bluuebunny/crossref_metadata_2025 huggingface dataset:
Les crises épileptiformes chez les petits mammifères
Authors: Boussarie Didier
Published: July 2024

Les crises épileptiformes ou convulsives sont peu fréquentes chez le lapin et les rongeurs de compagnie. Leur origine peut être très diverse chez le lapin, qu’elle soit environnementale, émotionnelle, toxique, métabolique, cardiovasculaire, traumatique, algique ou agonique.

Certaines crises sont spécifiques d’espèce chez les rongeurs : prurit épileptogène du cobaye, épilepsie par carence en vitamine B1 chez le chinchilla, épilepsie essentielle de la gerbille.

Chez le furet, on trouve les causes de convulsions communes aux autres carnivores, mais surtout les crises hypoglycémiques en relation avec un insulinome.

Dans tous les cas, il est important de réaliser une prise en charge immédiate pour faire cesser rapidement les crises sous peine de lésions cérébrales irréversibles.
Nicht medikamentöse Prophylaxe und Therapie der Demenz durch Bewegung und Sport
Authors: Maschke Matthias
Published: July 2024

Vor dem Hintergrund der Zunahme demenzieller Erkrankungen sind nicht medikamentöse Therapiemaßnahmen zur Verminderung der Neuerkrankungsrate an Demenz und zur Behandlung demenzerkrankter Patienten überaus wichtig. Bewegung und Sport zählen zu den am besten bewiesenen Maßnahmen. Freiwillige physische Aktivität führt tierexperimentell zu einer Verminderung von ß-Amyloid-Plaques und Erhöhung von neurotrophen Faktoren wie BDNF. Multimodale Interventionsstudien zeigten in größeren Studien einen Effekt auf die Kognition gesunder älterer Menschen oder bei Patienten mit gering ausgeprägter Demenz. Welche genauen Bewegungsübungen jedoch am wirksamsten sind, muss in Studien noch geklärt werden.
Implementing interdisciplinary sustainability education with the food-energy-water (FEW) nexus
Authors: Romulo Chelsie , Venkataraman Bhawani , Caplow Susan , Ajgaonkar Shamili , Allen Craig R. , Anandhi Aavudai , Anderson Steven W. , Azzarello Caterina Belle , Brundiers Katja , Blavascunas Eunice , Dauer Jenny M. , Druckenbrod Daniel L. , Fairchild Ennea , Horne Lydia R. , Lee Kyungsun , Mwale Marizvkuru , Mischler John , Pappo Emily , Patel Nirav S. , Sintov Nicole D. , Ramsdell Carla S. , Vincent Shirley G.
Published: July 2024

Growth in the green jobs sector has increased demand for college graduates who are prepared to enter the workforce with interdisciplinary sustainability skills. Simultaneously, scholarly calls for interdisciplinary collaboration in the service of addressing the societal challenges of enhancing resilience and sustainability have also increased in recent years. However, developing, executing, and assessing interdisciplinary content and skills at the post-secondary level has been challenging. The objective of this paper is to offer the Food-Energy-Water (FEW) Nexus as a powerful way to achieve sustainability competencies and matriculate graduates who will be equipped to facilitate the transformation of the global society by meeting the targets set by the United Nations Sustainable Development Goals. The paper presents 10 curricular design examples that span multiple levels, including modules, courses, and programs. These modules enable clear evaluation and assessment of key sustainability competencies, helping to prepare graduates with well-defined skillsets who are equipped to address current and future workforce needs.
Optical contrast analysis of α-RuCl3 nanoflakes on oxidized silicon wafers
Authors: Ivanova Tatyana V. , Andres-Penares Daniel , Wang Yiping , Yan Jiaqiang , Forbes Daniel , Ozdemir Servet , Burch Kenneth S. , Gerardot Brian D. , Brotons-Gisbert Mauro
Published: July 2024

α-RuCl3, a narrow-band Mott insulator with a large work function, offers intriguing potential as a quantum material or as a charge acceptor for electrical contacts in van der Waals devices. In this work, we perform a systematic study of the optical reflection contrast of α-RuCl3 nanoflakes on oxidized silicon wafers and estimate the accuracy of this imaging technique to assess the crystal thickness. Via spectroscopic micro-ellipsometry measurements, we characterize the wavelength-dependent complex refractive index of α-RuCl3 nanoflakes of varying thickness in the visible and near-infrared. Building on these results, we simulate the optical contrast of α-RuCl3 nanoflakes with thicknesses below 100 nm on SiO2/Si substrates under different illumination conditions. We compare the simulated optical contrast with experimental values extracted from optical microscopy images and obtain good agreement. Finally, we show that optical contrast imaging allows us to retrieve the thickness of the RuCl3 nanoflakes exfoliated on an oxidized silicon substrate with a mean deviation of −0.2 nm for thicknesses below 100 nm with a standard deviation of only 1 nm. Our results demonstrate that optical contrast can be used as a non-invasive, fast, and reliable technique to estimate the α-RuCl3 thickness.
An improved artificial spin ice structure for restoring ice degeneracy
Authors: Xie Yunlong , Li Ping , Zheng Shuhan , Liu Meifeng , Liu Jun-Ming
Published: July 2024

It is known that rare-earth-based pyrochlore oxide may accommodate the well-defined two-in-two-out spin ice state with its tetrahedral unit. Low-energy excitation is argued to favor the highly concerned monopole state which attracts essential attention. However, such an excitation cannot be directly tracked and imaged using advanced characterizations, raising challenges to our understanding of the physics of monopoles. In this work, we propose an improved two-dimensional artificial spin ice structure on the Shastry–Sutherland lattice to restore the degeneracy of realistic pyrochlore systems. Such a structure avoids the deficiency of inequivalent nearest and next-nearest exchanges in the planar quadrate unit, which, however, is equivalent to the tetrahedral unit of realistic pyrochlore oxides. Therefore, this spin ice model restores state degeneracy that is lost in conventional planar artificial spin ice structures, representing an improved simulator of real spin ice systems. Our careful investigations of such improved structures reveal the rich physics of spin ice excitations, including the phase diagram, which allows different ordered phases and interesting critical phase transitions between spin ice phase I and phase II. Energy spectrum analysis suggests that restoration of state degeneracy substantially reduces monopole excitation energy, resulting in a striking monopole emergency at the critical point. Furthermore, the emergent spin dimer phase in this improved model allows high-density monopole excitations and exhibits high-correlated monopole fluid states.
Unique stick–slip crack dynamics of double-network hydrogels under pure-shear loading
Authors: Zheng Yong , Wang Yiru , Tian Fucheng , Nakajima Tasuku , Hui Chung-Yuen , Gong Jian Ping
Published: July 2024

In this work, we have found that a prenotched double-network (DN) hydrogel, when subjected to tensile loading in a pure-shear geometry, exhibits intriguing stick–slip crack dynamics. These dynamics synchronize with the oscillation of the damage (yielding) zone at the crack tip. Through manipulation of the loading rate and the predamage level of the brittle network in DN gels, we have clarified that this phenomenon stems from the significant amount of energy dissipation required to form the damage zone at the crack tip, as well as a kinetic contrast between the rapid crack extension through the yielding zone (slip process) and the slow formation of a new yielding zone controlled by the external loading rate (stick process).
Resolving the overlooked photochemical nitrophenol transformation mechanism induced by nonradical species under visible light
Authors: Liu Shujun , Wang Hong , Hu Zehui , Zhang Xin , Sun Yanjuan , Dong Fan
Published: July 2024

Nitrophenols present on the surface of particulates are ubiquitous in the atmosphere. However, its atmospheric photochemical transformation pathway remains unknown, for which the crucial effect of visible light is largely overlooked, resulting in an incomplete understanding of the effects of nitrophenols in the atmospheric environment. This study delves into the photolysis mechanism of 4-nitrophenol (4NP), one of the most abundant atmospheric nitrophenol compounds, on the surface of photoactive particulates under visible light irradiation. Unexpectedly, the nonradical species (singlet oxygen,
1
O
2
) was identified as a dominant factor in driving the visible photolysis of 4NP. The pathways of HONO and p-benzoquinone (C
6
H
4
O
2
) generation were clarified by acquiring direct evidence of C–N and O–H bond breakage in the nitro (–NO
2
) and hydroxyl (–OH) groups of 4NP. The further decomposition of HONO results in the generation of NO and hydroxyl radicals, which could directly contribute to atmospheric oxidizing capacity and complicate the PM
2.5
composition. Significantly, the behavior of
1
O
2
-induced visible photolysis of 4NP was universal on the surface of common particulates in the atmosphere, such as A1 dust and Fe
2
O
3
. This work advances the understanding of the photochemical transformation mechanism of particulate-phase atmospheric nitrophenols, which is indispensable in elucidating the role of nitrophenols in atmospheric chemistry.
Klein tunneling and Fabry-Perot resonances in the α - T
3 bilayer with aligned stacking
Authors: Benhaida O , Drissi L B , Saidi E H , Ahl Laamara R
Published: July 2024

This paper investigates the quantum tunneling effect on the α − T
3 bilayer with aligned stacking. An effective model is constructed to describe the properties around the triple band crossings for stacking with a vertical alignment of sites in the bilayer system. Focusing on these band crossings, it is found that while the energy spectrum remains gapless throughout, it is characterized by flat energy bands. Subsequently, the transmission coefficient, T, for Dirac quasi-electrons across a rectangular potential barrier is calculated, alongside the relationship between the transmission rate and the coupling parameter α. It is observed that super-tunnel phenomena occur at certain values of the quasiparticle energy, where the transmission is perfect regardless of the angle of incidence on the barrier, with α = 1. Furthermore, it is found that for a wide range of parameter values, the transmittance evolves monotonically and exponentially with increasing alpha. The paper also highlights the occurrence of the Klein paradox in the system, where quasiparticles approaching the barrier with zero-angle incidence exhibit ideal quantum transparency.
Complex scaling method applied to the study of the Swanson Hamiltonian in the broken PT-symmetry phase
Authors: Fernández Viviano , Ramírez Romina , Reboiro Marta
Published: July 2024

In this work, we study the non-PT symmetry phase of the Swanson Hamiltonian in the framework of the Complex Scaling Method. By constructing a bi-orthogonality relation, we apply the formalism of the response function to analyse the time evolution of different initial wave packages. The Wigner Functions, mean value of operators, and the probabilities of survival and persistence for the different wave packages are evaluated as a function of time. We analyse in detail the time evolution in the neighbourhood of Exceptional Points. We derive a continuity equation for the system. We compare the results obtained using the Complex Scaling Method to the ones obtained by working in a Rigged Hilbert Space.
Experimental and computational investigation of FGM coated cylinder liners prepared using HVOF technique
Authors: Ranjan Prabhat , Kumar Rajesh , Walia R S , Yadav Vinod Kumar
Published: July 2024

In the present work, to improve the wear resistance of the cylinder liner, without affecting the heat dissipation, cast steel cylinder liners are coated with five-layer Functionally Graded Material (FGM) coatings prepared using High-velocity oxy-fuel (HVOF) technique. The powders were designated as C1 (WC-10Co-4Cr) which is Tungsten Carbide with 10% Cobalt and 4% Chromium, C2 (WC-12Co) which is Tungsten Carbide with 12% Cobalt and C3 (Ni-25Cr) which is Nickel with 25% Chromium. The results revealed that the FGM coating designated as Functionally Graded Coated Sample-1 (FGCS-1) wears less compared to Functionally Graded Coated Sample-2 (FGCS-2) and Functionally Graded Coated Sample-3 (FGCS-3), due to the presence of wear resistive elements in the composition and uniform material homogeneity. Numerical analysis of FGCS-2, conducted using Ansys Fluent software, revealed a negligible temperature gradient across the coating thickness. This is due to the highly conductive coating material and the extremely thin coating layers, making it suitable for engine cylinder liner applications where less wear and high heat transfer rate is desirable.
Design of hollow-core anti-resonant optical fiber based on bragg elements with low-loss and wide bandwidth
Authors: Ding Li-Sha , Chen Ming-Yang , Ding Jin-Long
Published: July 2024

A type of anti-resonant hollow-core optical fiber consisting of Bragg elements is proposed. The confinement and bending losses are numerically simulated using the finite element method. It is found that the introduction of concentric rings to form anti-resonant structure can reduce the mode transmission loss by 2 ∼ 4 orders of magnitude compared with the anti-resonant element composed of only one dielectric layer, therefore it can achieve ultra-low loss optical transmission. The influence of the structural parameters on the confinement loss was investigated. Furthermore, it is demonstrated that each dielectric layer independently contributes to the confinement of the core modes. It is also found that the Bragg reflection structure can effectively suppress the coupling between core and cladding modes, and achieve broadband low-loss optical transmission under small bending radius. In particular, it can achieve a low transmission loss of less than 0.1 dB km−1 over a wide wavelength range of 600 nm at the bending radius of 3 cm.
Primordial magnetic fields: consistent initial conditions and impact on high-z structures
Authors: Ralegankar Pranjal , Pavičević Mak , Viel Matteo
Published: July 2024

Primordial magnetic fields (PMFs) can enhance matter power spectrum on small scales (≲ Mpc) and still agree with bounds from cosmic microwave background (CMB) and Faraday rotation measurements. As modes on scales smaller than Mpc have already become non-linear today, exploring PMFs' impact on small-scale structures requires dedicated cosmological simulations. Here, for the first time, we perform a suite of hydrodynamical simulations that take into account the different impacts of PMFs on baryons and dark matter. Specifically, in the initial conditions we displace particles according to the Lorentz force from PMFs. We also highlight the large theoretical uncertainty in the peak enhancement of the matter power spectrum due to PMFs, which was not considered in previous studies. We present halo mass functions and show that they can be accurately reproduced using Sheth-Tormen formalism. Moreover, we show that PMFs can generate galaxies with baryon fraction several times larger than the cosmic average at high redshifts. This is simply a consequence of the fact that PMFs enhance baryon perturbations, causing them to be larger than dark matter perturbations. We argue that this scenario could be tested soon by obtaining accurate estimates of the baryon fraction in high redshift galaxies.
Evolution of light deflection and shadow from a gauge-potential-like AdS black hole under the influence of a non-magnetic plasma medium
Authors: Ali Riasat , Tiecheng Xia , Awais Muhammad , Babar Rimsha
Published: July 2024

We investigate the light deflection in the weak field approximation from the accelerating charged AdS black hole. For this purpose, we apply the Gauss–Bonnet theorem to calculate the light deflection in the weak field area and use the Gibbons–Werner approach to analyze the optical geometry of the accelerating charged AdS black hole in the non-magnetic plasma absence/presence of a non-magnetic medium. We also represent the graphical behavior of the light deflection angle w.r.t. the impact parameter. We also compute the light deflection angle using Keeton and Petters approximations under the impact of accelerating charged AdS black hole geometry. Furthermore, by using the ray-tracing approach, we determine the shadow in the non-magnetic plasma presence and also demonstrate that graphical shadow has an impact on the gauge potential, non-magnetic plasma frequencies and charge.
Holographic thermodynamics of a charged AdS black hole with a global monopole
Authors: Zheng Hebin , Chen Yunxian , Tang Jian
Published: July 2024

By regarding the Newton constant G

N
and cosmological constant Λ as variables, in this paper we study the thermodynamics and phase transition of the Reissner-Nordstr

o

̈

m

anti-de Sitter (RN-AdS) black hole with a global monopole within the framework of AdS/CFT correspondence. We find interesting critical phenomena and phase behavior in the (grand) canonical ensembles of fixed (

Q

˜

,
V
,
C

), (

Φ

˜

,
V
,
C

) and (

Q

˜

,
V
,
μ

). When the other parameters are fixed, the free energy decreases with the global monopole increases. In the (

Q

˜

,
V
,
C

) ensemble, the range of the unstable region decreases with the increase of the global monopole. In the (

Φ

˜

,
V
,
C

) ensemble, when

Φ

˜

<

Φ

c

, the free energy appears as two branches, where the upper and lower branches correspond to low and high entropy, respectively. When (

Q

˜

,
V
,
μ

) is fixed, a new zero-order phase transition occurs in the high-entropy phase and the low-entropy phase at certain μ-dependent temperatures. When μ increases to a certain value, this zero-order phase transition disappears. This certain value is negatively related to the magnitude of the global monopole. Finally, we find that

p
−
V

criticality does not appear with the change of global monopole. Therefore, it is important to note that the CFT states of charged black holes with global monopoles do not correspond to van der Waals fluids. Finally, we find that charged black holes with global monopoles can better reflect thermodynamic phase transitions and critical phenomena under the AdS/CFT correspondence. By adjusting the change of the global monopole, the thermodynamic phase transition will also change.
The B-site ordering in RFe0.5Cr0.5O3 ceramics and its effect on magnetic properties
Authors: Hou 侯 Li 利 , Shi 石 Lei 磊 , Yang 杨 Liping 利平 , Liu 刘 Yiqiang 义强 , Li 李 Zhitao 志涛 , Meng 孟 Lanxiang 蓝翔
Published: July 2024

To insight into the B-site ordering in RFe0.5Cr0.5O3 ceramics, a series of RFe0.5Cr0.5O3 ceramics (R = La, Y, Lu) were synthesized by the sol–gel method, and the structural and magnetic properties were systemically investigated. By using the Rietveld refinement of all samples, it is found that the structural distortion is increased as the R ionic radius decreases, leading to the weakened interactions between Fe/Cr ions. Moreover, the Fe and Cr are arranged in disorder in LaFe0.5Cr0.5O3, but partially ordered in YFe0.5Cr0.5O3 and LuFe0.5Cr0.5O3, showing an increasing trend of the proportion of ordered domains with the decrease of R ionic radius. Through fitting the temperature-dependent magnetizations, it is identified that the magnetization reversal (MR) in disorder LaFe0.5Cr0.5O3 is resulted from the competition between the moments of Cr and Fe sublattices. In the partially ordered YFe0.5Cr0.5O3 and LuFe0.5Cr0.5O3 ceramics, because of the presence of Fe–O–Cr networks in the ordered domains whose moment is antiparallel to that of Fe–O–Fe and Cr–O–Cr in the disordered domains, the compensation temperature T
comp of MR is increased by nearly 50 K. These results suggest that the changing of R-site ions could be used very effectively to modify the Fe–O–Cr ordering, apart from the structural distortion, which has a direct effect on the magnetic exchange interactions in RFe0.5Cr0.5O3 ceramics. Then at values of composition where ordered domains are expected to be larger in number as compared to disordered domains and with a weaker structural distortion, one can expect a higher transition temperature T
comp, providing a different view for adjustment of the magnetic properties of RFe0.5Cr0.5O3 ceramics for practical applications.
Polarity-controllable magnetic skyrmion filter
Authors: Ai 艾 Xiao-Lin 啸林 , Li 李 Hui-Ting 慧婷 , Zhang 张 Xue-Feng 雪枫 , Li 李 Chang-Feng 昌锋 , Shim 沈 Je-Ho 帝虎 , Ma 马 Xiao-Ping 晓萍 , Piao 朴 Hong-Guang 红光
Published: July 2024

The skyrmion generator is one of the indispensable components for the future functional skyrmion devices, but the process of generating skyrmion cannot avoid mixing with other magnetic textures, such as skyrmionium and nested skyrmion bags. These mixed magnetic textures will inevitably lead to the blockage of skyrmion transport and even the distortion of data information. Therefore, the design of an efficient skyrmion filter is of great significance for the development of skyrmion-based spintronic devices. In this work, a skyrmion filter scheme is proposed, and the high-efficiency filtering function is demonstrated by micromagnetic simulations. The results show that the filtering effect of the scheme depends on the structure geometry and the spin current density that drives the skyrmion. Based on this scheme, the polarity of the filtered skyrmion can be controlled by switching the magnetization state at the output end, and the “cloning” of the skyrmion can be realized by geometric optimization of the structure. We believe that in the near future, the skyrmion filter will become one of the important components of skyrmion-based spintronic devices in the future.
Geometric properties of the first singlet S-wave excited state of two-electron atoms near the critical nuclear charge
Authors: Chen 陈 Tong 彤 , Yang 杨 Sanjiang 三江 , Zhou 周 Wanping 挽平 , Mei 梅 Xuesong 雪松 , Qiao 乔 Haoxue 豪学
Published: July 2024

The geometric structure parameters and radial density distribution of 1s2s 1S excited state of the two-electron atomic system near the critical nuclear charge Z
c were calculated in detail under tripled Hylleraas basis set. Contrary to the localized behavior observed in the ground and the doubly excited 2p2
3Pe states, for this state our results identify that while the behavior of the inner electron increasingly resembles that of a hydrogen-like atomic system, the outer electron in the excited state exhibits diffused hydrogen-like character and becomes perpendicular to the inner electron as nuclear charge Z approaches Z
c. This study provides insights into the electronic structure and stability of the two-electron system in the vicinity of the critical nuclear charge.
Based on the Security Control of Pumped Storage Hydropower under Extreme Fault Conditions after Grid Connection
Authors: Xiao Qin , Bai Zhidan , Zhang Anan
Published: July 2024

As an important part of the new energy grid connection, pumped storage hydropower plays an important role in black start, frequency modulation and phase modulation, peak shaving and valley filling, energy storage and accident reserve. In order to ensure the security and stability of the power system under extreme fault conditions after the pumped storage hydropower is connected to the grid, it is particularly important to configure reasonable security and stability control measures. Based on the development status and operation characteristics of pumped storage hydropower stations at home and abroad, considering the need of system security and stability control, this paper takes a pumped storage hydropower station in Southwest China as an example to simulate and analyze the transient characteristics of the pumped storage hydropower after grid connection. In view of the possible extreme fault conditions, a regional security control system is designed, and the configuration, control measures and strategies of the security control device on the pumping side are studied.
Short-term Load Forecasting and Regime Switching Detection Based on Normalized Causal Entropy Boosting
Authors: Gao Haiyang , Ma Bin , Xu Qiongjing , Wang Yuting , Zhu Haichao
Published: July 2024

This paper introduces a method based on normalized causal entropy boosting (NCEBoosting) to identify regime switches in load patterns and improve the adaptability of prediction models. Load time-series exhibit multidimensional, nonlinear changes influenced by factors such as human behavior and meteorological environments. To detect regime switches, we calculate the sparsified causal entropy matrix using a small batch of load flow data, which corrects the original prediction model. Subsequently, the corrected model is employed to predict the load requirements after the switch. By comparing the causal entropy across different time periods, we effectively detect conceptual drift, phase changes, and unexpected events in the data, enabling the determination of load mode switches. Given that load timing data is typically generated in batches, calculating the causal entropy of successive data batches provides a robust metric. In this paper, we determine the load mode change by calculating the integrated causal entropy of the batch data streams and calibrating the prediction model accordingly. Extensive computational experiments on real building load datasets are conducted to validate the proposed method. The results demonstrate that the normalized causal entropy boosting effectively detects load mode switches compared to traditional approaches. Furthermore, the method demonstrates efficient adaptive learning based on online data streams, resulting in improved adaptability and prediction accuracy.
Intelligent Diagnosis Method of Transformer Based on Oil Chromatographic Data
Authors: Su Mingran , Zhang Anan , Gong Zemin
Published: July 2024

As one of the most important equipment in the operation of power system, ensuring the safe and stable operation of power transformer is a prerequisite for ensuring the normal supply of power grid. The failure of the power transformer will lead to the interruption of the power supply of the power grid and cause huge losses to the national economy. With the rapid development of China’s power grid scale and the continuous improvement of the intelligent construction of modern power system, the number of power equipment such as transformers is increasing. Therefore, it is necessary to make timely and accurate judgment on the status of key power transformation and distribution equipment in the power system, and grasp the operation of electrical equipment in real time, so as to ensure the reliability of power supply in the power system. This paper takes 220kV oil-immersed transformer as the research object. This paper considers the problems and characteristics of the current transformer fault diagnosis methods. By making full use of dissolved gas analysis (DGA) information in oil, a method for diagnosing faults in electrical transformers based on particle swarm optimization and generalized regression neural networks has been proposed. The simulation comparison experiment is carried out to select the most suitable transformer intelligent diagnosis method based on oil chromatographic data.
An Identity Authentication Method Of Configuration Terminal Based On Audio Feature Recognition In Smart Distribution Network
Authors: Qiao Hong , Wang Kaiyi , Long Yanbo , Huang TanLong , Xu Xianyong , Liu Shuai
Published: July 2024

A smart distribution network contains a large number of data acquisition terminals used to monitor the operation status of the distribution network and control the operation parameters, some of which are located in outdoor and other unsafe environments. If the attacker operates and configures the distribution network terminal by pretending to be a legitimate configuration device, it will become a springboard to infiltrate the main station of the internal network or misreport fault information, which may result in the leakage of sensitive data and even destroy the running state of the equipment. Identity authentication is the first line of defense to ensure the safe and stable operation of equipment. At present, the commonly used identity authentication technologies such as certificate authentication and key authentication have certain security vulnerabilities at different levels, which make it increasingly difficult to prevent the ever-changing network attack technology. According to the characteristics of physical unclonable facility (PUF), which is used to describe the hidden characteristics of the device and is directly related to the hardware, this paper proposes a method to authenticate the validity of the power distribution network configuration terminal based on the audio feature, which collects the frequency response characteristics of the hardware from the audio sensor of the configuration device as the identification information to identify the validity of the configuration device.
Conversion of Solar Irradiance to Photovoltaic Power with Hybrid Model Chains
Authors: Xia Han , Gao Fan , Wang Wenting , Liu Bai , Zhang Hao , Yang Dazhi
Published: July 2024

Accurate solar resourcing and forecasting depend upon the ability to convert weather forecasts to photovoltaic (PV) power forecasts, which remains challenging till this day. This study explores the fusion of physical model chains and machine learning, to achieve improved irradiance-to-power conversion. The outcomes of some well-tested steps of a model chain are used as input features of machine learning models, so as to form a hybrid model with high precision and wide applicability. Within this framework, a comparative analysis is conducted among three potential machine-learning models, including the long short-term memory (LSTM) network, k-nearest neighbors, and gradient boosting regressor. The results indicate that the physical-LSTM hybrid model exhibits superior performance to other options, reaching a correlation coefficient of 0.997. In cases where specific modeling parameters are unavailable, the hybrid model can mitigate the reliance on PV design parameters while gaining a notable increase in irradiance-to-power conversion accuracy, thereby substantiating a robust underpinning for PV grid connection.
Virtual Power Plant Response Strategy Considering Dynamic Aggregation of Different Flexible Resources
Authors: Wu Chang , Fang Lue , Yang Tao , Zhang Feng , Qiu Yutao
Published: July 2024

Aggregate and adjust distributed resources, the virtual power plant realizes the collaborative optimization of different forms of electric energy, which greatly improves the flexibility of the power system. Considering the flexibility of distributed resources, this paper designs the active power and frequency regulation modes of virtual power plants, and proposes a response strategy for dynamic resource aggregation of virtual power plants. Firstly, the distributed energy resources of virtual power plants are classified, and their dynamic characteristics are fully considered for dynamic aggregation, and the active power and based on these characteristics, a frequency regulation model is established. Secondly, according to the real-time operation status of sampled distributed resources, a response prediction model of virtual power plant based on dynamic resource aggregation was proposed. Finally, taking the 35kV substation workbench as an example, the response effect of the virtual power plant at different times of a typical day is verified.
Fault Condition Testing of Photovoltaic Inverter Controller Based on Active Support Technology using Hardware-In-the-Loop in RTDS
Authors: Li Shengnan , Hu Yun , He Xin , Zhu Yihua , He Tingyi , Tu Liang , Deng Can , Luo Chao , Su Mingzhang , Zeng Guanming
Published: July 2024

Photovoltaic power generation is an important component of sustainable power generation and has been widely utilized. Grid connected inverters are key equipment in photovoltaic integrated systems, which directly affect the stability of the system. In this paper, the transient model of photovoltaic inverter controller based on active support technology is derived. The transient mathematical model and corresponding self-closing loop control strategy are analyzed. Based on the RTDS, a hardware controller semi-physical simulation platform is established to simulate and test photovoltaic inverters under different fault and control methods. Finally, the simulation data obtained from the self-closing loop control method and the hardware control method are compared to verify the stability and reliability of the photovoltaic inverter hardware controller.
Research on Transformer Multiple Fault Detection Based on Pulse Coupled Injection
Authors: Jin Yuhui , Liu Jiangnan , Cai Linglong , Ma Zhiqin , Chen Yu , Hu Wei , Liu Yu
Published: July 2024

The fault diagnosis method of winding deformation based on pulse coupling injection is becoming more and more popular due to its advantages of online detection. In order to further improve the method, a pulse generator with adjustable parameters is developed in this paper to provide stable excitation. Its amplitude is adjustable from 600v to 5000v, pulse width is adjustable from 100 to 1000ns, and frequency is adjustable from 1 to 20kHz. In the diagnosis of winding deformation, the current research mainly focuses on the single deformation fault, and rarely involves the mixed deformation fault. Therefore, based on the pulse coupling injection method, field experiments are carried out to verify the feasibility of the method and find out the important reasons affecting the curve. At the same time, the detection experiment of multi-winding deformation fault superposition of a transformer is carried out, and the RVM frequency divider is used to accurately diagnose the mixed fault types of transformer windings.
Analysis of AC Filter Tripping Accident based on UHV Converter Station
Authors: Ai Ye , Bi Ruixuan , Ma Mengchao , Li Pei , Chen Lina , Li Haifeng
Published: July 2024

An AC filter tripping accident occurred in a converter station of the North China Power Grid in 2019, which seriously affected the safe and stable operation of the power grid. In this paper, combined with the configuration of the AC filter in the converter station and the principle of capacitor unbalance protection, the tripping mechanism of the AC filter is explained. It is considered that the direct cause of the tripping of the AC filter is the short-circuit discharge phenomenon between the layers caused by the dead trees (grass) branches on the capacitor tower, which causes the instantaneous fault between the layers of the low-voltage capacitor, and finally leads to the action of the capacitor unbalance protection. From the perspective of operation and maintenance, some practical preventive measures are put forward, which will help to improve the safety of AC filter operation in the future, and then improve the reliability of DC transmission system, especially during the peak summer, peak winter and special power protection period, to ensure that there will be no fluctuation in DC load transmission and protect the safe and stable operation of power grid.
Collaborative Planning of Energy Storage System Considering Peak Regulation Demand and Renewable Energy Integration
Authors: Pan Dong , Wang Xuli , Yang Xin , Shi Tiancheng , Shi Dajun , Chen Zhu
Published: July 2024

The capacity of renewable energy integrated into the grid is steadily expanding, necessitating strategic planning of energy storage systems (ESS). Such planning is pivotal not only for reducing peak load shaving but also for augmenting the grid’s capacity to accommodate renewable energy sources. In this manuscript, an ESS planning scheme considering peak regulation demand is proposed. The outer model of this scheme constitutes a multi-factor optimization model with the net income of ESS and the new renewable energy acceptance index. The inner model is an optimal dispatching model, which aims at minimizing the system peaking operation cost, optimizes the renewable energy acceptance of the system, and obtains the charging and discharging power and energy storage configuration capacity of the ESS. Finally, the improved IEEE-30 bus system is used for simulation, and the results verify the feasibility and effectiveness of the proposed method.
Voltage-Coupled Cascading Trip-off within Permanent Magnet Synchronous Generator Based Wind Farm during Low Voltage Ride Through
Authors: Zhang Yujiang , Ding Zewen , Zhang Pengcheng , Zou Xin , Yao Ruizhe , Wang Fei
Published: July 2024

With the increasing penetration of renewable energy, power electronic interfaced devices have become dominant in power system. It is necessary to investigate the dynamic process of the power grid in a smaller time scale. In case of failing in low voltage ride through (LVRT), the traditional method that treats the response of permanent magnet synchronous generator (PMSG) based wind farm as a one-time trip-off cannot accurately model the cascading failures in such a new-type power system. This paper focuses on this issue and conducts a detailed study of the dynamic process in a PMSG wind farm during LVRT. Firstly, we reveal an evolution mechanism of voltage-coupled cascading trip-offs in PMSG wind farm. Then, the wind farm based on PMSG is modeled in DIgSILENT/PowerFactory. The model takes into account the voltage losses on the power collection line inside the wind farm, and each wind turbine includes an independent control model. Finally, by simulation, we obtain the principle on cascading failures of internal wind turbines in the wind farm, and confirm the interaction mechanism between turbines as well as the detailed process of cascading failures.
Probability and Severity Based Overvoltage Risk Analysis Considering Large-Scale DG Access
Authors: Dong Yichao , Zhang Tianyu , Yan Dawei , Luo Tao , Song Jia , Lei Zheng , Li Yuanyuan , Zhang Dezheng , Chen Yiwen , Luo Fengzhang
Published: July 2024

With the rapid increase of distributed generation (DG) in the distribution network (DN), the analysis of DG maximum bearing capacity (DGMBC) is paid more attention. However, the existing methods can not precisely simulate the overvoltage risk concerning occurrence probability and severity. To this end, the overvoltage scenario classification method and overvoltage severity coefficient correction method are proposed in this paper, which can effectively reflect the real overvoltage risk in DN. The IEEE 33-bus test feeder is used to compare the calculation results of overvoltage risk with other methods.
Research on Inverter Control Strategy Based on FPGA
Authors: Wang Haiteng , Li Ruixiang , Zhou Shuqing , Chen Jie
Published: July 2024

This study adopts a composite repetitive controller strategy in a three-phase four-wire circuit, combining proportional resonance and repetitive control, which effectively suppresses harmonics and improves system performance. At higher switching frequencies, FPGA is used to achieve efficient control to ensure system stability and performance. This research provides new ideas for improving the performance of on-board inverters, especially in terms of high-speed control, nonlinear load and harmonic processing. SiC devices and composite control strategies provide more sustainable solutions for future rail transit systems.
Analysis of Parameter Sensitivity to Overvoltage under DC Commutation Failure
Authors: Dong Xuetao , Duan Naixin , Huo Chao , Rong Xiuting , Xi Gongwei , Xu Kaiwen
Published: July 2024

In recent years, the growing integration of renewable energy sources into power systems has highlighted the significance of enhancing the grid’s capacity to accommodate these resources efficiently. Direct Current (DC) transmission stands out as a pivotal solution to bolster the integration of renewable energy. This study delves into the critical issue of overvoltage occurrences at the sending end, particularly triggered by failures in DC commutation. Through the development of a comprehensive PSCAD electromagnetic simulation model encompassing synchronous machines, centralized renewable energy sources, along with DC components, the research rigorously investigates the intricacies of DC commutation failures. Specifically, it explores their underlying mechanisms responsible for inducing overvoltage at the sending end. Furthermore, the paper undertakes an extensive analysis of the voltage dynamic processes and their associated sensitivity factors, shedding light on crucial aspects of grid stability and resilience in the face of evolving energy landscapes.
Research on Multi-Objective Optimization Scheduling Strategy for Cascaded Small Hydropower Stations Based on Improved HBA
Authors: Liu Li , Tan Jianzhong , Li Tingting , Chen Xizhi , Zeng Qiancheng
Published: July 2024

Effective optimization scheduling strategy is the premise and key to improving the power generation and capacity benefits of cascade small hydropower stations (CSHS). However, the power generation of CSHS is significantly affected by complex hydraulic and electrical constraints. To effectively solve this problem, an improved honey badger algorithm (HBA) is proposed by updating the mutation strategy and introducing non-dominated sorting to achieve the multi-objective optimization scheduling solution of CSHS. The following improvements have been made to the standard HBA: Firstly, the Tent chaotic mapping is applied to the population initialization stage, its strong ergodicity and randomness ensure the randomness of the initialization stage and improve the global search ability of CSHS scheduling. Secondly, the powerful optimization ability and fast convergence speed of the Golden-Sine strategy make updating and mutation more efficient, greatly enhancing the local search ability of CSCH scheduling. And then combining the non-dominated sorting of the non-dominated sorting genetic algorithm-II (NSGA-II), an improved multi-objective Honey Badger Algorithm (IMOHBA) is further proposed to achieve multi-objective solutions for CSCH scheduling. Finally, abundant field experiments were tested for validation. The results expressed that compared to other algorithms, the effect of IMOHBA in CSHS scheduling can further increase power generation, while also improving the peak shaving ability of CSHS.
Study on Breakdown Characteristics and Attenuation Characteristics of Air Mixed Gas
Authors: Yu SiNan , Lin Xin , Zhang Bo , Zhao YanZhe
Published: July 2024

Nowadays, the global demand for environmental protection and energy saving is getting higher and higher. In the past, SF6 gas was regarded as an environmentally unfriendly gas in the circuit breaker with SF6 gas as the insulating medium. In order to save energy and reduce emissions, this paper uses clean and environmentally friendly air as the arc extinguishing medium. The gas mixture studied contains N2, O2 and CO2. Through two approximate values of Boltzmann equation, we obtain the electron energy distribution function of air mixed gas under different electric field reduction conditions. By studying the changes of ionization and adsorption coefficients of particles under various collision conditions, we obtained the conversion breakdown field strength (E/N) Cr of air mixture. An arc attenuation model is built to characterize the arc attenuation characteristics using the prior transport characteristics as input. The arc attenuation process is broken down into three steps: heat recovery, pre-ignition, and arcing. All of these phases are determined by the changes in axial temperature and arc conductance over time. Analysis is done on the air and nitrogen thermal recovery and pre-dielectric recovery phases. This study explores the use of clean dielectrics to ensure optimum performance of primary equipment in the power system, based on current circumstances.
Influence Of Transmission Lines On Buried Pipelines Under Various Operation Conditions
Authors: Hu Xin , Wang Yifei , Xi Xiaojuan , Guo Yanxun
Published: July 2024

Electromagnetic interference from transmission lines to adjacent pipelines can adversely affect the safe functioning of these pipelines. In this paper, a simulation model that the transmission line crosses the buried pipeline is established in CDEGS software. The influence of current amplitude, soil resistivity, and cross angle on the electromagnetic interferences are analyzed under different operation conditions of transmission line, including normal operation, short circuit fault and lightning fault. The analysis results are as follows: the soil resistivity has a great influence on the coating withstand voltage under the short circuit fault and lightning fault condition; with the increase of the current amplitude and the cross angle, the coating withstands voltage increases and decreases, respectively. These results indicate that, during construction, it is advisable to avoid parallel layouts of transmission lines and pipelines. Pipelines ought to be built in regions characterized by lower soil resistivity.
Switching Control for Voltage Balancing of Lithium Batteries
Authors: Meng Qianqian , Yan Jiahao , Zhu Ren , Li Heng
Published: July 2024

Battery system consists of many battery cells or modules with different characteristics, in order to achieve reliable, efficient and long time use of the battery system, and to avoid the performance difference between single cells due to manufacturing and aging, we need to balance the voltage of single cells. At present, the research and development progress of battery balancing technology lags far behind the development of battery technology. In order to achieve effective balancing of single cells in a battery pack, we propose a “switching tube + resistor” type passive balancing technology for single cell voltage, which is a method to distribute the switching time of the shunt circuit according to the voltage of each single cell, so as to control the charging current of single cells and achieve battery voltage balancing, but The traditional passive balancing method will make the battery management system unstable therefore it is difficult to put it into use, this paper proposes a new switching control algorithm to overcome the problem of passive balancing making the BMS unstable, thus providing an effective balancing method that can be used practically in the use of lithium batteries.