• 한국소음진동공학회논문집
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• 제16권6호
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• pp.609-618
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• 2006

This study is undertaken for the vibration analysis of tapered thick plate with concentrated mass on elastic foundation. The boundary condition of the plate is analyzed with the 4-sides simply supported and 4-fixed basis. This study find out the frequency following the change in size for each foundational variable on Pasternak foundation, one of the two-parameter elastic foundation parameter that considered the shear layer to the Winkler foundation parameter. The concentrated mass is applied with the consideration of mass of the entire plate, and the change of frequency is studies on each location with the consideration of reacting for the three locations for concentrated mass. And, in order to find out the change of frequency on the thickness of the plate, it considered tapered ratio that linearly changes depending on the length of the plate with the thickness of the plate in x-direction, and the tapered ratio has changes with 4 types ($\alpha$=0.25, 0, 5, 0.75, and 1.0). For the interpretation, the program using finite element method (F.E.M.) is used and the element coordination is used the 8-node serendipity element. Therefore, the purpose of this study is to find out the characteristics of plate vibration under the mechanica vibration or external vibration factor to facilitate as the basic data of the design to secure the stability.

• 공업화학
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• 제9권5호
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• pp.715-718
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• 1998

본 연구에서는 수직섬유의 길이가 서로 다른 삼차원 유리직물을 보강재로 사용하고, 매트릭스 수지로 비스페놀 타입 비닐 에스테르 (bisphenol type vinyl ester)를 사용하여 hand lay-up을 이용해 복합재료 (3D composites)를 제조하였다. 삼차원 유리직물의 수직섬유의 길이가 복합재료의 기계적 물성에 미치는 영향을 three-point bending test, flatwise compression test를 통해 조사하였다. Short-beam test법 통하여 복합재료에서의 섬유와 매트릭스 수지간의 계면접착강도를 나타내는 층간 전단강도를 구하였다. 시험 결과를 통하여 수직섬유의 길이가 복합재료의 기계적 물성 및 층간 전단강도에 많은 영향을 미침을 알 수 있었다.

• 반도체디스플레이기술학회지
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• 제18권4호
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• pp.96-99
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• 2019

Atomic layer etching (ALE) is one of the most promising techniques in the semiconductor industry. Since ALE has to be precisely controlled on the angstrom scale to achieve ideal results, an in-situ analysis of the processes is highly required. In this regard, we found during ALE experiments with in-situ monitoring with an ellipsometer that changes in the substrate temperature affected the refractive index of a material, leading to changes in measured film thickness. In addition, more ideal ALE results could be achieved by keeping the substrate temperature constant.

• 한국융합학회논문지
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• 제10권7호
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• pp.267-279
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• 2019

본 연구는 지실추출물과 나린진의 햇빛으로부터 피부 보호 및 주름개선에 대한 연구를 하였다. HR-1(무모쥐)에 햇빛을 조사하여 상피 두께의 변화와 진피의 90% 정도를 차지하는 콜라겐 섬유의 변화를 확인하였다, 콜라게나아제의 억제 효능도 주름에 중요하게 작용하므로 같이 확인하였다. 실험은 나린진과 지실추출물을 사용하여 효능을 검증하였다. 첫째: 지실과 나린진의 성분을 분석하였다. 둘째: DPPH로 항산화 능력을 확인하였다. 셋째: 콜라겐의 변화를 측정하였다. 연구 결과로 지실추출물 및 나린진이 피부 상피두께 억제와 피부의 콜라겐 두께가 상승하였고 콜라겐 분해 효소 억제 및 주름이 대조군에 비하여 감소되었으며 유의한 차이가 나타났다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제48권4호
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• pp.219-224
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• 2022

Objectives: There have been few studies to date on the residual effect of bisphosphonate. This study investigated the radiographic changes of mandibular cortical thickness upon bisphosphonate drug holiday. Materials and Methods: This retrospective study includes 36 patients diagnosed with MRONJ (medication-related osteonecrosis of the jaw) at Ajou University Dental Hospital in 2010-2021. All patients stopped taking bisphosphonate under consultation with the prescribing physicians. Panoramic radiographs were taken at the start of discontinuation (T₀), 12 months after (T₁), and 18 months after (T₂) discontinuation of bisphosphonate, respectively. Mental index and panoramic mandibular index were calculated using Ledgerton's method. Paired t-tests were used to analyze differences over time. Results: The difference in indices (mental index and panoramic mandibular index) between T₀ and T₁ was not statistically significant (paired t-test, P>0.05). However, the difference in these indices between T₁ and T₂ was statistically significant (paired t-test, P<0.05). Conclusion: The cortical thickness of the mandible decreased in the late stage (after 18 months) as observed by panoramic radiograph.

• 한국의류학회지
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• 제23권5호
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• pp.726-736
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• 1999

The purpose of this study was to obtain the basal information for standard amount of clothing weight indoor climate and working condition with investigating seasonal changes of skin temperature and factors influencing on that in Koreans. Forty eight subjects in 5 age groups(6-11, 12-19, 20-44, 45-64, 65-76 years old) with both sexs were measured skin temperature indoor climate clothing microclimate clothing weight and skinfold thickness in neutral condition in each month throughout the year. The results obtained are summarized as follows : 1. Indoor climate koreans felt comfortable ranged 18.1-28.7$^{\circ}C$ and 51-74%RH. 2. Temperature inside the clothing ranged 30.8-32.3$^{\circ}C$ in males and 31.0-32.5$^{\circ}C$in females. There was a significant difference in temperature inside the clothing among age groups : That of 6019 age group was slightly higher than that at 45-76 age group. 3. Total clothing weight changed with season and increased in order of summer autumn spring and winter Total clothing weight of 65-76 age group was significantly greater on January and February. Breast skinfold thickness showed the smallest value in summer and the largest value in winter year. In addition to breast and abdomen skinfold thickness were larger in 45-67 age group while thigh skinfold thickness was larger in 6-19 age group. Skinfold thickness in females showed the smallest value in spring summer and the largest value in autumn and winter. In addition to triceps and suprailliac skinfold thickness were larger in 45-64 age group while thigh skinfold thickness was larger in 12-19 age goup. 5. Temperature of the lower limbs(hand, thigh. leg, and foot) showed significant correlation with the indoor temperature humidity inside clothing and total clothing weight. Temperature of the torso(breast and abdomen) showed significant correlation with the temperature inside clothing in all subjects. Abdomen skinfold thickness of all age group in male showed significant correlation with the abdomen skin temperature. triceps suprailliac and thigh skinfold thickness of 6-11 age group in female showed significant correation the upperarm abdomen and thigh skin temperature. Consequently clothing mdicroclimate total clothing weight and skinfold thickness showed significant difference in season sex and ages and had a slight effect on skin temperature.

• 한국발생생물학회지:발생과생식
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• 제17권4호
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• pp.427-434
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• 2013

The histological changes in the Ussurian bullhead, Leiocassis ussuriensis, and the Korean bullhead, Pseudobagrus fulvidraco, were observed during the early period of growth. The retinas size of both species increased in the 9 days post-hatching (DPH) (p<0.05). In the just-hatched Ussurian bullhead, the retina already consisted of six layers: the epithelial layer, ganglion cell layer, inner nuclear layer, inner plexiform layer, outer limiting membrane layer, and rod and cone layer. The Korean bullhead had the same components. At 50 DPH, the thickness of the retina was $538.0{\pm}7.19{\mu}m$ in the Ussurian bullhead and $558.9{\pm}9.44{\mu}m$ in the Korean bullhead. The relative thickness of each layer of the retina did not differ significantly in the two species. Although the growth of the Korean bullhead's retina was faster, the relative thickness of each layer in the retina did not change during early development. After hatching, some parts of the tissue gradually became denser. Immediately after hatching, the kidney and midgut epithelium of the Ussurian bullhead and Korean bullhead were already formed and grew gradually thereafter. From 0 DPH to 30 DPH, the nuclear height in the midgut epithelium did not differ significantly between the two species, but at 50 DPH, it was $11.4{\pm}2.45{\mu}m$ in the Korean bullhead and $9.9{\pm}2.13{\mu}m$ in the Ussurian bullhead. During the experimental period, the major axes, minor axes, surface areas, and volumes of the proximal tubule cells in the kidney did not differ significantly between the two species. Thus, the early histological development of the Ussurian bullhead is similar to that of the Korean bullhead.

• 대한치과교정학회지
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• 제25권2호
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• pp.201-208
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• 1995

교정치료시 보다 효과적인 치아 이동을 위한 한 방법으로 최근 자석 사용이 고려되고 있다. 영구자석의 체적 변화가 자력에 미치는 영향을 파악하고자 한 쪽에 한 개의 자석을 고정하고 반대쪽 자석의 두께나 넓이를 일정한 비율로 증가시키면서 양측 간에 나타나는 자력을 비교 연구한 결과 다음과 같은 결과를 얻었다. 1. 두께를 증가시킨 경우에는 자력이 증가하였으나 넓이를 증가시킨 경우 자력이 오히려 감소하였다. 2. 체적 증가에 따른 자력의 증감은 대수함수 분포 양상을 나타내었다. 3. 두께 증가로 체적을 변화시킨 경우, 같은 두께라도 처음부터 크게 제작한 자석이 작은 자석을 여러 개 합한 것보다 큰 자력을 보였다. 본 연구 결과 구강내에서 자력을 증가시키기 위해서는, 마주보는 자석면은 같게 유지하면서 넓이 증가보다는 두께를 증가시키는 방법이, 그리고 처음부터 두꺼운 자석을 사용하는 것이 보다 효율적임을 알 수 있었다.

• 콘크리트학회논문집
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• 제25권5호
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• pp.573-581
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• 2013

이 논문은 강섬유보강콘크리트와 GFRP (glass fiber reinforced polymer)사이의 부착 특성을 조사하기 위한 실험적 연구를 수행하였다. 실험 주요 변수로는 보강근 지름, 섬유혼입량, 피복두께 및 콘크리트의 압축강도를 설정하였다. 부착파괴는 주로 콘크리트 피복에서의 쪼갬으로 인하여 유발되며, 이러한 콘크리트의 쪼갬파괴는 보강근과 콘크리트 사이의 변형 차이로 유발되는 인장력때문에 발생한다. 따라서, 보강근과 콘크리트 사이의 부착파괴를 방지하기 위하여, 콘크리트 피복부위의 인장강도를 향상시켜야 한다. 실험결과를 살펴보면, 섬유혼입량 증가는 부착강도를 크게 향상시키고 있으며, 피복두께는 최종 파괴모드를 변화시킴을 확인할 수 있었다. 보강근의 지름 또한 최종 파괴모드를 변화시킴을 확인할 수 있었다. 일반적으로 보강근의 지름은 부착특성에 영향을 미치는 것으로 알려져 있으나, 섬유혼입량은 부착특성에 큰 영향이 없는 것으로 알려져 있다. 콘크리트 압축강도의 증가는 보강근과 콘크리트 사이의 부착강도를 증가시켰으며, 이는 압축강도의 증가가 직접적으로 인장강도의 증가를 유발하기 때문이라고 판단된다.

• Asian-Australasian Journal of Animal Sciences
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• 제28권6호
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• pp.840-846
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• 2015

The objective of this study was to investigate the effects of dietary corticosterone on egg quality. For 2 weeks hens received either control or experimental diet containing corticosterone at 30 mg/kg diet. Feed intake and egg production were monitored daily, and body weight measured weekly. Egg weights and egg quality were measured daily. Corticosterone treatment resulted in a remarkable increase in feed intake and sharp decrease in egg production compared with control (p<0.05) whereas body weight remained unchanged. Decreased albumen height, but no changes in egg weight, led to decreased Haugh unit (p<0.05). Corticosterone caused elevated eggshell thickness (p<0.05) without altering weight and strength, suggesting possible changes in shell structure. Yolk color and redness were increased by corticosterone (p<0.05) but lightness and yellowness were either not changed or inconsistent over the time period of measurements. Increased concentrations in plasma were also found for corticosterone, glucose, cholesterol, creatinine, uric acid, albumin, aspartate aminotransferase, creatine kinase, lactate dehydrogenase, total protein, and amylase (p<0.05), suggesting that corticosterone increased protein breakdown, renal dysfunctions and pancreatitis. Together, the current results imply that dietary corticosterone affects egg quality such as yolk colors and shell thickness, in addition to its effects on feed intake and egg production.