• Title/Summary/Keyword: asymmetrical

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Effect of Roll Gap Geometry on the Evolution of Strain States and Textures during Asymmetrical Rolling in AA1050 (AA1050 판재의 비대칭 압연 시 변형률 상태와 집합조직 발달에 미치는 압연변형 형상의 영향)

  • Kang, H.G.;Nah, J.J.;Huh, M.Y.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2006.05a
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    • pp.219-221
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    • 2006
  • Asymmetrical rolling was performed by rolling AA 1050 sheets with different velocities of upper and lower rolls. In order to study the effect of roll gap geometry on the evolution of strain states and textures during asymmetrical rolling, the reduction per rolling pass was varied. After asymmetrical rolling, the outer thickness layers depicted shear textures and the center thickness layers displayed a random texture. With decreasing reduction per an asymmetrical rolling pass, the thickness layers depicting shear textures increases. The strain states associated with asymmetrical rolling were investigated by simulations with the finite element method (FEM).

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Evolution of Strain States and Textures During Symmetrical/Asymmetrical Cold Rolling (냉간 대칭/비대칭 압연시 압연변형율 상태와 집합조직의 형성)

  • Huh Moo-Young;Lee Jae-Pil;Lee Jae-Hyup
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2004.08a
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    • pp.19-24
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    • 2004
  • Symmetrical and asymmetrical rolling was performed in AA 1050 sheets. Asymmetrical rolling was carried out by using different roll velocities of upper and lower rolls. The effect of the reduction per rolling pass on the formation of textures and microstructures during symmetrical and asymmetrical rolling was studied. In order to intensify the shear deformation, symmetrical and asymmetrical rolling was carried out without lubrication. The strain states associated with rolling were investigated by simulations with the finite element method (FEM). A fairly homogeneous residual shear strain throughout the sheet thickness was observed after asymmetrical rolling. Symmetrical rolling with a high friction gave rise to a strong net shear strain gradient in the sheet thickness.

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Effect of friction between roll and sample on residual shear strains in AA1050 sheet during asymmetrical rolling (비대칭 압연한 AA1100 판재에서 잔류전단변형에 미치는 롤과 재료간의 마찰의 영향)

  • 지영규;정효태;허무영
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2003.10a
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    • pp.156-158
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    • 2003
  • Sheets of aluminum alloy 1050 were asymmetrically cold rolled in a rolling mill with different roll speeds. In order to promote the shear deformation during asymmetrical rolling, cold rolling without lubrication was performed. The variation of the shear strain state during asymmetrical rolling was tackled by means of FEM calculations. Asymmetrical rolling gave rise to the development of pronounced residual shear strain gradients throughout the thickness layers.

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Development of Texture in Aluminum 1100 Sheets during Asymmetrical Rolling. (비대칭 압연시 알루미늄 1100 판재에서 집합조직 형성)

  • 지영규;정효태;허무영
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2003.05a
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    • pp.105-108
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    • 2003
  • Sheets of aluminum alloy 1100 were asymmetrically cold rolled in a rolling mill with different roll speeds. In order to promote the shear deformation during asymmetrical rolling, cold rolling without lubrication was performed. The evolution of texture components during asymmetrical rolling was investigated by the calculation of the orientation distribution function (ODF) using the monoclinic sample symmetry. The strain state during asymmetrical rolling was tackled by means of FEM calculations. Asymmetrical rolling gave rise to the development of pronounced strain gradients throughout the thickness layers which resulted in the formation of strong texture gradients in the aluminum sheet.

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Development of Deformation Texture in Aluminum Sheets during Asymmetrical Rolling with a Roll Speed Ratio of 1.5/l.0 (롤속도 비 1.5/l.0 비대칭 압연 시 알루미늄 판재에서 변형집합조직의 형성)

  • 지영규;정효태;허무영
    • Transactions of Materials Processing
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    • v.12 no.3
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    • pp.244-250
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    • 2003
  • Sheets of aluminum alloy 1100 were asymmetrically cold rolled in a rolling mill with different roll speeds. In order to promote the shear deformation during asymmetrical rolling, cold rolling without lubrication was performed with a roll speed ratio of 1.5/l.0. The evolution of texture components during asymmetrical rolling was investigated by the calculation of the orientation distribution function (ODF) using the monoclinic sample symmetry. The strain state during asymmetrical rolling was tackled by means of FEM calculations. Asymmetrical rolling gave rise to the development of pronounced strain gradients throughout the thickness layers which resulted in the formation of strong texture gradients in the aluminum sheet.

Effect of Deformation Parameters on The Evolution of Strain State During Asymmetrical Rolling in Aluminum Sheet (알루미늄 판재의 비대칭 압연 시 변형률 상태에 미치는 압연 변수의 영향)

  • Kang H. G.;Park S. H.;Huh M. Y.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2005.10a
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    • pp.460-462
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    • 2005
  • Asymmetrical rolling was performed with different working roll speeds of upper and lower rolls. In order to promote the shear deformation during asymmetrical rolling, various deformation parameters of initial sheet thickness, rolling reduction, roll speed ratio and roll radius are considered. The evolution of texture during asymmetrical rolling was shown by the calculation of orientation distribution function (ODF). The effect of deformation parameters on shea. deformation were investigated by simulations with the finite element method (FEM). Asymmetrical rolling gave rise to the development of pronounced strain gradients throughout the thickness layers which resulted in the formation of strong texture gradients in the sheet.

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Improvement of shear deformation by controlling reduction per a rolling pass during asymmetrical cold rolling in AA 5052 (AA5052 판재의 비대칭 냉간압연 시 압연 패스당 압하율 제어에 의한 전단 변형 향상)

  • Kang, H.G.;Han, Y.H.;Huh, M.Y.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2007.05a
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    • pp.226-228
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    • 2007
  • During asymmetrical cold rolling in AA 5052 sheet a reduction per a rolling pass was varied to investigate the effect of the ratio of the contact length between the roll and sample ($l_c$) to the sheet thickness (d) on the formation of shear textures. In order to intensify the shear deformation during asymmetrical rolling, AA 5052 sheet was asymmetrically cold rolled without lubrication by using different roll velocities of upper and lower rolls. Asymmetrical rolling with $l_c$/d=1.8 led to the formation of texture gradients throughout the sheet thickness in which the outer thickness layers depicted shear textures and the center thickness layers displayed a rolling texture. Asymmetrical rolling with $l_c$/d=3.1 gave rise to the formation of shear textures in the whole through-thickness layer. The strain states associated with asymmetrical rolling were investigated by the finite element method (FEM) simulation. FEM results indicated that the evolution of deformation texture in a thickness layer is strongly governed by integrated values of strain rates and along the streamline in the roll gap.

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The design of the EDEA gain flattening filter using an asymmetrical directional coupler (비대칭 구조의 커플러를 이용한 EDFA 이득평탄필터 설계)

  • 조준용;이경식
    • Korean Journal of Optics and Photonics
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    • v.13 no.5
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    • pp.373-376
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    • 2002
  • An asymmetrical directional coupler with two nonidentical fibers has, for the first time, been proposed and analyzed for an EDFA gain flattening filter (GFF). The characteristics of the transmission spectra of the GFFs have been theoretically investigated for the core spacings, the coupling lengths and the fiber parameters of the asymmetrical directional coupler. The analytical results show that an EDFA gain spectrum with flatness of ~7 ㏈ can be flattened to within $\pm$0.75 ㏈ over a bandwidth of 30 nm by using the asymmetrical directional coupler-based GFF.

A study on the Structure and Design Concept of Asymmetrical Building with 4 Purlins in the Joseon Dynasty (조선시대 측4량가 건축의 구조와 특징)

  • Kim, Bue-Dyel;Lee, Jong-Seo
    • Journal of architectural history
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    • v.28 no.6
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    • pp.7-18
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    • 2019
  • This study is to find out the design concept of asymmetrical building with 4 purlins mainly in Sungkyunkwan(Confucian Shrines), Changgyeonggung palace and Changdeokgung palace The results are as follows: First, asymmetrical building with 4 purlins has the same height pillars, which was useful to control the side lenght and put a higher pillar without limit. Second, the side length of the asymmetrical building with 4 purlins is between 12 to 14 Ja[尺]. It's relatively longer than the minimum length(12 Ja) of 5 purlins architecture seen in later Joseon dynasty. Third, asymmetrical building with 4 purlins was not an anomalous structure when compared to 3 purlins and 5 purlins. It was actually a traditional style, unlike the current architectural recognition nowadays, which mainly focused on the balanced roof structure. These examples show that the architectures in Early Joseon dynasty were planned and constructed first according to the plane division that fit in a specific use or space.

A Study on Development of a Hearing Impairment Simulator considering Frequency Selectivity and Asymmetrical Auditory Filter of the Hearing Impaired (난청인의 주파수 선택도와 비대칭적 청각 필터를 고려한 난청 시뮬레이터 개발에 관한 연구)

  • Joo, Sang-Ick;Kang, Hyun-Deok;Song, Young-Rok;Lee, Sang-Min
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.4
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    • pp.831-840
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    • 2010
  • In this paper, we propose a hearing impairment simulator considering reduced frequency selectivity and asymmetrical auditory filter of the hearing impaired, and we verified the reduced frequency selectivity and asymmetrical auditory filter affected in speech perception through experiments. The reduced frequency selectivity has made embodied by spectral smearing using LPC(linear prediction coding). The shapes of auditory filter are asymmetrical different with each center frequency. Hearing impaired person which has hearing loss was differently changed with that of normal hearing people and it has different value for speech of quality through auditory filter. The experiments confirmed subjective test and objective test. The subjective experiments are composed of 4 kinds of tests: pure tone test, SRT(speech reception threshold) test, and WRS(word recognition score) test without spectral smearing, and WRS test with spectral smearing. The experiment of the hearing impairment simulator was performed from 9 subjects who have normal ears. The amount of spectral smearing was controlled by LPC order. The asymmetrical auditory filter of proposed hearing impairment simulator was simulated and then some tests to estimate the filter's performance objectively were performed. The objective experiment as simulated auditory filter's performance evaluation method used PESQ(perceptual evaluation of speech quality) and LLR(log likelihood ratio) for speech through auditory filter. The processed speech was evaluated objective speech quality and distortion using PESQ and LLR value. When hearing loss processed, PESQ and LLR value have big difference according to asymmetrical auditory filter in hearing impairment simulator.