캠축의 구조 진동 응답 및 응력

최명진,Choi, Myung-Jin 한국음향학회 2013 韓國音響學會誌 Vol.32 No.3

캠축의 진동 응답을 구하기 위해 캠축을 불균형 다단계 로터 베어링계로 해석하였으며, 복잡한 형상과 하중조건을 고려하여 유한요소법을 사용하였다. 유한요소 방정식을 유도한 후에 Newmark 법을 사용하여 진동 응답을 구하였다. V-8 엔진 캠축의 회전 진동 응답을 구하여 측정치와 비교하였다. 캠축의 변동 응력을 구하고, 응력 집중 효과를 고려한 다음에 Goodmann 식에 근거하여 피로 해석을 수행하였다. 캠축의 회전 진동에서는 굽힘 효과가 지배적이며, 인접하는 베어링 간격에 가장 큰 영향을 받는다. 캠축에 가해지는 하중의 변화가 클 경우에는 하중의 변화에 상응하여 시간에 따라 변화하는 베어링 계수를 적용하여야 함을 알 수 있었다. To get vibration responses, a camshaft is modelled as an unbalanced multiple rotor bearing system. Because of complex geometry and complicated load conditions, the finite element method is used. After the finite element equation of the system is constructed, Newmark's method is used to get the vibration responses. Whirl vibration responses of a V-8 engine camshaft are estimated and compared with measured responses. After the fluctuating stresses are obtained, fatigue analysis is performed based upon the modified Goodman's equation. Stress concentration effects are considered. In the whirl vibration of camshafts, the bending effect is dominant, and the bending deformation is dependent upon the span length between the adjacent bearing journals. For high speeds, the fluctuations of excitation forces are large, and it is known that nonlinear time varying bearing coefficients should be used for analysis.

시뮬레이션에 의한 성덕대왕 신종 음관의 특성

최명진,박홍을,Choi Myung-Jin,Park Hong-Eul 한국시뮬레이션학회 2005 한국시뮬레이션학회 논문지 Vol.14 No.4

To investigate the characteristics of the sound-pipe on the top of King Song-Dok bell, using computer simulation, the throat impedance was evaluated for the straight pipe and conical pipes with varying taper angles. When sound propagates in a rigid walled, unflanged circular pipe with wavelength larger than radius, the acoustic motion is planar, much as in a bar. The incident sound waves are reflected at the end of pipe and some of them are transmitted. The reflection coefficient and radiation impedance of the sound-pipe of King Song-Dok bell were calculated, and the results demonstrated that the high frequency sound is radiated through the sound-pipe. It behaves like a frequency filter.

발효 옻 추출물의 생리활성 및 단회 경구 투여 독성시험

최명진,이승진,장승희,홍주헌,정희경,박승춘,Choi, Myung-Jin,Lee, Seung-Jin,Jang, Seung-Hee,Reza, Md. Ahsanur,Hong, Joo-Heon,Jung, Hee-Kyoun,Park, Seung-Chun 대한수의학회 2010 大韓獸醫學會誌 Vol.50 No.3

In this study, we investigated the biological activities such as anti-tumor, anti-oxidant and antiinflammatory activities as well as single oral dose toxicity of fermented Rhus verniciflua extract (FRVE). In order to examine anti-tumor activity of FRVE, the sarcoma 180 cells were treated with FRVE at various concentrations (0.03, 0.3, 3 and 30 mg/mL) in microtetrazolium (MTT) assay. In MTT assay, all the cells treated with FRVE at various concentrations have shown a significant difference compared with control (p < 0.05). In xanthine oxidase inhibition assay to examine the antioxidant activity, the xanthine oxidase inhibition rate of FRVE at 1.5 mg/mL and 15 mg/mL was $85{\pm}15.01%$ and $99{\pm}16.02%$, respectively. Nitric oxide production in RAW 264.7 cells showed that FRVE showed a significant anti-inflammation effect at 3 mg/mL (p < 0.05). In single oral dose toxicity study, no differences were observed between control and treated groups in clinical signs, body weight gains, feed and water consumptions. The results indicated that lethal dose 50 ($LD_{50}$) of FRVE was found to be higher than 5,000 mg/kg in this experiment. From the above results, we may suggest that FRVE might have useful as a material for functional food and/or animal pharmaceutics.

감마선 검출용 $HgI_2$ 소자 제작 및 특성 평가

최명진,이홍규,강영일,임호진,최승기,Choi, Myung-Jin,Lee, Hong-Kyu,Kang, Young-Il,Lim, Ho-Jin,Choi, Seung-Ki 대한방사선방어학회 1991 방사선방어학회지 Vol.16 No.2

상온에서 사용할 수 있는 감마선 검출 소자로서 $HgI_2$ 소자의 응용성을 판단하기 위하여 기상 성장법으로 $HgI_2$ 단결정을 성장시켰고 이를 이용하여 검출 소자를 제작한 후 감마선 검출 특성을 조사하였다 성장된 단결정의 비저항과 전하 운반자 포획 밀도는 상온에서 각각 $10^{11}{\Omega}\;cm$와 $1.8{\times}10^{14}/cm^3$였으며 단결정의 Photoluminescence를 측정한 결과 성장된 $HgI_2$ 단결정의 밴드갭의 온도계수는 20K부터 77K에서 $-1.53{\times}10^{-4}eV/K$였다. 감마선 검출실험 결과 제작된 $HgI_2$ 검출 소자는 상온에서 우수한 계수 특성과 시간에 대한 선형적 축적 계수 특성을 나타내었으나 온도변화에 따라 계수의 특성의 변화는 심하였다. The $HgI_2$ single crystal which can be used for the ${\gamma}-ray$ detector at room temperature was grown by Temperature Oscillation Method. The low temperature photoluminescence, specific resistivity and trap concentration of $HgI_2$ single crystal were investigated. Three main luminescence bands were observed at 2.30eV, 2.20eV and 2.00eV at 20K, related to the excitons, I-vacancies and impurities, respectively. The specific resistivity and trap concentration of $HgI_2$ single crystal were $10^{11}{\Omega}\;cm\;and\;1.8{\times}10^{14}/cm^3$ at room temperature, respectively. Also the radiation detecting system was deviced by $HgI_2$ ${\gamma}-ray$ detector, one chip microprocessor, LCD module and personal computer. The prepared $HgI_2$ ${\gamma}-ray$ detector showed a good linearity of ${\gamma}-radiation$ dose for standard ${\gamma}-ray$.

Mycoplasma hyopneumoniae에 대한 Origanum vulgare 추출물의 항마이코플라즈마 및 항염증 효과

최명진,황미현,최재영,이중수,박승춘,Choi, Myung-Jin,Hwang, Mi-Hyun,Choi, Jae-Young,Lee, Joong-Su,Park, Seung-Chun 대한수의학회 2009 大韓獸醫學會誌 Vol.49 No.3

In the present study, ten herbal extracts, Citrus unshiu Markovich, root and stem of Berberis koreana, Morus alba, Dendrobium moniliforme, Aster gramineus, A. scabar, Alisma canaliculatum, Fallopia japonica and Origanum (O.) vulgare were determined to examine anti-mycoplasmal activity. Among them, O. vulgare extract (OVE) showed strong anti-mycoplasmal activity and was analyzed by gaschromatography/ mass spectrometry (GC/MS). As the results, OVE was consisted of carvacrol (68.78%), o-cymene (9.80%), terpinene (7.61%) and thymol (4.03%) as main ingredients. To investigate inflammatory activity by intact pathogenic Mycoplasma hyopneumoniae (M. hyo) at 30 $\mu$g/ml, we examined induced transcription of proinflammatory cytokines such as cyclooxygenase-2, tumor necrosis factor-a, interleukin (IL)-1, IL-6 and inducible nitric oxide synthase in RAW 264.7 cells. With the above results, we further investigated whether OVE could reduce inflammation induced by M. hyo at minimal inhibitory concentration. The result showed that 32 $\mu$g/ml of OVE inhibited nitric oxide production by 60%. This study also evaluated the combination of OVE with antibacterials against M. hyo for application. Based on these results, it could be concluded that M. hyo induces inflammation in RAW 264.7 cells and OVE protects this inflammation, indicating that OVE may be useful for industrial animals.

국방연구개발사업 수행위험 측정방안 연구

최명진,나호영,이상헌,Choi, Myung-Jin,Na, Ho-Young,Lee, Sang-Heon 한국군사과학기술학회 2009 한국군사과학기술학회지 Vol.12 No.3

The risk management is a method to identify and to handle risk factors. In this paper, we introduce a methodology that can be used to measure of system's performance risk by combining system's TPM(technical performance measures) in the R&D(research and development) program for defense acquisition. By applying the suggested procedure, we can monitor risk trends in R&D program by calculation of system's overall TPM and find out where management should target to reduce or remove the system's performance risk.

The Multiple Traveling Purchaser Problem for Minimizing the Maximal Acquisition Completion Time in Wartime

최명진,문우범,최진호,Choi, Myung-Jin,Moon, Woo-Bum,Choi, Jin-Ho The Korea Institute of Military Science and Techno 2011 한국군사과학기술학회지 Vol.14 No.3

In war time, minimizing the logistics response time for supporting military operations is strongly needed. In this paper, i propose the mathematical formulation for minimizing the maximal acquisition completion time in wartime or during a state of emergency. The main structure of this formulation is based on the traveling purchaser problem (TPP), which is a generalized form of the well-known traveling salesman problem (TSP). In the case of the general TPP, an objective function is to minimize the sum of the traveling cost and the purchase cost. However, in this study, the objective function is to minimize the traveling cost only. That's why it's more important to minimize the traveling cost (time or distance) than the purchase cost in wartime or in a state of emergency. I generate a specific instance and find out the optimal solution of this instance by using ILOG OPL STUDIO (CPLEX version 11.1).

극대화된 밴드갭을 갖는 켈빈 격자 구조의 아이소-지오메트릭 최적 설계

최명진,오명훈,조선호,구본용,Choi, Myung-Jin,Oh, Myung-Hoon,Cho, Seonho,Koo, Bonyong 한국전산구조공학회 2019 한국전산구조공학회논문집 Vol.32 No.4

밴드갭은 기계적 파동의 전파가 금지되는 특정 주파수 범위를 의미한다. 본 연구는 경사도 기반의 설계 최적화 방법을 사용하여 낮은 가청 주파수 범위에서 밴드갭을 갖는 3차원 켈빈 격자를 설계하는 것을 목적으로 하고 있다. 블로흐 이론을 이용하여 무한주기 격자에서의 탄성파 전파를 해석하고, 기하학적으로 엄밀한 빔 이론에서 선형화를 통해 얻은 전단 변형 가능한 빔 모델을 사용하여 격자 구조 연결선을 모델링하였다. 주어진 격자 구성에서 중립 축 및 단면 두께를 B-spline 함수를 이용한 아이소-지오메트릭 매개화를 통해 설계 변수로 정의하고, 격자 구조의 밴드갭의 크기를 극대화하는 최적 설계를 수행하였다. A band gap refers to a certain frequency range where the propagation of mechanical waves is prohibited. This work focuses on engineering three-dimensional Kelvin lattices having external band gaps at low audible frequency ranges using a gradient-based design optimization method. Elastic wave propagation in an infinite periodic lattice is investigated by employing the Bloch theorem. We model the ligaments using a shear-deformable beam model obtained by consistent linearization in a geometrically exact beam theory. For a given lattice topology, we enlarge band gap sizes by controlling the configuration of the beam neutral axis and cross-section thickness that are smoothly parameterized by B-spline basis functions within the isogeometric analysis framework.

신경망을 이용한 멀티 에이전트 기반 대공방어 단위 학습모형

최명진,이상헌,Choi, Myung-Jin,Lee, Sang-Heon 한국군사과학기술학회 2008 한국군사과학기술학회지 Vol.11 No.5

In this paper, we suggested a methodology that can be used by an agent to learn models of other agents in a multi-agent system. To construct these model, we used influence diagram as a modeling tool. We present a method for learning models of the other agents at the decision nodes, value nodes, and chance nodes in influence diagram. We concentrated on learning of the other agents at the value node by using neural network learning technique. Furthermore, we treated anti-air units in anti-air defense domain as agents in multi. agent system.

고 비저항 p - Cd80Zn20Te 의 저항성 전극형성에 관한 연구

최명진,왕진석 ( Myung Jin Choi,Jin Suk Wang ) 한국전기전자재료학회 1997 한국전기전자재료학회 춘계학술대회논문집 Vol.1997 No.0