• Food Science and Preservation
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• v.18 no.6
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• pp.907-915
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• 2011

Moju is a low-alcoholic beverage made by filtering after boiling a mixture of makgeolli, ginseng, arrowroot, licorice root, cinnamon, jujube, ginger, and raw sugar. It is known to alleviate hangovers. To provide information for use in the development of palatable Moju, this study evaluated the physicochemical and sensory properties of 22 kinds of Moju being sold at different restaurants in Jeonju city. The mean values of obtained in the physicochemical analysis were as follows: water content, 91.28%; alcohol content, 1.09%; pH, 4.25; total acidity, 0.27%; reducing sugar content, 40.68 mg/mL; soluble solid content, 13.75 $^{\circ}Brix$; and viscosity 11.19 cP. The Lactic-, malic-, and citric- acid contents were higher than the contents of other organic acids. The sucrose content was higher than the contents of other free sugars. The mean value of the free amino acids was 175.3 mg%, lower than that of Takju, the main ingredient of Moju. It was considered that the free amino acids in Takju can be used as a substrate for the browning reaction in the process of Moju manufacture. In the sensory evaluation, the Moju with 0.15~0.25% total acidity, 10.6~13.4 $^{\circ}Brix$, and 5.73~9.57 cP was preferred.

• Food Science and Preservation
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• v.19 no.4
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• pp.492-500
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• 2012

This study was conducted to develop a sauce prepared with sweet pumpkin and Korea Doenjang. The optimum conditions for manufacturing sweet pumpkin-doenjang sauce were investigated using the response surface methodology, based on the central composition design. The amount of stock added, the thickening agent, and doenjang were used as the independent variables, and the sensory characteristics (taste, flavor, color, and overall acceptability) were used as the dependent variables to evaluate the optimum conditions for the preparation of the sauce. The optimum conditions for the maximized-responses variables in the preparation of the sauce were 448.5 g of sweet pumpkin stock, 331.5 g of the thickening agent, and 20.0 g of doenjang. The quality characteristics of sweet pumpkin-doenjang sauce that was manufactured at optimum conditions were as follow: 89.55% moisture content, 0.70% crude protein, 0.10% crude lipids, and 0.71% crude ash. The pH of the sauce was 5.96; total acidity, 0.08%; and soluble solids, 6.80$^{\circ}Brix$. The total polyphenol content of the sauce was 5.70 mg/L. The electron-donating ability and reducing power of the sauce were, 14.24% and 1.64 OD, respectively.

• Korean Journal of Soil Science and Fertilizer
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• v.4 no.1
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• pp.101-107
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• 1971

1. 수도(水稻)의 생육기간(生育其間)만이라도 심수하(甚水下)에 있어야하는 논은 투수성(透水性)의 영향(影響)을 받아야 하고, 동영향(同影響)은 수도생육(水稻生育)과 관련(關聯)을 갖는다. 즉(卽) 투수성(透水性)이 클 경우(境遇)에는 물의 소비(消費)가 많을 뿐만이 아니라 영양분(營養分)의 유실(流失) 및 유효화(有效化)가 억제(抑制)되고, 투수성(透水性)이 적을 경우(境遇)에에는 심(甚)한 환원상태(還元狀態)의 발달(發達)로 유해성분(有害成分)이 집적(集積)되어 수도(水稻)의 생육(生育)은 해(害)를 입게된다. 이렇게 생각하면 투수성(透水性)으로 본 벼 생육(生肉)에 가장 적합(適合)한 토양조건(土壤條件)이 있을 것인바 이 조건(條件)은 토양(土壤)의 종류외(種類外)에도 수도(水稻)의 품종(品種)이나 생육시기(生育時期)에 따라 다른것이다. 2. 투수성(透水性)이 큰 토양(土壤)에는 잘 유거(流去)되지 않는 비료(肥料)(유기물비료(有機物肥料)나 용성연비(熔成憐肥) 등(等))를 쓸것이며, 투수성(透水性)이 적고 유해성분(有害成分)이 집적(集積)되기 쉬운 토양(土壤)에는 류산근(류硫酸根)이나 유기질(有機質) 비료등(肥料等) 유해성분(有害成分)의 집적(集積)을 증가(增加)할 우려가 있는 비료(肥料)의 시용(施用)을 삼가야 한다. 3. 기왕(旣往) 국내(國內)에서 실시(實施)한 시험결과(試驗結果)에 의(依)하면 중점토(重粘土)에서는 연산(憐酸), 중점토(重粘土)와 퇴화염토(退化鹽土)에서는 가리결핍(加里缺乏)을 일으키기 쉬운것 같으나 그 밖의 토양(土壤)에서는 뚜렷한 경향(傾向)이 인정(認定)되지 않는다. 4. 투수성(透水性)이 큰 토양(土壤)에서는 산적토(山赤土)를 객토(客土)하는 경우(境遇)가 많은 바 이때에는 금비(金肥) 특(特)히 질소질비료(窒素質肥料)를, 객토(客土)하지 않았을때 보다 많이 써야 하는것이 일반적(一般的)이다. 5. 투수성(透水性)이 약(弱)하고 유해성분(有害成分)이 집적(集積)되기 쉬운 논에는 우선(于先) 석회(石灰)(소석회(消石灰))를 시용(施用)하여 토양반응(土壤反應)을 높여야 하며 심(甚)한 노후답(老朽畓)이나 퇴화염토(退化鹽土)에는 석회(石灰)와 아울러 규산질(珪酸質) 비료(肥料)를 시용(施用)한 연후(然後)에 비료(肥料) 삼요소(三要素) 시용(施用)을 고려(考慮)해야 할 것이다. 산성(酸性)으로 기울어져있는 많은 우리나라 논 토양(土壤)에는 알칼리성(性) 비료(肥料)인 용성연비(熔成憐肥)를 시용(施用)하는 것이 효과적(效果的) 일것이다. 6. 소석회(消石灰)와 규산(珪酸)의 시용(施用)은 연산(憐酸)과 가리(加里)의 요구량(要求量)을 증가(增加) 할것이며 비료(肥料) 삼요소(三要素)에 대(對)한 수도(水稻)의 응수곡선(應酬曲線)의 모습을 기왕(旣往)의 것과 달리 할것이다.

• Applied Chemistry for Engineering
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• v.32 no.6
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• pp.684-689
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• 2021

In this paper, we develop a cost effective and disposable voltammetric sensing platform involving screen-printed carbon electrode (SPCE) modified with the nanocomposites composed of multi-walled carbon nanotubes, polyelectrolyte, and tyrosinase for bisphenol A. This is known as an endocrine disruptor which is also related to chronic diseases such as obesity, diabetes, cardiovascular and female reproductive diseases, precocious puberty, and infertility. A negatively charged oxidized multi-walled carbon nanotubes (MWCNTs) wrapped with a positively charged polyelectrolyte, e.g., polydiallyldimethylammonium, was first wrapped with a negatively charged tyrosinae layer via electrostatic interaction and assembled onto oxygen plasma treated SPCE. The nanocomposite modified SPCE was then immersed into different concentrations of bisphenol A for a given time where the tyrosinase reacted with OH group in the bisphenol A to produce the product, 4,4'-isopropylidenebis(1,2-benzoquinone). Cyclic and differential pulse voltammetries at the potential of -0.08 V vs. Ag/AgCl was employed and peak current changes responsible to the reduction of 4,4'-isopropylidenebis(1,2-benzoquinone) were measured which linearly increased with respect to the bisphenol A concentration. In addition, the SPCE based sensor showed excellent selectivity toward an interferent agent, bisphenol S, which has a very similar structure. Finally, the sensor was applied to the analysis of bisphenol A present in an environmental sample solution prepared in our laboratory.

• Journal of the Korean Chemical Society
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• v.65 no.5
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• pp.358-369
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• 2021

In this study, the contents of the electron transfer model presented in the 4 chemistry I and the 4 chemistry II textbooks of 2009 revised curriculum and 9 chemistry I textbooks and 6 chemistry II textbooks of 2015 revised curriculum were analyzed in the viewpoint of model's Ignorance. In addition, 3 questions were developed to find out whether 24 pre-service teachers were perceived of the Ignorance of the electron transfer model. As a result, Most textbooks explain the redox reaction of covalent bond substances, which is an inconsistent context of the electron transfer model, with mixing oxidation number change and electron transfer or with electron transfer. In addition, the change to the development and use of the model emphasized in the 2015 revised curriculum was not clearly revealed in the curriculum comparison. Most pre-service teachers incompletely perceived or did not perceive Ignorance of the electron transfer model. Only 1 pre-service teacher perceived Ignorance of the model. In conclusion, the textbook description needs to be improved so that Ignorance of the model is revealed when the textbook describes the inconsistent situation of the electron transfer model. And through the education for pre-service teachers, it is necessary to provide an opportunity for pre-service teachers to perceive Ignorance of the electron transfer model.

• Korean Chemical Engineering Research
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• v.56 no.6
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• pp.884-889
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• 2018

In this study, polyaniline $(PANI)/WO_3$ electrode was prepared as an anode of a lithium ion capacitor, and its electrochemical characteristics were measured and analyzed. When PANI was electrochemically deposited on the surface of $WO_3$ electrode, the capacity of $PANI/WO_3$ was improved with increase of the deposited amounts of PANI. Furthermore, the effect of light irradiation on capacity and coulombic efficiency was examined by irradiating sunlight during charging and discharging. When the light was irradiated to the $WO_3$ electrode and the $PANI/WO_3$ electrode, those capacities and coulombic efficiencies were increased compared to that measured under the dark condition. It is attributed to the photocatalytic property of $WO_3$ that can generate photoelectrons by light irradiation. In $PANI/WO_3$ electrode, PANI also can be excited under the light irradiation with affecting the electrochemical property of electrode. The photoelectrons improve the capacity by participating in the intercalation of $Li^+$ ions, and also improve the coulombic efficiency by facilitating electrons' transport. Under the dark condition, the capacity of $PANI/WO_3$ was gradually reduced with increase of cycles due to a poor stability of PANI. However, the stability of PANI was significantly improved by the light irradiation, which is attributed to the oxidation-reduction reaction originated from the photogenerated electrons and holes in $PANI/WO_3$.

• Economic and Environmental Geology
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• v.53 no.6
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• pp.655-666
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• 2020

This study evaluated the characteristics of arsenic production in groundwater through microbial community analysis of groundwater contaminated with high arsenic in Haman area. Groundwater in Haman area is contaminated with arsenic in the range of 0-757.2 ㎍/L, which represents the highest arsenic contamination concentration reported in Korea as natural groundwater pollution source. Of the total 200 samples, 29 samples (14.5%) showed higher arsenic concentration than that of 10 ㎍/L, which is the standard for drinking water quality, and 8 samples (4%) found in wells with 80-100 m depth were above 50 ㎍/L. In addition, seven wells with arsenic concentration more than 100 ㎍/L located in the northern part of Haman. As a result of microbial community analysis for high arsenic-contaminated groundwater, the microbial community compositions were significantly different between each sample, and Proteobacteria was the most dominant phyla with an average of 61.5%. At the genus level, the Gallinonella genus was predominant with about 12.8% proportion, followed by the Acinetobacter and Methermicoccus genus with about 7.8 and 7.3%, respectively. It is expected that high arsenic groundwater in the study area was caused by a complex reaction of geochemical characteristics and biogeochemical processes. Therefore, it is expected that the constructed information on geochemical characteristics and microbial communities through this study could be used to identify the origin of high arsenic groundwater and the development of its controlling technology.

• Journal of the Korean institute of surface engineering
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• v.54 no.1
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• pp.1-11
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• 2021

Porous dendrite structure AuCu alloy was formed using a hydrogen bubble template (HBT) technique by electroplating to improve the catalytic performance of gold, known as an excellent oxygen reduction reaction (ORR) catalyst in alkaline medium. The rich Au surface was maximized by selectively electrochemical etching Cu on the AuCu dendrite surface well formed in a leaf shape. The catalytic activity is mainly due to the synergistic effect of Au and Cu existing on the surface and inside of the particle. Au helps desorption of OH- and Cu contributes to the activation of O2 molecule. Therefore, the porous AuCu dendrite alloy catalyst showed markedly improved catalytic activity compared to the monometallic system. The porous structure AuCu formed by the hydrogen bubble template was able to control the size of the pores according to the formation time and applied current. In addition, the Au-rich surface area increased by selectively removing Cu through electrochemical etching was measured using an electrochemical calculation method (ECSA). The results of this study suggest that the alloying of porous AuCu dendrites and selective Cu dissolution treatment induces an internal alloying effect and a large specific surface area to improve catalyst performance.

• Journal of Life Science
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• v.31 no.12
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• pp.1142-1148
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• 2021

As the average human lifespan has been extended, there has been a lot of interest in the quality of life of women after menopause. It is known that the average age of menopause among Korean women is 49.7 years, and the post-menopausal life of a woman takes up more than one third of her life. L-ascorbic acid (AsA) is known to be involved in the synthesis and maturation of collagen, a bone constituent protein. The aim of this review is to discuss the potential of AsA in bone health in postmenopausal women. AsA plays an important role in collagen biosynthesis, and collagen is a protein constituting bone and is a necessary material for calcification of the bone matrix. Collagen crosslinking is necessary for the stabilization and elasticity of collagen fibers during growth and matruation of animals, but an excessive increase is likely to lead to further aging because the movement of intercellular nutrients or waste is suppressed. AsA acts as a reducing agent to stabilize the immature collagen crosslinking and suppress pyridinoline production, a mature crosslinking. Therefore, AsA participates in collagen biosynthesis and helps bone tissue health, while regulating the excessive maturation of collagen crosslinking, it is expected to play an important role in bone-related problems that may occur in postmenopausal women.

• Applied Chemistry for Engineering
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• v.33 no.2
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• pp.126-132
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• 2022

Alkaline fuel cells using liquid fuels such as hydrazine and ammonia are gaining great attention as a clean and renewable energy solution possibly owing to advantages such as excellent energy density, simple structure, compact size in fuel container, and ease of storage and transportation. However, common shortcomings including cathode flooding, fuel crossover, side yield reactions, and fuel security and toxicity are still challenging issues. Real time monitoring of fuel concentrations integrated into a fuel cell device can help improving fuel cell performance via predicting any loss of fuels used at a cathode for efficient energy production. There have been extensive research efforts made on developing real-time sensing platforms for hydrazine and ammonia. Among these, recent advancements in electrochemical sensors offering high sensitivity and selectivity, easy fabrication, and fast monitoring capability for analysis of hydrazine and ammonia concentrations will be introduced. In particular, research trend on the integration of metallic and metal oxide nanoparticles and also their hybrids with carbon-based nanomaterials into electrochemical sensing platforms for improvement in sensitivity and selectivity will be highlighted.