• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2757-2762
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• 2007

A cyclone design concept named Convex cyclone was developed to reduce pressure losses. Contrary to conventional cylinder-on-con type cyclone, inner wall of Convex cyclone are defined with a continuous curve and it has convex shape body. The discontinuity of inner diameter variation rate of cylinder-on-con type cyclone cause additional pressure loss. Continuous wall of Convex cyclone prevent additional pressure loss. In order to verify Convex cyclone design concept, we make a comparative experiments between Stairmand HE and Convex cyclone. Experimental Convex cyclone designed based on Stairmand HE model, and inner wall are defined with circular arch. The experimental result clearly shows that Convex cyclone can achieve maximum 50% pressure loss reduction with a few percent of collection efficiency drop. In addition, the experimental results indicated the existence of optimum convexity, minimum pressure loss, of cyclone wall.

• Journal of Korean Association for Spatial Structures
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• v.14 no.1
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• pp.51-59
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• 2014

Single layer free-form structures are being highlighted in the field of architecture due to its attractive shape. In these structures, node connecting system is very important because the node must resist bending and axial stress simultaneously. So the local and global stabilities of entire structure can be determined by the stiffness of node system. In this study, therefore, various types of bending test with axial force were performed. As a result, bending capacity with axial force of a new spherical node for free-form structure could be performed and structural capacities were checked to use in real structure.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.3 no.1
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• pp.44-50
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• 1995

Abutment dies which resemble the actual size and shape of crown abutment is essential in most of the research area of fixed prosthodontics like marginal accuracy, crown seating, behavior of luting agent and so on. Seeing the large portion of research is done with round shaped dies in different size and cone angles, the necessity of research on the crown abutment is self-evident. 500 molar abutments were collected randomly through the commercial dental laboratoy, regrdless of their position in the dental arch, sex, and age. The measurements of 22 points of a die were done, and the results were as fogbows : 1. The height of the molar dies was $3.9{\pm}1.2mm$ 2. The bucco-lingual width was $8.9{\pm}1.2mm$ at the base, and $7.4{\pm}1.2mm$ at the occlusal. 3. The desio-sistal width was $8.2{\pm}1.2mm$ at the base, and $7.0{\pm}1.3mm$ at the occlusal.

• Journal of The Korean Digital Architecture Interior Association
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• v.12 no.1
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• pp.5-13
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• 2012

The frame of pipe greenhouses in Korea have been collapsed increasingly due to very weak in structure caused by the heavy snow and strong wind. In order to reduce the collapse of green houses, it is urgent to develop the new structural system in stress tolerant greenhouses. Therefore, this paper performed the structural analysis of greenhouse frame in accordance with snow loads and wind loads. Three type models in structural frame configuration of greenhouses, that is, existing type, diagrid type, and honeycomb type are selected. It was classfied the section shape of structural frames in greenhouses into arch style, standard style, and diagonal standard style. As a result of this paper, it was verified that the structural system of diagrid type is better than that of existing type against snow loads and wind loads in the frame of greenhouses.

• Journal of Ship and Ocean Technology
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• v.1 no.1
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• pp.15-25
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• 1997

A series of towing tank tests were carried out for 18 full ship models of high block coefficients. The resistance coefficients and wake distribution at the propeller plane were measured and carefully examined. Regression analysis was employed to find out the relationships with the hull form parameters. Equations for wave resistance coefficient, form factor, and nominal wake are given. A harmonic analysis of measured wake was performed to look into the influence of the local stern shape on the magnitude of fluctuating wake components at three different radii. The amplitude of wake harmonics was also expressed by regression quations. It was found that the regression formulas were very useful in estimating resistance and circumferential wake characteristics of full ship models. It was also considered that the formulas presented in this paper could be utilized in the hull form improvement in a preliminary design.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.169-170
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• 2009

CFT structure has many advantages compared with the ordinary structural member made of steel or reinforced concrete. Because of increases in ductility, stiffness and load carrying capacity of overall structure owing to confinement effect of steel box and concrete, CFT structure is widely used to columns. Recently, the utilization of CFT member has been expanded to bridge structure as a girder member. The purpose of this study is to develop the analytical model and propose design method for CFTA girder bridge consisting of CFT structure, arch shape and tendons.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.167-168
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• 2009

The CFT structure is applied to newly developed CFTA girder because of improvement of ductility deformation, stiffness and internal force of structure owing to the interaction between steel tube and core concrete. CFTA girder is the structure which can reduce tensile stress due to external loads by using its arch shape and prestress force. This paper proposed constructional stage procedure and represented analytical technique considering constructional stage to investigate the safety against bridge collapse on construction and on operation.

• Journal of the Korean Institute of Rural Architecture
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• v.12 no.3
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• pp.27-34
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• 2010

Unbraced vinyl house frame that is economically installed is certainly easy to collapse under the influence of excess snow load. To make it more cheaply in putting up as well as more efficiently in withstanding the applied snow load, it is essential to insert additional bracing into the existing unbraced vinyl house frame. On the other hand, there are varieties of possible bracing shapes that can be formed. However, their efficiencies are different. Therefore, it is important to identify the most effective bracing shape. In this study, 2 different kinds of bracing shapes, horizontal and inclined bracing, are used to additionally install in the ordinary single frames in order to show the effect of the bracing resisting the applied snow load and compare the bending moment, axial force, combined stress and vertical displacement of the vinyl house frame.

• The Journal of the Korean dental association
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• v.16 no.1 s.104
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• pp.37-42
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• 1978

A study on the impacted teeth of the anterior segment was carried out. The data for this study were compiled form 1739 outpatients of the Department of Orthodontics, College of Dentistry, Seoul National University. The following conclusions were obtained; 1. The frequency of the impacted teeth of the anterior segment was 2.8% and the frequency of male was 4.0%, that of female was 2.1%., respectively. 2. The order of occurrence of the impacted teeth in the anterior segment was maxillary canine mesiodens, maxillary central incisor, maxillary lateral incisor, mandibular canine. 3. The etiologic factors of the impaction were the space deficiency for eruption, cleft palate, the prolonged retention of deciduous teeth, dentigerous cyst. 4. The favorable results of treatment and prognosis were obtained from the impacted teeth of the normal shape after surgical exposure and adhered the plastic attachment and inducted them into the dental arch.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.394.2-394
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• 2002

The differential equations governing free vibrations of the elastic arches with unsymmetric axis are derived in the rectangular coordinates rather than in polar coordinates, in which the effect of rotatory inertia is included. Frequencies and mode shapes are computed numerically for parabolic arches with both clamped ends and both hinged ends. Comparisons of natural frequencies between this study and SAP 2000 are made to validate theories and numerical methods developed herein. (omitted)