• 한국전산유체공학회:학술대회논문집
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• 2002.10a
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• pp.114-119
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• 2002

A numerical model is employed for design of a spinner device to dry the 5-th generation LCD glass panel. The turbulent flow in a spinner is driven by rotation of a large disk and suction by the exhaust system connected to vacuum chamber, which is simulated by using the FLUENT package. Based on numerical simulation, the required capacity of exhaust system is assessed. The effects of the presence of cover on the flow characteristics are examined. A computational trouble shooting is attempted to resolve the problem of panel rising which occurred in real experiments.

• Steel and Composite Structures
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• v.25 no.1
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• pp.93-104
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• 2017

In the present work, the effect of hygrothermal aging on the glass fibre and epoxy matrix interface has been investigated by destructive and non-destructive techniques. The glass fiber reinforced polymer (GFRP) composite laminates were prepared using Vacuum Assisted Resin Infusion Molding (VARIM) technique and the specimens were immersed in simulated seawater, followed by quantitative measurement. Besides this, the tensile tests of GFRP specimens revealed a general decrease in the properties with increasing aging time. Also, exposed specimens were characterized by a non-destructive ultrasonic guided Lamb wave propagation technique. The experimental results demonstrate a correlation between the drop in ultrasonic voltage amplitude and fall in tensile strength with increasing time of immersion. Hence, the comparison of the transmitted guided wave signal of healthy vis-a-vis specimens subjected to different extents of hygrothermal aging facilitated performance evaluation of GFRP composites.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1996.04b
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• pp.13-19
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• 1996

The tribological properties of the aluminum short fiber and glass fiber reinforced tin-bronze matrix composites manufactured by vacuum hot pressing was studied. The effect of the composition and the relative density on the wear properties was examined by a reciprocal type tribo-test machine. The results were discussed by the observation of the microstructure of sintered specimen and worn surface observation using SEM and EDS. Addition of the fibers led to the wear resistance since the metal matrix was reinforced by the fibers. The reinforcement of the fiber seemed to be stronger as the distribution of the fibers was more uniform. Graphite also reduce the wear loss. The pores in the sintered composites seemed to play an important role to improve the wear resistance since the pores provide the places where the solid lubricants locate.

• Korean Journal of Metals and Materials
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• v.49 no.8
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• pp.589-595
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• 2011

Laminated glass fiber-reinforced plastic (GFRP) composites were applied to an insulating structure of a magnet system for a nuclear fusion device. Decreased inter-laminar strength by a strong repulsive force between coils which is induced a problem of structural integrity in laminated GFRPs. Therefore, it is important to investigate the inter-laminar characteristics of laminated GFRP composites in order to assure more reliable design and better structural integrity. Three types of the laminated GFRP composites using a high voltage insulating materials were fabricated according to each molding process. To evaluate the grade of the fabricated composites, mechanical tests, such as hardness, tensile and compressive tests,were carried out. The autoclave molding composites satisfied almost of the mechanical properties reguested at the G10 class standard, but the vacuum impregnation (VPI) and Prepreg composites did not.

• Progress in Superconductivity and Cryogenics
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• v.11 no.2
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• pp.37-40
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• 2009

A mixed working fluid has a potential to widen the operation temperature range of the thermosiphon. In this study, the thermosiphon using $N_2\;and\;CF_4$ mixture as the working fluid is fabricated and tested to verify its transient thermo hydraulic characteristic. A transparent pyrex glass tube was used for the thermosiphon itself and the vacuum chamber was also fabricated by glass to visualize the internal state of thermo siphon. Onset of condensation temperature was related to the partial pressure of $CF_4$. Two solidifications were observed and condensate temperature range of mixed working fluid was from 160K to 70.7K with $N_2$ 25% composition.

• Journal of Ceramic Processing Research
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• v.21 no.2
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• pp.213-216
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• 2020

We investigated the optimal conditions for the manufacture of a rapid SiC heating element with increased durability for a flipchip bonder. In the moulding step prior to the sintering of the SiC heating element, a pressure of either 25 or 125 MPa wasapplied by uniaxial pressing to control the micropores; this was aimed at improving the resistance of the ultimate specimen. The moulded specimen was sintered by using a vacuum furnace with silicon as a sintering additive. The measurement of thehot modulus of rupture (HMOR) of the resulting SiC sintered body revealed that the HMOR was high. In addition, a methodfor protecting the heating element from the external environment was developed. A glassy coating layer was deposited on thesurface of the structure to improve the corrosion resistance of the sintered body; further, the performance of the coating layerwas verified through a neutral and acidic salt spray test. Finally, we established the optimal process conditions formanufacturing a rapid SiC heating element with improved corrosion resistance.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1946-1949
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• 1996

We have performed silicon-to-silicon anodic bonding using glass layer deposited by electron beam evaporation. Wafers can be bonded at $135^{\circ}C$ with an applied voltage of $35V_{DC}$, which enables application of this technique to the vacuum packaging of microelectronic devices, because its bonding temperature and voltage are low. From the experimental results, we have found that the evaporated glass layer more than $1\;{\mu}$ m thick was suitable for anodic bonding. The role of sodium ions for anodic bonding was also investigated by theoretical bonding mechanism and experimental inspection.

• Journal of the Korean Society for Heat Treatment
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• v.12 no.3
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• pp.199-205
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• 1999

The quaternary Ti-Al-V-N films have been grown on glass substrates by reactive dc and rf magnetron sputter deposition from a Ti-6Al-4V target in mixed Ar-$N_2$ discharges. The Ti-Al-V-N films were investigated by means of X-ray diffraction(XRD), electron probe microanalysis(EPMA) and scratch tester. Both XRD and EPMA results indicated that the Ti-Al-V-N films were of single B1 NaCl phase having columnar structure with the (111) preferred orientation. Scratch tester results showed that the adhesion strength of Ti-Al-V-N films which treated with substrate heating and vacuum annealing was superior to that of as-deposited film. The good adhesion strength was also achieved in the double-layer structure of Ti-Al-V-N/Ti-Al-V/Glass.

• Journal of the Korean Ceramic Society
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• v.43 no.10 s.293
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• pp.607-612
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• 2006

In VARTM (Vacuum Assisted Resin Transfer Molding) process, the permeability generally controls the filling time of the resin and it also affects the void characteristics of the fiber composite. In this study, carbon and glass fiber inter-layered hybrid composites (carbon fiber centered stack) with an epoxy matrix were fabricated by VARTM process and evaluated the resin flow and macro void characteristics. The permeability of glass fiber was higher than that of carbon fiber used in this study. Using Darcy's equation, the permeability of hybrid composites could be predicted and experimentally confirmed. After curing, the macro void content of hybrid composites was investigated using image analyzer. The calculated filling time was well agreed with experimental result and the void content was significantly changed in hybrid composites.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.10
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• pp.871-877
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• 1998

Electroluminescent(EL) devices based on organic materials have been of great interest due to their possible applications for large-area flat-panel displays, where they are attractive because of their capability of multicolor emission, and low operation voltage. In this study, glass substrate/ITO/Eu(TTA)$_3$(phen)/Al, glass substrate/ITO/Eu(TTA)$_3$(phen)/Al and glass substrate/ITO/Eu(TTA)$_3$(phen)/AlQ$_3$/Al structures were fabricated by vacuum evaporation method, where aromatic diamine(TPD) was used as a hole transporting material, Eu(TTA)$_3$(phen) as an emitting material, and Tris(8-hydroxyquinoline) aluminu-m(AlQ$_3$) as an electron transporting layer. Electrolumescent(EL) and I-V characteristics of Eu(TTA)$_3$-(-phen) were investigated. These structures show the red EL spectra, which are almost the same at the PL spectrum of Eu(TTA)$_3$(phen). I-V characteristics of this structure show that turn-on voltage was 9V and current density was 0.01A/㎤ at a operation voltage of 9V. Electrical transporting phenomena of these structures were explained using the trapped-charge-limited current model with I-V characteristics.