bluuebunny/crossref_metadata_2025 huggingface dataset:
Detection of cyber attacks on IoT based cyber physical systems
Authors: Anusha G. , Baigmohammad Gouse , Mageswari Uma
Published: March 2024

The integration of Internet of Things (IoT) devices in Cyber- Physical Systems (CPS) continues to proliferate, ensuring the security of these interconnected systems becomes paramount. In existing research work focuses on the development and implementation of a cyber attack detection system for IoT-based CPS, leveraging Support Vector Machine (SVM) models. The SVM model, known for its effectiveness in binary classification tasks, is trained on historical data to distinguish between normal and malicious behavior patterns exhibited by IoT devices within the CPS. The SVM model is trained to learn the normal behavior of the system, enabling it to identify deviations indicative of cyber attacks. Realworld experiments and simulations demonstrate the efficacy of the SVMbased detection system in identifying various types of cyber threats. However, this research also acknowledges certain limitations. The SVM model's performance may be impacted by the dynamic and evolving nature of cyber threats, as it relies heavily on historical data for training and detection accuracy issues. To address the limitations of present cyber threat detection model , in this research work proposed a novel deep learning based CNN Model. The proposed model improve cyber attacks detection and performance metrics. The proposed model outperforms with the comparison of previous model. The performance measured in terms of accuracy, precision, recall and f1-score.
Predictive machine learning for optimal energy management in sustainable transportation systems
Authors: Ivanovich Vatin Nikolai , Manasa V.
Published: March 2024

This study explores the use of predictive machine learning techniques to enhance energy management in sustainable transportation systems, with a specific emphasis on electric vehicles (EVs). The analysis of EV specifications has shown a wide variety of battery capacities, ranging from 55 kWh to 75 kWh. These capacities have a direct impact on the energy storage capacity and the possible driving range of the vehicles. The range of vehicle weights, ranging from 1400 kg to 1700 kg, emphasized the possible effects on energy consumption rates and overall efficiency. The performance capabilities were shown with maximum speeds ranging from 160 km/h to 200 km/h. The energy consumption rates ranged from 0.18 kWh/km to 0.25 kWh/km, suggesting different levels of efficiency. An analysis of energy management data revealed that the lengths traveled varied from 180 km to 220 km, while the average speeds ranged from 50 km/h to 60 km/h. These variations directly affected the rates at which energy was used. The vehicles exhibited higher efficiency metrics by attaining energy consumption rates of 4.0 km/kWh to 5.6 km/kWh. The analysis of ambient variables indicated temperature fluctuations ranging from 20°C to 30°C, as well as a variety of terrain types that impact driving conditions and energy requirements. Predictive machine learning models demonstrated high accuracies, with Mean Absolute Error (MAE) values ranging from 0.13 to 0.18 kWh/km, Root Mean Squared Error (RMSE) values ranging from 0.18 to 0.22 kWh/km, and R-squared (R^2) scores ranging from 0.80 to 0.88. These results emphasize the need of using predictive machine learning to estimate energy consumption, optimize energy management systems, and address sustainable transportation concerns in order to improve the efficiency and sustainability of electric vehicles.
Blockchain-Enabled Cybersecurity Framework for Electric Transportation Systems
Authors: Ivanovich Vatin Nikolai , Ram Kumar R.P.
Published: March 2024

This article investigates the integration of blockchain technology into cybersecurity frameworks in electric transportation systems, evaluating the implications and advancements achieved in constructing a safe and resilient infrastructure. An analysis of electric vehicle (EV) specifications reveals a diverse range of battery capacity and driving ranges. As an example, the Tesla Model S has a battery capacity of 100 kWh, enabling it to go a distance of up to 320 miles. In contrast, the Nissan Leaf has a battery capacity of 40 kWh and a range of 150 miles. An examination of charging station data uncovers inconsistencies in power generation and transaction expenses. Charging stations with a higher power output of 100 kW have a price of up to $7, whilst stations with a lower power output of 50 kW charge $5. Moreover, the evaluation of cybersecurity metrics demonstrates significant improvements in data encryption and access control in high-security systems, demonstrating a 26% increase compared to low-security settings. An analysis of blockchain transaction records uncovers discrepancies in energy transfers between electric vehicles (EVs) and charging stations. It has been observed that some electric vehicles (EVs) transmit 50 kilowatt-hours (kWh) of energy, while others only transfer 25 kWh, leading to a notable 100% difference. These findings underscore the need of providing consumers with a diverse selection of electric vehicle options, the impact of location-based choices on charging infrastructure, the imperative of robust cybersecurity measures, and the many methods of energy transmission in electric transportation networks. This report offers comprehensive and crucial data that is necessary for stakeholders and policymakers seeking to enhance infrastructure and security systems to establish secure and efficient electric transportation ecosystems.
Fuzzy logic-based energy management in smart grids for renewable integration
Authors: Singh Harminder , Annapoorna E.
Published: March 2024

This study explores the creation and execution of energy management methods using fuzzy logic in smart grids, with the goal of effectively incorporating renewable energy sources. The research employs empirical data that includes information on renewable energy production, changes in energy use, the current state of battery storage, and control measures taken. The data analysis demonstrates significant variations in renewable energy sources, namely solar energy ranging from 350 kW to 410 kW, wind energy changing from 180 kW to 220 kW, and hydro energy varied from 120 kW to 150 kW. The energy consumption in different sectors exhibits varied patterns. Residential consumption ranges from 250 kW to 275 kW, industrial demand increases from 300 kW to 330 kW, and commercial consumption fluctuates from 200 kW to 225 kW. The battery storage status shows changes, with Battery 1 seeing an increase from 150 kWh to 165 kWh, Battery 2 fluctuating between 180 kWh and 195 kWh, and Battery 3 maintaining a stable range of 200 kWh to 215 kWh. The use of control actions based on fuzzy logic demonstrates flexibility, where Control Action 1 ranges from 0.6 to 0.8, Control Action 2 fluctuates from 0.5 to 0.7, and Control Action 3 varies from 0.6 to 0.9. The study highlights the flexibility and quick response of the energy management system based on fuzzy logic. It can adjust control actions in real-time to accommodate changes in renewable energy generation, consumption patterns, and battery storage. This indicates its potential to optimize energy flow and ensure grid stability in smart grids, facilitating the efficient integration of renewable energy.
Gliding Analysis of Segmented Flapping Wing
Authors: Govardhan D. , Kameswara Surya Teja K. , Jayahari L.
Published: March 2024

A variety of aircraft morphing technologies have been investigated and represented by various researchers in the public domain. The morphing wing concepts involved the modification of aircraft wings during the in-flight course. Most of the technologies/concepts were based on biomimicry, where wing aerodynamic performance improved due to the change in wing shape. Here we describe a novel concept where in the flow parameters of airfoils arranged in configurations are investigated. The flow parameters are investigated using the numerical simulation tool ANSYS. A 2d flow simulation is performed using a Fluent solver to evaluate the flow configuration of the airfoils arranged in different configurations. The first configuration of airfoils is named a base, wherein the airfoils are arranged at zero angles of attack. The other two configurations are arranged by increasing the angular position of airfoils i.e., 15, 30, and 45 degrees. All these configurations are aerodynamically investigated at different sub-sonic speeds.
Privacy-preserving location authentication for low-altitude UAVs: A blockchain-based approach
Authors: Pan Hengchang , Wang Yuanshuo , Wang Wei , Cao Ping , Ye Fangwei , Wu Qihui
Published: March 2024

Efficient and trusted regulation of unmanned aerial vehicles (UAVs) is an essential but challenging issue in the future era of the Internet of Low-altitude Intelligence, due to the difficulties in UAVs’ identity recognition and location matching, potential for falsified information reporting, etc. To address this challenging issue, in this paper, we propose a blockchain-based UAV location authentication scheme, which employs a distance bounding protocol to establish a location proof, ensuring the authenticity of UAV positions. To preserve the privacy of UAVs, anonymous certificates and zero-knowledge proof are used. The security of the proposed scheme is analyzed. Experiments demonstrate the efficiency and feasibility of the proposed scheme.
Driving STEM learning effectiveness: dropout prediction and intervention in MOOCs based on one novel behavioral data analysis approach
Authors: Xia Xiaona , Qi Wanxue
Published: March 2024

With the full application of MOOCs online learning, STEM multidisciplinary and knowledge structures have been achieved, but it has also resulted in a massive number of dropouts, seriously affected the learning sustainability of STEM education concepts, and made it difficult to achieve learning effectiveness. Based on the massive STEM learning behavior instances generated by MOOCs, as well as the entire learning periods, this study considers some key explicit and implicit features associated with learning behavior, and achieves the fusion of convolutional neural network and recurrent neural network through data-driven approaches, incorporates long short-term memory mechanism to develop dropout prediction methods and models. Based on the experimental results, we also discuss the relevant problems of dropouts related to STEM learning behavior, explore the key dropout temporal sequences of the learning process, identify related factors that have key impacts on learning behavior, and deduce intervention measures and early warning suggestions. The entire study can provide effective methods and decisions for researching the STEM learning behavior of MOOCs and has strong research feasibility and urgency.
Dictionaries and lexicography in the AI era
Authors: Lew Robert
Published: March 2024

This paper examines the implications of AI and machine translation on traditional lexicography, using three canonical scenarios for dictionary use: text reception, text production, and text translation as test cases. With the advent of high-capacity, AI-driven language models such as OpenAI’s GPT-3 and GPT-4, and the efficacy of machine translation, the utility of conventional dictionaries comes under question. Despite these advancements, the study finds that lexicography remains relevant, especially for less-documented languages where AI falls short, but human lexicographers excel in data-sparse environments. It argues for the importance of lexicography in promoting linguistic diversity and maintaining the integrity of lesser-known languages. Moreover, as AI technologies progress, they present opportunities for lexicographers to expand their methodology and embrace interdisciplinarity. The role of lexicographers is likely to shift towards guiding and refining increasingly automated tools, ensuring ethical linguistic data use, and counteracting AI biases.
Role of wave scattering in instability-induced Langmuir circulation
Authors: Vergeles Sergey S. , Vointsev Ivan A.
Published: March 2024

We consider a classical problem about dynamic instability that leads to the Langmuir circulation. The problem statement assumes that there is initially a wind-driven shear flow and a plane surface wave propagating in the direction of the flow. The unstable mode is a superposition of (i) shear flow and (ii) surface waves, both modulated in the horizontal spanwise direction and (iii) circulation that is made up with vortices forming near-surface rolls whose axes are coaligned along the shear flow streamlines and whose transverse size corresponds to the modulation period. Usually, the Langmuir circulation is understood as the vortical part of the mode slowly varying in time, which is the combination of the first and the last flows. The novelty of our approach is that we, first, take into account the scattering of the initial surface wave on the slow current. Second, we find the interference of the scattered and the initial waves generating a Stokes drift modulated in the same direction. Third, we establish the subsequent effect of the circulation by the vortex force created by the nonlinear interaction of the initial shear flow and the modulated part of the Stokes drift. Leibovich and Craik previously showed that the third part of the mechanism could maintain the Langmuir circulation. We calculate the growth rate that is approximately twice smaller than that obtained by Craik. The vertical structure of the circulation in the mode consists of two vortices, which corresponds to the next mode in Craik's model.
Deciphering the conformational preference and ionization dynamics of tetrahydrofuran: Insights from advanced spectroscopic techniques
Authors: Park Sung Man , Kwon Chan Ho
Published: March 2024

Tetrahydrofuran (THF) has garnered significant attention due to its pivotal role in biological and chemical processes. The diverse array of conformations exhibited by THF profoundly impacts its reactivity and interactions with other molecules. Understanding these conformational preferences is crucial for comprehending its molecular behavior. In this study, we utilize infrared (IR) resonant vacuum ultraviolet photoionization/mass-analyzed threshold ionization (VUV-PI/MATI) mass spectroscopies to capture distinctive vibrational spectra of individual conformers, namely, “twisted” and “bent,” within THF. Our conformer-specific vibrational spectra provide valuable insights into the relative populations of these two conformers. The analysis reveals that the twisted (C2) conformer is more stable than the bent (CS) conformer by 17 ± 15 cm−1. By precisely tuning the VUV photon energy to coincide with vibrational excitation via IR absorption, we selectively ionize specific conformers, yielding two-photon IR + VUV-PI/MATI spectra corresponding to the twisted and bent conformers. This investigation conclusively affirms that both the twisted and bent conformers coexist in the neutral state, while only the twisted conformer exists in the cationic state. These findings not only bridge gaps in existing knowledge but also provide profound insights into the behavior of this pivotal molecule in the realms of biology and medicine.
Effects of surface acoustic waves on reversal of magnetic domains in patterned films with perpendicular magnetic anisotropy
Authors: Li Xiaolei , Liu Qingfang , Qiao Huifang , Mi Shuai , Wu Huiliang , Gao Runliang , Ye Yuchen , Wang Jianbo
Published: March 2024

In this work, the magnetization reversal of patterned Pt/Co/Pt multilayers influenced by surface acoustic waves is investigated. For each patterned cell, the magnetization reversal involves formation of a reversal nucleus followed by rapid motion of a domain wall. The nucleation probability of the reversal nucleus increases with the power of the applied surface acoustic wave, which is explained by the magnetic droplet model, and fitting the experimental results with this model gives important parameters such as the domain-wall energy density and the reduction rate of local perpendicular anisotropy. The fitting results for different patterned cells are consistent with the experimental results, which validates this model for dealing with such issues.
Adaptive estimation of time-varying phase via weak value amplification
Authors: Shi Chunhui , Song Qi , Li Hongjing , Tan Xiaorui , Luo Zhongyuan , Huang Jingzheng , Zeng Guihua
Published: March 2024

The real-time estimation of a time-varying phase is of great importance in several fields. In order to estimate a time-varying phase with high precision and sensitivity, we propose and experimentally demonstrate an adaptive phase estimation method via weak value amplification by splitting the light into sensing path and monitoring path. In the proposed method, the phase shift can be amplified, an adjustable sensitivity and linear dynamic range can be obtained through the insertion of the reference phase, and a full-range phase estimation could be realized via an appropriate adjustment strategy. Furthermore, detectors with a higher resolution could be selected to detect weak signal by the adjustment of attenuation. Potentially, the phase estimation precision of about 10−8 rad could be achieved with the available equipment.
Non-monotonic variation of the thermoelectric efficiency with modulation mismatch in width-modulated nanowaveguides
Authors: Stefanou Antonios-Dimitrios , Chouthis Ioannis , Zianni Xanthippi
Published: March 2024

Efficient thermoelectric energy conversion at the nanoscale could power the Internet of Things and cool nanoelectronic circuits and improve the performance of quantum applications. Width-modulated nanowaveguides are suitable for these purposes because their thermoelectric efficiency can be geometrically tuned and integrated into the nanoelectronics industry processes. They are attracting increasing research interest stimulated by theoretical predictions for exceptional performance. To validate their potential, a better understanding of the effect of width modulation on thermoelectric efficiency is needed. So far, it is considered that (a) the thermoelectric efficiency increases monotonically with increasing width-mismatch due to decreasing phonon thermal conduction taking place without significantly affecting electron transport, (b) width-mismatch dominates the effect of width modulation in transport, and (c) phonons play the main role in increasing the thermoelectric efficiency. Here, we demonstrate counterevidence based on an investigation of the effect of width modulation on electrons so far overlooked. We reveal that (a) the thermoelectric efficiency varies non-monotonically with the modulation mismatch due to quantum effects on electron transport, (b) the modulation mismatch is quantified by the size-mismatch of the modulation rather than by the width-mismatch, and (c) it is electrons rather than phonons that play the main role in optimizing width modulation for maximum thermoelectric efficiency when quantum effects dominate. Our findings indicate that research should reorient from large width-mismatch toward optimal modulation-mismatch width-modulated nanostructures to enhance thermoelectric efficiency due to quantum effects. Our work provides new insight for designing nanowaveguides for efficient thermoelectric energy conversion at the nanoscale.
Optimization of the gamma reaction history diagnostic for double-shell pusher areal density and reaction history measurements on the National Ignition Facility
Authors: Dwyer R. H. , Meaney K. D. , Geppert-Kleinrath H. , Loomis E. N. , Robey H. F. , Mohamed Z. L. , Fry C. , Kim Y.
Published: March 2024

The double-shell inertial confinement fusion campaign, which consists of an aluminum ablator, a foam cushion, a high-Z pusher (tungsten or molybdenum), and liquid deuterium–tritium (DT) fuel, aims for its first DT filled implosions on the National Ignition Facility (NIF) in 2024. The high-Z, high density pusher does not allow x-rays to escape the double-shell capsule. Therefore, nuclear diagnostics such as the Gamma Reaction History (GRH) diagnostic on the NIF are crucial for understanding high-Z implosion performance. To optimize the GRH measurement of fusion reaction history and the pusher’s areal density, the MCNP6.3-based forward model of the detector was built. When calculating the neutron-induced inelastic gamma ray production, the interaction of neutrons with the compressed fuel was additionally included. By folding the calculated gamma ray spectrum output and the previously calibrated GRH detector responses, the optimum set of GRH energy thresholds for measuring the pusher areal density is determined to be 2.9 and 6.3 MeV for DT double-shell experiments. In addition, the effect of the down-scattering of neutrons on the gamma ray spectrum, the minimum required yield for measurements, and the attenuation of the gamma rays through the pusher are analyzed.
Investigation of Si incorporation in (010) β-Ga2O3 films grown by plasma-assisted MBE using diluted disilane as Si source and suboxide Ga2O precursor
Authors: Wen Zhuoqun , Zhai Xin , Lee Cindy , Kosanovic Stefan , Kim Yunjo , Neal Adam T. , Asel Thaddeus , Mou Shin , Ahmadi Elaheh
Published: March 2024

Traditionally, elemental Ga and Si have been used to supply Ga and Si, respectively, in molecular beam epitaxy (MBE) to grow Si-doped β-Ga2O3. In this work, we investigated the feasibility of enhancing the β-Ga2O3 growth rate by using a Ga-suboxide precursor in a plasma-assisted MBE. Additionally, Si doping of β-Ga2O3 using diluted disilane and Ga-suboxide as the Si and Ga precursors, respectively, was studied. The growth rate and film quality under different suboxide fluxes were inspected. We found that Si concentration has an inverse relationship with Ga2O flux due to atom competition. A room-temperature mobility of 115 cm2/V s was measured for an electron concentration of 1.2 × 1017 cm−3 on the sample grown using a Ga2O beam equivalent pressure of 1.1 × 10−7 Torr and a disilane flow rate of 0.006 sccm. Temperature-dependent Hall characterization was performed on this sample, revealing compensating acceptor and neutral impurity densities of 2.70 × 1015 and 8.23 × 1017 cm−3, respectively.
High-speed and wide-field 3D Raman imaging using flower-like gap-enhanced Raman tags
Authors: Chen Ming , Wang Jingfan , Li Da , Wang Bin , Wang Shuo , Zhao Xing , Meng Meng
Published: March 2024

Raman imaging technology plays a pivotal role in biomedical research, with the pursuit of higher resolution, faster imaging speed, and a larger field of view consistently driving the development of Raman imaging systems. In this work, we propose a high-speed and wide-field three-dimensional (3D) Raman imaging method based on light field microscopy and flower-like gap-enhanced Raman tags (F-GERTs). F-GERTs with enhanced Raman signals and high stability are used to label microbial and cell samples, avoiding the problem of photobleaching. The micro-lens array and scientific camera are incorporated to capture light field Raman images containing spatial information of the sample in a single snapshot acquisition process. The 3D reconstruction algorithm can complete the processing of the light field image within 1 min, reconstructing the 3D Raman image of the sample and the precisely slice structure at different depths. This high-speed and wide-field Raman imaging technology has great potential in the field of real-time 3D Raman imaging of microorganisms and cells.
Efficient strong-field THz generation from DSTMS crystal pumped by 1030 nm Yb-laser
Authors: Wang Kang , Zheng ZhuoRui , Li HongYang , Meng XianZe , Liu Yi , Tian Ye , Song Liwei
Published: March 2024

We report collinear strong-field terahertz (THz) generation from the organic crystal 4-N, N-dimethlamino-4-N-methyl-stilbazolium 2,4,6-trimethyl benzenesulfonate (DSTMS), driven by an industrial-grade ytterbium (Yb) laser operating at 1030 nm. The laser pulse duration is compressed from 800 to 90 fs by using a multi-pass-cell compressor. The output THz energy reaches 0.4 μJ, with a conversion efficiency of 0.22%. The spectrum covers over 0.1–6 THz with a peak electric field of 236 kV/cm. The phase matching condition and material absorption are illustrated. We demonstrate that a 1030 nm Yb-laser is used to pump organic crystal DSTMS for efficient THz generation in a simple collinear geometry, which provides a promising THz source based on an industrial-grade ultrafast laser.
Emergent high-temperature insulating ferromagnetism in Sr4Fe5CoO13-
δ
epitaxial thin films
Authors: Han Xu , Wang Jianlin , Gong Nanqi , Shan Zheling , Shi Wei , Liu Zhixin , Liu Xuguang , Cao Jiefeng , Peng Ranran , Huang Qiuping , Fu Zhengping , Lu Yalin
Published: March 2024

High-temperature ferromagnetic insulators play a crucial role in a wide range of emerging magnetoelectricity phenomena and hold the potential to become fundamental components of upcoming spintronic devices. However, the strong interaction between ferromagnetism and metallic properties presents a challenge, impeding the development of high-temperature ferromagnetic insulators based on oxides. Heterostructures or superlattice materials, especially those containing perovskite layers, offer a forward-looking solution. In this work, high-quality Sr4Fe6O13 (SFO) and cobalt-doped SFO (Sr4Fe5CoO13-δ, SFCO) thin films were grown on Nb-SrTiO3(001) substrates using pulsed laser deposition technology. The grown SFO films exhibit paramagnetism, possibly due to the transition of their film structure from the orthorhombic to the tetragonal phase. In contrast to SFO films, high-quality SFCO thin films exhibit significant ferromagnetism at room temperature, with Curie transition temperature as high as 800 K. This phenomenon is mainly attributed to the formed Dzyaloshinskii–Moriya interactions between Fe–O–Co and increased lattice distortions caused by Co-doping. In contrast, the Curie transition temperature of the SFCO film is slightly higher than that of the SFCO ceramics. This enhancement is likely due to surface effects, where an increase in surface energy introduces additional energy barriers at the film surface and interface, thereby enhancing the thermal stability of the film. These characteristics advance the research of high-temperature magnetic insulators and broaden the operating temperature range of spintronic devices based on ferromagnetic insulators.
Recipes for mixing vortices in a microchannel using electric field
Authors: Parashar Chintak Kamalesh , Singh Arshdeep , Ghosh Abir , Deshmukh Omkar Suresh , Bandyopadhyay Dipankar
Published: March 2024

Application of an electric field on the pressure-driven flow of a fluid inside a microchannel can create mixing vortices. The Coulombic force at electrode–fluid interface generates the additional stress to engender the instability. While the previous studies show the phenomena at the two-layer immiscible or miscible flows, we show the same for a single fluid system. Linear stability analysis (LSA), non-linear simulations, and experiments together uncover the conditions for onset and propagation of such instabilities with Reynolds (Re) and electric field Rayleigh (Raψ) numbers. The LSA uncover that a higher critical field (larger Racψ) is required to destabilize a flow with a higher flow rate (higher Re), highlighting the stabilizing nature of the inertia. Subsequently, the non-linear simulations and experiments uncover that such systems can develop localized steady or unsteady vortices with time in order to dissipate the excess localized electrical energy originating from the applied field. Example cases are shown wherein the size, number, and recirculation strength of the vortices have been tuned inside the microchannel with the variations in the external field intensity and the arrangements of the electrodes for a fixed Re. The study further unveils that while at lower Raψ only be steady vortices may show up for the fluids with higher viscosities, at the significantly higher Raψ the fluids with a lower viscosity may manifest an array of unsteady counter-rotating vortices. Such vortices may translate due to the flow of the fluid inside the confined microfluidic channel to eventually form a “vortex-street” inside the microchannel.
Investigating structural, optical, and electron-transport properties of lithium intercalated few-layer MoS2 films: Unraveling the influence of disorder
Authors: Hrdá J. , Moško M. , Píš I. , Vojteková T. , Pribusová Slušná L. , Hutár P. , Precner M. , Dobročka E. , Španková M. , Hulman M. , Chromik Š. , Siffalovic P. , Bondino F. , Sojková M.
Published: March 2024

Molybdenum disulfide is a promising candidate for various applications in electronics, optoelectronics, or alkali-ion batteries. The natural presence of the van der Waals gap allows intercalating alkali ions, such as lithium, into MoS2 films. Intercalation can modify the electronic structure as well as the electrical and optical properties. Here, we present a structural, optical, and electrical characterization of Li-intercalated few-layer MoS2 films. The intercalation was carried out by annealing MoS2 film in the presence of Li2S powder, serving as a lithium source. The initial MoS2 layers were prepared by pulsed laser deposition (PLD) and by sulfurization of 1 nm thick Mo film (TAC). The presence of lithium was confirmed by synchrotron-based x-ray Photoelectron Spectroscopy. The Raman spectroscopy, x-ray diffraction, and optical absorption measurements confirmed semiconducting behavior for all samples. All samples exhibited the thermally activated dependence of the electrical resistance, R, typical for the Efros–Shklovskii variable range hopping in a disordered semiconductor, ln R(T) ∝ (TES/T)1/2, where kBTES is the hopping activation energy. The PLD-grown MoS2 samples exhibited a relatively mild initial disorder primarily caused by grain boundaries. Lithium intercalation led to an increase in disorder, evident in the increase in kBTES and a substantial rise in electrical resistance. The TAC-grown undoped MoS2 sample already exhibited significant resistance, and the impact of Li intercalation on resistance was minimal. This observation was attributed to the fact that the TAC-grown MoS2 samples exhibit a perturbed stoichiometry (the S:Mo ratio ∼ 2.20), causing strong disorder even before Li intercalation. The electron doping caused by lithium, if any, was completely obscured by the effect of disorder.
Planar-type SiGe thermoelectric generator with double cavity structure
Authors: Koike S. , Yanagisawa R. , Jalabert L. , Anufriev R. , Kurosawa M. , Mori T. , Nomura M.
Published: March 2024

Thermoelectric power generation is a promising technology that can directly convert thermal energy into electrical energy and is expected to be applied as power supplies for low-power electronic devices, such as sensors. In particular, planar-type devices fabricated based on lithography processes not only enable significant device miniaturization and lower cost but also take advantage of materials with smaller dimensions, such as thin films and nanowires, which have attracted much attention in recent years. Silicon germanium (SiGe) is a promising thermoelectric material due to its relatively high power factor, low thermal conductivity, and compatibility with standard top-down fabrication process. We design and fabricate a planar-type thermoelectric generator with a double cavity structure using a 240 nm thick Si0.8Ge0.2 thin film and report its performance improvement. When the temperature difference is applied to the device, the measured power density of 100 μWcm−2 was achieved at ΔT = 15 K, namely, the performance normalized by the applied temperature was 0.43 μWcm−2K−2. Finally, the dependence of the device performance on the SiGe film thickness is discussed. The results from our simulation show that a maximum performance of 1.75 μWcm−2K−2 can be achieved by the current device structure, indicating the potential for future applications as thermoelectric energy harvesters.
Low-temperature stable ferroelectric–antiferroelectric transition for cryogenic energy storage application
Authors: Han Bing , Xia Jiake , Fu Zhengqian , Hu Tengfei , Li Zhenqin , Cao Fei , Yan Shiguang , Chen Xuefeng , Wang Genshui , Xu Fangfang
Published: March 2024

The capacitors are in rising demand for cryogenic applications. As for now, it still remains an ongoing challenge for simultaneously achieving high energy storage density and cryogenic temperature stability. Herein, the strategy of stable backward phase transition was demonstrated in the antiferroelectric composition of (Pb0.9175La0.055)(Zr0.975Ti0.025)O3. As a result, we achieved high recoverable energy density about 10 J/cm3 with exceptional low-temperature stability from −160 to 25 °C. Multi-layer ceramic capacitors designed for pulse discharge applications also demonstrated high performance in cryogenic conditions, with the peak current fluctuations of less than 4%. Through in situ characterizations using x-ray diffraction, Raman spectra, and transmission electron microscopy, we discovered that the anisotropic structural evolution is responsible for a stable backward phase transition, providing the material with robust stability at cryogenic temperatures. These results offer a good paradigm for improving the temperature stability of antiferroelectric multi-layer capacitors to meet the rigorous demands of energy storage applications.
Cost-optimal seeding strategy during a botanical pandemic in domesticated fields
Authors: Lazebnik Teddy
Published: March 2024

Botanical pandemics cause enormous economic damage and food shortages around the globe. However, since botanical pandemics are here to stay in the short-medium term, domesticated field owners can strategically seed their fields to optimize each session’s economic profit. In this work, we propose a novel epidemiological-economic mathematical model that describes the economic profit from a field of plants during a botanical pandemic. We describe the epidemiological dynamics using a spatiotemporal extended susceptible-infected-recovered epidemiological model with a non-linear output economic model. We provide an algorithm to obtain an optimal grid-formed seeding strategy to maximize economic profit, given field and pathogen properties. We show that the recovery and basic infection rates have a similar economic influence. Unintuitively, we show that a larger farm does not promise higher economic profit. Our results demonstrate a significant benefit of using the proposed seeding strategy and shed more light on the dynamics of the botanical pandemic.
Electrolyte optimization for sodium-sulfur batteries
Authors: Basel Janak , Sapkota Nawraj , Parekh Mihir , Rao Apparao M.
Published: March 2024

Due to high theoretical capacity, low cost, and high energy density, sodium-sulfur (Na-S) batteries are attractive for next-generation grid-level storage systems. However, the polysulfide shuttle leads to a rapid capacity loss in sodium-sulfur batteries with elemental sulfur as the cathode material. Most previous studies have focused on nanoengineering methods for creating stable Na anodes and S cathodes. A proven strategy to mitigate the shuttle effect is to covalently bond elemental sulfur to a polymeric backbone and use it as the active ingredient instead of elemental sulfur. In this regard, we synthesized sulfurized polyacrylonitrile (SPAN) cathodes. In addition to the electrodes, electrolyte selection is crucial for sodium sulfur batteries with long cycle life, high energy densities, and rate capabilities. Thus, we explored various electrolyte compositions; specifically organic solvents such as propylene carbonate (PC), dioxolane (DOL), dimethoxyethane, and diglyme (DIG) were mixed in different proportions to create electrolyte solvents with both ethers and carbonates to promote the formation of bilateral solid electrolyte interphase (SEI). This bilateral SEI strategy has been employed to prevent polysulfide shuttle and dendrite growth in lithium-sulfur batteries. Sodium bis(trifluoromethanesulfonyl)imide (NaTFSI) was chosen as the electrolyte salt. The prepared coin cells were tested for rate capability and capacity retention, and the results have been analyzed. High initial discharge capacity of ∼740 mAh g−1 with ∼66% capacity retention over 100 cycles was observed for 0.8M NaTFSI in PC50DOL50 (v/v). The cell with 0.8M NaTFSI in PC50DIG50 has exhibited strong capacity retention of 74.60% with excellent Coulombic efficiency of 99%. Molecular dynamics (MD) simulations were carried out to further understand these results.
Colossal barocaloric effect of the spin-crossover compound {Fe(pz)2(BH3CN)2} near room temperature
Authors: Li Ruixin , Zhang Zhe , Bibik Yurii S. , Gural'skiy Il'ya A. , Zatovsky Igor. V. , Liu Zhaodong , Li Quanjun , Li Bing , Levchenko Georgiy , Liu Bingbing
Published: March 2024

As one of the most likely alternatives to traditional vapor compression refrigeration technology, solid refrigeration technology based on the barocaloric effect (BCE) has attracted extensive attention in recent years. Spin-crossover (SCO) compounds are considered suitable for working at low driving pressures due to high-pressure sensitivity and small hysteresis width. However, the entropy change (ΔSSCO) of the SCO compound is smaller than that of other excellent barocaloric materials (plastic crystals and two-dimensional perovskites). Here, we report the BCE of the SCO compound {Fe(pz)2(BH3CN)2} (pz = pyrazine) with a smaller molar mass and a third source of entropy change besides electron and vibrational entropy changes. Compound {Fe(pz)2(BH3CN)2} exhibits high pressure sensitivity (dT1/2dP= 20.2 K kbar−1) as well as entropy change (ΔSSCO= 202 J kg−1 K−1). The maximum values of reversible isothermal entropy change (ΔSit,rev,max) and adiabatic temperature change (ΔTad,rev,max) at 1 kbar are only 103 J kg−1 K−1 and ∼0 K, respectively, due to the hysteresis behavior. However, at sufficiently high driving pressures, ΔSit,rev,max exceeds 200 J kg−1 K−1, and ΔTad,rev,max can reach ∼47 K, which exceeds all SCO compounds reported in BCE studies and is comparable to some plastic-crystalline and two-dimensional perovskite barocaloric materials. The excellent BCE of the SCO compound {Fe(pz)2(BH3CN)2} is mainly due to its small molar mass, which makes the unit mass compound exhibit higher ΔSSCO, while the introduction of the third source of entropy change—the reorientation entropy change (ΔSreo), only plays a small role. This is expected to promote the practical application of SCO compounds as barocaloric refrigerants.
Negative bias stress stable PtOx/InGaZnOx Schottky barrier diodes optimized by oxygen annealing
Authors: Li Haoxin , Han Zhao , Zhou Xuanze , Xu Guangwei , Long Shibing
Published: March 2024

In this work, bottom-Schottky-structure InGaZnOx (IGZO) Schottky barrier diodes (SBDs) with sputtered PtOx anodes were fabricated and annealed in oxygen at different temperatures. Critical parameters and negative bias stress (NBS) stability of SBDs with different annealing temperatures are investigated. With the annealing temperature increases, the barrier height and rectification ratio of the SBDs exhibited a rising-then-declining trend, while the ideality factor slightly increased until 200 °C. The SBDs show up overall reliability except for a leakage current rising trend under light, which can be attributed to free electron generation from the ionized oxygen vacancy. Among all the SBDs, the 175 °C annealed ones exhibited the best overall performance, including a high barrier height of 0.89 eV, an ideality factor of 1.14, and a large rectification ratio of over 108. Compared to the initial SBDs, the annealed ones showed up great improvement in NBS stability except for the 200 °C annealed ones, which was permanently degraded and not able to recover to original states. According to experimental result analysis and IGZO material characteristics, a stability model based on the subgap trap transition from VO2+ to VO and new VO2+ creation was proposed, which applies to both the short-term and long-term NBS tests. The results above demonstrate that oxygen annealing at appropriate temperature is an effective method to improve both device performance and NBS stability for PtOx–IGZO SBDs.
In situ separation of plasma-generated species using metal–organic frameworks
Authors: Takagi Kyotaro , Kanno Moriyuki , Muneoka Hitoshi , Terashima Kazuo , Ito Tsuyohito
Published: March 2024

Selectively extracting the desired reactive species from plasma could unlock various applications for plasma. This study uncovers the potential of metal–organic frameworks (MOFs) in selectively extracting plasma-generated species from the plasma environment. To demonstrate this, we utilized a zeolitic imidazolate frameworks-8 (ZIF-8) as the MOF separation membrane and Ar/C3H8 plasma. The ZIF-8 membrane proved effective in selectively extracting H2 molecules produced from C3H8, as compared with the case without the ZIF-8.
Activity trends of Pd clusters supported on C2N for oxygen evolution and reduction reactions
Authors: Huang Longkun , Li Min , Wang Hui , Zhang Long
Published: March 2024

Developing highly efficient electrocatalysts for the oxygen evolution reaction (OER) and reduction reaction (ORR) is crucial for future renewable energy technology. Here, we use first-principles calculations combined with genetic algorithm to determine the structures of various Pd clusters supported on experimentally available C2N monolayer and evaluate the OER and ORR performance. Our findings show that the activity of the supported Pd clusters is closely linked to the local geometrical and electronic structure of the active site. Furthermore, we establish the activity trends of the clusters based on the adsorption free energies of intermediates. In particular, C2N supported Pd7 and Pd8 clusters exhibit outstanding OER activity with low overpotentials. We identify a volcano relation for the OER on the clusters, suggesting that the high activity of the cluster is related to the moderate adsorption strength of intermediates. Mechanistic analysis indicates that the second water formation is the potential-determining step for ORR on the clusters due to the strong adsorption of *OH. Additionally, we identify a linear scaling relationship between the ORR overpotentials and adsorption free energies of *OH, demonstrating that reducing the adsorption strength of reaction intermediates on Pd clusters can improve the activity. This work unravels the activity trends of cluster catalysts and provides strategies for the rational design of highly efficient single-cluster catalysts for OER and ORR.
Extracting double-quantum coherence in two-dimensional electronic spectroscopy under pump–probe geometry
Authors: Cai Mao-Rui , Zhang Xue , Cheng Zi-Qian , Yan Teng-Fei , Dong Hui
Published: March 2024

Two-dimensional electronic spectroscopy (2DES) can be implemented with different geometries, e.g., BOXCARS, collinear, and pump–probe geometries. The pump–probe geometry has the advantage of overlapping only two beams and reducing phase cycling steps. However, its applications are typically limited to observing the dynamics with single-quantum coherence and population, leaving the challenge to measure the dynamics of the double-quantum (2Q) coherence, which reflects the many-body interactions. We demonstrate an experimental technique in 2DES under pump–probe geometry with a designed pulse sequence and the signal processing method to extract 2Q coherence. In the designed pulse sequence, with the probe pulse arriving earlier than the pump pulses, our measured signal includes the 2Q signal as well as the zero-quantum signal. With phase cycling and data processing using causality enforcement, we extract the 2Q signal. The proposal is demonstrated with rubidium atoms. We observe the collective resonances of two-body dipole–dipole interactions in both the D1 and D2 lines.
Effects of Ni2+ doping on magnetic and magnetoelectric properties of Y-type hexaferrite BaSrCo2Fe11AlO22
Authors: Wang Qingkai , Yu Zhipeng , Zhai Kun , Wang Bochong , Mu Congpu , Wen Fusheng , Xiang Jianyong , Xue Tianyu , Nie Anmin , Liu Zhongyuan
Published: March 2024

Magnetoelectric hexaferrites are the promising candidate materials for low-consumption magnetic memory device application, due to the existence of room-temperature magnetoelectric effect and the tunable magnetic structure. In this work, we studied the Ni doping effect on a rare room-temperature multiferroic BaSrCo2Fe11AlO22. With the comprehensive study of magnetism, magnetoelectricity, and ferroelectric properties, magnetoelectric phase diagrams of BaSrCo2-xNixFe11AlO22 were established. Generally, Ni doping has two important effects on magnetic and magnetoelectric properties. One is to strengthen superexchange interactions, greatly enhancing magnetic order temperature. Another effect is to destabilize the noncollinear magnetic structure at high temperature, causing the absence of ME effect at room temperature. In addition, the converse ME effects have been studied, revealing that converse ME coupling strength become weakened with the increase in Ni concentration. Our systematic studies provide important clues for synthesizing high performance magnetoelectric hexaferrites.
Average turbulence dynamics from a one-parameter kinetic theory: Estimation of the relaxation time
Authors: Chen Hudong , Staroselsky Ilya , Sreenivasan Katepalli R. , Yakhot Victor
Published: March 2024

We provide a theoretical estimation of the relaxation time for the kinetic theoretical representation of homogeneous, isotropic, and stationary turbulent flow. The basic approach depends on the construction of a balance of fluctuation and dissipation between the relaxation process and the self-consistently generated fluctuating force. The kinetic theory representation generalizes the modeling of turbulence so that turbulent viscosity as well as all higher order transport coefficients are determined by the relaxation time. The resulting value of the relaxation time gives an estimation of the turbulent viscosity with the coefficient value comparable with those from most of the representative turbulence models, which have been obtained empirically or semi-empirically.
Coarse-grained modeling of DNA–RNA hybrids
Authors: Ratajczyk Eryk J. , Šulc Petr , Turberfield Andrew J. , Doye Jonathan P. K. , Louis Ard A.
Published: March 2024

We introduce oxNA, a new model for the simulation of DNA–RNA hybrids that is based on two previously developed coarse-grained models—oxDNA and oxRNA. The model naturally reproduces the physical properties of hybrid duplexes, including their structure, persistence length, and force-extension characteristics. By parameterizing the DNA–RNA hydrogen bonding interaction, we fit the model’s thermodynamic properties to experimental data using both average-sequence and sequence-dependent parameters. To demonstrate the model’s applicability, we provide three examples of its use—calculating the free energy profiles of hybrid strand displacement reactions, studying the resolution of a short R-loop, and simulating RNA-scaffolded wireframe origami.