Individual Charge Research Articles

Dissipative split-charge formalism: Ohm's law, Nyquist noise, and non-contact friction.

The split-charge equilibration method is extended to describe dissipative charge transfer similarly as the Drude model, whereby the complex-valued frequency-dependent dielectric permittivities or conductivities of dielectrics and metals can be mimicked at non-zero frequencies. To demonstrate its feasibility, a resistor-capacitor circuit is simulated using an all-atom representation for the resistor and capacitor. The dynamics reproduce the expected charging process and Nyquist noise, the latter resulting from the thermal voltages acting on individual split charges. The method bears promise to model friction caused by the motion of charged particles past metallic or highly polarizable media.

1/f noise in semiconductors arising from the heterogeneous detrapping process of individual charge carriers

Abstract We propose a model of 1 / f noise in semiconductors based on the drift of individual charge carriers and their interaction with the trapping centers. We assume that the trapping centers are homogeneously distributed in the material. The trapping centers are assumed to be heterogeneous and have unique detrapping rates. We show that uniform detrapping rate distribution emerges as a natural consequence of the vacant trap depths following the Boltzmann distribution, and the detrapping process obeying Arrhenius law. When these laws apply, and if the trapping rate is low in comparison to the maximum detrapping rate, 1 / f noise in the form of Hooge’s relation is recovered. Hooge’s parameter, α H, is shown to be a ratio between the characteristic trapping rate and the maximum detrapping rate. The proposed model implies that 1 / f noise arises from the temporal charge carrier number fluctuations, not from the spatial mobility fluctuations.

Biomedical device powered by triboelectric nanogenerator

Biomedical devices play vital roles in health monitoring. Operability of these devices is hindered by their limited battery life. In vivo monitoring, diagnosis, and treatment have become challenging. The proposed Triboelectric Nanogenerator helps in overcoming the shackles of battery life. This article describes the process involved in the development of a healthcare device powered by triboelectric effect. In this work a contact-separation mode based triboelectric nanogenerator (TENG) has been used to power the device. TENG uses triboelectric phenomenon to transform mechanical energy into electrical energy. A contact-separation mode TENG operates through the interaction of two triboelectric materials. These materials act as an anode and a cathode, respectively, and develop opposite charges when brought into contact. Upon separation, the charged surfaces retain their individual charges, creating a potential difference between the materials. This difference generates an electrostatic field that drives the flow of electrons from one electrode to the other. As the electrons return, the field collapses, and the materials come back into contact, repeating the cycle. The device has been used to power a heart rate monitoring system. Experimental results demonstrate the output performance and long-term durability of the TENG device. Furthermore, future research, challenges and opportunities have been elaborated.

A multi-label legal charge prediction method based on summarization generation

Legal Charge Prediction (LCP) is a task of predicting charge labels for which a criminal should be charged based on the factual case descriptions. In recent years, the advancement of deep learning networks has led to the emergence of effective approaches for LCP through the Fine-tuning of pre-trained language models. While existing methods primarily treat it as multiple binary classifications, excelling in the single charge label given factual case descriptions, they still exhibit substantial room for improvement in multi-label LCP. This is because single-label classification methods do not effecitively deal with the relationship between multiple labels, mainly determining the likelihood of a factual description’s association to each individual charge label. Recognizing the need to enhance the relationship among multi-label charges in Fine-tuning-based discriminative charge prediction, this paper introduces a multi-label LCP method based on summarization generation. This method reconstructs the multi-label classification problem as a summarization generation task, capturing the relationship among multiple labels within the summarization content. Empirical findings from the Chinese legal domain’s CAIL2018 dataset demonstrate the method’s capacity to discern the relationship between multiple legal charge labels with Micro-F1 and Macro-F1 enhancements, compared to the fine-tuning-based approaches.

Quantum Liquids: Emergent Higher-Rank Gauge Theory and Fractons

Fractons emerge from many-body systems, featuring subdimensional particles with restricted mobility. These particles have attracted interest for their roles across disciplines, including topological quantum codes, quantum field theory, emergent gravity, and quantum information. They display unique nonequilibrium behaviors such as nonergodicity and glassy dynamics. This review offers a structured overview of fracton phenomena, especially those of gapless fracton liquids, which enable collective modes similar to gauge fluctuations in Maxwell's electromagnetic framework, yet their phenomena are distinguished by a unique conservation law that restricts the mobility of individual charges and monopoles. We delve into the theoretical basis of three-dimensional (3D) fracton liquids, exploring emergent symmetric tensor gauge theories and their properties. We also discuss the material realization of fracton liquids in Yb-based pyrochlore lattices and other synthetic quantum matter platforms.

Controlling Structure and Morphology of MoS2 via Sulfur Precursor for Optimized Pseudocapacitive Lithium Intercalation Hosts

AbstractMolybdenum disulfide (MoS2)‐based electrode materials can exhibit a pseudocapacitive charge storage mechanism induced by nanosized dimension of the crystalline domains, which is why control over material structure via synthesis conditions is of significance. In this study, we investigate how the use of different sulfide precursors, specifically thiourea (TU), thioacetamide (TAA), and L‐cysteine (LC), during the hydrothermal synthesis of MoS2, affects its physicochemical, and consequently, electrochemical properties. The three materials obtained exhibit distinct morphologies, ranging from micron‐sized architectures (MoS2 TU), to nanosized flakes (MoS2 TAA and LC). While all three synthesized samples exhibit pseudocapacitive Li+ intercalation properties, the capacity retention of the latter two consisting of nanosized flakes is further improved at high cycling rates. The individual charge storage properties are analyzed by operando X‐ray diffraction, dilatometry, and 3D Bode analysis, revealing a correlation between the morphology, porosity, and the electrochemical intercalation behavior of the obtained electrode materials. The results demonstrate a facile strategy to control MoS2 structure and related functionality by choice of hydrothermal synthesis precursors.

Digital Ion Trap Isolation and Mass Analysis of Macromolecular Analytes with Multiply Charged Ion Attachment.

Multiply charged ions produced by electrospray ionization (ESI) of heterogeneous mixtures of macromolecular analytes under native conditions are typically confined to relatively narrow ranges of mass-to-charge (m/z) ratio, often with extensive overlap. This scenario makes charge and mass assignments extremely challenging, particularly when individual charge states are unresolved. An ion/ion reaction strategy involving multiply charged ion attachment (MIA) to the mixture components in a narrow range of m/z can facilitate charge and mass assignment. In MIA operation, multiply charged reagent ions are attached to the analyte ions of opposite polarity to provide large m/z displacements resulting from both large changes in mass and charge. However, charge reduction of the high m/z ions initially generated under native ESI conditions requires the ability to isolate high m/z ions and to analyze even higher m/z product ions. Digital ion trap (DIT) operation offers means for both high m/z ion isolation and high m/z mass analysis, in addition to providing conditions for the reaction of oppositely charged ions. The feasibility of conducting MIA experiments in a DIT that takes advantage of high m/z ion operation is demonstrated here using a tandem 2D-3D DIT instrument. Proof-of-concept MIA experiments with cations derived from β-galactosidase using the 20- charge state of human serum immunoglobulin G (IgG, ∼149 kDa) as the reagent anion are described. MIA experiments involving mixtures of ions derived from the E. coli. ribosome are also described. For example, three components in a mixture of 70S particles (>2.2 MDa) were resolved and assigned with masses and charges following an MIA experiment involving the 20- charge state of human serum IgG.

Rising Costs and Diminishing Surgeon Reimbursement From Primary to Revision Total Hip and Knee Arthroplasty: An Analysis of Medicare Advantage and Commercial Insurance.

Revision total joint arthroplasty (rTJA) is a resource-intensive procedure addressing failed primary total joint hip (total hip arthroplasty [THA]) and knee arthroplasty (total knee arthroplasty [TKA]). Despite predictions of increased demand, reimbursement for rTJA has not kept pace with increasing costs and may be insufficient compared with primary procedures. The study aimed to highlight the diminishing surgeon reimbursement between primary and revision THA (rTHA) and TKA. This study is a retrospective analysis of billing data for primary and rTHA and TKA procedures from a single institution between 2019 and 2022. Insurance claims and charges data were provided by a local affiliate of a major national carrier which includes Medicare Advantage (MA) and commercial patients. Using insurance data, the study evaluates the total surgery costs for primary and rTHA and TKA and the individual charges that make up the total surgery cost. Nine hundred five patients insured by the same carrier, who underwent a primary or rTJA, were identified. Irrespective of MA or commercial insurance, the average surgery cost for a primary THA was $26,043, compared with $53,456 for rTHA. Surgeon reimbursement for primary THA was 20% ($5,323) of the total surgery cost. Despite the doubled surgery cost for rTHA, surgeon reimbursement was 10% ($5,257) of the total surgery cost. Primary TKA surgery costs were $24,489, while revision costs were $43,074. Surgeon reimbursement for primary TKA was 20% ($4,918) of the total surgery cost, while reimbursement for revision TKA was 13% ($5,560). MA reimbursement was markedly lower than commercial reimbursement for primary and revision cases. Despite the higher total costs for rTJA, surgeon reimbursement is disproportionately diminished. The findings highlight the lack of incentive for revision cases. Surgeon reimbursement from MA and commercially insured patients for rTJA remains inadequate. This may limit patient access-to-care, leading to suboptimal outcomes and increased healthcare utilization.

Evidence of contact-induced variability in industrially-fabricated highly-scaled MoS2 FETs

Evidence of microscopic inhomogeneities of the side source/drain contacts in 300 mm wafer integrated MoS2 field-effect transistors is presented. In particular, the presence of a limited number of low Schottky barrier spots through which channel carriers are predominantly injected is demonstrated by the dramatic current changes induced by individual charge traps located near the source contact. Two distinct types of “contact-impacting traps” are identified. Type-1 trap is adjacent to the contact interface and exchanges carriers with the metal. Its impact is only observable when the adjacent contact is the reverse-biased FET source and limits the channel current. Type-2 trap is located in the AlOx gate oxide interlayer, near the source contact, and exchanges carriers with the channel. Its capture/emission time constants exhibit both a gate and drain bias dependence due to the high sensitivity of the contact regions to the applied lateral and vertical fields. Unlike typical channel-impacting oxide traps, both types of reported defects affect the Schottky barrier height and width rather than the threshold voltage and result in giant random telegraph noise (RTN). These observations indicate that the contact quality and geometry play a fundamental role in the ultimate scaling of 2D FETs.

Coupled vertical double quantum dots at single-hole occupancy

Gate-defined quantum dots define an attractive platform for quantum computation and have been used to confine individual charges in a planar array. Here, we demonstrate control over vertical double quantum dots confined in a strained germanium double quantum well. We sense individual charge transitions with a single-hole transistor. The vertical separation between the quantum wells provides a sufficient difference in capacitive coupling to distinguish quantum dots located in the top and bottom quantum wells. Tuning the vertical double quantum dot to the (1,1) charge state confines a single-hole in each quantum well beneath a single plunger gate. By simultaneously accumulating holes under two neighboring plunger gates, we are able to tune to the (1,1,1,1) charge state. These results motivate quantum dot systems that exploit the third dimension, opening new opportunities for quantum simulation and quantum computing.

Role of Charge Heterogeneity on Physical Stability of Monoclonal Antibody Biotherapeutic Products.

Chemical modifications in monoclonal antibodies can change hydrophobicity, charge heterogeneity as well as conformation, which eventually can impact their physical stability. In this study, the effect of the individual charge variants on physical stability and aggregation propensity in two different buffer conditions used during downstream purification was investigated. The charge variants were separated using semi-preparative cation exchange chromatography and buffer exchanged in the two buffers with pH 6.0 and 3.8. Subsequently each variant was analysed for size heterogeneity using size exclusion chromatography and dynamic light scattering, conformational stability, colloidal stability, and aggregation behaviour under accelerated stability conditions. Size variants in each charge variant were similar in both pH conditions when analyzed without extended storage. However, conformational stability was lower at pH 3.8 than pH 6.0. All charge variants showed similar apparent melting temperature at pH 6.0. In contrast, at pH 3.8 variants A3, A5, B2, B3 and B4 display lower Tm, suggesting reduced conformational stability. Further, A2, A3 and A5 exhibit reduced colloidal stability at pH 3.8. In general, acidic variants are more prone to aggregation than basic variants. Typical industry practice today is to examine in-process intermediate stability with acidic species and basic species taken as a single category each. We suggest that perhaps stability evaluation needs to be performed at specie level as different acidic or basic species have different stability and this knowledge can be used for clever designing of the downstream process to achieve a stable product.

Optimization of Quantum Nuclei Positions with the Adaptive Nuclear-Electronic Orbital Approach.

The use of multicomponent methods has become increasingly popular over the last years. Under this framework, nuclei (commonly protons) are treated quantum mechanically on the same footing as the electronic structure problem. Under the use of atomic-centered orbitals, this can lead to some complications as the ideal location of the nuclear basis centers must be optimized. In this contribution, we propose a straightforward approach to determine the position of such centers within the self-consistent cycle of a multicomponent calculation, making use of individual proton charge centroids. We test the method on model systems including the water dimer, a protonated water tetramer, and a porphine system. Comparing to numerical gradient calculations, the adaptive nuclear-electronic orbital (NEO) procedure is able to converge the basis centers to within a few cents of an Ångström and with less than 0.1 kcal/mol differences in absolute energies. This is achieved in one single calculation and with a small added computational effort of up to 80% compared to a regular NEO- self-consistent field run. An example application for the human transketolase proton wire is also provided.

Ion emission from 1-10 MDa salt clusters: individual charge state resolution with charge detection mass spectrometry.

Salt cluster ions produced by electrospray ionization are used for mass calibration and fundamental investigations into cluster stability and charge separation processes. However, previous studies have been limited to relatively small clusters owing to the heterogeneity associated with large, multiply-charged clusters that leads to unresolved signals in conventional m/z spectra. Here, charge detection mass spectrometry is used to measure both the mass and charge distributions of positively charged clusters of KCl, CaCl2, and LaCl3 with masses between ∼1 and 10 MDa by dynamically measuring the energy per charge, m/z, charge, and mass of simultaneously trapped individual ions throughout a 1 s trapping time. The extent of remaining hydration on the clusters, determined from the change in the frequency of ion motion with time as a result of residual water loss, follows the order KCl < CaCl2 < LaCl3, and is significantly lower than that of a pure water nanodrop, consistent with tighter water binding to the more highly charged cations in these clusters. The number of ion emission events from these clusters also follows this same trend, indicating that water at the cluster surface facilitates charge loss. A new frequency-based method to determine the magnitude of the charge loss resulting from individual ion emission events clearly resolves losses of +1 and +2 ions. Achieving this individual charge state resolution for ion emission events is an important advance in obtaining information about the late stages of bare gaseous ions formation. Future experiments on more hydrated clusters are expected to lead to a better understanding of ion formation in electrospray ionization.

A machine learning framework for remaining useful lifetime prediction of li-ion batteries using diverse neural networks

Accurate prediction of the remaining useful life (RUL) of lithium-ion batteries (LIBs) is pivotal for enhancing their operational efficiency and safety in diverse applications. Beyond operational advantages, precise RUL predictions can also expedite advancements in cell design and fast-charging methodologies, thereby reducing cycle testing durations. Despite artificial neural networks (ANNs) showing promise in this domain, determining the best-fit architecture across varied datasets and optimization approaches remains challenging. This study introduces a machine learning framework for systematically evaluating multiple ANN architectures. Using only 30% of a training dataset derived from 124 LIBs subjected to various charging regimes, an extensive evaluation is conducted across 7 ANN architectures. Each architecture is optimized in terms of hyperparameters using this framework, a process that spans 145 days on an NVIDIA GeForce RTX 4090 GPU. By optimizing each model to its best configuration, a fair and standardized basis for comparing their RUL predictions is established. The research also examines the impact of different cycling windows on predictive accuracy. Using a stratified partitioning technique underscores the significance of consistent dataset representation across subsets. Significantly, using only the features derived from individual charge–discharge cycles, our top-performing model, based on data from just 40 cycles, achieves a mean absolute percentage error of 10.7%.

Synergistic Interaction of Hyperbranched Polyglycerols and Cetyltrimethylammonium Bromide for Oil/Water Interfacial Tension Reduction: A Molecular Dynamics Study.

Applying surfactants to reduce the interfacial tension (IFT) on water/oil interfaces is a proven technique. The search for new surfactants and delivery strategies is an ongoing research area with applications in many fields such as drug delivery through nanoemulsions and enhanced oil recovery. Experimentally, the combination of hyperbranched polyglycerol (HPG) with cetyltrimethylammonium bromide (CTAB) substantially reduced the observed IFT of oil/water interface, 0.9 mN/m, while HPG alone was 5.80 mN/m and CTAB alone IFT was 8.08 mN/m. Previous simulations in an aqueous solution showed that HPG is a surfactant carrier. Complementarily, in this work, we performed classical molecular dynamics simulations on combinations of CTAB and HPG with one aliphatic chain to investigate further the interaction of this pair in oil interfaces and propose the mechanism of IFT decrease. Basically, from our results, one can observe that the IFT reduction comes from a combination of effects that have not been observed for other dual systems: (i) Due to the CTAB-HPG strong interaction, a weakening of their specific and isolated interactions with the water and oil phases occurs. (ii) Aggregates enlarge the interfacial area, turning it into a less ordered interface. (iii) The spread of individual molecules charge profiles leads to the much lower interfacial tension observed with the CTAB+HPG systems.

취락지구가 연립주택 가격에 미치는 영향

In this study, the effect of settlement district on the price and price increase rate of the row houses in Jeju-do was analyzed.&#x0D; In the price determinants of row houses, the larger the area of exclusive use space and the higher the living floor, the higher the price, and the lower the price over time. The total floor area of the row house complex and the number of parking spaces per household have a positive effect on the price, and the larger the remaining building-to-land ratio, the lower the price. The price of row houses in Seogwipo-si is higher than that of Jeju-si, the price of row houses in the settlement district is higher than that of non-settlement district, and there is a price difference depending on the adjacent road.&#x0D; In the price increase determinants of row houses, the area of exclusive use space did not affect the price increase, and the longer the construction is completed, the larger the total floor area, and the higher the number of parking per household, the higher the price increase rate. There was no difference between Jeju-si and Seogwipo-si in terms of price increase determinants, and row houses in the settlement district had a higher price increase rate than non-settlement district, and adjacent road did not affect the price increase rate.&#x0D; Through the results of this study, it is necessary to review the reflection of the price magnification for the settlement district when calculating individual land prices and development charges. In addition, row house consumers need to check whether it is a settlement district.

Direct measurements of cosmic rays with the calorimetric electron telescope on the international space station

The CALorimetric Electron Telescope, CALET, has been measuring high-energy cosmic rays on the International Space Station since October 13, 2015. The scientific objectives addressed by the mission are to search for possible nearby sources of high-energy electrons and potential signatures of dark matter, and to investigate the details of galactic cosmic-ray acceleration and propagation. The calorimetric instrument, which is 30 radiation lengths or 1.3 proton interaction lengths thick with fine imaging capability, is optimized to measure cosmic-ray electrons by achieving large proton rejection and excellent energy resolution well into the TeV region. In addition, very wide dynamic range of energy measurement and individual charge identification capability enable us to measure proton and nuclei spectra from a few tens GeV to a PeV scale. Nearly 20 million cosmic-ray shower events over 10 GeV per month are triggered and the continuous observation has been kept without any major interruption since the start of operation. Using the data obtained over 6.5 years of operation, we will present a brief summary of the CALET observation including electron spectrum, and proton and nuclei spectra as well as the performance study on orbit with MC simulations.

Investigation of active cell balancing performance for series connected lithium‐ion cells in electric vehicle applications

AbstractLithium‐ion batteries have a very wide application range. They can power up small electronic devices such as smart watches to larger electric vehicles. Due to its varied range of applications, they come in different packaging and in such battery packs, even when individual cell voltage exceeds by a few milli‐volts above 4.2 V, it may result in thermal runaway and explode the cell. During discharge cycle, cell imbalances hinder the use of battery to its full capacity. This in turn decreases the battery lifetime. The individual battery cells should be equalized on a regular basis to keep the imbalances to a minimum and to have a good battery life. The process of balancing the individual cell charges by measuring the cell state of charge (SoC) and its voltage in a battery pack is known as cell balancing. This paper details an active cell balancing technique that uses a buck converter for balancing a series connected battery pack of lithium‐ion cells. A buck converter along with a pair of MOSFET switches for each cell, one turned on for charging the cell and the other one turned on while discharging the cell is used in this experiment. An algorithmic model suitable for reconfigurable battery systems that measures the individual cell voltages and is developed for balancing a pack of series connected Li‐ion battery cells. The developed model is simulated using MATLAB for verifying its performance. A state of charge of 25% is maintained across the cells and when SoC value drops below this even a difference of 0.02% is sensed by the algorithm to initiate balancing function. This balancing is found to take 275 ms to balance three 3.7 V batteries and thus the model is found to respond faster. The results show that this method can self‐adaptively attain satisfactory performance within a limited equalizing period.

New approach to instantaneous polarizable electrostatic embedding of the solvent

The sequential quantum mechanics/molecular mechanics (S-QM/MM) method efficiently computes solvent effects on the electronic properties of solutes. The protocol involves two steps: solute-solvent configurations are generated from MM simulations, while the solute properties are computed in the subsequent QM step. A well-known difficulty within the S-QM/MM framework is the description of the polarization of the MM partition (electrostatic embedding) in case the electronic structure of the solute undergoes sudden changes, such as in electronic excitation, electron attachment or detachment processes. To improve the description of the electronic polarization of the solvent, we propose the self-consistent S-QM/MM polarizable electrostatic embedding (scPEE-S-QM/MM) method, which generates individual atomic charges for the solvent molecules due to solute-solvent and solvent-solvent polarization. The electronic properties calculated for the neutral and anion states of 1-methyl-4-nitroimidazole were found to be significantly affected by solvent polarized electrostatic embeddings obtained for different solute electronic states. Finally, the method also provides accurate results for bulk water.

Dependence of ion charge-energy emission from Nd:YAG-laser-produced plasma on laser intensity in the 0.4–40×1010 W/cm2 range

We experimentally characterize the ionic emission, including the individual charge states Snz+ (z=1, …, 8), from laser-produced tin plasma as a function of the intensity of the employed ns-pulsed laser. The plasma is generated in a vacuum from tin microdroplets (diameter ranging from 17 to 35 μm) using pulsed Nd:YAG laser light (laser wavelength λ=1.064 μm) over a range of intensities (0.4–40×1010 W/cm2). We measure charge-state-resolved and integrated ion energy distributions at seven angular positions around the plasma using seven retarding field analyzers. We highlight peak features in both types of spectra and describe the dependence of their energies on laser intensity with power-law functions. The resulting power laws match those derived from plasma radiation hydrodynamics theory. The analytical scaling laws exhibit strong isotropy, while the ion energy spectra are highly anisotropic.