The Fabrication of High Energy Flexible Lithium-ion Batteries via Electrode Design

Department of Energy Engineering (Battery Science and Technology)With the advent of flexible electronics, lithium-ion batteries have become a key component of high performance energy storage systems. Thus, considerable effort has been made to keep pace with the development of flexible lithium-ion batteries. To date, many researchers have studied newly designed batteries with flexibility, however, there are several significant challenges needed to be overcome, such as degradation of electrodes under external load, poor battery performance and complicated cell preparation procedures. In addition, in-depth understanding of the current challenges for flexible batteries has been rarely addressed in systematical and practical way. Herein, we review recent progress and current issues for the flexible lithium-ion batteries in terms of battery materials and cell designs. We also provide a critical overview of important issues and challenges for the practical application of flexible lithium-ion batteries. Finally, we discuss the strategies to overcome current limitations towards the practical use of flexible lithium-based batteries, providing the future research directions.ope

Communication over the network of binary switches regulates the activation of A2A_{2A} adenosine receptor

Dynamics and functions of G-protein coupled receptors (GPCRs) are accurately regulated by the type of ligands that bind to the orthosteric or allosteric binding sites. To glean the structural and dynamical origin of ligand-dependent modulation of GPCR activity, we performed total $\sim$ 5 $\mu$sec molecular dynamics simulations of A$_{2A}$ adenosine receptor (A$_{2A}$AR) in its apo, antagonist-bound, and agonist-bound forms in an explicit water and membrane environment, and examined the corresponding dynamics and correlation between the 10 key structural motifs that serve as the allosteric hotspots in intramolecular signaling network. We dubbed these 10 structural motifs "binary switches" as they display molecular interactions that switch between two distinct states. By projecting the receptor dynamics on these binary switches that yield $2^{10}$ microstates, we show that (i) the receptors in apo, antagonist-bound, and agonist-bound states explore vastly different conformational space; (ii) among the three receptor states the apo state explores the broadest range of microstates; (iii) in the presence of the agonist, the active conformation is maintained through coherent couplings among the binary switches; and (iv) to be most specific, our analysis shows that W246, located deep inside the binding cleft, can serve as both an agonist sensor and actuator of ensuing intramolecular signaling for the receptor activation.Finally, our analysis of multiple trajectories generated by inserting an agonist to the apo state underscores that the transition of the receptor from inactive to active form requires the disruption of ionic-lock in the DRY motif.Comment: 28 pages, 17 figure

lessons for Cambodia

Thesis(Master) -- KDI School: Master of Development Policy, 2022A sudden surge of platform delivery workers due to the COVID-19 pandemic has become a global phenomenon; therefore, a social discussion on their protection needs to be urgently addressed. This study aims to analyze the situations of social security systems for platform delivery workers in Korea and Cambodia, mainly focusing on Workers'' Compensation Insurance (WCI) and Employment Insurance (EI). Furthermore, considering the similarity in the WCI structures between Korea and Cambodia, this paper provides policy implications for Cambodia, which still lacks development on social protection for platform delivery workers. This paper is based on recent key literature and interviews with administrators working for WCI and EI to investigate social insurance in Korea and Cambodia. The Korean government has recently executed specific social security policies, through WCI and EI, to protect platform delivery workers. Likewise, there is an active conversation ongoing in Cambodia on the need to protect platform delivery workers, as the nation has a weak policy capacity to build social security systems. Although the Korean case faces some limitations due to their ambiguous labor status and the legal landscape set by traditional labor relationships, the country is making efforts to create a social safety net for all working people. This study expects to give policy implications for Cambodia to establish better social security systems for platform delivery worker using Korea as a model.Ⅰ. Introduction Ⅱ. Research Methods Ⅲ. Literature Review Ⅳ. Findings Ⅴ. Policy Implication & Conclusion ReferencesmasterpublishedYoonji LE

Stringy Unification of Type IIA and IIB Supergravities under N=2 D=10 Supersymmetric Double Field Theory

To the full order in fermions, we construct D=10 type II supersymmetric double field theory. We spell the precise N=2 supersymmetry transformation rules as for 32 supercharges. The constructed action unifies type IIA and IIB supergravities in a manifestly covariant manner with respect to O(10,10) T-duality and a pair of local Lorentz groups, or Spin(1,9) \times Spin(9,1), besides the usual general covariance of supergravities or the generalized diffeomorphism. While the theory is unique, the solutions are twofold. Type IIA and IIB supergravities are identified as two different types of solutions rather than two different theories.Comment: v1) 4+9 pages. v2) 1+26 pages, Unification highlighted. References adde

Link between allosteric signal transduction and functional dynamics in a multi-subunit enzyme: S-adenosylhomocysteine hydrolase

S-adenosylhomocysteine hydrolase (SAHH), a cellular enzyme that plays a key role in methylation reactions including those required for maturation of viral mRNA, is an important drug target in the discovery of antiviral agents. While targeting the active site is a straightforward strategy of enzyme inhibition, evidences of allosteric modulation of active site in many enzymes underscore the molecular origin of signal transduction. Information of co-evolving sequences in SAHH family and the key residues for functional dynamics that can be identified using native topology of the enzyme provide glimpses into how the allosteric signaling network, dispersed over the molecular structure, coordinates intra- and inter-subunit conformational dynamics. To study the link between the allosteric communication and functional dynamics of SAHHs, we performed Brownian dynamics simulations by building a coarse-grained model based on the holo and ligand-bound structures. The simulations of ligand-induced transition revealed that the signal of intra-subunit closure dynamics is transmitted to form inter-subunit contacts, which in turn invoke a precise alignment of active site, followed by the dimer-dimer rotation that compacts the whole tetrameric structure. Further analyses of SAHH dynamics associated with ligand binding provided evidence of both induced fit and population shift mechanisms, and also showed that the transition state ensemble is akin to the ligand-bound state. Besides the formation of enzyme-ligand contacts at the active site, the allosteric couplings from the residues distal to the active site is vital to the enzymatic function.Comment: 35 pages, 14 figures, 3 Table

Determinants of Esports Highlight Viewership: The Case of League of Legends Champions Korea

Studies on esports league demand via new media platforms are limited yet. This paper is the first to identify determinants of esports highlight viewership. Using set-level highlight view count from YouTube, we analyze various determinants to explain view counts. As a result, we found that the number of kills, playoff games, age of video clip, 2nd round games, and 3rd set is positively correlated to view counts. Outcome uncertainty and upset results do not affect view counts. We interpret the results that as highlight clips are released after the game is finished, viewers can know the results when making a decision. Or, relatively short highlight videos reduce opportunity costs for fans and fans do not care about game outcomes much

Efficiency analysis of best management practices under climate change conditions in the So-okcheon watershed, South Korea

Best management practices (BMPs) are widely applied to address water quality degradation issues attributed to non-point source pollutants. The objective of this study was to assess the efficiency of two types of BMPs, vegetation filter strips (VFS) and wetlands, in reducing total nitrogen (TN) and total phosphorus (TP) in a watershed, and to investigate whether the efficiency of the two BMPs is maintained under future climate scenarios by employing the Soil and Water Assessment Tool (SWAT). A set of parameters was calibrated using the SWAT Calibration and Uncertainty Program (SWAT-CUP) to ensure acceptable simulation results. Three BMP scenarios were developed by applying VFS and wetlands individually and in combination. Projected climate data from 18 global circulation models under Shared Socioeconomic Pathways (SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5) were used to depict climate change conditions. VFS demonstrated 18.2% and 22.9% greater reduction efficiency for TN and TP, respectively, relative to wetlands. When the two BMPs were simultaneously applied, the reduction efficiency was even greater than that of single-BMP implementation (by 7.4% for TN and 6.8% for TP compared to VFS alone and by 25.5% for TN and 29.7% for TP compared to wetlands alone). To assess the effect of climate change, the model simulated results for the period of 2021–2,100. The differences in efficiency between the combined BMP scenario and the individual BMPs increased with greater intensity of climate change, especially in the distant future. Therefore, this study supports the effectiveness of nutrient pollution control by applying multiple BMPs rather than by applying individual BMPs. Furthermore, this research underscores the adaptability and reliability of natural-based solutions in mitigating non-point source pollution in a changing climate, which is essential for effective ecological restoration in complex urban-agricultural landscapes. The study provides valuable insights for watershed managers and policymakers seeking effective strategies to combat nutrient pollution in the face of a changing climate within the unique landscape of South Korea

Missed a live match? Determinants of League of Legends Champions Korea highlights viewership

This research aims to explore the determinants of the League of Legends Champions Korea (LCK) highlight views and comment counts. The data of 629 game highlight views and comment counts for seven tournaments were collected from YouTube. The highlight views and comment counts were regressed on a series of before-the-game factors (outcome uncertainty and game quality), after-the-game factors (sum and difference of kills, assists, multiple kills, and upset results), and match-related characteristics (game duration, evening game, and clip recentness). A multi-level least square dummy variable regression was conducted to test the model. Among the before-the-game factors, outcome uncertainty and game quality were significantly associated with highlight views and comment counts. This indicated that fans liked watching games with uncertain outcomes and those involving high-quality teams. Among the after-the-game factors, an upset result was a significant determinant of esports highlight views and comment counts. Thus, fans enjoy watching underdogs win. Finally, the sum of kills and assists only affected view counts, which indicated that fans prefer watching offensive games with more kills and a solo performance rather than teamwork