• Journal of Industrial Technology
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• v.35
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• pp.35-39
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• 2015

One of the purposes of the study was to investigate and compare the physical properties(depth of light cure, degree of conversion, water absorption) of 4 kinds of composit resins prepared in this lab; Bis-GMA based, Bis-EMA based, Bis-GMA/UDMA based, and Bis-EMA/UDMA based composit. Another aim was to compare the physical properties of the composit resins with those of the commercialized products(Charmfil flow(Denkist), Quadrant flow(CAVEX)) in market. All of the composit resins and the commercialized products showed almost same values of the physical properties. It was found that all of the composit resins prepared in this lab satisfied the physical properties specified in ISO 4049.

• Journal of the Korean Ceramic Society
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• v.54 no.6
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• pp.470-477
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• 2017

Ceramic processing to fabricate 3D complex ceramic structures is crucial for structural, energy, environmental, and biomedical applications. A unique process is ceramic stereolithography, which builds ceramic green objects from CAD files from many thin liquid layers of powder in monomer, which are solidified by polymerization with a UV laser, thereby "writing" the design for each slice. This approach directly writes layers in liquid ceramic suspension and allows one to fabricate ceramic parts and products having more accurate, complex geometries and smooth surfaces. In this paper, both UV curable materials and processes are presented. We focus on the basic material principles associated with free radical polymerization and rheological behavior, cure depth and broadening of cured lines, scattering at ceramic interface and their corresponding simulation. The immediate potentials for ceramic AM to change industry fabrication are also highlighted.

• Korean Parent-Child Health Journal
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• v.9 no.1
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• pp.17-32
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• 2006

The purpose of this study was to understand mother's experience of caring child with a severe atopic dermatitis. Twelve participants were selected and collected on their caring difficulties using in-depth interview. Data were analyzed according to the method of Colaizzi. Significant statements were extracted from the data. From the significant statement, 18 clusters of themes and 7 categories were emerged. Eighteen cluster of themes formed 7 categories : Thinking of atopic dermatitis during 24 hour, Mom would cure you, You are atopic, I'm depressive, I need 12 or more bodies to take care of him/her, Great conversion of daily life, From a bitterness to a frailness, In peace with an atopic dermatitis. In this study, it was implicated that mothers were suffered from caring children with an atopic dermatitis and nurses need to have more interests in the maternal stress and their quality of life as well as provision of information.

• Applied Chemistry
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• v.9 no.2
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• pp.25-28
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• 2005

To evaluate the dental restorative application of polymer composites filled with hydroxyapatite (HAP) which is an inorganic component of human bone material, dental properties of the polymer composites were investigated. A visible light system was utilized to activate the acrylate resin matrix of the composites. Maximum loading percentage of HAP in composite was 65 wt% and the depth of cure was 6.0 mm which can be applicable for dental restoration. With increasing the HAP content, degree of conversion of polymer composites was slightly decreased, however, polymerization shrinkage value was not varied. Diametral tensile strength value was enhanced with an increase of HAP content, however, there was no strict trend between flexural strength and HAP concentration. Anyhow, polymer composites prepared herein have superior mechanical properties sufficient specifications applicable to dental materials.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.2
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• pp.280-289
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• 2004

Adequate polymerization is a crucial factor in obtaining optimal physical properties and clinical performance of resin composite restorative materials. The purpose of this study was to determine the effectiveness of shade and depth on dental composite resin polymerized with plasma arc curing unit employing FTIR and microhardness. From this experiment, the following results were obtained : 1. The light transmission and microhardness by mode 6 in plasma arc curing were similar to by 20 secs in halogen light curing. 2. The experimental groups of A1, A2, A3, A3.5 were not signifcant difference to light transmission and microhardness on surface and 2mm depth, but were significant difference on 3mm and 4mm depth. Especially light transmission and microhardness were small in darker shade and deeper thickness. 3. Compared with depth cure, uncured monomer amount increased at more than 2mm depth. 4. The light transmission by FTIR and polymerization by microhardness were significant corelation.

• Journal of Oriental Neuropsychiatry
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• v.23 no.1
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• pp.1-15
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• 2012

Objectives : The objective of this study is the Basic research for mind and body cure protocol construction through the Sim(心) study at Buddhism Medicine, Constitutional Medicine, and Oriental Medicine. Methods : 1. The Sim(心) in Buddhism is a target of spiritual culture and subjective awareness of An ascetic person in interior psychology. In this research, the Sim(心) has been modified within a concept of Early Buddhism and You-sic in order to have medical logicality. 2. Since the study deep into Sim(心) within Confucianism has various aspects, each Confucian's theory argument or era. We limited the significance of the Sim(心) to be associated with the category of the Sim(心) in Sasang Constitutional Medicine which is a product of practical Confucianism. 3. The criteria of debate for the Sim(心) is based on the "Hwang-je-nae-gyoung", because "Hwang-je-nae-gyoung" is founded to definite the term regarding spirit or mind in Oriental medicine Results : 1. "Hwang-je-nae-gyoung" which came from thought of You-Sic, thought of Taoism, and Early Buddhism becomes the theoretical basis for the Sim(心) in Buddhism Medicine, Sasang Constitutional Medicine, and Oriental Medicine. 2. The Sim(心) in the mind psychology of Buddhism Medicine, Sasang Constitutional Medicine, and Oriental Medicine has active aspects. but the visual thing // There are visual aspects being contrasted with 'Sim(心)' of mind psychology and aspects of activity in Buddhism medicine, Sasang constitutional Medicine and Oriental Medicine; which are 'Hrd', 'Hrdaya', 'four-large' 'five base', 'chin, chest, navel and abdomen', 'head, shoulder, waist and buttocks' consisting 'the body', and the heart and 'four interorgans' from the study of symbolical interorgans). In Buddhism Medicine, Sim(心)'s Epistemology is the most extensively understood fact about 'Sim(心)', and for Sasang Constitutional Medicine and Oriental Medicine. 'Sim(心)' is limited as an 'Element' that comprises the body. 3. The Functional area of the Sim(心) in the Buddhism Medicine, Sasang Constitutional Medicine, Oriental Medicine is composed with 'consciousness(意識)' 'manas-vij_na(末那識)', '_aya-vij_na(阿賴耶識)', 'mind greed(心欲)', 'Li(理)' and 'Sin(神)', about the interpretive area of 'Sim(心)', 'Sin(神)' of Oriental medicine is the most comprehensive concept, and on the side of the depth of 'thinking' and 'consciousness', '_aya-vij_na(阿賴耶識)' from Buddhism Medicine in the key point. 4. The Sim(心) in the Buddhism Medicine, Sasang Constitutional Medicine, has the positive and negative aspects, such as the 'Dukkha(煩惱)' and A merciful heart or Human Sim(心) and Taoism Sim(心).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.503-509
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• 2019

The demand for smaller, faster, and multi-functional mobile devices in increasing at a rapidly increasing rate. In response to these trends, Stacked Chip Scale Package (SCSP) is used widely in the assembly industry. A film type adhesive called die attach film (DAF) is used widely for bonding chips in SCSP. The DAF requires high flowability at high die attachment temperatures for bonding chips on organic substrates, where the DAF needs to feel the gap depth, or for bonding the same sized dies, where the DAF needs to penetrate bonding wires. In this study, the mixture design of experiment (DOE) was performed for three raw materials to obtain the optimized DAF recipe for low elastic modulus at high temperature. Three components are acrylic polymer (SG-P3) and two solid epoxy resins (YD011 and YDCN500-1P) with different softening points. According to the DOE results, the elastic modulus at high temperature was influenced greatly by SG-P3. The elastic modulus at $100^{\circ}C$ decreased from 1.0 MPa to 0.2 MPa as the amount of SG-P3 was decreased by 20%. In contrast, the elastic modulus at room temperature was dominated by YD011, an epoxy with a higher softening point. The optimized DAF recipe showed approximately 98.4% pickup performance when a UV dicing tape was used. A DAF crack that occurred in curing was effectively suppressed through optimization of the cure accelerator amount and two-step cure schedule. The imizadole type accelerator showed better performance than the amine type accelerator.

• The korean journal of orthodontics
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• v.23 no.1 s.40
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• pp.75-88
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• 1993

Recent reports indicate that shorter etching times than 60 seconds can be adopted without affecting the bond strength and clinical disadvantages. The purpose of this in vitro study was to compare the shear bone strength and to measure depth of etch at different etching time length. One hundred and eight extracted bovine lower central incisors were embedded each in a tooth cup with cold-cure acrylic resin. The facial surfaces of the teeth were ground wet with 600-, 800-, 1000-, and 1200-grit Sic papers, and finally polished with a water slurry of extrafine silicon carbide powder, washed with tap water, and dried with hot air. Nine groups of nine prepared teeth were etched with a commercial($38\%$ phosphoric acid solution) for 0, 5, 10, 15, 20, 30, 60, 90, and 120 seconds, respectively, rinsed with tap water, and dried with hot air. One conditioned teeth from every group was selected randomly for the scanning electron microscopic examination, and the remaining eight teeth of the groups were used for measuring the push shear bond strength after bonding brackets and immensing them in the $36.5^{\circ}C$ water for 24 hours. Another nine groups of three teeth were used for measuring the depth of etch and surface roughness with a surface profilometer. after pieces of adhesive tape of 3mm inner diameter positioned on the ground enamel surfaces, and etched with the above mentioned. The data obtained form the above expeiments were analysed statistically with one way ANOVA and Dunkan's multiple range test with the $95\%$ confidence level. The results and conclusion of the study were as follows; 1. The results of shear bond strength for the given experimental etching times were not statistically different, but showed the tendency of decreasing shear bone strength after over 60 seconds etching times. 2. On the scanning election microscopic examination, it was observed that the morphological patterns of etched enamel surface for 5 to 20 seconds were similar and consitent, and those for 30 to 120 seconds showed increasing over-etched patterns depending on the length of etching times. 3. The depth of etch was increased almost proportionally by the length of etching times, but it was not associated with the shear bond strength. 4. The surface roughness increased depending on the length of etching times, but it was not associated with the shear bond strength. 5. This experiment indicated that proper etching time with $38\%$ phosphoric acid solution is in the range of 5 to 30 seconds.

• Korean Journal of Adult Nursing
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• v.18 no.1
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• pp.115-124
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• 2006

Purpose: The purpose of this study was to propose a theoretical model of hope commonly held by the cancer patients just after surgery, under the assumptions that hope of those patients is not only realistic and disease oriented but in dialectical circulation. Method: A theoretical model was generated through 4 steps: exploring a hope structure by synthesizing the relevant hope structures expressed in Kim and Tae's studies, in-depth literature review, examining the meanings of the concepts consisted of the structure in use and their causal relations in logical adequacy, proposing a theoretical structure through synthesizing the causal relations, and diagramming the structure. Results: The proposed theoretical model involves concepts such as Cancer Related Uncertainty (CRU), Efforts to Find out the Possibility of Cure or Recovery (EFPCR), and Hopefulness or Hopelessness. The 'EFPCR' is stipulated as 'Behaviors Related to Looking for Evidences or Cues (BRLEC)' and 'Formation of Cognitive Schema (FCS)'. In the model, Hopefulness is directly influenced by 'CRU in low', which is affected by 'FCS in good' from the result of EFPCR started with 'CRU in increase' while 'CRU with increase' from the result from EFPCR has direct effect on Hopelessness. Conclusion: The theoretical model would be used to enhancing hope of the cancer patients in post-operation.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.6 s.183
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• pp.174-179
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• 2006

The curing characteristics of a photocurable resin are critical factors that often decide the ultimate resolution and structural sharpness of a final product fabricated by microstereolithography$(\mu-STL)$. In this study, we investigated the curing characteristics of the FA1260T photopolymer under a visible laser light of 42nm wavelength. Modification of the curing property of the FA1260T is attempted to reduce the cure depth $(D_c)$ by adding a radical quencher to the resin. Also, an organic solvent was used to reduce the resin viscosity for an improvement of the flatness of the liquid surface during layer-by-layer curing. As a result, the minimum $D_c$ has been reduced over a factor of 3 with no abrupt increase. Samples of three dimensional microstructures fabricated using the modified FA1260T are presented.