• 청정기술
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• 제26권4호
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• pp.257-262
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• 2020

Two-dimensional (2D) metal organic framework (MOF) nanosheets (NSs) have recently gained considerable interest owing to their structural advantages, such as large surface area and exposed active sites. Two different types of 2D MOF NSs have been reported, including inherently layered MOFs and non-layered ones. Although several studies on inherently layered 2D MOFs have been reported, non-layered 2D MOFs have been rarely studied. This may be because the non-layered MOFs have a strong preference to form three-dimensionality intrinsically. Furthermore, the non-layered MOFs are typically synthesized in the presence of the surfactant or modulator, and thus developing facile and clean synthetic routes is highly pursued. In this study, a facile and clean synthetic methodology to grow non-layered 2D cobalt-based zeolitic imidazolate framework (ZIF-67) NSs is suggested, without using any surfactant and modulator at room temperature. This is achieved by directly converting ultrathin α-Co(OH)2 layered hydroxide salt (LHS) NSs into non-layered 2D ZIF-67 NSs. The comprehensive characterizations were conducted to elucidate the conversion mechanism, structural information, thermal stability, and chemical composition of the non-layered 2D ZIF-67. This facile and clean approach could produce a variety of non-layered 2D MOF NS families to extend potential applications of MOF materials.

• 한국IT서비스학회지
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• 제20권5호
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• pp.177-187
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• 2021

The global economy has been very difficult due to the recent impact of COVID-19. Korea is also pushing for strong quarantine policies such as K- quarantine and social distancing, but the economy is hardly recovering. In particular, the economic situation began to change rapidly depending on the export and domestic market, the public's interest in the economy increased, and companies became more sensitive. In order to estimate this rapidly changing economic situation, major advanced countries have also developed models that can periodically monitor the economy at the government level. Through this, by periodically reporting the economic trends, the public and companies can be aware of the economic trends to some extent. This study analyzed the cases of weekly business trends in advanced countries and developed a model of weekly economic activity suitable for Korea. To verify this, indices closely related to the economy such as mobility, industrial activity, face-to-face consumption, and psychology were discovered and estimated. As a result of the study, the weekly economic activity index was judged to be very useful in capturing short-term real economic activity. In the future, in order to secure the robustness and stability of the index and to increase the reflection of reality, model improvement and parameter estimation should be performed regularly.

• International Journal of Advanced Culture Technology
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• 제9권4호
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• pp.226-236
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• 2021

The purpose of this study is to analyze the type of latent profile for general high school students' subject selection criteria and to identify the characteristics of the latent class. The survey data of 1072 general high school students (male; 648, female; 424) in G city, Jeollabuk-do and the scale composed of 8 sub-factors: 'SAT orientation', 'academic achievement', 'ability orientation', 'pursuit of interest', 'teacher orientation', 'career development', 'others' recommendation', and 'subject availability' were used for latent profile analysis and cross-analysis between potential layers. As a result of the analysis, high school students' perceptions of subject selection were classified into four latent profiles. The four groups were named 'High Perception Type', 'Low Perception Type', 'Self-Directed Type', and 'Stability-Oriented Type' according to their types. It was found that there was a difference between the latent classes in the importance and performance level of the subject selection criteria. These results can help identify the subject selection tendencies of latent groups in the operation of the 2015 revised curriculum and the 2025 high school credit system that emphasizes the student-centered course selection curriculum and they can also provide customized course selection guidance considering individual differences.

• Corrosion Science and Technology
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• 제21권4호
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• pp.300-313
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• 2022

Interest in polymer electrolyte fuel cell is growing to replace fossil fuels. In particular, in order to reduce the cost and volume of the fuel cell, research on a metallic bipolar plate is being actively conducted. In this research, investigated the effects of temperature and chloride concentration on the electrochemical characteristics and damage behavior of 316L stainless steel in an accelerated solution simulating the cathodic operating condition of PEMFC(Polymer electrolyte membrane fuel cell). As a result of the experiments, the corrosion current density, damage size, and surface roughness increased as the temperature and chloride concentration increased. In particular, the temperature had a significant effect on the stability of the oxide film of 316L stainless steel. In addition, it was described that the growth of the pit was affected by the chloride concentration rather than the temperature. As a result of calculating the corrosion tendency to compare the pitting corrosion rate and the uniform corrosion rate, the uniform corrosion tendency became larger as the temperature increased. And the effects of chloride concentration on corrosion tendency was different according to temperature.

• 한국작물학회지
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• 제33권s01호
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• pp.64-85
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• 1988

Peanut seeds are characterized by high oils and proteins with good quality, and are utilized as an edible oil source and a protein-rich food products. The end products, being peanut butter, salted seed, confections, roasting stock and other by-products are favored in world-wide because of their unique roasted peanut flavor. As with many other foods, interest in the composition and chemistry of peanut is largely a result of thier use as human food. Thus, a more complete knowledge of thier chemical and food quality and flavor properties is desired. Literatures are reviewed mainly focucing on the physicochemical properties and nutritional quality of oil, protein and flavor in peanuts. Chemical properties of protein and oil, and volatile flavor component in peanut seeds are studied extensively in view point of chemical and food nutritional value. But in crop base, the synthesis and genetic studies of the chemicals could not provide valuable informations on the breeding for quality improvement. Some essential amino acids are limiting in peanut seeds and the tocopherols are very important in oil stability and for dietary adequacy ratio in high linoleic acid peanut oil, but it is thought to be quite difficult to improve by breeding technique as their lack information of gene actions. However, the selections of high protein and oil, and some essential amino acids and linoleic acid rich genotypes could be helpful for the quality improving. Research studies are also needed to elucidate the relationships between flavor components and consumer perception of peanut flavor.

• 한국분말재료학회지
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• 제30권4호
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• pp.310-317
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• 2023

Small-film-type ion sensors are garnering considerable interest in the fields of wearable healthcare and home-based monitoring systems. The performance of these sensors primarily relies on electrode capacitance, often employing nanocomposite materials composed of nano- and sub-micrometer particles. Traditional techniques for enhancing capacitance involve the creation of nanoparticles on film electrodes, which require cost-intensive and complex chemical synthesis processes, followed by additional coating optimization. In this study, we introduce a simple one-step electrochemical method for fabricating gold nanoparticles on a carbon nanotube (Au NP-CNT) electrode surface through cyclic voltammetry deposition. Furthermore, we assess the improvement in capacitance by distinguishing between the electrical double-layer capacitance and diffusion-controlled capacitance, thereby clarifying the principles underpinning the material design. The Au NP-CNT electrode maintains its stability and sensitivity for up to 50 d, signifying its potential for advanced ion sensing. Additionally, integration with a mobile wireless data system highlights the versatility of the sensor for health applications.

• 한국축산식품학회지
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• 제42권2호
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• pp.197-209
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• 2022

Extracellular vesicles (EVs) are nanosized vesicles secreted from cells into the extracellular environment and are composed of a lipid bilayer that contains cargos with biological activity, such as lipids, proteins, mRNAs, and noncoding microRNAs (miRNAs). Due to their biological activity and their role in cell-to-cell communication, interest in EVs is rapidly increasing. Bovine milk is a food consumed by people of all ages around the world that contains not only a significant amount of nutrients but also EVs. Milk-derived EVs also exhibit biological activity similar to other source-derived EVs, and studies on bovine milk EVs have been conducted in various research fields regarding sufficient milk production. In particular, not only are the effects of milk EVs themselves being studied, but the possibility of using them as drug carriers or biomarkers is also being studied. In this review, the characteristics and cargo of milk EVs are summarized, as well as their uptake and stability, efficacy and biological effects as carriers, and future research directions are presented.

• Steel and Composite Structures
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• 제42권5호
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• pp.591-598
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• 2022

The article deals with the possibilities of vibration stimulation. Based on the stability analysis, a multi-scale approach with a modified whole-building model is implemented. The motion equation is configured for a controlled bridge with a MDOF (multiple dynamic degrees of freedom) Tuned Mass Damper (M-TMD) system, and a combination of welding, excitation, and control effects is used with its advanced packages and commercial software submodel. Because the design of high-performance and efficient structural systems has been of interest to practical engineers, systematic methods of structural and functional synthesis of control systems must be used in many applications. The smart method can be stabilized by properly controlling the high frequency injection limits. The simulation results illustrate that the multiple modeling method used is consistent with the accuracy and high computational efficiency. The M-TMD system, even with moderate reductions in critical pressure, can significantly suppress overall feedback on an unregulated design.

• 한국정보시스템학회지:정보시스템연구
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• 제32권2호
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• pp.153-176
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• 2023

Purpose As non-face-to-face work environments become common due to COVID-19, interest in online collaboration tools that can communicate smoothly without time and space limitations is continuously increasing. Most of the prior studies are about the introduction, use intention, and satisfaction of cloud computing-based collaboration tools, and studies on the effects of collaboration tools on work-life balance and quality of life are somewhat lacking. Therefore, in this study, the characteristics of cloud computing-based collaboration tools were derived, and the effect on job satisfaction during work and job stress outside of working hours was confirmed. Design/methodology/approach This study applied the S-O-R framework and conducted an online survey of office workers who used cloud computing-based collaboration tools for more than three months. Hypotheses were tested using structural equations. Findings As a result of the analysis, among the characteristics of collaboration tools, stability, usefulness, and interoperability had higher job satisfaction as more stimuli were applied. In addition, the higher the job satisfaction during work, the higher the job performance, work-life balance, and quality of life.

• 무역학회지
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• 제47권2호
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• pp.89-101
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• 2022

International remittances play a crucial role in the economic management of each country, especially in developing countries. Its functions are diverse, including procurement of foreign currency, serving as a cushion for the balance of payments and foreign exchange reserves by reducing the adverse external shocks, driving economic growth, easing the gap between the rich and the poor, and maintaining macroeconomic stability. However, previous studies on remittances have mainly focused on macro-and micro-economic aspects to analyze the determinants. Therefore, this study attempts to identify the determinants of remittances in 122 countries over the past 25 years from macroeconomic and educational aspects as well as institutional qualities. In addition, given the fact that almost all of the world's top 10 recipient countries in terms of GDP and total remittance size are developing countries, developed and developing countries are separated and analyzed for comparison, assuming that there may be a difference between the two groups. Results show that the coefficients of developed and developing countries are different in four areas: Control of Corruption (CC), Rule of Law (RL), Voice and Accountability (VA), and Regulatory Quality (RQ) among the six institutional variables of interest in this study. These results implicate that even the same institutions and policies should be applied and implemented differently depending on the circumstances of each country. In addition, as suggested by the World Bank, policymakers in all countries should double their policy efforts to lower the costs of remittance and improve access to the financial system for immigrants or dispatched workers to ensure a steady inflow of remittances.