• Journal of the Korean GEO-environmental Society
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• v.12 no.10
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• pp.39-49
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• 2011

Recently PBD method, one of acceleration of consolidation methods is used in the soft ground to shorten consolidation time for fast settlement during construction. It is economical and easy to work. Discharge capacity of PBD is sensitive in proportion to thickness of soft ground layer, and drainage of PBD declines due to disturbance effect in surrounding ground by mandrel used for vertical drainage setting and setting machines and type. Also, deviation of discharge capacity is large according to ground condition, construction condition and soil properties. In addition, when embankment loading is not conducted instantly after PBD setting due to rain or lack of embankment material supply, it causes leaving period problems. But cause and analysis of those problems for discharge capacity is lack. So, in this test, ground improvement and discharge capacity is investigated by implementing composite discharge capacity test for analysis of an effect factor of PBD discharge capacity with leaving period. After fixing the vertical drain on a cylindrical cylinder, put churned sample into the cylinder. Then leave 0day, 30day, 60day and 90day. And then, load following the loading step of 30, 70 and 120kPa using a pressure device. As a result, the longer leaving period, discharge capacity is reduced. It is caused by a decrease of discharge area caused by creep transformation moisture absorption of PBD filter after long leaving period.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.7
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• pp.636-643
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• 2006

Si-C materials were synthesized by the heating the mixture of silicon and polyvinylidene fluoride (PVDF). The electrochemical properties of the Si-C materials as the high capacitive anode materials of lithium secondary batteries were evaluated by the galvanostatic charge-discharge test through 2032 type $Si-C{\mid}Li$ coin cells. Charge-discharge tests were performed at C/10 hour rate(C = 372 mAh/g). Initial discharge and charge capacities of $Si-C{\mid}Li$ cell using a Si-C material derived from PVDF(20wt.%) were found to be 1,830 and 526 mAh/g respectively. The initial discharge-charge characteristics of the developed Si-C electrode were analyzed by the electrochemical galvanostatic test adopting the capacity limited charge cut-off condition(GISOC). The range of reversible specific capacity IIE(intercalation efficiency at initial discharge-charge) and IICs(surface irreversible specific capacity) were 216 mAh/g, 68 % and 31 mAh/g, respectively.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.2
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• pp.69-75
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• 2005

In order to improve the reliability of high voltage rotating machines and mold transformers, it is necessary to understand the breakdown mechanism and life assessment of the high voltage winding parts. Especially the on-line PD test provides the ability to monitor effects, such as slot discharge, internal discharge, and end-winding discharge without interrupting the electrical machines, this method has been proven the major testing technology. Capacitive couplers have been the most widely used sensors for the on-line partial discharge detection in rotating machines nowadays. This paper deals with the electrical characteristics and long-term reliability of a ceramic coupler(CC), which can be easily mounted into high voltage input terminal part, has been developed and tested to continuously measure PD activity during operating condition. This paper presents electrical characteristics (dielectric loss angle, capacitance, PD inception level, breakdown voltage, and frequency response bandwidth) and long-term life test result of the developed 6.6 kV class on-line ceramic coupling sensor. It was found that this sensor had good electrical characteristics to detect PD activity during the operating condition with its detection frequency band is between several and several tens MHz. Also, the voltage life of the 6.6kV class ceramic coupler was calculated over 60 years.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.7
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• pp.16-22
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• 2012

With the increase of consumption of new renewable energy, the use of Electric Double Layer Capacitor(EDLC) is being gradually widened as the next generation energy storage device. In order to expand the market of EDLC which is recently receiving a lot of attraction as a new promising area, development of a charge/discharge cycle tester to measure and test performance, is essential. Therefore, this research designed a circuit to measure capacity and internal resistance and a circuit to measure voltage maintenance properties, based on EDLC's basic charging/discharging properties so it is able to measure the state of charge and discharge at high speed. When evaluating performance characteristics, the 5[V]/100[A] prototype-EDLC charge/discharge testing system developed for this research showed ${\pm}0.1$[%] of accuracy of voltage and current measurement. It was also proved that the developed charge/discharge testing system for EDLC can be applied to the actual industry, when testing the entire system using a program produced for data monitoring and acquisition.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.142-144
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• 2005

To detect partial discharge of 154kV joint box, we have made experiment by using the Al-foil electrode sensor. Generally the signals which are detected in partial discharge test of underground power transmission cable are accompanied wi th both noises of high voltage and noises of surrounding power cable. The most noise in near to end part of joint box is corona, beside other noises flowed from surrounding area. Partial discharge test is difficulty due to these noises. First, we had used Al-Foi1 sensor on middle joint box of 154[kV] underground transmission power cable, and then analyzed reliability of calibration signal by using the Al-Foi1 electrode sensor of NJB. From above results, decrement properties measured highly. But incase of injecting calibration signal of 500[pC] after measuring signals in IJB, the S/N ratio had about 25[dB] acquisition.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.1 s.232
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• pp.151-158
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• 2005

A characteristic of discharge for a foam spray nozzle with various parameters was investigated. The discharge patterns from a fire foam spray nozzle are important to evenly spray over a maximum possible floor area. Two parameters of a foam spray nozzle were chosen, and compared with those from the standard one. Also, in order to evaluate the performance of discharged foam agents used to protect structures from heat and fire damages, the thermal characteristics of fire-protection foams were experimentally investigated. A simple repeatable test for fire-protection foams subjected to fire radiation was developed. This test involves foam generation equipment, a fire source for heat generation, and data acquisition techniques. Results show that the bubble size of foam is increased by large inside diameter of orifice or closed air hole, but phenomenon of discharge angle and expansion ratio is opposite. For the case of the open air hole, liquid film of a circular cone discharges with formation, growth, split and fine grain. In case of the closed air hole, a pillar of foam solution discharges with that. Though the temperature gradient in the foam increases with increased foam expansion ratio. it is not change with increased intensity of heat flux.

• Child Health Nursing Research
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• v.30 no.2
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• pp.118-128
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• 2024

Purpose: This study aimed to examine the health concerns of parents regarding their premature infants and to identify changes in these concerns during perinatal period and after discharge. Methods: This was a retrospective study performed at a single tertiary center that enrolled 119 premature infants who were discharged from the neonatal intensive care unit (NICU) and visited the outpatient pediatrics department between December 2018 and October 2021. Data on the concerns of 176 parents regarding enrolled premature infants' health from before birth to 1 week after NICU discharge were obtained from outpatient records. The t test and with the chi-squared test were used to analyze the data for this study. Results: The consistently greatest focus of parents' health concerns was the respiratory system. The second focus of parents' health concerns before discharge was the central nervous system. However, during the first week after NICU discharge, the gastrointestinal system was the second-most frequent focus of parents' health concerns among parents of infants without diseases related to prematurity and infants with older gestational ages. Conclusion: The results of this study offer insights into the health concerns among parents of premature infants. Parental health concerns about premature infants vary over time, from before birth to post-discharge, necessitating supportive interventions to enhance parental understanding of their child's health status.

• Journal of Korean Academy of Nursing
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• v.21 no.3
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• pp.257-267
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• 1991

This study investigated the effects of nursing in formation given verbally and a booklet on the knowledge, Physical symptoms, anxiety and daily activities of patients recovering from open heart surgery from just before discharge to six weeks after discharge. The convenience sample was of patients who had undergone open heart surgery in Seoul National University Hospital. The first 25 patients who agreed to participate in the study became the control group. They did not receive the intentional information but the usual nursing care. The next 28 patients became the experimental group who received a booklet about their post-discharge care which was discussed with them by the researcher before discharge. This study used a non equivalent control group non - synchronized quasiexperimental design. The tools included a 30 item knowledge scale, a 9 item physical symptom scale, Spielberger's state anxiety scale, and a 28 item daily activity scale. The instruments were applied before discharge and at two and six weeks after discharge. For data analysis, frequency, t-test, Pearson's Correlational Coefficient and Cronbach's $\alpha$ were used. The results were as follows : 1. Information given through the booklet was effective in increasing the knowledge of patients recovering from open heart surgery. The experimental group's knowledge was higher at 2 weeks after discharge than prior to discharge (P＜0.05). 2. There was no significant difference in physical symptoms between the two groups at two and six weeks after discharge. 3. Information given through the booklet was effective in decreasing the State Anxiety two weeks after discharge (P＜0.001) but at six weeks after discharge, there was no significant difference in anxiety between the control and the experimental groups. 4. There was no significant difference in daily activity between the two groups at two and six weeks after discharge. 5. There was a negative correlation between knowledge at discharge and at 2 weeks and anxiety at 2 weeks after discharge. There was a positive correlation between knowledge at discharge and daily activity at 2 weeks after discharge. There was a negative correlation between knowledge at 2 weeks and Physical symptom at 6 weeks after discharge.

• Journal of the Korean Society of Safety
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• v.29 no.6
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• pp.46-48
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• 2014

This paper compared and demonstrated the performance of the earth plate for conventional type and early streamer discharging type developed a new plate in order to improve the performance of the ground plate for use in grounding. The results obtained are shown below; early streamer discharge earth plate was high 5 kV on DC flashover voltage and corona discharge current was higher than about 2 times under the same test conditions compared to the conventional earth plate. From the experiential result, streamer discharge earth plate had a function of rapid inflow/out flow than the general ground plane because of by corona discharge current to be generated in the sharp serrated in formed the ground plane when strike current occurred. In the future, the newly developed early streamer discharge ground plate would be beneficial for grounding work to be widely used to promote the convenience and economy of construction.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.2
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• pp.65-71
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• 2001

This paper describes partial discharge phenomenon with SF6gas pressures in insulation consisting of insulation paper and SF6 gas. We made the specimens with SF6 gas gaps which exist between aramid papers and electrodes and calculated the electric field intensity in the these gaps. We measured the partial discharge inception voltages and the AC breakdown voltages with the test method of IEC 60060-2 and did the partial discharge degradation experiments with a constant voltage. According to gas pressures, the breakdown voltages in SF6gas gaps were calculated by Paschen's law. And these results showed the ability applying partial discharge inception voltages evaluation to Paschen's law and the relationship between the PD quantities occurring insulation breakdown and PD occurring area.