• Journal of the korean Society of Automotive Engineers
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• v.14 no.3
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• pp.80-89
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• 1992

An experimental study of in-cylinder of flow and combustion characteristics in two gasoline engines of different intake ports which are denoted as original port and masked shroud head (MSH) ports is presented. The flows generated by the MSH and the original port are invest- igated by laser Doppler velocimeter(LDV) under steady flow and motoring (non-firing) condit -ions. Combustion characteristics with different swirl levels produced by two intake ports are analyzed by combustion pressure measurement and statistical calculation. The swirl inside the cylinder of the MSH port engine is found to be much higher than the original port, and the MSH has a large eddy motion of cylinder diameter size. Using ensemble average method to valuate engine turbulence under motoring condition, the MSH port engine is shown to have h -igher turbulence intensity than the original port, so that the effect of the MSH port on fast burn is shown. Also the cyclic variations of peak pressure and the reaching time in the MSH port are apparently reduced.

• 한국연소학회:학술대회논문집
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• 2002.06a
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• pp.199-203
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• 2002

In this paper, the effects of water contents on combustion characteristics of paper sludge and capacity of fluidized bed combustor(FBC) were investigated using 0.26m diameter, 1.75m height pilot-plant scale combustor. Combustion tests of paper sludge containing water contents between 40wt% and 50wt% were performed. The temperature and emission variation, the pressure inside combustor were measured to monitor the fluidization quality. The experimental results showed that 30kg/hr feeding rate of sludge containing water up to 45wt% was preferable for this system. Sludge loading rate, heat release rate were calculated from experimental data as major parameters showing FBC capacity. Comparsion with sludge loading rate from other source was also performed

• 한국연소학회:학술대회논문집
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• 2012.11a
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• pp.329-332
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• 2012

The droplet behavior of 83.9 wt.% HAN water solution was investigated experimentally with various ambient temperature and nitrogen environment. At the initial stage of evaporation under thermal decomposition temperature of HAN, gradual decreasing of droplet diameter was observed. After that, the droplet started to expand due to the internal pressure build up by water nucleation inside the droplet. The micro explosion was observed at higher temperature than the decomposition temperature of HAN and the remaining droplet showed similar behavior of single composition droplet. The decreasing rate was augmented as the ambient temperature increasing.

• International Journal of Naval Architecture and Ocean Engineering
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• v.5 no.4
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• pp.625-634
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• 2013

Energy is a direct restriction to the working life of an underwater mooring platform (UMP). In this paper, a vertical axis water turbine (VAWT) is designed to supply energy for UMPs. The VAWT has several controlled blades, which can be opened or closed by inside plunger pumps. Two-dimensional transient numerical studies are presented to determine the operating performance and power output of the turbine under low ocean current velocity. A standard k-${\varepsilon}$ turbulence model is used to perform the transient simulations. The influence of structural parameters, including foil section profile, foil chord length and rotor diameter, on the turbine performance are investigated over a range of tip-speed-ratios (TSRs). It was found that turbine with three unit length NACA0015 foils generated a maximum averaged coefficient of power, 0.1, at TSR = 2.

• Journal of Veterinary Clinics
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• v.18 no.2
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• pp.174-177
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• 2001

A nine-month-old male ostrich (Struthio camelus) exhibited loss of appetite and dyspnea for 10 days, followed by emaciation and death. Grossly, multiple white nodules measuring 1-3 mm in diameter were observed in the surface of and inside of the lung and in the mucosa of the air sac. Microscopically, the granuloma formations were observed in the lung and air sac. The core of granuloma consisted mainly of macrophages and fibroblasts. The thin layer comprising the giant cells and macrophages surrounded the granuloma. By Periodic acid Schiff reaction, mycelia were detected especially in the core of granuloma. From the present results, the causative agent inducing the death of an ostrich was thought to be Aspergillus sp. This is the first report of the occurrence of acute Aspergillus pneumonia (brooder pneumonia) in an adult male ostrich in Korea.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1998.04a
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• pp.69-76
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• 1998

A precision wear tester is developed to measure the wear rate of a high friction and high pressurized cylinder. The tester consists of indentor system and optical measuring system. The indentor system has two diamond indentors so that they make indents on the inside of the cylinder by using compressed air system. The X-Y-$\theta$ stage of the measuring system can trace the positions of the indents and can measure the diameters of them. The variation of the diameter of each indent after test is converted into the wear rate.

• Journal of ILASS-Korea
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• v.17 no.2
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• pp.57-63
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• 2012

For reduction of CO, NOx and soot emission emitted by diesel diffusion combustion, the authors focused on injection actuator to improve fuel availability inside combustion chamber. In this study, it was investigated the internal dynamic characteristics of two-stage injection with diesel injectors with different driving type for the common rail direct injection by using the AMESim simulation code. The analysis parameter defined such as fuel pressure, injection hole's diameter and driven voltage. As the results, it was shown that the piezo-driven injector had a faster response and had better control capability than the solenoid-driven injector. It was found the piezo-driven injector can be utilized effectively as multiple injector than solenoid-driven injector.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2001.02a
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• pp.121-124
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• 2001

The research results on the superconducting magnet for whole body MRI are presented. The magnet consists of main coil with 6 solenoid coils, shielding coil with 2 solenoid coils and 6 sets of cryogenic shim coil. The ferromagnetic shim assembly is installed on the inside wall of the room temperature bore for shimming inhomogeneous field components generated due to manufacturing tolerances, installation misalignments and external ferromagnetic materials near the magnet. Also, the magnet is enclosed with the horizontal type cryostat with 80cm room temperature bore to keep the magnet under the operating temperature. The magnetic field distributions within the imaging volume were measured by the NMR field mapping system. Through the test, the central field of magnet was 1.5 Tesla and the field homogeneity of 9.3 ppm has been obtained on 40cm DSV(the diameter of spherical volume) and using this magnet, comparatively good images for human body, fruits and water phantoms have been achieved.

• The KSFM Journal of Fluid Machinery
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• v.9 no.6 s.39
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• pp.29-34
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• 2006

Propeller type pump has been widely used for pumping water in agricultural and manufacturing industry. Since a propeller type pump contains a screw impeller inside a circular casing, the numerical analysis becomes complex. However, the accurate prediction of viscous flow is essential for computing hydrodynamic performances. To analysis the flow and the performance of the propeller type pump, the present work has solved 3D incompressible RANS equations on the multiblocked grid. From the present calculation, small amount of flow separation was shown near hub and the flow was recovered to nearly uniform inflow after one diameter downstream. Torque and thrust coefficient were computed and compared with experiments.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.18 no.2
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• pp.68-71
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• 2008

AlN crystals were grown by the sublimation process. As grown AlN crystals were the polycrystalline boule in the form of the agglomerate of small AlN single crystalline AlN. As-grown AlN boule has a length about 2${\sim}$3 mm long and a diameter of 1 inch. The carbon impurities were observed on the surface and inside of the grown AlN crystals and the growth behavior was investigated by optical microscopy and SEM observation.