• Steel and Composite Structures
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• 제49권5호
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• pp.533-546
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• 2023

Cost-effective solutions provided by composite construction are gaining popularity which, in turn, promotes the appearance on the market of new types of composite sections that allow not only to take advantage of the synergy of steel and concrete working together at room temperature, but also to improve their behaviour at high temperatures. When combined with high performance materials, significant load-bearing capacities can be achieved even with reduced cross-sectional dimensions. Steel-reinforced concrete-filled steel tubular (SR-CFST) columns are one of these innovative composite sections, where an open steel profile is embedded into a CFST section. Besides the renowned benefits of these typologies at room temperature, the fire protection offered by the surrounding concrete to the inner steel profile, gives them an enhanced fire performance which delays its loss of mechanical capacity in a fire scenario. The experimental evidence on the fire behaviour of SR-CFST columns is still scarce, particularly when combined with high performance materials. However, it is being much needed for the development of specific design provisions that consider the use of the inner steel profile in CFST columns. In this work, a new experimental program on the thermo-mechanical behaviour of SR-CFST columns is presented to extend the available experimental database. Ten SR-CFST stub columns, with circular and square geometries, combining high strength steel and concrete were tested. It was seen that the circular specimens reached higher failure times than the square columns, with the failure time increasing both when high strength steel was used at the embedded steel profile and high strength concrete was used as infill. Finally, different proposals for the reduction coefficients of high performance materials were assessed in the prediction of the cross-sectional fire resistance of the SR-CFST columns.

• 천문학회지
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• 제38권2호
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• pp.191-195
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• 2005

We used Subaru observations of A1689 (z = 0.183) to derive an accurate, model-independent mass profile for the entire cluster, r$\le$2Mpc/h, by combining magnification bias and distortion measurements. The projected mass profile steepens quickly with increasing radius, falling away to zero at r${\~}$1.0Mpc/h, well short of the anticipated virial radius. Our profile accurately matches onto the inner profile, r $\le$200kpc/ h, derived from deep HST / ACS images. The combined ACS and Subaru information is well fitted by an NFW profile with virial mass, $(1.93 \pm 0.20) {\times}10^{15} M_{\bigodot}$, and surprisingly high concentration, $C_{vir} = 13.7^{+1.4}_{-1.1}$, significantly larger than theoretically expected ($C_{vir} {\le}4$), corresponding to a relatively steep overall profile. These results are based on a reliable sample of background galaxies selected to be redder than the cluster E/SO sequence. By including the faint blue galaxy population a much smaller distortion signal is found, demonstrating that blue cluster members significantly dilute the true signal for r $\le$ 400kpc/ h. This contamination is likely to affect most weak lensing results to date.

• Wind and Structures
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• 제39권1호
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• pp.31-45
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• 2024

This paper examines the flow characteristics around an inclined prism with a U-shaped cross-section ("U-profile") and investigates the connection between the flow and flow-induced vibrations. The study employs a combined approach that involves wind tunnel experiments and computational fluid dynamics (CFD) using an unsteady Reynolds-averaged Navier-Stokes (RANS) turbulence model. Distinct vortex formation patterns are observed in the flow field surrounding the stationary inclined profile. When the cavity of the profile faces away from the incoming flow, large vortices develop behind the profile. Conversely, when the cavity is oriented towards the oncoming flow, these vortices form within the cavity. Notably, due to the slow movement of these large vortices through the cavity, the frequency at which vortices are shed in the negative inclination case is lower compared to the positive inclination, where they form in the wake. Wind tunnel experiments reveal an intermittent transition between the two vortex formation patterns at zero inclination. Large vortices sporadically emerge both in the cavity and behind the profile. The simulation results demonstrate that when these large vortices occur at a frequency close to the structure's natural frequency, they induce prominent pitch vibrations. This phenomenon is also sought after and presented in coupled vibration experiments. Additionally, the simulations indicate that when the natural frequency of the structure is considerably lower than the vortex shedding frequency, this type of vibration can be observed.

• 한국정밀공학회지
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• 제33권3호
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• pp.207-216
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• 2016

A gerotor is suitable for miniature manufacturing because it has high discharge per 1 cycle and a simple structure, while also being widely used for lubrication oil of engines and as a hydraulic source of automatic transmission. In the automobile industry, improvements in fuel efficiency and noise reduction have recently come to the fore. It has also been necessary to continuously improve the flow rate and noise of internal gear pumps for better fuel efficiency through optimal gerotor and port shape design. In this study, to develop an optimal gerotor with a new lobe shape, 2-ellipses-combined, the equation of the lobe shape was derived, and CFD analysis results were compared for 2-ellipses with those of the previous gerotors (3-ellipses and ellipse1-involuteellipse2). A performance test for the oil pump with the optimal rotor (2-ellipses) was carried out and showed good agreement with the results obtained from CFD analysis.

• 약학회지
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• 제56권6호
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• pp.366-371
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• 2012

In this present study, we determined whether or not there is an immunoadjuvant effect of ochnaflavone, a biflavone isolated from Lonicera japonica. As an antigenic source, the cell wall (CACW) of Candida albicans, a fungal pathogen, was used. CACW consists of 95% carbohydrate (mannan). In the experiments, BALB/c mice were immunized with emersion forms of CACW combined with or without ochnaflavone (Och) in the presence of IFA containing mineral oil or CACW alone. Then, the amounts of antisera collected from these mice groups were measured by the ELISA method. Data from these experiments showed that CACW combined with Och (CACW/Och/IFA) provoked the production of antisera app. 2.2 or 5 times more than the corresponding CACW/IFA or CACW alone (CACW/DPBS), respectively, in mice (P<0.05). We further examined the immune response type induced by Och. Analysis of the values of the IgG1/IgG2a ratios obtained from IgG isotyping revealed that Och induced Th2-immunity more dominantly than Th1. This finding was confirmed by cytokine profile. CACW/Och/IFA formulation induced IL-4 (Th2-type cytokine) more than IFN${\gamma}$ (Th1-type cytokine) as compared with CACW/IFA and CACW/DPBS formulations (P<0.05). All data combined, Och appears to have an immunoadjuvant activity that may convert Th1 immunity into Th2 immunity.

• 한국멀티미디어학회논문지
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• 제20권11호
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• pp.1720-1728
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• 2017

Active shape model is widely used in the field of image processing especially on arbitrary meaningful shape extraction from single gray level image. Cootes et. al. showed efficient detection of variable shape from image by using covariance and mean shape from learning. There are two stages of learning and testing. Hahn applied enhanced shape alignment method rather than using Cootes's rotation and scale scheme. Hahn did not modified the profile itself. In this paper, the method using directional one dimensional profile is proposed to enhance Cootes's one dimensional profile and the shape alignment algorithm of Hahn is combined. The performance of the proposed method was superior to Cootes's and Hahn's. Average landmark estimation error for each image was 27.72 pixels and 39.46 for Cootes's and 33.73 for Hahn's each.

• Journal of the Korean Wood Science and Technology
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• 제48권5호
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• pp.581-590
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• 2020

Pulp refining is the major way to alter the properties of fibers and formed paper. Different combinations of the bar profile of the rotor and stator during low consistency refining processes directly affect the properties of the paper. In this study, a mixture of softwood and hardwood pulp was refined by varying the bar angle of the stator while that of the rotor is fixed at 0º. The pulp samples were collected at different refining times. Then, the pulp and paper properties, such as beating degree, fiber external fibrillation, and tensile and tear indexes were measured to explore the effects of the combined refining plates at different bar angles on paper properties. The results of the experiment show that the combined refining plate of 0º and 5º recorded the most significant improvement in the pulp beating degree and fiber external fibrillation. This consequently increased the fiber bonding area, which in turn, improved both the tensile and the tear indexes of the paper. Also, the influence of the combined refining plates with a larger bar angle on the paper properties was weaker compared to that of smaller angles. This study not only provides ideas for the bar profile design but also improves the optimal selection of refining plates.

• 한국정보과학회논문지:소프트웨어및응용
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• 제31권8호
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• pp.1062-1072
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• 2004

협력적 여과 시스템은 ｛사용자-문서｝의 행렬을 기반으로 사용자에게 웹 문서를 추천하는 데 있어서 효율적인 시스템이다. 그러나 협력적 여과 시스템은 초기 평가 문제와 희박성으로 인하여 추천의 정확도가 저하된다는 단점을 갖는다. 본 논문에서는 협력적 여과 시스템의 희박성과 초기 평가 문제를 해결하기 위하여 사용자 프로파일을 생성시킴으로써 자동으로 선호도를 평가하는 방법을 제안한다. 본 논문에서 사용하는 프로파일은 협력적 여과 시스템에서의 ｛사용자-문서｝ 행렬을 기반으로 생성된 사용자 프로파일에 내용 기반 여과 시스템에서 연관 피드백을 이용하여 생성한 사용자 프로파일을 상호정보의 방법에 의해 병합함으로써 생성한 내용 기반 협력적 사용자 프로파일이다. 생성한 내용 기반 협력적 사용자 프로파일을 정규화시키고, 정규화한 프로파일을 협력적 여과 시스템의 ｛사용자-문서｝ 행렬에 반영함으로써 자동으로 선호도를 평가한다. 제안된 방법은 사용자가 웹 문서에 대해서 선호도를 평가한 데이터베이스에서 평가되었으며, 기존의 방법보다 보다 효율적임을 증명한다.

• Journal of the Optical Society of Korea
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• 제18권3호
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• pp.236-243
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• 2014

Surface profiling and film thickness measurement play an important role for inspection. White light interferometry is widely used for engineering surfaces profiling, but its applications are limited primarily to opaque surfaces with relatively simple optical reflection behavior. The conventional bucket algorithm had given inaccurate surface profiles because of the phase error that occurs when a thin-film exists on the top of the surface. Recently, reflectometry and white light scanning interferometry were combined to measure the film thickness and surface profile. These techniques, however, have found that many local minima exist, so it is necessary to make proper initial guesses to reach the global minimum quickly. In this paper we propose combing reflectometry and white light scanning interferometry to measure the thin-film thickness and surface profile. The key idea is to divide the measurement into two states; reflectometry mode and interferometry mode to obtain the thickness and profile separately. Interferogram modeling, which considers transparent thin-film, was proposed to determine parameters such as height and thickness. With the proposed method, the ambiguity in determining the thickness and the surface has been eliminated. Standard thickness specimens were measured using the proposed method. Multi-layered film measurement results were compared with AFM measurement results. The comparison showed that surface profile and thin-film thickness can be measured successfully through the proposed method.

• Structural Engineering and Mechanics
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• 제84권5호
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• pp.591-604
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• 2022

A gravity wall combined with an anchoring lattice frame (a combined retaining structure) is adopted at a typical engineering site at Dali-Ruili Railway Line China. Where, the combined retaining structure supports a soil deposit covering on different inclined rock slopes. With an aim to investigate and compare the effects of inclined rock slopes on the response of combined retaining structure under seismic excitation, three groups of shaking table tests are conducted. The rock slopes are shaped as planar surfaces inclined at angles of 20°, 30°, and 40° with the horizontal, respectively. The shaking table tests are supplemented by dynamic numerical simulations. The results regarding the horizontal acceleration response, vertical acceleration response, permanent displacement mode, and axial anchor force are comparatively examined. The acceleration response is more susceptible to outer structural profile of combined retaining structure than to inclined angle of rock slope. The permanent displacement decreases when the inclined angle of the rock slope increases within a range of 20°-40°. A critical inclined angle of rock slope exists within a range of 20°-40°, and induces the largest axial anchor force in the combined retaining structure.