• 한국컴퓨터정보학회논문지
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• 제26권2호
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• pp.119-124
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• 2021

본 연구에서는 자외선 조사 방향에 따른 화장품 살균 효율성을 확인하고자 하였다. 실험에는 그람양성균인 S.aureus에 대하여 자외선 살균의 실효 조사 각을 측정하였고 자외선 조사 방향에 따른 거리별 살균 영역의 변화를 연구하였다. 그리고 자외선 수평 조사 시 살균 효율을 높일 수 있는 방법으로서 누출 자외선을 반사시키는 방법을 제시해보았다. 그 결과 자외선 조사 각은 제품 설명에 비해 더 작게 측정되었고 자외선 조사 방향에 따른 살균 영역의 경우 수직 조사 시 시료와의 거리가 멀어질수록, 수평 조사 시 시료와의 거리가 가까울수록 살균 영역이 증가하였다. 또한 자외선 수평 조사 시 누출 자외선을 반사시키는 것으로 살균 효율을 높일 수 있는 것을 확인 하였다.

• 항공우주산업기술동향
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• 제7권2호
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• pp.115-120
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• 2009

본 논문에서는 원형마크를 이용한 항공기와 활주로간의 새로운 거리측정시스템에 관한 내용이다. 이 시스템은 항공기에 카메라와 고도계를 장착하고 활주로에 원형마크가 있어야 한다. 항공기에 장착된 카메라는 반드시 항공기의 진행방향을 향하면서 원형마크를 영상이미지형태로 간파하여 이미 장착한 고도계의 고도값과 함께 비행조종컴퓨터가 항공기와 지상간의 각도, 항공기와 원형마크간의 지상거리, 그리고 기울기거리를 계산하여야 한다. 이 시스템은 무인기의 자동착륙에 사용될 수 있다.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2004년도 춘계 학술대회논문집
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• pp.224-229
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• 2004

The objective of this work is not only to perform feasibility studies on the CFD (computational fluid dynamics) analysis for the capillary system design but also to provide an enhanced understanding of the autonomous capillary flow. The capillary flow is evaluated by means of the commercial CFD software of FLUENT, which includes the VOF (volume-of-fluid) model for multiphase flow analysis. The effect of wall adhesion at fluid interfaces in contact with rigid boundaries is considered in terms of static contact angle. Feasibility studies are first performed, including mesh-resolution influence on pressure profile, which has a sudden increase at the liquid/gas interface. Then we perform both 2D and 3D simulations and examine the transient nature of the capillary flow. Analytical solutions are also derived for simple cases and compared with numerical results. Through this work, essential information on the capillary system design is brought out. Our efforts and initial success in numerical description of the microfluidic capillary flows enhance the fundamental understanding of the autonomous capillary flow and will eventually pave the road for full-scale, computer-aided design of microfluidic networks.

• Animal Systematics, Evolution and Diversity
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• 제28권2호
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• pp.117-125
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• 2012

Many members of xanthid crabs have the black coloured fingers and are found easily in the intertidal or subtidal zone. Three xanthids, $Danielea$ $noelensis$ (Ward, 1934), $Etisus$ $anaglyptus$ H. Milne Edwards, 1834, and $Gaillardiellus$ $rueppelli$ (Krauss, 1843), are newly reported from Korean waters as a result of continuous taxonomic studies on crabs. Of these, the present specimen of $D.$ $noelensis$ has rather projecting angle on the antero-external border of the merus of the third maxilliped differed from that of the original description. The genus $Danielea$ Ng and Clark, 2003 and the genus $Etisus$ H. Milne Edwards, 1834 are also reported first time from Korean fauna. Their descriptions are provided with illustrations. Korean Xanthoidea now consists of 28 species belonging to 24 genera.

• Wind and Structures
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• 제23권4호
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• pp.301-311
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• 2016

The numerous benefits of Savonius turbine such as simple in structure, has appropriate self-start ability, relatively low operating velocity, water acceptance from any direction and low environmental impact have generated interests among researchers. However, it suffers from a lower efficiency compared to other types of water turbine. To improve its performance, parameters such flow pattern, pressure and velocity in different conditions must be analyzed. For this purpose, a detailed description on the flow field of various types of Savonius rotors is required. This article presents a numerical study on a nonlinear two-dimensional flow over a classic Savonius type rotor and a Benesh type rotor. In this experiment, sliding mesh was used for solving the motion of the bucket. The unsteady Reynolds averaged Navier-Stokes equations were solved for velocity and pressure coupling by using the SIMPLE (Semi-Implicit Method for Pressure linked Equations) algorithm. Other than that, the turbulence model using $k-{\varepsilon}$ standard obtained good results. This simulation demonstrated the method of the flow field characteristics, the behavior of velocity vectors and pressure distribution contours in and around the areas of the bucket.

• 대한기계학회논문집A
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• 제24권11호
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• pp.2845-2852
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• 2000

When welding a car frame with one spot welding there are same limitations because many parts of it cannot be simplified by one spot welding alone. It is presented two spot welding model for the description of the spot welding which is usually used in a car frame structure. This study primarily covers fatigue behavior taking spot welded SPCC(Steel plate carbon C) with different ungget intervals as a tension shear specimen. It was prepared that intervals between two nuggets are varied as 9mm, 14mm, and 20mm respectively. The tensile tests and fatigue tests were executed to know the mechanical properties under static and fatigue load condition. In addition, the relationship between fatigue life and nugget intervals was illustrated by finite element method.

• 비파괴검사학회지
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• 제26권3호
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• pp.153-161
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• 2006

A simulation program SIMULTSONIC is under development at CNDE to help determine and/or help optimize ultrasonic probe locations for inspection of complex components. SIMULTSONIC provides a ray-trace based assessment for immersion and contact modes of inspection. The code written in Visual C++ operating in Microsoft Windows environment provides an interactive user interface. In this paper, a description of the various features of SIMULTSONIC is given followed by examples illustrating the capability of SIMULTSONIC to deal with inspection of canonical objects such as pipes. In particular, the use of SIMULTSONIC in the inspection of very thin-walled pipes (with 450 urn wall thickness) is described. Ray trace based assessment was done using SIMULTSONIC to determine the standoff distance and the angle of oblique incidence for an immersion mode focused transducer. A 3-cycle Hanning window pulse was chosen for simulations. Experiments were carried out to validate the simulations. The A-scans and the associated B-Scan images obtained through simulations show good correlation with experimental results, both with the arrival time of the signal as well as with the signal amplitudes.

• 한국광학회지
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• 제9권4호
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• pp.258-263
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• 1998

준탄성광산란(QELS)을 이용하여 지름이 0.3$\mu\textrm{m}$인 폴리스티렌구의 평균지름을 측정하였다. 폴리스티렌구가 표준입자로 사용되기 위하여는 평균지름의 불확도가 수 % 이내가 되어야 한다. 본 연구에서는 QELS장차중 시료용기의 정렬방법 및 온도측정방법을 특별히 보완하여 계통오차를 대폭 줄였다. 표준입자 인증물질인 NIST SRM 1691 (0.269$\pm$0.007$\mu\textrm{m}$: TEM; 0.275$\pm$0.007$\mu\textrm{m}$:QELS)을 측정하여 평균지름이 0.2730.006$\mu\textrm{m}$ 인 결과를 얻었다. 개선된 측정방법 및 측정불확도를 상세히 기술하였으며 NIST의 측정결과와 비교하였다.

• Journal of Biosystems Engineering
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• 제14권4호
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• pp.242-250
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• 1989

The performance of a vertical type centrifugal distributor of granular materials was studied by means of mathematical models and experimental investigations. To develop the mathematical description of particle motion, some assumptions were made. The distribution process consisted of three stages: the entrance of a particle to the blade, the motion of the particle on the blade, and the motion of the particle in the air. The physical properties of fertilizer, which affected the particle motion, were investigated: bluk density, coefficient of friction, coefficient of restitution, and particle size distribution. The particle motion were simulated by using a computer. A prototype distributor was designed and constructed for experimental tests. The following conclusions were drawn from the computer simulation and experiment results. 1. The fertilizer may slide or roll at the point of contact when they impact on the blade and move along the blade. 2. The interaction among fertilizers may prevent them from bouncing. 3. When fertilizers roll on the blade, rolling resistance is one of the factors affecting the particle's motion. 4. The trajectory angle and position of fertilizers from a disc depend on the blade position and particle shape, but the rotating speed of the disc affected them only slightly.

• International Journal of Aeronautical and Space Sciences
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• 제14권4호
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• pp.369-378
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• 2013

This paper presents a vision/LiDAR integrated navigation system that provides accurate relative navigation performance on a general ground surface, in GNSS-denied environments. The considered ground surface during flight is approximated as a piecewise continuous model, with flat and slope surface profiles. In its implementation, the presented system consists of a strapdown IMU, and an aided sensor block, consisting of a vision sensor and a LiDAR on a stabilized gimbal platform. Thus, two-dimensional optical flow vectors from the vision sensor, and range information from LiDAR to ground are used to overcome the performance limit of the tactical grade inertial navigation solution without GNSS signal. In filter realization, the INS error model is employed, with measurement vectors containing two-dimensional velocity errors, and one differenced altitude in the navigation frame. In computing the altitude difference, the ground slope angle is estimated in a novel way, through two bisectional LiDAR signals, with a practical assumption representing a general ground profile. Finally, the overall integrated system is implemented, based on the extended Kalman filter framework, and the performance is demonstrated through a simulation study, with an aircraft flight trajectory scenario.