슬러리법에 의한 탄소섬유보강 시멘트복합체의 제조에서 보강섬유와 계면결착제와의 상관특성

최응규,Choi, Eung-Kyoo 한국건축시공학회 2002 한국건축시공학회지 Vol.2 No.3

The objective of the study is to examine the characteristic correlations between reinforcing carbon fiber and interfacial adhesion agent since the interfacial adhesion strength between reinforcing carbon fiber and matrices is believed to be an essential element influencing the physical properties in carbon fiber reinforced cement composite using slurry method. The integrity of interfacial adhesion between reinforcing fiber and cement not only affects the quality of fiber reinforced cement composite but also influences to a large degree the physical properties of the cement composite when producing carbon fiber reinforced cement composite using slurry method. Having analyzed the physical properties 1.e., water content, tensile strength, flexural strength and flexural toughness of carbon fiber reinforced cement composite specimens, C-PAM(cation polyacrylamide) was determined to be an optimum interfacial adhesion agent. The study has also demonstrated that interfacial adhesion strength varies largely on the content and type of the reinforcing fiber. Judging from magnified view of the tensile shear cross-section using VMS(video microscope system), interfacial adhesion strength between reinforcing fiber and matrices is affected by the type of interfacial adhesion agent. According to the result of the experiments, C-PAM was determined to be an ideal interfacial adhesion agent when using carbon fiber in producing carbon fiber reinforced cement composite with the optimum content of carbon fiber being established.

무기충전재 함량에 따른 PVA섬유강화 시멘트복합체의 계면결착특성 및 물성고찰

최응규(Choi Eung-Kyoo) 대한건축학회 2003 大韓建築學會論文集 : 構造系 Vol.19 No.8

The aim of the study is to suggest an optimal inorganic filler and its contents applicable to PVA fiber reinforced cement matrix by means of quantifying the degree of interfacial adhesion between a selected range of inorganic filler materials and PVA fibers followed by analyzing physical and mechanical properties of PVA fiber reinforced cement composite in relation to the contents of inorganic filler. Based on the result of analysis on interfacial adhesion between inorganic filler and PVA fiber materials, kaolin, fly ash andmica have proved to be excellent filler materials for cement matriceshaving superior adhesion performance with PVA fibers.Compactness of cement matrix is influenced by chemical components and their content of the respective filler material being used.In addition physical properties are heavily affected by type of filler materials and its configuration. Observing the failure plane ofPVA fiber-reinforced cement composite mixed with one of the optimal filler materials, mica, the specimens have exhibited highdegree of compactness with little PVA fibers pulled out within the cement matrix. The key elements in producing fiber reinforced cement matrix using a range of filler materials are: (1) Selection of filler material chemically compatible with reinforcing fibers (2) Maintaining maximum adhesion between reinforcing fiber and filler material (3) Use of optimal content of filler materials. The experimental study has determined that when PVA fiber is used in cement matrix, mica proved to be the most suitable filler material and the range of content is from 20% to 25%.

시금장 발효기간에 따른 품질 변화

최응규(Ung-Kyu Choi),권오준(O-Jun Kwon),손동화(Dong-Hwa Son),차원섭(Won-Seop Cha),조영제(Young-Je Cho),이석일(Suk-Il Lee),양성호(Sung-Ho Yang),정영건(Yung-Gun Chung) 한국식품과학회 2001 한국식품과학회지 Vol.33 No.1

연구소원 연구논문초록 ( 재록 , 1996 ~ 1997 년 ) : 반응표면 분석에 의한 Bacillus subtilis DC-2 의 색소생성 및 그 생성물의 항산화성에 대한 최적조건

최응규(Ung Kyu Choi),지원대(Won Dae Ji),정현채(Hyun Chae Chung),최동환(Dong Hwan Choi),정영건(Yung Gun Chung) 영남대학교 장류연구소 1998 영남대학교 장류연구소 연구업적집 Vol.1 No.-

싹튼 콩으로 제조한 메주의 발효기간에 따른 품질변화

최응규(Ung-Kyu Choi),김미향(Mi-Hyang Kim),이난희(Nan Hee Lee),정연신(Yeon-Shin Jeong),황영현(Young-Hyun Hwang) 한국식품과학회 2007 한국식품과학회지 Vol.39 No.3

본 연구에서는 24시간 동안 싹튼 콩을 원료로 하여 콩알 메주를 제조한 후 발효기간에 따른 각종 품질의 변화를 조사하였다. 발효 전 기간 동안 pH는 6.3-6.5로 큰 변화가 없는 것으로 조사되었다. 증자 직후의 아미노태 질소함량은 15.5 ㎎%였으며, 발효가 진행됨에 따라 급격히 증가하여 발효 48시간째에는 312.9㎎%를 나타내었다. 발효기간별 미생물의 변화를 확인한 결과 곰팡이의 수가 높게 나타난 반면 호기성 세균과 효모의 수는 낮게 나타났는데 이는 메주의 제조 시 Aspergillus oryzae를 접종하였기 때문인 것으로 판단된다. 발효가 진행됨에 따라 유기산 함량은 점차 높아져 발효 48시간째에는 1,067.3 ㎎%가 검출되었으며 함량별로는 발효전 기간에 걸처 citric acid가 가장 많이 검출되었다. 유리아미노산 함량은 발효가 진행됨에 따라 함량이 급격히 높아져 발효 48시간째에는 2,513.5 ㎎%로 발효 전에 비해 5.7배 가량 많이 검출되었다. 함량별로 보면 glutamic acid가 가장 많았으며, asparticacid, lysine, leucine 및 proline의 순으로 많이 검출되었다. glutamic acid의 총아미노산에 대한 비율은 발효가 진행됨에 따라 점차 증가하여 발효 48시간째에는 21.2%로 나타났다. 총 Isoflavone의 함량은 발효초기에 123.9㎎%로 약간 증가한 후 그 수준을 지속적으로 유지하는 것으로 나타났으며, 발효 전 기간 동안 genistein>daidzein>glycitein의 순으로 나타났다. This research was conducted to investigate the changes in quality characteristics of meju made with 24-hour germinated soybeans according to fermentation time. The study confirmed that the amino nitrogen content immediately after soaking was 15.5 ㎎%, and the content rapidly increased in the beginning of the germination process and continued to increase to 312.9 ㎎% by 48 hours of fermentation. The number of fungi in the whole soybean meju made with 24-hour germinated soybeans was higher than the numbers of bacteria and yeast since the Aspergillus oryzae was inoculated artificially. The content of organic acids, in which the amount of citric acid was highest followed by tartaric acid and malic acid, increased with the fermentation process. The level of free amino acids in the whole soybean meju made from the 24-hour germinated soybeans increased rapidly with fermentation. The free amino acid content after 48 hours of fermentation (2,513.5 ㎎%) was 5.7 times higher than the content of the soaked germinated soybeans. The content of glutamic acid was highest followed by aspartic acid, lysine, leucine, and proline. The ratio of glutamic acid to the total free amino acids at 48 hours fermentation was 21.2% for the whole soybean meju. It was confirmed that the total isoflavone content, in which the content of genistein was highest followed by daidzein and glycitein, increased at the beginning of the fermentation process, but did not change thereafter.

오이 과실 표면의 과분 발생 특성

최응규(Eung Kyu Choi),김병수(Byung-Soo Kim),황운순(Un Sun Hwang),도한우(Han Woo Do),서동환(Dong Hwan Suh) 한국원예학회 2013 원예과학기술지 Vol.31 No.2

오이는 품종에 따라 과실표면에 과분(果紛) 소위 ‘bloom’이 발생하는데 이는 외관상 과실의 품질을 저하시키는 요인이 된다. 본 시험은 주관 종자회사에서 수집하여 육성하여 오던 bloomless 대목용 호박재료를 이용하여 ‘bloomless 대목’을 개발하고 앞으로 새로운 대목육성에 필요한 기초자료를 얻고자 하였다. Bloomless 오이의 표면은 분비모(glandular trichome, 分泌毛)의 낭상세포(bladder cell)가 형성되어 존재하고 있음을 관찰할 수 있었으며, 낭상세포 외의 과실표면은 상각피[epicuticular waxes(EW)] 층이 형성되어 있는 것을 관찰할 수 있었다. 또한 오이의 EW 형태는 둥근 모양의 결정체가 겹쳐진 형태이었으며, 그물 모양의 능선과 능선 안쪽에 고르게 분포하는 것으로 관찰되었다. 이와 다르게 bloom 현상이 나타나는 오이의 과실표면은 낭상세포의 형태가 크게 부풀어 있거나 터져 있었으며, 또한 손상된 낭상세포 주변으로 bloomless 오이에서 관찰되지 않았던 많은 입자들을 볼 수 있었다. Bloom과 bloomless 과실표면의 색도를 조사한 결과 bloom이 발생한 과실과 발생하지 않은 과실의 색도 ‘a’와 ‘b’ 값의 유의성은 없었고, ‘L’ 값은 bloom이 발생한 과실에서 높았다. 오이 과실의 규소 함량은 bloomless 대목에 접목한 오이 과실이 일반대목에 접목한 것에 비하여 현저히 낮았다. A white powder-like substance, so called ‘bloom’, is formed on the surface of fruits of many varieties of cucumber. Although it is a natural phenomenon, bloomed fruits are accepted lower in quality compared to bloomless fruits by consumers. The experiments were conducted to obtain basic informations for breeding rootstocks, and to develop promising bloomless rootstocks from basic source materials collected and selected by seed company. The surfaces of bloomless fruits were appeared on the bladder cell of glandular trichome and the epicuticular waxes. Those of bloom fruits appeared with an injured bladder cell and many particles, which were not seen on those of bloomless fruits. The chromaticity was investigated on the surface of the bloom and the bloomless fruits. The ‘a’ and ‘b’ value of the bloom and the bloomless fruits did not show any significant difference. The ‘L’ value was significantly different and that of bloom fruits was higher than that of bloomless fruits. Fruit Si content was conspicuously lower in the fruits of cucumber plants grafted on the bloomless rootstock than in the fruits of those grafted on general bloom rootstocks.

유기질섬유 계면처리에 따른 유기섬유강화 시멘트복합체의 계면구조특성 및 물성고찰

최응규(Choi Eung-Kyoo) 대한건축학회 2003 大韓建築學會論文集 : 構造系 Vol.19 No.8

The aim of the study is to analyze physical and mechanical properties of cement composite specimens by way of adding varying contents of a selected range of Polyacrylamides(PAMs) as interfacial coupling agent for organic fibers. In line with the aim of the study, mode of failure has also been carefully examined. Based on the experiment, the study attempts to suggest a characteristic of interfacial structure matrix and physical properties of organic fiber-reinforced cement composite. In the experiment, N-PAM(Nonion), C-PAM(Cation) and A-PAM(Anion) were used as interfacial coupling agent for organic fibers such as PVA and acrylics. The experiment has demonstrated A-PAM for PVA fibers and C-PAM for acrylic fibers to be an optimum interfacial coupling agent for the respective organic fibers in terms of both interfacial adhesion and physical properties. When an inappropriate interfacial treatment agent was used, a number of organic fibers were found to have been pulled out and the matrices were found to be loose. It is evident from the experiment that there is an optimal PAM as interface treatment agent for respective organic fibers, producing high degree of compactness of the matrix as well as excellent physical properties including interfacial adhesion. The experiment has demonstrated that when PVA fibers are treated with A-PAM and acrylic fibers with C-PAM, PVA fibers proved to be superior to acrylic fibers in terms of adhesion to cement matrix as well as in terms of physical and mechanical properties.

석면대체 아크릴섬유강화 시멘트복합체에서 각 구성소재의 최적조건 및 물성연구

최응규(Choi Eung-kyoo) 대한건축학회 2003 大韓建築學會論文集 : 構造系 Vol.19 No.7

The objective of the study is to analyze the optimum condition and properties of the components necessary for producing acrylic fiber-reinforced cement composite using acrylic fiber, usage of which is now common in most developed countries, as a substitute for asbestos. When acrylic fiber is used as reinforcing fiber in a cement composite, C-PAM(Cation Polyacrylamide) proved to be an optimum interfacial coupling agent in terms of adhesion between acrylic fiber and cement. Excellent degree of internal compactness of the cement composite can be achieved in respect of water content and water absorption by adding adequate amount of acrylic fiber and C-PAM. In respect of tensile and flexural properties, the content of acrylic fiber has significant effect not only on the interfacial adhesion and compactness of the matrices also on the properties of the cement composite. Having examined the tensile failure planes of acrylic fiber-reinforced cement composite, the content of reinforcing fiber determines the mode of failure either pullout or shear of the fibers in the matrix. Optimization of the fiber content is therefore crucially important in the mixture of cement composites. The study has demonstrated that acrylic fiber-reinforced cement composite with excellent interfacial adhesion can be achieved by combining the three key components - acrylic fiber, talc and recycled sulfite pulp, mixed with C-PAM as interfacial coupling agent - with their optimum content being 2.0∼2.5%, 25% and 3.0%, respectively.

무기섬유보강 시멘트복합체에서 계면결착제가 무기섬유계면에 미치는 영향

최응규(Choi Eung-kyoo),고성석(Go Seong-seok),김선국(Kim sun-kuk) 대한건축학회 2003 大韓建築學會論文集 : 構造系 Vol.19 No.4

The objective of the study is to examine the characteristic correlations between reinforcing inorganic fiber and interfacial adhesion agent since the interfacial adhesion strength between reinforcing inorganic fiber and matrices is believed to be an essential element influencing the physical properties in inorganic fiber reinforced cement composite using slurry method. The integrity of interfacial adhesion between reinforcing fiber and cement not only affects the quality of fiber reinforced cement composite but also influences to a large degree the physical properties of the cement composite when producing inorganic fiber reinforced cement composite using slurry method. IIaving analyzed the physical properties i.e., water content, tensile strength, flexural strength and flexural toughness of inorganic fiber reinforced cement composite specimens, C-PAM(cation polyacrylamide) was determined to be an optimum interfacial adhesion agent. The study has also demonstrated that interfacial adhesion strength varies large]y on the content and type of the reinforcing fiber. Judging from magnified view of the tensile shear cross-section using VMS (video microscope system), interfacial adhesion strength between reinforcing fiber and matrices is affected by the type of interfacial adhesion agent. According to the result of the experiments, C-PAM was determined to be an ideal interfacial adhesion agent when using carbon fiber in producing inorganic fiber reinforced cement composite with the optimum content of carbon fiber being estabJished.

보강섬유와 시멘트와의 매트릭스(Matrix) 구조에서 계면가교제가 계면결착에 미치는 특성

최응규(Choi Eung-kyoo) 대한건축학회 2003 大韓建築學會論文集 : 構造系 Vol.19 No.7

It is necessary to reinforce the interfacial adhesion between components in fiber reinforced cement composite either by surface treatment thereby producing interfacial attraction or by reinforce the interfacial adhesion between organic and inorganic materials by means of coupling agent. The objective of the study is to propose a practical approach in selecting a suitable interfacial coupling agent for an assorted reinforcing fiber and cement compounds and to determine the most appropriate coupling agent for a particular combination. The experiment analyzed the integrity of the interfacial adhesion by means of VMS(video microscope system) as well as by measurement of interfacial adhesion, demonstrating polyacrylamide, a polymeric coupling agent, being the most effective coupling agent for the purpose of reinforcing the interfacial adhesion between reinforcing fiber and cement. There are three different kinds of PAM depending on the ionization; N-PAM, A-PAM and C-PAM, each reinforcing fiber material having its own optimum PAM. The experiment has demonstrated that N-PAM was least effective for all the reinforcing fibers used in the analysis. While A-PAM coupling agent was most effective in PVA fibers, C-PAM proved to be the most effective coupling agent in both acrylic and carbon fibers.