bluuebunny/crossref_metadata_2025_split huggingface dataset:
Accessing dual toroidal modes in terahertz plasmonic metasurfaces through polarization-sensitive resonance hybridization
Authors: Mallick Soumyajyoti , Rane Shreeya , Acharyya Nityananda , Roy Chowdhury Dibakar 
Published: May 2023

Abstract
Plasmonic metasurfaces have been quite a fascinating framework to invoke transformation of incident electromagnetic waves for a while now. Oftentimes, the building block of these metasurfaces or the unit cells consists of two or more meta-resonators. As a consequence, near-field coupling amongst these constituents may occur depending upon the spatial and spectral separation of the individual elements (meta-resonators). In such coupled structures resonance mode-hybridization can help in explaining the formation and energy re-distribution among the resonance modes. However, the coupling of these plasmonic modes is extremely sensitive to the polarization of the incident probe beam and offers ample amount of scope to harness newer physics. A qualitative understanding of the same can be attained through mode-hybridization phenomena. In this context, here, we have proposed a multi-element metastructure unit cell consisting of split ring and dipole resonators aiming to explore the intricate effects of the polarization dependency of these hybridized modes. Multi-resonator systems with varied inter-resonator spacing (sp = 3.0, 5.0, and 7.0 μm) are fabricated and characterized in the terahertz domain, showing a decrement in the frequency detuning (δ) by 30% (approx.) for a particular polarization orientation of THz probe beam. However, no such detuning is observed for the other orthogonal polarization configuration. Therefore, modulation of the resonance-hybridization is strongly dependent on the terahertz beam polarization. Further, as an outcome of the strong near-field coupling, the emergence of dual toroidal modes is observed. Excitation of toroidal modes demands thoughtful mode engineering to amplify the response of these otherwise feeble modes. Such modes are capable of strongly confining electromagnetic fields due to higher Quality (Q-) factor. Our experimental studies have shown significant signature of the presence of these modes in the Terahertz (THz) domain, backed up by rigorous numerical investigations along with multipole analysis. The calculated multipole decomposition demonstrates stronger scattering amplitude enhancements (∼7 times) at both the toroidal modes compared to off-resonant values. Such dual toroidal resonances are capable of superior field confinements as compared to single toroidal mode, and therefore, can potentially serve as an ideal testbed in developing next-generation multi-mode bio-sensors as well as realization of high Q-factor lasing cavities, electromagnetically induced transparency, non-radiating anapole modes, novel ultrafast switching, and several other applications.
Exploiting potentialities for space-based quantum communication network: downlink quantum key distribution modelling and scheduling analysis
Authors: Wang Xingyu , Li Taoyong , Dong Chen , Wei Jiahua , Yu Huicun , Zhao Shanghong , Shi Lei 
Published: May 2023

Abstract
The goal of the space-based quantum network is to form the backbone of the quantum internet for long-distance secure data transfer, networked distributed quantum information processing, and other applications. Consider that the quantum network evolved from a recent form where a satellite performs a sequence of satellite-to-ground quantum key distribution (SatQKD) missions that allow any two ground nodes to have the symmetric encryption keys, we here develop a framework for the SatQKD downlink modelling and scheduling analysis. Incorporated with the orbital calculation and the meteorological data to downlink SatQKD modelling, the dynamic characteristics of the satellite-to-ground optical transmission could be simulated. Our work shows that the satellite downlink scheduling allows for the possibility to consider different strategies for SatQKD missions such as extending connection for distant ground nodes, prioritized delivery and promoting keys utilization, which may guide design and analysis of future missions for future satellite application.
A novel coercivity enhancement method of Nd-Ce-Fe-B magnets by adjusting anisotropy field distribution and magnetostatic field distribution
Authors: Shen Peng , Wang Chao , Li Jindong , Zhao Yuxin , Sun Xu , Han Rui , Fang Yikun , Zhou Dong , Zhu Minggang , Li Wei 
Published: May 2023

Abstract
In order to give full play to the potential of Nd-Ce-Fe-B magnets and increase the coercivity of magnets with a fixed average composition, the influence of the cooperation effect of anisotropy field and magnetostatic field on their coercivity was studied. Micromagnetic simulations revealed that neither the most heterogeneous composition distribution nor the most homogeneous composition resulted in the highest coercivity. This is due to the variation in a critical field H

crit
which quantifies the cooperation effect of anisotropy field and magnetostatic field. By subtly changing the composition distribution of the Nd-Ce-Fe-B magnets, this work provides a new perspective for further improvement of the coercivity. This adjustment modifies the anisotropy field distribution and the magnetostatic field distribution.
Hall effect on the magnetic reconnections during the evolution of a three-dimensional magnetic flux rope
Authors: Bora K , Agarwal Satyam , Kumar Sanjay , Bhattacharyya R 
Published: May 2023

Abstract
We present a novel Hall magnetohydrodynamics (HMHD) numerical simulation of a three-dimensional (3D) magnetic flux rope (MFR)—generated by magnetic reconnections from an initial 3D bipolar sheared field. Magnetic reconnections during the HMHD evolution are compared with the MHD. In both simulations, the MFRs generate as a consequence of the magnetic reconnection at null points which has not been realized in contemporary simulations. Interestingly, the evolution is faster and more intricate in the HMHD simulation. Repetitive development of the twisted magnetic field lines (MFLs) in the vicinity of 3D nulls (reconnection site) is unique to the HMHD evolution of the MFR. The dynamical evolution of magnetic field lines around the reconnection site being affected by the Hall forcing correspondingly affects the large-scale structures.
Switchable dual-broadband to single-broadband terahertz absorber based on hybrid graphene and vanadium dioxide metamaterials
Authors: Hu Dan , Jia Nan , Zhu Qiaofen 
Published: May 2023

Abstract
Switchable and tunable broadband perfect absorbers have drawn great interest in a wide range of applications, including modulation, energy harvesting, and spectroscopy. Here, we propose a switchable and tunable terahertz (THz) metamaterial absorber with dual-broadband, single-broadband perfect absorption using graphene and vanadium dioxide (VO2). Simulation results show that, when VO2 is in the insulated state, this design behaves as a dual-broadband absorber with over 90% absorption in 0.73 THz–1.53 THz and 3.03 THz–3.64 THz under normal incidence. When VO2 is in the metallic state and the graphene Fermi energy is set as 0.01 eV, this design acts as a single-broadband absorber with over 90% absorption in 1.00 THz–3.55 THz and the fractional bandwidth reaches 112%, which is much larger than the previously reported values. The absorption rate can be dynamically tuned by individually changing the conductivity of VO2 and the Fermi energy of graphene. Moreover, this design exhibits polarization-insensitive and wide-incident-angle behaviors for both TE and TM waves. Such a design may have potential applications in many fields, such as thermal detectors, modulators, and stealth technology.
Efficiency improvement of CTL-free PSCs based on Sn-/Pb-perovskite heterojunction: a numerical approach
Authors: Lin Lingyan , Jiang Linqin , Li Ping , Xiong Hao , Yang Aijun , Li Jiansheng , Sun Wen-Hsien , Qiu Yu 
Published: May 2023

Abstract
Perovskite solar cells (PSCs) with no charge transport layer (CTL) have drawn great attentions due to their simple device structure and low cost. However, the low efficiency hampers their practical applications. In the study, a novel FASnI3/MAPbI3 heterojunction structure is proposed to replace the conventional MAPbI3 absorber layer for efficient CTL-free PSCs. The numerical tool SCAPS-1D is employed to optimize the proposed structure taking into account multiple device and material parameters, such as layer thickness, doping concentration of MAPbI3, electron affinity of FASnI3 and back electrode work function. After optimization, the highest yielded efficiency of the FASnI3/MAPbI3 bilayer structure is 25.34%, which is 54.9% relatively higher than the conventional MAPbI3 single-layer structure (with an optimal efficiency of 16.36%). The simulation results demonstrate the huge potentials of proposed FASnI3/MAPbI3 heterojunction for constructing efficient CTL-free PSCs and provide inspirations for the future development of CTL-free PSCs.
Double roton-minima in bosonic fractional quantum Hall states
Authors: Indra Moumita , Jain Deepak , Mondal Sandip 
Published: May 2023

Abstract
We have studied the collective spin-conserving collective excitation spectra in rotating diluted ultra-cold Bose atoms. Double roton-minima have been observed in the fractional quantum Hall (FQH) states for the two filling fractions (ν) of the first series of Jain's composite fermion sequences. The obtained roton-minima for ν = 1/4 are at the wave-vectors 1.26 and 2.38 and the roton-minima for ν = 1/6 have been shifted to 1.08 and 2.06. Such shift of roton-minima is attributed due to strong correlation between the particles in bosonic FQH-system. Moreover, the number of roton minima observed depends upon number of attached fluxes as well as the ranges of interaction between the particles.
Gravitational wave production from preheating with trilinear interactions
Authors: Cosme Catarina , Figueroa Daniel G. , Loayza Nicolás 
Published: May 2023

Abstract
We investigate the production of gravitational waves (GWs) during preheating with
monomial/polynomial inflationary potentials, considering a trilinear coupling ϕχ2 between
a singlet inflaton ϕ and a daughter scalar field χ. For sufficiently large couplings,
the trilinear interaction leads to an exponential production of χ particles and, as a result,
a large stochastic GW background (SGWB) is generated throughout the process. We study the linear
and non-linear dynamics of preheating with lattice simulations, following the production of GWs
through all relevant stages. We find that large couplings lead to SGWBs with amplitudes today that
can reach up to h
2ΩGW
(0) ≃ 5 · 10-9. These backgrounds are however
peaked at high frequencies f
p ≳ 5 · 106 Hz,
which makes them undetectable
by
current/planned GW observatories. As the amount of GWs produced is in any case remarkable, we
discuss the prospects for probing the SGWB indirectly by using constraints on the effective number
of relativistic species in the universe N
eff.
Light nuclei production in Au+Au collisions at
3 GeV from coalescence model*
Authors: Xu Yue , He Xionghong , Xu Nu 
Published: May 2023

Abstract
The nucleon coalescence model is one of the most popular theoretical models for light nuclei production in high-energy heavy-ion collisions. The production of light nuclei d, t,

He, and

He is studied using the transport model JAM with a simplified afterburner coalescence at

GeV Au+Au collisions. We scan the cut-off of phenomenological coalescence parameters, i.e., the relative spatial distance

and momentum difference

, for the formation of light nuclei by nucleon coalescence to reproduce the light nuclei

spectra measured by the STAR experiment. The results indicate a potential connection between the coalescence parameters and the binding energy as well as the diameter of these light nuclei.
Lepton flavor violating decays of vector mesons in the MRSSM*
Authors: Sun Ke-Sheng , Zhang Wen-Hui , Chen Jian-Bin , Zhang Hai-Bin , Yan Qi-geng 
Published: May 2023

Abstract
In this study, we analyze the rare decays of the neutral vector mesons

and

in the scenario of the minimal R-symmetric supersymmetric standard model using the effective Lagrangian method. The predicted branching ratios are dominated by the mass insertion parameters

, i.e., the off-diagonal inputs, and the contributions of different parts are comparable. Taking into account the experimental constraints on the mass insertion parameters, the predicted branching ratios for the most promising processes

are ten orders of magnitude smaller than the present experimental bounds.
Decoding and geometry of ten finger movements in human posterior parietal cortex and motor cortex
Authors: Guan Charles , Aflalo Tyson , Kadlec Kelly , Gámez de Leon Jorge , Rosario Emily R , Bari Ausaf , Pouratian Nader , Andersen Richard A 
Published: May 2023

Abstract

Objective. Enable neural control of individual prosthetic fingers for participants with upper-limb paralysis. Approach. Two tetraplegic participants were each implanted with a 96-channel array in the left posterior parietal cortex (PPC). One of the participants was additionally implanted with a 96-channel array near the hand knob of the left motor cortex (MC). Across tens of sessions, we recorded neural activity while the participants attempted to move individual fingers of the right hand. Offline, we classified attempted finger movements from neural firing rates using linear discriminant analysis with cross-validation. The participants then used the neural classifier online to control individual fingers of a brain–machine interface (BMI). Finally, we characterized the neural representational geometry during individual finger movements of both hands. Main Results. The two participants achieved 86% and 92% online accuracy during BMI control of the contralateral fingers (chance = 17%). Offline, a linear decoder achieved ten-finger decoding accuracies of 70% and 66% using respective PPC recordings and 75% using MC recordings (chance = 10%). In MC and in one PPC array, a factorized code linked corresponding finger movements of the contralateral and ipsilateral hands. Significance. This is the first study to decode both contralateral and ipsilateral finger movements from PPC. Online BMI control of contralateral fingers exceeded that of previous finger BMIs. PPC and MC signals can be used to control individual prosthetic fingers, which may contribute to a hand restoration strategy for people with tetraplegia.
Simultaneous control of safety factor profile and normalized beta for JT-60SA using reinforcement learning
Authors: Wakatsuki T. , Yoshida M. , Narita E. , Suzuki T. , Hayashi N. 
Published: May 2023

Abstract
Plasma with an internal transport barrier (ITB) will be developed in JT-60SA as an attractive operation appropriate for a steady-state fusion reactor. To achieve the ITB plasma while avoiding magnetohydrodynamic instabilities, it is advantageous to simultaneously control the safety factor (q) profile and the normalized beta (

β

N

). In this study, a control system for simultaneous control of the q profile and

β

N

is studied in simulations prior to the real experiment in JT-60SA. The bootstrap current dominates the total current in the ITB region, which results in a coupling between the pressure profile and the q profile. Thus, it is crucial to control the q profile and

β

N

according to the strength of the ITB. A two-stage neural network (NN)-based control system was developed to address this problem. The first stage estimates the transport properties (i.e. ITB strength) of the plasma from measurements. The second stage consists of several NNs for control of the q profile and

β

N

. According to the ITB strength estimated by the NN in the first stage, the appropriate NN for control is selected from those in the second stage. Each NN in the second stage is trained to control plasmas with different ITB strengths through reinforcement learning employing RAPTOR, an integrated transport code. To validate this system, it is tested in a simulation employing another integrated transport code, TOPICS, to mimic the plasma control in JT-60SA plasmas with various ITB strengths. Stable control of the q profile and

β

N

is achieved in ITB plasmas simulated by both the RAPTOR and TOPICS codes.
Analysis of Ignition Test Failure of Solid Rocket Engine
Authors: Gao Shiyuan , Xu Ze , Zhao Tao 
Published: May 2023

Abstract
This paper reviews the ignition failure of a solid rocket engine in a flight test. A fault tree is established to investigate and analyze the causes. After a series of ground tests to reproduce the faults, it is considered that the humidity of the igniter is the main reason affecting the normal ignition of the engine, and follow-up improvement measures are formulated.
Research on the Dynamic Characteristics of a Low Recoil Swing Chamber Gun Based on the Cased Telescoped Ammunition and Rarefaction Wave Gun Technology
Authors: Han Ru-feng , Tang Peng-bo , Wang Yong-cun , Liu Ye , Cao Yong-jie 
Published: May 2023

Abstract
Based on the theory of a low-recoil rarefaction wave(RAVEN)gun firing cased telescoped ammunition(CTA), the equation system of interior ballistics and kinematics also dynamics were established. The dynamic characteristic curves were obtained by numerical simulation analysis, and the results were verified by firing tests. Compared with traditional closed-breech guns, the low recoil force swing chamber gun keeps the projectile’s muzzle velocity basically unchanged, while the maximum recoil is reduced by up to 74%. Based on these results, the parameters of the inertial breech buffer spring were optimized by numerical simulation optimization algorithms which efficiency is faster than using virtual prototyping technology, while the maximum recoil force of the breech reduced by 14.2% without affecting system performance and structural installation size, which effectively improved the overall performance of the weapon system.
Prescribed Performance Control for Electro-hydraulic Servo System of the Ammunition Manipulator
Authors: Nie Shoucheng , Qian Linfang , Xu Lilin 
Published: May 2023

Abstract
There are stochastic initial disturbances which lead to unexpected tracking errors of the ammunition manipulator during the starting stage. In this paper, a prescribed performance control strategy is proposed for the steady constraint control of the ammunition coordinator. In order to keep the position errors of the ammunition coordinator in the whole tracking control process within the prescribed constraint range, the prescribed performance control theory is adopted to convert the system original error into a new error form that can be restrained through error transformation, and the performance function is designed to constrain the error boundary. The second-order command filter is used to reduce the derivation calculation error of the virtual control variables during the backstepping iteration and the corresponding filtering error compensation algorithm is designed to improve the control accuracy. In addition, adaptive laws are well-designed to compensate the uncertainty of system parameters. The simulation analysis shows that the designed prescribed performance controller obtains good control performance. The convergence and stability of the tracking error of the ammunition manipulator are achieved, and the prescribed performance function prevents the violation of tracking error performance constraints.
Fatigue Life Analysis of Balance Elbow Structure During Firing
Authors: Hongying Xu , Jiaxing Li , Jun Liu , bin Gu 
Published: May 2023

Abstract
As a key component of tracked armored vehicle, balance elbow connects vehicle body and road wheel. Balance elbow transmits large amount of impact energy generated by up and down movement of road wheel to torsion bar in order to reduce impact force on vehicle body. Performance of tracked armored vehicle is improved continuously, higher requirements are put forward for design of balance elbow. Fatigue life of balance elbow during firing while tracked armored vehicle is in parking state is calculated by simplified load spectrum method and rain-flow counting method. Difference between fatigue life results is only 3.81%. Simplified load spectrum method can meet certain accuracy requirements. Rain-flow counting method additionally considers other small stress cycles other than maximum stress cycle, which is more accurate for estimation of fatigue life of balance elbow. Considering uncertainty of load under other working conditions in battlefield, load on tracked armored vehicle during firing is increased by 20%-100%. Fatigue life of balance elbow is significantly reduced by 99.99% after load is increased by 100%.Balance elbow has plastic deformation with low-cycle fatigue characteristic. Influence of change of concave-circle`s diameter at root of mounting surface of balance elbow on its fatigue life is studied. Results show that when concave-circle`s diameter at root of mounting surface of balance elbow is 70mm, fatigue life of balance elbow is highest and 133% higher than design state, which provides an idea for optimization of fatigue life of balance elbow structure.
Research on Recoil Resistance Control Technology of Amphibious Vehicle Weapon
Authors: Zhao JK , Ren GW , Yan SJ , Xu XQ 
Published: May 2023

Abstract
In order to improve the water shooting stability of amphibious vehicle weapon, the recoil motion differential equation of vehicle weapon is established by analyzing the force motion of amphibious vehicle during water shooting. the structure of valve-controlled recoil device and the optimal strategy of grey predictive fuzzy control are determined, and the recoil resistance characteristic curves with or without servo valve and different control voltages are analyzed numerically. And the water motion attitude of the amphibious vehicle under different recoil force. The simulation results show that the valve-controlled recoil device has a good recoil damping platform effect. By adjusting the liquid flow channel of the traditional anti-recoil device by using the servo valve, the recoil resistance of the vehicle weapon can be effectively controlled and the water firing stability of the amphibious vehicle weapon can be improved.
A Review on Life Prediction Methods of Gun Barrel
Authors: Zhang L K , Wang K , Pan G H , Wang D S Y 
Published: May 2023

Abstract
In large caliber gun system, the high speed, high temperature and high pressure gas produced by propellant combustion will cause serious erosion damage to the inner wall of barrel, which will lead to continuous decline of gun performance and termination of the maximum life of barrel. The theories and methods of gun barrel life prediction mainly involve thermodynamics, chemistry, material and machinery science and so on. This paper mainly introduces the main mechanism of gun erosion and the calculation model of gun erosion which involves the numerical solution in internal ballistic combustion process, the heat transfer and erosion calculation of gun barrel. In view of the accurate calculation of parameters such as the temperature of gunpowder gas can more accurately reflect the erosion of inner wall of gun barrel, this paper summarizes the calculation methods of the temperature, thermal physical property parameters and convective heat transfer coefficient of high temperature and high pressure gas in gun barrel. In order to determine the erosion wear quantity and study the effect of heat input on the erosion process of inner wall of gun, erosion experiments are usually required. At present, the common erosion experiments mainly include the measurement of erosion quantity with semi-closed explosive device and the change of surface characteristics of gun steel target with laser pulse heating. By analyzing the criterion of barrel life, the establishment method of barrel life prediction model is studied deeply, and the main barrel life prediction model is introduced, which is convenient to guide engineering application.