• Proceedings of the Materials Research Society of Korea Conference
• /
• 1994.05a
• /
• pp.165-166
• /
• 1994

The depth profiles of the as-grown and the annealed NH$_3$ oxide film in NH$_3$(7.5%)/$N_2$ ambient at 45$0^{\circ}C$ are analized . This annealing in the ambient of mixed gases removes the small quantities of N component from the NH$_3$ oxide film. In AES analysis, the NH$_3$ oxidation shows the exact stoichiometry of SiO$_2$ and a sharp slop at SiO$_2$/Si interface.

• Journal of Energy Engineering
• /
• v.29 no.3
• /
• pp.25-33
• /
• 2020

In this study, flow and structural computational analysis were performed to investigate the structural safety of the lightweight butterfly valve disc designed by topology optimization. After flow analysis, as the opening angle increased, the flow coefficient increased non-linearly and showed a gentle slop. When the opening angle was 12 degree, the cavitation could be predicted. After FE analysis, all FE von-Misses stresses of the lightweight disc were smaller than the yield strength of the material, and all FE maximum deformations were also smaller than the conservative deformation of the previous study. Ultimately, it was confirmed that the structural safety of the lightweight valve disc based on computational analysis is effective.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2005.03a
• /
• pp.831-837
• /
• 2005

In this study, a computer program to predict the behavior of laterally loaded single pile and pile groups was developed by using a beam-column analysis in which the soils are modeled as nonlinear springs by a family of p-y curves for subgrade modulus. The special attention was given to the lateral displacement of a single pile and pile groups due to the soil condition and the cap rigidity. The analysis considering group effect was carried out for $2\;{\times}\;2\;and\;3\;{\times}\;3$ pile groups with the pile spacing 3.0B, 4.0B and 5.0B. Based on the results obtained, it is found that the overall distributions of deflection, slope, moment, and shear force in a single pile give a reasonable results irrespective of cap connectivity conditions. It is also found that even though there are some deviations in deflection prediction compared with the observed ones, the prediction by present analysis simulates much better the general trend observed by the centrifuge tests than the numerical solution predicted by PIGLET.

• Journal of the Korean Society of Safety
• /
• v.24 no.2
• /
• pp.48-54
• /
• 2009

Structures to support against slop failures or resist earth pressure like masonry retaining walls or retaining walls have continued to advance and evolve to new eco-friendly, easy-to-construct, crib retaining walls with varied forms and construction methods, meeting the needs of the times. Researches until now, however, have focused on the analyses of site displacement or stability of the whole site including structures like retaining walls, and thus, researches on rational design or method for stability analysis are lacking. Therefore, this study was conducted on a number of stability analyses, such as the visual power line or stability on sliding, being presented for bin walls, which enable vegetation to grow and were developed and applied in varied forms, meeting the development demands for eco-friendly retaining wall structures. This study compared the results of stability analyses, determined their feasibility, and evaluated their stability according to the height and facade slope of retaining walls. According to the results of this study, traditional masonry retaining wall analysis showed rather conservative stability evaluation results in the stability evaluation of bin walls, and the method using the visual power line seems to be objective because it produced similar results to the stability evaluation method on sliding or turnover.

• Journal of Korean Society of Water and Wastewater
• /
• v.12 no.3
• /
• pp.81-90
• /
• 1998

The purpose of this study was to analyze the effect of the groin which was constructed in the down stream of urban river for the prevention of sedimentation on the improvement of the water quality. We studied on the groin in the downstream of Taehwa River constructed to keep the navigation depth of Ulsan day, and used the measured data of the water quality and river discharge. In order to analyze the charge of the water quality due to the groin Que12E model was applied, and BOD and DO was examined. The analysis showed that removal of the groin would not have significant effect on the improvement of the water quality, rather, interception of the pollution source coming into the upstream of the groin would be more influential on the improvement of the water quality. Therefore, It was concluded that to improve the water quality in mild bottom slop of tidal river, interception of the pollution source and river maintenance discharge should precede.

• Proceedings of the KSR Conference
• /
• 2000.11a
• /
• pp.295-302
• /
• 2000

Slab guideway, surface treatment, heat line installation, and joint connection for Automated Guideway Transit with rubber tire are researched. While the AGT with rubber tire is constructed in city, the precast slab guideway must be considered a reduction of the construction period and the noise under construction. which related with environment. To do that, a basic design and the structural analysis for the precast slab guideway with rubber tire are studied. The surface treatment and the heat line installation of that are also compared with currently used methods. Tining method is applied to the surface treatment adopted from the concrete pavement application currently in use. The connection method between the slab of bridge and precast guideway are suggested with a bolt type and a bond type. To minimize noise and vibration of the connection while the AGT is in driving, the slop connection method can be enhanced the serviceability.

• Journal of Sensor Science and Technology
• /
• v.18 no.6
• /
• pp.449-455
• /
• 2009

In this paper, we developed a digital gait analyzer using the triaxial accelerometer(TA). An approach for normal gait detection employing decay slope peak detection(DSPD) algorithm was presented. The TA was attached to the center of the waist of a subject. The subject walked a bare floor at 60, 92 and 120 steps/minute. We analyzed vertical axis acceleration signal for gait detection. At 60, 92, 120 steps/minute walking, detection accuracy of gait events were over 99 % accuracy.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 1999.10c
• /
• pp.499-505
• /
• 1999

The time paramters most frequently used in hydrology are the tuime of concentration, lag time , time base, time to equilibrium , time to peak, time of travel, and residence time. Especially the time of concentraion constitute an important part of operating rainfall-runoff modeling and determining critical rainfall intensity. In the result of simulation , we discoved that SCS foumula has the highest value with length, Kerby with height and SCS with slop respectively, while only Kraven formula has the lowest value in them. With concerning to relative sensitivty, the time of concentraion was marked the constant effect according to increase of length and slope level, and the length has much more effect than the slope relatively in parameters.

• Bulletin of the Society of Naval Architects of Korea
• /
• v.22 no.4
• /
• pp.17-27
• /
• 1985

In this paper, an approximate calculation method on the transverse strength of oil tankers by use of slop-deflection method os described which considers the effect of shear deflection and varing section in elements and the result of calculation in models and actual ships, is presented. The object of this paper is focused on the development of program which can be used widely regardless strut numbers in transverse frame rings. To examine the reliability of the above method, the results in this paper are compared with the results which are obtained by use of SAP4(Structure Analysis Program) based on finite element method. The application of the Slope-Deflection Method on the transverse strength of oil tankers has the advantage that this method takes less than the other methods in calculation.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2005.03a
• /
• pp.232-239
• /
• 2005

Recently geosynthetics that can be constructed on soft ground have been used for reinforcement and separation in various ways. Through laboratory model tests and numerical analysis, in this study, estimated the suitability of cable elements and appropriate input factors considering loading effect in modeling of geosynthetics. First, in laboratory model tests, geosynthetics were constructed on the clay, and covered with the thickness, 7.5cm of sand mat. And then static and dynamic model tests were performed measuring loading, settlement, ground lateral displacement, and displacements of geosynthetics, but, for cyclic loading, bearing capacity increased linearly with stiff slop because cyclic loading with constant cyclic pressure compacted the ground. Numerical analysis were performed with FLAC 4.0 2D using Mohr-Coulomb and Modified Cam-Clay models, and they compared with the results of model tests. Cable elements of FLAC in modeling geosynthetics couldn't consider the characteristics of geosynthetics that increase shear strength between geosynthetics and clay according to the loading increase. Therefore, in this study, appropriate equation that can consider loading effects in Cable elements was proposed by Case Study.