• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 학술대회
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• pp.374-377
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• 2008

The prediction of the separation trajectories of the external stores released from a military aircraft is an important task in the aircraft design area having the objective to define the operational and release envelopes. This paper presents the results obtained for store separation by employing commercial sorftwares, FLUENT and CFD-FASTRAN. FLUENT treats the rigid body motion by employing the remeshing scheme. CFD-FASTRAN uses the chimera(overset) grid and interpolations. It was found that, for the prediction of the trajectories and behavior of the stores separated from the wing, both codes shows the good agreement with the experimental results.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년 추계학술대회논문집
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• pp.374-377
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• 2008

The prediction of the separation trajectories of the external stores released from a military aircraft is an important task in the aircraft design area having the objective to define the operational and release envelopes. This paper presents the results obtained for store separation by employing commercial sorftwares, FLUENT and CFD-FASTRAN. FLUENT treats the rigid body motion by employing the remeshing scheme. CFD-FASTRAN uses the chimera(overset) grid and interpolations. It was found that, for the prediction of the trajectories and behavior of the stores separated from the wing, both codes shows the good agreement with the experimental results.

• Journal of Microbiology
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• 제41권2호
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• pp.144-147
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• 2003

Listeria monocytogenes is a pathogen of major concern to the food industry and the potential cause of severe infections such as listeriosis. Early detection of this foodborne pathogen is important in order to eliminate its potential hazards. So, immunomagnetic separation (IMS) has been suggested as a means of reducing the total analysis time and for improving the sensitivity of detection. Atomic force microscopy (AFM) has been used for measuring the topographic properties of sample surfaces at nanometer scale. In this study, we used AFM to confirm both the sensitivity and the specificity of IMS. Regarding AFM analysis, the length and the width of the bacteria, which were in agreement with literature values, were found to be 2.993 $\mu\textrm{m}$ and 0.837 $\mu\textrm{m}$, respectively. As a result, AFM helped us both characterize and measure the bacterial and bead structures.

• Structural Engineering and Mechanics
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• 제85권1호
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• pp.119-133
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• 2023

Impact event is the key factor influencing the operational state of the mechanical equipment. Additionally, nonlinear factors existing in the complex mechanical equipment which are currently attracting more and more attention. Therefore, this paper proposes a novel hybrid-separate identification strategy to solve the force identification problem of the nonlinear structure under impact excitation. The 'hybrid' means that the identification strategy contains both l1-norm (sparse) and l2-norm regularization methods. The 'separate' means that the nonlinear response part only generated by nonlinear force needs to be separated from measured response. First, the state-of-the-art two-step iterative shrinkage/thresholding (TwIST) algorithm and sparse representation with the cubic B-spline function are developed to solve established normalized sparse regularization model to identify the accurate impact force and accurate peak value of the nonlinear force. Then, the identified impact force is substituted into the nonlinear response separation equation to obtain the nonlinear response part. Finally, a reduced transfer equation is established and solved by the classical Tikhonove regularization method to obtain the wave profile (variation trend) of the nonlinear force. Numerical and experimental identification results demonstrate that the novel hybrid-separate strategy can accurately and efficiently obtain the nonlinear force and impact force for the nonlinear structure.

• 한국자기학회지
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• 제15권2호
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• pp.76-80
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• 2005

환경정화 등의 기능성을 부여할 수 있는 고분자자성체가 토양 오염물처리에 사용될 수 있는지 여부를 살펴보았다. 본 연구에서는 수산화기를 지닌 마이크로 고분자자성체를 분체로 걸러진 토양$(<0.025{\cal}mm)$, 물과 함께 혼합하고 교반시킨 후 1.2 Tesla의 자력을 지닌 자석으로 자성체를 분리하였다. 이때 고려되어진 인자는 토양과 고분자자성체의 비율, 토양과 물의 비율, 반응용기의 크기 그리고 자력의 크기였다. 토양과 고분자자성체의 분리실험 결과, 고분자자성체와 물의 양이 분리도에 영향을 미친 반면 반응용기의 크기와 자력은 이 소규모의 실험에서 별다른 영향이 없었다. 본 실험을 통하여 전체적으로 반응조건을 최적화시켜 $90{\~}100{\%}$의 분리도를 달성할 수 있었다. 이로서 기능성고분자를 환경 처리에 적용함에 있어서, 수처리 뿐만 아니라 토양처리에도 사용이 가능함을 확인하였다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2009년도 제33회 추계학술대회논문집
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• pp.253-256
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• 2009

과팽창 상태 추력 노즐 내부의 측력(Lateral Force)발생에 대한 기초적 연구 분석을 실험적, 수치 해석적 방법으로 수행하였다. 엔진 정지 과정시 추력 노즐 내에 발생하는 압력진동을 조사하였다. 구동 압력비 변화에 따른 벽 압력 분포를 측정 및 쉴리렌 가시화를 수행하였다. RSS(Restricted Shock Separation)에서 FSS(Free Shock Separation)로 천이하는 순간 벽 압력 피크값이 발생하였다.

• Journal of the Optical Society of Korea
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• 제10권2호
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• pp.63-66
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• 2006

In microband-induced fiber gratings, polarization properties and birefringence are investigated as a function of an applied line force. With the transmission curves associated with the maximum and minimum resonant wavelengths, the polarization-dependent behaviors are analyzed. By increasing the transverse line force, the resonance wavelength for an incident light polarized to the same direction of the force is blue-shifted as much as 0.69 nm/(N/cm) while that for the other polarization is insensitive. Using the resonant wavelength separation corresponding to the force variation, the transverse effective index change or modal birefringence variation is obtained. The ratio of modal birefringence versus applied line force is ${\Delta}B/{\Delta}f_x={\sim}8.38{\times}10^{-7}$.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 춘계학술발표대회
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• pp.446-448
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• 2000

In this study, we investigated the theoretical and experimental study for separation of solid-liquid suspensions of water and fine particles using acoustic standing wave. When the acoutic force was not applied, the separation efficiency was decreased as flow rate was increased. When it was applied, the separation efficiency was maintained over 95%.

• 한국산학기술학회논문지
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• 제18권8호
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• pp.378-385
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• 2017

본 연구는 플라스틱 부품의 체결에 널리 활용되고 있는 스냅핏의 설계에 관하여 연구하였다. 이탈방지 기능이 우수한 이탈방지 스냅핏은 형상과 체결 메카니즘이 복잡하여 기존의 이론식에 기반한 체결력과 이탈력을 해석적으로 구할 수가 없다. 따라서 본 연구에서는 이탈방지 스냅핏에 대하여 체결 메커니즘을 분석하고, 실험계획법에 기반하여 체결력 및 이탈력을 측정하고, 분산분석을 통하여 회귀식을 도출하였다. 실험계획은 중심합성계획을 사용하였다. Polybutylene terephthalate를 이용하여 시편을 제작하여 미소인장시험기를 이용하여 체결력과 이탈력을 측정하였다. 설계인자는 Length, Width, Thickness, Interference 등 4개를 선정하였으며, 2차 회귀모형을 이용하여 체결력과 이탈력에 대한 회귀식을 도출하였다. Length와 Width가 증가할수록 체결력은 낮아졌으며, Thickness와 Interference는 증가할수록 체결력이 증가하였다. 이탈력은 체결력과 반대의 결과를 나타내었다. 유한요소법을 이용하여 체결 역학에 대하여 분석하였다. Width는 체결단계에서 단면관성모멘트의 증가를 통한 보의 강성 증가 효과 보다는, 오히려 길이 증가에 따른 연성증대로 인하여 체결력을 감소시키는 것으로 나타났다. 낮은 체결력과 높은 이탈력을 위한 인자들의 영향도는 서로 상반되는 것으로 나타났다. 적정 수준의 이탈력을 유지하면서 체결력을 최소화하는 설계가 필요한 것으로 나타났다.

• 한국기계가공학회지
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• 제10권3호
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• pp.39-46
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• 2011

The automotive air conditioning hose is used for connecting the components of air conditioner in a vehicle. The hose is usually manufactured by the swaging process to connect the rubber hose with the metal fitting at the end of the hose. In case that the clamping force is small, the refrigerant gas in the hose can leak locally under the severe operating circumstances. The practical test of clamping force is performed by means of the measurement of separation force. In this study, the swaging process of a hose is simulated with the finite element method, to investigate the effect of friction coefficient on the clamping force. The contact condition is used in consideration of real manufacturing process, and the material properties for the Mooney-Rivlin model is obtained by the experimental results. The result interpretations are focused on the contact forces, which is displayed graphically with respect to friction coefficient, on the surfaces between the hose and the metal fittings.