• 대한정형도수물리치료학회지
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• 제25권2호
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• pp.39-46
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• 2019

Background: Ground repulsion or impact on the ground during daily activities, sports, or occupational activities may cause injury to the knee when walking. Non-elastic taping is effective in treating these problems in previous studies. Non-elastic taping strengthens the structure of the soft tissues of the injured knee joint to maintain constant tension, improves muscle rearrangement and function, and improves proprioception. Based on previous studies, we intended to see the therapeutic changes of non-elastic taping in patients with patellofemoral joint pain syndrome. Methods: The non-elastic taping application method was applied to the patient three times for five hours for one week. Non-elastic taping was applied to the patellar tendon with little space above the skin segment of the patellar femur, with both sides fixed by taping. Muscle strength and gait change were evaluated with non-elastc taping. Results: The knee flexion, extension strength and gait evaluation of the knee joint with inelastic taping showed significant differences after treatment. There was a significant difference in the comparison between the two groups after the treatment method was applied (p<.05). Conclusion: As a result, this study confirms that the non-elastic taping method applied for the treatment of patellar femoral joint pain syndrome is effective in the treatment.

• Ocean and Polar Research
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• 제27권1호
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• pp.35-44
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• 2005

The bathymetric and gravity data were obtained in 2001 and 2003 during a survey of seamounts in the northwest of the Marshall Islands, western Pacific. The study areas are located in the Pigafetta Basin which is the oldest part of the Pacific plate and in the Ogasawara Fracture Zone which formed from the spreading ridge between the Izanagi and Pacific plates in the Jurassic. The densities of seamounts and the elastic thickness values of the lithosphere are calculated by using three-dimensional flexure modeling considering the constant sediment layer in the infinite plate model. Very low elastic thickness values (5km), relatively young seamounts, and old lithosphere in the east study area suggest the possibility of the rejuvenation of lithosphere by widespread volcanisms, whereas the elastic thickness values (15km), relatively old seamounts, and young lithosphere of the west study area are suitable for a simple cooling plate model of $300-600^{\circ}C$ isotherm. The gravity residuals of OSM6-1 and OSM6-2 suggest the possibility of different load density or elastic thickness. Relatively older OSM6-2 formed on the younger lithosphere with relatively thin elastic thickness, while younger OSM6-1 on the older lithosphere with relatively thick elastic thickness.

• 비파괴검사학회지
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• 제22권2호
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• pp.140-148
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• 2002

중수로 압력관으로 사용되는 Zr-2.5Nb 재료의 고온 이방성 탄성계수를 고온 초음파공명분광법(RUS)로 측정하였다. 소형 가열로 내에 알루미나 waveguide와 광대역 초음파 센서를 사용하여 초음파에너지를 시편에 가하고 시편의 공명주파수를 측정하였다. 압력관의 축 방향, 반경 방향, 원주 방향에 일치하도록 장방형 시편을 가공하였으며 각 방향에 대한 탄성계수 텐서 9개의 값을 상온${\sim}500^{\circ}C$ 온도 구간에서 측정하였다. 탄생계수 텐서, $c_{ij}$는 모두 온도가 증가함에 따라 점진적으로 감소하며 원주 방향의 탄성계수가 축 방향 및 반경 방향의 탄성계수보다 높았다. 이것은 Young's modulus나 shear modulus의 경우에도 일치하였으며 축 방향과 반경 방향의 경우 큰 차이를 나타내지 않았다. 축 방향 및 반경 방향의 비틀림 탄생계수가 $150^{\circ}C$ 부근에서 서로 교차하였으며 이는 단결정 지르코늄의 $c_{44}$ 및 $c_{66}$의 교차 현상과 일치하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2007년도 추계학술대회 논문집
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• pp.429-430
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• 2007

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2000년도 International Symposium on Magnetics The 2000 Fall Conference
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• pp.457-458
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• 2000

• Earthquakes and Structures
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• 제10권5호
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• pp.1033-1048
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• 2016

An analytical solution based on the neutral surface concept is developed to study the free vibration behavior of simply supported functionally graded plate reposed on the elastic foundation by taking into account the effect of transverse shear deformations. No transversal shear correction factors are needed because a correct representation of the transversal shearing strain obtained by using a new refined shear deformation theory. The foundation is described by the Winkler-Pasternak model. The Young's modulus of the plate is assumed to vary continuously through the thickness according to a power law formulation, and the Poisson ratio is held constant. The equation of motion for FG rectangular plates resting on elastic foundation is obtained through Hamilton's principle. Numerical examples are provided to show the effect of foundation stiffness parameters presented for thick to thin plates and for various values of the gradient index, aspect and side to thickness ratio. It was found that the proposed theory predicts the fundamental frequencies very well with the ones available in literature.

• 한국생산제조학회지
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• 제24권5호
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• pp.475-480
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• 2015

Ultrasonic atomic force microscopy (Ultrasonic-AFM) has been used to investigate the elastic property of the ultra-thin coating layer in a thin-film system. The modified Hertzian theory was applied to predict the contact resonance frequency through accurate theoretical analysis of the dynamic characteristics of the cantilever. We coat 200 nm thick Aluminum and Titanium thin films on the substrate using the DC Magnetron sputtering method. The amplitude and phase of the contact resonance frequency of a vibrating cantilever varies in response to the local stiffness constant. Ultrasonic-AFM images were obtained using the variations in the elastic property of the materials. The morphology of the surface was clearly observed in the Ultrasonic-AFM images, but was barely visible in the topography. This research demonstrates that Ultrasonic-AFM is a promising technique for visualizing the distribution of local stiffness in the nano-scale thin coatings.

• Computers and Concrete
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• 제25권3호
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• pp.215-224
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• 2020

In the present study, according to the important of porosity in low specific weight in comparison of high stiffness of carbon nanotubes reinforced composite, buckling and free vibration analysis of sandwich composite beam in two configurations, of laminates using differential quadrature method (DQM) is studied. Also, the effects of porosity coefficient and three types of porosity distribution on critical buckling load and natural frequency are discussed. It is shown the buckling loads and natural frequencies of laminate 1 are significantly larger than the results of laminate 2. When configuration 2 (the core is made of FRC) and laminate 1 ([0/90/0/45/90]_s) are used, the first natural frequency rises noticeably. It is also demonstrated that the influence of the core height in the case of lower carbon volume fractions is negligible. Even though, when volume fraction of fiber increases, the critical buckling load enhances smoothly. It should be noticed the amount of decline has inverse relationship with the beam aspect ratio. Investigating three porosity patterns, beam with the distribution of porosity Type 2 has the maximum critical buckling load and first natural frequency. Among three elastic foundations (constant, linear and parabolic), buckling load and natural frequency in linear variation has the least amount. For all kind of elastic foundations, when the porosity coefficient increases, critical buckling load and natural frequency decline significantly.

• 한국기계가공학회지
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• 제19권3호
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• pp.77-85
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• 2020

In this study, we proposed a method to replace the solid finite element model of the boiler membrane wall for coal-fired power plants using an equivalent shell model. The application of a bending load to the membrane wall creates greater displacement at both ends of the central portion when compared with the middle when an isotropic elastic constant is used in the shell model. This is inconsistent with the results of the solid model where the central portion is uniformly deformed. Here, we presented a method to determine the orthotropic elastic constants of the shell model in terms of bending stiffness and vibration characteristics to solve this problem. Our analysis of the orthotropic shell model showed that the error ratio was 0.9% for the maximum displacement due to the bending load, 0.3% for the first natural frequency, and 2.5% for the second natural frequency when compared with the solid model. In conclusion, a complicated boiler membrane wall composed of a large number of pipes and fins can be replaced with a simple shell model that shows equivalent bending stiffness and vibration characteristics using our proposed method.

• 대한기계학회논문집
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• 제10권5호
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• pp.787-797
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• 1986

본 논문에서는 축대칭 선형 문제의 경계적분법에 대한 일반화한 정식화 과정 및 수치적 접근방법이 제시되었으며 정식화 과정 중 Navier 방정식의 기본해로부터 도 출되는 변위 및 표면적 Kernel을 구하는 Hankel 변환법을 이용한 $\ulcorner$직접축대칭접근법 $\lrcorner$과 3차원 Kevin 해로부터 원주경로 따라 적분한 $\ulcorner$3차원 접근법$\lrcorner$이 비교 검토되었 다.