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입자경과 분쇄소비동력의 고찰에 의한 교반볼밀 분쇄특성의 정량적 연구
최희규,왕림,Choi, Hee-Kyu,Wang, Lin 한국재료학회 2007 한국재료학회지 Vol.17 No.10
A series of wet grinding experiments have been carried out using a stirred ball mill to systematically investigate consideration of grinding characteristics. The particle size distribution and median diameter of the grinding consumption power for a given grinding time were considered. Also, the effect of grinding aids on particle size and grinding consumption energy defined as the summation of grinding power was investigated. The grinding aids had influence on the smaller products size and decrease grinding consumption energy because the function of grinding aids were to be attribute to the prevention of agglomeration and ball and grinding chamber wall coating of sample powder. The grinding process seemed to be controlled by the force of agglomeration of the ground products. It was demonstrated that the particle size and grinding consumption energy could be more decreased by the addition of grinding aids.
분체공학 , 유동층 , 고분자 , 재료 ( 무기 , 유기 ) : 매체교반형 미분쇄기에 의한 무기분말의 초미분쇄 기구에 관한 연구
최희규(Hee Kyu Choi),최우식(Woo Sik Choi) 한국화학공학회 2002 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.40 No.4
Recently in various industrial processes, the need for fine particles especially submicron particles has been increased in preparation field of raw powders such as fine ceramics and high technical products. The grinding by a stirred ball mill to submicron range has been achieved commercially in many cases. A series of grinding experiments using a vertical stirred grinding media mill and inorganic powders such as calcite, pyrophyllite and talc as test samples were carried out to clarify the grinding mechanism of the stirred grinding media mill. The effect of experimental conditions such rotation speed of stirrer, ball filling ratio, ball diameter and slurry concentration on the power inputted in the stirred media mill were measured and the quantitative relationship between them was proposed with multiple regression analysis. The relationship between the experimental factors and the comminution consumption power could also be regressed as a power-law and effect of grinding aids on particle size distribution and on grinding efficiency defined as the increase of specific surface area per the specific grinding consumed energy was investigated. In this study it can be concluded that the grinding energy efficiency using grinding aids was improved about 13.1% than no aids experiment. And the effect of grinding aids on grinding rate constant K was investigated. Also the relationship between grinding rate constant K and experimental conditions including the effect of grinding aids was examined and it is confirm that the grinding rate can be improved in the degree of the maximum of 25.6% compared with without grinding aids.
한국 고유 담수어종 참갈겨니(Zacco koreanus) 개체군의 계통지리학 및 집단유전학 연구
김유림,장지은,최희규,이혁제,Kim, Yu Rim,Jang, Ji Eun,Choi, Hee-kyu,Lee, Hyuk Je 한국환경생물학회 2020 환경생물 : 환경생물학회지 Vol.38 No.4
본 연구는 동해유입하천(강릉 연곡천, 양양 남대천), 한강수계(섬강, 속사천), 낙동강수계(길안천)에 서식하는 참갈겨니(Zacco koreanus) 개체군을 대상으로 채집된 110개체로부터 미토콘드리아 DNA COI 유전자(mitochondrial DNA cytochrome oxidase I)를 분자마커로 이용하여 계통지리학적 분석을 수행하고, 추가적으로 강릉 연곡천 상·중·하류 개체군을 대상으로 집단유전학적 분석을 수행하였다. 계통지리학 분석 결과, 동해유입하천과 한강수계의 참갈겨니 개체군은 동일한 단일계통을 나타내었고, 낙동강수계의 개체군은 상이한 계통으로 분기됨을 나타내었으며, 다른 수계 계통과의 유전적 거리 수치 범위가 평균 4.0%(3.7~4.2%)로서 동일종 이상 수준을 보여 잠재종 가능성을 시사하였다. 참갈겨니가 서식하는 수계에 따른 형태학적 차이는 연구된 바 있으나 DNA 염기서열의 변이를 이용한 분자유전학적 연구는 부족한 실정이므로 본 연구 결과는 향후 낙동강수계 참갈겨니 개체군의 계통분류학적 연구에 기초자료로 활용될 수 있을 것으로 판단된다. 추후 집단유전체학 및 생태학적 분석을 통하여 관찰된 낙동강수계 계통이 다른 종, 잠재종 혹은 단순히 큰 수준의 종내 변이를 나타내는지에 대한 추가적인 연구가 필요하다. 강릉 연곡천 상·중·하류에 서식하는 개체군의 집단유전학 분석을 통해 중류의 개체군이 상대적으로 높은 다양성을 나타냈으며 상·중·하류 개체군 간의 유전적 차이는 나타나지 않았다. 이는 상·중·하류 개체군 간 유전자 확산이 원활하게 이루어지고 있음을 의미하며 하천의 개체군 간 연결성을 판단할 수 있는 지표로 활용될 수 있다. 하지만 생태학적 시간 스케일의 연구에 더 적합한 분자마커를 이용한 추후 연구가 필요할 것으로 사료된다. We conducted a phylogeographic analysis of Korean endemic Zacco koreanus populations inhabiting the East-flowing river (Gangneung Yeongokcheon; GY, Yangyang Namdaecheon; YN), the Han River (Seomgang; SG, Soksacheon; SS), and the Nakdong River(Gilancheon; GA) using the mitochondrial DNA cytochrome oxidase I (COI) gene (619 bp). Population genetic analysis was further performed to assess the population connectivity for the GY river where there is a large number of human-made artificial weirs with several fishways. The phylogeographic analysis revealed that while the populations of the East-flowing river and those of the Han River formed a monophyletic lineage, the Nakdong River individuals represented a distinct lineage with 3.7-4.2% (mean=4.0%) genetic distance from the other lineages. The population genetic analysis of the GY showed that a mid-stream population harbored relatively higher mitochondrial diversity relative to up- and down-stream populations, and there was no genetic differentiation between these three populations. The latter findings might suggest high genetic connectivity between the populations via genetic flow along the fishways. However, an analysis using faster-evolving genetic markers, such as microsatellites, is needed to confirm the findings of high population connectivity. Our study suggests the possibility of the presence of cryptic species in Z. koreanus in the Nakdong River basin. However, further study with more individual samples as well as additional markers or even more advanced genomic tools is required to test our hypothesis. Ecological or phenotypic analyses should be conducted to test whether the observed Nakdong River lineage represents a different or cryptic species, or simply hidden, but excessive, intraspecific diversity.
임현서(Hyun-Seo Im),최희규(Hee-Kyu Choi),이창호(Chang-Ho Lee),이초재(Cho-Jae Lee),유지환(Ji-Hwan Yoo),김성빈(Sung-Bin Kim),김희중(Hee-Joong Kim),안달(Dal Ahn) 한국정보기술학회 2012 Proceedings of KIIT Conference Vol.2012 No.11
본 논문에서는 상용화가 가능한 블루투스 기능을 가진 스피커를 구현하였다. 이 장치는 신호를 쉽게 공급할 수 있음으로써 편리함과 실용성을 갖출 뿐만 아니라 무선이므로 선의 구조를 확인 할 필요가 없다. 또한, 원하는 신호의 출력을 얻기 위해 15W급의 전력증폭기를 제작하였고, 배터리 용량에 따른 잡음개선 효과도 분석하였다. 이를 통해, 효율적으로 신호를 보낼 수 있게 입력신호에 블루투스 모듈을 삽입하여 무선 스피커를 구현하였다. In this paper, We implemented with commercially available bluetooth loudspeaker. As easily can supply signals, It has not only convenience and practicality, but also no need to check composition of line. We made 15W high power amplifier in order to get output of desired signal and analyzed the noise level according to battery capacity Through this, we made wireless loud speaker that has bluetooth module to efficiently send a signal.