• KIEAE Journal
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• v.7 no.4
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• pp.51-56
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• 2007

This study focuses on developing natural ventilation system which is able to satisfy the good indoor air quality and air speed. The natural ventilation system developed in this study is for double window façade and it has two operation modes for summer and winter. Operational sections of the devices have been analyzed by CFD simulation to calculate discharge coefficients of openings and estimated indoor air speed. For the analysis of the appropriate installation area ratio for each room and the optimum installation area, TRNFLOW simulation has been used. As the results, we could see that the natural ventilation system can provide the similar pollutant removal performance to 0.7 ACH of mechanical ventilation with appropriate installation area and installation area ratio.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.04a
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• pp.69-74
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• 1998

Concrete has a many problems to apply high rise building of its low strength to weight and low ductility, compared to steel products. Therefore, it is necessary to make high strength concrete for applying to night rise building. In the experiment, the high strength concrete was made in variable of unit weight of binder, water to binder ratio(W/B), and sand to aggregate ratio(S/a) using batcher plant. As a result, it was possible to make high strength concrete using only materials for ordinary concrete without admixtures such like silica fume in batcher plant.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.4
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• pp.561-569
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• 2000

The purpose of this study is to construct a testing equipment with which several characteristics of the domestically developed swashplate type axial piston motor can be tested and to develop a software with which the data from experiment can be stored and can be applied. The results of the study are as follows; 1) The leakage flow and the torque of the motor being stopped is propotional to supply pressure and their relation can be showed by linear equations. 2) The motor movement is not smooth below 50 rpm but it moves smoothly up 170 rpm. 3) When the motor starts or stops, the pressure rise ratio effects decisively to the max. torque.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2005.03a
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• pp.195-202
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• 2005

High-rise residential buildings in these days tend to adopt a building frame system as primary earthquake resisting structural system for some architectural reasons. But there exist several ambiguities in designing such building frame systems according to current codes, with regards to : the effective stiffness property of RC cracked section in static and dynamic analyses, analytical model to evaluate story drift ratio and, deformation compatibility requirements of frames. The comparative study for these issues by appling IBC 2000 and KBC 2005 to a typical building frame system shows that demands of member strength and story drift ratio can be different significantly depending on designer's interpretation and application of code requirements.

• Korean Journal of Optics and Photonics
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• v.17 no.1
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• pp.23-30
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• 2006

Effects of liquid-crystal droplets size on electro-optical properties of the polymer dispersed liquid crystals are investigated experimentally The liquid crystal droplets size was varied by controlling the Laser power for phase separation and LC/oligomer composition ratio. Electro-optical switching voltage is dependent on the LC/oligomer composition ratio and liquid crystal droplet size. The experimental results showed droplet size will be small and saturation voltage is increased but rise time will be short at high power illumination laser light for phase separation.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1998.10a
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• pp.489-496
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• 1998

The single layer latticed domes have various behaviors with each geometrical shape and scale, and they are affected by vertical component as well as horizontal component of the dynamic load. And they represent ye different earthquake responses under each ground acceleration compared with another structural systems. Generally, all of the members of latticed domes undergo three dimensional deflections if they are subjected to arbitrary one dimensional horizontal load under earthquake motions. And their response characteristics are very different to their shapes, rise/span ratios, and damping mechanisms. In this study, the earthquake response behavior is verified according to the factor of each shape, rise/span ratio, and damping ratio of latticed domes, which undergo horizontal and vertical earthquake motions by numerical approaches.

• Journal of the Korean Institute of Rural Architecture
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• v.16 no.4
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• pp.59-66
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• 2014

This paper deals with vibration of plates with concentrated mass on elastic foundation. The object of investigating natural frequencies of tapered thick plate on pasternak foundation by means of finite element method and providing kinetic design data for mat of building structures. Free vibration analysis that tapered thick plate in this paper. Finite element analysis of rectangular plate is done by use of rectangular finite element with 8-nodes. In order to analysis plate which is supported on pasternak foundation. The Winkler parameter is varied with 10, $10^2$, $10^3$ and the shear foundation parameter is 5, 10. This paper is analyzed varying thickness by taper ratio. The taper ratio is applied as 0.0, 0.25, 0.5, 0.75, 1.0. And the Concentrated Mass is applied as P1, Pc, P2 respectively.

• Journal of Advanced Marine Engineering and Technology
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• v.24 no.4
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• pp.421-426
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• 2000

A study on the combustion and exhaust emissions characteristics of diesel engine with various suction air humidity is performed experimentally. In this paper, suction air humidity is changed from RH 50% to RH 90%, the experiments are performed at engine speed 1800rpm, and main measured parameters are cylinder pressure, fuel consumption rate, CO, HC, NOx and Soot emissions etc. Increase of suction air humidity from RH 50% to RH 90% does not effect specific fuel consumption, decreases maximum pressure in cylinder, ratio of maximum pressure rise and net heat release, and delays ignition timing. Also, that increases CO and HC emissions, decreases NOx emissions, but does not constant in changing tendency on emission.

• Journal of the Korean housing association
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• v.15 no.2
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• pp.55-62
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• 2004

Apartment design in residential Area is restricted by building distance limit code. Building distance limit decreases gradually to the 0.8H(height), and residential area has 250% site area ratio by building code, so site using has become efficient. In this study, examine the relationship between present building distance limit and right of daylighting environment by computer simulation. As well, high-rise residential officetel and multipurpose residential building becomes increase in commercial non-residential area. In the domestic, residential type multipurpose building made at the business area or central business area has 400∼800% site area ratio by building code. However, at a dweller's point of view, there are much lacks of environmental consideration to provide suitable daylighting environment. And, POE: Post Occupancy Evaluation is not completed yet. In this study, however, progress architectural environment prediction, basis by right of daylighting, and examine the possibility of daylighting by architectural distance limit code in residental area and by high-rise, high-density residential building in non-residental downtown area.

• Textile Coloration and Finishing
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• v.4 no.3
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• pp.91-96
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• 1992

The crystalline character of NaOH and KOH-cellulose complex having different tension ratio was studied using X-ray diffraction analysis. Cellulose crystalline lattices in tension alkali treatment cotton were identified by measuring and indexing the 101, 101, and 002 reflections. According as alkali treatment tension ratio increased on, cellulose gave rise to the formation of I rather than cellulose II. It seemed that a part of the fine structure of cellulose increased orientation with antiparaell and parallel chain crystal structure. The high tension ratio alkali treatment cotton resulted in lower dye sorption and in higher breaking strength and crease recovery.