• Title/Summary/Keyword: 이종소재

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Analysis on Features of Prospective Mathematics Teachers' Motivation in Learning Mathematics (예비 수학교사의 수학 학습동기 특징 분석)

  • Lee, Jong-hak;Kim, Somin
    • Journal of the Korean School Mathematics Society
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    • v.23 no.4
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    • pp.491-508
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    • 2020
  • In this study, by measuring and analyzing the motivation of prospective mathematics teachers in learning mathematics, we tried to understand the features of prospective teachers' learning motivation and find the implications of developing expertise in terms of learning motivation. Prior research related to learning motivation identifies the three elements that consist of learning motivation as values, self-efficacy, and interest. Based on these elements, a survey tool was developed to investigate the learning motivation of prospective mathematics teachers. This survey was then carried out for 120 students in the mathematics education department of a local college. In addition, the survey asked what methods prospective teachers would choose for motivating their future students. According to the results of this study, the overall motivation of prospective mathematics teachers differed by grade (academic year) and there were significant differences between grades in self-efficacy and interest factors. In addition, the prospective teachers preferred to use interesting materials rather than inform the value of learning mathematics to induce learning motivation. Therefore, it is necessary to enhance this self-efficacy and interest in learning and to provide various material to strengthen this motivation for learning.

Development of a Cosmetic Ingredient Containing DHA Derivatives for Anti-inflammation, Anti-wrinkle, and Improvement of Skin Barrier Function (DHA 유도체를 이용한 항염, 항노화, 피부장벽 강화용 화장품 원료의 개발)

  • Lee, Miyoung;Lee, Gil-Yong;Suh, Jinyoung;Lee, Kyung min;Lee, Woojung;Cho, Hee Won;Yi, Jong-Jae;Seo, Jeong-Woo;Choi, Heonsik
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.47 no.1
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    • pp.65-73
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    • 2021
  • It is very important to control the inflammation of the skin because it can develop into diseases such as atopy as well as scarring and aging. In this work, we recently identified the in vitro synthesis of specialized pro-resolving mediators (SPMs) known to control inflammation in the human body and the applicability of cosmetics. Using recombinant protein of lipoxygenase from Glycine max, we succeeded to prepare mixtures of mono- or di-hydroxy DHA named as S-SPMs and used them for in vitro efficacy test. To investigate anti-inflammatory effect of S-SPMs, mRNA level of TNF-α and IL-6 were analyzed. Under UVB exposed condition, expression of both were decreased by S-SPMs treatment. And we observed reduced production of nitric oxide (NO) by S-SPMs application under the condition with diesel particulate matter (DPM). At the same experimental condition, malondialdehyde (MDA) production was decreased by S-SPMs, indicating the inhibitory effect of S-SPMs in lipid peroxidation. In addition, S-SPMs treatment resulted in reduction of matrix metalloproteinases-1 (MMP-1) expression and elevation of procollagen type I synthesis. Together with this, mRNA level of filaggrin and loricrin were increased by S-SPMs, indicating enhancement of skin barrier function. These results demonstrate that S-SPMs is a good candidate to develop as a cosmetic ingredient for anti-inflammation, anti-wrinkle, and improvement of skin barrier function.

Biotransformation of Ginsenoside Rd from Red Ginseng Saponin using Commercial β-glucanase (상업용 β-glucanase를 이용한 홍삼유래 사포닌으로부터 Ginsnoside Rd 의 생물 전환)

  • Kang, Hye Jung;Lee, Jong Woo;Park, Tae Woo;Park, Hye Yoon;Park, Junseong
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.46 no.4
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    • pp.349-360
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    • 2020
  • Bio-conversion manufacturing technology has been developed to produce ginsenoside Rd which is increasingly in demand as a cosmetic material due to various possibilities related to improving skin function. In order to convert ginsenoside Rb1 which is contained in red ginseng saponin (RGS) into Rd, several commercial enzymes were tested. Viscoflow MG was found to be the most efficient. In order to optimize the conversion of RGS to ginsenoside Rd by enzymatic transition was carried out using response surface methodology (RSM) based on Box-Behnken design (BBD). The main independent variables were RGS concentration, enzyme concentration, and reaction time. Conversion of ginsenoside Rd was performed under 17 conditions selected according to BBD model and optimization conditions were analyzed. The concentration of the converted ginsenoside Rd ranged from 0.3113 g/L to 0.5277 g/L, and the highest production volume was obtained under condition of reacting 2% RGS and 1.25% enzyme for 13.5 hours. Consequently, RGS concentration, enzyme concentration which is 0.05 less than p-value and among the interactions between the independent variables, the interaction between enzyme concentration and reaction time was confirmed to be the most influential.

Structural Analysis of University Students' Entrepreneurship, Entrepreneurial Self-efficacy, and Entrepreneurial Intention (대학생의 기업가정신, 창업자기효능감, 창업의지 간 구조분석)

  • Lee, Jong-Hun
    • The Journal of the Korea Contents Association
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    • v.21 no.5
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    • pp.695-706
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    • 2021
  • The purpose of this study was to establish entrepreneurship(risk taking, proactiveness, innovativeness), entrepreneurial self-efficacy, and entrepreneurial intention as a structural equation model to confirm the entrepreneurial intention of university students. In order to achieve the purpose of this study, 449 students from 3 university students in Gyeonggi-do were studied, and data analysis was conducted with SPSS 23.0 and AMOS 23.0 statistical programs. The results of the empirical analysis are as follows: First, Among university students' entrepreneurship, proactiveness was not statistically significant to entrepreneurial intention but, risk taking and innovativeness have been identified as having a direct impact. Second, University students' entrepreneurial self-efficacy directly affects entrepreneurial intention. Third, risk taking and innovativeness were statistically significant, but proactiveness was not affected. Finally, through the mediating of entrepreneurial self-efficacy, risk taking effects were fully sold to entrepreneurial intention, and innovativeness was partially sold to entrepreneurial intention. Based on the results of this study, the way to enhance university students' entrepreneurial intention is to develop programs that can improve their entrepreneurial self-efficacy and apply them actively to university education. In particular, university students need mentoring support from on-site entrepreneurial experts and internship education support to increase risk taking and innovativeness as prospective founders. The government can lead to entrepreneurial behavior when economic and institutional support precedes university students to recover from their initial entrepreneur.

Electrochemical Deposition Characteristics of Ca2+ on Cu Wire Electrode in CaCl2 Molten Salt (CaCl2 용융염에서 Ca2+의 Cu 전극에 대한 전기화학적 증착 특성평가)

  • Hwang, Dong Wook;Lee, Jong Hyeon;Jeong, Sang Mun
    • Korean Chemical Engineering Research
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    • v.60 no.2
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    • pp.175-183
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    • 2022
  • With the expansion of the automobile market, the demand for Nd as an essential rare earth material for automobile motors is rapidly increasing. Research on the calcio-thermic reduction process between Nd2O3 and calcium-based alloys has been extensively studied in order to manufacture Nd. In this study, Ca-Cu, as a reducing for Nd2O3, was prepared by electrolysis in CaCl2 molten salt. Cu wire and graphite were employed as a working electrode and a counter electrode for electrolysis reaction, respectively. The reference electrode was manufactured by putting Ag wire in a mixture of AgCl and CaCl2 at a ratio of 1:99 mol%. The cyclic voltammetry results showed that the deposition of Ca2+ on the surface of working electrode was observed from a potential of -1.8 V, and the reduction potential of Ca2+ decreased as the reaction temperature increased. The diffusion coefficient of Ca2+ calculated by the chronoamperometry experiment was found to be 5.4(±6.8)×10-6 cm2/s. In addition, Ca-Cu liquid alloy was prepared by applying a constant potential to Cu electrodes. The element ratio of Ca-Cu alloy formed by applying a potential of -2.0 V was found to Ca:Cu=1:4.

Development of CNT Coating Process using Argon Atmospheric Plasma (아르곤 상압플라즈마를 이용한 CNT 코팅 공정 기술 개발)

  • Kim, Kyoung-Bo;Lee, Jongpil;Kim, Moojin
    • Journal of Industrial Convergence
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    • v.20 no.10
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    • pp.33-38
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    • 2022
  • In this paper, a simple method of forming a solution-based carbon nanotube (CNT) for use as a conductive material for electronic devices was studied. The CNT thin film coating was performed on the glass by applying the spin coating method and the argon atmospheric pressure plasma process. In order to observe changes in electrical and physical properties according to the number of coatings, samples formed in the same manner from times 1 to 5 were prepared, and surface shape, reflectance, transmittance, absorbance, and sheet resistance were measured for each sample. As the number of coatings increased, the transmittance decreased, and the reflectance and absorptivity increased in the entire measurement wavelength range. Also, as the wavelength decreases, the transmittance decreases, and the reflectance and absorption increase. In the case of electrical properties, it was confirmed that the conductivity was significantly improved when the second coating was applied. In conclusion, in order to replace CNT with a transparent electrode, it is necessary to consider the number of coatings in consideration of reflectivity and electrical conductivity together, and it can be seen that 2 times is optimal.

Thermal Stress Induced Spalling of Metal Pad on Silicon Interposer (열응력에 의한 실리콘 인터포저 위 금속 패드의 박락 현상)

  • Kim, Junmo;Kim, Boyeon;Jung, Cheong-Ha;Kim, Gu-sung;Kim, Taek-Soo
    • Journal of the Microelectronics and Packaging Society
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    • v.29 no.3
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    • pp.25-29
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    • 2022
  • Recently, the importance of electronic packaging technology has been attracting attention, and heterogeneous integration technology in which chips are stacked out-of-plane direction is being applied to the electronic packaging field. The 2.5D integration circuit is a technology for stacking chips using an interposer including TSV, and is widely used already. Therefore, it is necessary to make the interposer mechanically reliable in the packaging process that undergoes various thermal processes and mechanical loadings. Considering the structural characteristics of the interposer on which several thin films are deposited, thermal stress due to the difference in thermal expansion coefficients of materials can have a great effect on reliability. In this study, the mechanical reliability of the metal pad for wire bonding on the silicon interposer against thermal stress was evaluated. After heating the interposer to the solder reflow temperature, the delamination of the metal pad that occurred during cooling was observed and the mechanism was investigated. In addition, it was confirmed that the high cooling rate and the defect caused by handling promote delamination of the metal pads.

Charge Storage Behavior of the Carbons Derived from Polyvinylidene Chloride-resin and Polyvinylidene Fluoride in Different pH Electrolytes (다른 pH의 전해질에서 polyvinylidene chloride-resin와 polyvinylidene fluoride로부터 합성된 다공성 탄소의 전하 저장 거동)

  • Sang-Eun, Chun
    • Composites Research
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    • v.35 no.6
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    • pp.394-401
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    • 2022
  • Two polymer precursors, polyvinylidene chloride-resin (PVDC-resin) and polyvinylidene fluoride (PVDF), are assembled into the microporous carbon by pyrolysis. Microporous carbon is advantageous as an electrode for supercapacitors that store electric charges through ion adsorption/desorption. The pyrolysis also turns the various heteroatoms of two precursors into functional groups, contributing to the additional charge storage. The analysis of the porous structure and function group during carbonization are important to develop the carbon for energy storage. Here, we analyzed the functional groups of two polymer-derived carbons through X-ray photoelectron spectroscopy. The electrochemical properties of the functional groups were explored in various pH electrolytes. The specific capacitance of two carbons in the acidic electrolyte (1 M H2SO4) was improved compared to that in the neutral electrolyte (0.5 M Na2SO4) due to the faradaic charge/discharge reaction of the quinone functional group. In particular, the carbon electrode derived from PVDC-resin exhibits a lower capacity than the carbon from PVDF due to the small micropores. In the alkaline electrolyte (6 M KOH), the highest specific capacitance and rate capability were obtained among the three electrolytes for both electrodes based on the facile adsorption of the constituent electrolyte ions (K+, OH-).

PEO/PPC based Composite Solid Electrolyte for Room Temperature Operable All Solid-State Batteries (상온에서 작동되는 전고체전지 용 PEO/PPC 기반의 복합 고체 전해질)

  • Shin, Sohyeon;Kim, Sunghoon;Cho, Younghyun;Ahn, Wook
    • Journal of the Korean Electrochemical Society
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    • v.25 no.3
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    • pp.105-112
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    • 2022
  • For the commercialization of all-solid-state batteries, it is essential to develop a solid electrolyte that can be operable at room temperature, and it is necessary to manufacture all-solid-state batteries by adopting materials with high ionic conductivity. Therefore, in order to increase the ionic conductivity of the existing oxide-based solid, Li7La3Zr2O12 (LLZO) doped with heterogeneous elements was used as a filler material (Al and Nb-LLZO). An electrolyte with garnet-type inorganic filler doped was prepared. The binary metal element and the polymer mixture of poly(ethylene oxide)/poly(propylene carbonate) (PEO/PPC) (1:1) are uniformly manufactured at a ratio of 1:2.4, The electrochemical performance was tested at room temperature and 60 ℃ to verify room temperature operability of the all-solid-state battery. The prepared composite electrolyte shows improved ionic conductivity derived from co-doping of the binary elements, and the PPC helps to improve the ionic conductivity, thereby increasing the capacity of all-solid-state batteries at room temperature as well as 60 ℃. It was confirmed that the capacity retention rate was improved.

Effects of rehabilitation trainer's perfectionism and self-efficacy on subjective quality of life (재활트레이너의 완벽주의와 자기효능감이 주관적 삶의 질에 미치는 영향)

  • Lee, Jong-Bok;Kim, Do-Jin
    • Journal of Industrial Convergence
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    • v.20 no.8
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    • pp.155-161
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    • 2022
  • The purpose of this study was to investigate the relationship between perfectionism, self-efficacy, and subjective quality of life of rehabilitation trainers. For this purpose, 206 questionnaire results were obtained from rehabilitation trainers working in hospitals and rehabilitation exercise centers located in the metropolitan area. The SPSS statistics were analyzed with the program, and the following results were obtained. First, in the relationship between perfectionism and self-efficacy of rehabilitation trainers, the sub-factor of perfectionism was used as an independent variable and body confidence, which is a sub-factor of self-efficacy, was used as a dependent variable. explained. Second, in the relationship between perfectionism and the physical ability of self-efficacy, self-orientation, people oriented, and social self-confidence were significantly explained. Third, in the relationship between perfectionism and subjective quality of life, subjective quality of life was significantly explained in self-orientation, people orientation, and social loading. Fourth, in the relationship between self-efficacy and subjective quality of life, subjective quality of life was significantly explained in terms of physical ability and body confidence. Through this study, it is judged that the relationship between perfectionism, self-efficacy, and subjective quality of life has a significant relationship, and subsequent research is needed.