• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.11
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• pp.977-982
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• 2007

The realization of the photoresist(PR) removal method with vaporized water and ozone gas mixture has been studied for the LCD TFT array manufacturing. The developed PR stripper uses the water boundary layer control method based on the high concentration ozone production technology. We develop the prototype of PR stripper and experiment to find the optimal process parameter condition like as the ozone gas flow/concentration, process reaction time and thin boundary layer formation. As a results, we realize the LCD PR strip rate over the 0.4 ${\mu}m/min$ and this PR removal rate is more than 5 times higher than the conventional immersion type ozonized water process.

• Restorative Dentistry and Endodontics
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• v.27 no.5
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• pp.521-529
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• 2002

The purpose of this study was to compare the shaping time of two shaping methods and the leakage of three different obturation techniques. Ninty three canaled human molar teeth were used, which were randomly divided into two groups of forty teeth each and ten control teeth. After working length determination, the one group was prepared crown-down technique using rotary root canal instruments of GT rotary files .12/20, .10/20, .08/20 and .06/20 taper(Maillefer Instrument SA. Switzerland). The other group was instrumented with Gates Glidden burs(#1, #2, and #3) to coronal preparation and GT rotary files .08/20 and .06/30 taper to apical preparation. Shaping time was measured. After root canals were instrumented, they were divided to three subgroups and obturated as follows : Subgroup 1, obturated with single cone method Subgroup 2, obturated with lateral condensation : Subgroup 3, obturated with continuous wave technique. Three subgroups were obturated using non-standardized gutta-percha cone(Diadent, Korea, .06 or .08 taper) and AH-26(Dentsply DeTrey, Germany) as a root canal cement. Ten unobturated teeth served as positive and negative controls. After immersion in 2% methylene blue solution for 1 month, the teeth were washed during 24h. The teeth were demineralized in 10% nitric acid and dehydrated by immersion in 80, 90 and 100% ethyl alcohol. The teeth were finally cleared and stored in 100% methylsalicylate, and apical dye penetration was evaluated under stereomicroscope(Leica M420, LC, U.S.A)at $\times$8.75 magnification. Liner measurement of dye penetration was assessed with the use of digitalized image analysing system (analySIS, GmbH, Germany) The data were analysed statistically using independent T-test and Two-way ANOVA and Tukey test. The result were as follows 1. In canal prepared with GT$^{TM}$ rotary file, shaphing time taked more than the group of using Gates Glidden drill to coronal preparation without statistical significance (p>0.05) 2. The group of single cone obturation using canal preparation of GT$^{TM}$ rotary files showed significantly more apical leakage than those of lateral condensation and continuous wave technique regardless of shaping method (p<0.05). 3 The group of single cone obturation using canal preparation of GT$^{TM}$ rotary files and Gates Glidden drill showed significantly more apical leakage than those of continuous wave technique regardless of shaping method (p<0.05). 4. Regardless of shaping method, The group of continuous wave obturation showed less apical leakage than those of lateral condensation without statistical significance (p>0.05). 5. The group of single cone obturation using canal preparation of GT$^{TM}$ rotary files and Gates Glidden drill showed more apical leakage than the group of lateral condensation using same shaping method with-out statistical significance (p＞0.05).

• International Journal of Naval Architecture and Ocean Engineering
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• v.7 no.1
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• pp.142-156
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• 2015

A new method for ship Inner Shell optimization, which is called Parametric Inner Shell Optimization Method (PISOM), is presented in this paper in order to improve both hull performance and design efficiency of transport ship. The foundation of PISOM is the parametric Inner Shell Plate (ISP) model, which is a fully-associative model driven by dimensions. A method to create parametric ISP model is proposed, including geometric primitives, geometric constraints, geometric constraint solving etc. The standard optimization procedure of ship ISP optimization based on parametric ISP model is put forward, and an efficient optimization approach for typical transport ship is developed based on this procedure. This approach takes the section area of ISP and the other dominant parameters as variables, while all the design requirements such as propeller immersion, fore bottom wave slap, bridge visibility, longitudinal strength etc, are made constraints. The optimization objective is maximum volume of cargo oil tanker/cargo hold, and the genetic algorithm is used to solve this optimization model. This method is applied to the optimization of a product oil tanker and a bulk carrier, and it is proved to be effective, highly efficient, and engineering practical.

• Design & Manufacturing
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• v.16 no.2
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• pp.46-52
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• 2022

As the consumer market in the eco-friendly vehicle industry grows, the demand for water pump in a electric car parts market. This study intend to propose a mathematical model that can verify the effect of improving thermal properties when a non-conductive cooling filler liquid is introduced into an electric vehicle water pump. Also, the pros and cons of the immersion cooling method and future development way were suggested by analyzing the cooling characteristics using on the derived analysis solution. Thermal characteristics analysis of electric water pump applied with non-conductive filler liquid was carried out, and the diffusion boundary condition in the motor body and the boundary condition the inside pump were expressed as a geometric model. As a result of analyzing the temperature change for the heat source of the natural convection method and the heat conduction method, the natural convection method has difficulty in dissipating heat because no decrease in temperature due to heat release was found even after 300 sec. Also, it can be seen that the heat dissipation effect was obtained even though the non-conductive filling liquid was applied at the 120 sec and 180 sec in the heat conduction method. It has proposed to minimize thermal embrittlement and lower motor torque by injecting a non-conductive filler liquid into the motor body and designing a partition wall thickness of 2.5 mm or less.

• The Journal of the Korea Contents Association
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• v.10 no.9
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• pp.410-420
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• 2010

The purpose of this study was to identify organizational effectiveness and organizational commitment according to participation satisfaction in leisure sports activities of police organization. To do this, the researcher selected five police stations using convenience sampling method targeting the police officers who participated in leisure sports activities among those police officers who were working in Gwangju Metropolitan City as of 2009. And as for the subjects of this study, total 200 police officers were sampled. Excluding 27 responses which were insincerely answered or not returned, 173 questionnaires were used for final analysis. The results were made as follows. First, the results from analysis revealed that contribution to public goods, social recognition, and individual accomplishment, which are sub variables of participation satisfaction, had influences on both job satisfaction and organization immersion which are sub variables of organization effectiveness. Second, results from analysis showed that value commitment and continuance commitment which are sub variables of organizational commitment were affected by contribution to public goods social recognition and public goods individual accomplishment, respectively. Third, the results from analysis revealed that both job satisfaction and organization immersion which are sub variables of organizational effectiveness affected value contribution, and that, only organization immersion had an influence on the continuance commitment.

• Composites Research
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• v.30 no.1
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• pp.71-76
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• 2017

The purpose of this study was to predict the long-term performance using the interlaminar shear strength of carbon fiber/epoxy composites exposed to environmental factors. Interlaminar shear specimens, manufactured by the filament winding method, were exposed to the conditions of drying at $50^{\circ}C$, $70^{\circ}C$, and $100^{\circ}C$ and of immersion at $25^{\circ}C$, $50^{\circ}C$, and $70^{\circ}C$ for up to 3000 hours, respectively. According to the results, the interlaminar shear strength did not vary significantly with the exposure time for the drying at $50^{\circ}C$ and $70^{\circ}C$, but it increased somewhat for the drying at $100^{\circ}C$ due to the post curing as the exposure time increased. The interlaminar shear strength of the specimens exposed to the immersion at $25^{\circ}C$ did not change significantly at the beginning of exposure, but it decreased with the exposure time and the degree of decrease increased as the environmental temperature increased. The linear regression equations for the environmental temperatures were obtained from the interlaminar shear strength of the specimens exposed to the immersion for up to 3000 hours. Using these linear regression equations, the interlaminar shear strength was estimated to be within 5.5% of the measured value at $25^{\circ}C$ and $50^{\circ}C$, and 2.3% of the measured value at $70^{\circ}C$. Therefore, the proposed performance prediction procedures can predict well the long-term interlaminar shear strength of carbon fiber/epoxy composites exposed to environmental factors.

• Journal of Biomedical Engineering Research
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• v.17 no.3
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• pp.327-336
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• 1996

This study was performed to investigate the effec% of immersion in water and thermal cycling on the mechanical peoperties of light cured restorative composite resins. Five commerically available light-cured composite resins(Photo Clearfil A : CA, Lite-Fil A . LF, Clearril Photo Posterior CP, Prisms AP.H.. PA, 2100 : ZH) were unto The specimens of 12 m in diameter and 0.7 m in thickness were made, and an immersion in $37^{\circ}C$ water for 7 days and a thermal cycling of 1000 cycles at 15 second dwell time each in $5^{\circ}C$ and $55^{\circ}C$ baths were performed. Biaxial flexure test was conducted using the ball-on-three-ball method at the crosshead speed of 0.5mm/min. In order to investigate the deterioration of composite resins during the thermal cycling test, Weibull analysis for the biaxial flexure strengths was done. Fracture surfaces and the surfaces before and after the thermal cycling test were examined by SEM. The highest Weibull modulus value of 10.09 after thermal cycling tests which means the lowest strength variation, was observed in the CP group, and the lowest value of 4.47 was obsered in the LF Group. Biaxial flexure strengths and Knoop hardness numbers significantly decreased due to the thermal cycling ($\textit{p}$< 0.01), however, they recovered when specimens were drie4 The highest biaxial flexure strength of 125.65MPa was observed in the ZH group after the thermal cycling test, and the lowest value of 64.86MPa was observed in the CA group. Biaxial flexure strengths of ZH and CP groups were higher than those of PA, CF, and CA groups after thermal cycling test($\textit{p}$< 0.05). Knoop hardness numbers of CP group after the thermal cycling test was the highest(95.47 $\pm$ 7.35kg/$mm^2$) among the samples, while that of CA group was the lowest(30.73 $\pm$ 2.58kg/$mm^2$). Knoop hardness numbers showed the significant differences between the CP group and others after the thermal cycling test(($\textit{p}$< 0.05). Fracture surfaces showed that the composite resin failure developed along the matrix resin and the filler/resin interface region, and the cracks propagated in the conical shape from the maximum tensile stress zone.

• The Journal of Korean Academy of Prosthodontics
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• v.41 no.2
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• pp.136-147
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• 2003

Statement of problem : Ceramic and composite resin have been used to fulfill the demand for esthetic prosthesis. However, ceramic is easy to break and wears off the opposite natural teeth. Conventional composite resin also has low abrasive resistance and color stability. Ceramic Optimized Polymer (ceromer) was developed in mid-1990s to overcome the shortfalls of ceramic and composite resin. Ceromer has similar abrasiveness with the natural tooth and has relatively high strength. Color stability affects esthetics and long-term prognosis of the prosthesis. Purpose The purpose of this study was to compare color stability of ceromers(2 types : $Artglass^{(R)}$. $Targis^{(R)}$) with ceramics ($Vintage^{(R)}$-polishing, $Vintage^{(R)}$-glazing). Material and Method : The color difference(${\Delta}E^*$) was measured by spectrophotometer with different immersion time. Twenty disks, 3mm in thickness and 10mm in diameter, were fabricated for each specimen in shade A2(Vita Lumin shade guide), Specimens (5 samples in each group) were immersed in the food colorants (Red no.3. Yellow no.4, Blue no.1, Distilled water) for 24 hours, 48 hours and 72 hours respectively. $L^*,\;a^*$ and $b^*$ value were measured with spectrophotometer (CM 503i : Minolta Co., Japan) and mean ${\Delta}E^*$ value was calculated for statistical analysis Results : The results of this study were obtained as follows. 1. The ${\Delta}E^*$ values of all test samples increased with the time of immersion. 2. The ${\Delta}E^*$ values of all materials increased in order of Distilled Water, Yellow no.4, Blue no.1 and fed no.3. There was significant difference between Red no.3 and the other food colorants(p<0.05). 3. The ${\Delta}E^*$ values increased in order of $Vintage^{(R)}$-glazing, $Vintage^{(R)}$-polishing. $Artglass^{(R)}$ and $Targis^{(R)}$. There was significant difference between $Vintage^{(R)}$-glazing and the other materials (p<0.05). Conclusion : By means of the above results, immersion time was found to be a critical factor for color stability of ceromer. For the long-term color stability of prosthesis it is recommended patients having ceromer prosthesis ($Artglass^{(R)},\;Targis^{(R)}$) to reduce the habitual intake of Red no.3 colorants con taming foods.

• Korean Journal of Food Science and Technology
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• v.31 no.6
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• pp.1511-1517
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• 1999

Effects of washing methods using electrolyzed acid water on lettuce(Lactuca sativa) and quality changes during storage were investigated. The multi-stage immersion treated 3 times in 2 min showed more effective than others to remove microorganisms. Total count of lettuce after immersion in electrolyzed acid water was decreased to 1/100-1/300 of $5.8\;{\times}\;l0^5CFU/g$ of non-immersed lettuce and $2.3\;{\times}\;l0^5CFU/g$ of tap water immersed lettuce. Also coliforms was significantly decreased to 1/3,000 of $3.1\;{\times}\;10^3CFU/g$ after electrolyzed acid water washing. However, microbial levels of electrolyzed acid water treated one became to be similar to those of non-treated lettuce after 3 days of storage at $10^{\circ}C$. The color values of L and b of lettuce treated with electrolyzed acid water were somewhat higher than those of others. Though chlorophyll content of lettuce just after immersion in electrolyzed acid water was 9% lower than those of non-treated one, the content was decreased to the same level of other treatments during storage. Decaying ratio showed the lowest value in lettuce immersed in electrolyzed acid water until 6 days of storage. The sensory tests for overall acceptability and appearance of lettuce immersed in electrolyzed acid water showed higher than those of others until $3{\sim}6$ days of storage.

• Journal of the Society of Disaster Information
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• v.19 no.3
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• pp.698-709
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• 2023

Purpose: In this paper, we would like to analyze the growth rate of existing urban immersion in the downstream during large-scale urban development and the degree of reduction in existing urban immersion in the downstream when small excellent storage facilities are planned in apartment complexes. Method: A large-scale sewage model was built using the SWMM model of the U.S. Environmental Protection Agency, and the impact of flooding in existing downtown areas downstream was analyzed through simulation. The built model included the development zone, the existing downtown area downstream, and the entire river basin that discharges rainwater. Result: As a result of calculating and simulating the minimum excellent reservoir capacity for each apartment block in the study target area, it was found that the immersion of 4,893㎥ based on one hour, 25,815㎥ based on two hours, and 55,528㎥ based on three hours in the downstream urban area. Conclusion: As in this study, large-scale flooding simulation considering the existing downtown area in the downstream shows a significant increase in flooding in the downstream, and if excellent reservoir capacity is planned for each apartment block before development and the construction of excellent reservoirs is recommended.