• Proceedings of the KSME Conference
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• 2000.04b
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• pp.119-124
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• 2000

The heat transfer characteristics of confined turbulent slot jet impingement on the flat plate with square rods(turbulence promoter) have been experimentally investigated. The effects of jet Reynolds number (Re=3900, 5800, 7800, 9700), dimensionless slot-to-plate distance(H/B=4, 6, 8) clearance(c) between square rods and the plate, and the length(d) of a side of the square rod were examined. Measurement or heat transfer rate were conducted using naphthalene sublimation technique. When square rods were inserted over the heat transfer surface, heat transfer rate was slightly increased in the wall jet region.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.3
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• pp.61-72
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• 1996

In this paper, the driver seat comfort of eight automobiles was studied. The joint angles and anthropometric data of eleven subjects sitting on the seating buck were investigated using the instrument devices such as scale, goniometer, vernier calipers, protractor, Martin set. The joint angles of the most comfort posture were found by experiment and compared with previous studies. The anthropometric data of Korean(1992 year surveys) and American(1970∼1974 year) were applied to evaluate the driver seat layout of Korean automobile. The joint angles of the most comfort posture for eleven subjects were obtained with experimental results. The joint angles were agreed with reference angles. The driver seat layout was not suited to seat length and acceleratorseatpan forward distance in 5 percentiles female, pedal separation and seatpan-roof height in 95 percentiles male. Korean automobiles were not suited to seatpan length and steering wheelseatpan clearance, floor-roof height for American 95 percentiles male. The driver anthropometric dimensions were more suitable to middle size than small size automobiles.

• Tribology and Lubricants
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• v.12 no.2
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• pp.8-19
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• 1996

Scroll compressor using a slide bushing type radial compliant crank mechanism is modelled, and it's dynamic behaviour characteristics are analyzed. Sealing forces generated in the flank surfaces of the orbiting scroll depending on the distance, e, from slide bushing center to crank pin center are calculated. From the stable condition of orbiting scroll for the moment equilibrium in tangential direction, the range of e is determined as 0$r_o$. Transient response of a crankshaft supported by two journal bearings is investigated, considering applied load, moment, and unbalance force by eccentric mass. As a result, conical whirl mode with circular orbits are obtained. The characteristics of journal orbits and frictional losses are calculated with a variation of viscosity and bearing clearance.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.6
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• pp.227-233
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• 2002

A vehicle longitudinal control strategy with guaranteed string stability for vehicle stop-and-go(SG) cruise control is presented in this paper. The SG cruise control systems should be designed such that string stability can be guaranteed in addition to that every vehicle in a string of SG cruise control vehicles must track any bounded acceleration and velocity profile of its preceding vehicle with a bounded spacing and velocity error. An optimal vehicle following control law based on the information of the 1311owing distance (clearance) and its velocity relative to the vehicle ahead (relative velocity) has been used and string stability analysis has been done based on the control law and constant time gap spacing policy, A validated multi-vehicle simulation package has been shown that the string stability analysis using the approximate model of the vehicle servo-loop which includes vehicle powertrain and brake control system dynamics is valid in the design of the SG cruise control law with guaranteed string stability.

• Proceedings of the KIEE Conference
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• 1997.07e
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• pp.1804-1806
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• 1997

Route conditions, applied voltage and the condition of stringing conductors should be considered in determining standard types and skeleton diagrams of towers. In skeleton diagrams the necessary number of insulators and the air clearance have been decided by the results of studies on insulation coordination. Galloping, sleet-jumping, sag characteristics and the possibility of closeness of conductors should be considered according to the condition of stringing conductor and the span. After reviewing those factors, it is necessary to determine the minimum vertical and horizontal distance for the safety of transmission lines under any circumstances. Also it should be economical.

• Korean Journal of Computational Design and Engineering
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• v.3 no.1
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• pp.1-14
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• 1998

This paper introduces non-manifold offsetting operations, which add or remove a uniform thickness from a given non-manifold model. Since these operations can be applied to not only solids but also wireframe or sheet objects, they are potentially useful for pipeline modeling, sheet metal and plastic part modeling, tolerance analysis, clearance checking, constant-radius rounding and filleting of solids, converting of abstracted models to solids, HC too1 path generation and so on. This paper describes mathematical properties and algorithms for non-manifold offsetting. In this algorithm, a sufficient set of tentative faces are generated first by offsetting all or a subset of the vertices, edges and faces of the non-manifold model. And then they are merged into a model using the Boolean operations. Finally topological entities which are within offset distance are removed. The partially modified offsetting algorithms for wireframes or sheets are also discussed in order to provide more practical offset models.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1265-1268
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• 2009

In this paper, the effect of a flow barrier and bypass on the cooling performance for a straight fin heat sink is presented. Both side directions and upward direction of bypass are controlled using various ducts which have different width and heights. In addition, a flow barrier is used to control flow toward heat sink. Through experiments, the distance from leading edge of a heat sink to a flow barrier is varied for various bypasses under fixed volume flow rate condition. This study shows possibility to improve cooling performance when bypass and a flow barrier exist.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.712-717
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• 2005

In this thesis, it is investigated that the effect of the cross linked polyethylene(XLPE) insulator do to breakdown phenomenon by the insertion of the needle and bar electrode into XLPE which is used of electric power cable for the ultra-high voltage. The result of the partial discharge properties in the specimen showed that in case of the insertion of needle or bar electrode into XLPE, the effect of the inner discharge become large when the air void is bigger then the clearance of the electrode of the specimen. The closer the distance between the insulator and needle electrode, it takes less time to the insulation breakdown.

• The korean journal of orthodontics
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• v.19 no.3
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• pp.79-86
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• 1989

The wires for initial alignment purposes require a combination of excellent strength, excellent springiness, and a long rang of action. The variables in selecting appropriate arches for alignment are the arch wire material, its diameter, and the distance between attachments. The principle that there should be 0.02 inch clearance for initial wires means that an .016 diameter wire is the largest that should be considered for initial alignment in the .018 slot system. The three major possibilities for alignment arches are multistranded steel wires, nickel-titanium wires, and single-stranded steel wires with loops. The excellent choice for initial alignment in .018 bracket is .014 steel wire with loops.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.545-551
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• 2006

Along with the steady development of Korean Railway construction technology, Contemporary society needs more modernized structures which can meet not only structural value but also aesthetic and environmental value. To follow this demand of society, Pre-Stressed Concrete U-girder bridge(Somg-Lim Gyo, L=330m) is introduced in 'JINJOO-KWANGYANG RAILWAY CONSTRUCTION PROJECT'. On the environmental point of view, the huge noise due to the operation of train can be reduced remarkably by the side beam of U-girder which is high enough to substitute soundproofing wall. Moreover, by aesthetic variation of the shape of outer beams and coping of piers, the exterior view of the bridge can be improved and in accordance with surroundings. Pre-Stressed Concrete U-Girders which are built up above the outer sides of slab deck make easier to secure the clearance of a bridge and make it possible to lower the distance of centroid between superstructure and railroad tracks.