(배지수분 65%, 25 ml 접종) 증가하였다. 미강 추출액 액체종균의 경우 배양일수와 초발이 소요일수는 비슷하였고, 수량성은 3%(배지수분 55%, 15ml 접종)에서 38%(배지수분 55%, 50 ml 접종)까지 증가하였다. 참깨박 추출액 액체종균의 경우 균총 형성 숫자는 많았으나 배양일수와 초발이 소요일수는 모두 대조구보다 길어졌고, 수량성도 크게 감소되었다.

• Composites Research
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• 제22권6호
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• pp.45-51
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• 2009

치아의 와동에 수복된 치과용 복합레진을 광(LED) 조사를 통해 경화 수축시키면서 음향방출(acoustic emission, AE)법을 이용하여 와동 벽면과 복합레진 사이의 계면상태를 실시간 해석하였다. 복합레진의 중합 수축에 의해 AE 신호들이 검출되었는데 계면 접착 상태가 나쁜 경우, 경화 수축률이 큰 초기 1분 동안 많은 AE 사상들이 관측되었으며, 이들 AE는 주파수범위가 주로 100-200kHz인 돌발형이었다. 인간치아 재질의 시편에서 발생된 AE 사상수는 스테인리스 스틸 시편보다 적었으나, PMMA 시편보다는 많았고 접착제의 도포 상태가 양호할수록 검출되는 AE 사상수는 적었다. AE 파라미터의 특성은 복합레진과 링재 사이의 접착부에서 발생하는 인장형 균열전파 및 복합레진의 수축에 따른 링재의 압축거동과 관련되었으며, 음향방출법이 치아 수복물의 접착성에 대한 비파괴 검사법으로써 유효함을 알았다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.426-426
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• 2012

The CIGS absorber has outstanding advantages in the absorption coefficient and conversation efficiency. The CIGS thin film solar cells have been researched for commercialization and increasing the conversion efficiency. CIG precursors were deposited on the Mo coated glass substrate by magnetron sputtering with multilayer structure, which is CuIn/CuGa/CuIn/CuGa. Then, the metallic precursors were selenized under high Se pressure by RTP method which included. Se vapor was supplied using Se cracker cell instead of toxic hydrogen selenide gas. Se beam flux was controlled by variable reservoir zone (R-zone) temperature during selenization process. Cracked Se source reacted with CIG precursors in a small quantity of Se because of small size molecules with high activation energy. The CIGS thin films were studied by FESEM, EDX, and XRD. The CIGS solar cell was also developed by layering of CdS and ZnO layers. And the conversion efficiency of the CIGS solar cell was characterization. It was reached at 6.99% without AR layer.

• 상하수도학회지
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• 제8권1호
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• pp.27-33
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• 1994

With the rapid industrialization, an ever-increasing quantity and kind of new organic compounds pose environmental problems due to their toxicity and physiological effect. However, research on the biodegradation of these compounds under anaerobic condition is very limited inspite of its efficiency and economical advantage. In this research, the pH effect on the ring cleavage of phenol under anaerobic condition was investigated, and the theory of phase separation was applied to the degradation of phenol for investigating the role of acidogenic bacteria. Results, obtained from biochemical methane potential(BMP) assay for 15.5 days of incubation, showed that acidic condition was more desirable for phenol degradation than alkaline condition. By both unacclimated methanogenic granular sludge and two mixed cultures, phenol was completely removed within six weeks of incubation with a gas conversion rate of over 86% of theoretical one. However, phenol was not degraded by unacclimated acidogenic culture, and thus it is considered as a syntrophic substrate. In case of phase separated biochemical methane potential(PSBMP) assay, in which acidogenic and methanogenic culture were seeded separately and consecutively, those that had been subjected to normal acidogens for 3 to 4 weeks showed higher gas production than those seeded with sterile or frozen culture.

• 산업공학
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• 제25권2호
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• pp.264-275
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• 2012

The process of semiconductor(IC Package) manufacturing usually includes lots of complex and sequential processes. Many kinds of equipments are installed with the mixed concept of serial and parallel manufacturing system. The business environments of the semiconductor industry have been changed frequently, because new technologies are developed continuously. It is the main reason of new investment plan and layout consideration. However, it is difficult to change the layout after installation, because the major equipments are expensive and difficult to move. Furthermore, it is usually a multiple-objective problem. Thus, new investment or layout change should be carefully considered when the production environments likewise product mix and production quantity are changed. This paper introduces a simulation case study of a Korean company that produces packaging substrates(especially lead frames) and requires multi-objective decision support. $QUEST^{(R)}$ is used for simulation modelling and AHP(Analytic Hierarchy Process) and DEA(Data Envelopment Analysis) are used for weighting of qualitative performance measures and solving multiple-objective layout problem, respectively.

• 한국기계가공학회지
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• 제11권6호
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• pp.107-114
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• 2012

Fracture of brittle material due to dynamic load such a particle impact has been reported by many researchers as the fracture behavior by variation of stress for a short minute. Especially, the brittle material, such a ceramic, applied to the structural component of machine, is considered as the important project. In order to evaluate the improvement of impact resistance, the particle impact test for the $Al_2O_3-TiO_2$ coated glass is practiced. And then, the damage variation according to the impact energy of steel ball was evaluated. There was a large improvement by the ceramic coating on the surface of a glass substrate. The damage volume was especially imported to evaluate damage behavior in quantity. These data were plotted on logarithmic coordinate and experimental equations were induced by data analysis based on test results. And the variation of critical energy for crack initiation was analyzed with critical impact energy when each crack occurs.

• 한국시뮬레이션학회논문지
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• 제20권3호
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• pp.49-58
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• 2011

설비나 작업자에 대한 부하효율은 제조공장에서 생산용량계획을 수립하는데 중요한 정보다. 즉 공장에서 신제품을 개발하거나, 생산량을 증가시킬 경우, 새로운 투자계획을 수립할 경우에도 항상 설비나 작업자에 대한 부하효율을 검토한다. 이러한 부하효율을 추정하기 위해서 다양한 측정방법이 사용된다. 본 본문에서는 설문조사, 순간관측법, 동영상 촬영을 이용한 미세동작연구방법, ERP시스템에서 자료를 취득하는 방법, 시뮬레이션방법 등 다양한 측정방법의 정확성에 대해 실제 사례를 이용해 비교분석하였다. 본 사례연구는 리드프레임이나 패키징용 부품을 생산하는 국내 반도체부품 생산공장을 대상으로 수행하였다.