• Journal of Korean Society of Steel Construction
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• v.18 no.2
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• pp.251-259
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• 2006

In some cases, wooden structures are used for medium-rise buildings. It is therefore necessary to develop and test a new structural system for medium-rise buildings using wooden structures. This study deals with high-performance, laminated, timber-based composite members, which consist of structural laminated timber and H-beam. Simple beam tests were performed to determine the strength, stress distributions, and failure patterns of laminated timber. The main parameters are the insertinglength (1, 1.5, and 2 times the H-beam height) and the epoxy between the top/bottom flange of the H-beam and the top/bottom flange of the laminated timber. The results of the test show that the specimen with an inserting length that is 2 times the H-beam height was characterized by fairly god strength and stiffness.

• Journal of Korean Society of Steel Construction
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• v.19 no.5
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• pp.493-501
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• 2007

Recently, in the domestic amount of materials,curtailment and economic efficiency security by purpose, tapered beam application is achieved, but the architectural design technology of today based on the material non-linear method does not consider solutions to problems such as brittle fracture. So, geometric non-linear evaluation thatincludes initial deformation, width-thickness ratio, web stiffener and unbraced length is required. Therefore, in this study, we used ANSYS, a proven finite elementanalysis program,and material and geometric non-linear analysis to study existing and completed tapered H-section as deep beam's analysis model. Main parameters include the width-thickness ratio of web, stiffener, and flange brace, with the experimental result obtained by main variable buckling and limit strength evaluation. We made certain that a large width-thickness ratio of the web decreases the buckling strength and short unbraced web significantly improves ductility.

• Resources Recycling
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• v.27 no.6
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• pp.30-37
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• 2018

A series of experiment was conducted to evaluate basic performances of low-pH, anti-washing grouts incorporating gypsum which applied for reinforcing underwater cavities in limestone- grounds. Various types of mix proportions were designed and the fluidity, strength and environmental impact of these mixtures were evaluated. The flowability was evaluated under two conditions, i.e., flows without and with pressing, respectively. Strength was measured for the hardened mixtures fabricated under conditions of air and water injections. The environmental impacts including the pH of the suspension and the suspended solids concentration for the mixtures were evaluated. The low pH of fresh mixture suspension, below than 10, was achieved by incorporation of gypsum. The mix proportions of cement-quartz powder-gypsum binders and chemical agents resulted in mortar natural flow 7-10 cm and uniaxial compressive strength 4 MPa were derived.

• Journal of Oral Medicine and Pain
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• v.30 no.1
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• pp.15-23
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• 2005

Mucin glycoproteins are the primary carriers of the oligosaccharide moieties that constitute the blood group substances in human saliva. The aim of this study was to determine whether or not the conversion of either the A or B blood group antigens to the H antigen can occur during the degradation process of stored saliva samples. Forty subjects (20 subjects in each A and B blood group) identified as secretors were enrolled in this study. Fresh whole saliva samples and their clarified supernatants were stored at room temperature for 1 week. The conversion of the blood group antigens was detected by SDS-PAGE and immunoblotting. Among the subjects showing the conversion in whole saliva, glandular saliva samples were obtained from 8 subjects (4 subjects in each A and B blood group). Submandibular-sublingual saliva (SMSL) and a mixture of SMSL and parotid saliva (PS) were stored at room temperature for 1 week. The conversion of the blood group antigens was detected by the same method. The obtained results were as follows: 1. In the clarified samples of whole saliva, the A antigen was detected as being either intact (5%) or degraded molecules (95%) after the 1 week period. Conversion of the A antigen to the H antigen was detected in 5 subjects (25%). In the unclarified samples, the A antigen was either detected as degraded molecules (90%) or was not detected (10%). Conversion of the antigen had occurred in 4 subjects (20%). 2. In the clarified samples of whole saliva, the B antigen was detected as intact (20%) or as degraded molecules (65%) or was not detected (15%) after the 1 week period. Conversion of the B antigen to the H antigen was detected in 7 subjects (35%). In the unclarified samples, the B antigen was detected as intact (5%) or as degraded molecules (65%), or was not detected (30%). Conversion of the antigen was observed in 2 subjects (10%). 3. In the glandular saliva samples, only one of the four subjects displayed an antigenic conversion from the A to H antigen or from the B to H antigen. The conversion had occurred in both the SMSL samples and the SMSL and PS mixture. No degradation of the antigens was detected in the other three samples of the A or B blood groups, nor was there any conversion. The results demonstrated that conversion of the blood group antigens could occur in saliva, and suggested that the enzymes responsible for the conversion are present in saliva. Further studies on the origin and activity of the specific glycosidases in saliva as well as quantitative measurements of the antigenic conversion will be needed.

• Computational Structural Engineering
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• v.6 no.3
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• pp.125-137
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• 1993

Recently, many researches are being dealt with the adaptive method for improving the accuracy of finite element solution. This paper deals with rh-methods that are the combination of r and h-method ; r-method is to relocate the nodes for the grid optimization, h-method is to divide the elements with great error into the equal shape. As a results, rh-method has the same error decrease and convergence as h-method in the same degree of freedom, but it has more exact result of finite element in the state of restraining degrees of freedom than h-method alone.

• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.437-440
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• 2007

Design equations for calculating the lateral-torsional buckling moment resistances of I-section beams with continuous lateral top-flange bracing subjected to several loading conditions are investigated based on elastic finite-element analyses. The equations presented in this study are compared with current moment gradient modifiers presented by other researchers and specifications. The equation suggested in the SSRC Guides(1998) has a good agreement with the results of finite-element analyses. The moment gradient correction factors proposed in the SSRC Guides(1998) should be easily used to calculate the lateral-torsional buckling moment resistance of I-beams with continuous lateral top-flange bracing.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.6
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• pp.1060-1068
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• 2002

Compound continuously variable transmission(CVT) mechanisms are proposed, which can offer a backward mode, a geared neutral, an underdrive mode and an overdrive mode. They are composed of a 2K-H I type differential gear unit, a V-belt type continuously variable unit(CVU), a few friction clutches and gears, and not required of a starting device as a torque converter. Compound CVT mechanisms developed here present two distinct operating modes which are a power circulation mode and a power split mode. The transition of two modes takes place at the particular CVU speed ratio. For these CVT mechanisms, performance analysis related to speed ratio, power ratio and efficiency are executed and proven by experimental studies.

• Journal of Ocean Engineering and Technology
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• v.15 no.4
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• pp.86-91
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• 2001

In lateral ground flow, slope stability, and land slide problems, H-piles have been often used for a horizontally deforming ground to prevent the failure of mass of soil in a downward and outward movement of a slope. Here, Theoretical equations are derived to estimate the lateral force, assuming that the Mohr-coulomb's Plastic states occures in the ground just around H-piles. In this study, the mechanism of lateral force acting on passive pile that is in a row, situated in the ground undergoing plastic deformation was discussed, and its theoretical analysis was carried out considering the interval between H-piles. The solution of the theoretical equation derived from here showed resonable characteristic for constants of soil as well as for the interval, widths, and heights of H-pile.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.10
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• pp.1835-1840
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• 2008

In this paper, a dual band H-shaped microstrip patch antenna is designed for RFID application. Using shorting pin and H shaped for dual resonators and control dual frequency independently. The antenna shows a good performance at the frequency, 912MHz and 2.45GHz for the radiation characteristic and input impedance matching, as well. The reflection is lower than -10dB and a good directivity higher than 3dB is achieved for both frequency.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.3
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• pp.200-207
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• 2000

The analysis of interference and efficiency are important phases in the design of planetary gear train. Because most planetary gear trains contain internal gear called ring gear, interferences between ring gear and planet gear should be analyzed in the step of design and manufacturing. Addendum modification coefficient, pressure angle, speed ratio between ring gear and sun gear are governing factors for interferences. In this paper, the interferences of 2K-H I type planetary gear train based on various planetary gear trains are studied. As that results, the ranges of addendum modification coefficients which would not lead to interferences is analyzed. Based on these ranges, theoretical efficiencies are investigated as 6 configurations of 2K-H I type planetary gear train, which is based on basic efficiency, and optimal addendum modification coefficients which generate the maximum efficiency of planetary gear train are presented. To prove results of theoretical efficiency analysis, experimentations are performed.