• Title/Summary/Keyword: sound stress

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The Effect of Process Parameter in Direct Extrusion of Copper Clad Aluminum Composite Materials (Cu-Al 층상 복합재료의 직접압출시 공정변수의 영향)

  • 윤여권;김희남;김용수
    • Journal of the Korean Society of Safety
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    • v.15 no.4
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    • pp.28-34
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    • 2000
  • Copper clad aluminum composite materials are being used for economic and structural purposes, The development of an efficient production method of copper clad aluminum composite material rods by extrusion is very important. This paper describes experimental investigations in the direct extrusion of copper clad aluminum rods through conical dies. There are several parameters that have an influence on determining a sound clad extrusion. These variables are extrusion temperature, extrusion ratio, semi-cone angle of die, extrusion force, extrusion velocity, friction of between the container and billet, percentage of copper used and ratio of flow stress of copper to aluminum. In order to investigate the influence of extrusion temperature, extrusion ratio, semi-cone angle of die on the hot direct extrudability of the copper clad aluminum composite material rods, the experimental study have been performed with these variation.

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Piezoelectric Microspeaker by Using Micromachining Technique (마이크로머시닝 기술을 이용한 압전형 마이크로스피커)

  • Suh, Kyong-Won;Yi, Seung-Hwan;Ryu, Kum-Pyo;Min, Nam-Ki
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2005.11a
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    • pp.45-46
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    • 2005
  • The piezoelectric ZnO thin films were deposited onto Al/Si substrate in order to figure out the crystalline and the residual stress of deposited films. As the $Ar/O_2$ gas ratio is increased, c-axis orientation of deposited films is significantly enhanced and also the residual stresses of ZnO films are all compressive. They are decreased from -1.2 GPa to -950 MPa as the $Ar/O_2$ gas ratio is increased. A diaphragm-based piezoelectric microspeaker fabricated on ONO films shows about 14 mPa output pressure at 1 kHz with $8V_{peak-to-peak}$.

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ENGLISH RESTRUCTURING AND A USE OF MUSIC IN TEACHING ENGLISH PRONUNCIATION

  • Kim, Key-Seop
    • Proceedings of the KSPS conference
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    • 2000.07a
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    • pp.117-134
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    • 2000
  • Kim, Key-Seop(2000). English Restructuring and A Use of Music in Teaching English Pronunciation. JSEP 2000 voU This study has two-fold aims: one is to clarify the restructuring of English in utterance, and the other is to relate it to teaching English pronunciation for listening and speaking with a use of music and song by suggesting a model of 10-15 minute pronunciation class syllabus for every period in class. Generally, English utterances are restructured by stress-timed rhythm, irrespective of syntactic boundaries. So the rhythmic units are arranged in isochronous groups, of which the making is to attach clitic(s) to a host or head often leftwards and sometimes rightwards, which results in linking, contraction, reduction, sound change and rhythm adjustment in utterance, just as in music and song. With English restructuring focused on, a model of English pronunciation class syllabus is proposed to be put forward in class for every period of a lesson or unit. It tries to relate the focused factor(s) in pronunciation to the integrated, with teaching techniques and music made use of.

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A Study on Square Die Extrusion of Hollow Shape (중공형재의 평금형 압출에 관한 연구)

  • 이승훈;이춘만;조종래
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1996.10a
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    • pp.14-19
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    • 1996
  • This study presents development of finite element simulation program and analysis of hot extrusion through square dies with mandrel. The design of extrusion dies is still an art rather than science. Die design for a new extrusion is developed from through in-plant trials. In the present paper, three-dimensional steady-state finite element simulation program is developed. The developed system is effectively used to simulate extrusion of clamp shaped hollow section. The objective of the present paper is to study the possibility of integrating this method into the design of dies for extrusion of complex section. To obtain sound product, the distributions and effects of temperature, effective strain rate, mean strain rate and mean stress are studied.

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Applications of Semi-Solid Forming and its Problems (반용융 성형공정의 응용 및 문제점)

  • 강충길
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1997.06a
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    • pp.135-147
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    • 1997
  • The production of light metal parts using aluminum is mainly performed by die casting and squeeze casting, which directly fabricate the required shape from the liquid state. However, die casting is subject to defects such as shrinkage porosity and air trapped when molten metal enters the cavity, whilst squeeze casting also has defects due to turbulent flow in the die cavity. Both diecasting and sqeeze casting have inhomogeneous mechanical property in terms of dendritic structure during solidification. Active research has been carried out on semi-solid processing, rather than on conventional process methods such as die casting, which involve various problems. Therefore in this paper, to introduce the fundamental technology for d e design, in die casting and forging process with semi-solid materials, relationship between stress and strain of semi-solid materials, and for producing parts die design has been proposed as parameters of globulization of the microstructure and gate shape. The prevention of various defects to produce sound parts are also introduced.

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A Study on Psychological Effect of Natural Element in Rest Space of Office (오피스 휴게공간에서 자연요소의 심리적 효과에 관한 연구)

  • Kang, Min-Kyung;Lyu, Ho-Chang
    • Proceedings of the Korean Institute of Interior Design Conference
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    • 2004.11a
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    • pp.84-87
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    • 2004
  • The stress from the office environment comes from the most psychological things. Therefore, the purpose of this study is to research the psychological effect of natural element for office worker's psychological stability. This study is focused on the light, sound, air, temperature, plant, and water. Perception of these natural elements through the senses of sight, auditory, smell, and touch is effect on human body and mind directly. The application of natural elements provide a health of office workers. The result will show that, with application of the natural element, the rest space will be more powerful for health of workers. And also combination of natural element and geometric pattern will be very useful to prepare healing environment on the rest space

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The Evaluation of Fracture Toughness on Mode I for Twill CFRP/GFRP Laminated Hybrid Composites (능직 CFRP/GFRP 적층하이브리드 복합재의 Mode I 파괴인성 평가)

  • Roh, Young Woo;Kang, Ji Woong
    • Journal of the Korean Society of Safety
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    • v.35 no.5
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    • pp.9-14
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    • 2020
  • In order to realize high strength and light weight for various industrial facilities and structural materials, various new materials are applied to product design. Among them, CFRP has excellent specific strength and non-rigidity, and the scope of use is expanding throughout the industry, such as mobility products and building materials. GFRP is cheaper than CFRP, and has excellent specific strength and non-rigidity, and has excellent heat resistance and sound insulation, so it has been adopted as a core material for flooring and interior flooring. CFRP of twill weave structure has better resistance to deformation of fiber than plain weave structure, so the outermost layer is applied as twill weave structure in product design. After fabrication with DCB specimens, Mode I fracture toughness was evaluated according to the crack length. As the crack length increases, the energy release rate and stress intensity factor values tended to decrease overall.

Calculation of Material Properties with JMatPro for the Process Simulation (JMatPro를 이용한 공정해석에서의 물성계산)

  • Lee, Kyung-Hoon;Kang, Gyeong-Pil
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2008.05a
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    • pp.142-145
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    • 2008
  • Process simulation requires accurate and reliable data for a wide variety of material properties, ranging from thermal conductivity to flow stress curves. Traditionally such data are gathered from experimental sources, which has significant disadvantages in that not all of the required data is readily available, it may be from various sources that are themselves inconsistent, measurement of high temperature properties is expensive, and furthermore the properties can be sensitive to microstructure as well as to alloy composition. This article describes the development of a new multi-platform software program called JMatPro, which is based on CALPHAD methodology, for calculating the properties and behavior of multi-component alloys. A feature of the JMatPro is that the calculations are based on sound physical principles rather than purely statistical methods. Thus, many of the shortcomings of methods such as regression analysis can be overcome.

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Effect of corrugation structure and shape on the mechanical stiffness of the diaphragm

  • Kim, Junsoo;Moon, Wonkyu
    • Journal of Sensor Science and Technology
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    • v.30 no.5
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    • pp.273-278
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    • 2021
  • Here, we studied the change in the mechanical stiffness of a diaphragm according to the corrugation pattern. The diaphragm consists of a silicon oxide and nitride double layer; a corrugation pattern was formed by dry etching, and the diaphragm was released by wet etching. The fabrication of the thin film was verified using focused ion beam and scanning electron microscopy images. The mechanical stiffness of the diaphragm was obtained by measuring the surface vibration using a laser Doppler vibrometer while applying external sound pressure. Flat squares, diaphragms with square corrugations, and circular corrugation patterns were measured and compared. The stiffness of the diaphragm with a corrugation structure was found to be smaller than that without a corrugation structure; in particular, circular corrugation showed a better effect because of the high symmetry. Furthermore, the effect of corrugation was theoretically predicted. The proposed corrugated diaphragm showed comparable flexibility with the state-of-the-art MEMS microphone diaphragm.

A Study of Development and Production of Relaxing VR Content

  • Kim, Mijung
    • International Journal of Advanced Culture Technology
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    • v.9 no.4
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    • pp.194-203
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    • 2021
  • Virtual reality is being increasingly used for healing and therapy for mental health. In this study, we developed VR-based immersive content that enables virtual travel without the limitations of time and physical conditions. We aim to develop and produce VR content for relaxation and meditation using the beautiful natural scenery. To make realistic and immersive content, we took a video of natural sceneries with a small UAV connected to a VR camera. The content was developed through stitching, video editing and post-processing of the initially captured video data, and then the created VR video was inserted into the VR device. The produced content will be helpful for stress and used to heal the mind and body of exhausted modern people by providing the place with great scenery and sound in an immersive way at any time.