• 한국정밀공학회지
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• 제19권6호
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• pp.35-42
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• 2002

Verification of tool collision Is an important issue in die and mold machining. In this paper three functions of verification for 3-axis milling machining are schematically explained. Operators of geometric models are explained at first, which will be used in the functions of verification. The first verification function is getting a collision-free region when a tool assembly and a part surface model are given. The second function estimates the shortest length of cutter shank with that the tool cuts all of a region without collision The last one is cutting simulation considering all parts of tool assembly as well as cutter blade. Proposed approaches can be easily implemented by using several basic operators of geometric model. An example to calculate collision-free region is presented also.

• Journal of Welding and Joining
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• 제15권2호
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• pp.43-53
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• 1997

The complete joining method for dissimilar press punch materials and its real-time evaluation method is not available at present. Brazing method has been used for joining them, but it is known that the welded joint by the brazing has the lower bonding efficiency and reliability than the diffusion welding. The friction welding with a diffusion mechanism in bonding was applied in this study. This work was carried out to determine the proper friction welding conditions and to analyze mechanical properties of friction welded joints of sintered carbide tool materials (SKNM50 for the blade part of press punch) to alloy steel (SCM440 for the shank part of press punch) using aluminum (A6061 for the interlayer material) as an insert material between the sintered carbide tool materials and the alloy steel. In addition, acoustic emission test was carried out during friction welding to evaluate the weld quality.

• 한국기계가공학회지
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• 제14권1호
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• pp.117-122
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• 2015

There has been a string of negligent accidents at the seaside, and there is presently a shortage of professional equipment to deal with such accidents. The purpose of this paper is to assess the development of a rescue lift. The critical load of a support pipe, and the stability of the rescue lift, were investigated using structural analysis. Critical-load analysis was used to study the effects of variations in the pipe length and the ratio of the moment of inertia. The total weight of the developed rescue lift is approximately 20.7 kg, and the lift passed the load tests.

• 한국정밀공학회지
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• 제27권8호
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• pp.62-69
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• 2010

Internal lathe machining with a boring bar is weak with respect to vibration because the bar is long and slender. Therefore, it is important to study the dynamic characteristics of a boring bar. The purpose of this study was to identify the effects of overhang and cutting conditions on the dynamic response characteristics of a boring bar. For an efficient experiment, an $L_g(3^3)$ orthogonal array was applied and the results were quantitatively analyzed by ANOVA. Overhang, feed per revolution, and depth of cut were selected as independent variables. Meanwhile, dynamic stiffness, damping ratio, damping coefficient, and acceleration were chosen as dependent variables. The vibration signal was obtained from an accelerometer attached to the boring bar, followed by visualization by a signal analyzer. The effect of overhang was found to have a significant effect on the dynamic stiffness, damping ratio, and damping coefficient, but the other variables did not. As the length of the overhang increased, the dynamic stiffness decreased and the damping ratio increased. In addition, the damping coefficient increased until the length of the overhang was 4D (where D is the shank diameter), after which it remained constant. The acceleration decreased until the overhang length was 4D, and then increased sharply when the overhang was increased further. From these results, the behavioral trend of the damping characteristics changed when its overhang length was 4D. Consequently, there is a critical point that the dynamic characteristics of boring bar change.

• 한국가금학회지
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• 제39권4호
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• pp.283-290
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• 2012

본 시험은 한국 재래계와 도입종 산란계의 육성 초기 성장능력을 비교분석하기 위하여 실시하였다. 공시계는 유전자원 관리기관에서 종란을 인수하여 부화시킨 암수 병아리 276 수를 이용하였으며, 한국 재래계 2 계통(A, B)과 도입종 산란계 3 계통(C, D, E)으로 총 5 계통의 수정률, 부화율, 육성단계별 체중, 증체량, 사료 요구율 등을 조사하였다. 수정률은 A, B, C, D 및 E계통에서 각각 93.88%, 81.75%, 82.25%, 79.25% 및 71.50% 이었고, 부화율은 5계통에서 각각 95.65%, 86.24%, 88.15%, 90.85% 및 88.11%로 나타났다. 육성률은 0~10 주령에서 A와 E계통에서는 98% 이상으로 높게 나타났고, D 계통은 86.67%로 가장 낮은 것으로 조사되었다. A계통은 육성단계별 체중에서 2주령부터 10주령까지 가장 우수하게 나타났고, 전체 기간 동안에 가장 높은 증체량을 보였다(p<0.05). 정강이 길이는 D계통이 0주령에는 낮은 수치를 보였으나, 2주령부터 점차 증가하여 10주령에서는 $56.69{\pm}3.27mm$로 가장 높은 수치를 보였다(p<0.05). A계통의 증체량과 정강이 길이 사이의 표현형 상관관계는 0~2주, 2~4주, 4~6주, 6~8주 및 8~10주령에서 각각 0.63, 0.70, 0.55, 0.50 및 0.46으로 높은 정의 상관관계를 보였고, 전 기간의 표현형 상관관계도 0.85로 높은 정의 상관관계를 보였다. D계통의 증체량과 정강이 길이 사이의 표현형 상관관계도 0~2주, 2~4주, 4~6주, 6~8주 및 8~10주령에서 각각 0.73, 0.55, 0.54, 0.24 및 0.29로 높은 정의 상관관계를 보였으며, 전 기간의 표현형 상관관계도 0.78로 높은 정의 상관관계를 보였다. 한국 재래계의 종자 산업화를 위하여 육성 후기의 능력 및 산란율 등을 추가적으로 조사할 필요가 있을 것으로 사료된다.

• 한국가금학회지
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• 제50권2호
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• pp.91-99
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• 2023

본 연구는 생산 능력이 우수한 삼계용 토종닭을 개발하기 위한 것으로 국내 고유 토종닭 종자들 간 교잡으로 생산한 6개 조합의 재래토종닭(KNC-SCYC, SCYD, SDYC, SDYD, SYYC, SYYD)과 상업용 토종실용닭인 GSP-한협 토종닭의 생산 능력을 백세미와 비교 분석하였다. 생산 능력의 검정은 품종별 각 100여수씩 총 756수를 대상으로 발생 후부터 7주령까지 생존율, 체중, 정강이 길이, 사료 섭취량, 사료요구율 및 도체율을 조사하였다. 분석 결과, 발생 후부터 7주령까지 전체 시험구의 평균 생존율은 거의 100%로서 품종 간 차이는 없었다. 체중은 모든 주령에서 품종 간에 유의한 차이를 보이며(P<0.01), 5주령 체중에서 백세미는 863.8±76.9 g, GSP-한협 토종닭은 804.7±72.5 g, 재래토종닭 조합구들의 평균 체중은 543.0±61.8 g이었다. 삼계 출하체중인 850 g 도달일령은 백세미는 34.5일, GSP-한협 토종닭은 37.5일, 재래토종닭 조합들은 45.8-48.8일로 추정되었다. 850 g 생체중 기준 도체율은 재래토종닭은 63.3%, 백세미는 60.4%, GSP-한협 토종닭은 56.1%로 분석되었다. 체중 850 g을 기준으로 품종 간 정강이 길이를 비교하였을 때 재래토종닭 KNC-SYYD구는 7.6 cm, 백세미는 7.8 cm, GSP-한협 토종닭은 8.0 cm로 측정되었다. 체중 850 g 도달일 동안 품종 간의 사료요구율을 비교하였을 때 백세미는1.81, GSP-한협 토종닭은 2.17, 재래토종닭 KNC-SCYC구는 2.27으로 나타났다. 이상의 결과를 종합할 때 토종닭의 산육 능력 및 사료 이용성은 백세미에 미치지 못하나 토종닭은 도체율이 양호하고 백세미보다 짧은 정강이 길이 때문에 삼계탕 원료육으로의 활용 가치가 높다고 판단된다. 토종닭 중 GSP-한협 토종닭과 재래토종닭 KNC-SYYD 조합 등은 상대적으로 산육능력, 정강이 길이 및 도체 성적이 우수함으로 백세미를 대체할 수 있는 토종 삼계 후보로 사료된다.

• 한국가금학회지
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• 제39권2호
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• pp.105-112
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• 2012

Genetic resource conservation of indigenous species is important to conserve terrestrial, aquatic and avian species throughout the world. The native Korean Oge (KO) chickens are important and protected indigenous avian species in Korea. This KO breed is very popular in Korea because of its external appearances of blackish color. The characterization of morphology and growth performances of KO were performed since 1980s, however the information is still not sufficient for breed selection. In this study, we compared various growth performances including body growth, tibia length, shank length, chest width, chest grith and length of tail feather between male and female chickens of KO and widely known White Leghorn (WL) breeds at 1 week, 2 weeks, 5 weeks, 10 weeks, and 24 weeks. We observed differences on various growth performances at different aged groups between KO and WL chickens. This study may help for the selection of chicken breeds based on age, body growth and meat production.

• Asian-Australasian Journal of Animal Sciences
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• 제15권3호
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• pp.401-405
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• 2002

An experiment was conducted to determine the effects of caponization on the growth performance, breast and thigh muscles physical properties and fiber diameter of the Pectoralis major and Gastrocnemius pars externa in Taiwan country chicken cockerels. Caponized birds were surgically altered at 10 weeks of age. Birds were fed grower and finisher diets ad libitum during an eighteen-week experimental period. The results indicated that the live weight and feed intake in the capons were significantly (p<0.05) higher and the shank length was significantly (p<0.05) longer than in intact birds. There were no significant (p>0.05) differences in feed conversion and mortality between two treatments at 28 weeks of age. Compared with intact birds, the capons had greater (p<0.05) tenderness in the breast and thigh muscles. Cohesion of the breast muscle in the capons was significantly (p<0.05) better than in the intact birds, but the thigh muscles were not significantly (p>0.05) affected. No treatment differences (p>0.05) were associated with cooking loss, muscle chewiness, and elasticity. The capons had a significantly (p<0.05) smaller fiber diameter in the Pectoralis major, but were not significantly (p>0.05) different in the fiber diameter of the Gastrocnemius pars externa. It is concluded that castration did not depress growth compared with the intact birds, but did improve muscle tenderness. This difference was most pronounced in the thigh muscles.

• 한국환경과학회지
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• 제18권12호
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• pp.1325-1330
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• 2009

The fumigant 1,3-dichloropropene (1,3-D) was recently proposed as a direct replacement for methyl bromide ($CH_3Br$) in soil fumigation. This study was conducted to better understand behavior phase partitioning, diffusion and volatilization of 1,3-D as affected by isomer. The Henry's law constant(KH) of cis-1,3-D and trans-1,3-D was 0.058 and 0.037 at $20^{\circ}C$, respectively. $K_H$ of cis form of 1,3-D was higher than that of trans form of 1,3-D. To compare with volatilization of 1,3-D isomer, soil column [70 cm (length)${\times}$12 cm (i.d.)] included a shank injection at 30 cm with 300 kg $ha^{-1}$. Maximum cis-1,3-D and trans-1,3-D concentration reached 57 mg $L^{-1}$ and 39 mg $L^{-1}$ at 30 cm depth at 1h after application. Cumulatively, after 10 days, 51.8% and 43.57% of applied cis-1,3-D and trans-1,3-D was emitted via volatilization, respectively. The total losses of cis-1,3-D were significantly greater than that of trans-1,3-D. Finally, cis-1,3-D and trans-1,3-D, such as isomer are dominant of 1,3-D fates in soil.

• Steel and Composite Structures
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• 제22권4호
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• pp.777-796
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• 2016

In this paper, the behavior of woven E-glass fabric composite laminate was experimentally investigated under quasi-static indentation and high velocity impact by flat-ended, hemispherical, conical (cone angle of $37^{\circ}$ and $90^{\circ}$) and ogival (CRH of 1.5 and 2.5) cylindrical perforators. Moreover, the results are compared in order to explore the possibility of extending quasi-static indentation test results to high velocity impact test results in different characteristics such as perforation mechanisms, performance of perforators, energy absorption, friction force, etc. The effects of perforator nose shape, nose length and nose-shank connection shapes were investigated. The results showed that the quasi-static indentation test has a great ability to predict the high velocity impact behavior of the composite laminates especially in several characteristics such as perforation mechanisms, perforator performance. In both experiments, the highest performance occurs for 2.5 CRH projectile and the lowest is related to blunt projectiles. The results show that sharp perforators indicate lower values of dynamic enhancement factor and the flat-ended perforator represents the maximum dynamic enhancement factor among other perforators. Moreover, damage propagation far more occurred in high velocity impact tests then quasi-static tests. The highest damage area is mostly observed in ballistic limit of each projectile which projectile deviation strongly increases this area.