• International Journal of Precision Engineering and Manufacturing
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• v.4 no.3
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• pp.20-27
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• 2003

Compensation of probe radius is required for accurate measurement in metal working industry. Compensation involves correctly measuring data on the surface in the amount of radius of the touch probe with a Coordinate Measuring Machine (CMM). Mechanical parts with free-formed curves and surfaces are complex enough so that accurate measurement and compensation are indispensable. This paper presents necessary algorithms involved in the compensation of the probe radius for free-formed curves and surfaces. Application of pillar curve is the focus for the compensation.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.10
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• pp.613-617
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• 2014

This paper was analyzed electrical characteristics of super junction power MOSFET considering to charge imbalance. We extracted optimal design and process parameter at -15% of charge imbalance. Considering extracted design and process parameters, we fabricated super junction MOSFET and analyzed electrical characteristics. We obtained 600~650 V breakdown voltage, $224{\sim}240m{\Omega}$ on resistance. This paper was showed superior on resistance of super junction MOSFET. We can use for automobile industry.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.4
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• pp.68-78
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• 2003

Recently, low speed vehicle (LSV) is beginning to appear for various usages. The body of the LSV is usually made of the aluminum space frame (ASF) type rather than the monocoque or unitary construction type. A pa.1 of the reason is that it is easier to reduce mass efficiently while the required stiffness and strength are maintained. A design flow for LSV is proposed. Design specifications for structural performances of LSV do not exist yet. Therefore, they are defined through a comparative study with general passenger automobiles. An optimization problem is formulated by the defined specifications. At first, one pillar which has an important role in structural performances is selected and the reinforcements of the pillar are determined from topology optimization to maximize the stiffness. At second, the thicknesses of cross sections are determined to minimize the mass of the body while design specifications are satisfied. The optimum solution is compared with an existing design. The optimization process has been performed using a commercial optimization software system, GENESIS 7.0.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.941-942
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• 2013

• 한국지구물리탐사학회:학술대회논문집
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• 2008.10a
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• pp.131-136
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• 2008

We performed a non-destructive geophysical survey such as an elastic wave survey, electric specific resistance survey, plate loading test, etc. in order to grasp the structure and status of the ground around the pillar gate and to provide the directions and design data for preservation and maintenance during reconstruction. The result of electric specific resistance survey shows 50-1300 ohm-m range of general electric specific resistance distribution. Besides, the positions around 1m south of stone pillars, between stone pillar No.3 and 4, and 1m north of stone pillar No.2 and 3 show abnormality of relatively lower electric specific resistance than their surroundings. The abnormality of low electric specific resistance appearing between stone pillar No.3 and 4 shows consistency with the abnormal section appearing from the result of elastic wave reflection survey. The result of a plate loading test shows that allowable bearing force is over $10.70tf/m^2$, and the settlement amount at this time was calculated as 19.635mm. The design load during reconstruction of pillar gates was calculated as $16.37t/m^2$ by applying assumption values, which is far more than the allowable bearing force, so it is judged that a measure to strengthen the foundation ground is necessary.

• Journal of the Korean Geosynthetics Society
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• v.21 no.4
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• pp.21-29
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• 2022

The room-and-pillar method or grid-type underground space is a method of forming a space by excavating the excavation part at regular intervals so that it is orthogonal and using natural rock mass as a structure. Such excavation may appear different in size from the excavation stage where the maximum displacement occurs depending on the excavation direction and sequence. In this study, considering the installation of support materials such as shotcrete and rock bolts for the optimal design of the excavation process, the safety and constructability of the design and construction of the grid-type underground space under specific ground conditions were analytically reviewed. The ground conditions were set using an numerical method, and the stress at pillar and displacement at center of room were considered for each excavation stage and construction type under a constant surcharge. The height of the space was 8m, which was set higher than the size of a general office, and was reviewed in consideration of equipment and plant facilities. In addition, the degree of displacement control according to the installation of support materials was reviewed in consideration of shotcrete and rock bolts.

• Journal of the Korean Society of Safety
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• v.28 no.4
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• pp.107-113
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• 2013

The design of rainwater storage system unit to manufacture its reservoir tank was tried, the simulation to predict of their structural strength was carried out. Rainwater storage system unit should be easy to their machinability, transport and assemble. Especially, their structure was able to secure the water storage space, withstand loads and easily response to pollution. Considering these various requirements, they have to Doria-pillar structure of the Roman architectural style because these designs could disperse the loads which are applied to them. Therefore, the six kinds of models possible were proposed. Several boundary conditions were given to each model. Their structural strength was predicted through the simulation on their stress and the displacement distribution to constant load. From the evaluated data, the structure which has a large pillar in the central of unit and four small pillars each corner was the best.

• Journal of the Semiconductor & Display Technology
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• v.13 no.3
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• pp.45-50
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• 2014

In this paper, we propose a super-junction MOSFET (SJ MOSFET) fabricated through a simple pillar forming process by varying the Si epilayer thickness and doping concentration of pillars using SILVACO TCAD simulation. The design of the SJ MOSFET structure is presented, and the doping concentration of pillar, breakdown voltage ($V_{BR}$) and drain current are analyzed. The device performance of conventional Si planar metal-oxide semiconductor field-effect transistor(MOSFET), Si SJ MOSFET, and SiGe SJ MOSFET was investigated. The p- and n-pillars in Si SJ MOSFET suppressed the punch-through effect caused by drain bias. This lead to the higher $V_{BR}$ and reduced on resistance of Si SJ MOSFET. An increase in the thickness of Si epilayer and decrease in the former is most effective than the latter. The implementation of SiGe epilayer to SJ MOSFET resulted in the improvement of $V_{BR}$ as well as drain current in saturation region, when compared to Si SJ MOSFET. Such a superior device performance of SiGe SJ MOSFET could be associated with smaller bandgap of SiGe which facilitated the drift of carriers through lower built-in potential barrier.

• Journal of the Korean Geotechnical Society
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• v.23 no.11
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• pp.5-14
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• 2007

In this study, Matsuda formula used to evaluate the loads acting on the pillar was investigated and load reduction factor(${\alpha}$) was evaluated by numerical analysis to better apply for the design. From the results, normal stress was concentrated to one side due to excavation of preceding tunnel after construction of pillar. And 86.5% of maximum normal stress was revealed partly unequally when the ground was poor. By numerical analysis, $14{\sim}83%$ of total loads calculated by Matsuda formula decreased and then, from these results, load reduction factor(${\alpha}$) was estimated. From now on, stability and economic aspects could be guaranteed by applying the load reduction factor(${\alpha}$).

• Journal of the Korean GEO-environmental Society
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• v.15 no.1
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• pp.53-62
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• 2014

In Korea, in general, separation distance between existing parallel tunnels was set at two to five times as distant as the diameter of the tunnels according to ground conditions. Recently, however, actual applicability of closely spaced parallel tunnels whose distance between tunnel centers was shorter than the diameter has increased due to environmental damages resulting from massive cutting, restriction in purchase of required land, and maintenance of linear continuity. In particular, when the pillar width of tunnel decreases, the safety of pillars affects behaviors of the tunnel and therefore the need for diverse relevant studies has emerged. However, research so far has been largely confined to analysis of behavior characteristics of pillars, or parameters affecting design, and actually applicable and quantitative data have not been presented. Accordingly, in order to present a stability evaluation method which may maximally reflect construction conditions of spots, this study reflected topographical and stratigraphic characteristics of the portal part with the highest closeness between the tunnels, simulated multi-layer conditions with rock mass and complete weathering, and assessed the degree of effect the stability of pillars had on the entire tunnels through numerical analysis according to changes in pillar width by ground strength. This study also presented composite analysis result on ground surface settlement rates, interference volume rates, and average strength to stress and a formula, which may be applicable to actual work, to evaluate safety rates of closely spaced parallel tunnel pillars and minimum pillar width by ground strength based on failure criteria by Hoek-Brown (1980).