• Journal of Mechanical Science and Technology
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• v.19 no.10
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• pp.1950-1956
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• 2005

An analysis has been carried out to investigate the effect of the reflectivity on the temperature distribution of a glass panel by infrared radiant heating. Halogen lamps are used to heat the panel, located near the top and bottom of the rectangular chamber. The thermal energy is transferred from the lamps to the panel only by radiation and it is considered by using view factor. The conductive transfer is limited inside the panel. The results show that the uniformity of the temperature distribution of the panel is improved and, at the same time, the time for heating increases as the wall reflectivity increases. The temperature difference between the center and the corner reaches a maximum in the early stage of the heating process and then decreases until it reaches a uniform steady-state value.

• Journal of the Korean Vacuum Society
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• v.6 no.1
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• pp.44-49
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• 1997

AIN thin films were deposited on silicon and glass substrates by sputtering Al target and introducing mixed gases of argon and nitrogen into reactive RF magnetron sputter. The substrate was not heated to protect the PC (polycarbonate) substrate and the micro-sized pregroove morphology on the surface of PC substrate. But its temperature was around $100^{\circ}C$ due to the self-heating by plasma. The crystallinity, cross-section morphology and refractive index were characterized by changing various deposition parameters.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.526-527
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• 2013

기존의 발열유리 온도 제어 방법은 PTC Type 또는 NTC Type 의 온도센서를 발열유리에 부착하여 발열유리온도를 검지하여 제어를 한다. 온도센서가 발열유리 표면에 부착됨으로써 온도센서박스 및 온도센서용 통신선로가 추가적으로 필요하다. 또한 외관과 시야가 나빠진다. 이런 문제점을 해결하기 위해 본 논문에서는 실내의 온도와 실외의 온도를 검지하여 유리 표면에 온도센서가 부착하지 않은 발열유리 온도제어시스템에 관한 연구를 하였다. 그리고 실내에서 전열기로 사용하는 경우에 한하여 온도센서리스 방식의 발열유리 온도제어시스템에 관한 연구 및 실험을 하였다.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.6
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• pp.41-48
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• 2000

The Compression molding process is widely used in the automotive industry to produce parts that are large, thin, light-weight, strong and stiff. Compression molded parts are formed by squeezing a glass fiber reinforced polypropylene sheet, known a glass mat thermoplastic(GMT), between two heated cavity surfaces. In this study, the anisotropic viscosity of the Unidirectional Fiber-Reinforced Plastic Composites is measured using the parallel plastometer and the composites is treated as an incompressible Newtonian fluid. The effects of molding parameter and fiber contents ratio on longitudinal/transverse viscosity are also discussed.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.558-559
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• 2012

선박과 건축용 창유리에 발생하는 결로 결빙 현상을 방지하기 위해 발열유리를 사용 한다. 발열유리를 ON/OFF방식으로 제어하게 되면 발열유리의 종류에 따라 유리코팅이 훼손 될 우려가 있다. 발열체의 등가저항 및 열시정수가 적은 경우에는 TRAIC의 위상제어 방식을 사용해야 한다. 또한 다수의 발열유리를 제어하기 위해서는 제어기 각각의 통신선이 필요하지만 전력선통신을 이용하면 별도의 통신선이 필요가 없어진다. 그러므로 설치비용이 감소하고 외관이 좋아지며, 발열유리의 추가적 설치와 장치의 위치 변경이 용이해진다. 본 연구에서는 전력선통신과 TRIAC 위상제어 방법을 이용하여 전체 발열유리 온도제어 시스템을 구성하고, 실험을 통해 검증하였다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.5
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• pp.1106-1114
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• 1993

A composite material is composed of a reinforcement and a matrix, which determine mechanical characteristics of the molded part. There is no doubt that the properties of a composite material depend not only on the characteristics of the matrix but also on the structure of glass fiber mat and a fiber type of reinforcement. Therefore it is very important to study the composites of reinforcement and the matrix, and to control the fiber type in the process of molding of composite materials. In this study, the specimen was made of a glass fiber mat of 6-7mm thickness by scattering it in the air after cutting the glass fiber mat with needle punching makes change according to the type of needle and the number of times of stretching. First the sheet was made by means of a hot-press after accumulating a matrix and a glass fiber according to each mat structure of glass fiber. It was heated the manufactured sheet with the dry oven and molded it a secondary high temperature compression by a 30 ton oilhydraulic press. A definition of a correlation coefficient is showed up during this period and find it out with the relation of the fiber-matrix separation and the fiber orientation. We studied effects of the glass fiber mat structures on the correlation coefficient.

• Journal of the Korean Ceramic Society
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• v.18 no.1
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• pp.3-12
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• 1981

A glass-ceramics based on blast-furnace slag, with some additives to the theoretical composition in order to control properties of mother glass and the heat treatment conditions, has been investigated. The raw materials in this study were blast-furnace slag, serpentine, feldspar and quartz as mother glass ingredients. Titanium dioxide and chromite were used as the nucleating agents. Batch compositions of the prepared glasses and ceraming conditions were found by trial and error method. The optimum conditions were confirmed by analyzing several measured physical properties such as density change during heat treatment, microhardness of slag-ceramics prepared, viscosity change of glass at heat treatment temperatures, nucleation density change, dilatometric properties, differential thermal analysis, identification of the grown crystal and crystal sizes. The batch composition feasible to prepare slag-ceramics was 40% of blast-furnace slag, 25% of serpentine, 18% of feldspar and 17% of silica sand. Three percent titanium dioxide and 1% chromite of the mother glass were added as nucleating agents. The ceraming conditions under which the slag-ceramics having considerably good properties can be developed found as: "The glass was heated at 75$0^{\circ}C$ for 2 hours for nucleation, and the temperature was raised up to 1, 00$0^{\circ}C$ with a rate of 0.75$^{\circ}C$/min for crystal growth.owth.

• Korean Journal of Materials Research
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• v.5 no.8
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• pp.929-935
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• 1995

In order to develop COG (Chip On Glass) technology for LCD module interconnecting the driver IC to Al pad electrode on the glass substrate, Anisotropic Conductive Adhesive(ACA) process, the most promising one among COG technologies, was investigated. ACA process was carried out by two steps, dispensing of ACA resin in the bonding area and curing by W radiation. Load on the chip was ranged from 2.0 to 15kg and the chip was heated at about 12$0^{\circ}C$. In resin, the density of conductive particles coated with Au or Ni at the surface were 500, 1000, 2000 and 4000 particles/$\textrm{mm}^2$, and the diameter of particles were 5, 7 and 12${\mu}{\textrm}{m}$. As a result of the experiments, ACA process using ACA particle of diameter and density of 5${\mu}{\textrm}{m}$ and 4000 particles/$\textrm{mm}^2$ respectively shows optimum characteristic with the stabilzed bonding properties and contact resistance.

• Journal of the Korean Ceramic Society
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• v.12 no.1
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• pp.23-28
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• 1975

The object of this study is to find the optimum conditions for crystal growth and kinds of crystal in ZnO-Al2O3-SiO2 glass composition. At first, the base glass composed of ZnO (44.7%), Al2O3(14.0%) and SiO2(41.3%) was melted in propane gas furnace at 1450-150$0^{\circ}C$ for an hour, and then it was poured into the stainless steel mould heated previously at $600^{\circ}C$ to obtain the thin glass test piece. Four crystal forms from base glass such as stuffed keatite, zinc orthosilicate, zinc aluminosilicate, and cristobalite were crystallized during heat treatment between 80$0^{\circ}C$ and 110$0^{\circ}C$. For the investigation of crystal growth, X-ray diffractometer and thermal differential analysis were used and the growth rate of the four crystal forms were obtained by the method of Archimedes specific gravity and intensity comparison of X-ray diffraction peak. The results obtained were as follows. 1) Stuffed keatite peaks which started to appear after two hours at 80$0^{\circ}C$ were maximum after 11 hours and this crystal breaks down to willemite irreversibly at about 100$0^{\circ}C$. 2) Development of gahnite started at 85$0^{\circ}C$ and increased with temperature growth. 3) Stuffed keatite which had been transformed slowly into willemite at 100$0^{\circ}C$ was decreased with time and willemite increased until four hours. 4) Cristobalite began to be developed after treatment of 110$0^{\circ}C$.

• Journal of the Korean Society for Precision Engineering
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• v.34 no.3
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• pp.199-203
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• 2017

Hot embossing techniques are used to engrave patterns on plastic substrates. Roll based hot embossing uses a heated roll for a continuous process. A heated roll with relief patterns is impressed on a preheated plastic substrate. Then, the substrate is cooled down quickly to prevent thermal shrinkage. The roll speed is normally very slow to ensure substrate temperature increase up to the glass transition temperature. In this paper, we propose a noncontact preheating technique using focused infrared light. The infrared light is focused as a line beam on a plastic substrate using an elliptical mirror just before entering the hot embossing roll. The mid range infrared light efficiently raises the substrate temperature. For preliminary tests, substrate deformation and temperature changes were monitored according to substrate speed. The experiments show that the proposed technique is a good possibility for high speed hot embossing.