• Carbon letters
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• v.10 no.2
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• pp.94-96
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• 2009

[ $C_f/C-Cu$ ]composites were fabricated by infiltrating molten Cu into different $C_f/C$ preforms prepared by chemical vapor infiltration, resin impregnation and carbonization. The microstructure and properties of the composites were investigated. The results show that Cu in the composites filled the pores and showed network-like distribution. Compared with homemade J204 brush material and certain grade pantograph slider from abroad, the composites have higher flexural strength and better electrical conductivity. The friction and wear properties of the composites are better than that of J204, and closed to that of the abroad material.

• The korean journal of orthodontics
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• v.38 no.3
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• pp.214-222
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• 2008

Objective: The aim of this study was to investigate the experimental brush wear pattern of a light cured surface sealant, Biscover (Bisco, Schaumburg, IL), and to evaluate its cariostatic effect. Methods: Caries-free human premolars were used for the Biscover coating group (n = 90) and the control group (n = 10). The Biscover coating group was randomly assigned to nine subgroups of 10 each and the control group was assigned to two subgroups of 5 each according to the number of brushing strokes. An experimental 3-body wear test was conducted under different strokes of wear test. Tooth-brushing was accomplished with movement of each brush head set at a frequency of 100 rpm under a force of 1.5N, Surface roughness was tested before, and after Biscover coating, and after brushing. Then, each of the 10 teeth of both groups were placed in artificial caries inducing solution for 7 days. All tooth surfaces were assessed using scanning electron microscopy. Results: Biscover coated surfaces showed a smoother texture than enamel surfaces. The roughness was increased after experimental brushing and after 10,800 brushing strokes, the whole layer of Biscover wore out. However, teeth in the Biscover coating group had a cariostatic effect in cariogenic conditions. Conclusions: We suggest that white lesions in orthodontic patients can be suppressed by topical applications of Biscover.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.12
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• pp.1253-1258
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• 2013

Ceramic particles as polishing abrasives are often used in a magnetic abrasive polishing process because they have strong wear resistance. Non-ferromagnetic ceramic abrasives should be mixed with ferromagnetic iron particles for controlling the mixture within a magnetic brush during the polishing process. This study describes the application of the ceramic particles for the magnetic abrasive polishing. The distribution of the magnetic abrasives attached on a tool varies with magnetic flux density and tool rotational speed. From the correlation between abrasive adhesion ratio in the tool and surface roughness produced on a workpiece, practical polishing conditions can be determined. A step-over for polishing a large sized workpiece is able to be selected by a S curve, and an ultrasonic vibration assisted MAP produces a better surface roughness and increases a polishing efficiency.

• Journal of Families and Better Life
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• v.4 no.2
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• pp.25-34
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• 1986

This study aimed to find out the suitable design of footwear cabinet. The questionnaire data from 1969 persons of 400 families about footwear cabinet showed following results. 1) The number of shoes was related with sex, age, occupation, family income, the number of family members and educational level of housewives. 2) The size of shoes in the range of 80% of the investigated shoes was 30cm of height, 30cm of length, and 10cm of width. 3) The satisfaction with footwear cabints was mainly decided by the size and space of the cabinet. 4) Umbrella, tools and shoe polish and brush were usually kept in the footwear cabinet as well as shoes. On the basic of the results above. The size of 108cm of length (20cm for umbrella), 35cm of width and 105cm of height is sugested as the desirable footwear cabinet for the General public housing scale apartment for 5 family members and this cabinet should have 5 divider and one flexible divider by 30cm which may be adjusted by 20cm.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.703-709
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• 2017

Korea Utility Helicopter(KUH) is a project to replace the aging helicopter presently being operated by the military with a domestic helicopter. The auxiliary power unit is a device that supplies emergency power to the system by an alternator installed when the main generator fails and the start motor converts the electrical energy of the battery into mechanical rotational energy to rotate the auxiliary power unit engine. With continuing power and operation, defects of the starting motor were found and improvements were carried out to solve it. In the failure mode analysis, the causes of possible defects were classified into 5 categories. Analysis of the 5 factors revealed that the main cause of defects is mechanical wear, which was found to be related to spring pressure. 250 tests were conducted through the theoretically determined pressure and regression analysis was performed with 4 sampling.The results showed that pressure was related to wear rate. In conclusion, early wear and breakage due to wear can be controlled through spring force and test showed the prediction of wear and the validity of the result were confirmed.

• Fashion & Textile Research Journal
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• v.16 no.1
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• pp.55-65
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• 2014

This study analyzes music visualization characteristics in modern fashion based on Wassily Kandinsky's music visualization theory. Alexander McQueen's 2014 Spring Ready-to-wear Collection (as inspired by Mondrian's paintings) was selected as the research subject. First, an analysis of Mondrian's paintings based on Wassily Kandinsky's theory shows that music visualization characteristics can be categorized into spatiality, mobility, and duality. Second, McQueen applied Mondrian's paintings to the overall design, structured the model's shape in the painting, or created patterns using colors and lines that introduced them in clothes; symbolic forms were also introduced as part of or a decorative factor of the clothes. Third, spatiality refers to the creation of a feeling of space through emptiness or fill using lines, colors, and shape. Musical atmosphere such as dissonance were expressed in clothing through the application of color contrast, lines and silhouette dynamics, and symbolic format and patterns by Mondrian. Fourth, mobility generally refers to motion caused by a certain stimulus. Mondrian expressed vibration, internal resonance, sound level in music that emphasized color irregularity, primary color contrast, and rough brush touches as well as free and organic patterns. McQueen expressed this with primary color contrast using different materials, rough touch based on texture, and pattern repetition through transformation. Fifth, duality generally refers to the artistic effect caused by overlap. Mondrian created a resemblance of dissonance and music through line and color as expressed through the duality of clothing design components based on the artistic sense of the designer.

• Journal of Korea Association of Health Promotion
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• v.2 no.1
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• pp.93-104
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• 2004

Purpose : This study was conducted to understand the health status and health behaviors of preschoolers to provide baseline data for developing health promotion programs. Method 'Parents of children attending day-care centers and guardians of preschoolers were recruited for the study. Data were collected from June to August2002 using a structured questionnaire. Result . Among 754 preschoolers, 17,3% were overweight, while 18.2% were underweight, while 15.9% and 23.2% were overweight and underweight respectively, among 85 children living with guardians. The most frequent infectious diseases that children have had previously were hand-foot-mouth disease, chicken pox, and measles. Current health conditions that children have frequently are respiratory disease and atopic dermatitis for bother groups. Only 54%-61% brush their teeth everyday at bedtime, 49%-54% wash their hands every time after returning home, 4.5%-8.8%wear bicycle helmets, 9,3%-11.1% use a child car seat, and 3.5%-8.1% eat fruits and vegetables five times a day, Children living with guardians were less likely toper form positive health behaviors compared with children in day-care centers. Conclusion 'Based on the study results, health professionals could plan and develop health promotion programs to change unhealthy behaviors of preschoolers targeting high-risk groups.

• Journal of Korean Academy of Nursing
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• v.34 no.1
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• pp.182-190
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• 2004

Purpose: This study was conducted to understand the health status and health behaviors of preschoolers to provide baseline data for developing health promotion programs. Method: Parents of children attending day-care centers were recruited for the study. Participating day-care centers were selected using a stratified sampling method. Data was collected from June to August 2002 using a questionnaire. Result: Among 754 preschoolers, 17.3% were overweight, while 18.2% were underweight. The most frequent infectious diseases that children have had previously were hand-foot-mouth disease (20.2%) and chicken pox (18.7%). Current health conditions that children have frequently are respiratory disease (28%) and atopic dermatitis (23.8%). Only 61% brush their teeth everyday at bedtime, 54.3% wash their hands every time after returning home, 8.8% wear bicycle helmets, 9.3% use a child car seat, and 8.1% eat fruits and vegetables five times a day. Children residing in the metropolitan area were more likely to have positive health behaviors, and children of parents with an advanced college level education were more likely to have positive health behaviors than those with only a high school level education. Conclusion: Based on the study results, health professionals could plan and develop health promotion programs to change unhealthy behaviors of preschoolers targeting high-risk groups.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.1
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• pp.603-608
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• 2018

Although the voltage-applied discharge method is most widely used in the semiconductor and display industries, periodic management costs are incurred because the method causes defects due to the absorption of ambient fine dust and causes emitter tip contamination due to the discharge. The emitter tip contamination problem is caused by the accumulation of fine particles in ambient air due to the corona discharge of the ionizer. Fuzzy ball generation accelerates the wear of the emitter tip and deteriorates the performance of the ionizer. Although a mechanical cleaning method using a manual brush or an automatic brush is effective for contaminant removal, it requires management of additional mechanical parts by the user. In some cases, contaminants accumulated in the emitter may be transferred to the wafer or product. In order to solve this problem, we developed an ionizer for a clean environment that can remove the pencil-type emitter tip and directly ionize the surrounding gas molecules using the tungsten wire located inside the ion tank. As a result of testing and certification by the Korea Institute of Machinery and Materials, the average concentration was $0.7572particles/ft^3$, the decay time was less than two seconds, and the ion valance was 7.6 V, which is satisfactory.

• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.1
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• pp.99-105
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• 2007

In clinical practice, air bubbles trapped in the pit and fissure may increase early loss of sealing materials for fracture, wear and microleakage. The purpose of this investigation was to examine the bubble behavior of pit and fissure sealant. The 140 replicas made of epoxy resin were used to this experiment. Following conditioning, light-polymerized sealants were applied and then exposed to the light source. After stereoscopic examination of standarized specimen by grinding, bubble behavior was analysed. The results obtained were as follows; 1. Ultraseal $XT^{(R)}$ plus grops irrespective of using time were higher than groups of $Helioseal^{(R)}$ with clinpro tip and metal tip in the frequency of bubble(p<0.05), 2. Ultraseal $XT^{(R)}$ plus old group was more than $Clinpro^{(R)}$, Teethmate $F-l^{(R)}$ and $Helioseal^{(R)}$ with brush tip in the number of bubble under 200 magnified cross section(p<0.05). 3. The widest mean area of bubble was shown in the Teethmate $F-1^{(R)}$. 4. No statistically significant difference of the frequency and the site of bubble between $Clinpro^{(R)}$ and $Helioseal^{(R)}$ groups(p>0.05).