bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterizing and tuning exceptional points using Newton polygons
Authors: Jaiswal Rimika , Banerjee Ayan , Narayan Awadhesh
Published: March 2023

The study of non-Hermitian degeneracies—called exceptional points (EPs)—has become an exciting frontier at the crossroads of optics, photonics, acoustics, and quantum physics. Here, we introduce the Newton polygon method as a general algebraic framework for characterizing and tuning EPs. Newton polygons, first described by Isaac Newton, are conventionally used in algebraic geometry, with deep roots in various topics in modern mathematics. We propose and illustrate how the Newton polygon method can enable the prediction of higher-order EPs, using a recently experimentally realized optical system. Using the paradigmatic Hatano-Nelson model, we demonstrate how our method can predict the presence of the non-Hermitian skin effect. As further application of our framework, we show the presence of tunable EPs of various orders in PT-symmetric one-dimensional models. We further extend our method to study EPs in higher number of variables and demonstrate that it can reveal rich anisotropic behaviour around such degeneracies. Our work provides an analytic recipe to understand exceptional physics.
Spiraling elliptic hollow beams with cross phase
Authors: Liang Guo , Shu Fangjie , Ma Shaoshuo , Cheng Wenjing , Sun Chunzhi
Published: March 2023

We introduced a class of spiraling elliptic hollow beams with the cross phase. Due to the cross phase, the spiraling elliptic hollow beams exhibit three key characteristics, having the elliptic peak ring, carrying the orbital angular momentum (OAM), and performing rotations. We investigated both linear and nonlinear evolutions of the spiraling elliptic hollow beams, and found they can propagate stably, thanks to the cross phase. Especially, we obtained the breather states of spiraling elliptic hollow beams in nonlocally nonlinear medium, and could handily control the rotation by changing optical powers. We discussed both the OAM property and optical force property. By using the spiraling elliptic hollow beams, we can achieve a jointly multiple manipulation on particles at the same time. In one step, we can trap and simultaneously rotate the particles.
Thermally induced all-optical ferromagnetic resonance in thin YIG films
Authors: Schmoranzerová Eva , Kimák Jozef , Schlitz Richard , Goennenwein Sebastian T B , Kriegner Dominik , Reichlová Helena , Šobáň Zbyněk , Jakob Gerhard , Guo Er-Jia , Kläui Mathias , Münzenberg Markus , Němec Petr , Ostatnický Tomáš
Published: March 2023

All-optical ferromagnetic resonance (AO-FMR) is a powerful tool for the local detection of micromagnetic parameters, such as magnetic anisotropy, Gilbert damping or spin stiffness. In this work we demonstrate that the AO-FMR method can be used in thin films of yttrium iron garnet (YIG) if a metallic capping layer (Au, Pt) is deposited on top of the film. Magnetization precession is triggered by heating of the metallic layer with femtosecond laser pulses. The heat pulse modifies the magneto-crystalline anisotropy of the YIG film and shifts the quasi-equilibrium orientation of the magnetization, which results in precessional magnetization dynamics. The laser-induced magnetization precession corresponds to a uniform (Kittel) magnon mode, with the precession frequency determined by the magnetic anisotropy of the material as well as the external magnetic field, and the damping time set by a Gilbert damping parameter. The AO-FMR method thus enables measuring local magnetic properties, with a resolution given by the laser spot size.
Density of states effects on emission and scattering of photons in plasmas
Authors: Gaponenko Sergey V , Novitsky Denis V , Guzatov Dmitry V
Published: March 2023

Plasma supports electromagnetic waves propagation for frequencies higher than plasma frequency but features dielectric permittivity less than 1. This property leads to photon density of states (DOS) lower than in vacuum and should result in subnatural spectral linewidths, sub-Planckian spectrum of thermal radiation, and sub-Rayleigh scattering as well as in lower inelastic photon scattering including Raman scattering. Lamb shift will be altered as well though the decisive contribution from high-energy modes in this case makes the photon DOS effect rather small since plasma DOS converges with the vacuum one in the limit of infinite frequencies. We emphasize the basic character of all these phenomena though absolute values of corrections in many real experiments may appear to be small as compared to other factors. We found that dissipative losses make possible DOS effects smaller though not vanishing and additionally bring about indefinite growth of DOS in the low-frequency limit.
A variationally improved Hulburt-Hirschfelder analytical potential energy function for diatomic molecules
Authors: Tian Hongrui , Fan Qunchao , Fan Zhixiang , Li Huidong , Fu Jia , Ma Jie , Xie Feng
Published: March 2023

In this paper, a variationally improved Hulburt-Hirschfelder (VIHH) analytical potential energy function (APEF) is presented and tested. The VIHH potential is composed of the remedy function

Λ

r

and the improved Hulburt-Hirschfelder (IHH) APEF which possesses the same explicit parameters (

D

e

,

ω

e

,

ω

e

x

e

,

B

e

,

α

e

,

r

e

) with VIHH potential. Potential energy curves (PECs) for the ground electronic states of HI, HBr and KLi molecules have been modeled by the VIHH analytical potential, and it suggests that the VIHH potential is in good agreement of Rydberg-Klein-Rees (RKR) potential points and is superior to the original Hulburt-Hirschfelder (HH) potential, IHH potential and Morse potential, especially in the dissociation and the long-range region. The vibrational energy levels for the ground electronic state of the HI, HBr, and KLi molecules are obtained by numerically solving the radial Schrödinger equation using the LEVEL program for the case of the Morse potential, HH potential, IHH potential and the VIHH potential functions. The comparison for both vibrational energy levels and VIHH potential functions shows better agreement with the experimental data than the other potential functions. Comparing with IHH potential, the VIHH potential which included the remedy function

Λ

r

has better physical behavior in the long-range region and the

Λ

r

is effective for vanishing the invalid barrier.
Comparison of different noble gas injections by massive gas injection on plasma disruption mitigation on Experimental Advanced Superconducting Tokamak
Authors: Zhao Sheng-Bo , Zhuang Hui-Dong , Yuan Jing-Sheng , Zhang De-Hao , Li Li , Zeng Long , Chen Da-Long , Mao Song-Tao , Huang Ming , Zuo Gui-Zhong , Hu Jian-Sheng
Published: March 2023

Massive gas injection (MGI) is a traditional plasma disruption mitigation method. This method directly injected massive gas into the pre-disruption plasma and had been developed on the Experimental Advanced Superconducting Tokamak (EAST). Different noble gas injection experiments, including He, Ne, and Ar, were performed to compare the mitigation effect of plasma disruption by evaluating the key parameters such as flight time, pre-thermal quench (pre-TQ), and current quench (CQ). The flight time was shorter for low atomic number (Z) gas, and the decrease in flight time by increasing the amount of gas was insignificant. However, both pre-TQ and CQ durations decreased considerably with the increase in gas injection amount. The effect of atomic mass on pre-TQ and CQ durations showed the opposite trend. The observed trend could help in controlling CQ duration in a reasonable area. Moreover, the analysis of radiation distribution with different impurity injections indicated that low Z impurity could reduce the asymmetry of radiation, which is valuable in mitigating plasma disruption. These results provided essential data support for plasma disruption mitigation on EAST and future fusion devices.
Drift surface solver for runaway electron current dominant equilibria during the current quench
Authors: Yuan Lu , Hu Di
Published: March 2023

Runaway electron current generated during the current quench phase of tokamak disruptions could result in severe damage to future high performance devices. To control and mitigate such runaway electron current, it is important to accurately describe the runaway electron current dominated equilibrium, based on which further stability analysis could be carried out. In this paper, we derive a Grad–Shafranov-like equation solving for the axisymmetric drift surfaces of the runaway electrons instead of the magnetic flux surfaces for the simple case that all runaway electrons share the same parallel momentum. This new equilibrium equation is then numerically solved with simple rectangular wall with ITER-like and MAST-like geometry parameters. The deviation between the drift surfaces and the flux surfaces is readily obtained, and runaway electrons are found to be well confined even in regions with open field lines. The change of the runaway electron parallel momentum is found to result in a horizontal current center displacement without any changes in the total current or the external field. The runaway current density profile is found to affect the susceptibility of such displacement, with flatter profiles result in more displacement by the same momentum change. With up–down asymmetry in the external poloidal field, such displacement is accompanied by a vertical displacement of runaway electron current. It is found that this effect is more pronounced in smaller, compact device and weaker poloidal field cases. The above results demonstrate the dynamics of current center displacement caused by the momentum space change in the runaway electrons, and pave a way for more sophisticated runaway current equilibrium theory in the future with more realistic consideration on the runaway electron momentum distribution. This new equilibrium theory also provides foundation for future stability analysis of the runaway electron current.
Revisiting D-meson twist-2, 3 distribution amplitudes*
Authors: Zhong Tao , Huang Dong , Fu Hai-Bing
Published: March 2023

Owing to the significant difference between the experimental measurements and the theoretical predictions of the standard model (SM) for the value of

of the semileptonic decay

, researchers speculate that this decay may be evidence of new physics beyond the SM. Usually, the D-meson twist-2, 3 distribution amplitudes (DAs)

,

, and

are the main error sources when perturbative QCD factorization and light-cone QCD sum rules are used to study

. Therefore, it is important to obtain more reasonable and accurate behaviors for these DAs. Motivated by our previous work [Phys. Rev. D 104, no.1, 016021 (2021)] on pionic leading-twist DA, we revisit D-meson twist-2, 3 DAs

,

, and

. New sum rule formulae for the

-moments of these three DAs are suggested for obtaining more accurate values. The light-cone harmonic oscillator models for the DAs are improved, and their parameters are determined by fitting the values of ξ
-moments via the least squares method.
One-loop formulas for H → Zν

l

ν

l
for l = e, µ, τ in 't Hooft-Veltman gauge*
Authors: Tran Dzung Tri , Phan Khiem Hong
Published: March 2023

In this paper, we present analytical results for one-loop contributions to the decay processes

(for

). The calculations are performed within the Standard Model framework in the 't Hooft-Veltman gauge. One-loop form factors are then written in terms of scalar one-loop functions in the standard notations of

. As a result, one-loop decay rates for the decay channels can be evaluated numerically by using the package. Furthermore, we analyze the signals of

via the production processes

, including the initial beam polarizations at future lepton colliders. The Standard Model backgrounds, such as the processes

, are also examined in this study. Numerical results indicate that one-loop corrections make contributions of approximately 10% to the decay rates. These are sizeable contributions and should be taken into account at future colliders. We show that the signals

are clearly visible at the center-of-mass energy

GeV and are difficult to probe in higher-energy regions owing to the dominant backgrounds.
How to entrain a selected neuronal rhythm but not others: open-loop dithered brain stimulation for selective entrainment
Authors: Duchet Benoit , Sermon James J , Weerasinghe Gihan , Denison Timothy , Bogacz Rafal
Published: March 2023

Objective. While brain stimulation therapies such as deep brain stimulation for Parkinson’s disease (PD) can be effective, they have yet to reach their full potential across neurological disorders. Entraining neuronal rhythms using rhythmic brain stimulation has been suggested as a new therapeutic mechanism to restore neurotypical behaviour in conditions such as chronic pain, depression, and Alzheimer’s disease. However, theoretical and experimental evidence indicate that brain stimulation can also entrain neuronal rhythms at sub- and super-harmonics, far from the stimulation frequency. Crucially, these counterintuitive effects could be harmful to patients, for example by triggering debilitating involuntary movements in PD. We therefore seek a principled approach to selectively promote rhythms close to the stimulation frequency, while avoiding potential harmful effects by preventing entrainment at sub- and super-harmonics. Approach. Our open-loop approach to selective entrainment, dithered stimulation, consists in adding white noise to the stimulation period. Main results. We theoretically establish the ability of dithered stimulation to selectively entrain a given brain rhythm, and verify its efficacy in simulations of uncoupled neural oscillators, and networks of coupled neural oscillators. Furthermore, we show that dithered stimulation can be implemented in neurostimulators with limited capabilities by toggling within a finite set of stimulation frequencies. Significance. Likely implementable across a variety of existing brain stimulation devices, dithering-based selective entrainment has potential to enable new brain stimulation therapies, as well as new neuroscientific research exploiting its ability to modulate higher-order entrainment.
Optical sensor response towards hydrogen peroxide in low fat and full cream milk
Authors: Taib N A M , Shazlan S N M , Adnan N N , Emran N E
Published: March 2023

Fiber Optic Displacement Sensor (FODS) categorized as one of the optical sensor based reflective intensity modulation. An intensity based sensor have been widely used in detecting various substances due to their simplicity structures. Generally for sensing principle, a pair of fiber is used to construct FODS which one of optical fiber is the transmitting fiber and another one is receiving fiber. The objective of this current work is to introduce FODS to evaluate the optical response in terms of voltage reading at different concentration of hydrogen peroxide in two different types of milk. A real-time measurement, low cost, stability, high sensitivity and simplicity of design promote a well-developed sensor in providing useful parameters in detecting hydrogen peroxide in milk. Hydrogen peroxide is an adulterated agent added in milk that can harm the consumers. Transmitive optical sensor as a function of displacement technique was developed to study the hydrogen peroxide concentrations in the range of 0 %-10 % as consuming more than 3-10 % of hydrogen peroxide can cause mild allergies reactions, stomach upset and vomiting. The output from the receiving fiber in this designated system was measured in terms of voltage reading through multimeter. The sensor shows outstanding performances of delivering 0.0007 V/% sensitivity for low fat milk and with linearity of >98 %. Whereas, the sensitivity achieved for full cream milk was 0.0005 V/% with a good linearity >97 %. The simplicity and credibility of this system offer a good opportunity in this project and also foods industry applications.
Synthesis of nickel nanoparticles by pulsed laser ablation in different liquid media
Authors: Yahaya Nurul Izmaliza Syakila Binti , Sapian Nur Izzati Husna Binti , Duralim Maisarah Binti , Aziz Muhammad Safwan Bin Abd , Rahman  , Alias Siti Salwa binti , Husein Nor Ain Binti
Published: March 2023

Nickel nanoparticles exhibit superior ferromagnetic properties. This has attracted great interest due to its significant potential applications in various fields. The properties of nanomaterials are greatly affected by the environmental conditions during the synthetization process. In this work, nickel nanoparticles were synthesized by pulsed laser ablation in distilled water, ethylene glycol, chitosan, gum Arabic and walnut oil. For all samples, the ablated process was conducted for 5 minutes. The optical properties of colloidal nanoparticles were investigated by UV-Visible spectroscopy and Fourier Transform Infrared (FT-IR) spectrometer. Data from experimental works released that walnut oil has highest absorbance intensity which might be contributed to the existence of alkene functional group.
The catalytic efficiency of Ru/Mn/Ce-Al2O3 in the reduction of HCN in dry methane reforming with CO2 assisted by non-thermal plasma
Authors: Kok David Hong Kian , Ibrahim Raja Kamarulzaman Raja , Toemen Susilawati , Bakar Mohd Bakri
Published: March 2023

This study investigates the catalytic activity of Ru/Mn/Ce-Al2O3 in eliminating HCN via dry reforming CH4 with CO2 in the packed-bed dielectric barrier discharge non-thermal plasma (DBD NTP). A packed bed DBD configuration method was carried out in the non-thermal plasma with Ru/Mn/Ce-Al2O3 catalyst, whereby BaTiO3 beads was the dielectric medium. The carrier gas for dry methane reforming was N2, the peak-to-peak voltage was 24 kV and the total flow rate was 100 sccm with a ratio of 5:5:90 (CH4:CO2:N2), respectively. Gaseous products and by-products were analysed by Fourier transform infra-red (FTIR) spectroscopy. Experimental results revealed that Ru/Mn/Ce-Al2O3 catalyst could eliminate HCN at approximately 82% and had a low selectivity in decomposing NH3. Besides, the conversion of CH4 achieved was approximately 68%.
Connecting b → sℓℓ with

b→sνν¯

and

s→dνν¯
Authors: Novoa-Brunet Martín
Published: March 2023

We discuss the consequences of deviations from the Standard Model observed in b → sμ
+
μ
− transitions for flavour-changing neutral-current processes involving down-type quarks and neutrinos. We work within an effective field theory approach respecting the SM gauge symmetry, including right-handed currents, a flavour structure based on approximate U(2) symmetry, and assuming only SM-like light neutrinos. We discuss correlations among

B
→

h
s

ν

ν
¯

(hs
= K, K*, Xs
),

K
+

→

π
+

ν

ν
¯

and

K
L

→

π
0

ν

ν
¯

branching ratios in the case of linear Minimal Flavour Violation and in a more general framework.
Lattice predictions and comparison with experimental data for the radiative kaon decays

K+→ℓ+νℓγ

and

K+→ℓ+νℓℓ′+ℓ′−
Authors: Mazzetti F
Published: March 2023

K
+

→

ℓ
+

ν
ℓ

γ

and

K
+

→

ℓ
+

ν
ℓ

ℓ

′
+

ℓ

′
−

decays are characterized by the emission from the kaon of either a real or virtual photon, respectively. The nonperturbative interaction of the photon with the internal hadronic structure of the decaying meson is described by suitable form factors. With the huge improvement in the precision of lattice QCD results, increasingly QED corrections are included and in this work we review the latest lattice QCD predictions for the form factors and/or branching ratios of those processes. Moreover, we compare those predictions with existing experimental results. The comparison provides some interesting puzzles suggesting possible signs of new physics and motivates future improvements on both the theoretical and experimental determinations of the relevant form factors.
Measurement of the radiative decay K
+ → π
0
e
+
vγ at the NA62 experiment
Authors: Piccini Mauro
Published: March 2023

The NA62 experiment at CERN reports results from a study of radiative kaon decay K
+ → π
0
e
+
vγ, using a data sample recorded in the years 2017 and 2018. The sample comprises O(100k) candidates with sub-percent background contamination. Preliminary results of the most precise measurement of the corresponding branching ratio and with the measurement of the T-asymmetry parameter are presented.
Rare decays at LHCb
Authors: Santimaria Marco
Published: March 2023

Flavour-changing neutral-current processes, such as b → sℓ
+
ℓ
−, are forbidden at tree level in the Standard Model and hence might receive comparatively large corrections from new particles. This proceeding paper highlights recent measurements from LHCb on b → sℓ
+
ℓ
− and purely-leptonic decays, including tests of lepton flavour universality and searches for lepton flavour violation.
Neutrino Physics
Authors: Sakashita Ken
Published: March 2023

The observation of neutrino oscillations is firm evidence of non-zero neutrino mass. Neutrino mass and mixing have been studied by neutrino oscillation experiments so far. One of the remaining questions is whether neutrinos violate CP symmetry. Exploring new CP violation is also a subject of kaon physics. There are other common physics topics between neutrino and kaon experiments. In this talk, recent progress and future prospects of neutrino experiments for topics related to kaon physics will be discussed.
Searches for the light invisible hypothetic pseudoscalar in K
+ → π
+
π
0
P decay
Authors: Sadovsky Alexander
Published: March 2023

A high statistics data sample of the K
+ decays was recorded in 2012 and 2013 by the OKA collaboration. The missing mass analysis was performed to search for the light invisible pseudoscalar P in the decay K
+ → π
+
π
0
P for two alternative scenarios, namely for the pseudoscalar sgoldstino and for the axion. No signal is observed, the upper limits for the branching ratio of the decay are derived for both scenarios. The 90% CL upper limit for the case of sgoldstino is estimated to be in the region from 2 · 10−5 to 1 · 10−6 for the sgoldsino mass from 20 to 200 MeV and for the case of axion the upper limit is changing from 1 · 10−5 to 1 · 10−6 for the same mass range.
First results for searches of exotic decays with NA62 in beam dump mode
Authors: Spadaro Tommaso
Published: March 2023

We report the results of a search for dark photon in-flight decays to μ
+
μ
− pairs at NA62. Dark photons could be produced by dumping protons onto a copper-iron absorber, reach the NA62 decay volume more than 80 m downstream of the dump and decay therein. The measurement is based on data collected in 2021 which correspond to 1.4 × 1017 dumped protons.
K → μ+μ−
as a third kaon golden mode
Authors: Dery Avital
Published: March 2023

Recent progress has demonstrated that the K → μ
+
μ
− decay carries clean short-distance information, attainable from a measurement of time-dependence sensitive to KL
− KS
interference effects. We review the ingredients that go into this proposed extraction, and discuss the sensitivity to the CKM parameter

η
¯

as well as to various NP scenarios.
First thought on a high-intensity KS
experiment
Authors: Marchevski Radoslav
Published: March 2023

The K → µµ decays have recently been identified as another golden kaon physics mode along-side the rare

K
→
π
ν

ν
¯

processes. These golden modes provide precision tests of the Standard Model with very high sensitivity to New Physics. The presented study is exploring the possibility to address the KL
− KS
→ μ
+
μ
− interference experimentally and outlines the challenges associated with such an ambitious project for the far future. A next-generation experiment at the intensity frontier is required that should be capable of collecting a large sample of 𝒪(1014 − 1015 ) KL
and KS
decays. Challenges related to the beamline design and detector technology need to be overcome if we want to address this mode experimentally. A significant background suppression of KS
→ π
+
π
− and radiative KL
→ μ
+
μ
−
γ decays is imperative for a few % measurement, which would require excellent kinematic resolution and efficient photon detection. The first attempt at a possible experimental setup to measure this effect is presented. Last but not least, a huge number of neutral particles produced offers the possibility to study a plethora of other rare KL
, KS
decays as well as hyperon decays enhancing the physics motivation for such an initiative.
Measurement of muon spin relaxation time in various scintillating materials
Authors: Horie Keito , Mihara Mototsugu , Shimizu Suguru , Kamada Kei
Published: March 2023

A new experimental method to search for T-violating transverse muon polarization (PT
) in the K+
→ π
0
μ
+
ν decay was recently proposed. In this new experiment, the measurements of the μ
+ momentum vector, the π
0 momentum vector, and the μ
+ polarization will be performed by the same segmented calorimeter. One of key issues is the choice of a scintillation material which can maintain the μ
+ spin polarization for several μ
+ lifetimes. A test experiment to measure the μ
+ spin relaxation time in various scintillating materials was carried out at J-PARC Material and Life Science Facility (MLF). It was concluded that the residual μ
+ polarization in CeF3 is high enough to perform the proposed T-violation experiment.
A three-dimensional sampling electromagnetic calorimeter for the KOTO II experiment with the future extension of J-PARC Hadron Facility
Authors: Kim YoungJun
Published: March 2023

We present a Geant4-based simulation study of the three-dimensional (3D) electromagnetic sampling calorimeter (ECAL). The 3D ECAL model consists of alternating layers of plastic scintillator and lead sheets where the scintillators are divided into strips and alternatively oriented in vertical and horizontal directions. With the energy deposits in the individual strips as a result of Geant4 simulation, the incidence angle of photons is reconstructed using the XGBoost with boosted decision trees. We report on the performance of the directional measurement which depends on both detector configuration and the maturity of the training.
Reduction of charged kaon background in the KOTO experiment
Authors: Shiraishi R
Published: March 2023

The KOTO experiment at J-PARC searches for the rare kaon decay

K
L

→

π
0

ν

ν
¯

. In the analysis of the data collected from 2016 to 2018, the largest background was caused by decays of K
±. To detect K
± in the beam line, we developed an in-beam charged particle detector in 2020. After installing it in the KOTO detector system, we collected physics data in 2021. Using a control sample of K
± events, we estimated the inefficiency to be

8.0

−
3.0

+
1.1

%

, which reduces the K
± background by a factor of 13. The number of K
± background events was suppressed to be

0.043

−
0.022

+
0.016

at the single event sensitivity of 7.9 × 10−10.
Analysis Techniques for Neutron Background Suppression at KOTO
Authors: Tung Yu-Chen
Published: March 2023

We present two analysis techniques based on novel machine learning and classic Fourier frequency analysis that suppress the neutron background in the

K
L
0

→

π
0

ν

ν
¯

search at the J-PARC KOTO experiment by 𝒪(10−6).
Research on Metal Target Classification Method Based on Multi-Frequency Electromagnetic Induction
Authors: Wang Zhan , Jiang HeJun , Luo ZhaoPeng , Zheng FangFu , Xiao KeZhen , Qu ShiHua , Wu MeiWu
Published: March 2023

The traditional single-frequency metal mine detector is limited by the single-frequency component, which is difficult to meet the requirements of high-accuracy detection of multiple types of mine targets. The modulation square wave is used to transmit the multi-frequency signal based on the multi-frequency electromagnetic induction technology. The phase-locked amplifier is used to extract the signal feature of each frequency component. The naive bayesian algorithm is used to classify metal targets according to the extracted feature vectors. This method can effectively improve target classification accuracy compared with single-frequency metal mine detectors.
Infrared small target detection based on YOLO v4
Authors: Lin Zhongwu , Huang Min , Zhou Qinghui
Published: March 2023

Infrared imaging is highly stealthy, reconnaissance and resistant to interference and currently has numerous practical applications in many fields, particularly in the military and civilian sectors. Infrared images are prone to drowning small targets in the background due to the lack of textural detail and the presence of a large amount of background noise. Small target detection on infrared images is therefore very challenging, and traditional model-driven algorithms are no longer very applicable in the face of complex and variable infrared images, so more and more people are turning to deep learning methods. We have designed a target detection network based on YOLO v4 with the following improvements, using GhostNet as the backbone network used to extract features and achieving a lighter weighting of the backbone network. We added a coordinate attention mechanism to the design of the feature aggregation process of the network, so that the network senses the spatial location relationship while the channel is attended to, enhancing the network’s ability to localise targets. To further reduce the number of network parameters, by using depthwise separable convolution in the feature aggregation part and detection part instead of normal convolution. Our experimental comparisons on the dataset NUAA-SISRT show that Ghost-CA-YOLO v4 is the leader in terms of detection accuracy and parameter efficiency. The model has an mAP metric of 73.31% and an F1 value of 0.78. The number of parameters is 44.8M, which is 1/5 of that of YOLO v4.
Electrostatic potential simulation and safety countermeasures in the tank of hazardous chemicals tanker
Authors: Liu Jianli , Jin Xin , Han Xuefeng
Published: March 2023

In this paper, taking a benzene transport vehicle as an example, a cylindrical tank model is established according to the relevant standards, and the electrostatic potential distribution in the tank of dangerous chemicals is numerically simulated. The potential distribution in the tank is calculated by numerical calculation software, and the three-dimensional distribution map of the electrostatic potential of the medium in the tank is obtained. The general rules between the electrostatic potential distribution in the tank of a hazardous chemical tanker and the filling rate, the number of Anti-wave plates, and the two phases of gas and liquid were analyzed. The relationship between volume, Anti-wave plate area, and electrostatic potential was further analyzed by studying the relationship between electrostatic potential and medium parameters. A model of an elliptical cylindrical tank was also constructed, and corresponding anti-static measures were proposed.
OpenCV-based SF6 density controller dial pointer angle recognition
Authors: Yu Zhangsi , Ning Zhang , Yang Houcheng
Published: March 2023

To solve the problems of the low efficiency and poor accuracy of the manual detection in the factory inspection of the SF6 density controller, this paper proposes an SF6 density controller dial pointer angle identification method. First, the image of the dial pointer at a specific position is acquired according to the working characteristics of the SF6 density controller. The center and radius of the contour circle inside the scale line in the dial are extracted using the Hoff gradient method and the image is coordinate transformed using this parameter. Then the coordinate-transformed image is pre-processed. And finally, the threshold of the image after pre-processing is traversed and the length is used to characterize the pointer angle through the correspondence between the scale line and the angle. The angle of the pointer is characterized by the correspondence between the scale and the angle using the length. This paper uses Python and OpenCV vision library to complete the algorithm and through experiments, the algorithm can achieve high precision pointer angle recognition.
A method for simultaneously calibrating projectors and correcting nonlinearities
Authors: Huang Geng , Lv CiXing
Published: March 2023

In FPP, projector nonlinearity is a significant factor affecting calibration accuracy and the reconstruction effect. Existing techniques frequently separate system calibration from nonlinearity correction, and the majority of these correction techniques necessitate the acquisition of additional images, making the process laborious. In this study, we provide a technique for solving both the nonlinear error function and the projector parameters at the same time. The parameters of the nonlinear error function are first estimated using a theoretical calculation of the phase error due to nonlinearity, based on the distribution relationship between the reprojection error and the phase of the characteristic points. The resulting nonlinear error function is then used to correct for the wrapped phase. It was shown that the projector reprojection error was decreased by 14.7 percent (RMS) and the object reconstruction quality was enhanced after two iterations.
Improvement in Connecting the Structure of Spherical Crown Middle Head
Authors: Luo Yu , Wang Zhuobin , Wang Qiang , Mao Haofei , Hong Qingbin , Li Liang
Published: March 2023

In a pressure vessel, a spherical crown head can be used as an end head or a middle head. Without a common tangent to connect the surfaces of the spherical shell and cylindrical shell, the connection between the spherical crown head and shell produces stresses and deformation at the edge of the connection, so the head and shell in use need to be stiffened and a stiffening section needs to be arranged. With a stiffening section, stainless steel equipment includes more welding beads and looks less aesthetically attractive. If the shell is stiffened as a whole, the thickness of the shell needs to be increased to the thickness of the stiffening section, which is closely related to the radius of curvature Ri of the spherical crown head. Therefore, in design, the optimization of the ratio of the radius of curvature of the head to the internal diameter Di of the shell must be considered, to obtain the spherical crown head and stiffening section with the minimum thickness. However, in most cases, the thickness obtained may not be the most economical, because the head may be non-standard, and is usually formed by stamping, requiring a costly die. Furthermore, it is permissible for all thicknesses of the shell to be increased to obtain the entire shell instead of a pieced-together shell, and such design can cause too great an allowance of strength, merely increasing the costs of manufacturing. The design of dual-cavity-tank equipment used for irrigation by a company requires the use of a spherical crown head as the middle head. In the design, the challenge confronted by the authors is to ensure an attractive appearance, as well as an economical and reasonable cost. In the design, the internal volume was slightly reduced, the way of connecting the shell and the stiffening section was changed, and the optimal ratio of the radius of curvature of the head to the internal diameter of the shell was selected, to obtain the most reasonable thicknesses of spherical crown head and stiffening section. Thus, the actual difficulties encountered have been resolved.
LSTM multivariate time series-based prediction of grassland multi-indicator data
Authors: Qu Jiahao , Wang Hui , Zhang Ying
Published: March 2023

Xilinguole grassland in Inner Mongolia is one of the four major grasslands in China, which not only provides a large amount of livestock industry for the country but also prevents soil erosion and plays a key role in the regulation of ecological climate. To ensure the sustainable development of grasslands, this paper provides prediction data for the grassland grazing system optimization model by using LSTM multivariate time series prediction method to predict soil moisture, chemical properties, and desertification degree of grasslands under different grazing strategies to ensure the sustainable development of grasslands.
Design of the 3D Printer Nozzle Cleaning System
Authors: Wu Yuan , Wang Hui , Zheng Zehua , Li Xingzhen
Published: March 2023

Aiming at the problems of low cleaning efficiency, damaged nozzle, and high safety hazard in the traditional cleaning method of the fused deposition modeling (FDM) equipment nozzle, an environmentally friendly nozzle cleaning system was designed by using the chemical solvent and ultrasonic cleaning technology. The modular design of the nozzle clamping module can improve the nozzle loading efficiency and cleaning efficiency. The cleaning liquid circulation device makes the cleaning process automated under the coordination of the control module, which effectively reduces the safety hazards of the cleaning process. A thermal drying device is mainly used to speed up the drying rate of the nozzle. An exhaust gas purification device is used to absorb the volatile chemicals in the cleaning process and reduce pollution in the working environment.
Research on digital twin technology of large-scale offshore wind power flexible direct transmission system
Authors: Wang Ye , Xu Kai , Du Yunlong , Ren Xuchao , Wang Chenqing
Published: March 2023

With the rapid development of wind power technology, offshore wind power transmission technology has gradually matured. Combined with the first large-scale offshore wind power flexible DC transmission system in China, this paper builds a digital twin system that is close to the actual system. The article first introduces the origin and definition of digital win technology and gives the five-dimensional model of the digital twin. Then, it focuses on the technical realization of the offshore wind power digital twin system, including the five-dimensional model of the offshore wind power digital twin system. The key technologies in the advanced application of the twin system - real-time simulation technology and 3D holographic visual display technology are introduced, and their effects are shown. The realization of the digital twin technology of the large-scale offshore wind power flexible DC transmission system provides more valuable information for the operation, management, scheduling, and decision-making of the offshore wind power flexible direct transmission system.
Design and Simulation of Autom0atic Feeding and Unloading System for Finishing RV Reducer Planetary Carrier
Authors: Zhang Hongxia , Tian Zhicheng , Fei Lilin
Published: March 2023

To realize the unmanned production of precision planetary cycloidal reducer planetary frame finishing, the design of this paper focuses on the robot loading and unloading system for RV reducer planetary frame finishing, and the structural dimensions of the end robot of the system are calculated in detail. The load-bearing parts of the truss affect the strength and stiffness of the whole truss system, and the ANSYS Workbench software is used to perform the static finite element analysis of the truss. The simulation results show that the maximum total deformation of the joist beam is about 0.403mm, which can effectively meet the overall loading and unloading accuracy requirements. The maximum local stress value of the joist is 5.5 MPa, the yield stress of Q235 is 235 MPa, the tensile strength is 375-460 Mpa, which meets the strength requirement, and the automatic loading and unloading system of the joist is determined to meet the design requirements.
Stability analysis of an angle trimmer mechanism applied to a double crystal monochromator
Authors: Jiang Bo , Zhang Zijie , Zhou Shun , Chu Yuanbo , Guo Yifan
Published: March 2023

Double crystal monochromator is the core device of the synchrotron light source beamline, for the application of double crystal monochromator trimmer mechanism not only needs a high angular adjustment resolution, but also needs a high inherent frequency to ensure its stability. In this paper, we have analyzed the inherent frequency of an angle-trimming mechanism applied to a biocrystal monochromator by the energy method, established the relationship equation between its inherent frequency and each parameter of the mechanism, and analyzed the influence of each parameter on its inherent frequency. And we establish the simulation model according to the actual installation situation to carry out finite element analysis. The results prove that the mechanism has excellent stability performance and meets the requirements of light source use.
Design of Brush Plating Repair Device for Big Hole of Connecting Rod of Automobile
Authors: Qiu Peng , Li Wei
Published: March 2023

Brush plating technology has been applied to the surface repair and strengthening of parts and achieved remarkable benefits, so it can be used as a part remanufacturing method. This graduation project aims to design a brush plating repair device for the big end hole of an automobile connecting rod in the field of automobile technology application, including brush plating power supply, electroplating pen, plating solution, and brush plating auxiliary equipment, so as to realize the clamping and rotation of the workpiece, the clamping of plating pen and the axial and radial movement of plating pen relative to the workpiece. The three-dimensional models of parts and parts are established by modeling software and installed. The equipment can greatly improve the maintenance efficiency and product quality of vehicle connecting rods, obtain a safer production process, and is suitable for mass reproduction of vehicle connecting rods.
Design of dynamic gripping control system for robotic arm based on the NJ motion controller
Authors: Pei Haijian , Zhang Yi
Published: March 2023

Due to the increasing improvement of people’s material living conditions, the requirements and needs for mechanical products are rising, thus indirectly promoting the development of mechanical devices. The study aims to provide an in-depth discussion on the power capture of NJ-type robots, the working principle, and arithmetic methods of NJ-type controllers, and to conduct simulation tests of NJ-type robots. The experiments showed that 99.775% of the test data were distributed between 30 ms and 50 ms, and the actual rotational speed was only about 250 ms. The missed and wrong capture rates were 3.58% and 0%, respectively, which indicated that the actual rotational speed was almost the same as the specified one. The results show that the manipulator designed with the NJ-based motion controller achieves a high level of accuracy and stability, and can achieve accurate grasping, which provides convenient conditions for people to perform self-service table tennis entertainment in their daily lives.
Inverse kinematics analysis of rock drilling manipulator based on improved SA-PSO
Authors: Kuang Xianyan , Li Penghui , Liu Zhanfei , Wu Cuiqin
Published: March 2023

In the inverse solution of the rock drilling manipulator, the particle swarm optimization algorithm has been widely used, but due to the complex structure of the manipulator, its disadvantage is that the convergence speed is slow and it is easy to fall into the local optimal solution. Therefore, the adaptive annealing coefficient is introduced into the simulated annealing particle swarm optimization algorithm and improved; the overall search and convergence are improved. Through the simulation experiment of the PSO algorithm, it is proved that this method is better than the conventional PSO method in terms of convergence speed and precision, and can better solve the problem of slow convergence speed and falling into local optimum.
Autonomous landing algorithm of UAV based on Target tracking
Authors: Wan Xiaoyan , Shi Yongkang , Li Peng
Published: March 2023

The target tracking technology in the UAV autonomous landing process is studied. Based on the analysis of the occlusion, background change, and variable scale problems in the target tracking process, a scale adaptive method for UAV target tracking based on KCF (Kernelized Correlation Filter) algorithm is proposed. The original KCF target tracking framework is adopted to achieve the target position prediction function. Secondly, to address the variable scale problem of moving targets and the target loss problem caused by scale changes, the scale filter of the DSST target tracking algorithm is used. The algorithm is for estimating the scale of moving targets and generating a small-scale filter estimate to improve the tracking efficiency of the UAV for moving targets and reduce the target loss rate. The final test on the OTB dataset showed a 4% improvement in variable scale accuracy and a 2.9% improvement in variable scale success rate. A Gazebo 3D environment scene was set up under the Linux system, and UAV autonomous landing simulation experiments were conducted to verify the improved algorithm’s real-time effectiveness in the UAV autonomous landing application. The simulation results show that the improved KCF target tracking algorithm has real-time performance in the UAV autonomous landing trajectory tracking process.
Obstacle Avoidance Design of Aerial Robot Combining A star algorithm Algorithm and Optical Dynamic Capture Method
Authors: Shi Xianwei , Cai Hongzhuan , Ji Yuan
Published: March 2023

The traditional A star obstacle avoidance algorithm is based on binocular cameras for indoor positioning, which requires rich obstacle feature points and has the risk of explosion in a single indoor environment. In this paper, the method of merging the A star algorithm and optical dynamic capture is proposed. By pasting Marker points on key moving parts, the actual position of the aerial robot is calculated with the optical dynamic capture system, and compared with the target position planned by the A star algorithm and corrected in real time during a flight. Through the experimental analysis of the original acceleration of the aerial robot and different position between the target point and the actual point in the flight process, the stability and flight accuracy of the aerial robot in the flight process can be significantly improved, which has good practical application value.
Research progress and prospect of insulation characteristics of HVDC converter transformer bushing
Authors: Zhang Shiling
Published: March 2023

The paper mainly analyzes the development of the high voltage bushing is closely related to the development of power industry. With the gradual rise of the voltage level in power industry, bushing has experienced the development process from low voltage, high voltage, ultra-high voltage to ultra-high voltage. In order to meet operation requirements under the different voltage levels, the pure porcelain bushing, metal shielded bushing and capacitive bushing have also appeared in the bushing body structure, and the core material has gradually changed from the oil impregnated paper and the adhesive paper to adhesive impregnated paper. In the process of the continuous development of bushing structure and main insulation materials, the research on the high-voltage bushing mainly focuses on the material performance test of bushing, the improvement of the main insulation structure design method, and the simulation analysis of bushing voltage and heat sharing.
An Improved SSD Object Detection Algorithm Based on Attention Mechanism and Feature Fusion
Authors: Deng Xiangyu , Li Shanshan
Published: March 2023

The Single Shot MultiBox Detector (SSD) is a well-known object detection method, but its detection of small objects is not effective. This paper makes modifications to the SSD object detection method to address its insufficient semantic information in low-level feature maps, thus enhancing the detectability for small objects. First, the Feature Pyramid Network (FPN) is incorporated into the SSD so that the shallow feature map, which is primarily utilized for detecting small objects, contains more semantic information in addition to rich location information. Second, the Convolutional Block Attention Module (CBAM) is introduced to reinforce the SSD network’s capability to learn key features and thus improve missed detections. The experimental data indicate that this algorithm achieves 78.1% mAP in the PASCAL VOC2007test, a 3.9% improvement compared with the conventional SSD, and also has a great improvement compared with the Fast R-CNN and Faster R-CNN. As well as,this algorithm is better for small object detection and also meets the real-time requirements.