• Title/Summary/Keyword: Front Structure

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An architectural characteristics and locality of the Joongjaesil-type pavilion in the Jirisan Mountain area (지리산권 중재실형 정자의 건축특성 및 지역성)

  • Son, Hee-Gyoung;Lee, Ho-Yeol
    • Journal of architectural history
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    • v.31 no.1
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    • pp.29-39
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    • 2022
  • The remaining Joongjaesil(中齋室)-type pavilions in the eastern part of the Jirisan Mountain area showed more complex characteristics than those in the western part. The front number of kan(間) had two, three, and four kan (間) types, but the number of kan on the side was consistent with two regardless of the number of kan on the front. The pavillion is classified into 'central type', 'towards the backward type', and 'expanded by backwards type' according to the location of Joongjaesil. Joongjaesil's size, which characterizes the characteristics of Joongjaesil-type Pavilion, is related to the building's front number of kan. Front number of kan. When this space was increased by one space to four spaces, Joongjaesil must have two spaces. The pavilion with four bays in front showed the characteristics of being concentrated in Sancheong and Jinju, the eastern part of the Jirisan Mountain area. In the eastern region, many high pavilions remain, and the upper structure of the pavilion was insignificant, but the flat shape and public construction showed strong locality.

Numerical Study of Detonation Wave Structure and Dynamics in a Circular Tube (원형관 내 데토네이션 파 구조 및 동적 특성 수치 연구)

  • Cho, Deok-Rae;Kim, Jong-Kwan;Jang, Keun-Jin;Choi, Jeong-Yeol
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2012.05a
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    • pp.278-281
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    • 2012
  • Numerical studies were performed to investigate the three-dimensional front structure and dynamics features of detonation wave propagating in a circular tube such as Pulse Detonation Engine (PDE). By carrying out a series of parametric study using one step irreversible Arrhenius kinetics model, mechanisms of the three-dimensional front structure were investigated for two-, three-, four and six-cell mode detonations. A comparison with two-dimensional results, the effects of slapping transverse waves in radial direction were confirmed. In the all muti-cell modes, the detonation front structures and smoked-records on the wall are formed by the propagation of transverse waves along the wall in clockwise and counter-clockwise while the slapping move in radial direction. And the strength of reflected waves on the curved wall is changed by the multi-dimensional confinement effect.

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Application of G-equation to large eddy simulation of turbulent premixed flame around a bluff body inside a cylindrical chamber (G 방정식을 이용한 실린더 챔버 내부 둔각물체 주위의 난류 예 혼합 화염 해석)

  • Choi Chang-Yong;Park Nam-Seob;Ko Sang-Cheol
    • Journal of Advanced Marine Engineering and Technology
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    • v.29 no.4
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    • pp.391-398
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    • 2005
  • In this investigation, turbulent premixed combustion and flame front propagation in a gas turbine combustion chamber is studied. Direct numerical simulation of turbulent reacting flows demands extremely high computational resources, especially in more complicated geometry. The alternative choice may be left for Large Eddy Simulation (LES) by which only large scales are solved directly. In combustion problems, capturing the large scales' behavior without solving the details of small scales is a difficult task. Using a transport equation for description of the flame front propagation and therefore avoiding the calculation of inner flame structure is the basic idea of this study. For this purpose. the so-called G-equation has been used by which any iso-level of the G variable provides the flame location. A comparison with the experiment indicates that the present method can predict a turbulent velocity field and also capture a instantaneous 3-dimensional flame structure.

Bare Wafer Inspection using a Knife-edge Test

  • Lee, Jun-Ho;Kim, Yong-Min;Kim, Jin-Seob;Yoo, Yeong-Eun
    • Journal of the Optical Society of Korea
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    • v.11 no.4
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    • pp.173-176
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    • 2007
  • We present a very simple and efficient bare-wafer inspection method using a knife-edge test. The wafer front surface and inner structures are inspected simultaneously. The wafer front surface is inspected visually using a knife-edge test while the inner structure is simultaneously inspected by a camera in the infrared region with a single white-light source. This paper presents a laboratory implementation of the test method with some experimental results.

Experimental study of vertical fence wake with flow separator (Flow separator가 부착된 수직벽 후류유동의 실험적 연구)

  • Choi, Young-Ho;Kim, Hyoung-Bum
    • 한국가시화정보학회:학술대회논문집
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    • 2006.12a
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    • pp.68-72
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    • 2006
  • Vertical fence has the coherent flow structure in front of the fence. In the present study, the wake change due to the flow separator in front of the vertical fence was experimentally investigated. Quantitative method was applied to study the separated shear flow field. The results show the flow separator changes the downstream shear flow and alters the curvature of separated shear layer As the freestream velocity increased, the reattachment length also increased.

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Vt Close Curve Analysis for Improving Address Discharge Characteristics in Open Dielectric Structure of AC PDP (플라즈마 디스플레이의 개방형 유전체 구조에서 기입방전특성을 향상시키기 위한 Vt 폐곡선 분석)

  • Cho, Byung-Gwon
    • Journal of the Institute of Electronics and Information Engineers
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    • v.51 no.1
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    • pp.179-184
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    • 2014
  • The discharge characteristics of an open dielectric structure were investigated, especially such as a firing voltage and related wall voltage, compared with conventional panel structure based on the Vt close curve measurement in AC plasma display panel. While the front panel of the conventional structure in AC plasma display panel was composed of the glass, electrodes, and dielectric, the open dielectric structure could easily produce the discharge between the scan and the sustain electrodes by erasing the dielectric layer between two electrodes. As the open dielectric structure differ from the conventional structure, various problems were produced when driving with the conventional driving waveform. Especially, due to the changes in the discharge firing characteristics of the open dielectric structure between the scan and the sustain electrodes on the front panel, the conventional reset waveform including the address waveform needed to be modified. In this study, the Vt close curves were measured to compare the discharge firing voltages on three electrodes in the conventional and open dielectric structure and based on the Vt close curve analysis, the modified driving waveform suitable for the open dielectric structure was proposed.

A Study on the Flame Structure and Combustion Charactexistics of a Premixed Flame Stabilized by a Streamline Step( $\Pi$) (유선형 스텝에 의해 안정화된 예혼합화염의 구조와 연소특성에 관한 연구 ($\Pi$))

  • 이재득;최병륜
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.14 no.6
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    • pp.1661-1668
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    • 1990
  • In a turbulent premixed flame stabilized by the streamline step, and dominated by a coherent eddy, a flame micro-structure was investigated with analyzing the signals of temperature, the ion current, and schieren phtographs simultaneously. Generally the contours of large scale coherent eddies of schlieren photographs was considered as the flame front, however, the main reaction can be occurred within the eddy as a structure of fine flamelets scale. The surrounding burned gas of flamelets could not propagate to a unburned mixture, obstructing flamelets from propagating to a unburned mixture. Consequently, it could restrain flashback. The main reaction region was found to be located at higher temperature of the burned gas rather than at maximum rms of fluctuating temperature. The peak probability of higher temperature was 6 times greater than that of lower temperature. As it was difficult to infer a flame structure from PDF distribution of the fluctuating temperature in form of bimodal shape, it should be taken into consideration with other informations related to the sensitive flame front, for instance, ion current.

Wave Structure Interaction by Installation of New Circular Caissons on Old Circular Caisson Breakwater (기존 원형케이슨방파제에 신규 원형케이슨 추가설치에 따른 파와 구조물간의 상호작용 영향 평가)

  • Park, Min Su
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.32 no.5
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    • pp.307-321
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    • 2020
  • The design and the construction are carried out by installation of new caissons on the back or the front of old caissons to increase the stability of old caisson breakwater. In this study, we use the eigenfunction expansion method to analyze the effects of wave structure interaction when new circular caissons are installed on the back or the front of old caissons. The comparison of numerical results between present method and Williams and Li is made, and the wave force and the wave run-up acting on each circular caisson are calculated for various parameters by considering the wave structure interaction.

Low-power Frequency Offset Synchronization for IEEE 802.11a Using CORDIC Algorithm (CORDIC을 이용한 IEEE 802.11a용 저전력 주파수 옵셋 동기화기)

  • Jang, Young-Beom;Han, Jae-Woong;Hong, Dae-Ki
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.46 no.2
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    • pp.66-72
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    • 2009
  • In this paper, an efficient frequency offset synchronization structure for OFDM(Orthogonal Frequency Division Multiplexing) is proposed. Conventional CORDIC(Coordinate Rotation Digital Computer) algorithm for frequency offset synchronization utilizes two CORDIC hardware i.e., one is vector mode for phase estimation, the other is rotation mode for compensation. But proposed structure utilizes one CORDIC hardware and divider. Through simulation, it is shown that hardware implementation complexity is reduced compared with conventional structures. The Verilog-HDL coding and front-end chip implementation results for the proposed structure show 22.1% gate count reduction comparison with those of the conventional structure.

Design and Implementation of OFDM Frequency Offset Synchronization Block Using CORDIC (CORDIC을 이용한 OFDM 주파수 옵셋 동기부 설계 및 구현)

  • Jang, Young-Beom;Han, Jae-Woong;Hong, Dae-Ki
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.45 no.5
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    • pp.118-125
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    • 2008
  • In this paper, an efficient frequency offset synchronization structure for OFDM(Orthogonal Frequency Division Multiplexing) is proposed. Conventional CORDIC(Coordinate Rotation Digital Computer) algorithm for frequency offset synchronization utilizes two CORDIC hardware i.e., one is vector mode for phase estimation, the other is rotation mode for compensation. But proposed structure utilizes one CORDIC hardware and divider. Through simulation, it is shown that hardware implementation complexity is reduced compared with conventional structures. The Verilog-HDL coding and front-end chip implementation results for the proposed structure show 22.1% gate count reduction comparison with those of the conventional structure.