• Geomechanics and Engineering
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• v.32 no.4
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• pp.397-409
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• 2023

This study examines two traditional approaches (non-linear elastic and elasto-plastic) in association with 2D and 3D FEM analyses of a box-section pile embedded in sand. A particular emphasis is placed on stress singularities concerning both reentrant corners of the pile section and the resulting tension zones. From the experience gained in this study, non-linear elastic soil models are less restrictive when one considers stress singularities and their possible effects on convergence of the solution. At least for monotonic loading, when compared with field tests, non-linear elastic models yield better results than the plasticity ones. On the other hand, although elasto-plastic models are not limited to monotonic loading, they are much more sensitive to stress singularities. For this reason, a spherical elastic region is necessary at the pile tip to ensure convergence. Without this region, one must artificially impose an apparent cohesion to limit the tension stresses within a sand medium.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.9
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• pp.1023-1029
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• 2010

In this paper, we proposed the broadband polarization diversity antenna operating in the PCS, WCDMA and WiBro band for mobile base station. We designed the antenna using the dipole antenna of the square loop type and microstrip feeding structure. Additionally, we used the choke box to remove the distortion of radiation patterns by the reflector structure when operating broadband. The simulation was performed using MWS in a commercial tool of CST company and the antenna was fabricated on a teflon substrate with 3.33 of the relative permittivity. The proposed antenna has the bandwidth of 640 MHz(from 1.75 to 2.39 GHz) when VSWR is below 1.5. At the operating bands, the interisolation between the cross-pair radiators is less than -25 dB and the maximum gains for PCS, WCDMA and WiBro band are 8.9, 8.2 and 8.6 dBi, respectively.

• Food Science of Animal Resources
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• v.41 no.4
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• pp.623-635
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• 2021

The effect of deer antler extract on muscle differentiation and muscle atrophy were evaluated to minimize muscle loss following aging. Various deer antler extracts (HWE, hot water extract of deer antler; FE, HWE of fermented deer antler; ET, enzyme-assisted extract of deer antler; UE, extract prepared by ultrasonication of deer antler) were evaluated for their effect on muscle differentiation and inhibition of 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR)-induced muscle atrophy in C2C12 cells. Morphological changes according to the effect of antler extracts on muscle differentiation were confirmed by Jenner-Giemsa staining. In addition, the expression levels of genes related to muscle differentiation and atrophy were confirmed through qRT-PCR. In the presence of antler extracts, the length and thickness of myotubes and myogenin differentiation 1 (MyoD1) and myogenic factor 5 (Myf5) gene expression were increased compared to those in the control group (CON). Gene expression of AMP-activated protein kinase (AMPK), MyoD1, and myogenin, along with the muscle atrophy factors muscle RING finger-1 (MuRF-1) and forkhead box O3a (FoxO3a) upon addition of deer antler extracts to muscle-atrophied C2C12 cells was determined by qRT-PCR after treatment with AICAR. The expression of MuRF-1 and FoxO3a decreased in the groups treated with antler extracts compared to that in the group treated with AICAR alone. In addition, gene expression of MyoD1 and myogenin in the muscle atrophy cell model was significantly increased compared that into the CON. Therefore, our findings indicate that antler extract can increase the expression of MyoD1, Myf5 and myogenin, inhibit muscle atrophy, and promote muscle differentiation.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.1
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• pp.163-181
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• 1998

In this study, the objective is determine the optimal design variable of engine mount system using the rubber mount of bush-type which is usually utilized in passive control to minimize vibrations of vehicle body or transmission from engine into body. The engine model adopted in this study is 4-cylinder, 4-stroke gasoline engine support- ed by 4-points. The system is modelled in 10 d.o.f.-rigid body motion of the engine & transmission in 6 d.o.f., elastic motion of vehicle body in 4 d.o.f.(1st torsional, 1st vertical and 1st & 2nd lateral bending vibration mode). To consider the elastic motion of vehicle body, find the eigenvalues and mode shapes of vehicle body by nodal testing and then determine the modal masses and stiffnesses of the body. The design variables of the engine mount system are locations, stiffness and damping coefficients of the rubber mounts(28 design variables). In case of considering the torque-roll axis for the engine, the design variables of the mount system are reduced to 22 design variables. The objective functions in optimal design process are considered by three cases, that is, 1) transmitted forces through engine mounts, 2) acceleration components of generalized coordinates for the vibration of vehicle body, 3) acceleration of specified location(where gear box) of body. three case are analyzed and compared with each other.

• KEPCO Journal on Electric Power and Energy
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• v.1 no.1
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• pp.181-188
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• 2015

The non-contact permanent magnet gear has advantages of high efficiency and improved reliability. It has other advantages of no mechanical friction loss, very little noise and vibration, and no need for lubricant. With these advantages, the non-contact permanent magnet gear that solves the physical contact problem of the mechanical gear has drawn attention. Due to this unique non-contact characteristic, the non-contact permanent magnet gear which is capable of non-contact torque transmission has replaced mechanical gear. The mechanical gears which is in many fields of the modern industry, is used mostly for power transmitting mechanical devices. However, it also has the problem of a low torque density, which requires improvement. In this paper, a novel pole piece shape is proposed in order to improve the problem of low torque density of the non-contact permanent magnet gear. The experiment data required for predicting the relationships among them are obtained using finiteelement Operating method based on two-dimensional (2-D) numerical analysis. Therefore, this paper derived an optimal model for thenon-contact permanent magnet gear with the novel pole piece using the Box-Behnken design, and the validity of the optimal design of the proposed pole piece shape through variance analysis and regression analysis demonstrated. In this paper, we performed the thransfer torque analysis in order to improve the torque density and power density, we have performed on optimal design of proposed pole piece shape using box-behnken.

• Fashion & Textile Research Journal
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• v.22 no.1
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• pp.11-24
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• 2020

This research examines pattern production of 3 men's costumes in the second half of 19th century by 3D reconstruction to reveal technical aspects of mail costumes. The steps are as follows. First, an examination of selective type according to research study. Second, a pattern analysis of 3 historical male tops of 19th century referred to 9 pattern books of the France National Library collection. Third, a categorized type analysis that referred to paintings of the Musée d'Orsay collection. Fourth, a measurement and structure research of 3 historical garments of Fashion and Textile Museum collection. Fifth, the pattern making and fitting by 3D simulation. Research discussed the following subjects and results. First, main type of men's coat can be categorized by frac, redingote, jaquette, and veston. Second, the male costume pattern contained in pattern books was researched along with distinguished silhouettes and structures; X silhouette for frac and redingote, H silhouette for jaquette, and straight box silhouette for veston. Third, based on the analysis of representative type of men's costume per period conducted previous studies, 2 redingotes and a jaquette in the museum were selected and compared to other data such as image materials. Last, the following process was conducted for reconstruction; 'Drawing diagram-Primary pattern drafting by measurement value-3D virtual fitting-Checking the fit-Modification and complement'. We also obtained a 3D virtual reconstruction and a 2D research pattern that suggested a costume pattern by each type along with 3D reconstruction that included insights for male coat techniques of 19th century France.

• 한국연소학회:학술대회논문집
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• 2000.12a
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• pp.168-174
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• 2000

A diode laser sensor system based on absorption spectroscopy techniques has been developed to measure $CO_2$ concentration and temperature non-intrusively in high temperature combustion environments using a 2.0 ${\mu}m$ DFB(Distributed Feedback) laser. Two optics was fabricated in pig-tail fashion and all optical components were implemented in a single box. The evolution of measurement sensitivity was done using test cell by changing sweep frequency and $CO_2$ concentration. Gas temperature was determined from the ratio of integrated line strengths. Species concentration was determined from the integrated line intensity and the measured temperature. The result show that the system has 2% error in wide operation frequency range and accuracy of $CO_2$ concentration was about 3%. The system was applied to measure temperature and concentration in the combustion region of a premixed $CH_4$ +air triangular flame. The measurement results of gas temperature agreed well with thermocouple results. Many considerations were taken into account to reduce optical noise, etalon effect, beam steering and base line matching problem. The evaluations results and actual combustion measurement demonstrate the practical and applicability for in-situ and real time combustion monitoring in a practical system.

• The Journal of the Acoustical Society of Korea
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• v.37 no.5
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• pp.363-368
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• 2018

Recently a slat type ceiling is widely used in various spaces, such as music performance spaces and concourse of airport and a general reception area of a building. However, it is hard to find a proper design guideline or material useful in designing such spaces, due to the lack of relevant researches on the effect of a slat ceiling on room acoustics. The present work investigated the effect of a slat type ceiling using a physical scale model method. A 1/20 scale model of a small shoe-box type music performance hall was built and a slat ceiling with different configurations was installed. 6 cases of different ceiling configurations were considered with the combination of 2 slat ceiling height cases and 3 distance cases between slats. The effect of a slat ceiling on the acoustics of a room was evaluated by measuring reverberance($T_{30}$), intelligibility and clarity($D_{50}$ and $C_{80}$), and loudness(G and $G_{80}$).

• Nuclear Engineering and Technology
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• v.40 no.6
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• pp.467-476
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• 2008

To keep the superconducting (SC) magnet coils of KSTAR at proper operating conditions, not only the coils but also other cold components, such as thermal shields (TS), magnet structures, SC bus-lines (BL), and current leads (CL) must be maintained at their respective cryogenic temperatures. A helium refrigeration system (RRS) with an exergetic equivalent cooling power of 9 kW at 4.5 K without liquid nitrogen ($LN_2$) pre-cooling has been manufactured and installed. The main components of the KST AR helium refrigeration system (HRS) can be classified into the warm compression system (WCS) and the cryogenic devices according to the operating temperature levels. The process helium is compressed from 1 bar to 22 bar passing through the WCS and is supplied to cryogenic devices. The main components of cryogenic devices are consist of cold box (C/B) and distribution box (D/B). The C/B cool-down and make the various cryogenic helium for the KSTAR Tokamak and the various cryogenic helium is distributed by the D/B as per the KSTAR requirement. In this proceeding, we will present the commissioning results of the KSTAR HRS. Circuits which can simulate the thermal loads and pressure drops corresponding to the cooling channels of each cold component of KSTAR have been integrated into the helium distribution system of the HRS. Using those circuits, the performance and the capability of the HRS, to fulfill the mission of establishing the appropriate operating condition for the KSTAR SC magnet coils, have been successfully demonstrated.

• Korean Journal of Computational Design and Engineering
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• v.21 no.3
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• pp.296-305
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• 2016

This paper proposes a framework to automatically align Dental range image captured by depth sensors like the Microsoft Kinect. Aligning dental images by intraoral scanning technology is a difficult problem for applications requiring accurate model of dental-scan datasets with efficiency in computation time. The most important thing in dental scanning system is accuracy of the dental prosthesis. Previous approaches in intraoral scanning uses a Z-buffer ICP algorithm for fast registration, but it is relatively not accurate and it may cause cumulative errors. This paper proposes additional Alignment using the rough result comes after intraoral scanning alignment. It requires that Each Depth Image of the total set shares some overlap with at least one other Depth image. This research implements the automatically additional alignment system that aligns all depth images into Completed model by computing a network of pairwise registrations. The order of the each individual transformation is derived from a global network and AABB box overlap detection methods.