환경유래 젖소유방염 저감을 위한 우분뇨 탈수 시스템의 탈수 및 유방염 원인체 제균 효과 규명

김동혁,임정주,이진주,김대근,장홍희,이승주,이윤범,장동일,이후장,민원기,김상훈,오권영,김석,Kim, Dong Hyeok,Lim, Jung Ju,Lee, Jin Ju,Kim, Dae Geun,Chang, Hong Hee,Lee, Seung Joo,Lee, Yun Beom,Chang, Dong Il,Lee, Hu Jang,Min, Won-Gi,Kim, Sang 대한수의학회 2009 大韓獸醫學會誌 Vol.49 No.3

Bovine mastitis is an important disease causing serious economic loss in dairy production and food poison in public health. Escherichia coli and Staphylococcus aureus are the major causative agents of bovine mastitis. These bacteria were found in milk and environmental condition such as feces, water, soil and so on. Bovine mastitis causative micro-organisms can survive in 1-2 weeks in feces and bed complexes. Low level of percentage of water content (PWC) of feces and bed complexes can reduce the spreading of bovine mastitis incidence from environmental contamination. In this study, we developed the fecal dehydrating system and determined the elimination rates of bovine mastitis causative agent from feces and bed complexes. To develop the fecal dehydrating system, the screw pressurized dehydrating system was used and the maximum rate of dehydrating was reached to 52% PWC using 90% PWC (wet base) of fecal and bed complexes. The elimination rates of the dehydrating system for E. coli and S. aureus were reached at 41.19 $\pm$ 7.84% to 62.55 $\pm$ 8.71% in various percentages of PWC of feces and bed complexes (80, 85 and 90%). These results suggested that the application of fecal dehydrating system would reduce the exposure of dairy cattle to bovine mastitis causing agents contaminated feces and bed complexes, and can be used for environmental bovine mastitis control avoiding misuse or abuse of chemical disinfectants and antibiotics in dairy farm.

웹을 기반으로 한 자기 주도적 MITS -초등 수학 수와 연산 영역 중심-

김동혁,고병오,최의인,Kim, Dong-Hyuk,Goh, Byung-Oh,Choi, Eui-In 한국정보교육학회 2004 정보교육학회논문지 Vol.8 No.3

Recently, there is change the environment of education due to development of Science Technology Specially, As education information on web increased by internet, using education web data by mean of medium that aids learning by computer. Also It studied method that used the Computer as learning medium through the CAI(Computer Assisted Instruction), ICAI(Intelligent CAI), and ITS(Intelligent Tutoring System). But legacy system are not support efficient method that learns to vary learner suitable learning method by individual level. Specially It is not suitable the education course to direct current course of education, and not consider different of student capability, aptitude, need, interesting, not maximized the individual growable power and effect of education. To solve the this problem, our paper suggest the web-based self-directed MITS(Multimedia ITS) that supply the needed the information on web, make the environment that can self-directed learning. To maximized effect of individual learning, our paper structured coursed, characterized, related learning contents in region of numeral at mathematics of primary school. And then integrated contents and class, design and implement the web-based MITS that consist of 4 module to escape from limitation of learner grade, learning time, learning place.

소량의 기포를 함유한 이상유체 내에서의 압력파의 전파현상

김동혁,Kim, D.-H. 한국음향학회 1989 韓國音響學會誌 Vol.8 No.1

기포 혼합 유체 내에서의 압력파의 전파 현상을 수치해석으로 연구한다. 혼합 유체 영역을 지배하는 지배 방정식을 heuristic 한 방법으로 유도하고 기포 내부 영역에는 열전달 효과를 고려할 수 있도록 에너지 방정식을 도입한다. 기포 내부의 비등온 조건은 특히 기포가 고진폭을 가지고 진동할 때 매우 중요하다. 기포 역학 방정식으로서 Keller 방정식이 채택, 변형되어 기포 외부와 내부의 coupling을 맺어준다. 실제 문제로서 충격관내 충격파의 전파 현상을 수치해석 방법으로 해석한 결과가 Noordzij 및 van Wijngaarden 의 실험 결과와 거의 일치한다. 그러나 그들에 의해 설명된 충격파 구조의 변화 원인은 가스와 액체 간의 상대 운동인데 이는 본 모델에서 고려되지 않았기 때문에 가스와 액체 간의 열전달에 의해 충격파의 구조가 변화된다고 보는 것이 타당하다. Propagation phenomena of nonlinear pressure waves in a bubbly mixture are studied. The governing equations for a bubbly mixture are derived heuristically and energy equation is incorporated with other governing equations to take thermal effects into consideration inside the bubble. This non-isothermal condition of the bubble inside is especially important when high amplitude pressure waves are treated. Keller's equation is adapted for the bubble dynamics as practical problem. Some numerical simulations are carried out for the shock tube problem using a computer program based on the above model. A comparison with experimental results of Noordzij and van Wijngaarden shows that the structure of the wave in the shock tube experiment seems to be much more significantly affected 요 the complex heat transfer phenomena inside the bubbles than by the relative translational motion between bubbles and surrounding liquid.

일본 원전 시찰기 - 오나가와 원전

김동혁,Kim, Dong-Hyeok 한국원자력산업회의 2017 원자력산업 Vol.37 No.11

Effect of different soybean meal type on ileal digestibility of amino acid in weaning pigs

김동혁,Pil Seung Heo,장재철,Song Shan Jin,Jin Su Hong,Yoo Yong Kim 한국축산학회 2015 한국축산학회지 Vol.57 No.3

An experiment was conducted to evaluate apparent (AID) and standardized (SID) ileal digestibilities of crude protein(CP) and amino acids (AA) with 6 soybean products in weaning pigs. A total of 14 weaning barrows with an initialbody weight of 6.54 ± 0.34 kg were fitted with T-cannula at the distal ileum and allotted to 7 diets containingvarious soybean products. The soybean products used in the experiment were conventional soybean meal (CSBM),SBM fermented by Aspergillus oryzae GB-107 (FSBMA), SBM fermented by Bacillus subtilis PP6 (FSBMB), UV sterilizedSBM fermented by Bacillus subtilis PP6 (UVFSBMB), SBM containing Bacillus subtilis PP6 (PSBM), and soy proteinconcentrate (SPC). Six corn-based diets were used and each of soybean products was added. All diets contained5.0 g/kg of chromic oxide as an indigestible indicator and an N-free diet was used to measure basal endogenouslosses of CP and AAs. Ileal CP digestibility did not differ by different soybean products. However, SIDs of Ile, Pheand Val were improved in pigs fed the FSBMB, UVFSBMB and SPC diets and the pigs fed the FSBMA diet showedhigher SIDs of Phe and Val compared with those fed the CSBM diet (P < 0.05). The FSBMB diet had higher SIDs inmost AAs compared with the FSBMA diet (P < 0.05), and higher SIDs of Lys, Ala, Pro, Ser, and Tyr compared withPSBM diet (P < 0.05). However, there was no response of UV-sterilization on the FSBMB in the SIDs of AAs. Theseresults suggest that SIDs of AAs could be improved by the supplementation of fermented soybean products in thediet for weaning pigs but fermentation with Bacillus subtilis is more efficient in improving ileal AA digestibility thanthat with Aspergillus oryzae. Furthermore, probiotics supplementation in the CSBM and UV-sterilization of the FSBMBhad no effects on chemical composition and ileal AA digestibility.

방화정보 - 바람의 피해와 풍공학

김동혁,Kim, Dong-Hyeok 한국화재보험협회 1993 防災와 保險 Vol.57 No.-

Nonlinear Aspects of the Frequency Response of a Gas-filled Bubble Oscillator

김동혁,김정태,이용봉,Kim, Dong-Hyuk,Kim, Jeung-Tae,Lee, Yong-Bong The Acoustical Society of Korea 1991 韓國音響學會誌 Vol.10 No.1

기포 진동 시스템에 대한 수치해석이 수행되었다. 수학적 모델은 기포역학에 대해서는 Keller의 식을, 기포내부 해석을 위해서는 Prosperetti의 식을 채택하였다. Prosperetti는 기포내부 해석을 위해 에너지 방정식을 도입하였으며 매우 정확한 해석을 가능케 하였다. 수치해석결과 기포진동의 주파수 응답곡선에 있어 전형적인 비선형 현상들을 볼 수 있었다. 이러한 비선형 현상들에는 점프현상(jump phenomena), 공진주파수의 변화, 그리고 superharmonic 공진점의 발생등이 있다. 비선형 주파수 응답은 기포진동 시스템의 초기조건에 따라 달라지는데 이에 의해 어느 가진 주파수 대역에서는 두개 이상의 해가 존재할 수 있게 된다. 기포진동 시스템에서 비선형 진동현상은 Duffing 방정식과 비교가 되는데 두 시스템은 비슷한 비선형 현상들을 가지고 있다고 볼 수 있다. A numerical analysis is carried out for the nonlinear phenomena of the bubble oscillator. The model is based on the Keller's formulation for the bubble dynamics. Interpretation of the bubble interior is based on the formulation by Prosperetti. His formulation adopts the energy equation for the analysis of the bubble interior. The numerical simulation Shows typical nonlinear phenomena in its frequency response. Among such nonlinear aspects are the jump phenomenon, the shift of natural frequency of the system, and the appearance of superharmonic resonances. It is deduced that the nonlinear frequency response is dependent upon the initial condition of the bubble oscillator and some multi-valued frequency region can appear in the response curve. Nonlinear phenomena appeared in the bubble oscillator is compared with those of the Duffing equation and it may be said that the bubble dynamic equation has similar nonlinear aspects to the Duffing equation.

재활용 절삭칩으로 제조된 AC2B 합금의 용체화 열처리에 따른 미세조직 및 기계적특성 변화

김동혁,윤종천,최창영,최시근,홍명표,신상윤,예병준,Kim, Dong-Hyuk,Yoon, Jong-Cheon,Choi, Chang-Young,Choi, Si-Geun,Hong, Myoung-Pyo,Shin, Sang-Yoon,Ye, Byung-Joon 한국주조공학회 2018 한국주조공학회지 Vol.38 No.2

Changes in the microstructures and mechanical properties of an AC2B alloy through solution heat treatment were investigated using recycled AC2B cutting chips as raw material. The as-cast microstructure of the AC2B alloy comprised ${\alpha}$-Al, $Al_2Cu$, and coarse needle-shaped phases considered to be eutectic Si and an Al-Fe-Si based intermetallic compound. After solution heat treatments at $505^{\circ}C$ for 1 h and 6 h, the samples showed complete dissolution of $Al_2Cu$ and relatively fine distribution of intermetallic compounds. Hardness test results showed that the hardness rapidly increased after the solution heat treatment for 1 h by solid solution hardening, and the increase of hardness exhibited a plateau from 1 h to 6 h. The results of the hardness and tensile tests showed that there was no visible difference in the effect of 1 h and 6 h solid solution treatment.

열음향 냉동기

김동혁,Kim, Dong-Hyeok 한국설비기술협회 1996 설비 : 공조ㆍ냉동ㆍ위생 Vol.13 No.7

열음향 냉동

김동혁,Kim, D.H. 대한설비공학회 1995 설비저널 Vol.24 No.3