• Elastomers and Composites
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• 제45권2호
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• pp.94-99
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• 2010

자동차용 내외장재로 사용하는 열가소성 엘라스토머(thermoplastic elastomer, TPE)로 제조한 시험편 표면에 340 nm의 자외선을 총 $2500\;kJ/m^2$ 조사하였다. 자외선 조사 후 검정 시험편 표면은 뿌옇게 변했다. 노화 전후 시험편 표면에 있는 물질을 채취하여 GC/MS로 분석하였으나 특이한 점이 발견되지 않았다. 노화된 시험편의 표면에서 잔크랙이 다수 발견되었다. 노화된 시험편의 백화 현상은 노화된 표면을 솔질하거나 불로 지지면 사라졌다. 솔질이나 불로 지진 후에는 표면에 있던 잔크랙이 사라졌다. 노화 전후의 시험편과 노화된 시험편 표면을 솔질 혹은 불로 지진 후의 시험편을 영상 분석기, SEM, EDX, ATR 등으로 분석하여 비교한 결과, 솔질이나 불로 처리한 후 제거된 백화 현상은 솔질이나 불에 의한 가열로 TPE의 구성 성분 중 하나인 폴리프로필렌이 잔크랙을 메웠기 때문으로 설명할 수 있다.

• 소성∙가공
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• 제32권4호
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• pp.173-179
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• 2023

In this study, the age-hardening behavior and tensile properties of a cast AZ91-0.3Ca-0.2Y (SEN9) alloy are investigated and compared with those of a commercial AZ91 alloy. Even after homogenization heat treatment, the SEN9 alloy contains numerous undissolved secondary phases, Al₈Mn₄Y, Al₂Y, and Al₂Ca, which results in a higher hardness value than the homogenized AZ91 alloy. Under aging condition at 200 ℃, both the AZ91 and SEN9 alloys exhibit the same peak-aging time of 8 h, but the peak hardness of the latter (86.8 Hv) is higher than that of the former (83.9 Hv). The precipitation behavior of Mg₁₇Al₁₂ phase during aging significantly differs in the two alloys. In the AZ91 alloy, the area fraction of Mg₁₇Al₁₂ discontinuous precipitates (DPs) increases up to ~50% as the aging time increases. In contrast, in the SEN9 alloy, the formation and growth of DPs during aging are substantially suppressed by the Ca- or Y-containing particles, which leads to the formation of only a small amount of DPs with an area fraction of ~4% after peak aging. Moreover, the size and interparticle spacing of Mg₁₇Al₁₂ precipitates of the peak-aged SEN9 alloy are smaller than those of the peak-aged AZ91 alloy. The homogenized AZ91 alloy exhibits a higher tensile strength than the homogenized SEN9 alloy due to the finer grains of the former. However, the peak-aged SEN9 alloy has a higher tensile elongation than the peak-aged AZ91 alloy due to the smaller amount of brittle DPs in the former.

• Asian Pacific Journal of Cancer Prevention
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• 제15권22호
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• pp.9891-9898
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• 2014

Background: This study was planned in an attempt to develop scales for the assessment of fatigue in pediatric oncology patients aged 13-18 and also for their parents. Materials and Methods: In collecting the study data, we used the Child and Parent Information Form, Visual Fatigue Scale, Scale for the Assessment of Fatigue in Pediatric Oncology Patients Aged 13-18 and the Scale for the Assessment of Fatigue in Pediatric Oncology Patients Aged 13-18 for Parents. We also used Pearson correlation analysis, Cronbach alpha coefficient, factor analysis and ROC analysis for the study data. Results: In this study, the total Cronbach alpha value of the parent form was 0.99, the total factor load was 0.72-0.94 with 95% the total variance being explained. The cutoff point of the parent form is 73 points. The total Cronbach alpha value of the child form was 0.99, the total factor load was 0.82-0.95, with 89.4% of the total variance being explained. The cutoff point of the child form was 75.5 points. Conclusions: This study suggests that the Scale for the Assessment of Fatigue in Pediatric Oncology Patients Aged 13-18 and the Scale for the Assessment of Fatigue in Pediatric Oncology Patients Aged 13-18 for Parents are valid and reliable instruments in assessing the fatigue symptoms of children in Turkey.

• KIEE International Transactions on Electrophysics and Applications
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• 제3C권2호
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• pp.59-65
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• 2003

Electrical properties such as permittivity and tan$\delta$ of unaged (control) and aged (72 h at 18$0^{\circ}C$) mica/epoxy composites of 130 ${\mu}{\textrm}{m}$ thickness were measured and their surface conditions were characterized using scanning electron microscopy (SEM), Fourier transform infrared (FTIR), electron spectroscopy for chemical analysis (ESCA), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Both permittivity and tan6 of control specimens were higher than those of short-time aged specimens. FTIR results show a new peak at 1710 $cm^{-1}$ / for short-time aged specimens, originating from carbonyl group formed by the oxidation reaction during the aging process. ESCA results show that the binding energy at 532.9 eV representing the singlet state of oxygen ( $O_{1s}$) decreases by 13.7%, whereas that at 534.6 eV increases by 13.7%. Glass transition temperatures of control and short-time aged specimens are observed to be 95.4$^{\circ}C$ and 113.4$^{\circ}C$, which increase with the increase of aging time. TGA results indicate that the control specimens contain a smaller amount of volatile components than the short-time aged specimens.s.

• 한국의류학회지
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• 제45권3호
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• pp.477-494
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• 2021

This study examined four subjects with close to average body-size values in four stages based on the average BMI value of middle-aged women aged 45 to 59 years. The first experimental pants was developed with two kinds of educational materials pants pattern. After using a clothing-suitability evaluation to identify problems, a pants pattern suitable for the body shape of middle-aged women was developed by modifying and supplementing the initial design. The fit assessment revealed that pattern A had a problem with wrinkles in the hip and thigh areas due to the long crotch length, and pattern B had a short bottom length, which caused the bottom to curl in toward the groin or for the bottom to stick at the hips. The second experimental pants was developed to address these issues and overall satisfaction with the dimensions was higher than for the first educational pattern. The proper front and rear length extensions satisfied movement functionality and appearance requirements, and increasing the gradient of the back centerline-rather than expanding the width of the back crotch-improved the functionality.

• 한국식생활문화학회지
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• 제21권6호
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• pp.670-678
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• 2006

The objectives of this study were to develop calcium enriched menu for the aged and to investigate physicochemical characteristics and consumer acceptances of the menus. four kinds of the menu were developed with emphasis on calcium enriched food materials of red pepper leaves seasoned vegetables for menu1, shrimp for menu2, anchovy for menu3, seaweed for menu4. one portion of calorie, polysaccharide, protein, fats and calcium for the aged were calculated as 567kcal, 92.8g, 21.3g, 12.6g 223.1mg, respectively based on the recommended daily allowances for adults. Calcium content increased in the lowest value of all(p<0.05). The hunter lightness(L) values of barely rice in menu 1, radish soup in menu 1, chopped roast chicken in menu 4 and radish salad in menu 2 had significantly the highest values of all(p<0.05). The calcium enriched menus for the aged were successfully developed and these data could be used as basic informations for the improvement in health and life of the aged.

• Imaging Science in Dentistry
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• 제31권4호
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• pp.193-197
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• 2001

Purpose : To determine whether there is a relationship between abnormal temporomandibular joint radiographic findings and age or gender in a sample of preorthodontic patients. Materials and Methods : Individualized corrected sagittal tomographs of 188 temporomandibular joints in 94 preorthodontic patients, aged 11 to 29 years, were taken and viewed by an observer blinded to clinical records. The study population was divided into 2 aged groups (11-15 years and 16-29 years) for comparative purposes. Temporomandibular joint radiographic findings were classified as normal or abnormal. Results: There was no difference in ratio of abnormal to normal findings between the both aged groups. The frequency of osseous abnormalities was similar with that of abnormalities of condylar position. Abnormalities in CP and JS were most frequent in all aged groups. Conclusion : There is no significant difference between ages or genders for temporomandibular joint radiographic abnormalities.

• The Korean Journal of Ceramics
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• 제4권1호
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• pp.28-32
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• 1998

This paper reports on photoluminescence (PL), luminescence decay curves, and compositional analysis of porous silicon(PS) which is aged under air ambient by Fourier transform infrared vibrational spectroscopy (FTIR) and by Auger electron spectroscopy (AES). Porous silicos which has been aged under air ambient yields two PL band structures, i.e. blue/violet PL and red PL. The evolution of a blue/violet band is pronounced, especially for thin PS film which is prepared in dilute HF solution. The blue/violet PL band has been observed initially to increrase rapidly with aging, then saturated with further atmospheric aging. The ambient air aged PS exhibits a fast decay time of sub-nanosecond at room temperature and shows appreciably faster decay time than that at 20K. Atmospheric aging of this thin blue/violet luminescing PS yield non-stoichiometric oxide judging from the vibrational spectra of Si-O and AES analysis.

• 한국재료학회지
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• 제12권6호
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• pp.436-441
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• 2002

Effect of Sn addition on the stress corrosion cracking(SCC) resistance of the Al-Cu-Mn cast alley was investigated by C-ring teat and electrical conductivity measurement, The electrical conductivity and SCC resistance increased by Sn addition. The alley containing 0,10%Sn showed maximum electrical conductivity and the best SCC resistance. At the same composition, the electrical conductivity and SCC resistance increased from peak aged condition to ever aged condition. The PFZ and coarse precipitates along the grain boundary were observed from TEM micrographs. The fracture mode of the alloy was confirmed as intergranular type and showed brittle fracture surface. The SCC mechanism of the alloy was concluded as the anodic dissolution model, The maximum hardness was increased from 130Hv in the Sn-free alloy to 156Hv in the 0.10%Sn added alloy.

• 한국의류산업학회지
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• 제21권5호
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• pp.618-626
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• 2019

This study conducted basic studies to develop electromagnetic wave shielding maternity wear. We investigated electromagnetic wave shielding fabrics and products as well as surveyed actual wearing states for pregnant women aged 35 to 44 and women who gave birth within the past one year. Available electromagnetic wave blocking products for pregnant women were blankets, aprons, maternity belts, and underwear. These only cover the abdomen and it was hard to find out electromagnetic waves shielding maternity wear, which can enhance functionality and complement the body shapes of pregnant women. The aged mother responded pregnancy delay was mostly attributable to late marriage, career, financial difficulty and health problems. Major health threats to babies were high stress levels during pregnancy, followed by electromagnetic waves from electronic devices. They prioritized physical activity, design, functionality and safety when wearing maternity wear. When purchasing maternity wear, they emphasized design, price, materials and size. The most preferred clothing was one-piece dress; consequently, only 11.1% of them were satisfied with the quality of maternity wear with complaints mostly about design and price. A total of 63% of respondents tried to protect themselves from electromagnetic waves. Most aged mothers showed a positive intention on purchasing electromagnetic waves blocking maternity wear for babies with concerns dealing with safety of materials, prices, ease of laundry, and body complementing design.