• 한국수학교육학회지시리즈C:초등수학교육
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• 제21권4호
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• pp.431-444
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• 2018

본 연구에서는 문헌연구와 초등학교 3-6학년 학생들을 대상으로 한 설문의 통계적 검증을 토대로 초등학교 학생을 대상으로 하는 수학 불안 측정 도구를 개발하였다. 측정 도구는 수학 사교육 여부와 상관없이 수학 불안을 측정할 수 있는 도구와 수학 사교육에 참여하는 학생들에게 추가적으로 적용할 수 있는 도구, 총 2종으로 개발되었다. 문헌 연구 결과를 바탕으로 수학 불안 측정 도구는 수학 시험, 수학 수업, 수학 교사, 수학 수업과 관련한 부모님의 태도, 수학 상황에 대한 걱정이라는 다섯 가지 요인을 기반으로 설계되었다. 수학 사교육 관련 수학 불안 측정 도구는 사교육 수학 시험, 사교육 수학 수업, 사교육 교사라는 세 가지 요인을 기반으로 제작되었다. 본 연구에서는 신뢰도 검증을 위해 두 측정 도구에 대해 주성분분석(Principal Component Analysis)을 실시하였다. 또한 연구 참여자에게 수학 불안과 음의 상관관계가 있는 것으로 알려져 있는 수학 자기 효능감 측정 도구를 적용, 본 연구에서 개발한 측정도구와의 상관관계를 통계적으로 분석하여 타당도 검증을 실시하였다. 문헌연구, 통계적 분석을 기반으로 한 신뢰도 타당도 검증을 통해 본 연구에서는 21개의 수학 불안 측정도구 문항과 7개의 수학 사교육 관련 수학 불안 측정 도구 문항을 확정하였다.

• 한국수학교육학회지시리즈C:초등수학교육
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• 제23권2호
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• pp.63-72
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• 2020

본 연구의 목표는 초등학교 3~6학년 학생을 대상으로 하는 수학 자기 효능감 검사 도구를 개발하는데 있다. 본 연구에서는 문헌연구에서 도출된 수학 자기 효능감 하위 요인을 중심으로 검사 도구 문항을 개발하였다. 이 후 개발된 문항을 초등학교 3-6학년 학생들로 구성된 연구 참여자에게 적용하여 설문 결과를 통계적으로 분석하였다. 특히 본 연구에서는 주성분분석(Principal Component Analysis)을 이용해 설문 도구의 신뢰도를 검증하였다. 타당도 검증을 위해서는 수학 자기 효능감과 음의 상관관계가 있는 수학 불안 상태를 별도로 측정하여, 본 연구에서 개발한 측정도구와의 관계를 통계적 방법으로 분석하였다. 본 연구에서 개발된 초등학생의 수학 자기 효능감 검사도구는 향후 초등학생의 수학 자기 효능감 상태를 진단하고, 이를 토대로 수학 자기 효능감를 증진시키는 방안을 모색하는데 기초 자료가 될 것으로 기대된다.

• 한국수학교육학회지시리즈E:수학교육논문집
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• 제35권1호
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• pp.1-14
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• 2021

수학불안은 수학에 대한 정서적·신체적 거부감을 통칭하는 용어이다. 학생들의 수학불안에 대해 이해하는 것은 수학학업 성취도 향상 뿐 아니라 미래 사회에 필요한 수학 인력 양성의 측면에서도 중요하다. 특히 수학불안은 대부분 초등학교시기에 발생할 가능성이 높으며, 후속 학습에 부정적인 영향을 미치기 때문에 초등학교에서 학생들의 수학불안 양상을 이해하는 것이 필요하다. 이에 본 연구는 시간의 경과에 따른 학생들의 수학불안 변화 패턴을 제시하고 이를 통계적으로 검증하였다. 249명의 초등학교 학생들의 수학불안을 4학년에서 6학년까지 3년 동안 추적 조사한 결과, 수학불안 양상의 다섯 가지 패턴을 확인하였다. 또한 본 연구에서는 수학불안 변화에 지속적인 영향을 미치는 것은 교사의 수학 수업에 대한 흥미도이며, 부모의 관심은 수학불안을 경감시키고, 사교육에 대한 부담감은 수학불안을 증가시킨다는 것을 확인하였다.

• Journal of Microbiology and Biotechnology
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• 제32권4호
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• pp.473-483
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• 2022

In this study we investigated the effect of lactic acid bacteria (LAB) fermentation on the ingredients and anti-oxidant activity of Withania somnifera extract. Four strains of LAB could proliferate normally in medium containing W. somnifera extract after the pH reached 3.1~3.5. LAB fermentation increased the content of alcohols and ketones, endowing the extract with the characteristic aroma of fermentation. Compared to the control, the DPPH and ABTS free radical scavenging rates in the fermented samples were significantly improved, ranging from 48.5% to 59.6% and 1.2% to 6.4%. The content of total phenols was significantly increased by 36.1% during the fermentation of mixed bacteria. Moreover, the original composition spectrum of the extract was significantly changed while the differentially accumulated metabolites (DAMs) were closely related to bile secretion, tryptophan metabolism and purine metabolism. Therefore, LAB fermentation can be used as a promising way to improve the flavor and bioactivity of the extracts of W. somnifera, making the ferments more attractive for use as functional food.

• Journal of Radiation Protection and Research
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• 제47권2호
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• pp.77-85
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• 2022

Background: After the Fukushima Daiichi Nuclear Power Station (FDNPS) accident, a model was developed to estimate the external exposure doses for residents who were expected to return to their homes after evacuation orders were lifted. However, the model's accuracy and uncertainties in parameters used to estimate external doses have not been evaluated. Materials and Methods: The model estimates effective doses based on the integrated ambient dose equivalent (H^*(10)) and life patterns, considering a dose reduction factor to estimate the indoor H^*(10) and a conversion factor from H^*(10) to the effective dose. Because personal dose equivalent (H_p(10)) has been reported to agree well with the effective dose after the FDNPS accident, this study validates the model's accuracy by comparing the estimated effective doses with H_p(10). The H_p(10) and life pattern data were collected for 36 adult participants who lived or worked near the FDNPS in 2019. Results and Discussion: The estimated effective doses correlated significantly with H_p(10); however, the estimated effective doses were lower than H_p(10) for indoor sites. A comparison with the measured indoor H^*(10) showed that the estimated indoor H^*(10) was not underestimated. However, the H_p(10) to H^*(10) ratio indoors, which corresponds to the practical conversion factor from H^*(10) to the effective dose, was significantly larger than the same ratio outdoors, meaning that the conversion factor of 0.6 is not appropriate for indoors due to the changes in irradiation geometry and gamma spectra. This could have led to a lower effective dose than H_p(10). Conclusion: The estimated effective doses correlated significantly with H_p(10), demonstrating the model's applicability for effective dose estimation. However, the lower value of the effective dose indoors could be because the conversion factor did not reflect the actual environment.

• Current Photovoltaic Research
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• 제10권4호
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• pp.101-106
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• 2022

We prepared a CsPbI₂Br solution using Cesium iodide (CsI), Lead (II) bromide (PbBr₂) and Lead (II) iodide (PbI₂) materials into a polar solvent mixture of N,N-dimethylformamide (DMF) and Dimethyl sulfoxide (DMSO). A simple spin coating technique was used for the fabrication of CsPbI₂Br absorber layer in the solution process. In order to prepare uniform coating of absorber film we adopted a hot-air process in assocation with the spin coating. It was confirmed that the thin film manufactured by the hot-air process had a higher absorption rate than that without it, and the optical band gap was measured 1.93 eV. The thin film of absorber was uniformly prepared and revealed the Black α-Cubic crystal phase as proved through X-ray diffraction analysis. Finally, a perovskite solar cell having an n-i-p structure was manufactured with a CsPbI₂Br perovskite absorption layer. From the solar cell, we obtained a power conversion efficiency (PCE) of 5.97% in a forward measurement.

• Animal Bioscience
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• 제35권4호
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• pp.614-623
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• 2022

Objective: The objective of this study was to investigate the effects of sheep slaughter age on myogenic characteristics in skeletal muscle satellite cells (SMSCs). Methods: Primary SMSCs were isolated from hind leg biceps femoris muscles of Wurank lambs (slaughtered at three months, Mth-3) and adults (slaughtered at fifteen months, Mth-15). SMSCs were selected by morphological observation and fluorescence staining. Myogenic regulatory factors (MRF) and myosin heavy chain (MyHC) expressions of SMSCs were analyzed on days 1, 3, 4, and 5. Results: The expressions of myogenic factor 5 (Myf5), myogenic differentiation (MyoD), Myf6, and myogenin (MyoG) in Mth-15 were significantly higher in Mth-15 than in Mth-3 on days 1, 3, and 4 (p<0.05). However, MyoG expression in Mth-15 was significantly lower than in Mth-3 on day 5 (p<0.05). The expressions of MyHC I, MyHC IIa, and MyHC IIx in Mth-15 were significantly higher than in Mth-3 on days 1 and 3 (p<0.05), and MyHC IIb were significantly lower than in Mth-3 on days 3 and 4 (p<0.05). In contrast, the expression of MyHC IIx in Mth-15 was significantly lower and MyHC IIb was significantly higher than in Mth-3 on days 5 (p<0.05). Conclusion: The slaughter age altered the expression of MRFs and MyHCs in SMSCs while differentiation, which caused the variation of myogenic characteristics, and thus may affect the meat quality of Wurank sheep.

• Restorative Dentistry and Endodontics
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• 제48권1호
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• pp.4.1-4.10
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• 2023

Objectives: This study aimed to compare the torsional and cyclic fatigue resistance of ProGlider (PG), WaveOne Gold Glider (WGG), and TruNatomy Glider (TNG). Materials and Methods: A total of 15 instruments of each glide path system (n = 15) were used for each test. A custom-made device simulating an angle of 90° and a radius of 5 millimeters was used to assess cyclic fatigue resistance, with calculation of number of cycles to failure. Torsional fatigue resistance was assessed by maximum torque and angle of rotation. Fractured instruments were examined by scanning electron microscopy (SEM). Data were analyzed with Shapiro-Wilk and Kruskal-Wallis tests, and the significance level was set at 5%. Results: The WGG group showed greater cyclic fatigue resistance than the PG and TNG groups (p < 0.05). In the torsional fatigue test, the TNG group showed a higher angle of rotation, followed by the PG and WGG groups (p < 0.05). The TNG group was superior to the PG group in torsional resistance (p < 0.05). SEM analysis revealed ductile morphology, typical of the 2 fracture modes: cyclic fatigue and torsional fatigue. Conclusions: Reciprocating WGG instruments showed greater cyclic fatigue resistance, while TNG instruments were better in torsional fatigue resistance. The significance of these findings lies in the identification of the instruments' clinical applicability to guide the choice of the most appropriate instrument and enable the clinician to provide a more predictable glide path preparation.

• Journal of Animal Science and Technology
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• 제65권2호
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• pp.275-292
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• 2023

Nanotechnology in the food industry can increase the effectiveness of food ingredients. Nanotechnology can increase the bioavailability and absorption of bioactive compounds, enhance their stability, and improve the sensory quality of the product. Processed meat products are easily damaged due to bacterial activity. Advanced nanoemulsions as a meat preservative are nanoemulsions that can be used as preservative agents in meat products, particularly essential oil nanoemulsions, due to their antimicrobial and antioxidant properties. Its application is still limited to foods made from meat products. Therefore, this literature review examines nanoemulsion and its application in meat products and functionality improvement. Also, in the future, nanoemulsions in meat products must be made safe, and the government and businesses must work together to build consumer trust. It can be concluded that essential oil-based nanoemulsion has the potential to be used as an additive in meat products because it can kill bacteria, fight free radicals, improve flavor, and keep food fresh. Nanoemulsion is challenging in the meat industry because it can be toxic due to its tiny droplets (under 200 nm).

• 한국수학교육학회지시리즈E:수학교육논문집
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• 제37권2호
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• pp.183-197
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• 2023

수학 청해력이란 수학적 원리와 개념이 내포된 음성 언어를 듣고 그 의미를 파악하는 능력을 지칭한다. 수학 청해력은 타 교과 수업, 일상생활 속 듣기와 구분된다. 본 연구에서는 수학 청해력 측정 도구를 활용하여 초등학교 학생 834명의 수학 청해력 실태를 조사하였다. 설문조사의 통계 분석 결과를 통해 학생들의 수학 청해력은 성별, 학년, 학교의 위치와 통계적으로 유의미한 상관관계가 있음을 확인하였다. 여학생의 수학 청해력이 남학생보다 높으며, 수학 청해력은 학년에 따라 증가하다가 6학년에서 다시 감소하는 것을 알 수 있었다. 또한 학교의 위치에 따라 학생들의 수학 청해력이 유의미한 차이를 보였다. 본 연구의 결과는 수학 청해력 관련 후속 연구, 교수·학습 자료 개발의 토대로 활용될 수 있다.