• Advances in concrete construction
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• v.8 no.3
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• pp.173-185
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• 2019

This article presents a comparative study of the effect of steel layouts on the seismic behavior of transition steel-concrete composite connections, both experimental and analytical investigations of concrete filled steel tube-reinforced concrete (CFST-RC) and steel reinforecd concrete-reinforced concrete (SRC-RC) structures were conducted. The steel-concrete composite connections were subjected to combined constant axial load and lateral cyclic displacements. Tests were carried out on four full-scale connections extracted from a real project engineering with different levels of axial force. The effect of steel layouts on the mechanical behavior of the transition connections was evaluated by failure modes, hysteretic behavior, backbone curves, displacement ductility, energy dissipation capacity and stiffness degradation. Test results showed that different steel layouts led to significantly different failure modes. For CFST-RC transition specimens, the circular cracks of the concrete at the RC column base was followed by steel yielding at the bottom of the CFST column. While uncoordinated deformation could be observed between SRC and RC columns in SRC-RC transition specimens, the crushing and peeling damage of unconfined concrete at the SRC column base was more serious. The existences of I-shape steel and steel tube avoided the pinching phenomenon on the hysteresis curve, which was different from the hysteresis curve of the general reinforced concrete column. The hysteresis loops were spindle-shaped, indicating excellent seismic performance for these transition composite connections. The average values of equivalent viscous damping coefficients of the four specimens are 0.123, 0.186 and 0.304 corresponding to the yielding point, peak point and ultimate point, respectively. Those values demonstrate that the transition steel-concrete composite connections have great energy dissipating capacity. Based on the experimental research, a high-fidelity ABAQUS model was established to further study the influence of concrete strength, steel grade and longitudinal reinforcement ratio on the mechanical behavior of transition composite connections.

• Journal of architectural history
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• v.19 no.1
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• pp.91-104
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• 2010

Korea's stone buildings are varied in their types such as stone pagodas, stone lanterns, stone bridges, stoneworks, etc. These account for more than 30% over the entire cultural properties, but research achievements are lacking compared to wooden buildings. Accordingly, this study aims to identify the shape, role and transition of Tapgu, which had been used to set up boundary at a stone pagoda, one of the stone buildings. The 20th stone pagodas, which have relative accuracy in its forming year, have been studied around national treasure or treasure between 7th century and 9th century. There are a lot of different opinions about the role and meaning of Tapgu, and at this writer's option, Tapgu is defined as follows: First, each structure plays a different role. A structure to pass the load in the upper part to the ground can be seen as a stair or a pedestal, but a structure to form double foundations can be considered as Tapgu. Second, Tapgu can be used to divide areas with stones or stepping stones. As a result, the shape, role and transition of Tapgu is as follows: Firstly, when it comes to its shape, Tapgu includes flagstone type, belt type, double foundation type, compound type. Flagstone type had been used to set up boundary at stone pagodas by using foundation stone, belt type by keeping apart from stone pagodas, and double foundation stone by installing dual foundation stones. Secondly, Tapgu is considered to set up boundary in the case of flagstone and plate stone, and acts like a structure which can prevent surrounding area of stone pagoda from coming up while being stuck around stone pagodas. Belt type was installed only for the purpose of forming boundary. At the bottom, double foundation stone had been used to pass the load in the upper part to the ground in the same way as the foundation stone in the upper part, and the boundaries were set varying the size. Thirdly, when it comes to the transition of Tapgu, flagstone type of boundary stone had been installed in the 7th century, and belt type of boundary stone had been mainly installed in the 8th century. And double foundation stone had been installed in the 9th century. Comprehensively, flagstone type and belt type had been made around the 7th and 8th century when Tapgu was regarded important and stone pagoda started to be built. At the turn to the 9th century, the role of Tapgu had been increasingly losing in the construction of stone pagoda, and foundation stone started to appear.

• Transactions of Materials Processing
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• v.23 no.6
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• pp.369-375
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• 2014

Flexible roll forming allows profiles to have variable cross-sections. However, the profile may have some shape errors, such as, warping which is a major defect. The shape error is induced by geometrical deviations in both the concave zone and the convex zone. In the current study, flexible roll forming was modeled with FE simulations to analyze the shape error and the longitudinal strain distribution along the flange section over the profile. A distribution of analytically calculated longitudinal strains was used to develop relationships between the shape error and the longitudinal strain distribution as a function of the defined shape parameters for the profile. The FE simulations showed that the shape error is primarily affected by the deviations between the distribution of analytically calculated longitudinal strain and the longitudinal strain distribution of the profile. The results show that the shape error can be controlled by designing the shape parameters to control the geometrical deviations at the flange section in the transition zones.

• Fashion & Textile Research Journal
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• v.24 no.6
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• pp.812-824
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• 2022

This study proposes to develop a 3D printed re-entrant(RE) strip by shape memory thermoplastic polyurethane that can be deformed and recovered by thermal stimulation. The most suitable 3D printing infill density condition and temperature condition during shape recovery for mechanical behavior were confirmed. As the poisson's ratio indicated, the higher the recovery temperature, the closer the poisson's ratio to zero and the better the auxetic properties. After recovery testing for five minutes, it appeared that the shape recovery ratio was the highest at 70℃. The temperature range when the shape recovery ratio appeared to be more than 90% was a recovery temperature of more than 50℃ and 60℃ when deformed under a constant load of 100 gf and 300 gf, respectively. This indicated that further deformation occurred after maximum recovery when recovered at a temperature of 80℃, which is above the glass transition temperature range. As for REstrip by infill density, a shape recovery properties of 100% was superior than 50%. Additionally, as the re-entrant structure exhibited a shape recovery ratio of more than 90%, and exhibited auxetic properties. It was confirmed that the infill density condition of 100% and the temperature condition of 70℃ are suitable for REstrips for applying the actuator.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.3
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• pp.305-314
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• 2001

A modified model is proposed for calculation of transitional boundary layer flows. In order to develop the eddy viscosity model for the problem, the flow is divided into three regions; namely, pre-transition region, transition region and fully turbulent region. The pre-transition eddy-viscosity is formulated by extending the mixing length concept. In the transition region, the eddy-viscosity model employs two length scales, i.e., pre-transition length scale and turbulent length scale pertaining to the regions upstream and the downstream, respectively, and a universal model of stream-wise intermittency variation is used as a function bridging the pre-transition region and the fully turbulent region. The proposed model is applied to calculate three benchmark cases of the transitional boundary layer flows with different free-stream turbulent intensity (1%∼6%) under zero-pressure gradient. It was found that the profiles of mean velocity and turbulent intensity, local maximum of velocity fluctuations, their locations as well as the stream-wise variation of integral properties such as skin friction, shape factor and maximum velocity fluctuations are very satisfactorily predicted throughout the flow regions.

• 한국연소학회:학술대회논문집
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• 2004.11a
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• pp.161-166
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• 2004

A study of argon droplet vaporization is conducted using molecular dynamics. Instead of using traditional method such as the Navier-Stokes equation. Molecular dynamics uses Lagrangian frame to describe molecular behavior in a system and uses only momentum and position data of all molecules in the system. So every property is not a hypothetical input but a statistical result calculated from the momentum and position data. This work performed a simulation of the first-order stability for phase transition of a three dementional submicron argon droplet within quiescent environment. Lennard-Jones 12-6 potential function is used as a intermolecular potential function. The molecular configuration is examined while an initially non-sperical droplet is changed into the spherical shape and droplet evaporates or condensates.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.3195-3200
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• 2011

The vibration resulting from railway operation is transmitted through the track and line structure, ground movements to adjacent buildings. As these vibration is growing, there is occurred exaggerated forces and displacements of the track and line structure and it is causing the differential settlement. It is difficult to clarify the dynamic response characteristics of trackbed because of various environmental conditions. However, track irregularity be affected by ununiformed bearing capacity and its dynamic response, study for dynamic response characteristics is required to investigate the cause of track irregularity and countermeasure. This study was intended to evaluate the numerical analysis which exam the response analysis characteristic of ground vibration by shape of cutting and embankment transition zone. The original method of analysis were have to examine variables such as directions, angles, drain conditions, linear conditions. However, In the analysis there were to consider the effect of moving loads according to directions of cutting and embankment transition zone.

• Bulletin of the Korean Chemical Society
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• v.35 no.9
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• pp.2699-2703
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• 2014

We solve the Klein-Gordon equation with the modified Rosen-Morse potential energy model. The bound state energy equation has been obtained by using the supersymmetric shape invariance approach. The relativistic vibrational transition frequencies for the $6^1{\Pi}_u$ state of the $^7Li_2$ molecule have been computed by using the modified Rosen-Morse potential model. The calculated relativistic vibrational transition frequencies are in good agreement with the experimental RKR values.

• Journal of IKEEE
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• v.22 no.1
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• pp.61-67
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• 2018

We investigated theoretically the magnetic field dependence of the quantum optical transition of qusi 2-Dimensional Landau splitting system, in CdS and ZnO. In this study, we investigate electron confinement by square well confinement potential in magnetic field system using quantum transport theory(QTR). In this study, theoretical formulas for numerical analysis are derived using Liouville equation method and Equilibrium Average Projection Scheme (EAPS). In this study, the absorption power, P (B), and the Quantum Transition Line Widths (QTLWS) of the magnetic field in CdS and ZnO can be deduced from the numerical analysis of the theoretical equations, and the optical quantum transition line shape (QTLS) is found to increase. We also found that QTLW, ${\gamma}(B)_{total}$ of CdS < ${\gamma}(B)_{total}$ of ZnO in the magnetic field region B<25 Tesla.

• Journal of computational fluids engineering
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• v.15 no.1
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• pp.17-23
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• 2010

Performance improvements of the heat recovery steam generator(HRSG) can be achieved by improving the flow distribution of exhaust gases for a various type of different equipments. A number of design parameters are systematically investigated and their effects on an index of velocity deviation established. The parameters include the three shape of the transition duct and the wide range of the guide vane angles. The numerical results clearly reveal feature of the flow pattern in the transition duct, velocity deviation and pressure drop at tube bank part.