• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.721-728
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• 2008

Top-Base Method is a stabilization method for light weight structures particularly in the soft ground. It is widely used for the increment of bearing capacity and the effect of restraining settlement when the bearing capacity of the ground is not enough. Top-shaped cone concrete foundations are installed in graveled laid over soft ground. The principle of the basic method is to maximize effect of dispersing the overburden pressure by increasing the contact area of the top-shaped cone. Therefore, the bearing capacity is increased and the settlement is decreased by the embedded resistance of pile part in the ground. In this paper, the plate bearing test was conducted to evaluate the feasibility of Top-Base foundation. Based on the test results, the coefficient of subgrade reaction, elastic modulus, and settlement of foundation on reclaimed land was derived.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.6
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• pp.101-109
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• 2019

The purpose of this study is to improve a general Top-Down construction process for superstructure construction period reduction. In a general Top-Down construction sequence, the ground floor slab is set up first. Subsequently, 1st basement level construction including core walls is constructed. Initiation of the ground level superstructure gets waited until then. In this study, removable deck plate installation on the bottom of the core walls of ground level is preceding the concrete casting, therefore, ground level superstructure construction is able to get started earlier. Up to first typical floor concrete casting, total of seventy-two working(calendar) days will be resulted in a reduction from the total construction periods.

• Journal of the Korean Wood Science and Technology
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• v.37 no.3
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• pp.192-199
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• 2009

This study was carried out to investigate the performance of a radio-frequency/vacuum dryer combined with a mechanical compressive load (RF/VC) with a scale of about $3m^3$ during drying board of Azobe (Lophira alata) and Korean red pine (Pinus densiflora). The degree of vacuum of the RF/VC system was maintained at 80~105 torr, and wood temperature was increased from $40^{\circ}C$ at the beginning of drying to $60^{\circ}C$ at the end of drying and the radiofrequency generator was operated with schedule of 7 minute-ON and 3 minute-OFF. The wood temperatures near charge plate always remained higher than those of the control during all of the drying stage, whereas the wood temperature near ground plate always remained lower than those of the controlled. As drying time proceeding, the temperature of the wood near ground plate presented lower than those of the control. Whereas the temperature of the wood near charge plate presented higher than those of the controlled. The final average moisture contents of the Azobe boards stacked near the input side of the RF generator showed slightly lower than those near the opposite side. Those of the wood stacked in the layers near the charge plate were lower than those of near the ground plate. The average length of surface checks of the Azobe boards stacked near the charge plate was very slight, whereas that toward the ground plate represented high values. The efficiency of input energy was simliar with the commercial systems.

• Journal of the Korean Geosynthetics Society
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• v.15 no.1
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• pp.37-46
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• 2016

Rotary pile consists a single or multiple helix plate and it is installed into the ground using the rotation of the helix plate. Rotary pile in soft ground is able to be supported by pile shaft and helix plate. When the pile is installed into hard layer relatively, the end bearing capacity is possible to be increased by the lower helix plate. In this paper, small-size rotary piles were manufactured with using steel pipe which is reduced to 1/5 size of the rotary pile on the construction field. Pile load test was carried out on the foundation soil which was formed by weathered soft soil. The bearing capacity of small-scale piles depends on the number of helix plate, the length of plate diameter, and an interval of plates, respectively. The bearing capacity of pile increases about 40% with 3 helix plate and it is also confirmed that the bearing capacity is improved about 10% as the increment of plate interval.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.7
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• pp.976-983
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• 2000

The flow characteristics around an elliptic cylinder with axis ratio of AR=2 located near a flat plate were investigated experimentally to study the interaction between the cylinder wake and the turbulent boundary layer. The pressure distributions on the cylinder surface and on the flat plate were measured with varying the angle of attack of the cylinder. In addition, the velocity profiles of wake behind the cylinder were measured using a hot-wire anemometry As the angle of attack increases, the location of peak pressure on the windward and leeward surfaces of the cylinder moves toward the rear and front of the cylinder, respectively. At positive angles of attack, the position of the minimum pressure on the flat plate surface is moved downstream, but it is moved upstream at negative angles of attack. With increasing the angle of attack, the vortex shedding frequency is gradually decreased and the critical angle of attack exists in terms of the gap ratio. By installing the elliptic cylinder at negative angle of attack, the turbulent boundary layer over the flat plate is disturbed more than that at positive incidence. This may be attributed to the shift of separation point on the lower surface of the cylinder due to the presence of a ground plate nearby.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.12 s.354
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• pp.75-82
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• 2006

In this paper, we design the meander line inductors with high sensitivity and high quality factor(Q) using high characteristic impedance of aperture ground plate. Sensitivity as a frequency is new defined by variation of effective inductance per analysis frequency range instead of self resonance frequency (SRF). An equivalent lumped circuit is derived to explain the characteristic of high frequency inductor. The 4 nH meander line inductor with aperture ground plate has 0.45 nH/GHz of good sensitivity and 86 of Q at 0.7 GHz.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.9
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• pp.443-448
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• 2006

Non-contacting capacitive sensor based on Thompson-Lampard theorem have been fabricated and characterized for measuring of 때 order displacements. To overcome disadvantages of the existed capacitive sensors of parallel plate type with 2-electrodes and 3-electrodes, the developed new sensor was designed to have 4-electrodes with a constant gap of 0.2mm between the electrodes. Two of the electrodes were used as a high potential electrode and a low one, the other two electrodes were used as guard electrodes. These electrodes were made from copper using RF sputtering system on a sapphire plate with diameter 17 mm and thickness 0.7 mm. This sensor can be used for measuring the distance not only between the sensor and metallic target connected to ground potential but also non-metallic target without ground connection.

• Journal of Electrical Engineering and Technology
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• v.6 no.3
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• pp.402-407
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• 2011

The current paper describes a simpler ground-type, single-plate electrowetting configuration for droplet transport in digital microfluidics without performance degradation. The simplified fabrication process is achieved with two photolithography steps. The first step simultaneously patterns both a control electrode array and a reference electrode on a substrate. The second step patterns a dielectric layer at the top to expose the reference electrode for grounding the liquid droplet. In the experiment, a $5{\mu}m$ thick photo-imageable polyimide, with a 3.3 dielectric constant, is used as the dielectric layer. A 10 nm Teflon-AF is coated to obtain a hydrophobic surface with a high water advancing angle of $116^{\circ}$ and a small contact angle hysteresis of $5^{\circ}$. The droplet movement of 1 mM methylene blue on this simplified device is successfully demonstrated at control voltages above the required 45 V to overcome the contact angle hysteresis.

• Journal of the Korean Society for Railway
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• v.3 no.2
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• pp.84-91
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• 2000

The general concept of reinforced roadbed in the high-speed railway is to cope with the soft ground for the bearing capacity and settlement of foundation soil. The cyclic plate load tests were performed to determine the behavior of reinforced ground with multiple layers of geogrid underlying by soft soil. With the test results, the bearing capacity ratio, elastic rebound ratio, subgrade modulus and the strain of geogrids under loading were investigated. Based on these plate load tests, laboratory model tests under cyclic loading were conducted to estimate the effect of geogrid reinforcement in particular for the high-speed rail roadbed. The permanent settlement and the behavior of earth pressure in reinforced roadbed subjected to a combination of static and dynamic loading are presented.

• Journal of Korean Tunnelling and Underground Space Association
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• v.5 no.3
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• pp.217-226
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• 2003

This study is focused on the finding out load transfer mechanism in the ground near the tunnel during tunnel excavation in the jointed sandy ground. Laboratory model tests were performed on various cases of the overburden heights above tunnel crown, location, and degree of discontinuity planes. For model tests, a movable plate was installed in the midst of the bottom of sandy ground. This plate, moving downwards, was intended to model the stress relaxation during tunnel excavation. The load transfer was measured at the fixed separated bottom plates adjacent to the movable plate. As the result, the loosening zone and the load-transfer form around the tunnelling site were affected by the overburden height and the characteristics of discontinuous planes. And large loosening zone was developed along the discontinuous planes which were close to the tunnel.