• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1993.10a
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• pp.267-276
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• 1993

A kinetmatic stirling engine with a domed heater was designed, fabricated and test. In designing and fabrication of the engine various problems were confronted and solved. Among various parts of the engine, cooler and main seal needed sophisticated techniques to fabricated in order to prevent leakage of working gas from the parts and to ensure their proper functions in the engine. The engine had a series of experiment at various working gas pressure, heater temperatures and engine speeds to evaluate its performance. Indicated and brake power outputs and indicated and brake thermal efficiencies were determined from the experimental data. The engine resulted a little inferior performance to that of the GPU-3 engine of which performance was well reported . Several recommendations were made to improve the performance of the engine during the evaluation of its performance.

• Tribology and Lubricants
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• v.14 no.1
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• pp.45-53
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• 1998

Friction and wear test for two kinds of Cu-based sintered metallic friction material against cast iron disk was carried out by plate-on-disk type friction and wear tester to investigate the friction and wear characteristics of brake system in severe condition. In this experimental study, the counter specimen was cast iron which is being used generally in brakes of heavy duty equipments. Test friction materials were A type which was manufactured by foreign company and B type by domestic company. Friction coefficient and wear volume were measured and compared with each other. The experiment was performed under room temperature. The worn surface of cast iron disk and friction material were observed by scanning electron microscope. The temperature of surface of disk was measured continuously by the non-contacting thermometer. It was found that A type friction material had stable friction coefficient over the wide range of sliding condition, but B type friction material had unstable friction coefficient and lower value of 0.2 under the severe sliding condition.

• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.222-224
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• 2005

In the development of Antiskid Brake System(ABS) for a fixed-wing aircraft, the braking efficiency is the most essential parameters to evaluate the ABS, especially in slippery road conditions. The braking distance and landing distance of the aircraft depends on it. Since the ABS has been designed and implemented as a subsystem of the aircrafts, the braking performance was evaluated under dynamometer test, where the dynamometer emulates the aircraft mass. Under simulated wet road conditions, the dynamometer starts to be braked. This paper suggests practical braking efficiency calculation methods and the results and finally compares each method.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.583-589
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• 2010

This paper describes the design process and the test of split wheel-mounted brake discs for high speed train with maximum speed 180km/h. A disc set composed 2 disc rings and individual rings are partitioned into 3 pieces with the same circumferential angle. Because partitioned disc rigs are exposed to severe centrifugal force as the vehicle speed increase, finite element analyses used in the design process to ensure mechanical safety. A prototype was verified its mechanical safety through the spin test up to 250km/h. 2 prototypes for 1 wheelset are mounted to Korean Tilting Train(TTX) and have been running over 15,000km

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.57.2-57
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• 2002

1. Introduction 2. Dynamics of Aircraft Landing 3. ABS Control Unit 4. Test 5. Conclusions

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.4
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• pp.292-299
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• 2017

The KUH-1's Wheel Brake Assembly which is Brake System is an essential component to perform flight mission for pilot. It has function of taxing, differential braking and parking to sustain landing capability. However, the skid and abrasion of tire were occurred in mass-produce operation. Also, if it is occurred on the ground, the flight can not be performed. In this case, the defect is a major cause of the decrease in the operation rate of aircraft. In this paper, the cause of the defect in flight was identified and the failure process was organized. Also, it describes design improvements which was derived from troubleshooting and suggests verification results of flight test.

• Environmental Engineering Research
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• v.24 no.4
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• pp.680-689
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• 2019

Temperature effects on the generation of brake wear particles from railway vehicles were generated, with a particular focus on the generation of ultrafine particles. A real scale brake dynamometer test was repeated five times under low and high initial temperatures of brake discs, respectively, to obtain generalized results. Size distributions and temporal patterns of wear particles were analyzed through visualization using clustered heatmaps. Our results indicate that high initial temperature conditions promote the generation of ultrafine particles. While particle concentration peaked within the range of fine sized particles under both low and high initial temperature, an additional peak occurred within the range of ultrafine sized particles only under high initial temperature. The timing of peak occurrence also differed between low and high initial temperature conditions. Under low initial temperature fine sized particles were generated intensively at the latter end of braking, whereas under high initial temperature both fine and ultrafine particles were generated more dispersedly along the braking period. The clustered correlation heatmap divided particle sizes into two groups, within which generation timing and concentration of particles were similar. The cut-off point between the two groups was approximately 100 nm, confirming that the governing mechanisms for the generation of fine particles and ultrafine particles are different.

• The Journal of Korean Physical Therapy
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• v.23 no.1
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• pp.7-11
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• 2011

Purpose: Driving is essential to maintain independent living status in modern times. Many patients want to know when they can drive again, but it's only possible if they have the ability to control lower extremity muscles. In this study, we compared the effects of velocity on onset time of lower extremity muscles during driving tasks. Methods: Twelve participants (5 male, 7 female) were enrolled. EMGs were used to test the onset time of lower extremity muscles; tibialis anterior, soleus, rectus femoris. To analyze the data, we used two way ANOVA. Results: According to brake pedaling velocity, there was a significant difference in brake response time (p<0.05). Further, when comparing the lower extremity muscles, there was a significant difference in onset time (p<0.05). The order of muscle recruitment was tibialis anterior, rectus femoris, and soleus for achieving maximal velocity, but the order was rectus femoris, tibialis anterior, soleus for achieving submaximal velocity. Conclusion: Brake pedaling velocity has significant effects on onset time of muscle contractions in the lower extremities. We suggested that a future study needs more subjects and more detailed research such as evaluat-ions of visuo-motor coordination and fine motor dexterity.

• Tribology and Lubricants
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• v.31 no.2
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• pp.42-49
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• 2015

Because of the growing need for high-speed transport options such as trains and aircraft, there is increasing demand for technology related to high-speed trains. Among them, braking systems are important in high-speed trains in terms of reliability. Especially, the disk brake system, in use in most high-speed trains, transforms kinetic energy into thermal energy and noise. Therefore, the material properties of both the friction materials and disks are expected to influence the tribological characteristics. In this paper, the tribological characteristics depend on the hardness of the brake disks between the Cu-based sintered metallic friction material and the heat-treated heat-resisting steel disks. A lab-scale dynamometer used to perform braking tests at a variety of braking speeds using dry conditions. The test results revealed that the hardness of the disks affects the friction coefficients, friction stabilities, and wear rates. Thus, the brake system using the heat-resisting steel disk requires proper heat-treatment. These differences are considered to be caused by the change in tribological mechanisms and the generation of an oxide layer on the friction surfaces. The oxide layers on the friction surfaces are confirmed to Fe₂O₃ by x-ray diffraction (XRD) and scanning electron microscope-energy dispersive spectroscopy (SEM-EDS) analysis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.3
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• pp.593-598
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• 2008

It was made a friction material of various kinds by adding 10%, 20% and 30% of reduced iron. It was obtained by a connected-reduced process in a blast furnace sludge and oxidized iron, instead of $BaSO_4$, which is already a used inorganic filling material among a component of a brake friction material. This was done by a basic physical property test, a friction performance test to use a brake dynamometer. Moreover, in case of an add in the friction material, instead of using $BaSO_4$, the more expensive filling material, the reduced iron was also better because it has an excellent a friction property of an exothermic temperature, wear, etc. was 10%. At G1 and G3 specimens, a shear strength and a bonding strength of the friction material was decreased to be able to increase an amount of the blast furnace sludge and the reduced iron, but an application of all friction materials appeared enough strength.