• Journal of the Korean Wood Science and Technology
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• v.44 no.1
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• pp.40-47
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• 2016

Instead of metal connector generally used on the structural glued laminated timber rahmen joints, the GFRP reinforced laminated plates combining veneer and GFRP (Glass Fiber Reinforced Plastic) and bonded type GFRP rod were used as the connectors. As a result of moment resistance performance evaluation on the joint part applied with these connectors, the yield moment of specimen using the GFRP reinforced laminated plates and GFRP rod pin was measured 4 % lower in comparison to the specimen (Type-1) using the metal connectors, but the initial rotational stiffness was measured 29% higher. Also, the yield moment and rotational stiffness of the specimen using the GFRP-reinforced laminated plates and wood (Eucalyptus marginata) pin showed were measured 11% and 56% higher in comparison to the Type-1 specimen, showing the best performance. It was also confirmed through the failure shape and perfect elasto-plasticity analysis that it showed ductility behavior, not brittle fracture, from the shear resisting force by the pin and the bonding strength increased and the unification of member was carried out. On the other hand, in case of the specimen bonded with GFRP rod, it was impossible to measure the bonding performance or it was measured very low due to poor bonding.

• Progress in Medical Physics
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• v.24 no.4
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• pp.315-322
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• 2013

The aim of this work is to verify the self-quality assurances in medical institutions in Korea through the external audits by the group of experts and have a mutual discussion of the systematic problems. In order to validate the external audits 30 of 80 medical institutions across the nation were picked out considering the regional distribution and the final 25 institutions applied voluntarily to take part in this work. The basic rules were setup that any information of the participants be kept secrete and the measurements be performed with the dosimetry system already verified through intercomparision. The outputs for 2 or more photon beams, the accuracy of gantry rotation and collimator rotation and the poistional accuracy of MLC movement were measured. The findings for the output measurement showed the differences of -0.8%~4.5%, -0.79%~3.01%, and -0.7%~0.07% with respect to that of the verified dosimetry system for the 6MV, 10MV, and 15MV, respectively. For the reference absorbed dose 8 (16%) of 50 photon beams in 25 medical institutions differed 2.0% or greater from the reference value. The coincidences of Field size with x-ray beam and radiation isocenters of Gantry roration and collimator rotation gave the results of within ${\pm}2$ mm for every institute except 2 institutions. The positional accuracy of MLC movement agreed to within ${\pm}1$ mm for every institute. For the beam qualities of 6 MV photon beams kQ values showed the distribution within 0.4% between maximum and minimum. For the protocols 21 institutions (84%) used absorbed dose to water based protocol while 4 insitutions (16%) used air kerma based one. 22 institutions employed the SSD technique while 3 institutions did the SAD one. External audit plays an important role in discovering the systematic problems of self-performing Quality Assurances and having in depth discussion for mutual complementation. Training experts of international level as well as national support system are required so that both the group of experts of medical physicists and government laboratory could perform together periodical and constant external audits.

• Anatomy & Biological Anthropology
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• v.31 no.4
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• pp.133-142
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• 2018

3D histology is a imaging system for the 3D structural information of cells or tissues. The synchrotron radiation propagation phase contrast micro-CT has been used in 3D imaging methods. However, the simple phase contrast micro-CT did not give sufficient micro-structural information when the specimen contains soft elements, as is the case with many biomedical tissue samples. The purpose of this study is to develop a new technique to enhance the phase contrast effect for soft tissue imaging. Experiments were performed at the imaging beam lines of Pohang Accelerator Laboratory (PAL). The biomedical tissue samples under frozen state was mounted on a computer-controlled precision stage and rotated in $0.18^{\circ}$ increments through $180^{\circ}$. An X-ray shadow of a specimen was converted into a visual image on the surface of a CdWO4 scintillator that was magnified using a microscopic objective lens(X5 or X20) before being captured with a digital CCD camera. 3-dimensional volume images of the specimen were obtained by applying a filtered back-projection algorithm to the projection images using a software package OCTOPUS. Surface reconstruction and volume segmentation and rendering were performed were performed using Amira software. In this study, We found that synchrotron phase contrast imaging of frozen tissue samples has higher contrast power for soft tissue than that of non-frozen samples. In conclusion, synchrotron radiation propagation phase contrast cryo-microCT imaging offers a promising tool for non-destructive high resolution 3D histology.

• Journal of the Korean Chemical Society
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• v.42 no.5
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• pp.512-518
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• 1998

In this study, various thermodynamic and hydrodynamic parameters characterizing the solution properties of polyethylene ionomer particles in water were determined at $30^{\circ}C$ by means of light scattering and viscosity measurements. Based on the experimental data, we investigated the solution behavior of three kinds of polyethylene ionomers, which are different in composition of the pendant ionic groups of COOK, COOH and $CONH_{2}$, and characterized their particle properties. Ionomers containing 7.6 mol% potassium salt only behave as flexible coils in a relatively good solvent state. On the other hand, two ionomers containing 3.8 mol% amide group together with potassium salt form the compact particles. In addition, the concentration dependence of the effective diffusion coefficient $(D_{eff})$ and the reduced viscosity of the latter ionomers showed the opposite trend from the former, indicating that the composition of the pendant ionic groups have a great influence on the interparticle interaction of ionomers formed in water.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.8
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• pp.1083-1090
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• 2012

Copper alloys are widely used for casting materials including ship's propellers and pump impellers as they provide high corrosion resistance. In addition, the demand for these alloys is increasing with rapid growth of offshore structures and exploitation of various substitute energy sources. However, they require regular maintenance because of erosion and cavitation damages induced by exposure to marine environment at high speed flows for a long period of time. Water cavitation peening have received attention as one of surface modifications for durability improvement of the copper alloys. This is a environment friendly technology without influence of heat and easily applicable to casting materials. In this research, water cavitation peening was employed in distilled water for copper alloy castings as a function of time and evaluation of corrosion resistance was followed in seawater for the modified surface by using electrochemical methods. The result suggests that the water cavitation peening for 2 minutes was found to be the optimal peening parameter in terms of durability and corrosion resistance.

• Journal of Chest Surgery
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• v.31 no.6
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• pp.624-628
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• 1998

Postpneumonectomy syndrome is a rare and delayed complication of left pneumonectomy in most patients with normal mediastinal vascular anatomy. This syndrome is characterized by dyspnea and recurrent pulmonary infection in the remaining right lung that typically occur within the first postoperative year. The condition is believed to be secondary to postsurgical changes that include a marked shift of the mediastinum to the left, clockwise rotation of the heart and great vessels, and herniation of the right lung into the left anterior thorax. These changes lead to compression of the trachea or right main bronchus among the thoracic spine and the right pulmonary artery. We report a case of postpneumonectomy syndrome in 15 year-old girl that followed by left pneumonectomy for bronchiectasis 6 years ago. We have inserted an expandable prosthesis in the left thoracic cavity posterior to the heart. After implantation of an expandable prosthesis, an anatomic reposition of the shifted mediastinum was achieved, which resulted in instantaneous and sustained relief. The post-operative course was uneventful and the patient was followed in OPD from after discharge to now.

• Journal of Industrial Convergence
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• v.17 no.4
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• pp.15-20
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• 2019

Augmented reality is used in various fields such as culture, education, military, medical. This is a method of recognizing information of an augmented object on the camera. Exhibitions and educational contents for children are already produced in various ways. This research showed the developed contents deliver cultural property information using augmented reality. 'Galgibi AR' and 'Jang Young-sil's Invention AR' allow you to experience cultural assets up close. 'Galgibi AR' is the experience content in the form of 3D blocks. It makes to understand the structure of the zeolite, Galgibi. 'Jang Young-sil's Invention AR' make you to watch out four objects in detail by zooming in, zooming out and rotating. It can also take pictures with the inventions. Both contents implement what we want to deliver accurately through simple content. They increase the enjoyment of cultural heritage through experience contents. This research addressed to help the cultural property information spread to the public by using Augmented Reality.

• Applied Microscopy
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• v.33 no.1
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• pp.49-58
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• 2003

The ${\alpha}-{\beta}$ phase transition of titanium was investigated through in-situ EF-TEM heating experiments. Three different areas of a titanium foil were observed to minimize statistical errors. Systematic recording of diffraction patterns and images was carried out from $RT{\rightarrow}600^{\circ}C{\rightarrow}900^{\circ}C{\rightarrow}RT$ on each area. The following results were obtained: (1) Transition of titanium takes place very rapidly at $900^{\circ}C$. Two phases of titanium, ${\alpha}\;and\;{\beta}$, coexist at this temperature. (2) The transited ${\beta}$-phase appears in the form of twinned plates which are arranged in rotation relationship one another. (3) Analyses of electron diffraction patterns and EDS data indicate that the thermal oxidation layer is gradually formed on the surface of titanium above $900^{\circ}C$, which hinders the reversible ${\beta}{\rightarrow}{\alpha}$ phase transition upon cooling.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.28 no.4
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• pp.202-211
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• 2016

This study aims to analyze seismic responses of suction foundations for offshore wind turbine. For this purpose, dynamic centrifuge model tests were carried out. The skirt length of the suction foundation is a critical element for bearing mechanism against environmental loads. Thus, dynamic centrifuge model tests were performed and analyzed for three suction foundation models with the ratios of skirt length to suction foundation diameter of 0.5, 0.75, and 1 installed in dense sand. As results, the acceleration amplification at the suction foundation, residual settlement, and residual tilting angle were compared.

• Transactions of the KSME C: Technology and Education
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• v.5 no.2
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• pp.89-95
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• 2017

LCD robot vertical frame lets a arm assembly with glass substrate move up and down, so it must have high stiffness and strength. We applied new manufacturing process by using design optimization process such as topology and size optimization in order to satisfy the request of high stiffness and light weight. The proposed model should be evaluated for endurance strength. Therefore fatigue assessment for weak point of aluminum welding area of vertical frame studied with hot spot stress approach. And the actual stress measuring from test was compared and evaluated with the dynamic stress calculated from multi-body dynamics considering flexible body.