bluuebunny/crossref_metadata_2025 huggingface dataset:
Piezoresistive sensitivity enhancement below threshold voltage in sub-5 nm node using junctionless multi-nanosheet FETs
Authors: Kumar Nitish , Joshi Khanjan , Gupta Ankur , Singh Pushpapraj
Published: May 2024

In this paper, the piezoresistive sensitivity is enhanced by applying uniform mechanical stress (MS) on the multi-nanosheet (NS) channels of sub-5 nm junctionless field-effect transistors. The piezoresistivity of the sensing device is boosted by narrowing channel conductivity using low gate biasing and reducing physical channel width, resulting in the maximum (∼6 times higher) sensitivity observed in the subthreshold regime compared to the ON-state condition. In addition, the sensitivity is extensively increased by ∼30.3% near the threshold voltage with horizontally multi-NS stacking due to the uniform MS distribution on the multi-NS channels, which can sense slight deflection of pressure on the circular diaphragm. These results show that the tunable sensitivity of junctionless multi-channel devices is superior to the inversion mode, a consequence of the less scattering effect, better thermal stability, and low electronic noise.
A synapse with low power consumption based on MoTe2/SnS2 heterostructure
Authors: He Wenxin , Xing Yanhui , Fang Peijing , Han Zisuo , Yu Zhipeng , Zhan Rongbin , Han Jun , Guan Baolu , Zhang Baoshun , Lv Weiming , Zeng Zhongming
Published: May 2024

The use of two-dimensional materials and van der Waals heterostructures holds great potential for improving the performance of memristors Here, we present SnS2/MoTe2 heterostructure synaptic transistors. Benefiting from the ultra-low dark current of the heterojunction, the power consumption of the synapse is only 19 pJ per switching under 0.1 V bias, comparable to that of biological synapses. The synaptic device based on the SnS2/MoTe2 demonstrates various synaptic functionalities, including short-term plasticity, long-term plasticity, and paired-pulse facilitation. In particular, the synaptic weight of the excitatory postsynaptic current can reach 109.8%. In addition, the controllability of the long-term potentiation and long-term depression are discussed. The dynamic range (G
max/G
min) and the symmetricity values of the synaptic devices are approximately 16.22 and 6.37, and the non-linearity is 1.79. Our study provides the possibility for the application of 2D material synaptic devices in the field of low-power information storage.
Development and characterization of self-powered, highly sensitive optoelectronic device based on PVA-rGO nanofibers/n-Si
Authors: Yıldırım Fatma , Galehdarvand Sharmineh , Chenari Hossein Mahmoudi , Yılmaz Mehmet , Aydoğan Şakir
Published: May 2024

This study provided a promising way to fabricate low-cost and high-performance Poly (vinyl alcohol)-reduced graphene oxide (PVA-RGO) nanofibers/n-Si heterojunction photodetector. For this purpose, the hybrid heterojunction with a very-high rectification ratio (2.4 × 106) was achieved by successfully coating PVA-RGO nanofibers on n-Si wafer by electrospinning method. When the electro-optical analysis of the fabricated heterojunction photodetector under visible light depending on the light intensity, ultraviolet (UV) and infrared (IR) lights was examined in detail, it was observed that the photodetector exhibited both self-powered behavior and very high photo-response under each light sources. However, the highest optical performance was obtained under UV (365 nm) originated from PVA-RGO layer and IR (850 nm) light from both interfacial states between PVA-RGO nanofibers and Si and from Si layer. Under 365 nm UV light, the maximum performance values of R, D, ON/OFF ratio, normalized photo-dark-current ratio and external quantum efficiency (%) were obtained as 688 mA W−1, 1.15 × 1015Jones, 2.49 × 106, 8.28 × 1010 W−1 and 234%, respectively.
Effect of sandblasting and acid surface pretreatment on the specific capacitance of CuO nanostructures grown by hot water treatment for supercapacitor electrode applications
Authors: Haque Shanzida , Wang Daoyuan , Ergul Busra , Basurrah Assem , Karabacak Tansel
Published: May 2024

Crystalline copper oxide (CuO) nanostructures with micro, nano, and micro-nano surface roughness were grown on Cu sheet substrates by a facile, scalable, low-cost, and low-temperature hot water treatment (HWT) method that simply involved immersing Cu sheet in DI water at 75 °C for 24 h without any chemical additives. Various morphological features and sizes of CuO nanostructures were tuned by using different surface pretreatment techniques including acid treatment, sandblasting, or a combination of those two. The surface morphology of the prepared samples was analyzed by scanning electron microscopy. The crystal structure of the CuO nanostructures was investigated by x-ray diffraction XRD and Raman spectroscopy. To study the pseudocapacitive behavior, their potential supercapacitor performance, and equivalent series resistance, electrochemical analysis was done by cyclic voltammetry and electrochemical impedance spectroscopy for all the CuO/Cu samples in 1 M of Na2SO4 electrolyte. Among all, the best supercapacitive performance was achieved for CuO/Cu samples pretreated with Sandblasting followed by Acid treatment resulting in a specific capacitance of about 104 F g−1. The electrode with the sandblasted + acid pretreated sample showed a maximum of ∼69% capacitive retention after 2000 consecutive cycles. Our results indicate that CuO nanostructures on Cu substrates prepared with different surface pretreatment conditions and grown by HWT can be promising electrodes for supercapacitor device applications.
Feasibility and optimization of 19F MRI on a clinical 3T with a large field-of-view torso coil
Authors: Lechuga Lawrence M , Cho Monica M , Vail David M , Captini Christian M , Fain Sean B , Begovatz Paul
Published: May 2024

Objective. The objective of this work is to: (1) demonstrate fluorine-19 (19F) MRI on a 3T clinical system with a large field of view (FOV) multi-channel torso coil (2) demonstrate an example parameter selection optimization for a 19F agent to maximize the signal-to-noise ratio (SNR)-efficiency for spoiled gradient echo (SPGR), balanced steady-state free precession (bSSFP), and phase-cycled bSSFP (bSSFP-C), and (3) validate detection feasibility in ex vivo tissues. Approach. Measurements were conducted on a 3.0T Discovery MR750w MRI (GE Healthcare, USA) with an 8-channel 1H/19F torso coil (MRI Tools, Germany). Numerical simulations were conducted for perfluoropolyether to determine the theoretical parameters to maximize SNR-efficiency for the sequences. Theoretical parameters were experimentally verified, and the sensitivity of the sequences was compared with a 10 min acquisition time with a 3.125 × 3.125 × 3 mm3 in-plane resolution. Feasibility of a bSSFP-C was also demonstrated in phantom and ex vivo tissues. Main Results. Flip angles (FAs) of 12 and 64° maximized the signal for SPGR and bSSFP, and validation of optimal FA and receiver bandwidth showed close agreement with numerical simulations. Sensitivities of 2.47, 5.81, and 4.44

m

s

−
0.5

m

M

−
1

 

and empirical detection limits of 20.3, 1.5, and 6.2 mM were achieved for SPGR, bSSFP, and bSSFP-C, respectively. bSSFP and bSSFP-C achieved 1.8-fold greater sensitivity over SPGR (p < 0.01). Significance. bSSFP-C was able to improve sensitivity relative to simple SPGR and reduce both bSSFP banding effects and imaging time. The sequence was used to demonstrate the feasibility of 19F MRI at clinical FOVs and field strengths within ex-vivo tissues.
Automatic breast ultrasound (ABUS) tumor segmentation based on global and local feature fusion
Authors: Li Yanfeng , Ren Yihan , Cheng Zhanyi , Sun Jia , Pan Pan , Chen Houjin
Published: May 2024

Accurate segmentation of tumor regions in automated breast ultrasound (ABUS) images is of paramount importance in computer-aided diagnosis system. However, the inherent diversity of tumors and the imaging interference pose great challenges to ABUS tumor segmentation. In this paper, we propose a global and local feature interaction model combined with graph fusion (GLGM), for 3D ABUS tumor segmentation. In GLGM, we construct a dual branch encoder-decoder, where both local and global features can be extracted. Besides, a global and local feature fusion module is designed, which employs the deepest semantic interaction to facilitate information exchange between local and global features. Additionally, to improve the segmentation performance for small tumors, a graph convolution-based shallow feature fusion module is designed. It exploits the shallow feature to enhance the feature expression of small tumors in both local and global domains. The proposed method is evaluated on a private ABUS dataset and a public ABUS dataset. For the private ABUS dataset, the small tumors (volume smaller than 1 cm3) account for over 50% of the entire dataset. Experimental results show that the proposed GLGM model outperforms several state-of-the-art segmentation models in 3D ABUS tumor segmentation, particularly in segmenting small tumors.
Physical insights from the aspect ratio dependence of turbulence in negative triangularity plasmas
Authors: Balestri A , Ball J , Coda S , Cruz-Zabala D J , Garcia-Munoz M , Viezzer E
Published: May 2024

In this work, we study the impact of aspect ratio

A
=

R
0

/

r

(the ratio of major radius R
0 to minor radius r) on the confinement benefits of negative triangularity (NT) plasma shaping. We use high-fidelity flux tube gyrokinetic GENE simulations and consider several different scenarios: four of them inspired by TCV experimental data, a scenario inspired by DIII-D experimental data and a scenario expected in the new SMART spherical tokamak. The present study reveals a distinct and non-trivial dependence. NT improves confinement at any value of A for ITG turbulence, while for TEM turbulence confinement is improved only in the case of large and conventional aspect ratios. Additionally, through a detailed study of a large aspect ratio case with pure ITG drive, we develop an intuitive physical picture that explains the beneficial effect of NT at large and conventional aspect ratios. This picture does not hold in TEM-dominated regimes, where a complex synergistic effect of many factors is found. Finally, we performed the first linear gyrokinetic simulations of SMART, finding that both NT and PT scenarios are dominated by micro-tearing-mode (MTM) turbulence and that NT is more susceptible to MTMs at tight aspect ratio. However, a regime where ITG dominates can be found in SMART, and in this regime NT is more linearly stable.
Dynamics of switching optical soliton in fiber with sixth order dispersion and inter modal dispersion
Authors: Parasuraman E , Muniyappan A , Ravichandran R
Published: May 2024

This work pertains to the study of switching soliton in fiber for nonlinear Schrödinger (NLS) equation with the presence of higher order dispersion and inter modal dispersion (IMD). The nonlinear wave in the optical fiber are described by the NLS equation which having the second order, fourth order, fifth order, sixth order dispersion, higher order nonlinearity and IMD. The main goal of the paper is to examine the sixth order dispersion on nonlinear wave in the fiber with the conditions of IMD. Hence, we employ the Bäcklund transformation of the Riccati equation (BTRE) approach to NLS equation and obtain the soliton solution. By the use of soliton solution along with graphical snapshots, we provide the conditions for forming switching solition in optical fiber and also analyze the effect of sixth order dispersion in fiber. The stability of the solution of NLS equation is also addressed.
Two-dimensional intrinsic ferromagnetic materials of Janus 2H-NbXY (X, Y = S, Se and Te, X ≠ Y) monolayers with high Curie temperature and large magnetic anisotropy
Authors: Wang Tianxing , Tian Tian , Li Mengxin , Zhao Xu , Xia Congxin , An Yipeng , Wei Shuyi
Published: May 2024

Two-dimensional (2D) intrinsic ferromagnetic materials with large magnetic anisotropy (MA) and high Curie temperature (TC) are desirable for low-dimensional spintronic applications. In this work, a highly stable Janus NbXY (X, Y = S, Se and Te, X ≠ Y) monolayers with intrinsic ferromagnetism is investigated by using first-principles calculations. The results demonstrate that the MAE values of the NbSSe, NbSTe and NbSeTe MLs are as high as −2.185 meV, −4.013 meV and −4.495 meV per unit cell, respectively, which is higher than the previously reported 2D intrinsic ferromagnetic materials such as FeBrI, NiI2, and VSSe MLs etc. And they are still large enough for practical applications. The Curie temperature (Tc) is estimated to be 160 K for NbSSe monolayer, 260 K for NbSTe monolayer, and 200 K for NbSeTe monolayer based on Monte Carlo simulation. The MAE and Tc could be effectively controlled and enhanced by the biaxial strains. The MAE of NbSSe, NbSTe and NbSeTe MLs can be increased by 8.7%, 24.9% and 14.1%, and reach up to −2.375, −5.015 and −5.131 meV at 5% compressive strain, respectively. Remarkably, at 5% tensile strain, the room temperature

T

c

of 300 K can be reached for NbSTe monolayer, which is rather promising for its practical application. The large magnetic anisotropy energy and controllable Curie temperature make the NbXY monolayers a promising candidate for applications in spintronic devices at the nanoscale and in high-density data storage.
Q-switched pulse generation in L-band region with polyacrylonitrile saturable absorber
Authors: Ahmad Aeriyn D , Salam Sameer , Mokhtar Norrima , Arof Hamzah , Apsari Retna , Hamida Belal Ahmed , Harun Sulaiman W
Published: May 2024

In this study, we assess the practicality of using Polyacrylonitrile (PAN) as a saturable absorber (SA) for generating Q-switched pulses within an erbium-doped fibre laser (EDFL) cavity. A successful combination of PAN, a resin material, and polyvinyl alcohol resulted in the formation of a SA film. This film was utilised to generate stable Q-switched pulses operating in a long-wavelength band of 1572 nm. The greatest repetition rate achieved was 66.1 kHz, while the minimum pulse width was 2.43 μs. The maximum pulse energy was achieved at 52 nJ and measured at a pump power of 175.9 mW. To the best of our knowledge, this study is the first report of EDFL passive Q-switching employing a PAN absorber.
The state of the dark energy equation of state circa 2023
Authors: Escamilla Luis A. , Giarè William , Valentino Eleonora Di , Nunes Rafael C. , Vagnozzi Sunny
Published: May 2024

We critically examine the state of current constraints on the dark energy (DE) equation of state (EoS)w. Our study is motivated by the observation that, while broadly consistent with the cosmological constant valuew= -1, several independent probes appear to point towards a slightly phantom EoS (w∼ -1.03) which, if confirmed, could have important implications for the Hubble tension. We pay attention to the apparent preference for phantom DE fromPlanckCosmic Microwave Background (CMB) data alone, whose origin we study in detail and attribute to a wide range of (physical and geometrical) effects. We deem the combination ofPlanckCMB, Baryon Acoustic Oscillations, Type Ia Supernovae, and Cosmic Chronometers data to be particularly trustworthy, inferring from this final consensus datasetw= -1.013+0.038-0.043, in excellent agreement with the cosmological constant value. Overall, despite a few scattered hints, we find no compelling evidence forcing us away from the cosmological constant (yet).
Primordial origin of supermassive black holes from axion bubbles
Authors: Kasai Kentaro , Kawasaki Masahiro , Kitajima Naoya , Murai Kai , Neda Shunsuke , Takahashi Fuminobu
Published: May 2024

We study a modification of the primordial black hole (PBH) formation model from axion bubbles.
We assume that the Peccei-Quinn scalar rolls down in the radial direction from a large field value to the potential minimum during inflation, which suppresses the axion fluctuations and weakens the clustering of PBHs on large scales.
We find that the modified model can produce a sufficient number of PBHs that seed the supermassive black holes while avoiding the observational constraints from isocurvature perturbations and angular correlation of the high-redshift quasars.
A study on vector mediator top-philic dark matter
Authors: Hu Yanyan , Liu Yandong , Liu Yuanyuan
Published: May 2024

We conducted a study on a simplified dark matter model that introduces a vector-like intermediate particle, facilitating exclusive interactions between dark matter and the top quark in the Standard Model. The analysis focused on the relic density of Dirac-type fermion dark matter and highlighted the complementary role of direct detection in constraining the dark matter model. Notably, in instances when dark matter mass is small, the tree-level two-body annihilation process experiences suppression. In such scenarios, the contributions of the three-body process (

χ

χ

¯

→
t

b

¯

W

−

) and the one-loop process (

χ

χ

¯

→
gg

) dominate the relic abundance. With regard to direct detection, calculations were performed for the two-loop contribution to the dark-matter–gluon interaction, yielding the corresponding spin-independent scattering cross section.
An approximate Kerr–Newman-like metric endowed with a magnetic dipole and mass quadrupole
Authors: Frutos-Alfaro Francisco
Published: May 2024

Approximate all-terrain spacetimes for astrophysical applications are presented. The metrics possess five relativistic multipole moments, namely, mass, rotation, mass quadrupole, charge, and magnetic dipole moment. All these spacetimes approximately satisfy the Einstein–Maxwell field equations. The first metric is generated using the Hoenselaers–Perjés method from given relativistic multipoles. The second metric is a perturbation of the Kerr–Newman metric, which makes it a relevant approximation for astrophysical calculations. The last metric is an extension of the Hartle–Thorne metric that is important for obtaining internal models of compact objects perturbatively. The electromagnetic field is calculated using Cartan forms for locally non-rotating observers. These spacetimes are relevant for inferring properties of compact objects from astrophysical observations. Furthermore, the numerical implementations of these metrics are straightforward, making them versatile for simulating potential astrophysical applications.
Observational appearances of hairy black holes in the framework of gravitational decoupling
Authors: Liang Yizhi , Lyu Xin , Tao Jun
Published: May 2024

We investigate the observational appearance of static and spherically symmetric hairy black holes in the framework of gravitational decoupling with the weak energy condition (WEC). Two types of thin illumination conditions are studied: spherical accretion and disk accretion. As the hairy parameter increases, the size of the photon sphere and photon rings in both models decreases, and the overall luminosity attenuation becomes more pronounced. In spherical accretion, the luminosity of infalling accretion is significantly lower than that of stationary accretion. In disk accretion the luminosity of the black hole is contributed by direct emission, the lensing ring and the photon ring. Employing four types of astrophysical disk luminosity model, we investigate the appearance of halos and note that their luminosities do not superimpose when the source is on or beyond the innermost stable circular orbit.
The tightness of the measure-based method to estimate quantum coherence
Authors: Zhang Zimeng , Li Yongming , Luo Yu
Published: May 2024

With the advancement of quantum information science, the understanding of quantum coherence has become increasingly important. In this paper, we investigate the effects of different channels on quantum states and analyze the evolution process of quantum states during channel transmission. Our findings reveal variations in the impact of different channels on quantum coherence. Additionally, we explore the estimation of lower bounds on coherence after passing through these diverse channels. We observe that channel transmission has a certain influence on the tightness of lower bounds on quantum coherence. We conduct a detailed analysis of this influence and propose improvement method to enhance the tightness of the lower bound estimation. Based on our research results, we draw conclusions that unveil the characteristics of quantum coherence under different channel conditions. Furthermore, we provide an effective estimation method and improvement strategies to accurately assess the coherence of quantum states. This research holds significant implications for further advancements in quantum information processing and quantum communication.
Control of interfacial reaction and defect formation in Gd/Bi2Te2.7Se0.3 composites with excellent thermoelectric and magnetocaloric properties
Authors: Xue 薛 Tianchang 天畅 , Wei 魏 Ping 平 , Liu 刘 Chengshan 承姗 , Li 李 Longzhou 龙舟 , Zhu 朱 Wanting 婉婷 , Nie 聂 Xiaolei 晓蕾 , Zhao 赵 Wenyu 文俞
Published: May 2024

The method to combine thermoelectric (TE) and magnetocaloric (MC) cooling techniques lies in developing a new material that simultaneously possesses a large TE and good MC cooling performance. In this work, using n-type Bi2Te2.7Se0.3 (BTS) as the TE base material and Gd as the second-phase MC material, Gd/BTS composites were prepared by the spark plasma sintering method. In the composites, interfacial reaction between Gd and BTS was identified, resulting in the formation of GdTe, which has a large impact on the electron concentration through the adjustment of defect concentration. The MC/TE composite containing 2.5 wt% Gd exhibited a ZT value of 0.6 at 300 K, essentially retaining the original TE performance, while all the composites largely maintained the excellent MC performance of Gd. This work provides a potential pathway to achieving high performance in MC/TE composites.
Single crystal growth and transport properties of narrow-bandgap semiconductor RhP2
Authors: Wu 吴 De-Sheng 德胜 , Zheng 郑 Ping 萍 , Luo 雒 Jian-Lin 建林
Published: May 2024

We report the growth of high-quality single crystals of RhP2, and systematically study its structure and physical properties by transport, magnetism, and heat capacity measurements. Single-crystal x-ray diffraction reveals that RhP2 adopts a monoclinic structure with the cell parameters a = 5.7347(10) Å, b = 5.7804(11) Å, and c = 5.8222(11) Å, space group P21/c (No. 14). The electrical resistivity ρ(T) measurements indicate that RhP2 exhibits narrow-bandgap behavior with the activation energies of 223.1 meV and 27.4 meV for two distinct regions, respectively. The temperature-dependent Hall effect measurements show electron domain transport behavior with a low charge carrier concentration. We find that RhP2 has a high mobility μ
e ∼ 210 cm2⋅V−1⋅s−1 with carrier concentrations n
e ∼ 3.3 × 1018 cm−3 at 300 K with a narrow-bandgap feature. The high mobility μ
e reaches the maximum of approximately 340 cm2⋅V−1⋅s−1 with carrier concentrations n
e ∼ 2 × 1018 cm−3 at 100 K. No magnetic phase transitions are observed from the susceptibility χ(T) and specific heat C
p(T) measurements of RhP2. Our results not only provide effective potential as a material platform for studying exotic physical properties and electron band structures but also motivate further exploration of their potential photovoltaic and optoelectronic applications.
Moiré superlattices arising from growth induced by screw dislocations in layered materials
Authors: Tian 田 Fuyu 伏钰 , Faizan Muhammad , He 贺 Xin 欣 , Sun 孙 Yuanhui 远慧 , Zhang 张 Lijun 立军
Published: May 2024

Moiré superlattices (MSLs) are modulated structures produced from homogeneous or heterogeneous two-dimensional layers stacked with a twist angle and/or lattice mismatch. Enriching the methods for fabricating MSL and realizing the unique emergent properties are key challenges in its investigation. Here we recommend that the spiral dislocation driven growth is another optional method for the preparation of high quality MSL samples. The spiral structure stabilizes the constant out-of-plane lattice distance, causing the variations in electronic and optical properties. Taking SnS2 MSL as an example, we find prominent properties including large band gap reduction (∼ 0.4 eV) and enhanced optical activity. First-principles calculations reveal that these unusual properties can be ascribed to the locally enhanced interlayer interaction associated with the Moiré potential modulation. We believe that the spiral dislocation driven growth would be a powerful method to expand the MSL family and broaden their scope of application.
Cross-method Analysis of Corotation Radii Data Set for Spiral Galaxies
Authors: Kostiuk V. S. , Marchuk A. A. , Gusev A. S.
Published: May 2024

A corotation radius is a key characteristic of disk galaxies that is essential to determine the angular speed of the spiral structure Ω
p
, and therefore understand its nature. In the literature, there are plenty of methods to estimate this value, but do these measurements have any consistency? In this work, we collected a data set of corotation radius measurements for 547 galaxies, 300 of which had at least two values. An initial analysis reveals that most objects have rather inconsistent corotation radius positions. Moreover, a significant fraction of galactic disks is distinguished by a large error coverage and almost uniform distribution of measurements. These findings do not have any relation to spiral type, Hubble classification, or presence of a bar. Among other reasons, obtained results could be explained by the transient nature of spirals in a considerable part of galaxies. We have made our collected data sample publicly available, and have demonstrated on one example how it could be useful for future research by investigating a winding time value for a sample of galaxies with possible multiple spiral arm patterns.
Stability and transport of gyrokinetic critical pedestals
Authors: Parisi J.F. , Nelson A.O. , Guttenfelder W. , Gaur R. , Berkery J.W. , Kaye S.M. , Barada K. , Clauser C. , Diallo A. , Hatch D.R. , Kleiner A. , Lampert M. , Macwan T. , Menard J.E.
Published: May 2024

A gyrokinetic threshold model for pedestal width–height scaling prediction is applied to multiple devices. A shaping and aspect ratio scan is performed on National Spherical Torus Experiment (NSTX) equilibria, finding

Δ

ped

=
0.92

A

1.04

κ

−
1.24

0.38

δ

β

θ
,

ped

1.05

for the wide-pedestal branch with pedestal width

Δ

ped

, aspect ratio A, elongation κ, triangularity δ, and normalized pedestal height

β

θ
,

ped

. The width–transport scaling is found to vary significantly if the pedestal height is varied either with a fixed density or fixed temperature, showing how fueling and heating sources affect the pedestal density and temperature profiles for the kinetic-ballooning-mode (KBM) limited profiles. For an NSTX equilibrium, at fixed density, the wide branch is

Δ

ped

=
0.028

(

q
e

/

Γ
e

−
1.7
)

1.5

∼

η
e

1.5

and at fixed temperature

Δ

ped

=
0.31

(

q
e

/

Γ
e

−
4.7
)

0.85

∼

η
e

0.85

, where

q
e

and

Γ
e

are turbulent electron heat and particle fluxes and

η
e

=
∇
ln
⁡

T
e

/

∇
ln
⁡

n
e

for an electron temperature

T
e

and density

n
e

. Pedestals close to the KBM limit are shown to have modified turbulent transport coefficients compared to the strongly driven KBMs. The role of flow shear is studied as a width–height scaling constraint and pedestal saturation mechanism for a standard and lithiated wide pedestal discharge. Finally, the stability, transport, and flow shear constraints are combined and examined for an NSTX experiment.
Heterogeneous Feature Fusion for Improving Performance of Action Detection
Authors: Babazaki Yasunori , Iwamoto Kota , Takahashi Katsuhiko , Li Kai , Patel Deep , Kruus Erik , Peter Graf Hans
Published: May 2024

We present a novel framework aimed at improving video action detection through the integration of heterogeneous features. Conventional action detection methods which focus on modeling the relationships between person/object instances rely exclusively on video features and do not exploit valuable intra-instance heterogeneous features, such as person pose, positional information or object category, that can support action recognition. Our proposed framework, termed Heterogeneous Feature Fusion (HFF) framework, addresses this limitation by integrating such intra-instance heterogeneous features for person/object instances, and can improve existing action detection methods. To efficiently exploit each heterogeneous feature, which vary in importance depending on actions and/or scenes, we introduce an attention mechanism to dynamically enhance important heterogeneous features within an instance. Experiments on JHMDB and AVA v2.2 datasets show that our HFF significantly enhances the action detection performance of two existing methods.
Adaptive Sampling Offspring Generation Strategy for Multi-objective Optimization
Authors: Wang Ningning , Fan Jun , Liu Tingrui , Kang Honglong , Zhang Wenbo , Song Shenmin
Published: May 2024

A covariance adaptive sampling offspring generation strategy (CASS) based on fuzzy clustering is proposed, and a multi-objective distribution estimation algorithm (MEDCA) based on this strategy is introduced. The GK-FCM clustering partitioning strategy is designed to build a Gaussian model for each individual, collectively approximating the manifold of the Pareto solution set and generating offspring through sampling. The introduction of an individual’s survival generation adapts the individual’s preference for exploration and exploitation. This is achieved by incorporating it as a scaling factor of the covariance matrix in the sampling model, in order to satisfy the individual’s preferences for development and exploration in different evolutionary stages. This method significantly improves the performance of MEDCA in solving complex multi-objective optimization problems through covariance matrix adaptation sampling strategy and scaling factor adaptation strategy. The experimental results demonstrate the advantages of MEDCA in the application of offspring generation strategies during model sampling.
Multi-Scale Contextual Swin Transformer for Crop Image Segmentation
Authors: Xu Xiaoyu , Zou Jinding , Cai Jie , Zou Dafang
Published: May 2024

Combining UAV-based remote sensing with deep learning for image segmentation is a particularly innovative and effective technology in modern agriculture. This approach allows for detailed and precise analysis of agricultural fields, such as crop monitoring, yield prediction, and irrigation management, enhancing decision-making and farm management practices. Inspired by the recent advancements of Transformers in computer vision, this paper introduces the Multi-Scale Contextual Swin Transformer (MSC-Swin), a novel model for precise segmentation of UAV crop images. MSC-Swin innovatively combines a Swin Transformer architecture for detailed feature extraction with pooling operations to utilize multi-scale contextual information. Our extensive experimentation demonstrates that MSC-Swin not only achieves state-of-the-art performance on the Barley Remote Sensing dataset, with a record mIoU of 86.4% on the test set, but also exhibits robustness and excellent generalizability.
Research on deflection correction performance of movable crossbeam during pressurization of ultra-large hydraulic press
Authors: Li Xiaohui , Wang Jie , Hao Tiewen , Li Defei , Tan Jianping , Han Kunpeng , Liu Yao , Huang Xiaoxuan
Published: May 2024

In this paper, the deflection of the movable crossbeam during the pressurization process of the ultra-large hydraulic press is studied. The electromechanical and hydraulic systems of the ultra-large hydraulic press are analyzed, and a joint AMESim-ADAMS simulation model of the mechanical system, the oil system, and the correction control system are established. The simulation analyzes the deflection control of the working cylinder in the 1600 MN pressurized state, the movable crossbeam in the positive load without deflection correction, positive load with deflection correction, eccentric load with 300 mm of deflection in X-positive direction, and eccentric load with 300 mm of deflection in XZ-positive direction. The results show that the correction control system needs to be turned on synchronously at the beginning of the pressurization; under the pressure of 1600 MN and the maximum eccentricity of 300 mm, the velocity error of the movable crossbeam can be controlled within 7 %, and the parallel control precision can reach 0.14 mm/m.
Topology optimization of the wheel frame of the tracked robot with multiple working conditions and multiple objectives
Authors: Wang Jinghua , Huang Jiangnan , Li Jinyu , Wang Chen
Published: May 2024

Based on ensuring the static stiffness and dynamic vibration frequency of the caterpillar robot wheel frame under various working conditions, the lightweight design of the caterpillar robot wheel frame is realized. The compromise programming approach is used to establish the multi-objective optimization function and three typical target conditions are simulated and analyzed. An analytic hierarchy process is used to determine the weight coefficient of each target working condition, and the topology optimization of the wheel frame of the tracked robot is carried out comprehensively, considering multi-working conditions and multi-target. The secondary design of the optimized rear wheel frame was carried out, as a result of which, the mass was reduced by 8.4% after optimization, and the first-order frequency was increased by 20 Hz after optimization. The optimized rear wheel frame strength and stiffness met the requirements.
Design and simulation analysis of heat dissipation structure of motherboard of a certain type of portable rugged computer
Authors: Li Shaodong , Guo Xiao
Published: May 2024

The portable rugged computer generally needs to adapt to high temperatures, hot and humid, and other harsh environments, while taking into account its portability, the machine cooling space is limited, and the motherboard carries the CPU, graphics cards, and other major heat-producing components. Therefore, some problems often occur due to the irrational design of the motherboard cooling structure, resulting in poor adaptability to high-temperature environments, arithmetic performance being difficult to fully play, and so on. In this paper, based on the use of a certain type of portable rugged computer requirements, a motherboard cooling structure is designed through the thermal structure, fan and increasing the heat dissipation area and other forms, and the type of computer cooling effect has been measured by simulation analysis and experimental verification to verify that it can enhance the cooling effect, to provide a better reference for the same type of portable rugged computer motherboard cooling structure design.
Direct torque motor control technology based on NPC three-level SVPWM
Authors: Li Zesheng , Li Lin
Published: May 2024

This paper introduces a direct torque control technology based on NPC three-level SVPWM. It uses the Matlab platform to build a simulation model. It verifies the ideal waveform of the torque, magnetic chain, and current of the NPC-SVPWM direct torque control system under high speed and low speed with no load and load. This technique improves the waveform of the stator current and stator magnetic chain and solves the problem of the switching frequency not being fixed. Through this technique, it not only retains the robustness of the direct torque technique to the parameter change, but also effectively reduces the torque pulsation.
Research on VIENNA rectifier QPR control and soft start
Authors: Gao Guangwei , Chen Xikun , Sun Ze , Xu Haotian , Ju Chenyu , Zhang Kesong
Published: May 2024

The principle and operation of the VIENNA rectifier is examined and the VIENNA mathematical model is developed. To address the issue that the three-phase VIENNA rectifier’s double PI controller finds it challenging to attain both rapidity and accuracy, a double closed-loop control approach consisting of inner loop quasi-proportional resonant control (QPR) and outer loop PI control is created. Aiming at the problems of inrush current on the grid side and DC bus voltage overshoot caused by the VIENNA rectifier in the startup process, the paper makes a theoretical analysis and designs a soft startup strategy. Then, the simulation model of the three-phase VIENNA rectifier control system was built in Simulink, which verified the correctness of the QPR control strategy and soft start scheme. Finally, an 8-kW prototype is set up, and the experimental results further confirm the effectiveness of the slope setting of the current.
Exploration of a high-precision measurement scheme for current sensors based on diamond NV color centers
Authors: Zhao Long , Wang Xin , Qiu Rujia , Song Dongbo , Tian Teng , Geng Jiaqi , Zhao Bowen , Zhang Shaochun
Published: May 2024

A high-precision measurement scheme for current sensors based on diamond NV color centers was verified. In the research process, diamond crystals containing a large number of NV color centers are applied as the probe of the sensor, and the magnetic field generated by the current is measured to explore the relationship between the current intensity and the fluorescence intensity of the NV color centers and the polarization resonance, to carry out simulation experiments, and finally to obtain the results of the effect of the concentration of the NV color centers on the performance of the sensor. The results of simulation experiments show that the accuracy of the current measurement is within 100-500 A, and the result is 0.3%. By applying NV color centers to current measurement, good results have been obtained in terms of accuracy and frequency response range, enabling high-precision current measurement as well as providing monitoring and analysis of high-frequency current inrush.
Residual stress analysis of plasma sprayed coatings through the weak magnetic field testing method
Authors: Zhao Chenguang , Zhan Xianglin , Wang Zhipeng
Published: May 2024

A proposed technique for swiftly evaluating coating stress variations involves utilizing weak magnetic detection under geomagnetic field conditions. This method examines the surface magnetic induction strength on uncoated test specimens, analyzing the magnetic induction change pre- and post-spraying. Employing the Almen test method, the assessment of specimen deflection and residual stress magnitude affirms the viability of weak magnetic detection for assessing coating residual stress. The experimental findings establish a direct link between the rate of magnetic induction intensity change and residual stress magnitude through polynomial fitting, suggesting that weak magnetic detection can preliminarily analyze coating stress variation.
Research on WSN clustering algorithm of firefly algorithm to optimize k-means
Authors: Zheng Xinying
Published: May 2024

Aiming at the problem that uneven clustering of wireless sensor networks leads to large energy consumption differences between clusters and short network lifetime, this paper proposes a clustering routing algorithm of WSN based on the Firefly algorithm to optimize k-means (FAKMC). This paper mainly studies the clustering stage of the network, adopts the k-means algorithm for node partition, and uses the improved FA to optimize the sensitive problem of the initial clustering centre of k-means. Simulation results show that, compared to LEACH and k-means, the clustering result proposed in this paper is more uniform and can extend the network life cycle.
Research on prediction of water target motion status of unmanned surface vehicle based on lidar
Authors: Bao Jiawei , Wang Fei , He Yunqian , Wang Xiaochuan , Lu Zhiqing , Miao Songcheng
Published: May 2024

To improve the perception ability of unmanned boats on water targets and improve the autonomous collision avoidance function of unmanned boats, the problem of target motion state prediction is studied and a method for predicting the motion state of unmanned water targets based on lidar is proposed. Firstly, a three-dimensional point cloud space model is established and the down-sampling and clutter filtering are completed through various filters. Secondly, based on European clustering target segmentation, a target tracking algorithm combined with 3D-IOU metric is proposed to achieve target tracking. Finally, the Kalman filter is introduced for denoising, combined with the iterative closest point algorithm (Iterative Closest Point, ICP) and the centroid calculation algorithm to realize the prediction of the target speed and course. After the test on the lake, the method can meet the real-time requirements, complete the accurate prediction of the target motion state and control the error at a low level. At the same time, this method can also lay the foundation for the development of subsequent autonomous navigation tasks of unmanned vehicles.
Improved weighted centroid localization algorithm based on multiple magnetic beacons
Authors: Wang Zixuan , Huang Yongming , Chen Jun , Wang Chaowen
Published: May 2024

To address challenges associated with the traditional drill positioning method, which demands manual walking tracking and imposes stringent environmental conditions, this paper introduces an improved weighted centroid localization (WCL) algorithm based on multiple magnetic beacons. This algorithm alleviates the environmental requirements. Initially, a magnetic beacon measurement model immune to sensor attitude is formulated, followed by the development of a positioning model based on multiple magnetic beacons. The WCL algorithm is then introduced and refined for positioning with multiple magnetic beacons. Finally, the effectiveness of the proposed approach is validated through simulation experiments, revealing an average error of 0.632 m in large-scale positioning. This demonstrates clear advantages over traditional methods, making it highly applicable.
Far UV coatings for liquid-Ar time projection chambers
Authors: Larruquert J.I. , López-Reyes P. , Gutiérrez-Luna N. , Honrado-Benítez C. , Pesudo V.
Published: May 2024

Liquid Ar (LAr) and liquid Xe (LXe) time projection chambers (TPCs) are used for many applications in neutrino physics and direct dark matter searches. The performance of these detectors, particularly dual-phase ones, depends very strongly on the efficiency for detecting the far ultraviolet (FUV) scintillation light. Such detection is particularly challenging for LAr, in which the strongest scintillation feature is observed at a wavelength of 127 nm (175 nm for LXe). The current mainstream approach is covering the optical surfaces with a wavelength shifter, which absorbs de FUV light and emits at wavelengths that overlap with the optical band, where commercial devices have higher detection efficiency. This work presents coatings designed to enhance the optical properties of the detector materials and to be an alternative to the current technique. In particular, two possible coatings are proposed: narrowband and broadband FUV reflective coatings. The narrowband coatings are tuned at the FUV scintillation light. They provide a large reflectance at the design angle; additionally, these coatings are naturally transparent at longer wavelengths, which might be useful to selectively detect the wavelength of interest. Their performance is evaluated taking into account the refractive index of LAr and as a function of the angle of incidence. The same calculations are performed for an aluminium-based broadband mirror. Finally, the effect on reflectance of submerging both sorts of mirrors at liquid nitrogen temperature is presented.
A low crosstalk 768-channel of 14-bit analog to digital converters for high resolution array of detectors
Authors: Dzahini D. , Zeloufi M. , Gallin-Martel L.
Published: May 2024

This paper presents the design and measurement results of a 768-channel of a 14-bit analog to digital converters. Each sampling channel is equivalent to a pitch of only 8.5 μm with a possible sampling rate from 40 KS/s up to 100 KS/s. Test results show crosstalk of just +/-1 LSB. The circuit architecture and layout structure make it scalable to an exceptionally large format of detectors beyond 1000 channels. The circuit is designed to be used as a side element for multi-channel readout systems or as an IP for transfer to very dense integrated circuits.
Muon beamtest results of high-density glass scintillator tiles
Authors: Du Dejing , Liu Yong , Cai Hua , Chen Danping , Hua Zhehao , Han Jifeng , Liu Shan , Qi Baohua , Qian Sen , Ren Jing , Sun Xinyuan , Tang Gao , Yang Dong , Yin Shenghua , Zhang Minghui
Published: May 2024

To achieve the physics goal of precisely measure the Higgs,
Z, W bosons and the top quark, future electron-positron colliders
require that their detector system has excellent jet energy
resolution. One feasible technical option is the high granular
calorimetery based on the particle flow algorithm (PFA). A new
high-granularity hadronic calorimeter with glass scintillator tiles
(GSHCAL) has been proposed, which focus on the significant
improvement of hadronic energy resolution with a notable increase of
the energy sampling fraction by using high-density glass
scintillator tiles. The minimum ionizing particle (MIP) response of
a glass scintillator tile is crucial to the hadronic calorimeter, so
a dedicated beamtest setup was developed for testing the first batch
of large-size glass scintillators. The maximum MIP response of the
first batch of glass scintillator tiles can reach up to 107
p.e./MIP, which essentially meets the design requirements of the
CEPC GSHCAL. An optical simulation model of a single glass
scintillator tile has been established, and the simulation results
are consistent with the beamtest results.
The novel equipment for measuring internal stress in acrylic
Authors: Yang Xiaoyu , Heng Yuekun , Chen Zhiqiang , Wei Cunfeng , Zhang Zhiming , Wei Long
Published: May 2024

Acrylic is widely used in aquariums, windows of planes and
submarines, and even scientific experiments like the Sudbury
Neutrino Observatory (SNO) and the Jiangmen Underground Neutrino
Observatory (JUNO). Internal stress has a significant impact on the
properties and characteristics of acrylic such as strength, fracture
and creep, which is highly concerned and has become a hotspot in
research field. The measurement of internal stress is an important
issue, which includes two aspects - the calibration of
stress-optical coefficient of acrylic and the measurement of
birefringence optical path difference (BOPD) caused by internal
stress. The measuring equipment mainly realize the measurement of
BOPD, and currently have the largest dynamic range of
50–3000 nm. Dynamic range is considered as one of the core
performance indicators of measuring equipment, and a larger dynamic
range is urgently required to meet the needs of different
scenarios. The novel equipment for measuring internal stress in
acrylic has been designed and developed based on photo-elastic
principle and spectrometric method, which has the dynamic range of
20–12000 nm and the uncertainty of stress measurement better than
3%. The measuring principle, components, functions and measurements
of the novel measuring equipment are introduced and discussed in
this article.