bluuebunny/crossref_metadata_2025 huggingface dataset:
Meta-autoencoder-based zero-shot learning for insulation defect diagnosis in gas-insulated switchgear
Authors: Wang Yanxin , Yan Jing , Yang Zhou , Wang Zhanbei , Wang Jianhua , Geng Yingsan
Published: March 2023

Data-driven methods are the primary methods of training models for the diagnosis of insulation defects in gas-insulated switchgear (GIS). Due to complicated operating environments, target samples are not available for training sometimes, leading to insufficient feature learning. Therefore, a meta-autoencoder-based zero-shot learning (MAZL) method is proposed for the diagnosis of GIS insulation defects. First, the visual features of insulation defects’ signals are extracted by a convolutional neural network. Next, the mapping between visual and semantic spaces is learned by semantic autoencoder (SAE). For SAE, the triplet loss is adapted to align semantic information, and unknown class semantic constraints are used to alleviate the domain offset. Finally, a nearest-neighbor algorithm is used to achieve zero-sample diagnosis. In model training, episode training is introduced to make the MAZL model learn a more discriminative semantic prototype, which alleviates classification deviations. The MAZL achieved a diagnostic accuracy for single and multi-source GIS insulation defects of 96.215% and 90.41% without using test classes for training, respectively. This finding provides ideas for the diagnosis of new GIS insulation defects.
Vortex merging in ion phase-space induced by two-ion decay instability
Authors: Liu D J , Wang Qing , Yang T , Cheng R J , Li X M , Li X X , Zhang S T , Lv S Y , Huang Z M , Wang Qiang , Liu Z J , Cao L H , Zheng C Y
Published: March 2023

We theoretically and numerically study the merger phenomenon of the ion-phase vortex structure in hydrogen plasma. The results indicate that the merging of vortex structures during the nonlinear evolution of ion-acoustic waves (IAW) is mainly due to two-ion decay (TID) instability. When the daughter IAWs of the TID grow to be comparable to the fundamental mode, vortex merging will occur. Furthermore, the vortex merging can abruptly convert the significant energy of the fundamental mode into subharmonic energy, resulting in saturation for the TID of the fundamental mode. After several vortex-merging processes, the system eventually evolves into a turbulent state. In particular, the TID growth rate has been improved by considering two additional second-order coupling terms in this paper, which agree much better with the simulation results. Finally, the importance of the electron kinetic effects in the TID process is also presented by comparing hybrid-Vlasov and full-Vlasov simulations.
Photon energy-resolved velocity map imaging from spectral domain ghost imaging
Authors: Wang Jun , Driver Taran , Allum Felix , Papadopoulou Christina C , Passow Christopher , Brenner Günter , Li Siqi , Düsterer Stefan , Tul Noor Atia , Kumar Sonu , Bucksbaum Philip H , Erk Benjamin , Forbes Ruaridh , Cryan James P
Published: March 2023

We present an approach that combines photon spectrum correlation analysis with the reconstruction of three-dimensional momentum distribution from velocity map images in an efficient, single-step procedure. We demonstrate its efficacy with the results from the photoionization of the 2 p-shell of argon using the Free-electron LASer in Hamburg free-electron laser (FEL). Distinct spectral features due to the spin-orbit splitting of Ar

+

(
2

p

−
1

)

are resolved, despite the large average bandwidth of the ionizing pulses from the FEL. This demonstrates a clear advantage over the conventional analysis method, and it will be broadly beneficial for velocity map imaging experiments with FEL sources. The retrieved linewidth of the binding energy spectrum approaches the resolution limitation prescribed by the spectrometers used to collect the data. Our approach presents a path to extend spectral-domain ghost imaging to the case where the photoproduct observable is high-dimensional.
Research on the design of phononic crystal shaft bandgaps based on lumped mass method
Authors: Shi Xiaona , Liu Hongyi , Wang Xuerui , Zhao Lei , Mou Di , He Qiang , Lv Chenghao , Wang Kelong , Wang Xuejing
Published: March 2023

Phononic crystals tend to mature in the research of forward problems due to their unique bandgap characteristics, but it is difficult to realize reasonable parameter design at specific bandgap frequencies in practical engineering applications. Thus, based on the lumped mass method, a research method for the inverse problem of phononic crystal shaft bandgaps is proposed in this paper. On the basis of the discretization model, the relationship between polynomials and the characteristic of bandgaps is discussed through derivation of the dispersive polynomial, and the feasible regions of the corresponding parameters are solved according to the bandgap existence criterion established by the characteristic rules for analytical verification. The results show that the bandgap existence criterion for frequency points and frequency bands can accurately and effectively invert the relevant parameters that meet the requirements, and the method is of great practical significance for promoting the development of phononic crystal shaft parameter design under the target bandgap in engineering applications.
Probing Lorentz-violating electrodynamics with CMB polarization
Authors: Caloni L. , Giardiello S. , Lembo M. , Gerbino M. , Gubitosi G. , Lattanzi M. , Pagano L.
Published: March 2023

We perform a comprehensive study of the signatures of Lorentz violation in electrodynamics
on the Cosmic Microwave Background (CMB) anisotropies. In the framework of the minimal Standard
Model Extension (SME), we consider effects generated by renormalizable operators, both CPT-odd and
CPT-even. These operators are responsible for sourcing, respectively, cosmic birefringence and
circular polarization. We propagate jointly the effects of all the relevant Lorentz-violating
parameters to CMB observables and provide constraints with the most recent CMB datasets. We bound
the CPT-even coefficient to kF,E+B
< 2.31 × 10-31 at 95% CL. This improves previous
CMB bounds by one order of magnitude. The limits we obtain on the CPT-odd coefficients,
i.e. |k
(3)
(V)00| < 1.54 × 10-44 GeV and |kAF
| < 0.74 ×
 10-44 GeV at 95% CL, are respectively one and two orders of magnitude stronger than
previous CMB-based limits, superseding also bounds from non-CMB searches. This analysis provides
the strongest constraints to date on CPT-violating coefficients in the minimal SME from
CMB searches.
Cosmological imprints of SUSY breaking in models of sgoldstinoless non-oscillatory inflation
Authors: Heurtier L. , Moursy A. , Wacquez L.
Published: March 2023

In supergravity, the dynamics of the sgoldstino – superpartner of the goldstino superfield associated with the breaking of supersymmetry at low energy – can substantially modify the dynamics of inflation in the primordial Universe. So-called sgoldstinoless models assume the existence of a nilpotency constraint S
2 = 0 that effectively removes the sgoldstino from the theory. Such models were proposed to realise non-oscillatory inflation scenarios with a single scalar field, which feature a long period of kination at the end of inflation, and therefore a non-standard post-inflationary cosmology. Using effective operators, we propose models in which the sgoldstino is stabilized close to the origin to reproduce the nilpotent constraint. We show that small sgoldstino fluctuations may lead to a sizeable back-reaction on the cosmological history. We study the effect of this back-reaction on the inflation observables measured in the cosmic microwave background and confront the model to a series of constraints including limits on ΔN
eff. We show that the peculiar form of the potential in the large supersymmetry breaking scale limit can generate peaks in the scalar power spectrum produced from inflation. We study how certain perturbation modes may re-enter the horizon during or after kination and show that a large supersymmetry breaking scale may lead to the formation of primordial black holes with various masses in the early Universe.
Theoretical analysis of the optical rotational Doppler effect under atmospheric turbulence by mode decomposition
Authors: Ma 马 Sheng-Jie 圣杰 , Xu 徐 Shi-Long 世龙 , Dong 董 Xiao 骁 , Zhang 张 Xin-Yuan 鑫源 , Chen 陈 You-Long 友龙 , Hu 胡 Yi-Hua 以华
Published: March 2023

The optical rotational Doppler effect associated with orbital angular momentum provides a new means for rotational velocity detection. In this paper, we investigate the influence of atmospheric turbulence on the rotational Doppler effect. First, we deduce the generalized formula of the rotational Doppler shift in atmospheric turbulence by mode decomposition. It is found that the rotational Doppler signal frequency spectrum will be broadened, and the bandwidth is related to the turbulence intensity. In addition, as the propagation distance increases, the bandwidth also increases. And when

C
n
2

≤
5
×

10

−
15

m−2/3 and 2z ≤ 2 km, the rotational Doppler signal frequency spectrum width d and the spiral spectrum width d
0 satisfy the relationship d = 2d
0–1. Finally, we analyze the influence of mode crosstalk on the rotational Doppler effect, and the results show that it destroys the symmetrical distribution of the rotational Doppler spectrum about 2l⋅Ω/2π. This theoretical model enables us to better understand the generation of the rotational Doppler frequency and may help us better analyze the influence of the complex atmospheric environment on the rotational Doppler frequency.
Thickness-dependent exciton relaxation dynamics of few-layer rhenium diselenide
Authors: Huo Chang-Fu , Yun Tiantian , Yan Xiao-Qing , Liu Zewen , Zhao Xin , Xu Wenxiong , Cui Qiannan , Liu Zhi-Bo , Tian Jian-Guo
Published: March 2023

Rhenium diselenide (ReSe2) has gathered much attention due to its low symmetry of lattice structure, which makes it possess in-plane anisotropic optical, electrical as well as excitonic properties and further enables ReSe2 have an important application in optoelectronic devices. Here, we report the thickness-dependent exciton relaxation dynamics of mechanically exfoliated few-layer ReSe2 flakes by using time-resolved pump–probe transient transmission spectroscopies. The results reveal two thickness-dependent relaxation processes of the excitons. The fast one correlates with the exciton formation (i.e., the conversion of hot carriers to excitons), while the slow one is attributed to the exciton recombination dominated by defect-assisted exciton trapping besides photon emission channel. The decrease of scattering probability caused by defects leads to the increase of fast lifetime with thickness, and the increase of slow lifetime with thickness is related to the trap-mediated exciton depopulation induced by surface defects. Polarization-dependent transient spectroscopy indicates the isotropic exciton dynamics in the two-dimensional (2D) plane. These results are insightful for better understanding of excitonic dynamics of ReSe2 materials and its application in future optoelectronic and electronic devices.
Velocity analysis of supersonic jet flow in double-cone ignition scheme
Authors: Zhu 朱 Zhong-Yuan 仲源 , Zhang 张 Cheng-Long 成龙 , Li 李 Ying-Jun 英骏
Published: March 2023

In the double-cone ignition schemes (DCIS), the deuterium–tritium target shell is ablated and compressed by a high-power nanosecond laser in Au-cones to generate plasmas. Under the actions of spherically symmetric compression and acceleration along the Au cone, they will be ejected out of the cone mouth and collide with each other. The plasmas experience conversion from kinetic energy to internal energy at the vertex of the geometric center of two Au cones that are symmetric to each other, because of which high-density fusion plasmas are preheated. This key physical process has undergone experimental verification on the Shenguang-II upgraded facility in China. Apparently, the improvement and optimization of the velocity of plasmas in hypersonic jet flow at the cone mouth are crucial for the success of the DCIS. In the DCIR7 experiment of the Shenguang-II upgraded facility, a velocity yield of approximately 130–260 km/s was achieved for the plasmas at the cone mouth, with a result of nearly 300 km/s based on numerical simulation. In this paper, theoretical analysis is performed as regards the process, in which target shells are ablated and compressed by laser to generate high-velocity plasmas ejected through jet flow. Based on this analysis, the formula for the velocity of plasmas in supersonic jet flow at the cone mouth is proposed. This study also provides measures that are more effective for improving the kinetic energy of plasmas and optimizing energy conversion efficiency, which can serve as theoretical references for the adjustment and optimization of processes in subsequent experiments.
Gravastar in the framework of symmetric teleparallel gravity*
Authors: Pradhan Sneha , Mandal Sanjay , Sahoo P.K.
Published: March 2023

We present a novel gravastar model based on the Mazur-Mottola (2004) method with an isotropic matter distribution in

gravity. The gravastar, which is a hypothesized substitute for a black hole, is built using the Mazur-Mottola mechanism. This approach allows us to define the gravastar as having three stages. The first one is an inner region with negative pressure; the next region is a thin shell that is made up of ultrarelativistic stiff fluid, and we studied the proper length, energy, entropy, and surface energy density for this region. Additionally, we demonstrated the possible stability of our suggested thin shell gravastar model through the graphical study of the surface redshift. The exterior Schwarzschild geometry describes the outer region of the gravastar. In the context of

gravity, we discovered analytical solutions for the interior of gravastars that are free of any type of singularity and the event horizon.
Effect of radiation exposure on function human body by CBC parameter for workers in nuclear medicine field
Authors: Lafta H A , Allawi R A , Mahmood M A , Hammudi R A , Al Hasani M H , Sharhan S I , Abbas I M
Published: March 2023

In this study, eight cases of workers in gamma camera scans and Positron Emission Tomography (PET/CT scan) fields (employed for various medical diagnoses) had their complete blood counts (CBCs) assessed. From the first hour of work until the last, the investigation of radiation’s impact on hematology was ongoing. By using a personal dose meter (Geiger Badge), the radiation exposure reading for a whole workday is directly recorded in (μSv). The study concluded that while the number of WBC count increased for all workers after radiation exposure, the number of RBC count decreased after exposure, suggesting that RBC amount may be a reliable indicator of exposure degree.
Measuring radioactive content and the effective radiation doses of natural origin in most consumed foodstuffs in the city of Kut – Iraq
Authors: Aleqaby Mohammed Wasfi T , Dwaich Zal-Attabi Hadi
Published: March 2023

Natural radioactive materials known by the term (NORM) are among the most important sources of radiation that can be transmitted to humans through eating foodstuffs. Therefore, researchers took care to study the levels of this type of radiation. In the current study, the levels of radioactivity were determined for the three most important natural radioactive elements, uranium (U-238), thorium (Th-232), and potassium (K-40) in (29) of the most consumed food samples collected from Wasit Governorate Markets. A gamma-ray spectroscopy system consisting of a sodium iodide activated thallium detector (NaI)Tl with dimensions of “3×3” and electronic units attached to it was used in this study. The results obtained from the studied samples showed the concentrations of (U-238, Th-232, and K-40), the value of the annual effective dose, the equivalent concentration of radium Raeq-226, and external and internal risk factors indicated that all concentrations of the radioactive elements targeted in the study were within the permissible limits despite the discrepancy in the values of the concentrations of these elements according to the samples.
A novel medical image enhancement technique based on hybrid method
Authors: Khudhair Kifah T , Najjar Fallah H , Waheed Safa Riyadh , Al-Jawahry Hassan M , Alwan Haneen H , Al-khaykan Ameer
Published: March 2023

Medical images are a specific type of image that can be used to diagnose disease in patients. Critical uses for medical images can be found in many different areas of medicine and healthcare technology. Generally, the medical images produced by these imaging methods have low contrast. As a result, such types of images need immediate and fast enhancement. This paper introduced a novel image enhancement methodology based on the Laplacian filter, contrast limited adaptive histogram equalization, and an adjustment algorithm. Two image datasets were used to test the proposed method: The DRIVE dataset, forty images from the COVID-19 Radiography Database, endometrioma-11, normal-brain-MRI-6, and simple-breast-cyst-2. In addition, we used the robust MATLAB package to evaluate our proposed algorithm’s efficacy. The results are compared quantitatively, and their efficacy is assessed using four metrics: Peak Signal to Noise Ratio (PSNR), Mean Square Error (MSE), Contrast to Noise Ratio (CNR), and Entropy (Ent). The experiments show that the proposed method yields improved images of higher quality than those obtained from state-of-the-art techniques regarding MSE, CNR, PSNR, and Ent metrics.
Kaon processes in general 2HDM
Authors: Kumar Girish
Published: March 2023

We discuss new physics (NP) contributions to kaon mixing parameter εK
, direct CP violation parameter ε′/ε of K → ππ, and rare decays

K
+

→

π
+

ν

ν
¯

,

K
L

→

π
0

ν

ν
¯

and KL,S
→ μ+μ−
in the context of general two Higgs doublet model. We focus on contributions of top quark related exotic couplings, and show that simultaneous presence of flavor conserving and flavor violating interactions can lead to large NP effects in kaon sector, while being consistent with the stringent constraints from B physics observables such as

B

s
(
d
)

−

B
¯

s
(
d
)

mixing, Bs
→ μ+μ−, and b → sγ. We stress on the importance of correlations between εK
,

K
+

→

π
+

ν

ν
¯

and Bs
→ μ
+
μ
− that can be exploited to distinguish the parameter space corresponding to a light (sub-TeV) or heavy (TeV) scale charged Higgs boson.
A new KS
→ πeν branching fraction measurement from KLOE-2
Authors: Lucia Erika De
Published: March 2023

The KLOE-2 Collaboration continues the KLOE long-standing tradition of flavour physics precision measurements in the kaon sector with a new KS
→ πeν branching fraction measurement with 1.63 fb−1 KLOE data acquired at the DAΦNE Frascati ϕ-factory. The strategy to achieve this new result has been presented together with the combination with our previous BR(KS
→ πeν) measurement, based on an independent data sample, which allows the total precision to be improved by almost a factor of two, and a new derivation of f
+(0)|Vus
|.
Measurement of the rare decay K
+ → π
+
μ
+
μ
− at the NA62 experiment
Authors: Koval Michal
Published: March 2023

The NA62 experiment at CERN reports results from the study of the flavour-changing neutral current decay K
+ → π
+
μ
+
μ
− using a data sample recorded in 2017–2018 with a dedicated pre-scaled di-muon trigger. The sample comprises about 28k signal events with negligible background contamination, and the presented results include the most precise determination of the corresponding branching fraction and the form factor parameters.
A direct test of T, CP and CPT symmetries in transitions of neutral kaons with KLOE data
Authors: Domenico Antonio Di
Published: March 2023

Direct tests of T, CP, CPT symmetries in transitions processes of neutral kaons are briefly reviewed. The exchange of in and out states required for a genuine test involving time-reversal is implemented exploiting the entanglement of

K
0

K
¯

0

pairs produced at a ϕ-factory.

A data sample collected by the KLOE experiment at DAΦNE corresponding to an integrated luminosity of about 1.7 fb−1 is analysed to study the ϕ → KSKL → π
+
π
−
πeν and ϕ → KSKL → πeν 3π
0 processes, and to perform the first direct tests of T and CPT symmetries in kaon transitions with a precision of few percent, and to observe CP violation with this novel method.
Search for the pair production of dark particles in

KL0

decays at KOTO
Authors: Lin Chieh
Published: March 2023

We present the first search for the pair production of dark particles X in

K
L
0

decays assuming that X decays into two photons promptly. No signal was observed in the mass regions of 40 − 110 MeV/c2 and 210 − 240 MeV/c2. This leads to

B
(

K
L
0

→
X
X
)
<
(
1
−
4
)
×

10

−
7

and

B
(

K
L
0

→
X
X
)
<
(
1
−
2
)
×

10

−
6

at the 90% confidence level for the two mass regions, respectively.
HIKE: High Intensity Kaon Experiments at the CERN SPS
Authors: Moulson Matthew
Published: March 2023

The availability of high intensity kaon beams at the CERN SPS North Area gives rise to unique possibilities for sensitive tests of the Standard Model in the quark flavor sector. Precise measurements of the branching ratios for the flavor-changing neutral current decays

K
→
π
ν

ν
−

can provide unique constraints on CKM unitarity and, potentially, evidence for new physics. Building on the success of the NA62 experiment, plans are taking shape at CERN for a comprehensive program that will include experimental phases to measure the branching ratio for

K
+

→

π
+

ν

ν
−

to ∼5% and to

K
L

→

π
0

ν

ν
−

to ∼20% precision. These planned experiments would also carry out lepton flavor universality tests, lepton number and flavor conservation tests, and perform other precision measurements in the kaon sector, as well as searches for exotic particles in kaon decays. We overview the physics goals, detector requirements, and project status for the next generation of kaon physics experiments at CERN.
Online Event Selection and GPU-based Waveform Compression at the High Level Trigger of the KOTO Experiment
Authors: Gonzalez Mario
Published: March 2023

The Data Acquisition (DAQ) system of the KOTO experiment is currently undergoing a major upgrade, following an also ongoing accelerator’s beam intensity upgrade. The throughput of the current DAQ is limited by the hardware, and different prescalings have to be applied to reduce the data rate to a manageable level. The DAQ upgrade aims to remove the hardware bottleneck, increasing the amount of data that reaches the high level trigger system. The new high level trigger will make use of parallelization over CPU and GPU threads to perform event reconstruction, selection, and compression, to eventually allow for more variate physics searches in KOTO.
Development of a PMT base used for the new charged veto detector in the J-PARC KOTO experiment
Authors: Kitagawa Ayumu
Published: March 2023

The KOTO experiment searches for the rare decay

K
L

→

π
0

ν

ν
¯

at J-PARC. The largest background in the data collected in 2016-2018 was caused by decays of K
±. To detect K
±, we are developing an in-beam charged veto detector to be installed upstream of the KOTO detector. It uses a 0.2mm-thick thin plastic scintillator. The escaped light is reflected and collected by a 12-μm-thick aluminized mylar, and read out by an array of PMTs placed outside the beam. We newly developed PMT bases to be used for this detector. Based on an electron beam test, we expect the K
± background to be reduced by more than a factor 100. We plan to install this detector in the KOTO beam line, in December 2022.
Generic model of heavy new physics for the kaon systems
Authors: Moldanazarova Ulserik
Published: March 2023

Various precision observables, such as flavour changing decays, are loop induced in the standard model and their renormalisation involves cancellations between purely bosonic and fermionic interactions. Here, I will show how perturbative unitarity constraints can be used to derive renormalised matching conditions for generic theories. These general results comprise the matching conditions for specific models that address current flavour anomalies and can be used for phenomenological analyses for rare and CP violating kaon decays.
Effective theory for universal seesaw model and FCNC
Authors: Morozumi Takuya , Adam Apriadi Salim , Kawamura Yuta , Panuluh Albertus Hariwangsa , Shimizu Yusuke , Yamamoto Kei
Published: March 2023

We study the quark sector of the universal seesaw model with SU(2)
L
× SU(2)
R
× U(1). The model incorporates the seesaw mechanism with the vector-like quarks (VLQs). The purpose of this work is to study the model with the effective theory. After integrating the heavy five VLQs, we derive the effective theory with four up-type quark and three down type quark. In this work, the FCNC of Z boson for top quark and top′ quark is derived.
Study of weak-basis invariants in the universal seesaw model using Hilbert series
Authors: Panuluh Albertus Hariwangsa , Morozumi Takuya
Published: March 2023

Universal Seesaw Model is a model which explains the mass hierarchy of the quark sector. This model introduces vector-like quarks. The top quark mass is generated in the electroweak scale and the other quark mass is generated using a seesaw-like mechanism. The invariant theory helps construct a weak-basis invariant. We study the weak-basis invariant (WBI) using Hilbert Series (HS) and apply it to the Universal Seesaw Model, particularly the one-generation case of the quark sector.
KL0→γ+darkphoton(γ¯)

Search at the J-PARC KOTO Experiment
Authors: Wu Tong
Published: March 2023

We present the study of massless dark photons in the decay of

K
L
0

→
γ

γ
¯

in the J-PARC KOTO experiment. The massless dark photon

(

γ
¯

)

is different from the massive dark photon because it does not mix directly with ordinary photons, but it could interact with SM particles through direct coupling with quarks. In some theoretical predictions, the

B
R
(

K
L
0

→
γ

γ
¯

)

can be as large as 𝒪(10-3), which is well within the sensitivity of KOTO. Because of the lack of kinematic constraints, searching for

K
L
0

→
γ

γ
¯

could be challenging, but the hermetic veto system of KOTO provides a unique opportunity to probe for this decay. We used three techniques to suppress the neutron background, based on machine learning, Fourier analysis, and both-end readout. We will present the background suppression result based on data collected in 2020.
Effect of interstitial nitrogen on bonding characteristics and electronic structure of high nitrogen steel
Authors: Ning Kai , Bai Di , You Xianxian , Zhang Hong , Liu Fengde
Published: March 2023

Interstitial nitrogen can significantly change the electronic structure and bonding characteristics of austenite, and has an important influence on the properties of austenite. The bonding properties and properties of high nitrogen steel with different nitrogen element ratios were calculated. The alloy model with different nitrogen content is established, and the properties of energy, density of states and elastic constant are calculated. Increasing the nitrogen content will reduce the density of states and energy, significantly improving the stability of the cell. The crystal cells with different nitrogen content meet the mechanical stability. With the increase of nitrogen content, the elastic modulus, Poisson’s ratio gradually decreases, strength, shear strain and deformation resistance increase, and plasticity and ductility decrease.
Wide-Frequency Range Voltage Monitoring Device for Current Transformer
Authors: Zhou Guowei , Chen Xin , Zheng Hong , Yin Jiaqi , Peng Chenguang
Published: March 2023

To optimize the online voltage monitoring technology of the power grid and realize real-time fault warning for the power grid and capacitive devices such as current transformers (CT), this paper proposes a wide-frequency range voltage monitoring method based on current transformers according to the idea of measuring the leakage current of capacitive devices to restore the line voltage. The method measures the current transformer leakage current to invert the bus voltage and uses a wide frequency range current sensor to meet the measurement of high-frequency waveforms. This paper designs a CT wide-frequency range voltage monitoring device based on this method and conducts field tests of the device’s measurement effects. Through the fault monitoring test and voltage monitoring test, it is verified that the monitoring device is fully functional and can achieve accurate monitoring of harmonics, end shield current, relative dielectric loss, high-frequency partial discharge, and bus-voltage with high amplitude and high frequency, which can provide support for fault analysis and insulation design improvement and is of great significance to ensure safe and stable operation of the power grid.
Research on Material Selection and Electromagnetic Characteristics of Composite Electromagnetic launcher
Authors: Li Gen , Shu Tao , Zheng Hanchao , Lin Chenjie , Zhang Pengxiang , Wang Yingying
Published: March 2023

The armature and rail thermal ablation caused by the current concentration phenomenon will affect the service life of the guideway during the operation of the compound four-rail electromagnetic emitter. With different rail materials simulated and analyzed using the finite element analysis method and the ANSYS software, the composite four-rail electromagnetic launcher’s current density distribution and electromagnetic field distribution were designed to optimize and improve the thermal ablation of the armature and rail of the composite electromagnetic launcher. The results show that the copper steel composite electromagnetic launcher can improve the current concentration and electromagnetic shielding ability.
A Method Based on Phase-shifting Carrier for Reducing DC-link Current Harmonics in Dual Three-phase PMSM Drive under Open-phase Conditions
Authors: Wang Qingzhe , Du Yanwei , Yang Guang , Liu Hongyang
Published: March 2023

The All-Electric of modern military equipment has become an important trend, in the field of aircraft the traditional servo control focus on the exact control of the motor. With the development of power electronics technology, a high-power motor has expanded into a multiphase kind which cast off the limitation of traditional three-phase motors. The multiphase motor has more control resources and fault-tolerant control ability under the fault condition, which has practical meaning for high safety and high-reliability applications in an airborne environment. The multiphase motor can be controlled by a series of phase-shift carriers, which can reduce DC current ripple more effectively than the traditional carrier-based pulse width modulation, but it needs to find the optimal phase shift angle. In this paper, the optimal carrier phase shift angle is analyzed mathematically which can be used for both under health and single open-phase fault of a dual three-phase motor, and the simulation result illustrates that the carrier phase shift method used in this paper has the DC current ripple optimization effect.
Simulation Research for Thermal Characteristics for Temperature Gradient of Three-core Cable Joint
Authors: Wang Shaohua , Wu Xuxiang , Cao Junping , Tao Ruixiang , Xia Rong , Zhao Jian , Li Xing , Yang Fan
Published: March 2023

Temperature is one of the important parameters of power cables with normal operation. In this article, the electromagnetic and thermal characteristics of three-core cable joints were investigated. And the core and surface temperature gradient were obtained with a three-core cable joint. The research results show that the core temperature of the center is about higher than 14 °C than the body part. The surface temperature is distributed as high at the center and low at the body. The surface fluctuation amplitude of the joint center temperature is about 10 °C. The maximum surface temperature gradient with the center can reach 1697 °C/m of cable joint. The results here should have potential application value in characteristics of electromagnetic-thermal coupling field under the action of internal defects of cable joint.
Study on electric field distribution of multi-layer dielectric under mixed voltage
Authors: Zhang Shiling
Published: March 2023

The combination of field and circuit analysis method is used. Taking the multilayer flat dielectric structure as an example, the electric field distribution law of multilayer dielectric under mixing and polarity reversal voltage is studied by using the electromagnetic field theory. Then, according to the actual situation, two typical multilayer dielectric structures are selected, equivalent circuit model is established, and multilayer dielectric equivalent circuit experiment is carried out. At the same time, the equivalent circuit is simulated and analyzed by using the circuit simulation to further analyze the distribution law of electric field under various voltages. On this basis, the finite element simulation is used to simulate the double-layer plate dielectric structure model, which verifies the applicability of the finite element simulation method in the calculation of AC/DC hybrid electric field. Finally, the structural model of ±800kV converter outlet bushing is established, and the AC, DC, AC and DC superposition and polarity reversal voltage are loaded respectively. The electric field distribution in each medium of the complex insulation structure is calculated and analyzed accordingly. The results show that the finite element simulation method is simple and effective, and it is feasible to study the electric field distribution law and insulation structure optimization of the complex insulation structure under AC/DC mixed voltage. This paper studies E-field distribution law of multi-layer media under AC/DC mixed voltage, which has practical reference significance for the external insulation design of converter bushing, wall bushing and converter valve, and is of the great value for the actual DC power transmission and transformation project.
Study on the correction method of the influence of temperature factor in the simulation calculation of transformer bias current
Authors: Wang Ke , Sun Jiantao , Shen Hao , Zhao Wenbin
Published: March 2023

For analyzing the mechanism of single-polar earth operation of the HVDC transmission system arousing the DC bias of the transformer and correcting the influence of temperature factors on simulation, abstract grids were built. Based on the disciplinarian of ambient temperature affecting the DC resistivity of conductors and shallow soil, the mechanism of the ambient temperature taking effect on the DC bias current of the transformer was discussed. Applying the practical field measurement results, conclusions from the simulation and calculation were proved, and the method of classification correction was present. It was indicated that the modified calculation results of the transformer DC bias current would be closer to the actual measurement values.
Analysis of Regenerative Braking Strategy for Electric Vehicles Based on Braking Intention
Authors: Guo Bin , Zhang Hui
Published: March 2023

Improved energy recovery during braking is the goal of the distributed drive electric car regenerative braking system. A regenerative braking control strategy for electric vehicles based on braking intention is suggested in order to address various drivers’ braking intents and road adhesion circumstances. An electric vehicle regenerative braking model for distributed drives is created using the MATLAB/Simulink tools. On the basis of FTP-75 operating conditions and open road operating conditions, the efficacy and economy of the control strategy in this study are verified. According to the various road adhesion coefficients, the simulation results demonstrate that the control method in this work can appropriately divide the braking torque of the wheels on both sides of the coaxial wheel. The technique can successfully enhance the regenerative braking recovery of distributed drive electric vehicles as compared to the often employed regenerative braking control method.
Numerical Simulation of Centrifugal Pump Cavitation Based on ANSYS
Authors: Dong Jie , Li Wei
Published: March 2023

Centrifugal pump is the key equipment in petrochemical, agriculture, shipbuilding and other industries. Its safe, reliable and reliable work is an important guarantee to ensure its normal operation. Cavitation is a kind of unsteady compressible turbulent flow, which has a great influence on its performance and efficiency due to material exchange between gas and liquid phases. The appearance of the impeller internal cavitation phenomenon will reduce the pump head and efficiency, which is caused by the impeller and other flow components of damage, causing greater noise, and thereby the pump work and work performance have been greatly affected. Improving the efficiency of the centrifugal pump will undoubtedly reduce the social requirements for energy, which is consistent with the current goal of energy conservation and emission reduction advocated by society. The performance and efficiency of a centrifugal pump can be improved effectively by numerical simulation and analysis of the cavitation phenomenon.
Modeling and Control of Quadcopter Based on Sliding Mode Robust Control in the Wind Field
Authors: Lv Yulong , Shi Yongkang
Published: March 2023

Due to the low flying height, quadrotors are easily affected by external wind disturbances. In this paper, the dynamic model of the quadrotor flying in the wind field is established according to the Newton-Euler equation. The model introduces a weight function due to the phenomenon that different rotors are affected differently by the wind field due to their different positions relative to the wind field, and a sliding mode robust controller based on inner and outer loops is designed. The verification of the control system is carried out by means of simulation in a Gazebo and actual flight experiments in the wind field. The dynamic of the system and the controller performance under the wind field are also tested. The results show that the designed controller has the performance of stable flight in the wind field environment.
Research on Optimization SVPWM Method of Nine-switch Inverter for Bearingless Motor Based on Reducing Switching Times
Authors: Li Jinhui , Qiu Zhijian
Published: March 2023

The traditional bearingless motor system controlled by two three-phase inverters has a high cost and volume. In this paper, the nine-switch converter is applied to the bearingless motor control system, which can control the torque winding and suspension winding of the bearingless motor at the same time to save three MOSFETs. This paper proposes a nine-switch inverter SVPWM method to reduce switching loss. This method is no longer limited to only considering the action sequence of voltage vectors but reduces the switching number from selecting voltage vectors. The optimal nine-switch inverter basic voltage vector selection principle is determined by comparing the switching times of each sector combination with different voltage vector combinations. Finally, the simulation results verify the effectiveness of this method.
Design of portable multi-channel isolated CNC-regulated power supply
Authors: Wang Kuantian , Li Peng , Luo Mengxia
Published: March 2023

In order to facilitate the testing needs of electronic engineers, a multi-channel isolation adjustable switching regulated power supply controlled by an STM32 single-chip microcomputer is designed [1]. The power supply is programmable and adjustable by a single-chip microcomputer, and the humanized display operation interface is combined with the high efficiency of switching the power supply. It can realize three channels of 30v2a isolated output, and realize one channel of 90v2a or 30v6a output through a relay automatic switching series-parallel combination, to maximize power density. The power supply has the characteristics of high integration, small volume, large power, large adjustable range, high precision, and high efficiency. It can be applied to the debugging and operation of most electronic equipment.
Automatic Identification of Integrated Circuits Based on YOLOv5
Authors: Luo Jinhui
Published: March 2023

For the requirements of automatic testing in the IC industry, an improved algorithm based on YOLOv5 is proposed to identify IC. Firstly, the feature enhancement of small targets is based on the structure of the feature pyramid (FPN) to improve the accuracy of small target detection. Secondly, the weight of the loss value of the wrong sample in the loss function is enhanced to improve the training efficiency of the model. Finally, through the verification of the dataset, the results show that the accuracy of target recognition of the improved model is improved to 99.8% compared with the existing model, which verifies the effectiveness of this method.
SOC Balancing Control Method for Cascaded Energy Storage System under Extreme Working Conditions
Authors: Li Yong-Qi , Ma Zhong-Dao , Chen Man , Tan Qi-Peng , Wang Wen-Jie
Published: March 2023

To solve the problem of an unbalanced state of charge (SOC) between the in-phase sub-modules of the cascaded H-bridge energy storage system, this paper proposed a method based on carrier phase-shifting pulse-width modulation. Different from the traditional in-phase balancing method which is achieved by adding components, by setting the parameter related to the SOC difference to adjust the amplitude of the modulation wave, the new method could solve the problem that the traditional method is not applicable under extreme SOC conditions. The new in-phase SOC balancing method could expand the scenario, and the feasibility of the method is verified by simulation.
Primary Frequency Regulation Strategy of PMSG-Based Wind Turbines Integrated Inertia Control
Authors: Ren Zhihong , Zhao Qianlin , Lu Dingwen , Yang Jianwei
Published: March 2023

Direct-drive permanent magnet synchronous wind turbine-generator (PMSG) generally operates in maximum power point tracking (MPPT) mode. PMSG cannot provide additional active power support when the grid frequency fluctuates.The gradual increase of wind power penetration leads to greater frequency regulation pressure, which brings hidden dangers to the power grid. This paper focuses on the grid connection of direct-drive PMSG, proposing a primary frequency regulation strategy integrated with inertia control. The proposed strategy controls the rotor kinetic energy to simulate inertia of synchronous units by adding the support power of the response frequency variation. It concludes with variable power tracking control and energy storage system control. Compared with the traditional strategy retains active power, this proposed strategy increases wind energy utilization. Adopting variable power tracking control combined with energy storage can overcome secondary frequency drop and reduce energy storage configuration capacity.
Dynamic simulation research of adaptive support mechanism of pipeline inspection robot based on ADAMS
Authors: Xiao Yihao , Wang Jirong , Yang Jiaqi , Li Jun
Published: March 2023

The drainage pipe contains plenty of toxic gases that are hazardous to the human body, and the narrow size of the drainage pipe makes manual inspection difficult, so it is necessary to use a robot to replace the manual inspection of the drainage pipe. For this purpose, this paper designs a pipe inspection robot that can smoothly realize the passage and inspection in the drainage pipe. With an adaptive support mechanism, the robot can move to the working position in the pipeline. The trajectory of the end of the support mechanism is planned, and the dynamics of the support mechanism are simulated by ADAMS to analyze the motor load to verify that it can cope with the complex environment of the drainage pipe.
Research on Induction Measurement of Operators Approaching Charged Bodies in Complex Operation Scenarios
Authors: Liu Lijie , Zhang Zhaoguang , Qi Chunfeng
Published: March 2023

Aiming at the uneven distribution of the electric field and the difficulty in achieving low false alarms for operators approaching charged bodies in the complex operating environment in the power system, a mask region convolutional neural network (MR-CNN) based complex operation scene recognizer is first constructed in this paper to perform image feature extraction, target box regression, and classification training. Secondly, a simulated annealing-based mirror-image charge method is proposed to calculate the electric field distribution characteristics. The simulated annealing algorithm is used to optimize the number of charges of the mirror-image charges method to minimize the weighted sum of the calculation error and the electric field strength calculation time. Finally, the feasibility and effectiveness of the proposed algorithm are verified through simulation experiments.
Research on Fault Diagnosis of Hoist Dangerous Load Based on DBN
Authors: Shi Fahui , Wang Zheng , Ma Chi
Published: March 2023

At present, hoisting accidents caused by dangerous loads such as overloading, incomplete unloading, conveyance jamming, and rope loosening still occur. Therefore, this paper proposes a fault diagnosis method for dangerous loads of hoists based on the Deep Belief Network (DBN). With the stator current of the hoisting motor as the signal source, the 31-dimensional eigenvalues of the stator current of the hoisting motor in the time, frequency, and time-frequency domains are taken as the input parameters of the deep belief network. The restricted Boltzmann machine is used for unsupervised pre-training through layer-by-layer transmission and layer-by-layer training. The BP neural network, as the top-level classifier, is used for supervised fine-tuning training to finally complete the whole training process of the depth belief network. Relying on the advantages of the depth belief network, which has fast training speed and strong feature extraction ability. It makes up for the deficiency of the traditional algorithm in feature extraction and classification separation, resulting in the loss of details, and finally realizes the overload Classification of four types of dangerous loads, i.e., unloaded, blocked, and slackened. The results show that the method based on DBN has higher identification and better diagnosis effect.
Design of a prediction model based on improved BP neural network and particle swarm optimization for more accurate budget of biogas production
Authors: Wu YuChen , Zhang GuangMing
Published: March 2023

In order to accurately predict the daily gas production of large and medium-sized biogas projects, the improved BP neural network algorithm was used, and the PSO algorithm was introduced to optimize the parameters. According to the anaerobic fermentation mechanism and the actual engineering operation status, a prediction model was established with temperature, daily feed volume, NH3, TS concentration and pH value as input layer nodes, and daily biogas production as output layer nodes. The 116 sets of data obtained by remote data acquisition are used as training samples and test samples of the model, and the simulation is carried out by Matlab software. The results show that the PSO-LM-BP neural network has good predictive ability for the daily gas production of biogas. The established biogas daily gas production prediction model not only converges fast but also has high accuracy.