• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.10
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• pp.5974-5979
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• 2014

Lightweight parts with very uniform precision are manufactured by an indent method and the press technique has been improved. Upon assembly with an indent method, a deformation force due to the compressive force occurs between the pin and hole and the contact surface is affected by damage. Therefore, a 3 dimensional model was made using the CATIA program and the damage on the surface contacted with indent was estimated through the ANSYS program in this study. In the analysis result, the maximum load applied at the PCB plate was 21.3 N when the pin goes through the PCB plate. When PCB plate came out of the pin, the maximum load was 19.24 N. As the structural analysis result, the maximum equivalent stress of Pin 1 was 192.96MPa because the maximum stress occurs at Pin 1 among all parts of this study model. By examining the damage property of the contacted indent and applying this study result to the design of real indentation, the damage can be prevented and the durability can be estimated.

• Bulletin of the Korean Chemical Society
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• v.12 no.5
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• pp.499-504
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• 1991

EPR spectra of the high $T_c$ superconductor $YBa_2Cu_3O_{7-y}$ (YBCO) doped with $Pd^{2+} or Zn^{2+}$ have been measured at several temperatures and dopant concentrations. The spectral intensity of $YBa_2({Cu_{1-x}}{Pd_x})_3O_{7-y}$ is proportional to the dopant concentration. The behavior of $YBa_2(Cu_{1-x}Zn_x)_3O_{7-y}$ is quite different: the spectral intensity remains almost constant up to x=0.10 and then increases rapidly above x=0.10. The results are interpreted in terms of localized and antiferromagnetically spin-paired d holes in both CuO chain and planes. The $Pd_{2+}$ ion substitutes on the CuO chain consisting of "CuOCu dimers", and a $Cu_{2+}$ ion with an unpaired spin is gene rated for each $Pd_{2+}$ ion substituted. On the other hand, $Zn_{2+}$ substitutes on the CuO planes, and all or most of the spins in the two-dimensional plane manage to pair up in the region of low dopant concentration. When the dopant concentration exceeds a certain limit, it becomes more difficult for the spins to find partners, and the number of unpaired spins increases rapidly with increasing dopant concentration. The $Zn_{2+}$ ion is more effective than the $Pd_{2+}$ ion in suppressing the superconductivity of YBCO. This is attributed to the fact that $Zn_{2+}$ substitutes on the CuO planes which are mainly responsible for the superconductivity, while $Pd_{2+}$ substitutes on the CuO chain which is of secondary importance in the superconductivity.

• Atmosphere
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• v.31 no.4
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• pp.395-404
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• 2021

In order to investigate downslope windstorm by using more detailed observation, we observed 6 cases at 3 sites - Inje, Yongpyeong, and Bukgangneung - during "3-D Meteorological Observation Project in Yeongdong region of Gangwon province, South Korea in 2020." The results from analysis of the project data were as follows. First, AWS data showed that a subsidence inversion layer appeared in 800~700 hPa on the windward side and 900~850 hPa on the leeward side. Second, before strong wind occurred, the inversion layer had descended to about 880~800 hPa. Third, with mountain wave breaking, downslope wind was intensified at the height of 2~3 km above sea level. After the downslope wind began to descend, the subsidence inversion layer developed. When the subsidence inversion layer got close to the ground, wind peak occurred. In general, UM (Unified Model) GDAPS (Global Data Assimilation Prediction System) have had negative bias in wind speed around peak area of Taebaek mountain range, and positive bias in that of East Sea coast area. The stronger wind blew, the larger the gap between observed and predicted wind speed by GDAPS became. GDAPS predicted strong p-velocity at 0600 LST 25 Apr 2020 (4^th case) and weak p-velocity at 2100 LST 01 Jun 2020 (6^th case) on the lee-side of Taebaek mountain range near Yangyang. As hydraulic jump theory was proved, which is known as a mechanism of downslope windstorm in Yeongdong region, it was confirmed that there is a relationship between p-velocity of lee-side and wind speed of eastern slope of Taebaek mountain range.

• Journal of the Semiconductor & Display Technology
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• v.17 no.3
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• pp.41-45
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• 2018

Two-dimensional (2D) materials have been studied extensively due to their excellent physical, chemical, and electrical properties. Among them, we report the material and device characteristics of tin disulfide ($SnS_2$). To apply $SnS_2$ as a channel layer in a transistor, $SnS_2$ channels were formed by a stripping method and a transfer method. The limitation of this method is that it is difficult to produce uniform device characteristics over a large area. Therefore, we directly deposited $SnS_2$ by atomic layer deposition (ALD) and then performed lithography. This method was able to produce devices with repeatable characteristics over a large area. However, the $SnS_2$ film was damaged by the acetone used as a photoresist (PR) developer during the lithography process, with the electrical properties of mobility of $2.6{\times}10^{-4}cm^2/Vs$, S.S. of 58.1 V/decade, and on/off current ratio of $1.8{\times}10^2$. These results are not suitable for advanced electronic devices. In this study, we analyzed the effect of acetone on $SnS_2$ and studied the device process to prevent such damage. Using polyvinyl alcohol (PVA) as a passivation layer during the lithography process, the electrical characteristics of the $SnS_2$ transistor had $2.11{\times}10^{-3}cm^2/Vs$ of mobility, 11.3 V/decade of S.S, and $2.5{\times}10^3$ of the on/off current ratio, which were 10x improvements to the $SnS_2$ transistor fabricated by the conventional method.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.2
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• pp.38.3-38.3
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• 2018

We present the results of high-resolution near-IR spectral mapping toward the Orion KL outflow. In this study, we used the Immersion Grating Infrared Spectrometer (IGRINS) on the 2.7 m Harlan J. Smith Telescope at McDonald Observatory. IGRINS's large wavelength coverage over the H & K bands and high spectral resolving power (R ~ 45,000) allowed us to detect over 35 shock-excited ro-vibrational H2 transitions and to measure directly the gas temperature and velocity of the dense outflows. In our previous study toward the H2 peak 1 region in the Orion KL outflow, we identified 31 outflow fingers from a datacube of the H2 1-0 S(1) $2.122{\mu}m$ line and constructed a three-dimensional map of the fingers. The internal extinction (${\Delta}AV$ > 10 mag) and overall angular spread of the flow argue for an ambient medium with a high density (105 cm-3). In this presentation, we show preliminary results of additional mapping toward a remarkable chain of bows (HH 205 - HH 207) farther from the ejection center, and obtain a more clear view of the shock physics of a single isolated bullet that improves on the knowledge gained from observations of the more complex peak 1 region in our earlier study.

• Journal of the Korean GEO-environmental Society
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• v.22 no.4
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• pp.15-23
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• 2021

Various micropiles have been developed through research related to micropiles, which have been carried out with the increased use of micropiles. Among the micropile construction methods being developed, the triaxial micropile (tmp), which is recently developed for the purpose of increasing the horizontal bearing capacity (seismic resistance), is representative. The three-axis micropile has the advantage of a method that can resist horizontal load more effectively because three micropiles installed inclined on each axis resist horizontal load. However, there is a problem in effectively using this pile method due to insufficient research on the support characteristics of the triaxial group micropile. In order to effectively utilize the triaxial group micropile (tmp), it is required to evaluate the bearing capacity for the factors that affect the horizontal bearing capacity of the pile. Therefore, in this study, field horizontal loading Tests were performed for each load direction, field loading Tests were verified through three-dimensional finite element analysis, behavioral characteristics of triaxial micropiles were evaluated, and appropriate horizontal bearing capacity was analyzed in consideration of horizontal load directions.

• Journal of Broadcast Engineering
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• v.26 no.3
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• pp.258-268
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• 2021

Point cloud content is immersive content that represents real-world objects with three-dimensional (3D) points. In the process of acquiring point cloud data or encoding and decoding point cloud data, the resolution of point cloud content could be degraded. In this paper, we propose a method of progressively enhancing the resolution of sequential point cloud contents through inter-frame registration. To register a point cloud, the iterative closest point (ICP) algorithm is commonly used. Existing ICP algorithms can transform rigid bodies, but there is a disadvantage that transformation is not possible for non-rigid bodies having motion vectors in different directions locally, such as point cloud content. We overcome the limitations of the existing ICP-based method by registering regions with motion vectors in different directions locally between the point cloud content of the current frame and the previous frame. In this manner, the resolution of the point cloud content with geometric movement is enhanced through the process of registering points between frames. We provide four different point cloud content that has been enhanced with our method in the experiment.

• Progress in Medical Physics
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• v.33 no.1
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• pp.1-9
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• 2022

Purpose: To evaluate the effective volume of the Korea Research Institute of Standards and Science free air chamber (KRISS FAC) L1 used for the primary standard device of the low-energy X-ray air kerma. Methods: The mechanical dimensions were measured using a 3-dimensional coordinate measuring machine (3-d CMM, Model UMM 500, Carl Zeiss). The diameter of the diaphragm was measured by a ring gauge calibrator (Model KRISS-DM1, KRISS). The elongation of the collector length due to electric field distortion was determined from the capacitance measurement of the KRISS FAC considering the result of the finite element method (FEM) analysis using the code QuickField v6.4. Results: The measured length of the collector was 15.8003±0.0014 mm with a 68% confidence level (k=1). The aperture diameter of the diaphragm was 10.0021±0.0002 mm (k=1). The mechanical measurement volume of the KRISS FAC L1 was 1.2415±0.0006 cm³ (k=1). The elongated length of the collector due to the electric field distortion was 0.170±0.021 mm. Considering the elongated length, the effective measurement volume of the KRISS FAC L1 was 1.2548±0.0019 cm³(k=1). Conclusions: The effective volume of the KRISS FAC L1 was determined from the mechanically measured value by adding the elongated volume due to the electric field distortion in the FAC. The effective volume will replace the existing mechanically determined volume in establishing and maintaining the primary standard of the low-energy X-ray.

• The Journal of the Society of Stroke on Korean Medicine
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• v.24 no.1
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• pp.13-24
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• 2023

■Objectives This case study is to report the effects of Korean medicine on parkinsonism patient's Gait Disturbance. ■Methods During 12 days of hospitalization, the patient was treated by acupuncture, pharmaco-acupuncture, moxibustion, herbal medicine, especially Cheongsimyeonjatang-gamibang. In order to assess the change of symptoms, we used a 3-Dimensional(3D) gait analysis system, Unified Parkinson's Disease Rating Scale(UPDRS), analysis of gait video and self-evaluation of discomfort. ■Results After treatment, The improvements of walking pattern were observed in both objective analysis results of gait analysis system and subjective video analysis. And the UPDRS score decreased, especially Part III score decreased more than minimal clinically important difference(MCID). In addition, There was improvement in self assessment of the patient. ■Conclusion This study suggests that Korean medical treatment might be effective in motor disorder of parkinsonism patient.

• Journal of the Korean Geotechnical Society
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• v.40 no.3
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• pp.101-108
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• 2024

A system with the ability to recognize potential key blocks during tunnel construction by analyzing the rock face was developed in this study. This system predicts the formation of key blocks in advance and evaluates their safety factors. A laser scanner was used to collect a three-dimensional point cloud of the rock face, which was then utilized to model the excavation surface and derive the joint surfaces. Because joint surfaces have specific strikes and dip angles, the key blocks formed by these surfaces are deduced through iterative calculations, and the safety factor of each key block can be calculated accordingly. The model experiments confirmed the accuracy of the system's output in terms of the joint surface characteristics. By inputting the joint surface information, the calculated safety factors were compared with those from the existing commercial software, demonstrating stable calculation results within a 1% error margin.