• Applied Biological Chemistry
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• v.45 no.3
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• pp.179-184
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• 2002

To examine utilization of Korean black soybean as a natural pigment, the effects of temperature, carbohydrate, organic acid, vitamin C and metal ion were investigated. Korean black soybean pigment was more stable than other anthocyanin pigments when temperature was abused. There was no darkness effect in carbohydrate. In organic acid, the color intensity was increased. The vitamin C addition negatively affected on color of anthocyanin. Among the metal ions tested, $Cu^{2+}$ and $Zn^{2+}$ was not affected but $Mn^{2+}$ makes it unstable. Results indicate that Korean black soybean pigment was more stable than other anthocyanin pigment in various environment at pH 3.

• Korean Journal of Food Science and Technology
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• v.33 no.1
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• pp.7-11
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• 2001

The influence of temperature and calcium concentration on the gelation kinetics of purified Aigeok system has been investigated by small deformation oscillatory measurement. DE(degree of esterification) of the present sample was indicated of low methoxyl Aigeok polysaccharide by FT-IR. The calcium induced gelation of Aigeok has been studied. Both moduli reached the saturation value during the period of experiments. Rate constant increased with increasing calcium concentration, however above 4.08 mM calcium chloride caused a sudden drop in gel strength. The experimental result that the decrease in gel strength at high calcium concentration was seems to be phase separation or competitive inhibition between calcium ions. The storage and loss shear moduli decreased with increasing temperature. The rate constant of Aigeok system remarkably dropped above $35^{\circ}C$. Thus hydrogen bonding is prior to hydrophobic interaction for Aigeok molecule.

• Korean Journal of Food Science and Technology
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• v.30 no.4
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• pp.733-738
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• 1998

Tannic acid (TA), chlorogenic acid (GA) and caffeic acid (CA) as copigments were added in anthocyanin solutions (pH 3.0) to test their effects on the stability against temperatures, metal ions, and light. Absorbance of anthocyanins increased with the increase of copigment concentrations. Tannic acid showed the highest absorbance increase with bathochromic shift of 14 nm (from 514 nm to 528 nm). Copigmentation resulted in higher storage stability of anthocyanins for 21 days at room temperature $925^{\circ}C)$ but lower thermal stability at higher temperatures more than $70^{\circ}C. Addition of metal ions to TA caused the enhanced stability as well as increased absorbance of anthocyanins. Copigmentation also caused a significant increase of light stablilty of anthocyanins at room temperature, so that addition of TA showed 2.3 times showed photodegradation of anthocyanins under 20,000 lux-light dosage in pH 3.0 solution at $25^{\circ}C$.

• Journal of Convergence for Information Technology
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• v.11 no.2
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• pp.117-123
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• 2021

The effects of electrolyte concentration on the electrochemical properties of Fe4[Fe(CN6)]3(FeHCF) as a novel active material for the electrode of aqueous zinc-ion batteries was investigated. The electrochemical reactions and structural stability of the FeHCF electrode were significantly affected by the electrolyte concentration. In the electrolyte solutions of 1.0-7.0 mol dm-3, the charge-discharge capacities increased with increasing electrolyte concentration, however gradually decreased as the cycle progressed. On the other hand, in the 9.0 mol dm-3 electrolyte solution, the initial capacity was relatively small, however showed good cyclability. Additionally, the FeHCF electrode after five cycles in the former electrolyte solutions, had a change in crystal structure, whereas there was no change in the latter electrolyte solution. This suggests that the performance of the FeHCF electrode is greatly influenced by the hydration structure of zinc ions present in electrolyte solutions.

• Applied Chemistry for Engineering
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• v.33 no.6
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• pp.606-612
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• 2022

The purpose of this study is to convert hydrophobic dyestuff to hydrophilic dyestuff by reacting cationic collector with anionic dyestuff and reaction anionic collector with cationic dyestuff. The removal of colors from aqueous solutions and/or dispersions has been studied by dispersed-air flotation in a batch column. In this studies used generated micro bubble by ceramic gas diffuser having micro pore size for air flotation process. In this study, a ceramic gas diffuser with micro pore size was used to generate micro bubbles for the air flotation process. Two colours were used for the experiments: Basic Yellow 1 (cationic dyestuff) and Direct Orange 10 (anionic dyestuff). All two were effectively removed by flotation within 8 mins. Sodium dodecyl sulfate, sodium oleate (an anionic collector), and amines (a cationic collector) were found to be effective as collectors in the removal of color, which was found to be related to the pH of the solution and the amount of collector added to it, with high collector dosages causing the process to become pH-independent.

• Applied Chemistry for Engineering
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• v.33 no.4
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• pp.343-351
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• 2022

Lithium-ion batteries (LIBs) are considered promising energy storage devices with good performance such as high energy density, slow self-discharge rate, high rate charge capacity, and long battery life. However, the application of these LIBs in the high-energy density electric vehicle and large device industries poses a major safety problem. In order to solve this problem, developing a material having high thermal stability and intrinsic safety is the ultimate solution for improving the stability and electrochemical performance of LIBs. This review introduced a surface modification technology of a separator to overcome the stability problem of a commercial separator, and summarized and summarized the research trends using the modified separator for a lithium-ion battery. Based on this, the future prospects for the separator development by surface modification were discussed.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.33 no.6
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• pp.203-209
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• 2023

Cobalt sulfide nanocomposites were synthesized through a simple hydrothermal method as anode materials for sodium ion batteries (SIBs). In this work, a cobalt sulfide nanoparticle (CoS-NF) and a cobalt sulfide nanocomposite integrated with reduced graphene oxide (CoS@G-NC) were fabricated for electrochemical energy storage performance of battery. The as-prepared CoS@G-NC electrode exhibited reversible and stable cycle performance (62 % after 30 cycles at current density of 200 mA g^-1). The improved electrochemical property was attributed to the small grain growth and uniform distribution of cobalt sulfide during synthesis, which maximized the diffusion pathway for sodium ions and effectively suppressed the delamination and volume expansion of cobalt sulfide during the conversion reaction. The results provide promising anode materials for next-generation SIBs.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.24 no.2
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• pp.127-132
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• 2024

Recently, secondary batteries, commonly known as rechargeable batteries, find widespread applications across various industries. Particularly valued for their compact and lightweight characteristics, they play a crucial role in diverse portable electronic devices such as smartphones, laptops, and tablets, offering high energy density and efficient charge-discharge capabilities. Moreover, they serve as vital components in electric vehicles and contribute significantly to the field of renewable energy as part of Energy Storage Systems(ESS). However, despite advancements in this technology, issues such as reduced lifespan, cracking, damage, and even the risk of fire can arise due to excessive charging and discharging of secondary batteries. To address these challenges, Battery Management System(BMS) are employed to protect against overcharging and improve overall performance. Nevertheless, understanding the protective range settings of BMS using lithium-ion batteries, the most commonly used secondary batteries, and lead-acid batteries can be challenging. Therefore, this paper aims to utilize a battery charge-discharge tester and simulator to investigate the charging and discharging characteristics of lithium-ion batteries and lead-acid batteries, addressing the associated challenges of reduced lifespan, cracking, damage, and fire hazards in secondary batteries.

• Journal of the Korean Society of Food Culture
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• v.7 no.4
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• pp.297-301
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• 1992

To investigate effects of the surface finishing methods (A : conventional press stone, B : enclosing in polyethylene (PE) bag, C : press-tone wrapped with PE film and D : covered with Chinese cabbage leaves 4cm in thickness on Kimchi) on Kimchi quality, pH-values, redness, film forming yeast growth, hardness and sensory quality of Kimchi during storage (for 60 days, at $10{\pm}5^{\circ}C$) in glass vessel $(11{\times}30cm)$ were investigated. pH of the top layer of A, C and D sample were higher than the optimum pH (4.2) of Kimchi, film forming yeast occurred on the surface of Kimchi, color of top layer Kimchi juice was darkened, and panel score of freshness and firmness was significantly worse (p<0.01) than that of sample B. However, in the case of Kimchi stored in PE bag (B), film forming yeast were can't detected visually in the surface of Kimchi, pH values were low as good quality Kimchi, freshness and firmness panel scores and hardness were significantly better (p<0.01) than A, C and D, and redness of juice of top layer of B was also preserved clearly for 60 days. Accordingly among the four surface finishing methods, the B-method was most effective in preserving of y of Kimchi.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.8
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• pp.1211-1219
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• 2013

Dasik is a kind of traditional Korean dessert, which has polysaccharides as the major base. Dasik was prepared using rice and various ingredients and its antioxidant properties were determined. In addition, textural changes and sensory evaluation were conducted on Dasik during 7-day storage at $4^{\circ}C$. Dasik containing brown rice, red ginseng, and rice bran oil showed higher radical scavenging ability, reducing power, total flavonoid, and total phenolic contents among tested rice-based samples. Dasik prepared using black sesame seeds showed the highest radical scavenging ability and reducing power compared to rice-based Dasik. In sensory evaluation, 10 trained panelists found that hardness of the rice-based Omija Dasik sample increased significantly (P<0.05) while moistness and softness attributes decreased as the storage period of Dasik increased. The roasted bean Dasik and black sesame Dasik samples were evaluated similarly and their moistness decreased significantly (P<0.05) with longer storage period. The overall and texture acceptability of the rice-based Omija Dasik and the roasted bean Dasik samples decreased significantly (P<0.05), and scores of willingness to try again of the rice-based Omija Dasik decreased as the storage period of Dasik increased. Positive or negative correlations among the results from sensory evaluation and textural analysis were observed in Dasik.