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Hierarchically Porous Polyaniline Exhibiting Enhanced Pseudocapacitive Property from Copolymerization of Aniline and Tetrakis(4-aminophenyl)methane
No full textHierarchically porous polyaniline (PANI) was synthesized by oxidative copolymerization of tetrakis(4-aminophenyl)methane (TA) and aniline. Mixing TA with ammonium persulfate (APS) followed by aniline addition generated both tetra-arm star-shaped and linear PANIs; their insolubility in the reaction medium led to aggregation into solid precipitates. During assembly, linear PANI formed nanofibers, while star-shaped PANI created short branches on the nanofiber surfaces. The TA molar fraction in the feed governed morphology and properties: higher TA increased specific surface area and the mesopore fraction but decreased electrical conductivity. Balancing this porosity–conductivity trade-off identified PANI (TA 3%) as optimal, exhibiting the highest CV current response with pseudocapacitive profiles, with a specific capacitance of 556 F g−1 versus 380 F g−1 for pristine PANI. Device-level galvanostatic charge–discharge yielded 239 F g−1 at 0.1 A g−1 (vs. 199 F g−1), while high-rate performance was limited by conductivity. These results show that introducing a small comonomer fraction to promote star-chain growth can produce hierarchical porosity and enhance pseudocapacitive behavior; further conductivity enhancement is expected to improve high-rate capacitance. © 2025 by the authors.TRUEsciescopu
Application of the DTW-N Method for Analyzing Similarity Between EEG Signals
No full textAlthough Euclidean Distance (ED) has limitations in fully capturing the inherent similarity between sig- nals, it has demonstrated higher accuracy in personal identification than Dynamic Time Warping (DTW) when applied in Electroencephalogram (EEG) signal-based authentication systems. In this study, we aim to compare the perfor- mance of ED, DTW, and DTW-Normalization (DTW-N) algorithms in assessing EEG signal similarity. Furthermore, this study evaluates the effects of normalization on similarity measurement across different channels, participants, and signal counts. EEG data were collected from ten participants during speech tasks with auditory stimuli, and all 32 EEG channels were analyzed. The is an indicator used to quantitatively evaluate the difference between signals from the same subject and different subjects; a higher value indicates a greater difference in signal similarity. DTW- N achieved the highest values compared to ED and DTW. Across all channels, DTW-N showed the highest values, with the FC1 channel having the highest average DTW-N value of 3.4110 × 10-2. Additionally, for participants 3 and 9 reached 4.7225 × 10 , approximately 55.79% higher than the DTW-N mean, while for participants 7 and 8 -5 was the lowest at 4.7225 × 10-5. As the number of signals increased, the values decreased. The DTW-N algorithm effectively addressed temporal distortion and amplitude variations in EEG signals, making it highly effective for dis- tinguishing individuals based on EEG patterns. Future research will explore optimal representative metrics for EEG data and enhance individual identification performance using DTW-N-based classification modelsFALSEkc
Selective Lithium Separation Using UiO-66@PIM-1 Mixed Matrix Membranes in Electrochemical System
No full textDisturbance-Observer-Based Virtual Impedance for Virtual Synchronous Generators
No full textThis paper proposes a novel method for implementing a virtual impedance (VI) based on a disturbance observer (DOB) in the virtual synchronous generator (VSG). In conventional methods, the emulation performance of VI can be impeded by rough approximation or control interactions. In addition, the implementation of VI needs to be carefully designed to prevent instability under weak grid conditions and compensate for nonlinear distortions of inverters. The DOB-based VI utilizes a complete impedance model without the approximation, leading to an accurate emulation of VI. Above all, a target impedance can be conveniently adjusted by simply setting the nominal parameters of the plant model for the DOB, even if the actual parameters are inaccurately known. Additionally, the proposed method enhances the accuracy of impedance emulation by improving the VSG's ability to reject unmodeled disturbances, such as voltage distortion caused by the dead-time effect. The characteristics of the proposed method are examined using comparative analyses against conventional methods, based on eigenvalue trajectories and frequency responses. Finally, the effectiveness of the proposed method is validated with simulation and experimental results. © 1972-2012 IEEE.FALSEsciescopu
Revealing the Impact of Aggregations in the Graph-Based Molecular Machine Learning: Electrostatic Interaction Versus Pooling Methods
No full textMolecular structures that can be readily represented by graphs comprising constituent atoms (nodes) and their chemical bonds (edges) can also be used as input data for well-known machine learning (ML) models that process this data, such as graph neural networks (GNNs). GNNs have shown a reasonable performance in the predicting properties of chemical systems. In typical applications of GNNs to chemistry-related fields, the main objective is to create an optimal molecular representation by aggregating atomic features and pooling features in the graph. In this study, two different approaches are investigated that can possibly generate better molecular representations. First, intermolecular edges are created to predict the photochemical properties of chromophore molecules in the solution. These intermolecular edges are constructed using atomic partial charges, inspired from the fact that electrostatic interaction is the main component of solute-solvent interaction. In the second approach, the effect of the aggregation and pooling functions is investigated. The results show that intermolecular electrostatic edges based on ground state charges prevent the GNN model from generating more effective molecular representations. On the contrary, the model demonstrated better performance when the averaging and adding operations are employed in a hybrid manner for the aggregation and pooling functions.FALSEsciescopu
A Review on Vehicle-Grid-Integration Development in South Korea
No full textThe uncertainty in demand and supply in the power grid due to the widespread adoption of renewable energy resources is a significant concern. Electric vehicles (EVs) can be utilized as resources to mitigate the concern. However, to apply these resources, it is necessary to verify their suitability, resource potential, and economic impact. Therefore, this study analyzes how EVs can be utilized as resources and proposes a pilot project for operating smart charging (V1G) of EVs in South Korea. This pilot project includes experiments performing V1G in response to Demand Response (DR) signals and surveys to determine EV users' pReferences for V1G participation. Additionally, an analysis of charging characteristics was conducted because resource potential depends on EV users' charging behaviors. The experimental results confirmed the technical value of EVs as resources. However, the economic analysis revealed that there is no economic benefit for V1G operators, making V1G implementation difficult under the current system. Finally, meaningful suggestions are provided for the application and activation of EVs as resources.TRUEsciescopu
Neustonic zooplankton communities across distinct summer water masses in the northern East China Sea
No full textMarine neustonic zooplankton are subject to extreme fluctuations in environmental conditions, including water temperature, salinity, and ocean currents. This study examined the community structure of neustonic zooplankton, focusing on copepods, across distinct continental shelf water masses in the northern East China Sea, where coastal and oceanic waters converge. Neustonic zooplankton samples were collected using a neuston net from three regions surrounding Jeju Island, Korea, during June, August, and September 2021. Environmental parameters, such as water temperature, salinity, size-fractioned chlorophyll a concentrations, and suspended particulate matter, were measured. The neustonic copepod community in each region was categorized into two groups based on water masses: Yangtze River Diluted Water (YRDW) versus the remaining shelf water in June; YRDW versus Tsushima Warm Current (TWC) in August; and mixed waters (South Korean Coastal Water, SKCW) versus TWC in September. The spatial distribution of neustonic zooplankton was primarily influenced by distinct water masses. Coastal indicator species (Paracalanus parvus sensu lato (s. l.), Labidocera rotunda, and Ditrichocorycaeus affinis) were significantly correlated with chlorophyll a concentrations in YRDW and SKCW, conversely, water temperature and salinity were closely associated with the abundance of high-salinity indicator species (Canthocalanus pauper, Temora discaudata, Centropages furcatus, and Undinula vulgaris) in the TWC. Additionally, oceanic indicator species correlated with multiple environmental factors across all water masses. These findings suggest that, during summer, the inflow of YRDW influences the spatial conditions in the study area. Moreover, indicator species can serve as valuable markers of water mass fluctuations. © 2025 Elsevier LtdFALSEsciescopu
Estimation of Gait Phase of Human Stair Descent Walking Based on Phase Variable Approach
No full textSynchronization between a wearer and a lower limb powered prosthesis is important for effective control. Typically, phase variable-based phase estimation methods are employed. However, there is a noticeable lack of studies focusing on estimating the gait phase during stair descent, likely due to the difficulty in generating a reliable phase variable. In most studies, the thigh angle is used to generate phase variables for level walking because it follows a sinusoidal pattern. However, during stair descent, the thigh angle exhibits only a partially sinusoidal shape, making it challenging to apply the methods used for level walking. In this study, we propose a novel phase variable generation method to address the difficulty of using only the thigh angle for stair descent. To estimate the gait phase reliably, the phase variable is defined differently for the stance and swing phases: the hip position is used to generate the phase variable during the stance phase, and the thigh angle is used during the swing phase. These phase variables are then unified into a single phase variable (PV-ENT) for the entire gait cycle of stair descent. During this unification process, a non-smooth transition occurs around the phase transition point. To address this, a blending method is applied. The proposed method was validated using the data from 12 healthy subjects, collected through a motion capture system and IMU sensors. The results demonstrate a reliable phase estimation performance. Moreover, the blending method successfully improves the smoothness of the phase variable around the phase transition point without reducing the overall phase estimation performance. © 2016 IEEE.FALSEsciescopu
Structural and functional studies of human porphyrin transporter ABCB6 and Aeribacillus pallidus γ-carbonic anhydrase
No full textPart I: Structural and functional analysis of human porphyrin transporter ABCB6 using cryo electron microscopy
ATP-binding cassette transporter B6 (ABCB6), a protein essential for heme biosynthesis in mitochondria, also functions as a heavy metal efflux pump. Here, I present cryo-electron microscopy structures of human ABCB6 bound to a cadmium Cd(II) ion in the presence of antioxidant thiol peptides glutathione (GSH) and phytochelatin 2 (PC2) at resolutions of 3.2 and 3.1 Å, respectively. The overall folding of the two structures resembles the inward-facing apo state but with less separation between the two halves of the transporter. Two GSH molecules are symmetrically bound to the Cd(II) ion in a bent conformation, with the central cysteine protruding towards the metal. The N-terminal glutamate and C-terminal glycine of GSH do not directly interact with Cd(II) but contribute to neutralizing positive charges of the binding cavity by forming hydrogen bonds and van der Waals interactions with nearby residues. In the presence of PC2, Cd(II) binding to ABCB6 is similar to that observed with GSH, except that two cysteine residues of each PC2 molecule participate in Cd(II) coordination to form a tetrathiolate. Structural comparison of human ABCB6 and its homologous Atm-type transporters indicate that their distinct substrate specificity might be attributed to variations in the capping residues situated at the top of the substrate-binding cavity.|Part II: Crystal structure of γ-carbonic anhydrase from the polyextremophilic bacterium Aeribacillus pallidus
The polyextremophilic bacterium Aeribacillus pallidus produces a thermo- and alkali-stable γ-carbonic anhydrase (γ-apCA), a homotrimeric metalloenzyme containing a zinc ion in its active site that catalyzes the reversible hydration of carbon dioxide (CO2). In this study, I determined the first crystal structure of γ-apCA at 1.7 Å resolution, revealing two trimers in the asymmetric unit. The overall structure is consistent with other γ-CAs, where each monomer adopts a prism-like structure consisting of an N-terminal left-handed β-helix and a C-terminal α-helix. The active site, located at the interface between two monomers, coordinates the zinc ion with three histidine residues (H65, H82, and H87) and a water molecule in a tetrahedral configuration. Structural comparison indicates that the amino acid composition at the active site of γ-apCA differs significantly from the prototypic γ-CA from Methanosarcina thermophila. This variation likely accounts for the lack of measurable CO2 hydration activity in γ-apCA. Additionally, the structure reveals non-catalytic zinc and sulfate ions trapped at the trimer core and trimer-trimer non-crystallographic interfaces. These may contribute to stabilizing enzyme assembly and promoting crystal packing.DoctorI. Introduction 2
II. Materials and Methods 5
2.1. Cloning, protein expression, and purification 5
2.2. Nanodisc reconstruction 6
2.3. ATPase assay 7
2.4. Microscale thermophoresis assay 8
2.5. Cytotoxicity assay 8
2.6. Cryo-EM sample preparation and data acquisition 9
2.7. Cryo-EM data processing 10
2.8. Model building and refinement 15
2.9. Statistical analysis 16
III. Results 17
3.1. Binding of cadmium to hABCB6core significantly enhances ATPase activity in the presence of GSH 17
3.2. Structure determination 22
3.3. Overall folds 25
3.4. Cd(II) ion-binding site 29
3.5. Structural comparison with the Atm family 33
IV. Discussion 36
V. References 42
VI. Summary in Korean 52
Part II: Crystal structure of γ-carbonic anhydrase from the polyextremophilic bacterium Aeribacillus pallidus
I. Introduction 54
II. Materials and Methods 57
2.1. Cloning, protein expression, and purification 57
2.2. CO2 hydration assay 57
2.3. Crystallization, X-ray diffraction data collection, and structure determination 58
III. Results 61
3.1. CO2 hydration activity 61
3.2. Overall structure 62
3.3. Active site 65
3.4. Non-catalytic zinc and sulfate ions at the interface between subunits. 67
IV. Discussion 70
V. References 72
VI. Summary in Korean 79
VII. Acknowledgement 8
Laser-plasma-based radiation sources with intense laser pulses
No full textLaser–plasma interactions with ultra-intense lasers yield a variety of particle and radiation sources. Compared to synchrotron facilities, which provide short-wavelength, high-brilliance sources, laser–plasma sources offer a compact and cost-effective alternative. These sources can produce electromagnetic radiation spanning from radio frequencies to gamma-rays. In this review, we explore diverse schemes of laser–plasma-based radiations, including Bremsstrahlung, characteristic X-rays, X-ray lasers, high-order harmonic generation, betatron radiation, inverse Compton scattering, laser–plasma THz sources, and other recently developed radiation sources based on laser–plasma interactions. The versatility of radiation sources from laser–plasma interactions makes them valuable for applications in fields such as biomedical science, material science, nuclear physics, non-destructive inspection technologies, and semiconductor technologies. © Division of Plasma Physics, Association of Asia Pacific Physical Societies 2025.FALSEscopu