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21 pages, 12189 KiB  
Article
Experimental Investigation and Modelling of the Incipient Fault of Low-Voltage XLPE Cables in Wet Environments
by Chen Zeng, Yunhe Wang, Miaomiao Wu, Yanru Lei, Jing Yong and Xiaojing Wang
Appl. Sci. 2025, 15(8), 4524; https://doi.org/10.3390/app15084524 - 19 Apr 2025
Viewed by 374
Abstract
The study of incipient faults due to insulation defects in cables is crucial for preventing electrical fires and ensuring personal safety. However, research on incipient faults in low-voltage cables remains relatively underexplored compared to that on medium-voltage cables. This paper focuses on low-voltage [...] Read more.
The study of incipient faults due to insulation defects in cables is crucial for preventing electrical fires and ensuring personal safety. However, research on incipient faults in low-voltage cables remains relatively underexplored compared to that on medium-voltage cables. This paper focuses on low-voltage cross-linked polyethylene (XLPE) cables and investigates the changes in voltage and current caused by insulation defects in different wet conditions. The main findings are that the voltage applied to the cable with defective insulation shows sub-cycle disturbances that become more frequent. The current in the cable conductor shows a pulsed shape, coincident with the voltage disturbances. Over time, the sub-cycle disturbances gradually disappear, instead, the steady-state leakage current emerges. The wet conditions affect waveforms of the voltage/current disturbance and the frequency of occurrence. The findings provide detailed and unique characteristics of the voltage and current during the cable incipient fault, which are different from those of the incipient fault in the medium-voltage cables. The simulation and analysis support the experimental results. Based on the experimental results, a model is developed for further research on LV-cable incipient fault detection and protection. Full article
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15 pages, 14778 KiB  
Article
Localized Vector Optical Nondiffracting Subcycle Pulses
by Klemensas Laurinavičius and Sergej Orlov
Appl. Sci. 2024, 14(24), 11538; https://doi.org/10.3390/app142411538 - 11 Dec 2024
Cited by 1 | Viewed by 995
Abstract
Structured light is essential in various fields such as imaging, communications, computing, laser microprocessing, and ultrafast and nonlinear optics. The structuring of light can occur in terms of space, amplitude, phase, polarization, time, frequency, and duration. One of the intriguing properties that can [...] Read more.
Structured light is essential in various fields such as imaging, communications, computing, laser microprocessing, and ultrafast and nonlinear optics. The structuring of light can occur in terms of space, amplitude, phase, polarization, time, frequency, and duration. One of the intriguing properties that can be obtained is resistance to the diffractive spread and dispersive broadening of the pulsed beams. This happens when temporal properties such as frequency are coupled with spatial properties like angles of propagation of plane-wave components. In this case, pulsed light beams exhibit characteristics similar to optical bullets, resisting both diffraction and material dispersion. This study questions whether free-space optical bullets that possess nondiffracting and nondispersive properties are possible with subcycle durations. We report on the possibility to create nondiffracting and nondispersing localized subcycle pulsed beams and their complex polarization topologies when controlling the group velocity of these light structures. Full article
(This article belongs to the Special Issue Ultrafast and Nonlinear Laser Applications)
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31 pages, 10502 KiB  
Article
Flexible Simulation Platform for Generating Realistic Waveforms with Voltage Notches
by Joaquín E. Caicedo, Olga Zyabkina, Edwin Rivas and Jan Meyer
Appl. Sci. 2024, 14(23), 11031; https://doi.org/10.3390/app142311031 - 27 Nov 2024
Viewed by 864
Abstract
Voltage notches are steady-state sub-cycle waveform distortions caused by the normal operation of line-commutated power converters, significantly impacting power quality in industrial low-voltage (LV) networks. Despite their common occurrence, research on this phenomenon is still incipient, and realistic simulation platforms are lacking. This [...] Read more.
Voltage notches are steady-state sub-cycle waveform distortions caused by the normal operation of line-commutated power converters, significantly impacting power quality in industrial low-voltage (LV) networks. Despite their common occurrence, research on this phenomenon is still incipient, and realistic simulation platforms are lacking. This paper introduces a detailed MATLAB (R2024a)/Simulink-based simulation platform that models a benchmark low-voltage industrial installation, including a six-pulse controlled rectifier, linear loads, and a capacitor bank for power factor correction. Systematic simulations are performed with the platform to examine the sensitivity of notch characteristics to key parameters within plausible ranges, such as short-circuit power at the point of common coupling, commutation reactance, firing angle, snubber circuits, and rated power of the rectifier. In addition, parameters such as the rated power of linear loads and the compensation power of the capacitor bank are examined. Other influencing parameters including background voltage unbalance and distortion are also modeled and considered. A comparative analysis with field measurements from German industrial LV networks validates the plausibility and suitability of the simulations. Building upon this platform, a Monte Carlo simulation approach is adopted to generate extensive datasets of realistic voltage notch waveforms by randomly varying these key parameters. A case study conducted under conditions typical of German LV networks demonstrates the applicability of the simulations. To support further research, the simulation platform and exemplary synthetic waveforms are provided alongside the paper, serving as a valuable tool for testing and designing strategies for analysis, detection, and monitoring of voltage notches. Full article
(This article belongs to the Special Issue Analysis, Modelling and Simulation in Electrical Power Systems)
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12 pages, 809 KiB  
Article
I3oT (Industrializable Industrial Internet of Things) Tool for Continuous Improvement in Production Line Efficiency by Means of Sub-Bottleneck Detection Method
by Javier Llopis, Antonio Lacasa, Nicolás Montés and Eduardo Garcia
Machines 2024, 12(11), 760; https://doi.org/10.3390/machines12110760 - 29 Oct 2024
Cited by 1 | Viewed by 1011
Abstract
The present paper shows how to develop an I3oT (Industrializable Industrial Internet of Things) tool for continuous improvement in production line efficiency by means of the sub-bottleneck detection method. There is a large amount of scientific literature related to the detection of bottlenecks [...] Read more.
The present paper shows how to develop an I3oT (Industrializable Industrial Internet of Things) tool for continuous improvement in production line efficiency by means of the sub-bottleneck detection method. There is a large amount of scientific literature related to the detection of bottlenecks in production lines. However, there is no scientific literature that develops tools to improve production lines based on the bottlenecks that go beyond rebalancing tasks. This article explores the concept of a sub-bottleneck. In order to detect sub-bottlenecks in a massive way, the use of one of the I3oT (Industrializable Industrial Internet of Things) tools developed in our previous work, the mini-terms, is proposed. These mini-terms use the existing sensors for the normal operation of the production lines to measure the sub-cycle times and use them to predict the deterioration of the machine components found in the production lines. The sub-bottleneck algorithms proposed are used in two real twin lines at the Ford manufacturing plant in Almussafes (Valencia), the (3LH) and (3RH), to show how the lines can be continuously improved by means of sub-bottleneck detection. Full article
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30 pages, 33212 KiB  
Article
A Study on Adaptive Implicit–Explicit and Explicit–Explicit Time Integration Procedures for Wave Propagation Analyses
by Delfim Soares, Isabelle de Souza Sales, Lucas Ruffo Pinto and Webe João Mansur
Acoustics 2024, 6(3), 651-680; https://doi.org/10.3390/acoustics6030036 - 23 Jul 2024
Cited by 1 | Viewed by 1581
Abstract
This study delves into the effectiveness of two time integration techniques, namely the adaptive implicit–explicit (imp–exp) and explicit–explicit (exp–exp) methods, which stand as efficient formulations for tackling intricate systems characterized by multiple time scales. The imp–exp technique combines implicit and explicit procedures by [...] Read more.
This study delves into the effectiveness of two time integration techniques, namely the adaptive implicit–explicit (imp–exp) and explicit–explicit (exp–exp) methods, which stand as efficient formulations for tackling intricate systems characterized by multiple time scales. The imp–exp technique combines implicit and explicit procedures by employing implicit formulations for faster components and explicit calculations for slower ones, achieving high accuracy and computational efficiency. Conversely, the exp–exp method, a variation of explicit methods with sub-cycling, excels in handling locally stiff systems by employing smaller sub-steps to resolve rapid changes while maintaining stability. For both these approaches, numerical damping may be activated by adaptive time integration parameters, allowing numerical dissipation to be locally applied, if necessary, as a function of the considered discrete model and its computed responses, enabling a highly effective numerical dissipative algorithm. Furthermore, both these techniques stand as very simple and straightforward formulations as they rely solely on single-step displacement–velocity relations, describing truly self-starting procedures, and they stand as entirely automated methodologies, requiring no effort nor expertise from the user. This work provides comparative studies of the adaptive imp–exp and exp–exp approaches to assess their accuracy and efficiency across a wide range of scenarios, with emphasis on geophysical applications characterized by multiscale problems, aiming to establish under which circumstances one approach should be preferred over the other. Full article
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11 pages, 2895 KiB  
Article
Substitution Effect of a Single Nitrogen Atom on π-Electronic Systems of Linear Polycyclic Aromatic Hydrocarbons (PAHs): Theoretically Visualized Coexistence of Mono- and Polycyclic π-Electron Delocalization
by Jong Min Lim, Sangdeok Shim, Hoa Thi Bui, Jimin Kim, Ho-Joong Kim, Yoon Hwa and Sung Cho
Molecules 2024, 29(4), 784; https://doi.org/10.3390/molecules29040784 - 8 Feb 2024
Cited by 5 | Viewed by 2111
Abstract
We theoretically investigated the nitrogen substitution effect on the molecular structure and π-electron delocalization in linear nitrogen-substituted polycyclic aromatic hydrocarbons (N-PAHs). Based on the optimized molecular structures and magnetic field-induced parameters of fused bi- and tricyclic linear N-PAHs, we found that the local [...] Read more.
We theoretically investigated the nitrogen substitution effect on the molecular structure and π-electron delocalization in linear nitrogen-substituted polycyclic aromatic hydrocarbons (N-PAHs). Based on the optimized molecular structures and magnetic field-induced parameters of fused bi- and tricyclic linear N-PAHs, we found that the local π-electron delocalization of subcycles (e.g., mono- and bicyclic constituent moieties) in linear N-PAHs is preserved, despite deviation from ideal structures of parent monocycles. The introduction of a fused five-membered ring with a pyrrolic N atom (N-5MR) in linear N-PAHs significantly perturbs the π-electronic condition of the neighboring fused six-membered ring (6MR). Monocyclic pyrrole exhibits substantial bond length alternations, strongly influencing the π-electronic systems of both the fused N-5MR and 6MR in linear N-PAHs, depending on the location of shared covalent bonds. A fused six-membered ring with a graphitic N atom in an indolizine moiety cannot generate monocyclic π-electron delocalization but instead contributes to the formation of polycyclic π-electron delocalization. This is evidenced by bifurcated diatropic ring currents induced by an external magnetic field. In conclusion, the satisfaction of Hückel’s 4n + 2 rule for both mono- and polycycles is crucial for understanding the overall π-electron delocalization. It is crucial to consider the unique characteristics of the three types of substituted N atoms and the spatial arrangement of 5MR and 6MR in N-PAHs. Full article
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12 pages, 1850 KiB  
Communication
RFID Adaptive Parallel Response Collision Tree Algorithm Based on Lock-Bit
by Xuan Luo, Xiaolin Jia and Yajun Gu
Sensors 2024, 24(2), 389; https://doi.org/10.3390/s24020389 - 9 Jan 2024
Cited by 2 | Viewed by 1358
Abstract
This paper proposes the Lock-Position-Based RFID Adaptive Parallel Collision Tree (LAPCT) algorithm to address the issues of excessive time slots required in the identification process of collision tree algorithms for multiple tags and the high communication complexity between the reader and multiple tags. [...] Read more.
This paper proposes the Lock-Position-Based RFID Adaptive Parallel Collision Tree (LAPCT) algorithm to address the issues of excessive time slots required in the identification process of collision tree algorithms for multiple tags and the high communication complexity between the reader and multiple tags. The LAPCT algorithm adopts a single-query multiple-response mechanism and dynamically divides the response sub-cycle numbers in the identification cycle based on an adaptive strategy. It uses Manchester encoding to lock collision positions and generate a common query prefix, effectively reducing the number of reader queries. This reduction in queries decreases the total number of required time slots and transmitted bits during the reader–tag communication process, thereby improving the efficiency of multiple tag recognition. Theoretical and simulation experiments demonstrate that compared to similar algorithms, the LAPCT algorithm achieves a maximum reduction of 37% in total time slots required, a maximum improvement of 30% in recognition efficiency, and a maximum reduction of 90% in communication complexity. Furthermore, with an increase in the number of tags, the performance advantages of the LAPCT algorithm become more pronounced, making it suitable for large-scale tag scenarios. Full article
(This article belongs to the Section Physical Sensors)
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32 pages, 10843 KiB  
Article
Performance Analysis and Multi-Objective Optimization of a Cooling-Power-Desalination Combined Cycle for Shipboard Diesel Exhaust Heat Recovery
by Qizhi Gao, Senyao Zhao, Zhixiang Zhang, Ji Zhang, Yuan Zhao, Yongchao Sun, Dezhi Li and Han Yuan
Sustainability 2023, 15(24), 16942; https://doi.org/10.3390/su152416942 - 18 Dec 2023
Cited by 5 | Viewed by 1635
Abstract
This study presents a novel cooling-power-desalination combined cycle for recovering shipboard diesel exhaust heat, integrating a freezing desalination sub-cycle to regulate the ship’s cooling-load fluctuations. The combined cycle employs ammonia–water as the working fluid and efficiently utilizes excess cooling capacity to pretreat reverse [...] Read more.
This study presents a novel cooling-power-desalination combined cycle for recovering shipboard diesel exhaust heat, integrating a freezing desalination sub-cycle to regulate the ship’s cooling-load fluctuations. The combined cycle employs ammonia–water as the working fluid and efficiently utilizes excess cooling capacity to pretreat reverse osmosis desalination. By adjusting the mass flow rate of the working fluid in both the air conditioning refrigeration cycle and the freezing desalination sub-cycle, the combined cycle can dynamically meet the cooling-load demand under different working conditions and navigation areas. To analyze the cycle’s performance, a mathematical model is established for energy and exergy analysis, and key parameters including net output work, comprehensive efficiency, and heat exchanger area are optimized using the MOPSO algorithm. The results indicate that the system achieves optimal performance when the generator temperature reaches 249.95 °C, the sea water temperature is 22.29 °C, and 42% ammonia–water is used as the working fluid. Additionally, an economic analysis of frozen seawater desalination as RO seawater desalination pretreatment reveals a substantial cost reduction of 22.69%, showcasing the advantageous features of this proposed cycle. The research in this paper is helpful for waste energy recovery and sustainable development. Full article
(This article belongs to the Section Sustainable Engineering and Science)
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15 pages, 10707 KiB  
Article
Polar Ocean Tides—Revisited Using Cryosat-2
by Ole Baltazar Andersen, Stine Kildegaard Rose and Michael G. Hart-Davis
Remote Sens. 2023, 15(18), 4479; https://doi.org/10.3390/rs15184479 - 12 Sep 2023
Cited by 6 | Viewed by 2246
Abstract
With the availability of more than 9 years of Cryosat-2, it is possible to revisit polar ocean tides, which have traditionally been difficult to determine from satellite altimetry. The SAMOSA+ physical retracker is a stable retracker developed particularly for Cryosat-2. Being a physical [...] Read more.
With the availability of more than 9 years of Cryosat-2, it is possible to revisit polar ocean tides, which have traditionally been difficult to determine from satellite altimetry. The SAMOSA+ physical retracker is a stable retracker developed particularly for Cryosat-2. Being a physical retracker, it enables the determination of the sea state bias. Correcting for the sea state bias enables more reliable sea level estimates compared with traditional empirical retrackers used before. Cryosat-2 data have been analyzed for residual ocean tides to the FES2014 ocean tide model in the Arctic Ocean and Antarctic Ocean using the response formalism. We utilize data from the sub-cycle of Cryosat-2, which follows a repeating pattern of approximately 28.33 days. This sub-repeat period makes it an advantageous alias period for the majority of significant constituents. This allowed for the estimation and mapping of the major tidal constituents in the open ocean and also in floating ice shelves from data extracted from leads in the sea ice. A novel empirical ocean tide model designed specifically for the polar region, DTU22, is introduced. Our findings reveal substantial enhancements in semi-diurnal tides within the Arctic Ocean and improvement in diurnal constituents within the Southern Ocean. In the Southern Ocean, the diurnal constituents are particularly improved using the empirical model by more than a factor of two to around 3 cm for both constituents compared with FES2014b. These outcomes underscore the significance of incorporating the reprocessed and retracted Cryosat-2 data into tidal modeling, highlighting its pivotal role in advancing the field. Full article
(This article belongs to the Special Issue Advances in Satellite Altimetry)
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18 pages, 7668 KiB  
Article
A Study of Drought and Flood Cycles in Xinyang, China, Using the Wavelet Transform and M-K Test
by Xinchen Gu, Pei Zhang, Wenjia Zhang, Yang Liu, Pan Jiang, Shijie Wang, Xiaoying Lai and Aihua Long
Atmosphere 2023, 14(8), 1196; https://doi.org/10.3390/atmos14081196 - 25 Jul 2023
Cited by 12 | Viewed by 2186
Abstract
Accurately identifying and predicting droughts can provide local managers with a basis for decision-making. The Xinyang region is prone to droughts and floods, which have a large impact on local agriculture and socio-economics. This paper employs precipitation data from the Xinyang region to [...] Read more.
Accurately identifying and predicting droughts can provide local managers with a basis for decision-making. The Xinyang region is prone to droughts and floods, which have a large impact on local agriculture and socio-economics. This paper employs precipitation data from the Xinyang region to provide a scientific basis for drought and flood control measures in this region. The data are first treated with standardized precipitation indices (SPIs) on three-month, six-month, and nine-month time scales. Subsequently, a Morlet wavelet analysis is performed for each of the three time scales analyzed for the SPI. The results show multiple time scales of drought and flood disasters in the Xinyang region. The cycles of drought and flood disasters in the Xinyang region show different fluctuations on different SPI scales. The SPI time series reflect a strong fluctuation period of 17a for drought and flood disasters in the Xinyang region. An analysis of the variance of the wavelet coefficients showed that the first main cycle of drought and flood disasters in the Xinyang region is 7a, and the second and third sub-cycles are 4a and 13a, respectively. We conclude that floods are more frequent than droughts in Xinyang and are more likely to occur from 2017 to 2021, with a subsequent shift to droughts. Local managers should put drought prevention measures in place to deal with droughts after 2021. Full article
(This article belongs to the Special Issue Extreme Events and Risk of Disasters)
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15 pages, 2156 KiB  
Review
Genetic Control of Avian Migration: Insights from Studies in Latitudinal Passerine Migrants
by Aakansha Sharma, Sayantan Sur, Vatsala Tripathi and Vinod Kumar
Genes 2023, 14(6), 1191; https://doi.org/10.3390/genes14061191 - 29 May 2023
Cited by 5 | Viewed by 3437
Abstract
Twice-a-year, large-scale movement of billions of birds across latitudinal gradients is one of the most fascinating behavioral phenomena seen among animals. These seasonal voyages in autumn southwards and in spring northwards occur within a discrete time window and, as part of an overall [...] Read more.
Twice-a-year, large-scale movement of billions of birds across latitudinal gradients is one of the most fascinating behavioral phenomena seen among animals. These seasonal voyages in autumn southwards and in spring northwards occur within a discrete time window and, as part of an overall annual itinerary, involve close interaction of the endogenous rhythm at several levels with prevailing photoperiod and temperature. The overall success of seasonal migrations thus depends on their close coupling with the other annual sub-cycles, namely those of the breeding, post-breeding recovery, molt and non-migratory periods. There are striking alterations in the daily behavior and physiology with the onset and end of the migratory period, as shown by the phase inversions in behavioral (a diurnal passerine bird becomes nocturnal and flies at night) and neural activities. Interestingly, there are also differences in the behavior, physiology and regulatory strategies between autumn and spring (vernal) migrations. Concurrent molecular changes occur in regulatory (brain) and metabolic (liver, flight muscle) tissues, as shown in the expression of genes particularly associated with 24 h timekeeping, fat accumulation and the overall metabolism. Here, we present insights into the genetic basis of migratory behavior based on studies using both candidate and global gene expression approaches in passerine migrants, with special reference to Palearctic-Indian migratory blackheaded and redheaded buntings. Full article
(This article belongs to the Section Animal Genetics and Genomics)
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11 pages, 2874 KiB  
Communication
Valley-Selective Polarization in Twisted Bilayer Graphene Controlled by a Counter-Rotating Bicircular Laser Field
by Jiayin Chen, Candong Liu and Ruxin Li
Photonics 2023, 10(5), 516; https://doi.org/10.3390/photonics10050516 - 1 May 2023
Cited by 8 | Viewed by 2794
Abstract
The electron valley pseudospin in two-dimensional hexagonal materials is a crucial degree of freedom for achieving their potential application in valleytronic devices. Here, bringing valleytronics to layered van der Waals materials, we theoretically investigate lightwave-controlled valley-selective excitation in twisted bilayer graphene (tBLG) with [...] Read more.
The electron valley pseudospin in two-dimensional hexagonal materials is a crucial degree of freedom for achieving their potential application in valleytronic devices. Here, bringing valleytronics to layered van der Waals materials, we theoretically investigate lightwave-controlled valley-selective excitation in twisted bilayer graphene (tBLG) with a large twist angle. It is demonstrated that the counter-rotating bicircular light field, consisting of a fundamental circularly-polarized pulse and its counter-rotating second harmonic, can manipulate the sub-cycle valley transport dynamics by controlling the relative phase between two colors. In comparison with monolayer graphene, the unique interlayer coupling of tBLG renders its valley selectivity highly sensitive to duration, leading to a noticeable valley asymmetry that is excited by single-cycle pulses. We also describe the distinct signatures of the valley pseudospin change in terms of observing the valley-selective circularly-polarized high-harmonic generation. The results show that the valley pseudospin dynamics can still leave visible fingerprints in the modulation of harmonic signals with a two-color relative phase. This work could assist experimental researchers in selecting the appropriate protocols and parameters to obtain ideal control and characterization of valley polarization in tBLG. Full article
(This article belongs to the Special Issue Light Control and Particle Manipulation)
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12 pages, 5576 KiB  
Article
High-Intensity Harmonic Generation with Energy Tunability Produced by Robust Two-Color Linearly Polarized Laser Fields
by Wendi Lan, Xinyu Wang, Yue Qiao, Shushan Zhou, Jigen Chen, Jun Wang, Fuming Guo and Yujun Yang
Symmetry 2023, 15(3), 580; https://doi.org/10.3390/sym15030580 - 23 Feb 2023
Cited by 3 | Viewed by 2240
Abstract
By using the numerical solution of the time-dependent Schrödinger equation, we theoretically explored the high-order harmonic generation process under the interaction of high-intensity two-color ultrashort driving laser pulses with atoms. The symmetry of the electric field of the laser pulse will be broken. [...] Read more.
By using the numerical solution of the time-dependent Schrödinger equation, we theoretically explored the high-order harmonic generation process under the interaction of high-intensity two-color ultrashort driving laser pulses with atoms. The symmetry of the electric field of the laser pulse will be broken. The producing electric field was controlled at the subcycle level by an IR laser and its second harmonic, which has the unique characteristic that two sequential half-cycles become distinct, rather than merely opposite in sign. Compared with the case of the atom in the fundamental laser pulse, the harmonic efficiency showed an increase of 1∼2 orders of magnitude at specific harmonic order with this combined pulse action. Through the theoretical analysis with the “three-step model”, it was demonstrated that the enhancement of the harmonic intensity is due to the fast ionization of electrons at the ionization moment and the short time from ionization to recombination of ionized electrons. In addition, effects of the peak field amplitude ratio, the full width at half maximum, the phase delay of the two-color pulses, the laser intensity and ionization probability on the harmonic efficiency enhancement were also investigated. Full article
(This article belongs to the Section Physics)
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18 pages, 2733 KiB  
Article
Advances in the Implementation of the Exactly Energy Conserving Semi-Implicit (ECsim) Particle-in-Cell Method
by Giovanni Lapenta
Physics 2023, 5(1), 72-89; https://doi.org/10.3390/physics5010007 - 18 Jan 2023
Cited by 12 | Viewed by 3051
Abstract
The energy-conserving semi-implicit (ECsim) method presented by the author in 2017, is a particle-in-cell (PIC) algorithm for the simulation of plasmas. Energy conservation is achieved within a semi-implicit formulation that does not require any non-linear solver. A mass matrix is introduced to linearly [...] Read more.
The energy-conserving semi-implicit (ECsim) method presented by the author in 2017, is a particle-in-cell (PIC) algorithm for the simulation of plasmas. Energy conservation is achieved within a semi-implicit formulation that does not require any non-linear solver. A mass matrix is introduced to linearly express the particle-field coupling. With the mass matrix, the algorithm preserves energy conservation to machine precision. The construction of the mass matrix is the central nature of the method and also the main cost of the computational cycle. Here, three methods that modify the construction of the mass matrix are analyzed. First, the paper considers how the sub-cycling of the particle motion modifies the mass matrix. Second, a form of smoothing that reduces the noise while retaining exact energy conservation is introduced. Finally, an approximation of the mass matrix is discussed that transforms the ECsim scheme to the implicit moment method. Full article
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9 pages, 2857 KiB  
Article
A Novel p-Type ZnCoxOy Thin Film Grown by Atomic Layer Deposition
by Leyi Li, Zhixin Wan, Quan Wen, Zesheng Lv and Bin Xi
Nanomaterials 2022, 12(19), 3381; https://doi.org/10.3390/nano12193381 - 27 Sep 2022
Cited by 1 | Viewed by 1618
Abstract
Reported herein is the atomic layer deposition (ALD) of novel ternary ZnCoxOy films possessing p-type semiconducting behavior. The preparation comprises of optimized ZnO and Co3O4 deposition in sub-cycles using the commercially available precursors cyclopentadienylcobalt dicarbonyl (CpCo(CO)2 [...] Read more.
Reported herein is the atomic layer deposition (ALD) of novel ternary ZnCoxOy films possessing p-type semiconducting behavior. The preparation comprises of optimized ZnO and Co3O4 deposition in sub-cycles using the commercially available precursors cyclopentadienylcobalt dicarbonyl (CpCo(CO)2), diethylzinc (DEZ) and ozone (O3). A systematic exploration of the film’s microstructure, crystallinity, optical properties and electrical properties was conducted and revealed an association with Zn/Co stoichiometry. The noteworthy results include the following: (1) by adjusting the sub-cycle of ZnO/ Co3O4 to 1/10, a spinel structured ZnCoxOy film was grown at 150 °C, with it exhibiting a smooth surface, good crystallinity and high purity; (2) the material transmittance and bandgap decreased as the Co element concentration increased; (3) the ZnCoxOy film is more stable than its p-type analog Co3O4 film; and (4) upon p-n diode fabrication, the ZnCoxOy film demonstrated good rectification behaviors as well as very low and stable reverse leakage in forward and reverse-biased voltages, respectively. Its application in thin film transistors and flexible or transparent semiconductor devices is highly suggested. Full article
(This article belongs to the Section Nanocomposite Materials)
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