• Aerospace Engineering and Technology
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• v.13 no.2
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• pp.73-79
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• 2014

During developing cubesat flight software, Communication test between cubesat and ground station is needed. For this, we have constructed indoor ground station without outdoor antenna for decreasing total cost and time. In this time, if output power of ground station is high, it will affect for cubesat transceiver to be fail. For solving this problem, ground station must be designed for output power of it to be lower than input power of cubesat satellite, and it must be verified. In this paper, first, we describe cubesat indoor ground station using UHF and VHF. Second, we describe output power decreasing test for indoor operation of ground station by attaching attenuators in the end of the output connector.

• Korean Chemical Engineering Research
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• v.50 no.5
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• pp.778-782
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• 2012

Until a recent day, degradation of PEMFC MEA (membrane and electrode assembly) has been studied, separated with membrane degradation and electrode degradation, respectively. But membrane and electrode were degraded coincidentally at real PEMFC operation condition. Therefore in this work, AST (Accelerated Stress Test) of MEA degradation was done at the condition that membrane and electrode were degraded simultaneously. There was interaction between membrane degradation and electrode degradation. Membrane degradation reduced the decrease range of catalyst active area by electrode degradation. Electrode degradation reduces increase range of the hydrogen crossover current and FER (Fluoride Emission Rate) by membrane degradation.

• Journal of Welding and Joining
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• v.30 no.6
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• pp.113-119
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• 2012

Ultrasonic bonding is the novel packaging method for flip-chip with high yield and low-temperature bonding. The bonding module is a core part of the bonding machine, which can transfer the ultrasonic energy into the bonding spot. In this paper, we propose topology optimization technique which can make new design of boding modules due to the constraints on resonance frequency and mode shapes. The designed bonding module using topology optimization was fabricated in order to evaluate the bonding performance and reliable operation during the continuous bonding process. The actual production models based on the proposed design satisfied the target frequency range and ultrasonic power. The bonding test was performed using flip-chip with lead-free Sn-based bumps, the results confirmed that the bonding strength was sufficient with the designed bonding modules. Also the performance degradation of the bonding module was not observed after the 300-hour continuous process with bonding conditions.

• Korean Journal of Adult Nursing
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• v.20 no.3
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• pp.395-405
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• 2008

Purpose: The purpose of this study was to develop a Web-based flash content for fighting spirit promotion and to test its effect on cancer patients' fighting spirit. Methods: The 15-minute long Web-based flash content was developed using the following 5 process: analysis, planning, development, program operation and evaluation stages and utilized the multiple edition and revision processes from December 2005 to August 2006. The evaluation was done by one group pretest-posttest design. Study subjects were 17 cancer patients undergoing chemotherapy. The group were received a 2-week intervention, a day weekly, and measured the variables at baseline, 4 weeks later. The study was performed from August 2006 to February 2007 at a cancer center in Korea. Fighting spirit was measured by Mini-MAC(Mental Adjustment to Cancer). Data was analysed by descriptive statistics and paired t-test using SAS 9.13 program. Results: On the Web-based flash content, there are 4 menu bars that consisted of cancer diagnosis, symptom management, stress management, and cancer survivorship. The study group revealed significantly more fighting spirit than pre-test(t=-3.04, p=.008). Conclusion: This Web-based flash content can be utilized in psychosocial interventions for promoting fighting spirit in patients with cancer.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.6 no.1
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• pp.1-15
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• 2008

This study was designed to investigate the effect of treadmill exercise of low-intensity and high-intensity on the functional recovery and histological change in spinal cord injury rats. Sprague-Dawley rats were experimented(n=15) for this research. Spinal cord injury was induced by the NYU drop impacter device after laminectomy. After operation, rats were test at modified Tarlov scale at 3 days, and divided into the control group(n=5), experimental group I(n=5, low-intensity treadmill) and experimental group II(n=5, high-intensity treadmill). The rats were disciplined from 7 day through 21 day. Functional recovery was evaluated by the BBB scales and the Grid Walk test for the progressive locomotor recovery at 3, 7, 14, 21 days. Histopathological studies for the muscle in order to observation the change of damage and size of the organized surface which is visible visually it executed hematoxylin & eosin stain. According to the result of 4 weeks of treadmill exercise, group II showed improvement than group I of motor behavior after spinal cord injury.

• Journal of The Korean Society of Agricultural Engineers
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• v.51 no.5
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• pp.95-100
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• 2009

The water purification systems have been hardly used for agricultural purpose due to their complicated compositions and high costs for farmers, while only simple filtrations have been applied to irrigation systems in order to prevent the system from clogging problems. This study therefore developed a clean water supplying system, the Filter-Disinfection-Adsorption (FDA) system, especially for greenhouse cultivation of where low quality of water is available. This system has also been produced for providing convenience water to farmers in the areas of no water supply service systems for the purpose of washing their bodies or agricultural machineries after farm work. The FDA system consists of three stages of purification processes with an integral module, including disk and teflon filtrations and Ultraviolet (UV) sterilization processes. Indoor experiments were undertaken with a trial product of the FDA system to test its performance. The operation test of the process was performed as well as the condition check of each item including UV module, filters, control panel, pump, valves, etc. The results shows good performance of each test with no critical problems. The initial and maintenance costs were also analysed with other purification systems. From the comparisons, the FDA system found to be very economical and easy to use.

• Aerospace Engineering and Technology
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• v.6 no.1
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• pp.173-181
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• 2007

Radiated emission / susceptibility performance of the KSLV-I 2nd stage which are controlled from the unit level to the system level should be examined and managed all over the frequency ranges in order to ensure the normal operation of the SC, the 1st stage of the KSLV-I, ground support equipments which are installed at the space center, and other wireless communication networks. Not only unintentional electric field emissions from the KSLV-I system and its subsystems should be restricted to the levels less than the limits specified in the EMC requirements, but also proper test and evaluation method should be established, respectively. In this paper, radiated emission/susceptibility test limits, method, and test results of the KSLV-I 2nd stage engineering model are presented.

• Journal of Mechanical Science and Technology
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• v.15 no.5
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• pp.602-612
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• 2001

The equation of the particle collection efficiency proposed by Deutsch has been modified through the various experiments to correct the errors caused by the assumptions made for the equation. In order to get an modified Deutsch equation that can be applied to real conditions, a pilot scale electrostatic precipitator is used. The effects of operational variables on the particle collection efficiency are evaluated. Particle resistivity, gas temperature, moisture contents in gas, gas velocity and particle concentration are used as the operational variables. Two different types of coal fly-ash obtained from the fluidized bed combustor and the pulverized coal combustor are used as test particulate to evaluate the effect of the physiochemical and electrical characteristics of the particle on the particle collection efficiency. The experimental results are fitted with the modified Deutsch equation made by Matts-Ohnfeldt and the extended Deutsch equation made by E. C. Potter to evaluate the effect of the particle characteristics and the operation conditions on the particle collection efficiency of the electrostatic precipitator.

• Journal of the Korean Society of Visualization
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• v.12 no.1
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• pp.18-24
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• 2014

The Korea Atomic Energy Research Institute (KAERI) has a scaled-down moderator test program to simulate the CANDU6 moderator circulation phenomena during steady state operation and accident conditions. In the present work a preliminary experiment using a 1/8 scaled-down moderator tank has been performed to identify the potential problems of the flow visualization and measurement in the scaled-down moderator test facility. With a transparent moderator tank model, a velocity field is measured with a Particle Image Velocimetry (PIV) technique under an isothermal state. The flow patterns from the inlet nozzles to the top region of the tank are investigated using PIV for a 1/8 scale moderator tank.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.6
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• pp.1261-1267
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• 2011

Electricity meters using in Korea are about 1.8 million units. From among these, electronic meters for high voltage, about 170 thousand units were installed to the digital type meter and ones for low voltage installed hundreds of thou-sands of meters through a model project. Recently, low voltage meter are expected to complete the installation within several years. Domestic power metering technology is being beyond a simple framework with an electronic type and is rapidly evolving to intelligent smart metering systems in conjunction with promotion of a national smart grid project. Accordingly, it is important to ensure an immunity of meter for electromagnetic field and environmental noise at the installation site. In this paper, we are going to check the validity of international standard that focusing on RF electromagnetic field immunity of meter to secure the quality and improve the reliability in field operation of meter. And we will verify the validity of test specification focused on actual installation environment and are going to offer the improvement plan of test standard.