• Structural Engineering and Mechanics
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• 제15권2호
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• pp.249-267
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• 2003

In this study, circular plates subjected to general type of loads and supported on a two-parameter elastic foundation are analysed. The stiffness, elastic bedding and soil shear effect matrices of a fully compatible ring sector plate element, developed by Saygun (1974), are obtained numerically assuming variable thickness of the element. Ring sector soil finite element is also defined to determine the deflection of the soil surface outside the domain of the plate in order to establish the interaction between the plate and the soil. According to Vallabhan and Das (1991) the elastic bedding (C) and shear parameters ($C_T$) of the foundation are expressed depending on the elastic constants ($E_s$, $V_s$) and the thickness of compressible soil layer ($H_s$) and they are calculated with a suitable iterative procedure. Using ring sector elements presented in this paper, permits the generalization of the loading and the boundary conditions of the soil outside the plate.

• 한국응용과학기술학회지
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• 제26권3호
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• pp.240-247
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• 2009

The purpose of this study is to develop a method to evaluate solubility parameter interactions of cosmetic ingredients in formulations. This experimentation relates to the fabrication of new multi-layer cleansing oil which can remove make-up products such as lipstick, foundation, mascara, eye shadow, etc., and also can wash away dirt and sebum from the skin just in one stage process. Solubility parameter and specific gravity of various cosmetic ingredients are measured to explain the cleanliness of interface, detergency of make-up cosmetics on the skin surface. The results suggest that it is possible for cosmetic chemists to use solubility parameter of cosmetic materials for fabrication of new formulation of 3-layer cleansing oil.

• Steel and Composite Structures
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• 재36권6호
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• pp.711-727
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• 2020

In the present research, the free vibration analysis of functionally graded (FG) nanocomposite deep spherical shells reinforced by graphene platelets (GPLs) on elastic foundation is performed. The elastic foundation is assumed to be Winkler-Past ernak-type. It is also assumed that graphaene platelets are randomly oriented and uniformly dispersed in each layer of the nanocomposite shell. Volume fraction of the graphene platelets as nanofillers may be different in the layers. The modified HalpinTsai model is used to approximate the effective mechanical properties of the multilayer nanocomposite. With the aid of the first order shear deformation shell theory and implementing Hamilton's principle, motion equations are derived. Afterwards, the generalized differential quadrature method (GDQM) is utilized to study the free vibration characteristics of FG-GPLRC spherical shell. To assess the validity and accuracy of the presented method, the results are compared with the available researches. Finally, the natural frequencies and corresponding mode shapes are provided for different boundary conditions, GPLs volume fraction, types of functionally graded, elastic foundation coefficients, opening angles of shell, and thickness-to-radius ratio.

• 한국표면공학회지
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• 제50권3호
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• pp.183-191
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• 2017

In this study, surface morphology and mechanical property of TiN and DLC coated pedicle screw have been investigated by field-emission scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, vickers hardness test, axial gripping, and axial torsional gripping capacity test. From the EDS and XRD results, the composition and crystal structure of TiN and DLC coated surface were verified. The hardness value was increased by TIN and DLC coating, and the DLC coating surface has the highest value. The gripping capacity also showed higher value for TiN and DLC coated specimen than that of non-coated (Ti alloy) surface. The surface morphology of gripping tested specimen showed rougher scratched surface from Ti alloy than TiN and DLC coated layer.

• Advances in nano research
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• 제6권3호
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• pp.279-298
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• 2018

Present investigation deals with the free vibration characteristics of nanoscale-beams resting on elastic Pasternak's foundation based on nonlocal strain-gradient theory and a higher order hyperbolic beam model which captures shear deformation effect without using any shear correction factor. The nanobeam is lying on two-parameters elastic foundation consist of lower spring layers as well as a shear layer. Nonlocal strain gradient theory takes into account two scale parameters for modeling the small size effects of nanostructures more accurately. Hamilton's principal is utilized to derive the governing equations of embedded strain gradient nanobeam and, after that, analytical solutions are provided for simply supported conditions to solve the governing equations. The obtained results are compared with those predicted by the previous articles available in literature. Finally, the impacts of nonlocal parameter, length scale parameter, slenderness ratio, elastic medium, on vibration frequencies of nanosize beams are all evaluated.

• 한국농촌건축학회논문집
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• 제23권3호
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• pp.1-8
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• 2021

Rural multi-purpose buildings needs to ensure their safety against various disasters. Therefore, a pile foundation, which is a foundation type that can transmit the load of the structure to the bedrock layer, has been designed. The pile foundation method is largely divided into driving piles method and pre-bored pile method. Recently, in order to respond to the Noise and Vibration Control Act and related environmental complaints, construction of pile foundation adopts pre-bored pile method. The bearing capacity of the pre-bored pile method is calculated through a load test in situ. However, a disadvantage stems in that it is difficult to measure the ultimate bearing capacity due to field conditions. Therefore, in this study, the skin frictional force of pre-bored pile was measured through a model test in laboratory for each pile filling material. In result, the pile filling material with using circulating resources shows superior skin frictional force than ordinary portland cement. This study also judged that the result can be applied in place of ordinary Portland cement in the field.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2008년도 추계 학술논문 발표대회
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• pp.37-41
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• 2008

According to the recent rapidly increasing that construction works are gradually Manhattanized mainly the grand scaled residential buildings, the foundation of the building that is related to safety is increasing for building as a grand scaled mat concrete. Because mat concrete can not be simultaneously placing of concrete in a great quantity due to the circumstance at the field, the inequal deformation of the tensile stress that according to the time lag of hydration heat between the upper layer and the lower layer is affecting as a cause that is the possibility of crack occurrence by increasing. Accordingly, this research checked the efficiency of super retard concrete in applying real structures, and we implemented the preparatory experiment to settle up the inequal deformation of the tensile stress substantially that is according to the time lag of placement between the upper layer and the lower layer by controlling the setting time using the super retarding agent. As the result of test, the more target of delay time lengthened, the more fluidity increased and air content indicated a little differences. There was from 2 to 10 hours between the standard curing and the outside curing at the setting time and in case of calculating the rate of mixing at real structure is required that mix promotion, increasing the amount of mixing, by setting up the curing temperature. The super retard concrete showed the result that in compressive strength, early-age strength was smaller than normal concrete whereas it was same or more figures from at the aging 28days because of the super retarding agent.

• Geomechanics and Engineering
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• 제37권5호
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• pp.511-525
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• 2024

Micropiled raft has been used to support the existing and new structures or to provide the seismic reinforcement of foundation systems. Recently, research on micropile or micropiled raft has been actively conducted as the usage of micropile has increased, and the reinforcement effect of pile for the raft, the pile installation methods, and methods for calculating the bearing capacity of micropiled raft have been proposed. In addition, existing research results show that the behavior of this foundation system is different depending on the pile conditions and can be greatly influenced by the characteristics of the upper or lower ground depending on the conditions of pile. In other words, considering that the micropile is a friction pile, it can be predicted that the reinforcing effect of micropile for the raft and the bearing capacity of micropiled raft may depend on the cohesion of upper soil layer depending on the pile conditions. However, existing studies have limitations in that they were conducted without taking this into account. However, existing studies have limitations as they have been conducted without considering these characteristics. Accordingly, this study investigated the reinforcing effect of micropile and the bearing characteristics of micropiled raft by varying the cohesion of upper soil layer and the stiffness of pile which affect the behavior of micropiled raft. In this results, the reinforcing effect of micropile on the raft also increased as the cohesion of soil layer increased, but the reinforcing effect of pile was more effective in ground conditions with decreased the cohesion. In addition, the relationship between the axial stiffness of micropile and the bearing capacity of micropiled raft was found to be a logarithmic linear relationship. It was found that the reinforcing effect of micropile can increase the bearing capacity of raft by 1.33~ 3.72 times depending on the cohesion of soil layer and the rigidity of pile.

• Journal of Acupuncture Research
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• 제32권2호
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• pp.1-9
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• 2015

Objectives : The present study was an evaluation and standardization of herbal components in order to establish the efficacy and safety of Shinbaro pharmacopuncture. Methods : Among the raw materials of Shinbaro pharmacopuncture, the components Cibotii Rhizoma, Eucommiae Cortex, and Ledebouriellae Radix were assessed through ingredient verification experiments using thin-layer chromatography(TLC) and ultraviolet rays(UV) lamps. In addition, we standardized Acanthopanacis Cortex and Achyranthis Radix through validation using high performance liquid chromatograph-diode array detector(HPLC-DAD). Results : As result appeared a blue-white fluorescence under ultraviolet rays; changed to dark green after adding 1 % ferric chloride solution(due to Cibotii Rhizoma), and presented a yellow-green fluorescence when mixed with an ethyl ether under UV lamps by way of the ethyl ether layer, confirming Eucommiae Cortex. Ledebouriellae Radix was confirmed as dark brown spots at Rf values of 0.56 and 0.71 using TLC. Additionally, Acanthopanacis Cortex and Achyranthis Radix HPLC test results showed that linearity was $R^2{\geq}0.99$, and detection limit and quantitation limit were 0.23 to $1.29{\mu}g/mL$, and 0.71 to $3.90{\mu}g/mL$, respectively. Furthermore, precision and accuracy were confirmed to have relative standard deviation(RSD) values of 0.10 to 1.89 % and 96.19 to 103.72 %, respectively. Shinbaro pharmacopuncture did not have any overlapping or interference from other peaks in detection under the abovementioned analysis conditions. Conclusions : In conclusion, we confirmed that maintenance of Shinbaro pharmacopuncture validity was possible by means of quality control of Cibotii Rhizoma, Eucommiae Cortex, and Ledebouriellae Radix through ingredient identification and Acanthopanacis Cortex and Achyranthis Radix through high performance liquid chromatograph(HPLC) analysis. Further, we hope to contribute to the development strategy of herbal industry acupuncture.

• Geomechanics and Engineering
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• 제4권4호
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• pp.263-279
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• 2012

The present paper deals with the analysis of combined footings resting on geosynthetic reinforced granular fill overlying stone column improved poor soil. An attempt has been made to study the influence of inclusion of geosynthetic layer on the deflection of the footing. The footing has been idealized as a beam having finite flexural rigidity. Granular fill layer has been represented by Pasternak shear layer and stone columns and poor soil have been represented by nonlinear Winkler springs. Nonlinear behavior of granular fill layer, stone columns and the poor soil has been considered by means of hyperbolic stress strain relationships. Governing differential equations for the soil-foundation system have been derived and solution has been obtained employing finite difference scheme by means of iterative Gauss Elimination method. Results of a detailed parametric study have been presented, for a footing supporting typically five columns, in non-dimensional form in respect of deflection with and without geosynthetic inclusion. Geosynthetic layer has been found to significantly reduce the deflection of the footing which has been quantified by means of parametric study.