• Journal of the Korean Crystal Growth and Crystal Technology
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• v.17 no.2
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• pp.82-89
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• 2007

Glass-ceramics were fabricated by heat-treating a glass at $700^{\circ}C$/10hr which was obtained by melting a glass frit mixed with $40{\sim}80 wt%$ EAF dust at $1300^{\circ}C$/1hr. Dependence of crystal phase and bonding state change upon a compositional change and heat treatment condition were studied and the results was connected to the toxic characterization leaching procedure (TCLP) test data to investigate a chemical durability of the specimens. Increasing dust in a glass shifted the peak around $1000cm^{-1}$ to the lower frequency which was composed of two vibration peaks for the nonbridging oxygen at $960cm^{-1}$ and the bridging oxygen at $1050{\sim}1060cm^{-1}$. Also, the $B_2O_3$ structure of boroxol ring changed to a tetrhedral-, trigonal- and di-borate with dust addition. The Fe-O peaks in the glass-ceramics were observed which is consitent with XRD results of spinel formation. The surface of glass after TCLP test was severely cracked while there was no cracks on a glass-ceramics after TCLP test so the chemical durability of the glass-ceramics is superior than that of glass. The leaching concentration of Fe for the glass-ceramics containing EAF dust 80 wt% is 1/15 times lower than that of glass. The Zn leaching concentration fur the glass-ceramics containing dust < 70 wt% was higher than that of glass but its trend was reversed for the specimen of dust content > 80 wt% which could be concluded as correlated with occurrence of willemite phase.

• Research in Plant Disease
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• v.12 no.2
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• pp.144-147
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• 2006

Egg yolk immunoglobulin (IgY) is much widely used in medical fields, but its use in serology of plant viruses is much limited. We produced an IgY against pepper mild mottle virus (PMMoV) and applied it to several serological tests. Polyclonal antibodies were obtained from the egg yolk of chicken immunized with a total of 2mg of purified PMMoV over 2 months. The titers of antibodies were measured with the ring-test over six months after the first injection. The highest.titers of IgY was 1/2,560 at 2 months after the first injection. Approximately 60-80 mg of IgY were obtained from one egg yolk. Using the IgY, 1ng/ml of purified PMMoV was detected with the indirect ELISA. Gelrite gel double diffusion test, ELISA and tissue immuno-binding assay employing IgY gave similar sensitivity and specificity to those of IgG developed in rabbit. Therefore, the IgY which can be obtained in large quantities from a chicken, might be useful for the antibody production and the serology of plant viruses.

• Journal of the Korean Society of Propulsion Engineers
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• v.14 no.5
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• pp.57-64
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• 2010

A performance test of inter propellant seal for a 75 ton class turbopump is conducted using water to evaluate leakage and endurance performance. Each part of fuel pump side and oxidizer pump side for a prototype inter propellant seal has been tested for verifying endurance performance during total accumulated test time 2,100 sec in water. The fuel pump side part with one-stage seal of carbon floating ring shows average leakage rate 13.7 gram/sec under average seal differential pressure 9.4 bar. On the other hand, the oxidizer pump side part with two-stage seal assembly of carbon floating rings shows average leakage rate 7.3 gram/sec under average seal differential pressure 9.5 bar. After the endurance performance test, the inter propellant seal shows good physical condition. A leakage performance test of the inter propellant seal for cryogenic environment will be performed using LN2 in the near future.

• Structural Engineering and Mechanics
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• v.45 no.3
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• pp.337-354
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• 2013

For shield TBM (Tunnel Boring Machine) tunnel lining, the segment joint is the most critical component for determining the mechanical response of the complete lining ring. To investigate the mechanical behavior of the segment joint in a water conveyance tunnel, which is different from the vehicle tunnel because of the external loads and the high internal water pressure during the tunnel's service life, full-scale joint tests were conducted. The main advantage of the joint tests over previous ones was the definiteness of the loads applied to the joints using a unique testing facility and the acquisition of the mechanical behavior of actual joints. Furthermore, based on the test results and the theoretical analysis, a mechanical model of segment joints has been proposed, which consists of all important influencing factors, including the elastic-plastic behavior of concrete, the pre-tightening force of the bolts and the deformations of all joint components, i.e., concrete blocks, bolts and cast iron panels. Finally, the proposed mechanical model of segment joints has been verified by the aforementioned full-scale joint tests.

• International Journal of Aeronautical and Space Sciences
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• v.17 no.1
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• pp.120-131
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• 2016

The full results of troubleshooting process related to the flight control system of a tilt-rotor type UAV in the flight tests are described. Flight tests were conducted in helicopter, conversion, and airplane modes. The vehicle was flown using automatic functions, which include speed-hold, altitude-hold, heading-hold, guidance modes, as well as automatic take-off and landing. Many unexpected problems occurred during the envelope expansion tests which were mostly under those automatic functions. The anomalies in helicopter mode include vortex ring state (VRS), long delay in the automatic take-off, and the initial overshoot in the automatic landing. In contrast, the anomalies in conversion mode are untrimmed AOS oscillation and the calibration errors of the air data sensors. The problems of low damping in rotor speed and roll rate responses are found in airplane mode. Once all of the known problems had been solved, the vehicle in airplane mode gradually reached the maximum design speed of 440km/h at the operation altitude of 3km. This paper also presents a comprehensive detailing of the control systems of the tilt-rotor unmanned air vehicle (UAV).

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1993.04a
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• pp.39-53
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• 1993

The minimum oil film thickness(MOFT) in the connecting-rod bering of a 1.5 liter, L-4, gasoline engine is measured up to 5500 rpm and calculated to study the dynamically loaded engine bearing. Short bearing approximation and Mobility method are used for theoretical analysis of oil film charactrtistics. And cylinder pressure, crank-pin surface temperature and bearing tenp ture are measured as the input data of theoretical analysis. The MOFT are measured by the total capacitance method(TCM). To improve the reliability of the test results, a reasonable detmuuination method of bearing clearance is introduced and used, and the effects of cavitation and aeration on the test results are neglected. The crankshaft is grounded by means of a slip ring. A scissor type linkage system was developed to measure the MOFT and bearing temperature. The effects of engine speed, load and oil viscosity on the measured and calculated minimum oil film thicknesses are investigated at 1500 to 5500 rpm. From the comparison between the measured and calculated MOFT, it is found that a qualitative similarity exists between them, but in all cases, the measured MOFT are smaller than those calculated.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.31 no.3
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• pp.47-53
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• 1999

The effect of coating of liner components with oxidized starch on the properties of corrugated box was examined . Coating was carried out on liner components of B flute, single-wall corrugated board(SK180/S120/K200) , and corrugated box was made from the treated corrugated board. Box was made in a regular slotted container (RSC) style, and box compression strength was determined in the direction of top-to-bottom compression. The compression strength of box coated on outside liner component showed 15.4% improvement for 1.58g㎡ coating. On the other hand, the strength of box coated on outside liner component showed only 1.45% improvement for 1.41g/㎡ coating and 3.46% improvement for 2.32g/㎡ coating. Coating on inside liner component with oxidized starch at low coating weight more significantly improved box compression strength than coating on outside liner component, and the improvement was marked at the coating weight of 1.5-2.5g/㎡. In estimating top-to-bottom box compression strength, the experimental values were closer to the calculated values from McKee's equation suing edgewise compression strength of the combined board measured by column crush test than those from Kellicutt's equation using compression strength of component paperboards measured by ring crush test.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.4
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• pp.121-129
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• 1997

Gear train system test rig of power circulating type was fabricated, and systematic experiment for measuring dynamic characteristics of the planetary gear trains in the low speed region has been carried out using the test rig. The measured parameters are fillet strains of the sun gear and ring gear, carrier displacements, torques of the input and output shafts. The results are as follows : i) Even though the loading torque is constant, torque variation has been observed on the input and output hafts, ii) The variation of the torque has two frequency components, i.e. lower one of the input shaft rotation and higher one of the two teeth meshing, iii) The variation of the fillet strains shows the same tendency as that of the torque, iv) The loci of the carrier depend on the torque and rotational speed.

• Nuclear Engineering and Technology
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• v.42 no.2
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• pp.193-202
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• 2010

In order to study the cladding properties of zirconium after a loss-of-coolant accident (LOCA)-simulation oxidation and water quenching test, commercial Zircaloy-4 and two kinds of HANA claddings were oxidized at temperatures ranging from $900^{\circ}C$ to $1250^{\circ}C$ and exposed for 300 s, and then cooled to $700^{\circ}C$ before quenching. Microstructural observations were made to evaluate the matrix characteristics with the chemical compositions after the LOCA-simulation test. Ring compression testing was then performed to compare the ductile behaviour of the HANA and Zircaloy-4 claddings. An X-ray diffraction (XRD) analysis was carried out for temperatures ranging from room temperature to $1250^{\circ}C$ for the oxide layer to verify the oxide crystal structure at each oxidation temperature.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.153-156
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• 2009

The pitch and yaw axis controls of Kick Motor, KLSV-I second propulsion system, was provided by the flexible seal that consists of alternate laminate of natural rubber and composite reinforcements between forward and aft ring. A hydrostatic actuating test has been conducted to evaluate a performance of the manufactured flexibke seal before it is assembled at the nozzle. Through the tests, we have verified an actuation torque and axial displacement of the flexible seal according to pressure variation. The actuation torque and axial displacement of all flexible seal is shown below 60kgf-m/deg at without pressure and 6mm at MEOP respectively.