• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.11a
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• pp.21-22
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• 2023

In order to manufacture high-quality free-form concrete panel (FCP), it is necessary to analyze the limitations of free-form silicone mold (FSM) and conduct technology development research. Currently, the FSM used in FCP manufacture is classified into a side silicon mold(SSM) and a lower silicon mold(LSM). In this study, the limitations of each silicon mold were analyzed and solutions were proposed. In the case of side silicon mold, there is a limit to cannot supporting the side pressure of concrete. Therefore, a mold stacking method was proposed, and at the same time, a process of correcting the movement value of the rod was proposed. In the case of the lower silicon mold, there is a limit to completely implementing the design shape. Therefore, a real-time scanning method and a process of displaying FCP shape coordinates were proposed. The results of this study are expected to be used as basic data for manufacturing high-quality FCP.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.20-23
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• 2001

Plasma Display Panel(PDP) is a type of flat panel display utilizing the light emission produced by gas discharge. Barrier Ribs of PDP separating each sub-pixel prevents optical and electrical crosstalks from adjacent sub-pixels. The mold for forming the barrier ribs has been newly researched to overcome the disadvantages of conventional manufacturing processes such as screen printing, sand-blasting and photosensitive glass methods. The mold for PDP barrier ribs have stripes of micro grooves transferring glass-material wall. In this paper, Stripes of grooves of which width 48${\mu}{\textrm}{m}$, depth 124$\mu\textrm{m}$ , pitch 274$\mu\textrm{m}$ was acquired by machining of single crystal silicon with dicing saw blade. Maximum roughness of the bottom of the grooves was 59.6nm Ra in grooving Si. Barrier ribs were formed with silicone rubber mold, which is transferred from grooved Si forming hard mold. Silicone rubber mold has the elasticity, which enable to accommodate the waveness of lower glass plate of PDP. The methods assisted by the microwave and UV was adopted for reducing the forming time of glass paste.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.5
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• pp.171-176
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• 2001

Plasma Display Panel(PDP) is a type of flat panel display utilizing the light emission produced by gas discharge. Barrier Ribs of PDP separating each sub-pixel prevents optical and electrical crosstalks from adjacent sub-pixels. Mold for forming barrier ribs has been newly researched to overcome the disadvantages of conventional manufacturing process such as screen printing, sand-blasting and photosensitive glass methods. Mold for PDP barrier ribs have stripes of micro grooves transferring glass-material wall. In this paper, Stripes of grooves of which width 48${\mu}{\textrm}{m}$ and 270${\mu}{\textrm}{m}$, depth 124${\mu}{\textrm}{m}$, pitch 274${\mu}{\textrm}{m}$ was acquired by machining hard and brittle materials of WC, Silicon, Alumina with dicing saw blade. Maximum roughness of the bottom and sidewall of the grooves was respectively 120nm, 287nm in grooving WC. Maximum tilt angle caused by difference between upper-most width and lower-most width was 2$^{\circ}$. Maximum Radius of bottom curvatures was 7.75${\mu}{\textrm}{m}$. This results satisfies the specification for barrier ribs of 50 inch XGA PDP if the groove form of mold was fully transferred to the barrier ribs. Barrier ribs were formed with Silicone rubber mold, which is transferred from grooved hard materials. Silicone rubber mold has elasticity accommodating the waveness of lower glass plate of PDP.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.6
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• pp.176-183
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• 2002

Plasma Display Panel(PDP) is a type of flat panel display utilizing the light emission produced by gas discharge. Barrier Ribs of PDP separating each sub-pixel prevents optical and electrical crosstalks from adjacent sub-pixels. The mold for forming the barrier ribs has been newly researched to overcome the disadvantages of conventional manufacturing processes such as screen printing, sand-blasting and photosensitive glass methods. The mold for PDP barrier ribs have stripes of micro grooves transferring glass-material wall. In this paper , Stripes of grooves of which width 48$\mu$m, depth 124$\mu$m , pitch 274$\mu$m was acquired by machining of single crystal silicon with dicing saw blade. Maximum roughness of the bottom of the grooves was 59.6 nm Ra in grooving Si. Barrier ribs were farmed with silicone rubber mold, which is transferred from grooved Si forming hard mold. Silicone rubber mold has the elasticity, which enable to accommodate the waviness of lower glass plate of PDP. The methods assisted by the microwave and UV was adopted for reducing the forming time of glass paste.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.3
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• pp.261-270
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• 2013

Purpose: Adsorption properties of lysozyme and albumin according to physiochemical properties of commercial contact lens classified with the FDA categories and a contact lens fabricated in the laboratory were investigated. Methods: The contact lens were prepared using HEMA(2-hydroxyethyl methacrylate) and TRIM(3-(trimethoxysilyl) propyl methacrylate) in a cast mold. Artificial tears containing lysozyme and albumin were prepared. We measured the amounts of protein adsorbed on the each lenses with varying adsorbed time (48 hour) and the pH range (6, 6.8, 7.4, 8.2, 9) of artificial tear. Amount of the proteins absorbed on the contact lenses were measured by using HPLC. Results: Time to reach the equilibrium of protein adsorption for silicone hydrogel lens was taken longer than hydrogel lens. The amount of adsorbed both lysozyme and albumin at equilibrium were greater for the hydrogel lens than the silicone hydrogel lens, and larger for the ionic lens than the non-ionic lens. Lysozyme was more adsorbed on the higher water content of contact lens, whereas albumin was more adsorbed on the lower water content of contact lens. Only lysozyme was adsorbed on the Group IV hydrogel lens of ionic higher water content. The adsorption of protein on contact lens increased with pH of artificial tears as close to the isoelectric point of each protein. Conclusions: The adsorption amount of lysozyme is more affected by the ionic strength of the contact lens surface than the water content of contact lens. Albumin adsorption is more affected by water content than the ionic strength of the contact lens surface. For the adsorption of proteins on the silicone hydrogel lens, the pore size, determined both by the number of Si atoms and the chemical structure of the silicone-containing monomers, as well as the polarity of contact lens should be also considered.

• Journal of Technologic Dentistry
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• v.40 no.1
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• pp.33-40
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• 2018

Purpose: The purpose of this study was to investigate the influence of mechanical properties of various ultra-dental stone by setting methods. Methods: 240 cylinder specimens($10mm{\times}20mm$) were prepared from three ultra-dental stones(Gemma, Die keen and Fuji rock; n = 80) in accordance with the manufacturers' recommendations. Half of the specimens of each stone(n = 40) were dried in open air within a room temperature; the other half(n = 40) underwent in a silicone rubber mold in open air for 30 minutes and then were dried in a microwave oven for 10 minutes to 600W. Compressive strength(CS), compressive modulus(CM) and diametral tensile strength(DTS) conducted until fracture using Instron 5966 at each of the following periods: 1 and 24 hours from mixing. One-way analysis of variance and Scheffe's post hoc test were performed for statistical comparisons at a significance level of P<.05. Results: The CS and CM values in all dental stone indicated highest after 24h(54.25 MPa < ) than the values for specimens dried in microwave method. The DTS values revealed the highest microwave method. However, in 24h, FJ(Fu-ji rock) and GM(Gemma) had lower mechanical properties than air. Conclusion : Within the limitations of this study, CS did not influence by microwave method but DTS affected according to the setting.

• Restorative Dentistry and Endodontics
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• v.22 no.1
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• pp.396-412
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• 1997

The purpose of this study is to observe the corrosion characteristics of five dental amalgams(CAULK FINE CUT, OPTALLOY II, DISPERSALLOY, TYTIN, and VALIANT) in the solutions with fluoride compound through the anodic polarization curve obtained by using a potentiostat. After each amalgam alloy and Hg being triturated, the triturated mass was inserted into the cylindrical metal mold, and condensed by hydraulic pressure(160 kg/$cm^2$). Each specimen was removed from the metal mold. Specimens were polished with the silicone carbide grinding paper 24 hours after condensation and stored at room temperature for 1 week. The anodic polarization curves were employed to compare the corrosion behaviours of the amalgams in 0.9 % saline solution and in the saline solutions with 2.2 ppm, 0.05 %, 2 % NaF, and 8 % $SnF_2$ at $37^{\circ}C$ with 3-electrode potentiostat. After the immersion of specimen in electrolyte for 30 minutes, the potential scan was begun. The potential scan range was -1500m V to + 800m V(vs. S.C.E.) in the working electrode and the scan rate was 50 mV/sec. The results were as follows, 1. The corrosion potential, the potential of anodic current peak, and transpassive potential in the saline solutions with NaF shifted to lower direction than those in normal saline solution, and the current density in the saline solutions with NaF was higher than that in normal saline solution. The differences were increased as the concentrations of NaF became higher. 2. The corrosion potential and transpassive potential in the saline solution with $SnF_2$ shifted to higher direction than those in normal saline solution, and the current density in the saline solution with $SnF_2$ was higher than that in normal saline solution after the corrosion potential. The anodic polarization curves in the saline solution with $SnF_2$ had no outstanding anodic current peak. 3. The corrosion potentials for high-copper amalgams were much higher than those for CAULK FINE CUT and OPTALLOY II in normal saline solution, but, as the concentrations of fluoride compound became higher, the differences in corrosion potentials between them were decreased. The corrosion potentials had the similarity in the saline solution with 2% NaF or 8% $SnF_2$. 4. The current density for TYTIN was the lowest among the others in normal saline solution and in the saline solution with 2.2 ppm or 0.05 % NaF. 5. There was no significant difference in current density between Pd-enriched VALIANT and other high-copper amalgams.

• The Journal of Korean Academy of Prosthodontics
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• v.61 no.3
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• pp.189-197
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• 2023

Purpose. This study aimed to compare and evaluate the shear bond strength between various temporary prostheses resin blocks fabricated by subtractive and additive manufacturing methods bonded to self-curing reline resin. Materials and methods. The experimental groups were divided into 4 groups according to the manufacturing methods of the resin block specimens and each specimen was fabricated by subtractive manufacturing (SM), additive manufacturing stereolithography apparatus manufacturing (AMS), additive manufacturing digital light processing manufacturing (AMD) and conventional self-curing (CON). To bond the resin block specimens and self-curing resin, the reline resin was injected and polymerized into the same location of each resin block using a silicone mold. The shear bond strength was measured using a universal testing machine, and the surface of the adhesive interface was examined by scanning electron microscopy. To compare between groups, one-way ANOVA was done followed by Tukey post hoc test (α = 0.05). Results. The shear bond strength showed higher values in the order of CON, SM, AMS, and AMD group. There were significant differences between CON and AMS groups, as well as between CON and AMD groups. but there were no significant differences between CON and SM groups (P > .05). There were significant differences between SM and AMD groups, but there were no significant differences between SM and AMS groups. The AMS group was significantly different from the AMD group (P < .001). The most frequent failure mode was mixed failures in CON and AMS groups, and adhesive failures in SM and AMD groups. Conclusion. The shear bond strength of SM group showed lower but not significant bond strength compared to the CON group. The additive manufacturing method groups (AMS and AMD) showed significantly lower bond strength than the CON group, with the AMD group the lowest. There was also a significant difference between the AMD and SM group.