• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.2
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• pp.85-96
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• 2017

In this paper, a 2~18 GHz wideband 6-port network is designed and fabricated to extend the measurement frequency bandwidth of noise parameter measurement method using 6-port network. In order to design a broadband 6-port network, a wilkinson power divider and a directional coupler with wideband characteristics are designed. The wilkinson power divider is designed as a three-section structure to achieve wideband characteristics. The direction coupler is designed as a three-section structure and slot-coupled structure using multi-layer substrate to obtain wideband characteristics. A wideband 6-port network is designed and fabricated combining the designed power divider and coupler. The measured results of the fabricated 6-port network for the 2~18 GHz band show characteristics applicable to the noise parameter measurement method.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.5
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• pp.188-196
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• 1997

Many researchers have developed the measurement technique of in-cylinder flow characteristics and found the effect of intake port geometries on engine performance. The flow characteristics of four-valve cylinder head were examined in a steady flow rig for different intake ports. Tumble intensity of intake configurations with different entry angles were quantified with a tumble meter. The velocity and angular momentum distributions in the tumble adaptor were measured under steady conditions with PIV(Particle Image Velocimetry). We have obtained the results that flow structure becomes complicated by valve interference at low valve lift. As the valve interferences were reducing and the flow pattern changed to large vortex structure with tumble direction, intake ports with different entry angles have different tumble centers. Tumble eccentricity of intake port with low entry angle was large, so that the port had relatively much angular momentum compared to others which was expected to improve combustion performance.

• 한국연소학회:학술대회논문집
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• 2005.10a
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• pp.314-319
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• 2005

In this study, the combustion characteristics were investigated with the variation of design factors on multiple slit gas burner. The design factors consist of slit height, width, spacing, and inner length. The combustion characteristics were made analysis of the CO emission and NOx emission by using CO analyzer and NOx analyzer. The lower perimeter to area and the narrow spacing extends the lift-flame limit. The CO emission increases with the increasing perimeter to area ratio at the same condition. The NOx emission is found to be less significant with the port perimeter to area ratio. The flame interference might highly depend on the spacing and port perimeter to area ratio, and it also affects the burner performance.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.10a
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• pp.242-247
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• 2003

An experimental study presents characteristics of combustion in a combustion chamber by port deactivation valve for economy and emissions standards. In order to use combustion properties data it is necessary to build some data base, which use cylinder pressure sensor, etc. Port deactivation valve has been developed to satisfy requirement of achieving sufficient swirl generation to improve the combustion. A feasibility and necessity of combustion pressure based cylinder spark timing control has been examined. So, this was obtained the Coefficient of Variation(COV) and the mass-burned(MFB). The characteristics of pressure ratio fraction is similar to that of mass-burned fraction. Using the results of the test, the effects of the combustion chamber can be improved combustion stability by port deactivation.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.2
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• pp.56-63
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• 2011

This paper presents the method of giving hysteresis characteristics to the digital input port of microprocessors or micro-controllers and it's design procedures. And this paper shows the example of circuit design and the effect of this method by experiments. Presented method has advantages : By the additional one port and two resistors, input port can have hysteresis characteristics and hysteresis band is larger than TTL, CMOS schmitt trigger gates.

• Journal of Korea Port Economic Association
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• v.24 no.4
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• pp.1-23
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• 2008

In order for Busan New Port to secure more trading volumes than the competing ports at home and abroad, an alternative plan for the new port management policy needs to be sought. By the way, aiming to minimize trial and error while maximizing effect in establishing and driving the new port management policy, there is necessity of referring to the developmental strategies of the advanced ports such as Singapore and Hong Kong that are possessing the globally leading position as well as maximizing the substantial value added and the employment-creation effect even qualitatively. Accordingly, the purpose of this study is to propose for a reasonable development strategy for Busan New Port in line with conditions and characteristics of Busan New Port by comparing and analyzing conditions and characteristics of these two advanced ports and by comparative analysis on the developmental strategy according to this.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.93-96
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• 2008

This study was performed for merge characteristic of Hybrid Rocket with multi-port. PE(Poly Ethylene) is fuel with 4 and 5 port grain and GOX(Gas Oxygen) is oxidizer. This study according to number of ports The multi-port grain merge with other grains during a combustion, then Hybrid Rocket performance is changed by change of a combustion area.

• Journal of computational fluids engineering
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• v.4 no.3
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• pp.21-27
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• 1999

In this paper, tile characteristics of flow resulting from the configurations of piston head and intake-port of the cylinder in a gasoline-direct-injection engine are investigated numerically. Calculations are carried out from intake process to the end of compression. GTT code which includes the third order upwind Chakravarthy-Osher TVD scheme and κ-ε turbulence model with the law of wall as a boundary condition. As a result, a piston head with a smaller radius of curvature and larger radius gives stronger reverse tumble. It is also shown that as the maximum tumble ratio increases by the configuration of the intake-port the tumble ratio at the end of compression stroke increases. It is concluded that flows at the end of compression stroke can be controlled by the optimum design of intake-port and piston head.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.15 no.4
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• pp.38-44
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• 2007

This paper describes the structural safety of solid fuel in the Hybrid Rocket Motor (HRM). Hybrid rocket combustion has the distinct regression characteristics which include the process of thermal pyrolysis and fuel vaporization. Most of all, this regression characteristics would structurally affect the strength of the fuel having a multi-port configuration, and even may cause the breaking from the fuel grain. This problem would probably influence the performance and operating safety of HRM. Therefore, for the safe operation of HRM, the critical port radius which determines the structurally safe region was discussed from the heat analysis of the solid fuel.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.7
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• pp.549-556
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• 2001

Heat flow characteristics during hot water extraction process was studied experimentally. Data were taken at various outlet port type for the fixed inlet port type, inlet-outlet temperature differences and mass flow rates. In this study, the temperature distribution in a storage tank and an outlet temperature were measured to predict a flow pattern in the storage tank, and a hot water extraction efficiency was analysed with respect to the variables dominating a extraction process. Experimental results show that the extraction efficiency is high in a low flow rate in case of using modified distributor I(MDI) as a outlet port type.