• 대한기계학회논문집B
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• 제26권8호
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• pp.1115-1122
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• 2002

The present experiment investigates the effects of pore density f of aluminum foam heat sinks, the jet-to-jet spacing X and the nozzle plate-to-target surface spacing H of 3$\times$3 square impinging arrays on the averaged Nusselt number. The performance of the aluminum foam heat sinks and the rectangular plate heat sink is evaluated in terms of the enhancement factor. /equation omitted/. The multiple impinging jet with X/d=4.0 displays higher Nusselt numbers than single impinging jet for 12.0$\leq$H/d$\leq$20.0. With the variation of the jet-to-jet spacing, the aluminum foam heat sink of 10 PPI show higher Nusselt numbers than the 20 and 40 PPI aluminum foam heat sinks. Further, the 10 PPI aluminum foam heat sink demonstrates 26% higher enhancement factor than the rectangular plate heat sink in the range of 7000$\leq$Re$\leq$11000.

• 대한기계학회논문집
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• 제14권3호
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• pp.610-616
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• 1990

본 연구의 주요 목적은 표면균열의 상호간섭 효과를 선 스프링 모델을 이용하 여 해석하여 그 결과를 비교, 검토하는 것이다. 먼저 선 스프링 모델의 이론적 배경 을 설명하고 이를 바탕으로 개발된 ABAQUS 유한요소 프로그램을 이용하여 평판구조물 에 표면균열이 한개 존재하는 경우에 대한 해석을 수행하여 이 방법의 타당성을 확인 해 보고자 한다. 또한 평판 구조물 및 원통형 구조물에 2개의 표면 균열이 존재하는 경우에 대하여 해석을 수행하여 표면균열의 상호간섭 효과를 밝혀보고자 한다.

• Geomechanics and Engineering
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• 제32권6호
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• pp.639-652
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• 2023

Stepped earth slopes incorporated with anti-slide piles are widely utilized in landslide disaster preventions. Explicit consideration of the three-dimensional (3D) effect in the slope design warrants producing more realistic solutions. A 3D limit analysis of the stability of pile stabilized stepped slopes is performed in light of the kinematic limit analysis theorem. The influences of seismic excitation and surcharge load are both considered from a kinematic perspective. The upper bound solution to the factor of safety is optimized and compared with published solutions, demonstrating the capability and applicability of the proposed method. Comparative studies are performed with respect to the roles of 3D effect, pile location, pile spacing, seismic and surcharge loads in the safety assessments of stepped slopes. The results demonstrate that the stability of pile reinforced stepped slopes differ with that of single stage slopes dramatically. The optimum pile location lies in the upper portion of the slope around L_x/L = 0.9, but may also lies in the shoulder of the bench. The pile reinforcement reaches 10% universally for a looser pile spacing D_c/d_p = 5.0, and approaches 70% when the pile spacing reaches D_c/d_p = 2.0.

• JSTS:Journal of Semiconductor Technology and Science
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• 제2권1호
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• pp.56-58
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• 2002

A closed form expression for the quality factor of the spiral inductor, methodologically, is presented as a function of the inductance ($L_{ind}$), metal-line width (W), spacing (S), inner and the diameter ($D_i$). For a given inductance, the dependences of quality factor on W, S, and $D_i$ are analyzed, and suggested the design optimization guidelines.

• 콘크리트학회논문집
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• 제12권2호
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• pp.43-51
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• 2000

This study is to investigate for the frost resistance of high-flowing concrete using finely ground granulated blast-furnace slag with experimental parameters, such as type of binder, type of superplasticizer and method of curing. The resistance to freezing and thawing of high-flowing concrete by type of binder and superplasticizer is presented differently. Though the frost resistance of high-flowing concrete is satisfactory under standard condition, it is required that high-flowing concrete has entrained air like plain concrete. Because the critical spacing factor, being capacity of frost resistance, of high-flowing concrete is longer that of plain concrete, the frost resistance of high-flowing concrete, using finely ground granulated furnace blast slag, is superior to that of plain concrete.

• Computers and Concrete
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• 제17권2호
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• pp.281-294
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• 2016

The increased awareness of electromagnetic wave hazards has prompted studies on electromagnetic shielding using conductive materials in the construction industry. Previous studies have explored the effects of the types of conductive materials and their mix proportions on the electromagnetic shielding performance; however, there has been insufficient research on the effect of the geometry of the conductive materials on the electromagnetic shielding performance. Therefore, in this study, the dependence of the electromagnetic shielding performance on the cross-sectional geometry, diameter and length of fibers was investigated. The results showed that the electromagnetic shielding performance improved when the fiber length increased or the diameter decreased, but the effect of the cross-sectional geometry of the fibers was smaller than the effect of the fiber spacing factor.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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• pp.890-893
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• 2004

In this study, Spiral inductors on the $SiO_2/Si$(100) substrate were fabricated by the magnetron sputtering method. Cu thin film with the thickness of 2 ${\mu}m$ was deposited on the substrate. Also we fabricated square inductors through the wet chemical etching technique. The inductors are completely specified by the turn width and the spacing between spirals. Both the width and spacing between spirals were varied from 10 to 60${\mu}m$ and from 20 to 70 ${\mu}m$, respectively. Inductance and Q factor dependent on the frequency were investigated to analyze performance of spiral inductors.

• 대한인간공학회지
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• 제32권5호
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• pp.449-457
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• 2013

Objective: The aim of this study is to investigate the effect of Hangul font on reading speed when texts are displayed on the computer screen. Background: Reading performance is influenced by fonts. However, there are few studies of Hangul font from a cognitive perspective. Fonts could affect reading performance directly and indirectly, interacting with other visual-perceptual factors such as size, word spacing, and line spacing. Method: In experiment 1, two variables were manipulated; a frame condition(square frame non-square frame) and a stroke condition(serif sans-serif). According to each condition, one of the four fonts was applied to the texts. The height of the four fonts was controlled. The participants were asked to read aloud the presented texts. In experiment 2, the non-square frame fonts were adjusted to have approximately the same size, width, letter spacing, and word spacing as the square frame fonts. The experimental design and task used in experiment 2 were identical with experiment 1. Results: In general, reading speed was faster in the square frame fonts than in the non-square frame fonts. The reading speed was not significantly different across stroke conditions. Conclusion: The frame of Hangul font significantly influenced reading speed. These results suggest that the type of Hangul font is a factor to affect reading performance. Application: The frame of fonts should be considered in designing of new fonts. The square frame fonts should be the preferred choice to enhance legibility.

• Geomechanics and Engineering
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• 제36권1호
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• pp.71-81
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• 2024

This study analyzes the pull-out behavior of tunnel-type anchorage under various joint conditions, including joint direction, spacing, and position, using a finite element analysis. The validity of the numerical model was evaluated by comparing the results with a small-scaled model test, and the results of the numerical analysis and the small-scaled model test agree very well. The parametric study evaluated the quantitative effects of each influencing factor, such as joint direction, spacing, and position, on the behavior of tunnel-type anchorage using pull-out resistance-displacement curves. The study found that joint direction had a significant effect on the behavior of tunnel-type anchorage, and the pull-out resistance decreased as the displacement level increased from 0.002L to 0.006L (L: anchorage length). It was confirmed that the reduction in pull-out resistance increased as the number of joints in contact with the anchorage body increased and the spacing between the joints decreased. The pull-out behavior of tunnel-type anchorage was thus shown to be significantly influenced by the position and spacing of the rock joints. In addition, it is found that the number of joints through which the anchorage passes, the wider the area where the plastic point occurs, which leads to a decrease in the resistance of the anchorage.

• 한국방사선학회논문지
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• 제10권5호
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• pp.359-365
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• 2016

투시조영촬영은 인체 내부의 조직이나 장기를 검사할 때 시행하며 특히 척추 질환의 진단 및 시술에 사용된다. 영상증배관(image intensifier tube)을 사용하는 투시조영 촬영장비는 영상에서 중심부보다 주변부에 왜곡이 나타난다. 본 연구에서는 교정 알고리즘을 적용하여 교정전과 교정후의 수직길이비 왜곡비율과 대각길이비의 왜곡비율을 측정하였다. 수직길이비의 측정결과는 교정후의 표준편차가 교정전보다 0.04감소하였고 대각길이비의 측정결과는 교정후의 표준편차가 교정전보다 0.06감소하여 교정 후 투시영상의 왜곡이 감소되었다. 향후 교정 알고리즘의 적용과 성능향상을 통해서 영상왜곡을 감소시키면 요추디스크의 치료를 위한 수핵감압술시 요추천자의 정확한 위치를 찾는데 도움을 줄 것으로 사료된다.