• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.10
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• pp.1107-1113
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• 2004

Dry film method for large size of PDP(Plasma Display Panel) module has been actively investigated. This method for lead-free transparent dielectric formation depends on green sheet technology. By adjusting the composition of transparent dielectric powders and organics, uniformly dispersed slurry was fabricated, Viscosity of the slurry exhibited pseudoplastic behavior for tape casting, Cast green sheets were tested under tensile condition at room temperature. It was found that the increase in transparent dielectric powder and binder ratio leads to decrease in strain to failure of green sheets from 120 % to 34 % and from 255 % to 4 %, respectively. Tensile strength of green sheets decreased abruptly with increase of transparent dielectric powder ratio, with minimum at 0.13 MPa. On the other hand, tensile strength increased continuously from 0.1 MPa to 2.4 MPa with increase of binder ratio. The green sheets were attached on the glass substrate and heated by following firing schedule. As a result, the best result was obtained when fired at 580 $^{\circ}C$ for 15 min and had transmittance of 78 % in visible range 550 nm.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.2
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• pp.468-474
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• 2017

A test service for the weapon systems evaluation is one of the most important processes during the weapon systems acquisition or development life cycle. Before completion of weapon systems development, the appropriate evaluation test can reduce risk and expense which might be expected during weapon systems development procedure. In this paper, it is suggested that a probabilistic prediction method based on Monte Carlo simulation for how much the annual weapon systems evaluation test excution ratio can be reached compared to the yearly initial planned test quantity. And then a weapon systems evaluation test quantitative management scheme is suggested to assist decision making for the test schedule manager who can arrange monthly test schedule based on the prediction result of annual test excution ratio. And the proposed method is applied for the weapon systems evaluation firing test data of the 8th directorate, Agency for Defense Development(ADD). And also the application result is examined.

• The Journal of Korean Academy of Prosthodontics
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• v.36 no.5
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• pp.772-785
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• 1998

This study was undertaken to clarify the microstructure of the different IPS Empress ingots by etching and to observe the change of leucite crystal structure according to subsequent heat treatment and the crystal distribution according to sprue types(${\phi}2.8mm$, single sprue; ${\phi}1.8mm$, double sprue) by scanning electron microscopy. IPS Empress T1, O1 ingots used for staining technique, and Dentin(A2) ingots used for layering technique were selected for this study. To observe the microstructures of these ingots before pressing, the specimens were prepared in splinters($3{\times}3{\times}3mm$) taken from the original ingots. And to estimate crystal distribution and microstructural change by sprue type and subsequent heat treatment. the specimens($3{\times}3{\times}3mm$) were heat-pressed through the two types of sprues with different diameters and numbers, and all specimens were fired according to the recommended firing schedule. The observed surface was ground with waterproof papers($#800{\sim}#1800$) on the grind polisher and was cleaned ultrasonically. All specimen were etched with 0.5% hydrofluoric acid. After etching, the surface was treated by ion sputter coating for SEM observation at an accelerating voltage of 20kV. In all specimens, the central area of ground surface was observed because there was less difference in microstructure between the peripheral area and the central area. The results were as follows ; 1. In the microstructure according to the ingot type, there was a wide difference between the staining (T1,O1) and layering(Dentin A2) ingots, but there was not a considerable difference between the T1 ingot and the O1 ingot for staining technique. 2. In all specimens, the crystal dispersion of IPS Empress ceramic using double sprue was significantly more scattered than that of IPS Empress ceramic using single sprue. The degree of scattering was strongest in the Dentin(A2) specimen and weakest in the O1 ingot. 3. In the microstructural change according to the subsequent heat treatment, all of ingots had some microcracks in the inside of the leucite crystal and the glass matrix after pressing. The inner splinters of the leucite crystal became smaller, and more microcracks occurred in the glass matrix due to increasing heat treatment times. 4. The size of leucite crystals varied from $1{\mu}m\;to\;5{\mu}m$. The mean size of mature crystals was about $5{\mu}m$. The form of the crystal was similar to a circle when it was smaller and similar to an ellipse when it was larger.