• The Journal of Korean Academy of Prosthodontics
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• v.34 no.2
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• pp.246-265
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• 1996

After adjusting glazed surface of laminate veneer porcelain by reduction in the clinical procedure, an additional polishing procedure is required to smoothen the roughened surface by reduction, as it is difficult to glaze it again in the furnace. In this study, four kinds of laminate veneer porcelain were ground with diamond points as done in the clinical procedure. The adjusted porcelain surface was polished with Durawhite stone, Ceramiste points, Exa cerapol, Porcelain polishing wheel, Diamond polishing paste. The degree of surface roughness was evaluated with SEM and profilometer at each step, The self glazed surface and the glazed surface with glazing powder were compared with the polished surface and surface roughness of four kinds of laminate veneer porcelain according to the polishing method and step were obserbed. The following results were obtained : 1. There was no difference in the average surface roughness Ra value and the surface roughness obserbed under SEM according to the polishing methods and steps used, among the four kinds of laminate veneer porcelain including Colorlogic, Exelco, Vintage, and Vitadur alpha product. 2. Due to porosities, the surface in the course of polishing by polishing instruments was rougher than the glazed surface, evaluated with a SEM. 3. Insta-Glaze diamond polishing paste has no statistical difference with self glazed group 1, although it has a lower value in average surface roughness Ra value. 4. Group 2 which was glazed with galzing powder was lowest in view of SEM, but it revealed higher surface roughness Ra value than group 1, the glazed surface and group 8, polished by diamond polishing paste, due to surface waveness. 5. Proper surface smoothness could not be in the surface roughness analysis of SEM and profilometer by Shofu laminate polishing kit composed of Diamond point, Durawhite stone and Ceramiste points. Based on the results of this study, the following conclusions can be drawn. We obtain low surface roughness than glazed surface by polishing instruments, but not perfect results clinically. In order to obtain a perfect clinical result or a surface smoothness comparable to glazed porcelain there is a need for further improvement of porcelain materials, condensa-tion techniques, polishing instruments and polishing methods. Furthermore card should be taken not to breakdown the glazed surface during the clinical and laboratory procedure.

• Journal of the Korean Solar Energy Society
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• v.34 no.5
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• pp.1-9
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• 2014

Daylight is very useful to control the indoor environment, and can save energy in buildings. So it is necessary to evaluate the daylighting performance of buildings. We proposed a simplified equation that can be used in the early stages of design. And we verified the equation by using the measured illuminance data from the 1/5 scale model. We compared the calculated indoor illuminances and measured illuminance including Daylight Factors of scale model in order to verify the applicability of the simplified equation, and proved the analyzed values are acceptable. When we have a target value of the Daylight Factor, we just have to determine the window area, transmittance of the glazing system, and indoor surface reflectance, then can achieve it with this simplified equation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.507-513
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• 1998

In surface grinding, the conditions of the grinding wheel has much more significant effect on the machined workpiece as compared to other metal removal processes. The contact between the grinding wheel and the workpiece introduce heat and resistance, which restrict the self-dressing of the grits and result in burrs cracks on the workpiece. Therefore, before or during the grinding operation, it is necessary to self-dressing the grinding wheel for more accurate performance. In general, however, the choice of the dressing time has made by the operator's own decision or the condition of the workpiece. In this paper, a new method for finding the optimal dressing time of the grinding wheel is proposed. In order to develop a more sophisticated methodology, a non-contacting in-process optical measurement method using a laser beam has been introduced to find the glazing, loading, and spilling of the grinding wheel Simultaneously, a three-dimensional computer simulation of the grinding operation has been attempted based on the contact mechanism between the grinding wheel and the workpiece. The grains of the grinding wheel are simulated and the optimal dressing time is determined based on the amount of grain wear and work surface roughness.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.247-251
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• 2004

Chemical-Mechanical Polishing(CMP) especially is becoming one of the most important ULSI processes for the 0.25m generation and beyond. And there are many elements affecting CMP performance such as slurry, pad, process parameters and pad conditioning. Among these elements the CMP pad is considered one of the most important because of its change. But the surface of the pad has irregular pores, so there is non-uniformity of slurry flow and of contact area between wafer and the pad, and glazing occurs on the surface of the pad. So we make CMP pad with micro structure using micro molding method. This paper introduces the basic concept and fabrication technique of CMP pad with micro-structure and the characteristic of polishing. Experimental results demonstrate the removal rate, uniformity, and time vs. removal rate.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.1075-1080
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• 2006

Purpose of this study is proposal of estimating method about window thermal performance that based on KS F 2278 'Test method of thermal resistance for windows and doors' due to material composition of PVC frame window. First step of this study is research of present state about material composition of PVC frame window. Second is selection of main effective elements about window thermal resistance. For example, composition of Glazing, Frame area ratio of total window area, frame width, opening type, area of heat transfer and so on. Third is multiple regression analysis about thermal performance of PVC frame window due to main effective elements. It produces equations of multiple regression analysis due to opening type. Case of sliding window is $Y=0.149+0.034X_g+0.248X_{far}$, 4track sliding is $Y=0.584+0.175X_g+1.355X_{far}-0.008X_{fw}$, Tilt & Turn window is $Y=-0.161+0.076X_g+0.576X_{far}+0.0008X_{fw}$.

• Journal of Dental Rehabilitation and Applied Science
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• v.37 no.4
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• pp.177-185
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• 2021

Clinical applications of translucent zirconia as well as traditional zirconia (3 mol% yttria stabilized tetragonal zirconia polycrystal, 3Y-TZP) are increasing. For this reason, studies on factors affecting the optical properties of dental zirconia have been continuously reported. The optical effect of dental zirconia may vary depending on the yttria content, the thickness of the prosthesis, the sintering process, polishing, glazing and cementation in laboratory and clinical procedures. Increasing the yttria concentration can reduce the masking effect. Translucency decreases as the thickness of the restoration increases, but the required thickness may vary depending on the properties of the zirconia block. The high-speed sintering method can shorten the manufacturing time, but in some cases, the translucency of the prosthesis may decrease. In addition, the optical properties can be affected by the surface roughness of zirconia and the polishing process. The use of an appropriate colored cement can help with the masking effect of zirconia and can be useful for color matching for more esthetic results.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.410.1-410.1
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• 2016

Vanadium dioxide ($VO_2$) is a well-known material that exhibits a metal-semiconductor transition at 340 K, with drastic change of transmittance at NIR region. However, $VO_2$ based thermochromics accompany with low visible transmittance value and unfavorable color (brownish yellow). Herein, we demonstrate the adjustment of visible transmittance of $VO_2$ thin film by nanosphere template assisted patterning process using sol-gel method. 2-Dimenstional honeycomb shape was varied as function of diameter of nanosphere and coating conditions. The morphological geometry of the films was investigated by FE-SEM and AFM. Result shows that inversed shape of nanosphere was formed clearly and pattern width was altered according to the bead size. This structure creates the geometrical blank area from the position of nanosphere which improves the optical transmittance at the visible region. Moreover, such patterned $VO_2$ thin film not only maintains the optical switching efficiency, but also generate the gorgeous scattering effect which presumably support the glazing application.

• Journal of the Korean housing association
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• v.13 no.2
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• pp.73-78
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• 2002

Recently, the energy consumption has been sharply increased and the environmental pollution has been serious, resulted in increased use of fossil fuel. These facts are applied to most fields, and are especially important issues in the field of architecture. The energy consumption rate of building is about 30% of all energy consumption, and the rate of residential is about 20% of the rate of building and is increasing gradually. The purpose of this article is firstly to analyse an actual energy consumption rate of model building and compare it with alternative methods, which are applied passive system to, and secondly to suggest an optimal passive method for saving energy. The conclusion of this study is as follows; 1) As compared with the existing house on actual energy consumption rate, 6% in changing orientation to a south, 9% in using double low-e glazing and 23% in shading is decreased. 2) The change of insulation from 50 to 100mm did not show dramatical difference in energy consumption rate. 3) As changed indoor temperature at 2$0^{\circ}C$ in winter and 27$^{\circ}C$ in summer, the rate shows a reduction of 14% compared with the existing condition.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.434-437
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• 2005

Chemical Mechanical Polishing (CMP) has become an essential step in the overall semiconductor wafer fabrication technology. In general, CMP is a surface planarization method in which a silicon wafer is rotated against a polishing pad in the presence of slurry under pressure. The polishing pad, generally a polyurethane-based material, consists of polymeric foam cell walls, which aid in removal of the reaction products at the wafer interface. It has been found that the material removal rate of any polishing pad decreases due to the so-called 'pad glazing' after several wafer lots have been processed. Therefore, the pad restoration and conditioning has become essential in CMP processes to keep the urethane polishing pad at the proper friction coefficient and to allow effective slurry transport to the wafer surface. Diamond pad conditioner employs a single layer of brazed bonded diamond crystals. Due to the corrosive nature of the polishing slurry required in low pH metal CMP such as copper, it is essential to minimize the possibility of chemical interaction between very low pH slurry (pH <2) and the bond alloy. In this paper, we report an exceptional protective coated conditioner for in-situ pad conditioning in low pH Cu CMP process. The protective Cr-coated conditioner has been tested in slurry with pH levels as low as 1.5 without bond degradation.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.2
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• pp.191-199
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• 2005

Double pane window system, in which an air layer with a finite width is filled between glasses, is used in order to increase the insulation efficiency. In the present study, a conjugate heat transfer problem of a double pane window system has been studied numerically in order to investigate the effect of an air layer on the heat transmittance of the double pane window system using a finite element method based on P2P1 basis function. In this study on the conjugate heat transfer of a double pane window system, numerically predicted Nusselt numbers with or without conjugate heat transfer effect have been compared with an available existing empirical formula. It has been found that a Nusselt number from an existing formula for an enclosed space is different from that obtained from the present conjugate heat transfer analysis mainly due to the effects of a very high aspect ratio and conjugate heat transfer mechanism. Furthermore, it has been shown that the numerically estimated optimal air thickness of the double pane window system with conjugate heat transfer effect is a little bit longer than that obtained without considering conjugate heat transfer effect.