• Bulletin of the Korean Chemical Society
• /
• v.23 no.8
• /
• pp.1144-1148
• /
• 2002

We prepared the polyaniline (Pani) film and powder by chemical polymerization and doping with different dopants and also investigated the capability of Li//polyaniline cells after assembling. The oxidation/reduction potentials and electrochemical reaction of Li//polyaniline cells were tested by cyclic voltammetry technique. The Li//Pani-HCl cells with 10% and 20% conductors show a little larger specific discharge capacities than that without conductor. The highest discharge capacity of almost 50 mAh/g at 100th cycle is also achieved. However, Li//Pani-LiPF6 with 20% conductor shows a remarkable performance of ~90 mAh/g at 100th cycle. This is feasible value for using as the positive electrode material of lithium ion secondary batteries. It is also proved that the powder type electrode of Pani is better to use than the film type one to improve the specific discharge capacity and its stability with cycle.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.63 no.2
• /
• pp.266-271
• /
• 2014

The Electromagnetic Interference(EMI) generating from corona discharge of transformer area can interference the digital Instrument and Control(I&C) systems located nearby transformers. When the potential gradient of the electric field around the conductor is high enough to form a conductive region but not high enough to cause electrical breakdown to nearby objects, the EMI of corona discharge emits with the conducted and radiated noise and it interferences the signals of the I&C systems. Since digital I&C systems have an efficiency and competitive price, the analog I&C systems have been upgraded and displaced with the digital I&C systems but which have less EMI Immunity. There was no assessment to I&C systems by EMI generating corona discharge nearby transformers. When the safety-related I&C systems are installed in plants, the verification of equipment EMI should be done not in site-specific test but in test facilities. There are the need to do the site-specific EMI evaluation of corona discharge nearby transformers. This paper assesses the margin between plant emission limits and the highest composite plant emission of corona. When the non safety-related I&C systems are placed in transformer area, it suggests the appropriate radiated susceptibility level to EMI of corona discharge.

• Korean Journal of Materials Research
• /
• v.29 no.12
• /
• pp.798-803
• /
• 2019

The self-discharge behavior of zinc-air batteries is a critical issue induced by corrosion and hydrogen evolution reaction (HER) of zinc anode. The corrosion reaction and HER can be controlled by a gelling agent and concentration of potassium hydroxide (KOH) solution. Various concentrations of KOH solution and polyacrylic acid have been used for gel electrolyte. The electrolyte solution is prepared with different concentrations of KOH (6 M, 7 M, 8 M, 9 M). Among studied materials, the cell assembled with 6 M KOH gel electrolyte exhibits the highest specific discharge capacity and poor capacity retention. Whereas, 9 M KOH gel electrolyte shows high capacity retention. However, a large amount of hydrogen gas is evolved with 9 M KOH solution. In general, the increase in concentration is related to ionic conductivity. At concentrations above 7 M, the viscosity increases and the conductivity decreases. As a result, compared to other studied materials, 7 M KOH gel electrolyte is suitable for Zn-air batteries because of its higher capacity retention (92.00 %) and specific discharge capacity (351.80 mAh/g) after 6 hr storage.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2000.04a
• /
• pp.91-98
• /
• 2000

Derivation of stage-discharge relationship and characteristics for Yangsan river is presented in this paper. This research has been conducted as the second one after the first trial of 1997. The determination of discharge at a Yangsan river gauging was best made by measuring the flow velocities with a current meter and rod float. The rating curve obtained through 52 stage-discharge measurements on Yangsan river basin in 1999 is represented by Q=15.3540-140.6076H+182.44372$H^2$, which is discovered to be most excellent among other curves in reliability analysis. The capability of the observed stage-discharge data for Yangsan river was tested by HEC-RAS program, and its capability to reproduce discharge was investigated and compared with the computational results. Rating curve stability is determined on the basis of deviations in the stage-discharge relationship, utilization of specific gauge, and absolute differences between sequential stream flow measurements and an analysis residuals. Therefore it seems necessary to research method to obtain rating curve in a rigorous and accurate manner.

• Journal of Korean Academy of Nursing
• /
• v.12 no.2
• /
• pp.31-44
• /
• 1982

The purpose of this study was to analyze the relationship between maternal attachment and discharge against advice in high risk infants and determine the factors which affect discharge against advice. Data of this study were collected by means of reviewing the medical records of 127 in-patients who were diagnosed as high risk infants in admission and interviewing of the mothers of these patients was done by telephone. The high risk categories were neonatal hyperbilirubinemia, congenital anomaly, congenital heart disease, blood disorder, neonatal infection and birth injury. Maternal attachment was measured by deviding the subjects into 2 groups, the one the continuing treatment group and the other the discharge against advice group. Maternal attachment is determined by an interplay of maternal attitude and specific infant behaviors. Maternal attachment developes through continuous physical and psychological contact between mother and infants. Later it developes into maternal love. The results were as follows: 1. There was a significant association between maternal attachment and discharge against advice, that is, the attachment score was higher in the continuing treatment group. 2. Inspite of controlling medical insurance, severity of disease and the length of stay, it was found that there continued to be either a partially significant or fully significant relationship between maternal attachment and discharge against advice. Stepwise multiple regression revealed that maternal attachment was second in importance as a predictor of discharge against advice, which indicates that maternal attachment was a significant predictor of discharge against advice. 3. Stepwise multiple regression revealed that in 32.3％ of these cases the significant predictors of discharge against advice were length of stay, maternal attachment, delivery type, feeding type and income.

• Proceedings of the Safety Management and Science Conference
• /
• 2003.11a
• /
• pp.343-350
• /
• 2003

The best Ppy weight ratio was 7 wt% and the optimal electrode composition ratio was 78 : 17 : 5 wt.% of (MSP-20 : BP-20 =1 : 1), (Super P : Ppy =10 : 7) and P(VdF-co-HFP). Implantation of Ppy as the conducting agents have led to superior electrochemical characteristics because of the low of internal resistance and faradaic capacitance. The result of unit cell with Ppy 7 wt% were as follows: 28.02 Fig of specific capacitance, 1.34 Ω of DC-ESR and 0.36 Ω of AC-ESR. Unit cell showed a good stability up to 200 charge-discharge cycles, retaining 82% of their original capacity at 200 cycles. From the analysis of impedance, the electrodes with Ppy 7 wt% showed low ESR, low charge transfer resistance and quick reaction rate. It was inferred that quick charge-discharge was possible. As compared with the specific capacitance (rectangular shape) of CV, it was also concluded that the specific capacitance originated from thecompound phenomena of the faradaic capacitance by oxidation and reduction of Ppy and the non-faradaic capacitance by adsorption-desorption of activated carbon.

• Journal of the Korean Electrochemical Society
• /
• v.4 no.3
• /
• pp.113-117
• /
• 2001

Specific capacitance and charge-discharge rate of EDLC using activated carbon electrode were affected by the compositions of electrolytes, the conditions of charge-discharge and physical properties of activated carbon materials. The activated carbon electrode was prepared by dip coating method. Charge-discharge test and electrochemical experiments were carried out for various kinds of organic electrolytes. Effects of charge and discharge current density on the specific capacitance were studied. Characteristics of leakage current, self-discharge and time-voltage curves in optimum conditions of organic electrolytes were compared with conventional $1M-Et_4NBF_4/PC$ electrolyte. The EDLC using MSP-20(specific surface area: $2000m^2/g$) electrode and $1M-LiPF_6/PC-DEC(1:1)$ was exhibited th highest specific capacitance of 130F/g and low polarization resistances. The EDLC using MSP-20 electrode at $1M-LiPF_6/PC-DEC(1:1)$ was small leak current of 0.0004A for 15min, long voltage retention of 0.8V after 100h and linear time-voltage curves with small IR-drop.

• Clinical and Experimental Pediatrics
• /
• v.53 no.10
• /
• pp.917-920
• /
• 2010

Although milky nipple discharge appears frequently in infants, bloody nipple discharge is a very rare finding. We experienced a 4-month-old, breast-fed infant who showed bilateral bloody nipple discharge with no signs of infection, engorgement, or hypertrophy. The infant's hormonal examination and coagulation tests were normal, and an ultrasound examination revealed mammary duct ectasia. The symptoms resolved spontaneously within 6 weeks without any specific treatment, except that we advised the mother to refrain from taking herbal medicine. Since no such case has been previously reported in Korea, we present this case with a brief review of the literature.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.64 no.5
• /
• pp.732-738
• /
• 2015

In ac discharge, emission efficiency shows an time-varying characteristics during discharge. The phenomenon is caused by the potential distribution changes during the discharge, which indicates that a specific potential distribution can contribute to a high improvement of the emission efficiency. To create an artificial environment for a potential distribution favorable to emission efficiency, we used the asymmetric electrode structure and proved the capability. Our results showed that the ratio of the area of anode to cathode became larger, the emission efficacy was greatly improved.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2023.05a
• /
• pp.39-39
• /
• 2023

Nonlinear weirs, such as labyrinth and piano key weirs, are suitable methods to handle increased flood flows that may be expected due to climate change. Although specific physical models are considered to be an effective way of investigating fluid flows, simply conducting physical model tests is insufficient to fully comprehend the hydraulic and discharge characteristics of non-linear weirs. In this study, computational fluid dynamics algorithms have been used extensively to investigate complex flow physics instead of relying on reduced scale models. The discharge capacity of the piano key weir and the rectangular labyrinth weir is compared using a three-dimensional numerical model, which is validated by the available experimental data. The results confirm that piano key weir is more efficient than the rectangular labyrinth weir for a wide range of head water ratios. By analyzing the contribution of discharge over inlet, outlet and sidewall crests, the factor that make the piano key weir superior to the rectangular weir is the sidewall discharge.