• Journal of the Korean Wood Science and Technology
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• 제48권5호
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• pp.666-675
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• 2020

본 연구는 태백산맥을 기준으로 영동(고성군), 영서(홍천군), 영남(봉화군) 세 지역 간 소나무의 재질 차이 유무를 알기 위해 역학적 특성을 조사하였다. 측정한 역학적 성질은 압축강도, 경도 및 전단강도였다. 압축강도는 미성숙재에서 지역 간 차이가 없으며, 심재부와 변재부에서는 봉화, 홍천, 고성군 순으로 크게 나타났다. 경도는 횡단면에서는 봉화군이, 방사 및 접선 단면에서는 고성군이 크게 나타났다. 전단강도는 심재부에서는 차이가 없었으며, 변재부에서는 봉화군이 고성, 홍천군에 비해 높게 나타났다. 이는 지역 간 가도관장, 마이크로피브릴경각 차이에 의한 것으로 생각된다. 지역 간 재질특성의 차이 규명으로 국내산 소나무재를 효율적이고 선택적으로 사용하여 부가가치를 높이고, 또한 우수한 수형목을 선발하는데 활용될 수 있을 것으로 생각한다.

• 대한치과보철학회지
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• 제34권4호
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• pp.833-849
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• 1996

The material of choice for functional and esthetic reconstruction of maxillofacial defects is silicone. Silicone has appropriate physical properties for maxillofacial prosthesis but it has weak edge strength. Therefore, a proper combination of silicone and polyurethane sheet is recommended to improve this weakness. Various primers are also used to enhance the adhesive strength between silicone and polyurethane sheet. The purpose of this study was to determine the adhesive strength of silicone and polyurethane sheet. Silicone elastomer mixture was made by admixing MDX4-4210 elastomer (40%) and Silastic Medical Adhesive Type A(60%). This silicone elastomer mixture was attached to polyurethane sheet, using one of three different primers(1205, S-2260, or A-304), treated for 1, 2, 4, 6, and 8 hours. These were then polymerized in room temperature, dry-heat oven or microwave oven. Six specimens per each group, a total of 270 specimens were prepared for final test. The differences of T-peel bonding strengths were then determined by a test. The differences of T-peel bonding strengths were then determined by a test method that was recommended by American Society for Testing and Materials C794-80. The results were statistically analyzed using the ANOVA and Mutiple Range Tests(Tukey' HSD). The reults were as follow. 1. Type of primer, primer reaction time, and methods of polymerization showed significant correlation on the T-peel bonding strengths in adhesiveness between silicone and polyurethane sheet. 2. A-304 primer showed statistically higher in T-peel bonding strength than otehr type of primers except for the polymerization in microwave oven with reaction times of 2, 6 hours(p<0.05). 3. No significant differences in T-peel bonding strength were observed among the polymerization methods. 4. The effect of reaction time by the primer type and polymerization method showed statistically significant differences in bonding strength among different reaction times. And in most cases, reaction time of 1 or 2 hours showed higher T-peel bonding strength.

• Design & Manufacturing
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• 제8권2호
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• pp.23-29
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• 2014

Salt bath heat treatment is usually used but recently vacuum heat treatment is increased for the heat treatment of hot work die steels. The differences in two heat treatment processes were compared by testing the mechanical properties of heat treated products. With two different features of processes, mechanical properties such as hardness, tensile strength and impact strength of products show very different results. In this study salt bath heat treated products showed higher tensile strength and impact strength than vacuum heat treated products but hardness was not much different. These lower mechanical properties of vacuum heat treated products are due to differences in heating and quenching process.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1997년도 가을 학술발표회 논문집
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• pp.27-32
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• 1997

It was fond that the compressive and flexural strength of recycled concrete was decreased with increasing the content of recycled aggregate and the early compressive strength was also decreased with increasing Fly Ash level. In comparison with recycled concretes producing various sources, the trend were similar to those shown above, but the differences were minor. the development of Flexural strength in both concretes was similar, but the recycled concrete is lower in the ratio of flexural strength and compressive strength. The drying shrinkage of recycled concrete is increased with increasing the amount of recycled aggregate, particularly the maximum differences were reached between at 2 and 3 weeks.

• 말소리와 음성과학
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• 제6권2호
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• pp.97-106
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• 2014

The purpose of this study was to (1) establish a Korean adult normative data for Iowa Oral Performance Instrument, (2) investigate the characteristics of maximal tongue and lip strength and tongue endurance scores according to age and gender, and (3) examine the correlation of those scores. The results showed that there were no significant differences of gender in maximal tongue strength and tongue endurance scores. But there were significant differences of age in maximal tongue and lip strength and tongue endurance scores. The data will provide an important database for speech language pathology with the purpose of diagnosis and treatment of tongue and lip dysfunction.

• 대한물리의학회지
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• 제14권4호
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• pp.173-181
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• 2019

PURPOSE: This study examined the necessity of a musculoskeletal injury-prevention program for automobile parts manufacturing workers by assessing the body composition, muscle strength, and posture according to sex and age. METHODS: Two hundred eighty-two workers (men, 218; women, 64; mean age, 38.97 years; and mean work tenure, 10.29 years) participated in this study. They completed a questionnaire on their general characteristics, excluding personal identification codes. The participants were evaluated for body composition, muscle strength, and posture using InBody, a hand dynamometer, and the Image J program through photography, respectively. An independent t-test and one-way analysis of the variance were used for the comparisons according to sex and age, respectively. RESULTS: Significant sex-related differences in muscle strength and grip force were observed (p<.05). In addition, the left-side pelvic inclination was significantly higher in the female participants than in the male participants (p<.05). Significant age-related differences in the skeletal muscle mass and muscle strength were observed around 40 years (p<.05). Significant correlations were observed among the body composition (skeletal muscle and body fat masses), muscle strength, and posture (pelvic inclination; p<.01). CONCLUSION: Significant differences in pelvic inclination by sex and muscle strength by age were found, even in healthy workers. Additional posture and muscle strength measurements will be needed for workers who participate in the musculoskeletal injury prevention program because they are exposed to an incorrect posture for many hours or in many repetitive tasks.

• 대한정형도수물리치료학회지
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• 제24권2호
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• pp.59-67
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• 2018

Background: The purpose of this study was to investigate the effects of gluteus medius strength exercise on the ankle stability of high school student with chronic ankle sprains. Methods: A total of 30 participants were divided two groups. Experimental group was 15 participants applied gluteus medius strength exercise. Control group was 15 participants performing ankle strength exercise. This study was performed for 50 minutes per day, three a week for 6 weeks. All measurements were taken to a pre and post test. Strength was measured using Power Track ll. Balance was measured using Biodex balance system for Limits of Stability and Postural Stability. Ankle Stability was measured using Cumberland Ankle Instability Tool (CAIT). Results: In the case of gluteus medius strength, there were statistically significant differences between the experimental group and the control group. For ankle stability were statistically significant differences within the experimental group according to measurements taken by Limits of Stability, Postural Stability, and CAIT. A between group comparison showed a statistically significant difference for CAIT only. Conclusion: According to our measurements it appears that gluteus medius strength training was effective in benefiting muscular strength, balance and ankle stability among the physical education.

• 대한통합의학회지
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• 제10권3호
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• pp.247-256
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• 2022

Purpose : The purpose of this study was to investigate the effects of Kaltenborn-Evjenth (KE) joint mobilization of the distal radioulnar joints (RUJ) and proximal RUJ in distal radius fractures (DRFs) on range of motion (ROM), grip strength (GS), and patient-written wrist evaluation (PRWE) in each group once, thrice, or fivefold. Methods : Forty-two subjects participated in this study. We divided the subjects with DRFs into groups applying KE concepts RUJ mobilization once, thrice, and fivefold. The patients' ROM and GS were measured using a joint goniometer and dynamometer, respectively. Pain and function were also assessed using a PRWE. In the statistical analysis, all data were tested for normality using the Shapiro-Wilk test, and paired t-tests were performed for within-group before-and-after comparisons of each intervention. One-way analysis of variance was used for between-group comparisons of differences. All statistical significance levels were set at α=.05. Results : There were significant differences in the ROM in all three groups before and after the intervention (p<.05), but there were no significant differences between the groups. There were significant differences in the GS in the three groups before and after the intervention (p<.05), but there were no significant differences between the groups. In the pain part of the PRWE, all three groups had significant differences before and after intervention (p<.05), but there was no significant difference between the groups. In the functional part of the PRWE, there were significant differences in the three groups before and after intervention (p<.05), but no significant difference occurred between the groups. Conclusion : Based on the aforementioned results, there were no significant between-group differences in ROM, GS, and PRWE (pain and function) after the application of the K-E joint mobilization to DRFs once, thrice, and fivefold. Nevertheless, there were significant within-group differences in all the above.

• 한국가정과학회지
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• 제10권2호
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• pp.43-51
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• 2007

This study aims at looking into the differences of the adolescent's school adjustment of the high school first and second graders according to their school type, family background factors and family strength. Based on the results, this study is to identify the relative influences of those students' school type, family background factors and family strength factors on their school adjustment by gender. The conclusions of this study are as follows: First, adolescent's school adjustment shows some differences according to their school type and gender but does not exhibit any interaction effect. Second, the parent's educational levels don't show any difference on their school adjustment by both gender. Third, the most important predictor affecting adolescent's school adjustment is family strength factors in boys and girls all together.

• Journal of Ceramic Processing Research
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• 제19권5호
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• pp.419-423
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• 2018

A newly conceived geopolymer composite was fabricated by a combination of the geopolymer and polyurethane sponge. The density and porosity of hardened geopolymer composite, corresponded to different pore sizes of polyurethane sponge, exhibited no significant differences from each other. However, the mechanical behavior, the compressive strength and flexural strength, showed slight differences accordingly. Fracture of the geopolymer composite exposed to high compressive load was not observed from all specimens containing polyurethane sponge. The toughness enhancement of the geopolymer composite, due to spontaneous elasticity of polyurethane sponge, crack spread, and crack diffraction, was identified through the stress-strain curve and microstructure of fracture surface. The newly designed geopolymer composite having a 3-dimensional sponge skeleton showed relatively higher flexural strength of 8.0 MPa than other conventional geopolymer composites.