• Ceramist
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• v.21 no.4
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• pp.312-330
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• 2018

Energy storage/conversion has become crucial not only to meet the present energy demand but also more importantly to sustain the modern society. Particularly, electrical energy storage is critical not only to support electronic, vehicular and load-levelling applications but also to efficiently commercialize renewable energy resources such as solar and wind. While Li-ion batteries are being intensely researched for electric vehicle applications, there is a pressing need to seek for new battery chemistries aimed at stationary storage systems. In this aspect, Zn-ion batteries offer a viable option to be utilized for high energy and power density applications since every intercalated Zn-ion yields a concurrent charge transfer of two electrons and thereby high theoretical capacities can be realized. Furthermore, the simplicity of fabrication under open-air conditions combined with the abundant and less toxic zinc element makes aqueous Zn-ion batteries one of the most economical, safe and green energy storage technologies with prospective use for stationary grid storage applications. Also, Zn-ion batteries are very safe for next-generation technologies based on flexible, roll-up, wearable implantable devices the portable electronics market. Following this advantages, a wide range of approaches and materials, namely, cathodes, anodes and electrolytes have been investigated for Zn-ion batteries applications to date. Herein, we review the progresses and major advancements related to aqueous. Zn-ion batteries, facilitating energy storage/conversion via $Zn^{2+}$ (de)intercalation mechanism.

• Journal of Ceramic Processing Research
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• v.20 no.3
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• pp.222-230
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• 2019

Microwave hydrothermal-assisted sol-gel method was employed to synthesize the Fe doped TiO2 photocatalyst. The morphological analysis suggests anatase phase nanoparticles of ~20 nm with an SBET area of 283.99 ㎡/g. The doping of Fe ions in TiO2 created oxygen vacancies and Ti3+ species as revealed through the XPS analysis. The reduction of the band gap (3.1 to 2.8 eV) is occurred by doping effect. The as-prepared photocatalyst was applied for removal of NOx under solar light irradiation. The doping of Fe in TiO2 facilitates 75 % of NOx oxidation efficiency which is more than two-fold enhancement than the TiO2 photocatalyst. The possible reason of enhancement is associated with high surface area, oxygen vacancy, and reduction of the band gap. Also, the low production of toxic intermediates, NO2 gas, is further confirmed by Combustion Ion Chromatography. The mechanism related NOx oxidation by the doped photocatalyst is explained in this study.

• Applied Chemistry for Engineering
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• v.33 no.5
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• pp.502-522
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• 2022

Clay minerals are natural materials that show widespread applications in various branches of science, including environmental sciences, in particular the remediation of water contaminated with various water pollutants. Modified clays and minerals have attracted the attention of researchers in the recent past since the modified materials are seemingly more useful and efficient for removing emerging water contaminants. Therefore, modified engineered materials having multi-functionalities have received greater interest from researchers. The advanced clay-based materials are highly effective in the remediation of water contaminated with organic and inorganic contaminants, and these materials show enhanced selectivity towards the specific pollutants. The review inherently discusses various methods employed in the modification of clays and addresses the challenges in synthesizing the advanced engineered materials precursor to natural clay minerals. The changes in physical and chemical properties, as investigated by various characterization techniques before and after the modifications, are broadly explained. Further, the implications of these materials for the decontamination of waterbodies as contaminated with potential water pollutants are extensively discussed. Additionally, the insights involved in the removal of organic and inorganic pollutants are discussed in the review. Furthermore, the future perspectives and specific challenges in the scaling up of the treatment methods in technology development are included in this communication.

• Analytical Science and Technology
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• v.35 no.4
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• pp.153-160
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• 2022

A green spectrophotometric method for the determination of cyanide has been proposed using, a green reagent, aqueous extract of blue butterfly pea. The test tube was filled with anthocyanin rich extract (pH 6) and cyanide solution. The reaction was kept constant for 10 minutes at room temperature. The reaction mixture changed color from blue to green as the amount of CN-ions increased. The 620 nm peak intensity increased with CN concentration. Therefore, this wavelength was used for all cyanide analyses. The cyanide calibration curve had a linear range of 0.25-1.00, 1.00-4.00, and 4.00-10.00 mg/L, with a satisfactory correlation coefficient of 0.99 and a LOD of 0.57 mg/L. The recovery ranged from 8.33 to 76.94 percent, indicating that this method is inaccurate at low cyanide concentrations. The intra-day and intermediate precision relative deviations were 0.391-0.871 % and 1.112-1.583 %. An H-bond forms between the C-4 group of the B-carbonyl ring and the HCN molecule according to the B3LYP/TZVP calculation. The method is convenient for cyanide concentrations above the LOQ of 1.09 mg/L, cost-effective, and capable of reducing toxic solvents with acceptable precision. The method could also be used to detect total cyanide in biological, environmental, and industrial waste samples.

• The Korean Journal of Mycology
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• v.16 no.1
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• pp.1-8
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• 1988

Effect of suppression for zoosporangial germination and mycelial growth of Phyto­phthora capsici causing red pepper fruit rot, was carried out in vitro test by using $NH_4OH$ and $KNO_2$, as ammonium/ammonia, nitrite/nitrous acid and $CaCl_2$, as calcium ion. Results of in vitro tests with $NH_4OH$, $KNO_2$, and $CaCl_2$, mol solutions demonstrated that zoosporangial germination of P. capsici was inhibited about 15 to 50% compared with control, according to $NH_3$, HNO as nonionized form and $Ca^{+2}$ ions. Ammonia concentration$(NH_3)$ was proportionally increased by high pH level and mol concentration, whereas low pH and high mol concentration showed rather higher concentration of $HNO_2$. Ammonia were more toxic at pH 8 than at pH 7 under the same concentration, while nitrous acid$(HNO_2)$ was more toxic than at pH 8. The zoosporangial germination inhibition in the ammonium/ammonia and nitrite/nitrous acid solutions demonstrated that $NN_3$, and $HNO_2$, were primarily responsible for the inhibition at lower concentration and mor" toxic by increasing concentration. $Ca^{+2}$ ions showed that zoosporangial germination was inhibitory by high pH level and increasing mol concentration in comparison with buffer conlrol. pH levels affected to mycelial growth of the fungus, and especially, high pH caused rather retardation of mycelial growth. There was no definite inhibitory response of mycelial growth at various degree concentrations of the toxicant solutions.

• Journal of Microbiology and Biotechnology
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• v.27 no.6
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• pp.1138-1149
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• 2017

The use of microalgal biomass is an interesting technology for the removal of heavy metals from aqueous solutions owing to its high metal-binding capacity, but the interactions with bacteria as a strategy for the removal of toxic metals have been poorly studied. The goal of the current research was to investigate the potential of Burkholderia tropica co-immobilized with Chlorella sp. in polyurethane discs for the biosorption of Hg(II) from aqueous solutions and to evaluate the influence of different Hg(II) concentrations (0.041, 1.0, and 10 mg/l) and their exposure to different contact times corresponding to intervals of 1, 2, 4, 8, 16, and 32 h. As expected, microalgal bacterial biomass adhered and grew to form a biofilm on the support. The biosorption data followed pseudo-second-order kinetics, and the adsorption equilibrium was well described by either Langmuir or Freundlich adsorption isotherm, reaching equilibrium from 1 h. In both bacterial and microalgal immobilization systems in the co-immobilization of Chlorella sp. and B. tropica to different concentrations of Hg(II), the kinetics of biosorption of Hg(II) was significantly higher before 60 min of contact time. The highest percentage of biosorption of Hg(II) achieved in the co-immobilization system was 95% at pH 6.4, at 3.6 g of biosorbent, $30{\pm}1^{\circ}C$, and a mercury concentration of 1 mg/l before 60 min of contact time. This study showed that co-immobilization with B. tropica has synergistic effects on biosorption of Hg(II) ions and merits consideration in the design of future strategies for the removal of toxic metals.

• YAKHAK HOEJI
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• v.55 no.2
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• pp.106-115
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• 2011

Systematic toxicological analysis (STA) means the process for general unknown screening of drugs and toxic compounds in biological fluids. In order to establish STA, in previous study we investigated pattern of drugs & poisons in autopsy cases during 2007~2009 in Korea, and finally selected 62 drugs as target drugs for STA. In this study, rapid and simple drug identification and quantitative analytical program by gas chromatography-mass spectrometry(GC-MS) was developed. The in-house program, "DrugMan", consisted of modified chemstation data analysis menu and newly developed macro modules. Total 55 drugs among 62 target drugs were applied to this program, they were 14 antidepressants, 8 anti-histamines, 5 sedatives/hypnotics, 5 narcotic analgesics, 3 antipsychotic drugs, and etc. For calibration curves, fifty five drugs were divided into four groups of range considering their therapeutic or toxic concentrations in blood specimen, i.e. 0.05~1 mg/l, 0.1~1 mg/l, 0.1~5 mg/l or 0.5~10 mg/l. Standards spiked bloods were extracted by solid-phase extraction (SPE) with trimipramine-D3 as internal standard. Parameters such as retention times, 3 mass fragment ions, and calibration curves for each drug were registered to DrugMan. A series of identification, semi quantitation of target drugs and reporting the results were performed automatically. Calibration curves for most drugs were linear with correlation coefficients exceeding 0.98. Sensitivity rate of DrugMan was 0.90 (90%) for 55 drugs at the level of 0.5 mg/l. For standard spiked bloods at the level of 0.5 mg/l for 29 drugs, semi quantitative concentrations were ranged 0.36~0.64 mg/l by DrugMan. If more drugs are registered to database in DrugMan in further study, it will be useful tools for STA in forensic toxicology.

• Korean journal of applied entomology
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• v.61 no.1
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• pp.91-100
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• 2022

Ticks are the arthropod vector capable of transmitting diverse pathogens, which include bacteria, viruses, protozoan and fungi. Ticks are able to survive under stressful environmental conditions. One of evolutionary outcomes of these obligatory hematophagous arthropods is the survival for extended periods of time without a blood meal during off-host periods. Water conservation biology and heat tolerance have allowed ticks to thrive even under high temperatures and low relative humidity, thus they have become highly successful arthropods as they are distributed globally. Tick osmoregulatory physiology is a complex mechanism, which involves multiple osmoregulatory organs (salivary glands, Malpighian tubules, hindgut and synganglion) for the acquisition and excretion of water and ions. Blood feeding and water vapor uptake have been early reported as the primary passages for ixodid tick to acquire water. Recently, we have learned that ticks can actively drink environmental water allowing hydration. The acquired water can be traced to the salivary glands (type I acini) and the midgut diverticula. This opens new avenues for tick management through the delivery of toxic agents into their drinking water, in addition to an alternative strategy for the study of tick physiology. Here we address the osmoregulatory physiology in the ixodid ticks as a potential target physiological mechanism for tick control. We discuss the implications of water drinking behavior for tick control through the delivery of toxic agents and discuss the dermal excretion physiology as an additional pathway to induce tick dehydration and tick death.

• Economic and Environmental Geology
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• v.32 no.4
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• pp.385-398
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• 1999

The Narim gold mine is located approimately 200km southeast of Seoul within the Muju mineralized district of the Sobaegsan gneiss complex, Korea. Environmental geochemistry were undertaken for various kinds of water (surface, ground and mine water) collected of April, September and November in 1998 from the narim mine creek. Hydrogeochemical compositions of water samples are characterized by the relatively significant enrichment of Na+K, alkali ions, $HCO_{3}$, $NO_{3}$, Cl and F in groundwater, wheras the mine and surface waters are relatively enriched in Ca+Mg, hea표 metals and $SO_{4}$. Therefore, the groundwaters belong to the (Na+Ca)-( $HCO_{3}+SO_{4}$) type, respectively. The pH and EC values of the non-mining creek surfers are relatively lower compared with those of the surface water of the mine and ore dump area. The d values ($\delta$D-8$\delta^{18}$O) of all kinds of water from the Narim mine creek are 5.8 to 13.1 The range of $\delta$D and $\delta^{18}$O values (relative to SMOW) are shown in distinct two groups as follows: for the April waters of -64.8 to -67.8$\textperthousand$ and -9.6 to -10.0$\textperthousand$(d value=10.1 to 13.1), and for the November waters of -65.9 to -70.2$\textperthousand$ and -9.3 to -9.6$\textperthousand$ (d value=5.8 to 7.9), respectively. This range variation indicates that two group water were composed of distinct waters with seasonal difference. Geochemical modeling showed that mostly toxic metals (As, Fe, Mn, Ni, Pb, Zn) may exist largery in the from of metal $(M2^+)$ and metal-sulfate $(MSO_4\;^{2-$\mid$),\; and \;SO_4^{2-$\mid$}$ concentration influenced the speciation of heavy metals in the meteoric water. These metals in the groundwater could be formed of $CO_3 \;and \;(OH)_3$ complex ions. Using computer program, saturation index of albite, calcite, dolomite in meteoric water show undersaturated and progreddively evolved toward the saturation state, however, ground and mine water are nearly saturated. The gibbsited water-mineral reaction and stabilities suggest that the weathering of silicate minerals may be stable kaolinite, illite and Nasmectite. The clay minerals will be transformed to more stable kaolinite owing to the contiunous reaction.

• Economic and Environmental Geology
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• v.33 no.6
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• pp.505-517
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• 2000

This study was undertaken to provide a drinking water quality on the basis of physicochemical properties. In this study, the 25 samples of supply waters of the Taejon area were sampled twice (February and August in 1999). Hydrochemistry of the supply water belongs to the $Ca^{2＋}$-${HCO_3}^{-1}$ type, whereas the supply water was characterized by the relatively significant enrichment of ${Ca}^{2+}$, ${Na}^{2+}$, ${K}^{2+}$, ${Cl}^{2+}$ ions and heavy metals compared to the original water from the Daecheong lake. Generally, the supply water has a mean values for $10.7^{\circ}C$ of temperature, 6.86 of pH, -12 mV of Eh, 88 ${\mu}S$/cm of EC and 70.379 mg/l of TDS in February, whereas the waters of the same sites in August are a slightly high temperature ($26.1^{\circ}C$), TDS (78.069 mg/l) and extremely high EC (442 ${\mu}S$/cm) value. These values are similar with physicochemical properties of the original lake water depending on the seasonal differences. Results of speciation calculation indicate that potentially toxic ions might exist mainly in the forms of free metal (${Cu}^{2+}$ or ${Zn}^{2+}$) and a small amount of ${CO_3}^{2-}$and ${OH}^{-}$in the supply water. The water seemed to be in equilibrium with kaolinite field of the normal stability diagrams for the natural water. Based on enrichment parameter of the supply water normalized by original lake water composition, the average value of those parameter can be calculated with nearly 1.00, but the those values for Cu＋Zn possible source of decrepit pipe lines are 126.75 in February and 115.63 in August samples. The parameter values varied with sampling sites, however, do not exceed by chemistry of drinking water standard. Solid compounds remained on the membrane filter papers after filtration are adhered to pale yellow or yellowish brown colored dissolved solids and precipitates, which are coated by 0.02 to 0.35 mm thick per 500 ml with colloidal particles of about 1 to 2${\mu}m$ size. The particles are mainly Fe-Cu-Zn compounds and partly detected to Mn and Pb.