CFRP복합재료의 적층수와 드릴직경에 따른 가공 특성

정성택,박종남,조규재 한국공작기계학회 2003 한국공작기계학회 춘계학술대회논문집 Vol.2003 No.-

CFRP composite has a lot of merits such as mechanical characteristic, light weight, and thermal resistance. For these merits CFRP is applied to so many industrial area. In this paper, the relationship between the stack thickness and drill diameter is examined from the drilling experiment, which is the drilling of 16, 32, 48plies specimen with the φ8, φ10, φ12mm cemented carbide drill. The results are analyzed with consideration of cutting force, stack thickness and drill diameter.

CFRP복합재료의 적층수와 드릴직경에 관한 연구

정성택,박종남,조규재 한국공작기계학회 2003 한국생산제조학회지 Vol.12 No.6

CFRP composite has a lot of merits such as mechanical characteristic, light weight, and thermal resistance. For these merits CFRP is applied to so many industrial area. In order for the composite materials to be used in the air& structures or machine elements, accurate surfaces for bearing mounting or joints must be provided, which require precise machining. In this paper, the relationship between the stack thickness and drill diameter is examined from the drilling experiment, which is the drilling of 16, 32, 48plies specimen with the φ8, φ10, φ12mm cemented carbide drill. The results are analyzed with consideration of cutting force, stack thickness and drill diameter.

적층구성이 다른 복합재의 드릴 가공에 관한 연구

정성택,박종남,조규재,심재기 한국공작기계학회 2002 한국공작기계학회 추계학술대회논문집 Vol.2002 No.-

In recent days the more use of CFRP composite is in the airplane, automobile, and sport goods , etc., the more necessity of research on it in this engineering. In this research, the CFRP composite specimen are fabricated by 48 CFRP plies with 6 stacking sequences, and the specimens are drilled with 4 tools. The results are analyzed with consideration of cutting force, type of tools and fabrication condition. The specimens with each drilling conditions are also investigated with SEM. The optimal drilling conditions such as drill types and cutting force with respect to the fabricating condition are studied.

CFRP복합재료의 적층각에 따른 가공 특성

정성택,박종남,김선진,조규재 한국공작기계학회 2002 한국공작기계학회 춘계학술대회논문집 Vol.2002 No.-

In recent days the more use of CFRP composite is in the airplane, automobile, and sport goods, etc., the more necessity of research on it in this engineering. In this research, the CFRP composite specimen are fabricated by 48 CFRP plies with 8 orientation angles, and the specimens are drilled with 3 tools. The results are analyzed with consideration of cutting force, type of tools and fabrication condition. The specimens with each drilling conditions are also investigated with SEM. The optimal drilling conditions such as drill types and cutting force with respect to the fabricating condition are studied.

완전 고환성 여성화 증후군 1례

이원주,김택훈,권경익,김종인,조남규,박세출 啓明大學校 醫科大學 1993 계명의대학술지 Vol.12 No.2

저자들은 외형상 여성으로써 원발성 무월경과 양측 외음부 종양 촉지를 주소로 입원한 complete testicular feminization syncrome 1례를 경험하였기에 이를 문헌고찰과 함께 보고하는 바이다 The 46, XY individual with complete testicular feminization syndrome is a phenotypic female who is usually somewhat tall, has excellent breast development and presents to the gynecologist because of primary amenorrhea and an inguinal mass. In complete testicular feminization syndrome, axillary and pubic hair are sparse or absent and some degree of virilization such as clitorial hypertrophy, partial labioscrotal fusion and hirsutism doesn't occur at puberty. We report a case of complete testicular feminization syndrome with the brief review of literatures.

볼나사 지지 구조와 베어링 조합 배열에 관한 연구

홍성오,정성택,조규재 한국공작기계학회 2002 한국생산제조학회지 Vol.11 No.3

In order to achieve high precision machine tools, Performance enhancement of feed drive systems is required. One of the important technical issues is how to decrease thermal expansion of ball screw in proportion to the increase of machining speed. When measuring force of stretch of ball screw, since not only actual expansion and the value of bending have to be considered, it is impossible to define the exact value of expansion. In addition, support bearings of ball screw gain considerable force in axial direction. It also generates thermal expansion on the ball screw, and deteriorates the performances of the bearings. In conclusion, it is impossible to give the pretension enough to absorb all the elongation due to thermal expansion generated during machine is running. If give, bed column and saddle are all bent to change machine accuracy, and the support bearings of ball screw is damages.

Development of a Core Set of Korean Soybean Landraces [Glycine max(L.) Merr.]

Cho, Gyu-Taek,Yoon, Mun-Sup,Lee, Jeong-Ran,Baek, Hyung-Jin,Kang, Jung-Hoon,Kim, Tae-San,Paek, Nam-Chon The Korean Society of Crop Science 2008 Journal of crop science and biotechnology Vol.11 No.3

A total of 2,765 accessions were used as the initial set having both seed coat color and 100-seed weight data. As a result of molecular profiling using six SSR markers followed by stratification based on their usages, 335 accessions(12.1%) were selected by clustering based on UPGMA. Since 75 out of 335 accessions were mixed in phenotypic traits as a result of characterization, 260 accessions were finally set as a core set. This core set revealed nearly the same diversity compared with the other results on morphological traits of Korean soybean landraces. In total, 115 alleles(19.2 alleles per locus) were detected in the initial set and 79 alleles(13.2 alleles per locus) were detected in the core set. All 30 major alleles were present in the initial set and in the core set as well. In allele coverage, the core set was 71.4% of the initial set. These comparisons of number of alleles, gene diversity and coverage indicated that the core set represented the entire set well.

Genetic Diversity and Population Structure of Korean Soybean Landrace [Glycine max(L.) Merr.]

Cho, Gyu-Taek,Lee, Jeong-Ran,Moon, Jung-Kyung,Yoon, Mun-Sup,Baek, Hyung-Jin,Kang, Jung-Hoon,Kim, Tae-San,Paek, Nam-Chon The Korean Society of Crop Science 2008 Journal of crop science and biotechnology Vol.11 No.2

Two hundred and sixty Korean soybean landrace accessions were analyzed for polymorphism at 92 simple sequence repeat(SSR) loci. The 995 identified alleles served as raw data for estimating genetic diversity and population structure. The number of alleles at a locus ranged from three to 27 with a mean of 10.4 alleles per locus. $F_{ST}$ values estimated by analysis of molecular variance(AMOVA) using SSR data set were 0.018, 0.027, and 0.016 for usage, collection site and maturity groups, respectively, indicating little genetic differentiation. The model-based clustering analysis placed the accessions into three clusters(K=3) with 0.0503 of $F_{ST}$, indicating moderate genetic differentiation. Duncan's Multiple Range Test at K = 3 on the basis of 18 quantitative traits revealed that one cluster was mainly differentiated from the other two clusters by seed related traits and the other two clusters were differentiated from each other by biochemical traits. Genetic structure of Korean soybean landraces was differentiated by model-based clustering and supported by their phenotypic traits in part. This preliminary study could be the first step towards more efficient germplasm management and utilization of soybean landraces and helpful in association studies between genotypic and phenotypic traits in Korean soybean landraces.

Evaluation of Clubroot Resistance in Chinese Cabbage and Its Inheritance in the European Turnip Line 'IT033820', a New Genetic Resource

Cho, Kang Hee,Kim, Ki Taek,Park, Suhyung,Kim, Su,Do, Kyung Ran,Woo, Jong Gyu,Lee, Hee Jae Korean Society of Horticultural Science 2016 원예과학기술지 Vol.34 No.3

Clubroot caused by the protist Plasmodiophora brassicae is one of the most destructive diseases of Brassica crops. Developing Chinese cabbage cultivars with durable clubroot resistance (CR) is an important goal of breeding programs, which will require new genetic resources to be identified and introduced. In this study, we evaluated resistance to P. brassicae race 4 using 26 Chinese cabbage (B. rapa ssp. pekinensis ) cultivars compared to the clubroot-susceptible Chinese cabbage inbred line 'BP079' and the clubroot-resistant European turnip (B. rapa ssp. rapifera ) inbred line 'IT033820'. No symptoms of clubroot disease were found in 'IT033820' infected with P. brassicae race 4, whereas the Chinese cabbage cultivars exhibited disease symptoms to various degrees. The Chinese cabbage cultivars that were reported to be clubroot-susceptible were susceptible to P. brassicae race 4; however, seven of the 20 cultivars reported to be clubroot-resistant were susceptible to this race of P. brassicae to varying degrees. Resting spores of P. brassicae were abundant within the infected root tissues of 'BP079', as revealed by light microscopy and scanning electron microscopy (SEM), but they were not detected in root tissues of 'IT033820'. Although resting spores were not detected by light microscopy in root tissues of the clubroot-resistant Chinese cabbage cultivar 'Kigokoro 75', a few spores were observed by SEM. The $F_1$ hybrids from a cross between 'IT033820' and 'BP079' showed no disease symptoms, and all $BC_1P_1$ progenies from a cross between the $F_1$ hybrid and 'IT033820' exhibited a resistance phenotype. In the $BC_1P_2$ population from a cross between the $F_1$ hybrid and 'BP079', this trait segregated at a ratio of 3(R):1(S) (${\chi}^2=1.333$, p = 0.248) at a 5% significance level. Inoculated $BC_1P_2$ plants were either highly resistant or highly susceptible to the pathogen, indicating that the CR to race 4 of P. brassicae carried by 'IT033820' is dominant. In the $F_2$ population, this trait segregated at a ratio of 15(R):1(S) (${\chi}^2=0.152$, p = 0.696) at a 5% significance level, suggesting that CR in 'IT033820' is mainly controlled by two dominant genes. Therefore, 'IT033820' represents a promising genetic resource for developing durable CR breeding lines in Chinese cabbage.

Modeling of Quantum Series Resonant Converters

Gyu-Bum Joung,Chun-Taek Rim,Gyu-Hyeong Cho 대한전기학회 1989 Journal of KIEE Vol.2 No.2