• 농업생명과학연구
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• 제46권1호
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• pp.35-41
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• 2012

공진주파수 모드를 이용하는 비파괴 평가기술법을 닥나무를 소성온도별(600, 800, 1000, $1200^{\circ}C$)로 제조한 우드세라믹에 적용하였다. 공진주파수 및 동적 탄성계수는 소성온도가 증가할수록 증가하였다. 동적 탄성계수 및 정적 휨 탄성계수와 휨강도사이에는 밀접한 상관관계가 나타났다. 따라서 공진 주파수 모드를 사용하는 동적 탄성계수측정은 소성온도에 따라 제조된 우드세라믹의 휨강도를 예측하는 비파괴 평가 방법으로 유용할 것으로 판단된다.

• 지식경영연구
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• 제19권4호
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• pp.39-58
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• 2018

This study explores the effects of business consulting on the business performance of firms by using a unique survey for various industry sectors in Korea. We attempt to build a consulting model that shows the structural relationship between consulting factors and consulting performance. Moreover, through the consulting model, we conduct the analysis of elasticity of consulting factors and the group analysis based on firm age. First, the findings show that all consulting factor has a positive impact on the consulting performance, but in the results of factor elasticity, they have a somewhat different impact. Second, while the support of CEOs is relatively more elastic than other consulting factors with respect to the completion of consulting projects, the institutional condition for consulting is relatively more elastic than other factors with respect to the contribution to business performance. Third, since the high-firm age group has a greater capacity to absorb and utilize external knowledge and resource, the consultant competency and institutional conditions have a more impact on the consulting performance than the low-firm age group. On the other hand, in the low-firm age group, the result indicates that the support of CEOs has a more impact in the consulting performance than the high-firm age group. According to the total effect, the support of CEOs in the entire model has the highest impact on the consulting performance. Thus, it is probably difficult to achieve the improvement of business performance through consulting as well as the successful consulting projects without the CEOs' commitment and awareness about the consulting projects.

• 대한화장품학회지
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• 제33권3호
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• pp.181-187
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• 2007

본 연구에서는 고려엉겅퀴 추출물의 항산화 효과, 사람섬유아세포에 자외선에 의해 유도된 MMP-1 발현에 대한 영향 및 피부탄력 개선효과에 대하여 연구하였다. 고려엉겅퀴 추출물의 DPPH radical과 superoxide anion radical 소거효과는 처리 농도가 증가함에 따라 농도 의존적으로 소거효과를 나타냈으며, 각각 1 mg/mL에서 87.47 %와 61.71 %로 DPPH radical과 superoxide anion radical을 소거하여 우수한 항산화 효과를 나타내었다. 고려엉겅퀴 추출물의 지질과산화 억제효과는 100 ${\mu}g/mL$ 농도에서 95.54%의 지질과산화 저해효과를 나타내었다. 또한, 자외선 조사에 의해 사람 섬유아세포에서 증가되는 MMP-1의 단백질 발현은 고려엉겅퀴 추출물을 100 ${\mu}g/mL$ 농도로 처리하였을 때 54.69% 감소하였다. 피부의 탄력 개선 효과를 알아보기 위해 고려엉겅퀴 추출물을 500 ${\mu}g/mL$ 함유한 O/W 에멀젼을 이용한 임상실험에서 피부의 탄력 개선 효과를 확인하였다. 본 연구를 통하여 고려엉겅퀴 추출물은 항산화 효과와 자외선으로부터 생성되는 MMP-1의 발현을 저해하고 피부의 탄력을 개선함으로써 항노화 소재로서의 응용가능성을 확인하였다.

• 한국산학기술학회논문지
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• 제15권4호
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• pp.2303-2309
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• 2014

본 연구는 자동미세다륜침 적용한 한 뒤 EGF를 50대여성의 노화피부에 공급하여 수분과 탄력의 증가, 색소와 눈가주름의 감소에 효과를 알아보는데 목적이 있다. 본 연구는 50대여성 35명을 대상으로 2013년 10월 7일부터 2013년 12월 15일까지 총 70일간 이루어졌다. 연구결과 자동미세다륜침의 사용만으로 수분(<.01), 탄력(<.001)이 좋아졌으며, 색소(<.01)와 주름(<.001)이 감소하였다. 또한 활성성분인 EGF를 적용하였을 때 자동미세다륜침만 사용하였을 때 보다 좋은 결과를 나타냈다. 이에 재생을 촉진하는 EGF 등의 활성성분을 함께 사용한다면 긍정적인 효과를 더욱 증대시킬 것으로 사료된다.

• 대한본초학회지
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• 제22권4호
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• pp.227-232
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• 2007

Objectives : We investigated the physiological effects of the cosmetic products with Saccharomyces fermented modified Kyungohkgo extract (SFKE) for 6 weeks on human skin by using non-invasive instruments. Methods : We measured physiological effects such as a skin moisturizing effect, an elasticity and an evenness on the skin of older than 40 years volunteers(female, n=25) who were applied with the cosmetic products containing SFKE for 6 weeks. Results : We observed the physiological effect after using the cosmetic products for 6 weeks. After using the cosmetic product, the skin moisture contents were increased in human skin. The skin elasticity were not only increased in face skin through using the product, but also evenness of skin were improved. Conclusions : We concluded that the cosmetic products containing the SFKE had and physiological effects on the human face skin.

• International Journal of Concrete Structures and Materials
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• 제7권3호
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• pp.183-191
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• 2013

Prestress losses assumed for bridge girder design and deflection analyses are dependent on the concrete modulus of elasticity (MOE). Most design specifications, such as the American Association of State Highways and Transportation Officials (AASHTO) bridge specifications, contain a constant value for the MOE based on the unit weight of concrete and the concrete compressive strength at 28 days. It has been shown in the past that that the concrete MOE varies with the age of concrete. The purpose of this study was to evaluate the effect of a time-dependent and variable MOE on the prestress losses assumed for bridge girder design. For this purpose, three different variable MOE models from the literature were investigated: Dischinger (Der Bauingenieur 47/48(20):563-572, 1939a; Der Bauingenieur 5/6(20):53-63, 1939b; Der Bauingenieur, 21/22(20):286-437, 1939c), American Concrete Institute (ACI) 209 (Tech. Rep. ACI 209R-92, 1992) and CEB-FIP (CEB-FIP Model Code, 2010). A typical bridge layout for the Dallas, Texas, USA, area was assumed herein. A prestressed concrete beam design and analysis program from the Texas Department of Transportation (TxDOT) was utilized to determine the prestress losses. The values of the time dependent MOE and also specific prestress losses from each model were compared. The MOE predictions based on the ACI and the CEB-FIP models were close to each other; in long-term, they approach the constant AASHTO value. Dischinger's model provides for higher MOE values. The elastic shortening and the long term losses from the variable MOE models are lower than that using a constant MOE up to deck casting time. In long term, the variable MOE-based losses approach that from the constant MOE predictions. The Dischinger model would result in more conservative girder design while the ACI and the CEB-FIP models would result in designs more consistent with the AASHTO approach.

• Archives of Plastic Surgery
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• 제42권3호
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• pp.282-287
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• 2015

Background Morphological changes that accompany aging, such as wrinkles and skin laxity, are particularly prominent on facial skin. Recently, facial rejuvenation using the hydrofilling effect of hyaluronic acid (HA) filler has been employed for improvement of skin texture. In this study, we studied rejuvenating effects of stabilized HA (Restylane Vital) through direct intradermal injections. Methods A total of 30 female patients underwent a series of procedures on face, including three sessions at intervals of four weeks. A total of 2 mL of Restylane Vital was injected along the whole face using an automatic injector. Improvement of skin surface roughness, elasticity, brightness, moisture, and fine wrinkles was evaluated. Patient satisfaction was evaluated, and pictures of patients were taken at each visit and 6 months after last treatment session. Scoring for each patient was performed by three doctors according in five subjects. Moisture, oil and elasticity were measured before the procedure and before the last treatment in 10 patients. Results The majority of patients (77%) were satisfied with the therapeutic outcomes. Approximately 66% of patients responded that the effects of this procedure persisted for longer than four months, and the majority of patients (77%) wanted to undergo this procedure again and would recommend this procedure to acquaintances. Regarding doctors' evaluation, scores for improvement of skin surface roughness, elasticity, and brightness were significantly higher than those for improvement of moisture and fine wrinkle. Conclusions Intradermal injection of HA can have a rejuvenating effect on dry and tired facial skin, especially in improvement of skin surface roughness.

• 국제지역연구
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• 제15권2호
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• pp.51-76
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• 2011

본 연구에서는 1975년부터 2006년 사이 일본의 12개 권역별 자료를 이용하여 일본의 공공투자정책의 유효성이 1990년대에 비해 2000년대에 얼마나 개선되었는가에 대해 검토하였다. 실증분석의 결과는 첫째, 2000년대 공공자본에 대한 생산탄력성에 있어서 1990년대보다 상승하였다는 증거는 없으며 오히려 차분 GMM 추정방식 등에서는 하락한 것으로 나타났다. 둘째, 공공자본은 민간자본의 한계생산성을 대체로 증가시키는 것으로 나타났지만, 향상정도에 있어서는 1990년대에 비해 2000년대에 더 개선되었다고 말하기 어려운 것으로 나타났다. 셋째, 공공투자 수행과정에서 민간투자 구축여부에 관한 분석결과에서는 전 기간에 걸쳐 공공투자 수행 시 민간투자를 구축시키는 것으로 나타나 신고전학파의 주장을 지지하였다. 그리고 2000년대에는 민간투자 구축정도가 더 심화되는 것으로 나타났다. 이상의 실증분석 결과를 통해 2000년대의 개혁 조치들이 민간투자의 활성화 및 민간경제부문 성과로는 제대로 이어지지 못한 것으로 판단한다.

• Advances in concrete construction
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• 제7권3호
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• pp.151-166
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• 2019

This paper introduces a new efficient analytical method, based on shear deformations obtained with 2D elasticity theory approach, to perform an explicit closed-form solution for calculation the interfacial shear and normal stresses in plated RC beam. The materials of plate, necessary for the reinforcement of the beam, are in general made with fiber reinforced polymers (Carbon or Glass) or steel. The experimental tests showed that at the ends of the plate, high shear and normal stresses are developed, consequently a debonding phenomenon at this position produce a sudden failure of the soffit plate. The interfacial stresses play a significant role in understanding this premature debonding failure of such repaired structures. In order to efficiently model the calculation of the interfacial stresses we have integrated the effect of shear deformations using the equilibrium equations of the elasticity. The approach of this method includes stress-strain and strain-displacement relationships for the adhesive and adherends. The use of the stresses continuity conditions at interfaces between the adhesive and adherents, results pair of second-order and fourth-order coupled ordinary differential equations. The analytical solution for this coupled differential equations give new explicit closed-form solution including shear deformations effects. This new solution is indented for applications of all plated beam. Finally, numerical results obtained with this method are in agreement of the existing solutions and the experimental results.

• Advances in nano research
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• 제14권4호
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• pp.375-389
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• 2023

In this study, free vibration analysis of functionally graded (FG) porous truncated conical shell panels reinforced by graphene platelets (GPLs) has been investigated for the first time. Additionally, the effect of three different types of porosity distribution and five different types of GPLs patterns on dynamic response of the shell are also studied. Halpin-Tsai micromechanical model and Voigt's rule are used to determine Young modulus, shear modulus and Poisson's ratio with mass densities of the shell, respectively. The main novelties of present study are: applying 3D elasticity theory and the finite element method in conjunction with Rayleigh-Ritz method to give more accurate results unlike other simplified shell theories, and also presenting a general 3D solution in cylindrical coordinate system that can be used for analyses of different structures such as circular, annular and annular sector plates, cylindrical shells and panels, and conical shells and panels. A convergence study is performed to justify the correctness of the obtained solution and numerical results. The impact of porosity and GPLs patterns, the volume of voids, the weight fraction of graphene nanofillers, semi vertex and span angles of the cone, and various boundary conditions on natural frequencies of the functionally graded panel have been comprehensively studied and discussed. The results show that the most important parameter on dynamic response of FG porous truncated conical panel is the weight fraction of nanofiller and adding 1% weight fraction of nanofiller could increase 57% approximately the amounts of natural frequencies of the shell. Moreover, the porosity distribution has great effect on the value of natural frequency of structure rather than the porosity coefficient.