• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2005.09a
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• pp.201-212
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• 2005

[ $Epoxy/BaTiO_3$ ] composite embedded capacitor films (ECFs) were newly designed fur high dielectric constant and low tolerance (less than ${\pm}15\%$) embedded capacitor fabrication for organic substrates. In terms of material formulation, ECFs are composed of specially formulated epoxy resin and latent curing agent, and in terms of coating process, a comma roll coating method is used for uniform film thickness in large area. Dielectric constant of $BaTiO_3\;&\;SrTiO_3$ composite ECF is measured with MIM capacitor at 100 kHz using LCR meter. Dielectric constant of $BaTiO_3$ ECF is bigger than that of $SrTiO_3$ ECF, and it is due to difference of permittivity of $BaTiO_3\;and\;SrTiO_3$ particles. Dielectric constant of $BaTiO_3\;&\;SrTiO_3$ ECF in high frequency range $(0.5\~10GHz)$ is measured using cavity resonance method. In order to estimate dielectric constant, the reflection coefficient is measured with a network analyzer. Dielectric constant is calculated by observing the frequencies of the resonant cavity modes. About both powders, calculated dielectric constants in this frequency range are about 3/4 of the dielectric constants at 1 MHz. This difference is due to the decrease of the dielectric constant of epoxy matrix. For $BaTiO_3$ ECF, there is the dielectric relaxation at $5\~9GHz$. It is due to changing of polarization mode of $BaTiO_3$ powder. In the case of $SrTiO_3$ ECF, there is no relaxation up to 10GHz. Alternative material for embedded capacitor fabrication is $epoxy/BaTiO_3$ composite embedded capacitor paste (ECP). It uses similar materials formulation like ECF and a screen printing method for film coating. The screen printing method has the advantage of forming capacitor partially in desired part. But the screen printing makes surface irregularity during mask peel-off, Surface flatness is significantly improved by adding some additives and by applying pressure during curing. As a result, dielectric layer with improved thickness uniformity is successfully demonstrated. Using $epoxy/BaTiO_3$ composite ECP, dielectric constant of 63 and specific capacitance of 5.1nF/cm2 were achieved.

• Journal of dental hygiene science
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• v.15 no.4
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• pp.407-412
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• 2015

This study investigated flexural properties of indirect Gum-shade composite resins for esthetic improvement. The material utilized in this study was Crea.lign, Twiny flow and Twiny paste (TP). Ten specimens were fabricated with a dimension of $25{\times}2{\times}2mm$ according to the ISO 4049. After fabrications, specimens were stored in the distilled water for 24 hours at the temperature of $37^{\circ}C$. Three-point bending test was performed in universal testing machine (Instron 3344; Instron, USA) at a crosshead speed of 1 mm/min until the failure occurred. TP exhibited a higher flexural strength (FS) and flexural modulus (FM) compared to the flowable materials. There were significant differences among the three materials in FS and FM. However, there was no significant difference in work of fracture (WOF) in all tested materials (p>0.05). In Weibull analysis, TP showed the greatest Weibull modulus which means a higher reliability of the materials. Also, Gum-shade composite resins revealed a strong correlation in all flexural properties. There was a positive correlation in FS-FM ($r^2=0.99$) and a negative correlation between FS-WOF and FM-WOF ($r^2>0.97$). Therefore, this confirmed that flexural property was important for mechanical behavior evaluation and useful information. To addition, this improved among mechanical properties correlation of materials as important factor.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.7
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• pp.4357-4363
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• 2015

This study is to compare the differences of bonding strength based on the Degassing temperatures and various opaque materials for Ni-Cr alloy specimen which does not contain beryllium(Be). Numerous comparison tests have been performed to measure the bonding strength by experimenting 3-point flexural rigidity tests in order to find out ways of stabilization and enhancement of bonding strength between metal and porcelain. AVOVA, surface component observation experiment by SAM/EDS, and Tukey's HSAD posteriori tests results are as follows: First, The bonding strength in all groups has exceeded the minimum (25MPa) of ISO9693 bonding strength regulation for dental mental-porcelain specimen. Second, The bonding strength of Group V1 was $32.37{\pm}1.91MPa$, $38.25{\pm}1.38MPa$ in Group V2, $46.43{\pm}2.14MPa$ in Group V3 and $47.21{\pm}1.72MPa$ Group V4. The difference has been statistically meaningful. Tukey's HSAD posteriori tests results have shown that the bonding strength in Group V4 was higher than that of Group V1. Third, the bonding strength between metal and porcelain without degassing process was higher than that of with degassing process, and the bonding strength of powder opaque was higher than that of paste opaque. Fourth, Group V4 has ranked the highest on the comparison table of metal and porcelain bonding strength.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.1
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• pp.16-24
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• 2018

In this study, an experiment was conducted to analyze mortar based rheology for 3D printing method application. The tendency of rheological properties due to the change of W/B, binder type, replacement ratio, and super plasticizer which have a great influence on the flow characteristics of concrete was experimentally analyzed. Experiments were carried out by dividing into paste and mortar. In the paste experiment, rheology was analyzed by setting W/B, binder type, replacement ratio, and super plasticizer dosage as main variables. In the mortar experiment, the rheological properties of W/B and sand ratio were analyzed. As a result, as the W/B was increased, the viscosity decreased and the FA ratio to replace FA increased and the viscosity increased. In order to increase the fluidity, substitution of only 5% of SF reduces the shear stress and the viscosity is reduced by about 83%. Mortar rheological evaluation shows that there is a critical section where a large change occurs in the W/B 30 to 40% section. Also, in the same W/B, it is analyzed that there is a critical section where the shear stress increases more than twice in the sand ratio of 50~60%.

• Journal of the Korea Concrete Institute
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• v.20 no.5
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• pp.557-563
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• 2008

Recently, the amount of disposed construction materials like demolished concrete is growing fast and the shortage of natural concrete aggregate is becoming serious. Therefore, recycling of aggregate extracted from the demolished concrete is getting important and use of the recycled aggregate for concrete has been seriously considered. However, the use of the recycled aggregate even for low performance concrete is very limited because recycled aggregate which contains large amount of old mortar has very low quality. Therefore, removing the paste sticked to the recycled aggregate is very important in the manufacturing of high quality recycled aggregate. We have studied a series of research according to complex crushing method, which is removed the ingredient of cement paste from recycled fine aggregate using both the low speed wet abrasion crusher as mechanical process and the acid treatment as chemical processes. This paper is to analyze the quality of the recycled fine aggregate produced by those complex method and investigate optimum manufacturing condition for recycled fine aggregate by the design of experiments. The experimental parameters considered are water ratio, coase aggregate ratio, and abrasion time. As a result, data concerning the properties of recycled sand were obtained. It was found that high quality recycled fine aggregate could be to obtain at the condition of the fifteen minute of abrasion-crusher time and the over 1.0 of recycled coarse aggregate ratio.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.2
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• pp.195-200
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• 2009

This study was performed to investigate the quality characteristics and antioxidant activity of garlic yanggaeng added with several calcium sources (calcium carbonate, calcium citrate, calcium lactate, mixed calcium and calcium powder). The pH and lightness of calcium-added garlic yanggaeng decreased compared with control. Lightness of garlic yanggaeng added with calcium lactate, calcium carbonate and calcium powder was similar with that of control. As for texture profile analysis, hardness of garlic yanggaeng added with calcium lactate, calcium carbonate and calcium powder was increased compared to control. The antioxidant activities determined by DPPH and hydroxyl radical scavenging activities of the garlic yanggaeng added with calcium lactate, calcium carbonate and calcium powder were significantly higher than those of control. The pungent and taste of garlic were reduced in garlic yanggaeng added with calcium lactate, calcium carbonate and calcium powder. Consumer test showed that the score of overall acceptance was higher in the garlic yanggaeng added with calcium lactate and calcium carbonate, compared to those of other calcium sources. Based on these results, it was suggested that garlic paste added with calcium carbonate or calcium lactate may be useful materials to improve quality of garlic yanggaeng.

• Journal of Korean society of Dental Hygiene
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• v.6 no.1
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• pp.49-61
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• 2006

This study was intended to identify the pregnant women's oral health care behaviors and the necessity of active oral care so as to use in the dental hygiene education at dental clinics as basic materials to inform the importance of oral health during pregnancy and instruct how to improve it. And to suggest a dental service direction for dental hygienists, 150 pregnant women who visited the Ostetrics and Genecology Clinics located in tl,e north part of Cholla province were surveyed with questionnaire on their oral care behaviors, from september to October in 2004. The findings were as below: 1. 43.8% of the pregnant women have ever used the dental care institutes within the recent 3 months during pregnancy period. The purpose of the visits was mostly treatment of dental caries, accounting for 40.0%. Next came the treatment of periodontal diseases, accounting for 33.8%. 2. At dental care service, 84.7% of the pregnant women informed the clinic staff of their pregnancy, 12.0% of the pregnant women were having periodical oral examination. 3. 56.7% of the pregnant women have ever inquired about oral care methods, 24.0% of the pregnant women have ever taken any oral health education, of whom 47.1% had higher schooling over graduate school, with a statistically signifiant difference. 4. 55.3% of the pregnant women made changes in their oral care practice after they got pregnant. Change of oral care practices was more obvious in those who had higher schooling background, of whom specialist women accounted 76.9%. Change of oral care practices after pregnancy was statistically significantly different to the academic background and occupation. 5. Of the changes in oral care practice after pregnancy, 51.8% of the pregnant women answered they got sensitive to change in their oral status, and 39.8% increased the frequency of tooth brushing. 6. In selecting a tooth paste after they got pregnant, 58.0% of the women didn't give any special consideration to the kind of tooth paste, while 10.7% women as low selected such tooth pastes that contain fluoride. 7. Pregnant women's route for gathering oral care information was mostly mass media and Internet which accounted for 50.7%.

• Applied Chemistry for Engineering
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• v.9 no.7
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• pp.1011-1017
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• 1998

$YBa_2Cu_3O_{6+x}(Y123)-Ag$ high-Tc superconducting wires were fabricated by plastic extrusion technique using pyrophoric synthetic and mechanical mixing powder with and without Ag addition(20 wt.%). This method involves powder preparation, plastic paste making, die extrusion, binder burn-out and the sintering process. In order to fabricate a good-quality superconducting body, it is required to use homogeneous and fine-size power as a starting materials. $Y_2O_3-BaCO_3-CuO$ precursor powders with/without Ag addition were prepared both by pyrophoric synthetic(PS) and mechanical mixing(MM) method of raw powders. The formation kinetics of the powder mixtures into Y123 phase was investigated at various temperatures and times in air atmosphere. The powder prepared by PS method was more easily converted into a Y123 phase than the MM powder. The fine size and good chemical homogeneity of the powder prepared by PS method is attributable to the fast formation into a Y123 phase. The critical current density($J_c$) of the Y123-Ag superconducting wires made by plastic extrusion method were in the range of $150A/cm^2{\sim}230A/cm^2$. depending on the charateristics of starting material powders. $J_c$ of the wire prepared by pyrophoric synthetic powder with 20 wt.% Ag addition was $230A/cm^2$.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2005.09a
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• pp.1-23
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• 2005

Kochujang, a fermented hot pepper soybean paste, is a spicy condiment mixed with red pepper, boiled rice and mold fermented soybean (as koji) which is then fermented for several months. It has unique taste of hot, sweet, salty and savory flavor by all mixed ingredients by fermentation, and is one of most famous Korean traditional foods. The scale of the kochujang industry is about 200 billion won in Korea, and 7.8 million dollars and 4,500 tons in exports. Although it is still not a large part of the food industry in Korea, the scale of soy products will increase because it is a major subsidiary food in our dietary life and has grown from a homemade to a mass produced product. Kochujang has the largest market in the scale of sales among fermented soybean products and has merit because of its domestic base and its ability to grow to an international market due to its unique fermented taste. In order to make kochujang an international food, it Is necessary to study the scientific development of kochujang and the diversity of products using kochujang that are fitted to the taste of people around the world. In addition, participation in various exhibitions and food fairs supported by the government should help to promote kochujang throughout the world. In addition, these should be actively supported by the related businesses. Red pepper, a major ingredient in kochujang, has been widely studied and shown to have a positive effect on the reduction of fat, on the strengthening of the immune system, and on active biological functions. A fermented spice like kochujang has been shown to be beneficial for the body due to the process of fermentation rather than from the red pepper itself. If we prove the various biological functions of kochujang with a particular taste and flavor, it will energize a new market. It is necessary for business to make a continuous effort supported fly the scientific world and by government policy, in order to introduce this traditional food to the world. In the present day, the kochujang market is now on a firm basis and has been activated in the field of its study. Now, it is possible to achieve the birth of a secondary international market by concentrating on these efforts.

• Journal of the Korea Concrete Institute
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• v.28 no.3
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• pp.341-348
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• 2016

At present, about 40 million tons of concrete is dismantled each year, which accounts for the largest portion of the total amount of construction waste with 60.8%. It is known about 97.5% of it is recycled. However, most of the usage of waste concrete is limited to lower value-added business areas, and considering the increasing amount of waste concrete generated due to the deterioration of structures, the need for converting waste concrete to structural concrete is urgent. Therefore, this study aims at estimating the period for the optimum carbonation reforming to improve the quality of recycled aggregate, by making use of the method of accelerated carbonation reforming of the bonding heterogeneous (cement paste and mortar) for the purpose of converting recycled aggregate to structural concrete. Based on the period appropriate for the heterogeneous thickness and each bonding thickness of recycled aggregate which was drawn from previous studies, the changes in the characteristics and physical properties of pore structure according to progress of accelerated carbonation were analyzed. The result shows that with the progress of carbonation, the pore volume and the percentage of water absorption of the bonding heterogeneous decreased and the density increased, which indicates improvement of the product quality. But after certain age, the tendency was reversed and the product quality deteriorated. Synthesizing the results of previous studies and those of the present study, this study proposed 4 days and 14 days respectively for the period for the optimum carbonation reforming of recycled fine aggregate and recycled coarse aggregate.