MIRA Notchback Reference Car 표면유동가시화

전중환,김용환,조광륜,노상길,이응호,Chun, Chung-Hwan,Kim, Yong-Hwan,Cho, Kwang-Ryun,Roh, Sang-Kil,Lee, Eung-Ho 대한기계학회 2000 大韓機械學會論文集B Vol.24 No.10

A surface flow visualization of a MIRA notchback reference car was conducted using a 1/4 -scale model in the POSTECH wind tunnel. The flow separation and reattachment phenomen a around A-pillar, C-pillar, backlight, and trunk were discussed with the help of the distributions of singular points such as nodes, saddles, and spiral foci. The locations of the singular points on the trunk and the backlight from experimental results are compared with those of CFD results using the turbulence modeling of RNG k -${\varepsilon}$ and RSM.

Effect of Ca Addition on the Damping Capacity of Mg-Al-Zn Casting Alloys

전중환,문정현 대한금속·재료학회 2015 METALS AND MATERIALS International Vol.21 No.4

The influences of Ca addition on the microstructures and damping capacities of AZ91-(0~2)%Ca casting alloys were investigated, on the basis of the results of X-ray diffractometry, optical microscopy, scanning electron microscopy and vibration tests in a single cantilever mode. The amount of intermetallic compounds decreased with increasing Ca content up to 0.5%, above which it increased; the average cell size showed the opposite tendency. All alloys exhibited similar damping levels in the strain-amplitude independent region. Considering the very low solubility of Ca in the matrix, and that most of the Ca elements are consumed by the formation of the Al2Ca phase and incorporation into the Mg17Al12 phase, this would be ascribed to the almost identical concentrations of Ca solutes distributed in the matrix. In the strain-amplitude dependent region, however, the AZ91-0.5%Ca alloy possessed the maximum damping capacity. From the viewpoint of microstructural evolution with Ca addition, the number density of compound particles is considered to be the principal factor affecting the damping behavior in the strain-amplitude dependent region.

돼지용 전자태그 개발을 위한 돼지 귀의 크기에 관한 연구

전중환,연성찬,김두환,장홍희,Jeon J.H.,Yeon S.C.,Kim D.H.,Chang H.H. 한국축산환경학회 2006 축산시설환경학회지 Vol.12 No.2

This study was carried out to investigate the relationship between the physical dimensions of ear and age for swine. The physical dimensions of ear and weight for twenty pigs were investigated on 1, 20, 40, 90, 120, and 150 days of age, respectively. The thickness of ear was measured at the upper, middle, and lower part of fore perimeter, and the middle and lower part of hind perimeter. The length of ear was measured for width and height. The thickness of ear increased rapidly from 1 day to 20 days of age, then it developed gradually after that period of time. The thickness at the lower part of fore perimeter increased most rapidly from 1 day to 20 days of age. In the length of ear, width increased gradually whereas height increased rapidly from 1 day to 90 days of age and then they almost did not. All the regression equations between the physical dimensions of ear and age were best represented by $Y=a+b\;X^{0.5}$. These results suggest that RFID has to be installed on the middle part of hind perimeter and an ID chip has to be installed on the lower part of fore perimeter.

산란계의 열환경별 특이음에 대한 음성학적 분석

전중환,연성찬,하정기,이승주,장홍희,Jeon, J.H.,Yeon, S.C.,Ha, J.K.,Lee, S.J.,Chang, H.H. 한국축산학회 2005 한국축산학회지 Vol.47 No.4

본 연구는 산란계가 적정 환경, 더운 환경 그리고 추운 환경에서 특이하게 내는 특이음을 분류한 후 이들을 음성학적으로 판별할 수 있는지를 규명하고자 수행되었다. 일반 발성음은 총 5가지 형태, 더위stress 특이음은 1가지 형태, 그리고 추위stress 특이음은 총 3가지 형태로 각각 나타났다. 기본주파수, 음의 강도, 음의 길이 및 포먼트에 대하여 열환경별 발성음간 유의차를 분석한 결과 모든 parameter에서 유의차가 인정되었으나, Discriminant 분석을 실시하였을 때 음의 길이, 제 1포먼트, 제 3포먼트 및 제 4포먼트가 다른 parameter들 보다 유용한 parameter로 나타났다. 이상의 결과들을 종합해 볼 때, 산란계는 열환경 변화에 따라 특이음을 내었으며, 이들 특이음은 기본주파수, 음의 강도, 음의 길이 및 포먼트 등과 같은 parameter들에 의하여 음성학적으로 판별될 수 있었다. The aim of this study was to divide vocalizations of laying hens (Hy-Line Brown) into general vocalizations (GVs), heat stress-related vocalization (HSV), and cold stress-related vocalizations (CSVs) and to determine if they are classified by the discriminant function analysis method. Thirty laying hens, 65-wk-old, were recorded using digital video recorders 2 times from 10:00 to 14:00 h in each thermal environment (thermoneutral: $22.0{\pm}1.8^{\circ}C$, too hot: $32.0{\pm}2.0^{\circ}C$, too cold: <TEx>$8.0{\pm}1.9^{\circ}C)$ after a 7 day acclimation period. When the laying hens were not recorded, they were kept in thermoneutral conditions. The GVs, HSV, and CSVs were divided based on the shapes of spectrums and spectrograms. The GVs, HSV, and CSVs were identified as 5, 1, and 3 types, respectively. Pitch, intensity, duration, formant 1, formant 2, formant 3, and formant 4 among the thermal environment-related vocalizations were significantly different (P<0.001). The discrimination rate determined by discriminant function analysis was 86.2%. These results suggest that HSV and CSVs are present and may be used as an indicator of the thermal environment.

주조 및 불연속 석출물 미세조직을 가지는 Mg-Al 합금의 진동감쇠능

전중환,Jun, Joong-Hwan 한국열처리공학회 2021 熱處理工學會誌 Vol.34 No.5

In this study, damping capacities were comparatively investigated for Mg-9%Al alloy with as-cast (AC) and fully discontinuous precipitates (DPs) microstructures, respectively. The DPs microstructure was obtained by solution treatment at 678 K for 24 h, followed by furnace cooling to RT. The AC microstructure was typically characterized by partially divorced eutectic β(Mg₁₇Al₁₂) phase particles distributed along the α-(Mg) matrix cell boundaries. The DPs microstructure showed lamellar morphology consisting of α and β thin layers with various interlamellar spacings. The DPs microstructure had better damping capacity than the AC microstructure in the strain-amplitude independent region, while in the strain-amplitude dependent region, the damping behavior was reversed. In view of the microstructural features of AC and DPs, the lower concentration of Al in the α-(Mg) phase for the DPs microstructure and the lower β phase number density for the AC microstructure would be responsible for the higher damping capacities in the strain-amplitude independent and strain-amplitude dependent regions, respectively.

T6 열처리 및 저온 장시간 등온 시효한 Mg-Al 합금의 경도 및 진동감쇠능 비교

전중환 한국열처리공학회 2023 熱處理工學會誌 Vol.36 No.5

Hardness and damping characteristics of fine discontinuous precipitates (DPs) microstructure generated by low temperature long term isothermal aging were investigated in comparison with those of T6 heattreated microstructure composed of DPs and continuous precipitates (CPs) in Mg-9%Al alloy. In this study, T6 and fine DPs microstructures were obtained by isothermal aging at 453 K for 24 h and at 413 K for 336 h, respectively, after solution treatment at 693 K for 24 h. The DPs microstructure exhibited higher hardness than the T6 microstructure, which is related to the lower (α + β) interlamellar spacing of the DPs. The DPs microstructure possessed better damping capacity than the T6 microstructure in the strain-amplitude independent region, whereas in the strain-amplitude dependent region, the reverse behavior was observed. The damping tendencies depending on strain-amplitude were discussed based on the microstructural features of the T6 and DPs microstructures.

지식의 합치와 상리적 통섭 - 인문학과 자연과학의 상생을 위하여 -

전중환 동국대학교 동서사상연구소 2017 철학·사상·문화 Vol.0 No.23

Consilience is in the spotlight. The attempts to integrate the humanities/social sciences and the natural sciences, however, have been harshly criticized as being subject to "reductionism", "scientism", or "disciplinary imperialism" by many humanists. This paper suggests that the gist of Consilience is the mutual consistency among various disciplines. Further, consilience understood in that way may open the avenue for the humanities and the sciences, as equal partners, to cooperate in building a novel, convergent systems of knowledge. The main gist of the concept "consilience", shared by a variety of scholars, requires that explanations offered by different disciplines should be consistent and not contradictory, thereby delineating a coherent picture of humans and the external world. As such, consilience is essentially a mutually beneficial project where the great branches of the knowledge equally cooperate with each other. Overall, natural sciences have achieved consilience, whereas the humanities/social sciences have not yet achieved it. Novel, convergent disciplines such as brain science, evolutionary psychology, and biological anthropology, are now making a bridge connecting the two cultures. Nevertheless, it seems that many humanists still believe that consilience is a reductionist project where the natural sciences attempt to dominate the humanities/social sciences. This is incorrect, as good explanations involve reduction. Further, I argue that consilience would provide an opportunity to greatly advance the humanities/social sciences, by making out the consistency of the knowledge. 통섭이 각광을 받는 시대다. 그러나, 정작 인문학/사회과학과 자연과학을 융합하려는 시도는 대다수 인문학자들에게 ‘환원주의’, ‘과학주의’, 혹은 ‘학문제국주의’라는 비난을 받는 실정이다. 이 논문은 통섭의 핵심은 지식 분야 사이의 상호 합치임을 보이고, 이렇게 이해된 통섭은 인문학과 자연과학이 서로 동등한 파트너로 협력하여 새로운 융복합 지식 체계를 함께 건설하는 길을 열어줌을 주장한다. 여러 연구자들이 공유하는 통섭 개념의 교집합은 여러 학문 분과가 내놓는 설명들이 서로 모순되지 않고 합치됨으로써 결과적으로 인간과 세계에 대한 하나의 일관된 밑그림이 자연스레 도출되어야 한다는 것이다. 이러한 의미에서, 본래 통섭은 학문의 큰 가지들이 대등하게 협력하여 모두 시너지 효과를 얻는 상리적인 기획이다. 자연과학에서는 통섭이 이루어졌지만, 안타깝게도 인문학/사회과학에서는 아직 이루어지지 못했다. 뇌과학, 진화심리학, 생물인류학 등등 새롭게 등장한 융합학문들은 실제로 인문학/사회과학과 자연과학을 활발히 연결하는 작업을 수행하고 있다. 그러나 여전히 통섭은 자연과학이 인문학/사회과학을 지배하고자 하는 환원주의적 기획이라고 믿는 인문학자들이 많다. 설명의 근간은 환원이므로, 환원주의에 대한 이러한 인식은 오해다. 나아가, 통섭은 일선 연구자들에게 지식의 합치를 권유함으로써 인문학과 사회과학이 새롭게 도약하는 계기를 제공함을 주장하였다.

Mg-Al-Al4C3 주조재의 진동감쇠능 (초)

전중환,이건하,김기태 대한금속재료학회 ( 구 대한금속학회 ) 2007 대한금속재료학회 학술대회 개요집 Vol.2007 No.1

Descent Systems, Paternity Uncertainty and Cousin-directed Altruism

전중환,윤지영,최재천 한국생태학회 2008 Journal of Ecology and Environment Vol.31 No.3

Jeon and Buss (2007) found that human altruistic tendencies towards different categories of cousins are adaptively regulated as a consequence of paternity uncertainty. Since the study sample was drawn from a large US city where the effects of patrilineality may be week, the question of whether descent systems also independently affect cousin-directed altruism remained unanswered. We replicated the cousin-directed altruism study in a population of urban Korean college students, who have lived in a highly patrilineal society. As predicted, mother’s sister’s children were favored the most, followed by both mother’s brother’s and father’s sister’s children. Contrary to our predictions, however, father’s brother’s children was more, not less, favored than either mother’s brother’s or father’s sister’s children. We discuss why this cross-cultural difference may be observed with regard to the highly patrilineal culture in Korea. Jeon and Buss (2007) found that human altruistic tendencies towards different categories of cousins are adaptively regulated as a consequence of paternity uncertainty. Since the study sample was drawn from a large US city where the effects of patrilineality may be week, the question of whether descent systems also independently affect cousin-directed altruism remained unanswered. We replicated the cousin-directed altruism study in a population of urban Korean college students, who have lived in a highly patrilineal society. As predicted, mother’s sister’s children were favored the most, followed by both mother’s brother’s and father’s sister’s children. Contrary to our predictions, however, father’s brother’s children was more, not less, favored than either mother’s brother’s or father’s sister’s children. We discuss why this cross-cultural difference may be observed with regard to the highly patrilineal culture in Korea.

하절기 우사관리 요령

전중환,Jeon, Jung-Hwan 한국낙농육우협회 2011 낙농·육우 Vol.31 No.7