• Elastomers and Composites
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• v.28 no.1
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• pp.13-21
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• 1993

Polyurethane resin was especially mixed with polybutadiene rubbers which had each other different molecular structures and functional groups. Liquid and cure properties were tested experimentally for mixtures. Viscosity of mixtures and drying time were influenced by solubility of thinner and reactivity of rubber. Adhesive strength represented maxium at rubber content $15{\times}22%$ (Wt. % ), and rapidly decreased over 25%. DBTDL(di-n-butyltindilaurate) showed the longest stroage stability.

• Journal of the Korean Institute of Navigation
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• v.14 no.1
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• pp.9-19
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• 1990

Microwave absorbers for X-Band RADAR have been designed and fabricated trialy both in sheet and paint types, as a result of which the relative bandwidth of nearly 8% in both cases has been obtained under the tolerance limits of the reflection coefficients lower than -20dB. The matching thickness becomes 1.36 to 1.56mm which is significantly thinner than that of the conventional ones. Furthermore, it was shown that the microwave absorbing characteristics vary in accordance with the density and the mixing ratios of the materials constituting absorbs.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.105-108
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• 2001

In this paper, comparing and analyzing the distribution of brightness as domestic lamps and Japanese products go thinner and lighter, we set an effective design standard. By comparing and analyzing the feature, brightness, chromaticity and uniformity of domestic LGPs and Japanese products, early home-manufacturing and stabilization in home-manufacturing are possible. By comparing and analyzing the distribution of brightness as sheets are varied, we can design an ideal sheet composition.

• Korean Journal of Remote Sensing
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• v.4 no.1
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• pp.1-16
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• 1988

Multiyear ice is quite thick in general, and it needs to be distinguished from thinner types of ice because it represents a severe navigational hazard. Here, models are described for the radar backscatter from multiyear sea ice, based on simple scattering layers. Under cold conditions, the radiative transfer volume-scatter model can describe the backscattering from multiyear ice for frequencies higher than about X-band, while the surface scattering contribution has to be included for lower frequencies. A simple semi-empirical model is shown to be a good approximation to the radiative transfer model in describing the volume scattering from multiyear ice.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.21 no.2
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• pp.165-179
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• 1991

This study was performed to understand the irradiation effects on the mandibular condyle and mandibular growth in developing white rats. Forty eight white male rats of the Sprague-Dawley strain aged 4 weeks, were devided into two groups; control group and experimental group. A single target dose of l0Gy of radiation was given to the mandibular condylar area and the observations of the photo analysis, radiologic, histopathologic and immunohistochemical study revealed as follows; 1. Animals killed one week after irradiation showed lesser increase in body weights, no difference in photo analysis and decreased thickness of cartilagenous layers of the condyle than the control group. 2. Two weeks after irradiation the weight increases were almost same in both irradiated and control groups and in photo analysis, the distance from Mental Foramen to Incisal tip (Mf-It) was longer than the controls. Repair processes were taken place in irradiated group, but the cartilagenous layers were thinner than the controls. 3. By the third week after exposure further repair was seen in the trabeculae and the distance from Condylion to Mandibular plane (Cd-Cd') was longer than the controls and the weight increases were almost same as the controls. 4. At 4 weeks after irradiation the cells of proliferating zone repaired to almost normal findings, but the cartilagenous cell layers were still thinner than the control animals. In photo analysis, the distances from Menton to Anterior Notch (Me-An), from First Molar to Mandibular plane (Fm-Fm') were shorter and the weight increases were lesser than the controls. 5. In the S-100 antibody, the positive cells were increased in number, but decreased reactivities were seen at the proliferating zone of the irradiated groups. In the Monoclonal Anti-Proteoglycan antibody and Type Ⅰ collagen antibody, the irradiated groups showed little decreased number of positive cells and in the Type Ⅱ collagen antibody, the differences between irradiated and control groups were undetectable in immunohistochemical study.

• Journal of the Korean Ceramic Society
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• v.46 no.1
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• pp.86-93
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• 2009

The crack formation and the resistance of ITO film on PET substrate with a thickness of 20 nm were investigated as a function of strain. The onset strain for the increase of resistance increased with increasing strain rate, suggesting the crack initiation is dependent on the strain rate. Electrical resistance increased at the strain of 1.6% at the strain rates below $10^{-4}/sec$ while it increased at ${\sim}2%$ at the strain rates above $10^{-3}/sec$. The critical strain at which the cracks were formed is close to the proportional limit. Upon loading, the initial cracks perpendicular to the tensile axis were observed and propagated the whole sample width with increasing strain. The spacing between horizontal cracks is thought to be determined by the fracture strength and the interfacial strength between ITO and PET. The crack density increased with increasing strain. However, the effect of the strain rate on the crack density was less pronounced in ITO/PET with 20 nm ITO thickness than ITO/PET with 125 nm ITO thickness, the strength of ITO film is thought to increase as the thickness on ITO film decreases. The absence of cracks on ITO film at a strain as close as 1.5% can be attributed to the compressive residual stress of ITO film which was developed during cooling after the coating process. The higher critical strain for the onset of the resistance increase and the crack initiation of ITO/PET with a thinner ITO film (20 nm) can be linked with the higher strength of the thinner ITO film.

• The Korean Journal of Community Living Science
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• v.13 no.3
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• pp.69-80
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• 2002

This study was conducted to investigate the relationship among body image Perception, eating behavior and health status in young females. The survey was carried out by self-questionnaires for 293 female high school students(HS) and 164 female college students(CS) living in Daegu and suburbs of Daegu. For the perception of body image, 9-grade body figure drawings were used based on average Korean body size. EAT-26 and Rosenberg Self-Esteem Scale were used to measure the tendency of eating disorder and self-esteem. It appeared that 40.5% of the subjects were off the normal range of body weight; especially 34.2% of the subject were underweight. The subjects' perception about current body image was within normal range. Almost of all the subjects believed that the ideal body image was thinner than their own current body image, and they wanted to be thinner than their current body image. The change of eating behaviors related to weight control of CS was significantly higher than that of HS students. EAT-26 score, self-esteem score, and subjective health status score were no difference between groups. The cut-off point of the eating disorder in this study was equal to or greater than 20 in EAT-26 score. The rates of the eating disorder were very high as 9.6% of HS and 8.5% of CS. Eating disorder was positively correlated with BMI, current body image, dissatisfaction of body image and the change score of eating behavior. But eating disorder was negatively correlated with health status. From the results of this study, we suggested that one of causes related to the eating disorder behaviors in adolescent females was resulted from misperception about ideal body image. There is a great need to provide nutrition educations concerning appropriate perception of body image and weight control among adolescent females.

• Physical Therapy Korea
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• v.18 no.3
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• pp.8-15
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• 2011

Abdominal muscle plays a crucial role in postural control and respiration control. However, thickness of abdominal muscle in the paretic side of a hemiplegic patient has not been reported in previous studies. The purpose of this research was to compare lateral abdominal muscle thickness between the nonparetic and paretic side in patients with chronic stroke using rehabilitative ultrasound imaging. Twenty two patients with chronic stroke participated in this study. Absolute thickness of transversus abdominis (TrA), internal oblique (IO) and external oblique (EO) was measured at the end of inspiration and expiration during quiet breathing, and relative thickness was calculated (thickness of each muscle as a percentage of total muscle thickness). Ultrasound imaging was recorded three times and the average value was determined for statistical analysis. Differences in absolute and relative lateral abdominal muscle thickness between the nonparetic and paretic side were assessed with paired t-tests. Absolute muscle thickness of the paretic side TrA was thinner than that of the nonparetic side at the end of inspiration and expiration during quiet breathing. Relative muscle thickness of the paretic side TrA was thinner than the paretic side only at the end of expiration during quiet breathing (p>.05). Therefore, it is necessary to strength TrA in patients with chronic stroke during physical therapy intervention. Further study is needed whether physical therapy intervension will induce TrA thickness in patients with chronic stroke in prospective study design.

• Korean Journal of Community Nutrition
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• v.10 no.6
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• pp.930-942
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• 2005

This study was performed to investigate body image perceptions of women about themselves and their preschool children and also to investigate the relationship between these perceptions. Subjects were 545 women and their children (279 boys and 268 girls) residing in Daejeon city. $67.7\%$ of women were classified as normal group, $18.6\%$ as overweight group, and $13.8\%$ as underweight group by BMI. $68.5\%\;and\;78.7\%$ of their boys and girls, respectively, were classified as normal group, $22.4\%\;and\;16.4\%$ as overweight group, $9.1\%\;and\;4.9\%$ as underweight group by WLI. Women made relatively accurate judgments on their current body sizes and selected their body images as the most desirable one. But they preferred plumper figures for their children and failed to perceive their overweight children as overweight. While $74.7\%$ of women wished to be thinner, $81.1\%$ of them wished their children to be fatter. Women spending less then 100 thousand won and more than 500 thousand won as monthly food expenses and having only one child perceived their children's current body sizes the lowest and the highest, respectively. Women wished boys to be fatter than girls. Their current body sizes were correlated positively with the children's current body size (p < .01), and their healthiest, attractive, and 'wish' figures were correlated positively with children's current, healthiest, attractive, and 'wish' figures (p < .05- p < .01). Body size dissatisfaction (wish to be thinner) and BMI of women were correlated negatively with children's healthiest and attractive figures (p < .01). These findings suggest that in order to correct the women's body image misperceptions and to prevent childhood obesity, mother's perception about healthy body images for themselves and their children need to be included in nutrition education. Also, it is necessary to assist mothers to understand the relationship of body size and weight status with the risk of chronic disease which might appear later in their children's life. (Korean J Community Nutrition 10(6) : $930\∼942$, 2005)

• Journal of Welding and Joining
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• v.21 no.1
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• pp.107-113
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• 2003

Joining of $Si_3N_4$ to $Si_3N_4$ with crystallized glass solder was studied. $SiO_2-Al_2O_3-MgO$ glass with $P_2O_5$ as a crystallizing reagent was used as a solder. To improve the hish temperature toughness of joined specimen, two stage heat treatment was applied to Joined sample for the crystallization of joined layer, Two factors, i.e. thickness of soldered layer and crystallization were taken and thier effects on joining strength were investigated by a SEM-EDX observation of joined interface and bending strength both at room and elevated temperatures. Obtained results are summarized as follows: (1) Nitrogen diffused from $Si_3N_4$ to solder during the Joining process. Average amount of nitrogen in soldered layer depended on the thickness of the soldered layer and increased with decrease of the thickness. (2) Joining strength of the specimen having a thinner soldered layer was stronger than that of thicker layer. This can be mainly attributed to the difference of the nitrogen content in the soldered layer. (3) Higher content of nitrogen in solder brought forth higher viscosity of the solder. Hence the crystallization of the solder become more difficult in thinner layer of the solder than thicker one. (4) Thus, the effect of crystallization was evaluated mostly by the thicker layer specimen. Crystallization of soldered layer improved markedly the fracure strength of joining at higher temperatures than the softening temperature of glass solder.