• Journal of the Korean Wood Science and Technology
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• v.37 no.2
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• pp.128-136
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• 2009

Curved glued laminated timber (glulam) is rapidly coming into the domestic modern timber frame buildings and predominant in building construction. The radial stress is frequently occurred in curved beams and is a critical design parameter in curved glulam. Three models, Wilson equation, Exact solution and Approximation equation were introduced to determine the radial stress of curved glulam under pure bending condition. It is obvious that radial stress distribution between small radius and large radius was different due to slight change of neutral plane location to center line. If the beam design with extremely small radius, it should be considered to determine the exact location of maximum radial stress. The current standard KSF 3021 was reviewed and would be considered some adjustment determining the optimum radius in curved glulam. Current design principle is that the stress factor is given by the curvature term only in constant depth of the beam, but like tapered or small radius of beams, the stress factor by Wilson equation was underestimated. So current design formula should be considered to improvement for characterizing the radial stress factor under pure bending condition.

• Transactions on Electrical and Electronic Materials
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• v.8 no.5
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• pp.191-195
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• 2007

We investigated photoluminescence characteristics of ZnO nano needle-like rods grown on a c-plane $AL_2O_3$ substrate by the hot wall epitaxy method. The nano-rods were vertically well aligned along the ZnO c-axis. The diameters of the ZnO nano-rods ranged from 20 nm to 30 nm and their lengths were between 600 and 700 nm. In the photoluminescence spectrum at 10 K, the exciton emission bound to the neutral donor dominated while defect related emission was weakly observed. With a further increase of temperature, the free exciton emission appeared and eventually became dominant at room temperature.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.05a
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• pp.49-50
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• 2019

In the case of High-rise buildings, it has a problem by stack effect that rise of vertical height. Especially in case of fire, it need to the consideration of stack effect that it has bigger than general. Therefore in this study, we used to the Contamw and FDS simulation for analysis of stack effect and pressure distribution characteristic in fire. As a result the Contamw simulation shows the pressure distribution by stack effect in general high-rise buildings. However, in case of fire, the height of the neutral plane is lowered and stack effect is larger. Therefore, it is necessary to multiply analyze the temperature distribution and the stack effect in fire.

• Bulletin of the Korean Chemical Society
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• v.29 no.9
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• pp.1761-1764
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• 2008

The adsorption structure and binding of maleimide (MI) and succinimide (SI) on silver nanocolloidal surfaces have been comparatively investigated by means of pH-varied surface-enhanced Raman scattering (SERS). The two molecules appeared not to adsorb onto Ag surfaces at pH values below 5. The appearance of a ring ν (CH) band at ~3100 $cm^{-1}$ denoted the standing geometry of MI’s aromatic ring on Ag. The absence or weakness of in-plane vibrational modes of MI and SI also supported a perpendicular orientation of MI and SI on Ag from the electromagnetic selection rule. Density functional theory (DFT) calculations were employed to examine the vibrational frequencies of MI’s and SI’s neutral and anionic states.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.433-436
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• 2004

The safety of buildings is generally estimated by analyzing a plane frame ignoring a minor bending moment. In this paper, uncertainties of reinforced concrete shear wall subjected to a biaxial bending are considered. First, major parameters are selected from all parameters of general shear wall design to perform a reliability analysis in their practical ranges, means and standard derivations of selected design parameters for the reliability analysis are calculated by a data mining as a simulation method. The bi-section method is used to find inclined neutral axis and its limit state using MATLAB subjected to the concept on strength design method. The reliability index $\beta$ as a safety index is calculated based on AFOSM(Advanced First-Order Second Moment) method. Also, if target reliability index $\beta_T$ is decided by an engineer an amount of reinforcement can be calculated by subtracting the reliability index $\beta$ from the target reliability index $\beta_T$.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.1
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• pp.17-22
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• 2011

ZnO-based thin-film transistors (TFTs) have been fabricated and the mechanical characteristics of electric circuits, such as stress, strain, and deformation are analyzed by the finite element method (FEM). In this study, a mechanical-stability design guide for such systems is proposed; this design takes into account the stress and deformation of the bridge to estimate the stress distribution in an $SiO_2$ film with 0 to 5% stretched on 0.5-${\mu}m$-thick. The predicted buckle amplitude of $SiO_2$ bridges agrees well with experimental results within 0.5% error. The stress and strain at the contact point between bridges and a pad were measured in a previous structural analysis. These structural analysis suggest that the numerical measurement of deformation, SU-8 coating thickness for Neutral Mechanical Plane (NMP) and ITO electrode size on a dielectric layer was useful in enhancing the structural and electrical stabilities.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.3
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• pp.224-230
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• 2019

The purpose of this study is to investigate the effect of the hip positions in frontal plane on abdominal muscle activities during bridging exercise. Twenty six subjects who have healthy conditions were asked to perform bridging exercise in three starting positions which are hip abduction, neutral and hip adduction. We used surface electromyography to compare the activities of both external oblique, internal oblique and rectus abdominis muscle. We analyzed the data by using repeated one way ANOVA, The alpha level was set at 0.05. The results showed that the muscle activities of both sides of external oblique, and internal oblique were significantly different among three starting positions. The activity of both sides of rectus abdominis were insignificantly different among three positions. The muscle activities of both sides of external oblique muscle and left internal oblique in bridging exercise with hip adduction position were significantly greater than hip neutral positions. The muscle activity of right internal oblique in bridging exercise with hip abduction positions. Our results suggest that bridging exercise with hip adduction position is recommended to lumbar stabilization exercise and the factor of hip position is important for controlling exercise intensity when designing bridging exercise program.

• Clinics in Shoulder and Elbow
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• v.1 no.2
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• pp.186-192
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• 1998

This study was performed to evaluate the influences of the passive glenohumeral rotation on the scapulothoracic motion. We took anteroposterior radiograms of the right shoulders including the thoracic vertebrae with supine position in 10 normal male adults, at 0 degree abduction, 45 degrees abduction and 90 degrees abduction in scapular plane and in neutral rotation, maximal internal rotation and maximal external rotation in each abduction view. The scapulothoracic motion was measured as the distances between the vertical line drawn from the spinous process of the 7th cervical vertebra and the inferior and superior angles of the right scapula respectively. At 0 degree abduction, the distances were not changed in internal rotation relative to neutral rotation, but decreased significantly in external rotation, that is, the scapula shifts medially on external rotation. At 45 degrees abduction, the distances were increased significantly only in internal rotation, that is, the scapula shifts laterally on internal rotation. At 90 degrees abduction, the scapula rotated laterally on internal rotation and medially on external rotation. In conclusion, when a physician examines the rotation of the shoulder joint, he cannot exclude the scapulothoracic motion just by examining the patient with supine position. And we concluded that the rotatory movement of the shoulder is not solely contributed to the glenohumeral motion.

• Journal of the Korean Geotechnical Society
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• v.21 no.5
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• pp.65-74
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• 2005

The negative skin friction on piles, which are installed in currently consolidating soft deposits, creates significant problems on the stability of pile foundations. This study investigated whether or not the pile foundation designs were appropriate in soft deposits with large amount of consolidation settlement. The final settlements of the grounds along the pile depth were estimated by the soil parameters obtained from the laboratory tests and by the field-measured settlement curves, if they were available. The displacement of the piles along the pile depth was estimated by both the load transfer method and the numerical method. Both methods gave similar locations of neutral planes and magnitudes of the maximum axial forces on the piles. The movements of the ground and the piles were compared to calculate the down drag acting on piles. For the piles whose bearing capacities were less than the design loads including the down drag, slip layer coatings and/or incrementing of the pile penetration depth into the bearing stratum were proposed to improve the pile capacities.

• Journal of Korean Society of Steel Construction
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• v.28 no.5
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• pp.365-371
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• 2016

In the case of the superstructure which is consist of two I girders and slab, the section can behave as II section, so that the neutral axis with respect to out of plane direction flexure can be regarded as major axis. Therefore in-plane flexural mode might govern the free vibration mode. Meanwhile, horizontally curved girders always experience not only bending moments but also torsional moments although the primary load is usually supposed to be gravitational load. The interaction due to bending and torsional moments make the behavior complicated and torsional mode may govern the free vibration mode. In other words, structure can have different dynamic characteristic due to its initial curvature. In this research, using 3-dimensional sell elements, free-vibration analyses are carried out due to initial curvature. The analysis models are assumed to be composite and non-composite and finally natural frequency and eigen mode are discussed.