• 수산해양기술연구
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• 제37권1호
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• pp.1-8
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• 2001

This study deals with the experimental and numerical investigations to design the high performance otter board. Experiment was carried out to determine the most effective slot size of single-slot cambered otter board in the circulation water channel of BAEK KYUNG IND. Co. LTD. Numerical analysis was done by the commercial CFD code, FLUENT, to provide some valuable physical interpretations and finally to design the otter board section by numerical method. The major results are as follows ; 1. In experiment, the maximum lift and drag coefficients of simple cambered type otterboard were 1.41, 0.55, respectively, at the angle of attack $28^\circ$, while those of slot one with slot size 0.02C (C denotes the chord length) were 1.72, 0.42 at the angle of attack $24^\circ$. 2. The hydrodynamic characteristics depending upon slot size shows the greatest at 0.02C of the slot size. 3. Numerical results well visualized the streamlines, pressure fields, and speed vectors of a simple cambered and slot cambered otter board with slot size 0.02C. The slot cambered one with slot size 0.02C was shown that pressure field was distributed moderately on front and back side of otter board. And, the delay and decrease of separation were favorably achieved by flow through slot. 4. Computed result on the pattern of hydrodynamic field and the values of $C_L$ and $C_D$ by the commercial CFD code, FLUENT, show almost the same as those of the experimental result.

• 한국의학물리학회지:의학물리
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• 제1권1호
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• pp.61-68
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• 1990

We have designed the calculation model(AMC method) of electron output for the cut-out fieldsand studied the influence of shielding block size. The output of electron was measured in the water phantom at dmax, for 20 $\times$ 20cm$^2$ cone size electron beams from CL/1800 linear accelerator(Varian, USA), Which generates the energy of 6, 9, 12, 15 and 18MeV electron beams. The shielding blocks were rectangular or squre shaped, low melting point alloy. We can predict the output from the arbitrarily rectangular shaped block within 1% error. by using the AMC method, which considers the contribution of the collimator(block) scatter and the phantom scatter.

• 한국정밀공학회지
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• 제27권2호
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• pp.25-28
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• 2010

The micro fabrication on the mold material using picosecond laser ablation processing has been studied. We used the two kind of system with picosecond laser. First one is two mirror type scanner and telecentric f-theta lens. Second one is X-Y stage and objective lens. By using these system, the $100{\mu}m$ size chess patterning and $2{\mu}m$ size patterning was fabricated. Especially $2{\mu}m$ size patterning on the mold material can be used as the decorative rainbow color logo for industrial field. In this paper, it is proved the picosecond laser is effective tool for the laser ablation processing.

• 한국재료학회지
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• 제4권5호
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• pp.581-589
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• 1994

인가자장하에서 성장한 $Co_{83}Cr_{17}$ 박막의 자가적 특성 및 미세구조를 조사하였고, 인가자장을 가하지 않은 경우에 성장한 박막과 그 특성 및 미세구조를 비교 하였다. 인가자장은 박막의 포화자화와 수평방향 보자력에는 아무런 영향을 주지 못하였지만, 수직보자력과 유효수직이방성자계를 감소시켰다. 또한 천이층의 결정립경과 두께는 인가자장에 의해 영향을 받지 않았지만, C축배향성은 약간 악화되었다. 또한 TEM사진은 인가자장의 유무에 관계없이 박막의 두께가 두꺼워질수록 (002)방위의 결정립 등이 우선적으로 성장함을 보여주었다.

• 한국응급구조학회지
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• 제21권1호
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• pp.17-44
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• 2017

Purpose: This study aimed to identify the effects of cardiopulmonary resuscitation (CPR) training using a meta-analysis by effect size. Methods: The effect sizes for each variable and the overall effect size for the collected data were identified. The homogeneity verification of the effect size and the difference among the average effect sizes for each mediation variable were determined. Results: The overall average effect size for CPR training was 1.747. Homogeneity verification of the overall effect size was a Q-value of 3716.962, which was statistically significant (p=.000) when${\alpha}=.05$. CPR training showed statistically significant differences depending on age (p=.002), sex (p=.006), number of trainees (p=.000), research design (p=.000), training method (p=.027), and practical training tools (p=.000). Conclusion: CPR training can effectively improve knowledge, skills, and attitudes about CPR. The results of this meta-analysis contribute to the development of more effective educational guidelines for future CPR training and the advancement of the CPR education field.

• 천문학회지
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• 제38권2호
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• pp.109-112
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• 2005

We present the design, expected performance, and current status of the wide field near-infrared camera (OAOWFC) now being developed at Okayama Astrophysical Observatory, NAOJ, NINS. OAOWFC is a near-infrared survey telescope whose effective aperture is 91cm. It works at Y, J, H, and $K_s$ bands and is dedicated to the survey of long period variable stars in the Galactic plane. The field of view is $0.95 {\times} 0.95 deg^2$ which is covered by one HAWAII-2 RG detector of 2048 ${\times}$ 2048 pixels with the pixel size of $18.5 {\mu}m\;{\times}\;18.5{\mu}m$, that results in the sampling pitch of 1.6 arcsec/pixel. OAOWFC can sweep the area of $840 deg^2$ every 3 weeks, attaining a limiting magnitude of 13 in $K_s$ band. It allows us to observe long period variables embedded in the Galactic plane where interstellar extinction is severe in optical.

• 전기전자학회논문지
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• 제5권2호
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• pp.121-127
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• 2001

Actual system apparatuses are necessary in order to verify the efficiency and stability of photovoltaic(PV) generation systems considering the size of solar panel, the sort of converter type, and the load conditions and so on. Moreover, it is hardly possible to compare a certain MPPT control scheme with others under the exactly same weather and load conditions as well. For the purpose of solving above mentioned difficulties in a laboratory basis, a transient simulation of PV generation system using real field weather conditions is indispensable. A straightforward simulation scheme with cost effective hardware structures under real weather conditions is proposed in this paper using EMTDC type of transient analysis simulators. Firstly, a solar cell has been modeled with VI characteristic equations, and then the real field data of weather conditions are interfaced to the EMTDC through Fortran program interface method. As a result, the stability and the efficiency analysis of PV generation systems according to various hardware structures and MPPT controls are easily possible under the exactly same weather conditions.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 추계학술대회 논문집 학회본부 A
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• pp.52-54
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• 2000

In PV power generation system study, huge system apparatuses are needed in order to verify the effect of system efficiency and stability considering the size of solar panels, the sort of converter types, and the load conditions and so on. And also, under the same weather and load conditions it is impossible to compare a certain MPPT control scheme to others. In this paper, in order to obtain effective solutions for the above mentioned topics, the solar cell array is simulated with it's VI characteristic equations, and the real field data of weather conditions is interfaced to EMTDC using Fortran program interface method. Consequently the simulation of PV power generation system using field data is realized in this paper, and acceptable results, which show close match between the real data of PV panel and the simulated data, were obtained.

• 한국기계가공학회지
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• 제8권1호
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• pp.57-63
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• 2009

Magneto-Rheological(MR) fluid composes of a base fluid and ferromagnetic particles less than tens of micrometer size dispersed in the fluid. It is called as a smart material because its rheological properties are changable by a magnetic field. Its important applications are active devices such as controllable dampers and controllable clutches. The merit of those products is that their functional characteristics are controllable such that they enable active control strategies. This paper proposes an idea for machine tool applications of the MR fluid clutch as a safety device for power transmission. FEM has been used for magnetic field analyses and the results are compared with some former experiments. Some design syntheses of the MR clutches are suggested and hopefully considered that it may be an effective safety device for power transmission of machine tools.

• Journal of Biosystems Engineering
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• 제6권1호
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• pp.15-27
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• 1981

극소형(極小形) 동력경운기(動力耕耘機)(3.5PS:KC-450)의 포장작업성능(圃場作業性能)을 조사분석(調査分析)하고 이에 대(對)한 이용범위(利用範圍)를 결정(決定)하고저 1980년(年) 3월(月)부터 1980년(年) 10월(月)까지 안성읍(安城邑) 석정동(石井洞) 시험포장(試驗圃場)에서 8PS(DT-85), 5PS(DT-40) 경운기(耕耘機)와 대비(對比)하여 耕耘(경운), 쇄토(碎土), 배토작업(培土作業)에 대(對)한 포장작업성능(圃場作業性能)을 조사(調査) 분석(分析)한 결과(結果)를 종합(綜合)하면 다음과 같다. 변속단수별(變速段數別) 작업능률(作業能率)과 포장작업(圃場作業) 효율비교(效率比較) 시험(試驗)에서는 1. 작업속도(作業速度)가 0.9m/sec일때 KC-450기(機)의 이경작업능률(犁耕作業能率)은 125분(分)/10a 무료 DT-85기(機)보다 26분(分)/10a 정도(程度)낮았다. 2. 작업속도(作業速度)를 1m/sec로 이경작업(犁耕作業) 할때에 KC-45기(機)의 포장작업성능(圃場作業性能)은 82%로 DT-85기(機)보다 5% 높았다. 3. 동일(同一) 작업속도(作業遠度)의 쇄토작업(碎土作業)에 있어서 작업능률(作業能率)은 DT-40기(機)와 DT-85기(機)가 높았고 포장작업효율(圃場作業效率)은 KC-450기(機)와 DT-40기(機)가 높았다. 4. 동일(同一) 작업속도(作業遠度)의 배사작업(培士作業)에 있어서 공시기(供試機) 모두 작업능률(作業能率)은 별차이(別差異)가 없었고 포장작업효율(圃場作業效率)은 KC-450기(機), DT-40기(機), DT-85기(機)의 순(順)으로 높았다. 구획규모별(區劃規模別) 작업능력(作業能力) 비교(比較) 시험(試驗)에서는 5. 구획(區劃) 면적(面積)이 클수록 작업능률(作業能率)은 공(共)히 향상(向上)되나 구획면적(區劃面積)이 8a이하(以下)에서는 KC-450기(機)가 작업능력면(作業能力面)에서나, 포장효율면에서 보다 유리(有利)하였다. 작업심도별(作業深度別) 작업능률(作業能率)은 비교(比較) 시험(試驗)에서는 6. DT-85로는 심경(深耕)의 능률적(能率的)인 중작업(重作業)에 유리(有利)하였고 KC-450기(機)는 경심(耕深) 12cm의 모든 작업(作業)에서 운전조작(運轉操作)이 용이(容易)하고 포장작업효율(圃場作業效率)이 타기종(他機種)에 비(比)하여 높았다. 7. 이하(以下)의 결과(結果)로 KC-450기(機)는 채소원예(菜蔬園藝), 약초(藥草), 연초(煙草), 비닐하우스등(等)의 소구획(小區劃), 소규모(小規模) 농작업(農作業)에 신기종(新機種)으로 개발(開發)이 요망(要望) 된다고 사료(思料)된다.