• Journal of Institute of Convergence Technology
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• v.1 no.1
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• pp.41-47
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• 2011

With the world-wide demand on the emission minimization, the needs on the diesel aftertreatment devices with high efficiency are also increasing. In order to effectively develop or design a high-performance diesel particulate filter, a clear understanding on the deposition and regeneration mechanism is required. In the present study, a theory on the lumped parameter model for wall-flow type diesel particulate filters is described focusing on the deposition efficiency, pressure drop inside the filter. The fourth order explicit Runge-Kutta method is utilized for the mass flow rate computation. Engine operation modes with controlled and uncontrolled regeneration options are selected. The computational lumped parameter model is validated by comparing the computed results with the measured data.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.324-330
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• 2012

Dual bell nozzle is one of the most promising choices among the altitude adaptation nozzles. This facilitates having a forced, steady and symmetrical separation at lower altitudes and a controlled flow separation at the wall inflection point which prevents the generation of dangerous side loads. In order to ensure the attached flow in the second bell, a clear understanding of the flow transition is required. Hence the motivation of our study is to arrive at an optimum profile for the second bell, which allows a sudden and controlled transition. In this work, we designed the first bell using the conventional MoC and the second bell using an inverse MoC, imposing a pressure gradient constraint. A CFD analysis is also carried out. It is found that the separation point is near the inflection point within one fourth of the extension length or it is near the exit.

• Cartoon and Animation Studies
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• s.49
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• pp.633-649
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• 2017

The purpose of this study is to conceptualize the changing aspects of human freedom of observation and viewing as the visual media evolves from film to 3D stereoscopic film and VR. The purpose of this study is to conceptualize the aspect of freedom and viewing aspect from the viewpoint of genealogy. In addition, I will identify the media aesthetic characteristics of VR and identify the identity and ontology of VR. Media has evolved around the most artificial sense of human being. There is a third visual space called screen at the center of all the reproduction devices centering on visual media such as painting, film, television, and computer. In particular, movies, television, and video screens, which are media that reproduce moving images, pursue perfect fantasy and visual satisfaction while controlling the movement of the audience. A mobilized virtual gaze was secured on the assumption of the floating nature of the so-called viewers. The audience sees a cinematic illusion with a view while seated in a fixed seat in a floating posture. They accept passive, passive, and passively without a doubt the fantasy world beyond the screen. But with the advent of digital paradigm, the evolution of visual media creates a big change in the tradition of reproduction media. 3D stereoscopic film predicted the extinction of the fourth wall, the fourth wall. The audience is no longer sitting in a fixed seat and only staring at the front. The Z-axis appearance of the 3D stereoscopic image reorganizes the space of the story. The viewer's gaze also extends from 'front' to 'top, bottom, left, right' and even 'front and back'. It also transforms the passive audience into an active, interactive, and experiential subject by placing viewers between images. Going one step further, the visual media, which entered the VR era, give freedom to the body of the captive audience. VR secures the possibility of movement of visitors and simultaneously coexists with virtual space and physical space. Therefore, the audience of the VR contents acquires an integrated identity on the premise of participation and movement. It is not a so-called representation but a perfection of the aesthetic system by reconstructing the space of fantasy while inheriting the simulation tradition of the screen.

• Journal of Periodontal and Implant Science
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• v.41 no.6
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• pp.285-292
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• 2011

Purpose: The aim of this study was to elucidate the effect of a bovine hydroxyapatite/collagen (BHC) block in one-wall intrabony periodontal defects in dogs. Methods: A one-wall intrabony periodontal defect (4 mm wide and 5 mm deep) was prepared bilaterally at the mesial side of the mandibular fourth premolar in five beagle dogs. After thorough root planing, block-type BHC ($4{\times}5{\times}5$ mm) was placed on one side. The contralateral defect area did not receive any material as a sham-surgery control. Histological analysis of the sites was performed after an 8-week healing period. Results: Two of five samples in the experimental group healed well without dissipation of the graft materials, and histological analysis revealed excellent regeneration of the periodontal tissues. However, most of the grafted materials had been displaced in the other three samples, leaving only a small portion of the graft. The measured parameters exhibited large standard deviations, and the mean values did not differ significantly between the experimental and sham-surgery control sides. Conclusions: The application of BHC alone-without a barrier membrane-to wide, one-wall intrabony periodontal defects yielded inconsistent results regarding both periodontal regeneration and substantivity of the graft materials. Thus, the use of a barrier membrane for noncontained-type defects is recommended to improve the stability of the grafted material, and to condense it.

• Journal of Periodontal and Implant Science
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• v.38 no.1
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• pp.51-58
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• 2008

Purpose: In dental clinical fields, various periodontal membranes are currently used for periodontal regeneration. The periodontal membranes are categorized into two basic types: resorbable and non-resorbable. According to the case, clinician select which membrane is used. Comparing different membranes that are generally used in clinic is meaningful. For this purpose, this study evaluates histological effects of various membranes in canine one wall intrabony defect models and it suggest a valuation basis about study model. Material and Method: The membranes were non-resorbable TefGen $Plus^{(R)}$, resorbable Gore Resolut $XT^{(R)}$ and resorbable $Osteoguide^{(R)}$. One wall intrabony defects were surgically created at the second and the mesial aspect of the fourth mandibular premolars in either right or left jaw quadrants in two dogs. The animals were euthanized 8 weeks post-surgery when block sections of the defect sites were collected and prepared for histological evaluation. Results: 1. While infiltration of inflammatory cells were observed in control, TefGen $Plus^{(R)}$ and Gore Resolut $XT^{(R)}$, it was not observed in $Osteoguide^{(R)}$. 2. TefGen $Plus^{(R)}$ had higher integrity than others and $Osteoguide^{(R)}$ was absorbed with folding shape. Gore Resolut $XT^{(R)}$ was divided everal parts during resorbtion and it was also absorbed from inside. 3. Quantity of new bone and new cementum was not abundant in all membranes. 4. For histologic evaluation of membranes we should consider infiltration of inflammatory, migration of junctional epithelium, integrity of membrane, quantity of new bone and new cementum, connective tissue formation and aspect of resorption. Conclusion: This histologic evaluation suggests that $Osteoguide^{(R)}$ provides periodontal regenerative environment with less inflammatory state. It is meangful that this study model suggests a valuation basis about other study model.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.6
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• pp.888-898
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• 1998

The present study investigated the effects of the experimental parameters on the cooling characteristics of the multichip module cooled by the indirect liquid cooling method using water and paraffin slurry. The experimental parameters are mass fraction of 2.5 ~ 7.5% for paraffin slurry, heat flux of 10 ~ 40 W/cm$^{2}$ for the simulated VLSI chips and Reynolds numbers of 5,300 ~ 15,900. The apparatus consisted of test section, paraffin slurry maker, pump, constant temperature baths, flowmeter, etc. The test section made of in-line, four-row array of 12 heat sources for simulating 4 * 3 multichip module which was flush mounted on the top wall of a horizontal rectangular channel with the aspect ratio of 0.2. The inlet temperature was 20 deg. C for all experiments. The size of paraffin slurry was constant as 10 ~ 40 .mu.m befor and after the experiment. The chip surface temperatures for paraffin slurry with the mass fraction of 7.5% showed lower by 16 deg. C than those for water when the heat flux is 40 W/cm$^{2}$. The local heat transfer coefficients for the paraffin slurry with the mass fraction of 7.5% were larger by 17 ~ 25% than those for water at the first and the fourth row. The local heat transfer coefficients reached to a row-number-independent, thermally fully developed value approximately after the third row. The local Nusselt numbers at the fourth row for paraffin slurry with the mass fraction of 7.5% were larger by 23 ~ 29% than those for water.

• Steel and Composite Structures
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• v.22 no.2
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• pp.449-472
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• 2016

This paper studies the seismic behavior of reinforced concrete (RC) walls with encased cold-formed and thin-walled (CFTW) steel truss, which can be used as an alternative to the conventional RC walls or steel reinforced concrete (SRC) composite walls for high-rise buildings in high seismic regions. Seven one-fourth scaled RC wall specimens with encased CFTW steel truss were designed, manufactured and tested to failure under reversed cyclic lateral load and constant axial load. The test parameters were the axial load ratio, configuration and volumetric steel ratio of encased web brace. The behaviors of the test specimens, including damage formation, failure mode, hysteretic curves, stiffness degradation, ductility and energy dissipation, were examined. Test results indicate that the encased web braces can effectively improve the ductility and energy dissipation capacity of RC walls. The steel angles are more suitable to be used as the web brace than the latticed batten plates in enhancing the ductility and energy dissipation. Higher axial load ratio is beneficial to lateral load capacity, but can result in reduced ductility and energy dissipation capacity. A volumetric ratio about 0.25% of encased web brace is believed cost-effective in ensuring satisfactory seismic performance of RC walls. The axial load ratio should not exceed the maximum level, about 0.20 for the nominal value or about 0.50 for the design value. Numerical analyses were performed to predict the backbone curves of the specimens and calculation formula from the Chinese Code for Design of Composite Structures was used to predict the maximum lateral load capacity. The comparison shows good agreement between the test and predicted results.

• Journal of Periodontal and Implant Science
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• v.43 no.6
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• pp.315-322
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• 2013

Purpose: In this study, we investigated the effect of silk scaffolds on one-wall periodontal intrabony defects. We conjugated nano-hydroxyapatite (nHA) onto a silk scaffold and then seeded periodontal ligament cells (PDLCs) or dental pulp cells (DPCs) onto the scaffold. Methods: Five dogs were used in this study. Bilateral 4 mm${\times}$2 mm (depth${\times}$mesiodistal width), one-wall intrabony periodontal defects were surgically created on the distal side of the mandibular second premolar and the mesial side of the mandibular fourth premolar. In each dog, four of the defects were separately and randomly assigned to the following groups: the PDLCcultured scaffold transplantation group (PDLC group), the DPC-cultured scaffold transplantation group (DPC group), the normal saline-soaked scaffold transplantation group, and the control group. The animals were euthanized following an 8-week healing interval for clinical, scanning electron microscopy (SEM), and histologic evaluations. Results: There was no sign of inflammation or other clinical signs of postoperative complications. The examination of cellseeded constructs by SEM provided visual confirmation of the favorable characteristics of nHA-coated silk scaffolds for tissue engineering. The scaffolds exhibited a firm connective porous structure in cross section, and after PDLCs and DPCs were seeded onto the scaffolds and cultured for 3 weeks, the attachment of well-spread cells and the formation of extracellular matrix (ECM) were observed. The histologic analysis revealed that a well-maintained grafted volume was present at all experimental sites for 8 weeks. Small amounts of inflammatory cells were seen within the scaffolds. The PDLC and DPC groups did not have remarkably different histologic appearances. Conclusions: These observations indicate that nHA-coated silk scaffolds can be considered to be potentially useful biomaterials for periodontal regeneration.

• Journal of Chest Surgery
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• v.12 no.3
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• pp.174-182
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• 1979

This is a report on four cases of successful surgical correction of coarctation of the aorta [COA] in Department of the Thoracic & Cardiovascular Surgery, Hanyang University Hospital. The first case was a postductal type of coarctation of the aorta associated with Patent ductus arteriosus [PDA], Persistent left superior vena cava [LSVC] and richly developed collateral circulation. Blood pressure was measured to be hypertensive at the arm, but hypotensive at the legs. The coarctation of the aorta was corrected with following procedure: Partial resection of the aortic wall with diaphragmatic structure lust above and below the coarctating line of the aorta, and then the defect of the aortic wall was closed by lateral aortographic suture. PDA was closed by ligation procedure. The second case a preductal type of coarctation of the aorta associated with PDA, LSVC, ventricular septal defect [VSD] and poorly developed collateral circulation. Normal blood pressure was measured at the arm, but hypotension was observed at the legs. Correction of coarctation of the aorta was performed under the establishment of tube bypass because of poor collateral circulation. After resection of coarctating short segment, end to end anastomosis was performed without any tension. PDA was closed by division procedure. Simple suture closure of VSD was performed by open heart surgery two weeks after correction of COA. The third case was a long segment COA without any other anomaly. Blood pressure was measured to be hypertensive at the arm, but hypotensive at the legs. Vascular prosthesis was performed using Teflon graft tube after resecting coarctating long segment [6.5 cm] of the aorta. The fourth case was a long segment COA associated with aortic insufficiency and richly developed collateral circulation. Normal blood pressure was measured at the arm, but hypotension was observed at the legs. Vascular prosthesis was performed using Teflon graft tube after resecting coarctating long segment [6.0 cm] of the aorta. Both blood pressure and peripheral pulse on the arm and the legs returned to normal postoperatively in all patients.

• Korean Institute of Interior Design Journal
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• v.25 no.2
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• pp.30-40
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• 2016

This study analyzed the attention concentration tendencies of one(1) subject who showed convergent exploratory acts actively through the gaze-brainwave measurement experiment of cafe space images and our research findings are as follows. First, the areas of interest (AOIs) that the subject gazed visually by paying attention to it and concentrating on it at a cafe space include counter&menu area, sign area, partition area, image wall area, stairs area, and movable furniture area, and built-in furniture area: seven areas in total. Second, conscious gaze frequency appeared the highest in counter&menu area, and conscious gaze appeared more later than in initial times. Third, conscious gaze pattern was divided into the zone that explored various areas dispersely (distributed exploratory zone) and the zone that explored between particular areas concentratedly (intensive exploratory zone). Fourth, as a result of analyzing the brainwave attention concentration, it was found that the attention concentration in prefrontal lobe (Fp1, Fp2) and frontal lobe (F3, F4) rose to a higher level in the zone of 15 to 16 seconds and this time zone was considered to be a zone where gazing at counter&menu area was very active. In addition, the attention concentration appeared higher in the initial zone than in the later zone, among the entire experimental time zones. Finally, as a result of analyzing the changes in activation by brain portion of the SMR wave expressed when maintaining the arousal and attention concentration, it was found that the right prefrontal lobe and the frontal lobe became activated in the time zone when the intensive exploration of "counter&menu area" and "movable furniture${\leftrightarrow}$built-in furniture area" had occurred and the time zone when the intensive exploration of "image wall${\leftrightarrow}$partition area" and "counter&menu${\leftrightarrow}$sign area" had occurred.