• 한국초전도학회:학술대회논문집
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• v.15
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• pp.40-40
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• 2005

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.2
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• pp.187-193
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• 2004

For a power source of usual electronic devices such as PDA, smart phone, UPS and electric vehicle, the battery made of serially connected multiple cells is generally used. In this case, if there are some unbalanced among cell voltages, the total lifetime and the total capacity of the battery are limited to a lower value. To maintain a balanced condition in cells, an effective method of regulating the cell voltage in indispensable. In this paper, we propose the design of a balancing circuit for electronic appliances. The balancing system was controlled by a micro-controller which enables to implement the balancing action during charging period. Proposed method has been verified by the experiment using the charger and recorder. The experimental results show that the individual battery equalization can improve battery capacity and battery lifetime and performance through an extended operational time.

• Proceedings of the KIPE Conference
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• 2019.11a
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• pp.70-72
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• 2019

For the safe and reliable operation of Lithium-ion batteries in Electric Vehicles (EVs) or Energy Storage Systems (ESSs), it is essential to have accurate information of the battery such as State of Charge (SOC). Many kinds of different techniques to estimate the SOC of the batteries have been developed so far such as the Kalman Filter. However, when it is applied to the multiple number of batteries it is difficult to maintain the accuracy of the estimation over all cells due to the difference in parameter value of each cell. Moreover the difference in the parameter of each cell may become larger as the operation time accumulates due to aging. In this paper a novel Deep Neural Network (DNN) based SOC estimation method for multi cell application is proposed. In the proposed method DNN is implemented to learn non-linear relationship of the voltage and current of the lithium-ion battery at different SOCs and different temperatures. In the training the voltage and current data of the Lithium battery at charge and discharge cycles obtained at different temperatures are used. After the comprehensive training with the data obtained with a cell resulting estimation algorithm is applied to the other cells. The experimental results show that the Mean Absolute Error (MAE) of the estimation is 0.56% at 25℃, and 3.16% at 60℃ with the proposed SOC estimation algorithm.

• Journal of Korean Society on Water Environment
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• v.27 no.4
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• pp.486-490
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• 2011

As(V) adsorption on aluminum oxide powder which was recycled from industrial wastes containing aluminum hydroxide was evaluated. Aluminum oxide powder in this study was prepared by calcinating aluminum hydroxide wastes at$550^{\circ}C$. Spectroscopic analysis indicated that the aluminum hydroxide wastes were changed to aluminum oxide by calcination. Arsenic adsorption isotherm was conducted with variation of ionic strength and multiple-ion systems using Ca(II) and Cu(II). As(V) removal showed typical anionic adsorption characteristics that the removal efficiency decreased with increasing pH in single As(V) system as well as in binary and ternary system. More than 80% of As(V) at an initial concentration of $5{\times}10^{-5}$ M was removed from aluminum oxide powder in As(V) single system. The effect of ionic strength on As(V) adsorption was negligible, which indicated the strong bonding between aluminum oxide powder and As(V). The removal efficiency of As(V) was higher in a binary system with Cu(II) than in a binary system with Ca(II).

• Journal of Korean Society of Water Science and Technology
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• v.26 no.6
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• pp.13-26
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• 2018

This research was conducted to elucidate the removal mechanism of heavy metals and sulfate ion from acid mine drainage(AMD) by porous zeolite-slag ceramics (ZS ceramics) packed in a column reactor system. The average removal efficiencies of heavy metals and sulfate ion from AMD by the 1:3(Z:S) porous ZS ceramics in the column reactor under the HRT condition of 24 hours were Al 97.5%, As 98.8%, Cd 86.1%, Cu 96.2%, Fe 99.7%, Mn 64.1%, Pb 97.2%, Zn 66.7%, and $SO_4{^{2-}}$ 76.0% during 121 days of operation time. The XRD analysis showed that the ferric iron from AMD could be removed by adsorption and/or ion-exchange on the porous ZS ceramics. In addition it was known that Al, As, Cu, Mn, and Zn could adsorb or coprecipitate on the surface of Fe precipitates such as schwertmannite, ferrihydrite, or goethite. The EDS analysis revealed that Al, Fe, and Mn, which were of relatively high concentration in the AMD, would be adsorbed and/or ion-exchanged on the porous ZS ceramics and also exhibited that Al, Cu, Fe, Mn, and Zn could be precipitated as the form of metal hydroxide or sulfate and adsorbed or coprecipitated on the surface of Fe precipitates. The microscopic results on the porous ZS ceramics and precipitated sludge in a column reactor system suggested that the heavy metals and sulfate ion from AMD would be eliminated by the multiple mechanisms of coprecipitation, adsorption, ion-exchange as well as precipitation.

• Analytical Science and Technology
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• v.15 no.5
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• pp.410-416
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• 2002

In this study, a new quantitative analytical method has been developed for the rapid determination of vancomycin in human plasma and urine using liquid chromatography/tandem mass spectrometry (LC - MS/MS). Chromatography was carried out on a $C_{18}$ XTerra MS column ($2.1{\times}30mm$) with a particle size of $3.5{\mu}m$. The mobile phase was 0.25% formic acid in 10% acetonitrile and the flow rate was $250{\mu}L/min$. Vancomycin and caffeine (internal standard) were detected by MS/MS using multiple reaction monitoring (MRM). Vancomycin gives a predominant doubly protonated precursor molecule ($[M+2H]^{2+}$) at m/z 725.0 and a corresponding product ion of m/z 100.0. Detection of vancomycin was good, accurate and precise, with a limit of detection of 1 nM in plasma. The calibration curves for vancomycin in human plasma was linear in a concentration range of $0.01{\mu}M$ - $100{\mu}M$ for plasma. This method has been successfully applied to determine the concentration of vancomycin in human plasma and urine from pharmacokinetic study and relative studies.

• Analytical Science and Technology
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• v.24 no.6
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• pp.533-543
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• 2011

The hERG (human ether-a-go-go related gene) ion channel is a main factor for cardiac repolarization, and the blockade of this channel could induce arrhythmia and sudden death. Therefore, potential hERG ion channel inhibitors are now a primary concern in the drug discovery process, and lots of efforts are focused on the minimizing the cardiotoxic side effect. In this study, $IC_{50}$ data of 202 organic compounds in HEK (human embryonic kidney) cell from literatures were used to develop predictive 2D-QSAR model. Multiple linear regression (MLR), Support Vector Machine (SVM), and artificial neural network (ANN) were utilized to predict inhibition concentration of hERG ion channel as machine learning methods. Population based-forward selection method with cross-validation procedure was combined with each learning method and used to select best subset descriptors for each learning algorithm. The best model was ANN model based on 14 descriptors ($R^2_{CV}$=0.617, RMSECV=0.762, MAECV=0.583) and the MLR model could describe the structural characteristics of inhibitors and interaction with hERG receptors. The validation of QSAR models was evaluated through the 5-fold cross-validation and Y-scrambling test.

• Analytical Science and Technology
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• v.20 no.4
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• pp.331-338
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• 2007

Licorice, Glycyrrhizae Radix is widely used as a herbal medicines and a dietary supplements in East Asia. We employed high performance liquid chromatography electrospray ionization tandem mass spectrometry to determine liquiritin and glycyrrhizin in the Glycyrrhizae Radix. Liquiritin and glycyrrhizin in Glycyrrhizae Radix were ionized by positive ion pneumatically assisted electrospray and detected by HPLC-MS/MS in the multiple-reaction monitoring (MRM) mode using precursor ${\rightarrow}$ product ion combinations at m/z $436.2{\rightarrow}257.0$ and $823.4{\rightarrow}453.4$, respectively. The assay had a calibration range from 10 to 3,000 ng/mL. The limits of detection (LOD) of the liquiritin and glycyrrhizin were 0.4 ng/mL and 0.01 ng/mL, respectively. The reproducibility and repeatability (relative standard deviation) at different analyte concentrations varied from 103 to 113 % and 0.95 to 1.8 %, respectively. According to the above results, HPLC-MS/MS method permits assignment of tentative structures such as liquiritin and glycyrrhizin in the Glycyrrhizae Radix.

• Mass Spectrometry Letters
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• v.3 no.3
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• pp.82-85
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• 2012

The formation of zinc finger peptide-$Zn^{2+}$ complexes in electrospray ionization mass spectrometry (ESI-MS) was examined using three different metal ion sources: $ZnCl_2$, $Zn(CH_3COO)_2$, and $Zn(OOC(CHOH)_2COO)$. For the four zinc finger peptides (Sp1-1, Sp1-3, CF2II-4, and CF2II-6) that bind only a single $Zn^{2+}$ in the native condition, electrospray of apo-zinc finger in solution containing $ZnCl_2$ or $Zn(CH_3COO)_2$ resulted in the formation of zinc finger-$Zn^{2+}$ complexes with multiple zinc ions. This result suggests the formation of nonspecific zinc finger-$Zn^{2+}$ complexes. Zn(tartrate), $Zn(OOC(CHOH)_2COO)$, mainly produced specific zinc finger-$Zn^{2+}$ complexes with a single zinc ion. This study clearly indicates that tartrate is an excellent counter ion in ESI-MS studies of zinc finger-$Zn^{2+}$ complexes, which prevents the formation of nonspecific zinc finger-$Zn^{2+}$ complexes.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.2
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• pp.66-73
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• 2017

This study was to evaluate the influential parameters such as intial Cs concentration, reaction temperature, contact time and pH variation of solution on Cs adsorption. Using the experimental data, adsorption kinetics, isotherms and thermodynamic properties were analyzed. The Cs ion adsorption of the zeolite X was effective in the range from pH 5 to 10 and reached equilibrium after 60 minutes. The adsorption kinetics and isotherms of Cs ion with the zeolite X was described well by the pseudo-second-order kinetic and Langmuir isotherm model. The maximum adsorption capacities of Cs ion calculated from Langmuir isotherm model at 293~333 K were from 303.03 mg/g to 333.33 mg/g. It was found that thermodynamic property of Cs ion absorption on the zeolite X was spontaneous and endothermic reaction. The experimental data were fitted a second-order polynomial equation by the multiple regression analysis. The values of the dependent variable calculated by this best fitted model equation were in very good agreement with the experimentally obtained values.