광양줄똥풍뎅이를 기반한 한반도에서의 흰개미종속인 줄똥풍뎅이족(딱정벌레목: 풍뎅이과)의 새로운 발견

최익제,김상수,이봉우,임종옥,Choi, Ik Je,Kim, Sang Su,Lee, Bong Woo,Lim, Jongok Korean Society of Applied Entomology 2015 한국응용곤충학회지 Vol.54 No.4

Rhyparus azumai azumai Nakane, 1956을 기반으로 Rhyparini족을 국내에서 처음으로 보고한다. 본 종의 형태학적 재기재, 수컷 생식기를 포함한 진단학적 형질 사진, 그리고 한국산 똥풍뎅이아과의 족 분류 검색표를 제공한다. A termitophilous tribe, Rhyparini Schmidt, 1910 of the subfamily Aphodiinae Leach, 1815 (Coleoptera: Scarabaeidae) is newly recorded from Korea for the first time, based on Rhyparus azumai azumai Nakane, 1956. A redescription, illustrations of diagnostic characteristics including male genitalia, and a key to Korean tribe of the subfamily are provided.

전기전도도 시험방법을 활용한 산업부산물 포졸란재료의 반응성 평가

최익제,김지현,이수용,Choi, Ik-Je,Kim, Ji-Hyun,Lee, Soo-Yong 한국건축시공학회 2016 한국건축시공학회지 Vol.15 No.4

본 연구에서는 전기전도도 시험방법을 이용하여 다양한 산업부산물재료의 포졸란 반응성을 평가할 수 있는 대안을 제안하고자 하였다. 실험에 사용된 재료는 일반적으로 포졸란 재료로 활용되고 있는 산업부산물 플라이애시(class F, C) 2종, 실리카퓸(densified, undensified) 2종, 메타카올린과 포졸란 반응성이 정량적으로 증명되지 않은 산업부산물인 벤토나이트, 그라스울, 세라믹을 활용하여 포졸란 반응성을 측정 하였다. 각 재료가 $40^{\circ}C$ 포화수산화칼슘 수용액에 침지된 이후의 전기전도도의 변화를 관찰하였으며, $450{\sim}500^{\circ}C$에서 관찰된 수산화칼슘의 분해량을 통해 포졸란 반응성을 교차 검증하였다. 28일 압축강도 또한 포졸란 반응에 의한 역학적 성능의 개선여부를 검증하기 위해 활용되었다. 실험결과에 따르면, 전기전도도 최대값과 4시간후의 전기전도도의 차이를 활용하여 포졸란 반응성을 평가하는 것이 적절하다고 나타났다. 이러한 방법을 활용할 경우 수산화칼슘 함유량에 근거한 포졸란 반응성 평가와 매우 유사한 결과를 얻을 수 있었으며, 28일 압축강도 측정을 통해 얻은 결과와도 큰 차이를 보이지 않아, 전기전도도 시험법이 포졸란 반응성이 증명되지 않은 재료의 포졸란 반응성평가에도 충분히 활용될 수 있는 것으로 나타났다. In this work, pozzolanic activities of various waste materials were compared with those of well-known by-product pozzolanic materials. Undensified and densified silica fume, ASTM class F and class C fly ash, and metakaolin were chosen as well-known pozzolanic materials, and bentonite powder, ceramic powder obtained from wash basin, and waste glass wool, which can possibly possess pozzolanic property, were chosen for comparison. Drop in electrical conductivity at $40^{\circ}C$ saturated lime solution was measured for each materials. The amount of Ca(OH)2 decomposed from cement paste at $450{\sim}500^{\circ}C$ was also measured to evaluate pozzolanic activity. The 28 day compressive strength were used to observe the mechanical property enhanced by incorporation of various waste materials. According to the experimental results, using "difference between maximum conductivity value and conductivity value at 4 hour" was found to be a reasonable approach to determine pozzolanic activity of a material. Pozzolanic activity measured using electrical conductivity correlates very well with that measured using the amount of Ca(OH)2 remained in the cement paste. Relatively good agreement was also found with electrical conductivity and 28 day compressive strength. It was found that electrical conductivity measurement can be used to evaluate pozzolanic activity of unknown materials.

자력 선별된 바텀애쉬를 활용한 모르터의 물성 평가

최익제 ( Ik Je Choi ),장보길 ( Bo Kil Jang ),김지현 ( Ji Hyun Kim ),정철우 ( Chul Woo Chung ),이재용 ( Jae Yong Lee ) 한국건축시공학회 2015 한국건축시공학회 학술발표대회 논문집 Vol.15 No.2

Significant amount of bottom ash has been produced in the power plant located at southeast region of Korea, but those were abandoned in the pond site without any treatment. In these days, there is a strong move to enforce environmental regulations to protect surrounding nature, a lot of pressure is given to the power plant industry to remove hazardous chemicals from their waste material before landfill or site storage. The overall objective of this research is to separate hazardous chemicals from the bottom ash, and use it safely as sustainable construction material. In this specific study, magnetic separation of bottom ash was applied, and used as a fine aggregates to make mortar specimens. According to the results, it was found that the use of bottom ash decreased 28-day compressive strength. However, using non-magnetic bottom ash provides best results in terms of thermal conductivity, showing strong possibility to be used as heat insulating material.

다양한 산업부산물들의 포졸란 반응성 비교분석

최익제 ( Ik Je Choi ),김지현 ( Ji Hyun Kim ),정철우 ( Chul Woo Chung ),이수용 ( Soo Yong Lee ) 한국건축시공학회 2016 한국건축시공학회 학술발표대회 논문집 Vol.16 No.1

In this work, pozzolanic activities of various waste materials were compared with those of well-known pozzolanic materials. Uncondensed and densified silica fume, two ASTM class F fly ashes with different calcium contents, and bentonite powder, ceramic powder obtained from wash basin, and waste glass wool, which can possibly possess pozzolanic property were chosen for comparison. Drop in electrical conductivity at 40ºC saturated lime solution was measured for each materials. The amount of Ca(OH)2 decomposed from cement paste at 450~500ºC was also measured used to evaluate pozzolanic activity. The 28 day compressive strength were used to observe the mechanical property enhanced by various waste materials.

文化的 葛藤에 대한 初期 韓國 改新敎의 認識과 對應

최익제(Choi Ik-je) 역사문화학회 2005 지방사와 지방문화 Vol.8 No.2

In the early days of missionary work, the process of indigenization for the Protestantism was overcoming difficulties of cultural conflict. Specifically, The strong resistance of Confucianism and Shamanism are to be expected from the Andong province. Therefore, the strategy of indigenization was very unique and special in this area. In this viewpoint, I examined the recognition and confrontation of the early Korean Christian Church against cultural conflict. In early mission work, the most symbolic example of cultural conflict which occurred in the Andong province is ‘the Seomchon Church suffered incident’. According to this event, we know that the early church overcame the resistance of Confucianism through religious faith. The conflict of Confucianism was a formal problem, but aside from worshiping God, the Christian religion did not pose a doctrinal(creedal) problem. This was in part due to Christianity’s differentiated approach to traditional culture and their missionaries’ positive approach which made a great contribution to lessen the conflict. Through the process of solving these problems, we can see the relationship between the Japanese and missionaries. We can see the resistance of ‘Shamanism’ to church culture in the missionary circuit of Kim Su-man. It is clear that Korean Christianity has converted Shamanism’s religious ethos to the faith. In the beginning korean Christianity just solved cultural conflict as a daily problems. The counter-strategy of the cultural resistance was suggested by Organizational Church. The first thing that an attempt of Organizational Church was the Chiri(治理) and Kwonjing(勸懲). it can be the means of establishing the church’s identity and strengthening organizational health by the tension in the relationships of the church organization. Hard and stern, Chri and Kwonjing, which was carried into effect positively showed a risk of identity crisis in the early days of the church. The success and failure of indigenization depends on the ethical level of the church. Secondly, It relates to the activity of the church oriented education. It can proliferate church culture and reproduce the kernal of that culture. With Biblical Revival (査經會: Bible study, holly spirit congregation) and Sunday School centered on educational activity it had potential to replace public education in Andong province. It offered a good educational function and modernization to the that outcasts of society. Through this process, church education tried to absorb their cultural shock completely. For example, Gaeshin Christian Private School which attached to the Bibong Church included in its teaching modern science, the Bible, and Confucianism scripture. They entrusted non-christian confucian scholars with school management. In summary, Cultural capacity of the regional churches, which is faithful to Nevius Method, helped to percolate church culture into the mass of anti-christian; that is to say, they did not confine church culture to the chapel.

그래핀을 혼입한 시멘트페이스트의 기초물성 평가

최익제 ( Choi Ik-je ),김지현 ( Kim Ji-hyun ),정철우 ( Chung Chul-woo ) 한국구조물진단유지관리공학회 2020 한국구조물진단유지관리공학회 학술발표대회 논문집 Vol.24 No.1

그래핀은 우수한 역학적 특성, 전기전도성, 열전도성 등으로 다양한 산업에 이용되고 있다. 최근 건설산업에서는 건물들이 초고층화 되면서 UHPC의 사용이 빈번하며, UHPC 특성상 자기수축 등의 체적 안정성의 문제에 노출 되어 있다. 이를 해결하기 위해 다양한 나노재료를 혼입한 UHPC가 연구되고 있다. 시멘트 복합체에 그래핀등을 혼입하기 위해서는 용액내 분산, 시멘트 복합체내의 분산이 중요시 되고 있다. 그래핀의 혼입율, 분산방법에 따라 강도 값이 다르게 나왔으며, 굳지않은 시멘트 페이스트의 유변학적 특성은 강도경향과 다르게 나타나고 있다. 이는 그래핀이 시멘트 페이스트 내에서 분산이 제대로 되지 않은 것으로 판단된다.

그래핀을 혼입한 콘크리트의 물리적 성능 평가

최익제 ( Choi Ik-je ),김지현 ( Kim Ji-hyun ),김무준 ( Kim Moo-joon ),김상호 ( Kim Sang-ho ),이정훈 ( Lee Jounghoon ),정철우 ( Chung Chul-woo ) 한국구조물진단유지관리공학회 2019 한국구조물진단유지관리공학회 학술발표대회 논문집 Vol.23 No.2

건물의 규모가 대규모화 되면서 고성능 콘크리트의 필요성이 커지고 있다. 하지만 고성능 콘크리트의 문제점으로 시멘트 수화물 생성시 부피 안정성 문제를 일으킨다고 알려지면서 시멘트 기반재료와 나노재료의 혼합기술에 관한 연구에 관심이 증대 되고 있다. 본 연구에서는 나노재료 중에서도 그래핀을 콘크리트에 혼입하여 콘크리트의 역학적 성능 및 내구성 증대와 함께 다양한 기능성이 발현되는지 알아보고자 한다.

전기전도도 시험방법을 활용한 산업부산물 포졸란재료의 반응성 평가

최익제 ( Choi Ik-je ),김지현 ( Kim Ji-hyun ),이수용 ( Lee Soo-yong ) 한국건축시공학회 2016 한국건축시공학회지 Vol.16 No.5

In this work, pozzolanic activities of various waste materials were compared with those of well-known by-product pozzolanic materials. Undensified and densified silica fume, ASTM class F and class C fly ash, and metakaolin were chosen as well-known pozzolanic materials, and bentonite powder, ceramic powder obtained from wash basin, and waste glass wool, which can possibly possess pozzolanic property, were chosen for comparison. Drop in electrical conductivity at 40oC saturated lime solution was measured for each materials. The amount of Ca(OH)2 decomposed from cement paste at 450~500oC was also measured to evaluate pozzolanic activity. The 28 day compressive strength were used to observe the mechanical property enhanced by incorporation of various waste materials. According to the experimental results, using “difference between maximum conductivity value and conductivity value at 4 hour” was found to be a reasonable approach to determine pozzolanic activity of a material. Pozzolanic activity measured using electrical conductivity correlates very well with that measured using the amount of Ca(OH)2 remained in the cement paste. Relatively good agreement was also found with electrical conductivity and 28 day compressive strength. It was found that electrical conductivity measurement can be used to evaluate pozzolanic activity of unknown materials.

나노재료를 혼입한 시멘트 페이스트의 기초 물성 비교

최익제(Choi, Ik Je),김지현(Kim, Ji Hyun),정철우(Chung, Chul-Woo) 한국콘크리트학회 2020 한국콘크리트학회 학술대회 논문집 Vol.32 No.1

나노재료를 혼입한 시멘트 페이스트의 역학적 특성

최익제 ( Choi Ik-je ),김지현 ( Kim Ji-hyun ),정철우 ( Chung Chul-woo ) 한국건축시공학회 2020 한국건축시공학회 학술발표대회 논문집 Vol.20 No.1

Recently, as the use of high-performance concrete has become common, various problems related to high-performance concrete have become an issue. Among them, self-shrinkage of cement paste due to low water cement ratio is known to cause problems in the volume stability of concrete. To improve this, studies related to the mixing technology of cement-based materials and nano materials have been actively conducted. Looking at the results of prior research related to nano material mixing technology, generally, research results have been reported in which nano materials are incorporated into cement-based materials to improve material properties1). Among them, it was shown that the mechanical performance and various types of functionality of the cement composite are expressed. Among nano materials, carbon nanotubes (hereinafter referred to as CNTs) and graphenes are used in a mixture with cement-based materials. Accordingly, this study intends to compare the mechanical properties by incorporating various CNTs and graphene into cement paste.