• Title/Summary/Keyword: school bonding

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Evaluation for Ultimate Flexural Strength of Steel Composite Girder with High Strength Concrete (고강도 콘크리트 강합성 거더의 극한휨강도 실험 평가)

  • Kim, Woon Hak;Lee, Juwon;Lee, Seokmin
    • Journal of the Society of Disaster Information
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    • v.16 no.4
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    • pp.796-805
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    • 2020
  • Purpose: A static loading test was performed to evaluate the ultimate flexural strength of a girder in which 80MPa high-strength concrete was synthesized on the compressive flange of the I-shape steel girder. Method: This test is designed and fabricated two types of specimens with different shear-connection specifications, and evaluated their ultimate flexural behavior until reaching the extreme event limit states. In addition, the ultimate strength was evaluated by comparing the test results and the results of the strain compatibility method. Result: By confirming the displacement within 0.02mm as a result of the relative slip measurement, it was verified that the two specimens secured perfect bonding. Therefore, the difference in the shear specification does not have a great effect on the stiffness, and if the specimens are completely synthesized, there is no difference in the behavior until it reaches the extreme-event limit states. Conclusion: The girder to be tested has a working load within the elastic range and meets the usability requirements for allowable deflection. Therefore, even if a part of the casing is subjected to the tensile force at the level of cracking, the deck will first reach the compression failure due to the role of the reinforcing bar.

A Study on Grotesque Images in Dimitris Papaioannou's Work (디미트리스 파파이오아누 작품에 나타난 그로테스크 이미지 연구)

  • CHOI, Young-hyun
    • Trans-
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    • v.11
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    • pp.65-95
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    • 2021
  • Grotesque, which has often emerged as a breakthrough in Western art to protest rational and classical pure beauty, is often seen in modern art. Grotesque, along with the concept of pendulum, appears in infinitely expanded forms across cultures, arts, and society. In particular, transformed body images through deformatization and deformatization of the body are interpreted as strong rejections that seek to break away from formalized beauty. The main purpose of this study is how the body reproduced through body deformation, distortion, and bonding in Dimitris Papaioannou's work can be interpreted within the grotesque category. To this end, he examines the Grotesque discourse and modern meaning underlying the interpretation of the work and identifies how the fragmented and expanding body, which is currently actively discussed in the dance world, has an interaction with Grotesque. It selects , , , and , which are the main attributes of the grotesque, focus on conflicting familiarity, life, hatred, and beauty. Based on this, we would like to confirm that in contemporary dance, the reconstructed body reveals concealed things rather than expressing an unrealistic fictional world, and seeks new possibilities beyond boundaries as well as reconsider existing aesthetic views.

Development of Gel Sheet Mask Based on Physical Properties Study of Tamarindus indica Seed Gum, Ethanol, Polyols, and Acid/Base Reaction (타마린드씨검과 에탄올, 폴리올 및 산·염기 반응의 물성 연구를 바탕으로 한 겔 시트 마스크의 개발)

  • Yeo, Hye Lim;Lee, Hyo Jin;Kang, Hae-Ran;Jung, So Young;Lee, So Min;Kim, Hyung Mook;Kwak, Byeong-Mun;Lee, Mi-Gi;Bin, Bum-Ho
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.47 no.4
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    • pp.305-316
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    • 2021
  • This study relates to the development of a new gel sheet mask that finally does not require support based on the reactivity and acid/base reaction experiments of Tamarindus indica seed gum (TG), ethanol, and polyols. When TG and a specific alcohol was mixed at a certain mixing ratio, a transparent gel is formed by reaction with each component, and thus a gel sheet mask without support might be obtained using the mixture. In order to maximize skin tone improvement, a carbonation system of acid and base reactions was introduced, and skin brightness and moisturizing power were evaluated using a spectrophotometer and a moisture measuring device. Through this study, it is expected that the gelation reaction by hydrogen bonding of TG, ethanol, and polyols can be developed into various types, and the gel sheet mask formulation introduced in this study is expected to help develop new products in the future.

The Parent-adolescent Career Congruence Process as a Mediator between Independent vs Interdependent Parent-adolescent Relationships and Career Identity (상호협조적-독립적 부모자녀관계와 진로정체감과의 관계에서 부모자녀진로합치과정의 매개효과)

  • Sohn, Youngmi;Park, Cheongyeul
    • Korean Journal of Culture and Social Issue
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    • v.27 no.3
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    • pp.325-350
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    • 2021
  • The purpose of this study was to examine the mediating effect of the parent-adolescent career congruence process in the association between the parent-adolescent relationship and career identity of South Korean college students. In particular, we investigated which kind of career congruence process mediates the positive effect of the interdependent parent-adolescent relationship (in support of emotional bond and filial piety) and the independent parent-adolescent relationship (in support of independence and autonomy) on career identity. Data of 509 college students were analyzed for this study, and parallel multiple mediation analysis was performed. As a result, the complementary and attunement congruence process fully mediated the relationship between parent-adolescent affective bonding and career identity. Authoritative filial piety had a negative direct effect on career identity, but a positive indirect effect by mediating the complementary and attunement congruence process. The mediation analysis showed that both complementary and attunement congruence process fully mediated the association between independent parent-adolescent relationship and career identity. However, family intrusion had only a negative direct effect on career identity. On the other hand, the supplementary congruence process did not have significant mediating effects between all types of parent-adolescent relationships and career identity. Also, the supplementary congruence process had a negative direct effect on career identity. Based on these results, we discussed culturally universal and culturally specific characteristics of the relationship between parent-adolescent relationships and career identity, along with the limitations and recommendations for future research.

Design Optimization to achieve an enhanced flatness of a Lab-on-a-Disc for liquid biopsy (액체생검용 Lab-on-a-Disc의 평탄도 향상을 위한 최적화)

  • Seokkwan Hong;Jeong-Won Lee;Taek Yong Hwang;Sung-Hun Lee;Kyung-Tae Kim;Tae Gon Kang;Chul Jin Hwang
    • Design & Manufacturing
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    • v.17 no.1
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    • pp.20-26
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    • 2023
  • Lab-on-a-disc is a circular disc shape of cartridge that can be used for blood-based liquid biopsy to diagnose an early stage of cancer. Currently, liquid biopsies are regarded as a time-consuming process, and require sophisticated skills to precisely separate cell-free DNA (cfDNA) and circulating tumor cells (CTCs) floating in the bloodstream for accurate diagnosis. However, by applying the lab-on-a-disc to liquid biopsy, the entire process can be operated automatically. To do so, the lab-on-a-disc should be designed to prevent blood leakage during the centrifugation, transport, and dilution of blood inside the lab-on-a-disc in the process of liquid biopsy. In this study, the main components of lab-on-a-disc for liquid biopsy are fabricated by injection molding for mass production, and ultrasonic welding is employed to ensure the bonding strength between the components. To guarantee accurate ultrasonic welding, the flatness of the components is optimized numerically by using the response surface methodology with four main injection molding processing parameters, including the mold & resin temperatures, the injection speed, and the packing pressure. The 27 times finite element analyses using Moldflow® reveal that the injection time and the packing pressure are the critical factors affecting the flatness of the components with an optimal set of values for all four processing parameters. To further improve the flatness of the lab-on-a-disc components for stable mass production, a quarter-disc shape of lab-on-a-disc with a radius of 75 mm is used instead of a full circular shape of the disc, and this significantly decreases the standard deviation of flatness to 30% due to the reduced overall length of the injection molded components by one-half. Moreover, it is also beneficial to use a quarter disc shape to manage the deviation of flatness under 3 sigma limits.

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Types of Solidarity between Parents and Children and Life Satisfaction of Old Adults: Focusing on comparison between urban and rural area (노년기 부모자녀 결속 유형과 삶의 만족에 관한 연구: 도시 농촌 간 지역 비교를 중심으로)

  • Kim, Myoung-il;Kim, Soon Eun
    • 한국노년학
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    • v.39 no.1
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    • pp.145-167
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    • 2019
  • The purpose of this study is to examine the solidarity types between parents-children and to verify whether the types of solidarity relationships are directly related to life satisfaction of older adults. To achieve this, 2,072 Korean elderlies from proportional stratified sample were participated, and the data was divided into urban and rural area where respondents live in. The Latent Profile Analysis(LPA), multiple regression analysis were mainly used for data analysis. The results of the study were as follows: The major findings are following. Patterns of parental bond among urban and rural elderly were classified into three(urban) and two(rural) patterns. For the effect of each parental bonding pattern on life satisfaction, positive effect of parental bond was found only in urban dwellers. In other words, for older people in rural areas, parental bond did not significantly affected on life satisfaction. However, elderly in rural area showed non-familial factor based relationship, such as social capital(community trust, social cohesion, and social support), was influenced their life satisfaction rather than relationship with children. Finding from the study highlight political and practical implications for improving life satisfaction for the elderly.

Effect of Acid Treatment on Pd/C Catalysts for Improving Selective Hydrogenation of Phenol (페놀의 선택적 수소화 반응성 향상을 위한 Pd/C 촉매의 산 처리 효과)

  • Hayoon Park;Ye Eun Kim;Jungho Jae;Man Sig Lee
    • Clean Technology
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    • v.30 no.2
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    • pp.145-156
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    • 2024
  • Carbon has a large specific area and excellent chemical stability, so research on its use as a catalyst support is actively conducted. When using carbon as a support, the pretreatment process is essential. Through pretreatment of carbon, the growth of metal nanoparticles can be controlled and the bonding strength between the support and metal particles can be improved. In this study, carbon was pretreated for surface modification and 5 wt% Pd/C catalysts were synthesized using it as a support. Catalytic activity was evaluated through phenol hydrogenation. To compare with nitric acid, which is commonly used in carbon pretreatment, carbon pretreatment was performed using organic acid. Pd/C treated with gluconic acid showed the highest activity, with 94.93% phenol conversion and 92.76% cyclohexanone selectivity. Therefore, it is expected that pretreatment of the carbon support using organic acid will not only overcome the disadvantages of inorganic acid treatment but also improve catalyst performance.

Comparison of shear, tensile and shear/tensile combined bonding strengths in bracket base configurations (브라켓 기저부 형태에 따른 전단, 인장, 전단/인장복합결합강도의 비교)

  • Lee, Choon-Bong;Lee, Seong-Ho;Kim, Jong-Ghee
    • The korean journal of orthodontics
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    • v.29 no.5 s.76
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    • pp.599-611
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    • 1999
  • The purpose of this study was to evaluate shear, tensile and shear/tensile combined bond strengths(SBS, TBS, S/TBS) in various orthodontic brackets bonded to human teeth with chemically cured adhesive (Ortho-one, Bisco, USA). Five types of metal brackets with various bracket base configurations (Micro-Loc base(Tomy, Japan), Chessboard base(Daesung, Korea), Non-Etched Foil Mesh base(Dentarum, Germany), Micro-Etched Foil Mesh base(Ortho Organiners, USA), Integral base(Unitek, USA)) were used in this study. Shear, tensile and shear/tensile combined bond strengths according to the direction of force were measured by universal testing machine. The bracket base surface after bond strength test were examined by stereoscope and scanning electron microscope. The assessment of resin remnant on bracket base surface was carried out by ARI(adhesive remnant index). The results obtained were summarized as follows, 1. In all brackets, SBS was in the greatest value(p<0.05), TBS was in 50% level and S/TBS was in 30% level of SBS. 2. In bond strength, Micro-Loc base bracket showed the maximum bond strength($SBS:22.86{\pm}1.37kgf,\;TBS:11.37{\pm}0.42kgf,\;S/TBS:6.69{\pm}0.34kgf$) and Integral base bracket showed the minimum bond strength($SBS:10.52{\pm}1.27kgf,\;TBS:4.27{\pm}1.08kgf,\;S/TBS:2.94{\pm}0.58kgf) (p<0.05). 3. In bond strength per unit area, Integral base bracket showed the minimum value, Micro-Loc base and Chessboard base brackets were in similar value(p>0.05). Non-Etched Foil Mesh base and Micro-Etched Foil Mesh base bracket were similar in SBS and TBS(p>0.05), but Micro-Etched Foil Mesh base bracket was greater than Non-Etched Foil Mesh base bracket in S/TBS(p<0.05). 4. Bond failure sites were mainly between bracket base and adhesive, therefore ARI scores were low.

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THE MORPHOLOGICAL OBSERVATION OF HUMAN GINGIVAL FIBROBLASTS ATTACHMENT AND SPREADING ON THE MECHANICAL TREATED TITANIUM PLASMA SPRAYED IMPLANT SURFACE (기계적 표면 처리된 TITANIUM PLASMA SPRAYED IMPLANT에 대한 치은섬유아세포전개양상의 형태학적 관찰)

  • Whang, Yun-Hi;Lee, Jae-Mok;Suh, Jo-Young
    • Journal of Periodontal and Implant Science
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    • v.25 no.3
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    • pp.741-755
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    • 1995
  • Currently titanium is the material of choice for implants because of its biological acceptance. This high degree of biocompatibility is thought to result, in part, from the protective and stable oxide layer that presumably aids in the bonding of the extracellular matrix at the implant-tissue interface. Endosseous dental implants are interfaced with bone, connective tissue, and epithelium when implanted into the jaw bone. The soft tissue interface including connective tissue and epithelium is one of the most critical factors in the determination of implant maintenance and prognosis. For maintenance of failing or failed implants, it is essential to treat the implant fixture surface to remove bacterial endotoxins and make a surface tolerated by surrounding soft and hard tissues. In this study, the effect of mechanical treatment on titanium plasma sprayed implant on adhesiveness and proliferation of human gingival fibroblasts and changed surface characteristics were studied. titanium plasma sprayed discs manufactured by Friedrichsfeld company were treated with loaw speed stone bur, a rubber point and a jetpolisher. Its surface components were analyzed with Energy dispersive X-ray spectroscopy to evaluate whether the surface characteristics were altered or not. To observe the spreading pattern of the human gingival fibroblasts which attached to the all specimens author used the scanning electron microscope. The results were as follows : Pure titanium and plasma sprayed titanium, stone polished titanium showed titanium peak and small amout of aluminum, so there was no alteration on surface characteristics. Under the scanning electron microscopic examination in the initial attachment of human gingival fibroblast, there was a slight enhancement in pure titanium, stone polished titanium than plasma sprayed titanium. After 6 hours, the pure titanium and stone polished titanium showed human gingival fibroblasts were elongated and connected with numerous processes. Human gingival fibroblasts were more intimately attached on the pure titanium discs than on the other discs. The human gingival fibroblasts attached on the plasma sprayed titanium by thin and elongated processes. After 24 hours, the human gingival fibroblasts connected with each other via numerous processes and compeletly covered the pure titanium and stone polshed titanium discs. Human gingival fibroblasts had multiple point contacts with more long and thin lamellopodia and showed a little bare surface on plasma sprayed titanium discs.

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THE STUDY ON THE MICROLEAKAGE PATTERN OF FLOWABLE COMPOSITE RESIN RESTORATIONS ACCORDING TO THE TYPE OF ADHESIVE MATERIALS (접착제에 따른 유동성 복합 레진 수복물의 미세누출 양상에 관한 연구)

  • Park, Ji-Eun;Kim, Jong-Soo;Yoo, Seung-Hoon
    • Journal of the korean academy of Pediatric Dentistry
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    • v.35 no.3
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    • pp.456-468
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    • 2008
  • This study was performed to evaluate the quality of newly offered dentin bonding system($AdheSE^{(R)}$ One) by comparing the degree of microleakage measured with those of several conventional adhesive materials(AQ Bond Plus and $Adper^{TM}$ Single Bond 2). The quality of hybrid layer and resin tags was analyzed by observing restoration/ tooth interface under SEM. All-in-one system is in the limelight for having advantage of reducing chair time of children with difficult behavior pattern. Therefore the possibility of clinical application of All-in-one system was evaluated. The results obtained are as follows; 1. At the enamel margin, group II(AQ Bond Plus) showed the highest value of microleakage, and the other groups showed decreased value in order of group III($AdheSE^{(R)}$ One) and I($Adper^{TM}$ Single Bond 2). There was statistically significant difference between group II and the others(p<0.05), and no statistical difference was found between group I and III. 2. At the dentin margin, microleakage value was increased in order of group II, I, III and significant difference between all groups(p<0.05). 3. In group I and III, microleakage value measured at the enamel margin was significantly lower than that seen at the dentin margin(p<0.05), and there was no statistical difference in group II. 4. Resin tags observed under SEM were very weak and tangled in group II and III while the strong and thick tags were observed in group I. In conclusion, careful case selection and accurate clinical application is recommended in using AQ Bond Plus and $AdheSE^{(R)}$ One, giving consideration of the results showing its higher microleakage and weaker strength than $Adper^{TM}$ Single Bond 2.

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