• Journal of the Korean Electrochemical Society
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• v.20 no.1
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• pp.7-12
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• 2017

Using a precursor of $LiNi_{0.6}Co_{0.2}Mn_{0.2}O_2$ as a starting material, a surface-modified cathode material was obtained by coating with KCl, where the added KCl reduces residual Li compounds such as $Li_2CO_3$ and LiOH, on the surface. The resulting electrochemical properties were investigated. The amounts of $Li_2CO_3$ and LiOH decreased from 8,464 ppm to 1,639 ppm and from 8,088 ppm to 6,287 ppm, respectively, with 1 wt% KCl added $LiNi_{0.6}Co_{0.2}Mn_{0.2}O_2$ that had been calcined at $800^{\circ}C$. X-ray diffraction results revealed that 1 wt% of KCl added $LiNi_{0.6}Co_{0.2}Mn_{0.2}O_2$ did not affect the parent structure but enhanced the development of hexagonal crystallites. Additionally, the charge transfer resistance ($R_{ct}$) decreased dramatically from $225{\Omega}$ to $99{\Omega}$, and the discharge capacity increased to 182.73mAh/g. Using atomic force microscopy, we observed that the surface area decreased by half because of the exothermic heat released by the Li residues. The reduced surface area protects the cathode material from reacting with the electrolyte and hinders the development of a solid electrolyte interphase (SEI) film on the surface of the oxide particles. Finally, we found that the introduction of KCl into $LiNi_{0.6}Co_{0.2}Mn_{0.2}O_2$ is a very effective method of enhancing the electrochemical properties of this active material by reducing the residual Li. To the best of our knowledge, this report is the first to demonstrate this phenomenon.

• Journal of the Korean Institute of Landscape Architecture
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• v.47 no.3
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• pp.31-38
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• 2019

This study quantified, through a direct harvesting method, storage and annual uptake of carbon from open-grown trees for three landscape tree species frequently planted in the southern region of Korea, and developed quantitative models to easily estimate the carbon reduction by tree growth for each species. The tree species for the study included Camellia japonica, Lagerstroemia indica, and Quercus myrsinaefolia, for which no information on carbon storage and uptake was available. Ten tree individuals for each species (a total of 30 individuals) were sampled considering various stem diameter sizes at given intervals. The study measured biomass for each part of the sample trees to quantify the total carbon storage per tree. Annual carbon uptake per tree was computed by analyzing the radial growth rates of the stem samples at breast height or ground level. Quantitative models were developed using stem diameter as an independent variable to easily calculate storage and annual uptake of carbon per tree for study species. All the quantitative models showed high fitness with $r^2$ values of 0.94-0.98. The storage and annual uptake of carbon from a Q. myrsinaefolia tree with dbh of 10 cm were 24.0 kg and 4.5 kg/yr, respectively. A C. japonica tree and L. indica tree with dg of 10 cm stored 11.2 kg and 8.1 kg of carbon and annually sequestered 2.6 kg and 1.2 kg, respectively. The above-mentioned carbon storage equaled the amount of carbon emitted from the gasoline consumption of about 42 L for Q. myrsinaefolia, 20 L for C. japonica, and 14 L for L. indica. A tree with the diameter size of 10 cm annually offset carbon emissions from gasoline use of approximately 8 L for Q. myrsinaefolia, 5 L for C. japonica, and 2 L for L. indica. The study pioneers in quantifying biomass and carbon reduction for the landscape tree species in the southern region despite difficulties in direct cutting and root digging of the planted trees.

• Journal of Pharmaceutical Investigation
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• v.36 no.5
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• pp.331-338
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• 2006

A rapid, selective and sensitive reverse-phase HPLC methods for the determination of atenolol and chlorthalidone in human serum and whole blood were validated, and applied to the pharmacokinetic study of atenolol and chlorthalidone combination therapy. Atenolol and an internal standard, pindolol, were extracted from human serum by liquid-liquid extraction, and analyzed on a $\mu$-Bondapak C18 $10-{\mu}$ column in a mobile phase of methanol-0.01 M potassium dihydrogenphosphate(30:70, v/v, adjusted to pH 3.5) and fluorescence detection(emission: 300 nm, excitation: 224 nm). Chlorthalidone and an internal standard, probenecid, were extracted form human whole blood by liquid-liquid extraction, and analyzed on a Luna C18 $5-{\mu}$ column in a mobile phase of acetonitrile containing 77% 0.01 M sodium acetate and UV detection at 214 nm. These analysis were performed at three different laboratories using the same quality control(QC) samples. The chromatograms showed good resolution, sensitivity, and no interference by human serum and whole blood, respectively. The methods showed linear responses over a concentration range of 10-1,000 ng/mL for atenolol and 0.05-20 ${\mu}g/mL$ for chlorthalidone, with correlation coefficients of greater than 0.999 at all the three laboratories. Intra- and inter-day assay precision and accuracy fulfilled international requirements. Stability studies(freeze-thaw, short-, long-term, extracted sample and stock solution) showed that atenolol and chlorthalidone were stable. The lower limit of quantitation of atenolol and chlorthalidone were 10 ng/mL and 0.05 ${\mu}g/mL$, respectively, which was sensitive enough for pharmacokinetic studies. These methods were applied to the pharmacokinetic study of atenolol and chlorthalidone in human volunteers following a single oral administration of Hyundai $Tenoretic^{\circledR}$ tablet(atenolol 50 mg and chlorthalidone 12.5 mg) at three different laboratories.

• Korean Journal of Remote Sensing
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• v.36 no.5_3
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• pp.1037-1051
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• 2020

The accurate monitoring and forecasting of the intensity of tropical cyclones (TCs) are able to effectively reduce the overall costs of disaster management. In this study, we proposed a multi-task learning (MTL) based deep learning model for real-time TC intensity estimation and forecasting with the lead time of 6-12 hours following the event, based on the fusion of geostationary satellite images and numerical forecast model output. A total of 142 TCs which developed in the Northwest Pacific from 2011 to 2016 were used in this study. The Communications system, the Ocean and Meteorological Satellite (COMS) Meteorological Imager (MI) data were used to extract the images of typhoons, and the Climate Forecast System version 2 (CFSv2) provided by the National Center of Environmental Prediction (NCEP) was employed to extract air and ocean forecasting data. This study suggested two schemes with different input variables to the MTL models. Scheme 1 used only satellite-based input data while scheme 2 used both satellite images and numerical forecast modeling. As a result of real-time TC intensity estimation, Both schemes exhibited similar performance. For TC intensity forecasting with the lead time of 6 and 12 hours, scheme 2 improved the performance by 13% and 16%, respectively, in terms of the root mean squared error (RMSE) when compared to scheme 1. Relative root mean squared errors(rRMSE) for most intensity levels were lessthan 30%. The lower mean absolute error (MAE) and RMSE were found for the lower intensity levels of TCs. In the test results of the typhoon HALONG in 2014, scheme 1 tended to overestimate the intensity by about 20 kts at the early development stage. Scheme 2 slightly reduced the error, resulting in an overestimation by about 5 kts. The MTL models reduced the computational cost about 300% when compared to the single-tasking model, which suggested the feasibility of the rapid production of TC intensity forecasts.

• Journal of Pharmaceutical Investigation
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• v.37 no.4
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• pp.223-227
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• 2007

A rapid, simple and sensitive LC/MS/MS method for the determination of lercanidipine in human serum was validated and applied to the pharmacokinetic study of lercanidipine. Lercanidipine and internal standard, amlodipine, were extracted from human serum by liquid-liquid extraction with hexan-isoamyl alcohol (100: 1, v/v) and analyzed on a $Symmetry^{(R)}$ MS $C_{18}$ column with the mobile phase of acetonitrile-0.2% aqueous formic acid (70: 30, v/v). Using MS/MS with multiple reaction monitoring (MRM) mode, lercanidipine and amlodipine were detected without severe interferences from human serum matrix. Lercanidipine produced a protonated precursor ion ($[M+H]^+$) at m/z 612.3 and a corresponding product ion at m/z 280.0. Internal standard produced a protonated precursor ion ($[M+H]^+$]) at m/z 409.0 and a corresponding product ion at m/z 238.0. The ruggedness of this method was investigated using quality control (QC) samples. This method showed linear response over the concentration range of 0.05-20 ng/mL with correlation coefficient greater than 0.999. The lower limit of quantitation using 0.5 mL of serum was 0.05 ng/mL, which was sensitive enough for pharmacokinetic studies. The overall accuracy of the developed method ranged from 85.51 to 112.2% for lercanidipine with overall precision (% C.V.) being 3.56-13.1%. This method showed good ruggedness (within 15% C.V.) and was successfully applied for the analysis of lercanidipine in human serum samples for the pharmacokinetic studies, demonstrating the suitability of the method.

• Journal of Food Hygiene and Safety
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• v.35 no.3
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• pp.225-233
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• 2020

By the standards and specifications for hygiene products, three test methods for formaldehyde are specified for each item type of hygiene product. After derivatization using acetylacetone and 2,4-dinitrophenylhydrazine (2,4-DNPH), formaldehyde is analyzed by spectrophotometer and high-performance liquid chromatography (HPLC). Validation of the three test methods was performed on tissue, diaper lining and waterproof layer, and panty liner products. The results of linearity (R²), limit of detection (LOD), limit of quantification (LOQ), recovery rate (%) and reproducibility (%), showed that all three methods are suitable for analyzing formaldehyde in hygiene products. After derivatization with 2,4-DNPH and cetylacetone, formaldehyde was analyzed at 0, 3, 6, 9, 24 and 48 hours by HPLC. Formaldehyde derivatized with 2,4-DNPH showed no statistically significant change in formaldehyde peak area over time (P>0.05). But, acetylacetone-derivatizated formaldehyde showed a negative correlation coefficient (r) over time (P<0.01). We investigated the residual amounts of formaldehyde in 205 hygiene products distributed in Busan. Among 74 disposable diaper products tested, 73 had low concentrations of formaldehyde (0.13-29.87 mg/kg). Moreover, formaldehyde was not detected in any of 78 tissue, 27 disposable paper towel, 12 disposable dishcloth, 7 paper cup, one brand of paper straw and 6 disposable napkin products.

• Journal of Society of Preventive Korean Medicine
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• v.16 no.2
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• pp.1-15
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• 2012

Objectives : The aim of this study is to analyze satisfaction with clinical training in the department of oriental rehabilitation medicine and the related factors. Methods : All the students in the graduating class of school of Korean Medicine, Pusan National University must be trained for 2 weeks in the department of oriental rehabilitation medicine according to clinical training guideline including Objective Structured Clinical Examination(OSCE) and Clinical Performance Examination (CPX). After completing clinical training, we distributed questionaries to them about a reflex of the object of study, usefulness, difficulty, satisfaction and preference. And then, we analyzed the related factors including descriptive statistics, frequency analysis and correlation analysis by SPSS 18.0. Results : In general, a reflex of the aim of study($7.88{\pm}1.31$), satisfaction with contents($8.17{\pm}1.20$) and difficulty($5.53{\pm}0.99$) were evaluated respectively. The better a reflex of the aim of study is, the higher satisfaction with contents is(P<0.01, r=0.836). Chuna was highly estimated, whereas pharmacopuncture was not. In OSCE, a reflex of the aim of study($8.07{\pm}1.07$) and usefulness($8.13{\pm}1.16$) were highly evaluated. The preference for physical examination of the lumbar spine was highly estimated, whereas applying splint was not. Facilities and equipment($7.88{\pm}1.11$), contents of clinical training($7.25{\pm}1.79$), the handout($7.00{\pm}1.59$) and time scheduling($5.48{\pm}1.71$) were evaluated respectively in general composition of clinical training. There is no difference related to specialty, sex and age among students. Conclusions : Clinical training program in the department of oriental rehabilitation medicine can be highly estimated from the viewpoint of difficulty and satisfaction.

• Parasites, Hosts and Diseases
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• v.53 no.1
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• pp.135-139
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• 2015

A total of 1,708 small mammals (1,617 rodents and 91 soricomorphs), including Apodemus agrarius (n = 1,400), Microtus fortis (167), Crocidura lasiura (91), Mus musculus (32), Myodes (= Eothenomys) regulus (9), Micromys minutus (6), and Tscherskia (= Cricetulus) triton (3), were live-trapped at US/Republic of Korea (ROK) military training sites near the demilitarized zone (DMZ) of Paju, Pocheon, and Yeoncheon, Gyeonggi Province from December 2004 to December 2009. Small mammals were examined for their intestinal nematodes by necropsy. A total of 1,617 rodents (100%) and 91 (100%) soricomorphs were infected with at least 1 nematode species, including Nippostrongylus brasiliensis, Heligmosomoides polygyrus, Syphacia obvelata, Heterakis spumosa, Protospirura muris, Capillaria spp., Trichuris muris, Rictularia affinis, and an unidentified species. N. brasiliensis was the most common species infecting small mammals (1,060; 62.1%) followed by H. polygyrus (617; 36.1%), S. obvelata (370; 21.7%), H. spumosa (314; 18.4%), P. muris (123; 7.2%), and Capillaria spp. (59; 3.5%). Low infection rates (0.1-0.8%) were observed for T. muris, R. affinis, and an unidentified species. The number of recovered worms was highest for N. brasiliensis (21,623 worms; mean 20.4 worms/infected specimen) followed by S. obvelata (9,235; 25.0 worms), H. polygyrus (4,122; 6.7 worms), and H. spumosa (1,160; 3.7 worms). A. agrarius demonstrated the highest prevalence for N. brasiliensis (70.9%), followed by M. minutus (50.0%), T. triton (33.3%), M. fortis (28.1%), M. musculus (15.6%), C. lasiura (13.2%), and M. regulus (0%). This is the first report of nematode infections in small mammals captured near the DMZ in ROK.

• Journal of Food Hygiene and Safety
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• v.36 no.1
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• pp.34-41
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• 2021

The purpose of this research is to improve analysis methods of determining the contents of fatty acids in infant formulas and follow-up formulas. A gas chromatography (GC) method was performed on a GC system coupled to flame ionization detector, with a fused silica capillary column (SP2560, 100 m×0.25 mm, 0.20 ㎛). The method was validated using standard reference material (SRM, NIST 1849a). Performance parameters for method validation such as specificity, linearity, limits of detection (LOD) and quantification (LOQ), accuracy and precision were examined. The linearity of standard solution with correlation coefficient was higher than 0.999 in the range of 0.1-5 mg/mL. The LOD and LOQ were 0.01-0.06 mg/mL and 0.03-0.2 mg/mL, respectively. The recovery using standard reference material was confirmed and the precision was found to be between 0.8% and 2.9% relative standard deviation (RSD). Optimized methods were applied in sample analysis to verify the reliability. All the tested products had acceptable contents of fatty acids compared with component specification for nutrition labeling. The result of this research will provide efficient experimental information and strengthen the management of nutrients in infant formula and follow-up formula.

• Korean Journal of Environmental Agriculture
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• v.42 no.1
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• pp.71-81
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• 2023

An accurate and easy-to-use analytical method for determining isocycloseram and its metabolites (SYN549431 and SYN548569) residue is necessary in various food matrixes. Additionally, this method should satisfy domestic and international guidelines (Ministry of Food and Drug Safety and Codex Alimentarius Commission CAC/GL 40). Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) was used to determine the isocycloseram and its metabolites residue in foods. To determine the residue and its metabolites, a sample was extracted with 20 mL of 0.1% formic acid in acetonitrile, 4 g magnesium sulfate anhydrous and 1 g sodium chloride and centrifuged (4,700 G, 10 min, 4℃). To remove the interferences and moisture, d-SPE cartridge was performed before LC-MS/MS analysis with C₁₈ column. To verify the method, a total of five agricultural commodities (hulled rice, potato, soybean, mandarin, and red pepper) were used as a representative group. The matrix-matched calibration curves were confirmed with coefficients of determination (R²) ≥ 0.99 at a calibration range of 0.001-0.05 mg/kg. The limits of detection and quantification were 0.003 and 0.01 mg/kg, respectively. Mean average recoveries were 71.5-109.8% and precision was less than 10% for all five samples. In addition, inter-laboratory validation testing revealed that average recovery was 75.4-107.0% and the coefficient of variation (CV) was below 19.4%. The method is suitable for MFDS, CODEX, and EU guideline for residue analysis. Thus, this method can be useful for determining the residue in various food matrixes in routine analysis.