bluuebunny/crossref_metadata_2025_split huggingface dataset:
Production of linear alkanes via the solid-state hydrogenation of interstellar polyynes
Authors: Fedoseev G. , Li X. , Baratta G. A. , Palumbo M. E. , Chuang K.-J. 
Published: December 2024

Context. Highly unsaturated carbon chains, including polyynes, have been detected in many astronomical regions and planetary systems. With the success of the QUIJOTE survey of the Taurus Molecular Cloud-1 (TMC-1), the community has seen a “boom” in the number of detected carbon chains. On the other hand, the Rosetta mission revealed the release of fully saturated hydrocarbons, C3H8, C4H10, C5H12, and (under specific conditions) C6H14 with C7H16, from the comet 67P/Churyumov-Gerasimenko. The detection of the latter two is attributed to dust-rich events. Similarly, the analysis of samples returned from asteroid Ryugu by Hayabusa2 mission indicates the presence of long saturated aliphatic chains in Ryugu’s organic matter.
Aims. The surface chemistry of unsaturated carbon chains under conditions resembling those of molecular clouds can provide a possible link among these independent observations. However, laboratory-based investigations to validate such a chemistry is still lacking. In the present study, we aim to experimentally verify the formation of fully saturated hydrocarbons by the surface hydrogenation of C2nH2(n > 1) polyynes under ultra-high vacuum conditions at 10 K.
Methods. We undertook a two-step experimental technique. First, a thin layer of C2H2 ice was irradiated by UV-photons (≥121 nm) to achieve a partial conversion of C2H2 into larger polyynes: C4H2 and C6H2. Afterwards, the obtained photoprocessed ice was exposed to H atoms to verify the formation of various saturated hydrocarbons.
Results. In addition to C2H6, which was investigated previously, the formation of larger alkanes, including C4H10 and (tentatively) C6H14, is confirmed by our study. A qualitative analysis of the obtained kinetic data indicates that hydrogenation of HCCH and HCCCCH triple bonds proceeds at comparable rates, given a surface temperature of 10 K. This can occur on the timescales typical for the dark cloud stage. A general pathway resulting in formation of other various aliphatic organic compounds by surface hydrogenation of N- and O-bearing polyynes is also proposed. We also discuss the astrobiological implications and the possibility of identifying alkanes with JWST.
Point defect effects in AlGaN 270-nm light emitting diodes introduced by MeV electron and proton irradiation
Authors: Polyakov A. Y. , Alexanyan L. A. , Schemerov I. V. , Vasilev A. A. , Chernykh A. V. , Ivanov Anton , Talnishnikh Nadezhda , Chernyakov Anton , Zakgeim A. L. , Shmidt N. M. , Lagov P. B. , Doroshkevich A. S. , Isayev R. Sh. , Pavlov Yu. S. , Wan Hsiao-Hsuan , Ren Fan , Pearton S. J. 
Published: December 2024

Point defects were controllably introduced into 270 nm AlGaN Light-Emitting Diodes (LEDs) by 5 MeV electron and 1.1 MeV proton irradiations to examine the effect on electrical and luminescent characteristics. The 5 MeV electron irradiations had only a marginal effect on the charge distribution, current flow, and electroluminescence of LEDs for electron fluences up to 4.5 × 1016 e/cm2 that cause very strong degradation in green, blue, and near-UV LEDs. This lack of changes is attributed to the much higher charge densities in quantum-wells (QWs) and quantum barriers (QBs) of the 270 nm LEDs and to higher bond strength in high Al mole fraction AlGaN layers. By contrast, irradiation with 1.1 MeV protons with a fluence of 1016 p/cm2 leads to more than two orders of magnitude decrease in charge density in the QWs and QBs, a strong increase in the series resistance, and the emergence of deep electron traps near Ec-0.5 eV. The difference is explained by a much higher density of primary defects produced by protons. The observed effects are compared to changes in performance caused by aging after high driving current.
Topology optimization of self-supporting metamaterials for additive manufacturing: a novel framework and validation
Authors: Zheng Ran , Yi Bing , Liu Wenlong , Liu Long , Peng Xiang , Tao Yong 
Published: December 2024

Abstract
Topology optimization (TO) for additive manufacturing (AM) often faces challenges related to overhang structures, increasing build time, material costs, and the need for support structures. This paper proposes a novel framework for designing and manufacturing two- and three-dimensional self-supporting metamaterials that eliminate the requirement for additional support during AM. By integrating an AM filter into the TO process, homogenization methods for evaluating elasticity properties, and a symmetry constraint to ensure connectivity between periodic unit cells, we demonstrate optimized self-supporting metamaterials. Manufacturability is verified through fused deposition modeling, and mechanical compression experiments confirm the performance of the resulting metamaterials. The approach offers a cost-effective and time-efficient solution for fabricating complex metamaterials without auxiliary supports.
Numerical analysis of dipole-induced interactions in casson micropolar ferrofluids: Impacts on fluid flow and heat transfer under external magnetic fields
Authors: Kamran Abid , Azhar Ehtsham , Afaq Harsa 
Published: December 2024

Abstract
This study examines micropolar ferrofluids containing microstructures under the influence of an external magnetic field. The presence of ferroparticles and the magnetic field can lead to the generation of dipoles among these particles, which may significantly affect the fluid flow and heat transfer properties of the ferrofluid. The research utilizes a mathematical framework incorporating the equations of mass, momentum, angular momentum, and energy, alongside Maxwell’s equations of electromagnetism. This framework leads to a system of partial differential equations, which are subsequently converted into ordinary differential equations and solved using the BVP4C numerical method. The results, presented through graphs and tables, demonstrate how variations in physical parameters related to microstructures, dipole interactions, and the Casson fluid model influence fluid flow and heat transfer characteristics. The findings show that the fluid’s skin friction increases with higher micro-rotation and fluid parameters, while it decreases with a stronger magnetic parameter along the plate. The angular velocity of the ferrofluid increases due to the presence of a larger number of microstructures near the wall, which contribute to higher angular velocity gradients.
Analytical study of optical soliton solutions for a (2+1)-nonlinear coupled Konopelchenko-Dubrovsky equation in the tropical and mid-latitude tropospheres
Authors: Hussain Ejaz , Raees Nida , Mahmood Irfan , Malik Sandeep , Ibrahim A. , Saad H.-E M. Musa 
Published: December 2024

Abstract
This research work investigates the analytical soliton solution of $(2+1)$-dimensions of the Konopelchenko-Dubrovsky (KD) equation which depicts the nonlinear waves in mathematical physics with weak dispersion. The $(2+1)$-dimensional KD equation significantly enhances the discipline of atmospheric science by examining the characteristics of nonlinear wave phenomena, elucidating the intricate scattering effects and prolonged range interactions prevalent in tropical and mid-latitude atmospheric regions. This mathematical formulation yields a profound understanding of the interaction between equatorial and mid-latitude Rossby waves, effectively capturing their intricate dynamics and interrelations. We used the newly developed schemes known as the generalized Arnous and the $\exp(-\Theta(\mathcal{G}))$-expansion methods to find the analytical soliton solutions. Consequently, various novel collections of solutions, trigonometric, hyperbolic, rational, and logarithmic solutions, are identified. From these methodologies, we derive the kink and anti-kink soliton solutions. The kink soliton pertains to localized alterations in the curvature, amplitude, and morphology of the wave. This particular category of soliton signifies the existence of a pronounced transition between disparate wave height configurations. To gain a deeper understanding of the physical characteristics of these solutions, we present them with various visual representations such as 3D, 2D, contour, and density graphs. These methods have larger applicability and are useful for the $(2+1)$-dimensional KD equation expressing nonlinear physical models in the realm of nonlinear sciences rather than just the equation itself.
Enhanced stabilization performances of an open quantum battery in a photonic band-gap environment
Authors: Hao Xiang 
Published: December 2024

Abstract
We investigate the stabilization mechanism of open quantum batteries driven by a classical field in the weak or strong system-reservoir coupling regime. A protocol to improve the steady-state energy storage performance is proposed by engineering the spectral density of a band-gap environment which is described as the superposition of two inhomogeneous Lorentzian spectrums with different weights. We find out that the interplay between the battery-environment bound state and the reservoir memory effect plays a crucial role in the stabilization performance against the energy dissipation. The formation of the bound state and the non-Markovian effect will be strengthened by adjusting the weights of the environment spectral density. In the charging process, the classical field contributes to enhancing the steady ergotropy. Moreover, the manipulation of the spectrum weights results in the speedup scheme of carrying out the energy storage due to the existence of bound states. In the self-discharging process, increasing the spectral weight allows the battery to maintain a higher steady ergotropy. These results provide a practical approach to achieving optimal quantum batteries with a better stabilization performance.
GHZ state, spin squeezed state, and spin coherent state for frequency estimation under general Gaussian noises
Authors: Chai Qi , Yang Wen 
Published: December 2024

Abstract
Exploring the quantum advantages of various non-classical quantum states in noisy environments is a central subject in quantum sensing. Here we provide a complete picture for the frequency estimation precision of three important states (the GHZ state, maximal spin squeezed state, and spin coherent state) of a spin-S under both individual dephasing and collective dephasing by general Gaussian noise, ranging from the Markovian limit all over to the extreme non-Markovian limit. It turns out that no matter whether or not the noise is Markovian, the spin coherent state is always worse than the classical scheme under collective dephasing although it is equivalent to the classical scheme under individual dephasing. Moreover, the maximal spin squeezed state always give the best sensing precision (and outperforms the widely studied GHZ state) in all cases. This establish the general advantage of the spin squeezed state for noisy frequency estimation in many quantum sensing platforms.
The FAST Galactic Plane Pulsar Snapshot Survey. VI. The Discovery of 473 New Pulsars*
Authors: Han J. L. , Zhou D. J. , Wang C. , Su W. Q. , Yan Yi , Jing W. C. , Yang Z. L. , Wang P. F. , Wang T. , Xu J. , Cai N. N. , Sun J. H. , Yang Q. L. , Xu R. X. , Wang H. G. , You X. P. 
Published: December 2024

Abstract
The Five-hundred-meter Aperture Spherical radio Telescope (FAST) is the most sensitive telescope at the L-band (1.0–1.5 GHz) and has been used to carry out the FAST Galactic Plane Pulsar Snapshot (GPPS) survey in the last 5 yr. Up to now, the survey has covered one-fourth of the planned areas within ±10∘ from the Galactic plane visible by FAST, and discovered 751 pulsars. After the first publication of the discovery of 201 pulsars and one rotating radio transient (RRAT) in 2021 and 76 RRATs in 2023, here we report the discovery of 473 new pulsars from the FAST GPPS survey, including 137 new millisecond pulsars and 30 new RRATs. We find 34 millisecond pulsars discovered by the GPPS survey which can be timed with a precision better than 3 μs by using FAST 15 minute observations and can be used for pulsar timing arrays. The GPPS survey has discovered eight pulsars with periods greater than 10 s including one with 29.77 s. The integrated profiles of pulsars and individual pulses of RRATs are presented. During the FAST GPPS survey, we also detected previously known pulsars and updated parameters for 52 pulsars. In addition, we discovered two fast radio bursts plus one probable case with high dispersion measures indicating their extragalactic origin.
Research on extraction resistance of the certain automatic gun based on projection pursuit method
Authors: Liu D , Bai C J , Zhang S M , Tang P B , Wang H J , Zhao J Y 
Published: December 2024

Abstract
The extraction resistance is the key factor in restricting the continuous firing of the certain automatic gun automaton. The coupling effects of plastic deformation, contact, friction, thermal expansion and inertia during the extraction process are not easy to analyze the factors affecting the extraction force of automatic gun. Therefore, the problem that excessive extraction resistance in the firing process of automatic guns causes the automaton to slow down or even stop firing, the projection pursuit method is used to quantitatively classify and evaluate the extraction resistance of automatic guns to improve the accuracy and objectivity of the analysis of affecting factors. An evaluation index system of hull extraction resistance of automatic gun was established based on the classification of influencing factors, influencing indicators and characteristic values of influencing indicators. An evaluation model was formed with the characteristic values of influencing indicators of hull extraction resistance as the sample set, and the weights of each influencing index were obtained, which with higher weights were consistent with the key indicators considered in the design process of automatic gun automata. The comprehensive evaluation sequence of the extraction resistance of the certain automatic gun under several design parameters is obtained, and the evaluation results are verified by finite element simulation method, which provides an important reference for the design of automatic gun.
Adaptive-Extended-State-Observer-Based Robust Control of Electrohydraulic Missile Launcher With Disturbances Rejection
Authors: Zhao Gaoyang , Zhu Weilin , Wang Jinyuan , Yao Jianyong , Sun Hui , Zhou Ning 
Published: December 2024

Abstract
In this paper, a disturbance-compensated robust controller was used for electrohydraulic missile launchers with the aim of improving the motion accuracy of the system. In the case of both matched and unmatched disturbances, adaptive extended state observers were employed in order to estimate unmodelled disturbances, external disturbances, and so forth. It was thus resolved to implement a feedforward compensation mechanism in order to counteract the effects of unknown disturbances, based on online estimates of the disturbances with the intention of enhancing the performance of the proposed controller. In addition, in order to address the problems of difficulty in obtaining the differential value of the virtual control law and “Curse of Dimensionality”, an improved first-order sliding-mode differentiator (IFOSMD) was employed. The theoretical analysis demonstrated the stability of the multi-observer and the closed-loop system under the proposed control scheme. The efficacy of the controller was demonstrated through the utilisation of numerical simulations.
Design and simulation analysis of electromagnetic gun feeding and conveying device
Authors: Pei Changgui , Liu Xin , Zhou Xiaozhi 
Published: December 2024

Abstract
The electromagnetic gun is a new type of weapon equipment powered by electric energy. Compared with the traditional artillery, the electromagnetic gun has the obvious advantages of high and controllable initial velocity, no explosive in the bore, and high safety. It is a new concept weapon that will be developed in the future. At present, there are many researches on the launching mechanism of electromagnetic gun, but the related research on the matching ammunition supply system is not yet mature. Therefore, in this paper, aiming at the characteristics of electromagnetic gun without propellant, through the comparison and selection of various ammunition supply system schemes, the ammunition supply scheme of horizontal magazine was determined, and the structural design and strength check were carried out to complete the model of each component and the overall assembly of ammunition supply system. After that, the finite element method was used to check the strength of the sprocket, and the dynamic simulation analysis of the ammunition supply system was carried out, so as to complete the design work of the whole ammunition supply system. This paper provides a certain reference for the development of electromagnetic gun feeding system.
Thermodynamic Modelling and Analysis on Pneumatic Recuperator of Artillery Based on Energy Equation
Authors: Chen Liang , Guangsong Chen , Linfang Qian 
Published: December 2024

Abstract
In order to model recoil motion of artillery elaborately, the pneumatic recuperator was modelled and analyzed by thermodynamic theory, and a recuperator force model based on energy equation was proposed. The thermal power, mechanical power and gas equation of state were considered. Comparison with the classical recuperator force model based on polytropic process, the change of gas state with time is directly considered in this model. The effectiveness of the model was verified based on firing experiment data of a soft recoil artillery, and numerical analysis was carried out based on a normal recoil artillery. The results show that the recuperator force model based on energy equation can describe the hysteretic nonlinear properties of the gas state, and can predict the changes of gas pressure and temperature at the end of firing process relative to the start.
Adaptive Prescribed-Time Nonlinear Control for Chain Magazine
Authors: Li Pengfei , Ma Jiahua , Chen Wei , Hu Jian , Deng Wenxiang , Luo Minzhou , Yang Xiaowei 
Published: December 2024

Abstract
To address the issue of the chain magazine system failing to achieve stability within a specified timeframe during operation and to enhance the precision and robustness of its performance, an adaptive prescribed-time robust controller (APTRC) was designed for position control of the chain magazine. The newly introduced controller enables the system to reach stability within the designated time, regardless of initial conditions, thereby improving the robustness of control system against uncertainties and external disturbances. The stability of the controller itself and the closed-loop system was verified using the Lyapunov stability criterion. Simulation results indicate that the controller achieves the desired performance with high control accuracy under three different load conditions: no load, half load, and full load.
Research on the Impact of Rocket Salvo with Different Launch Spacings on Launch Containers
Authors: Guo Zhangxia , Yang Fengyi , Xie Jingyun 
Published: December 2024

Abstract
In the case of a multiple-launch rocket system firing in salvo, the rocket gas jet with different spacing will have different effects on the launch box. In this paper, the multi-barrel rocket launcher launch box was taken as the research object, and the development process of the double-launched and four-launched rocket gas jet impinging launch box under different spacing was numerically simulated. The results showed that under the double salvo, with the increase of the emission spacing, the speed of the gas jet increased, the degree of mutual interference decreased, and the surface pressure on the launch box gradually decreased. A smaller emission spacing would form a stronger airflow interference. The change trend of the four-shot salvo was similar to that of the double-shot salvo, and the change of the phenomenon is more obvious. This study provides a useful reference for further understanding the salvo law of rocket launcher and provides strong support for improving the performance of rocket launcher.
Comparison Study of 155mm Caliber Howitzer Barrel Rifling Depth
Authors: Yan Lijun , Xu Yaofeng , Zhang Shiquan , Yang Diao , Wang Yan , Lei Xin 
Published: December 2024

Abstract
Rifling depth is a very important parameter of howitzer barrel design, which has great influence on howitzer firing performance and security. At present, there are two types of barrel rifling depth design, which are 1.27mm depth rifling and 2.3mm depth rifling. This paper studies the extrusion stress between top surface of rifling land and bearing band of projectile and the rifling depth of projectile. This paper studies the extrusion stress between top surface of rifling land and bearing band of projectile and rotating driving side force when deep rifling howitzer and shallow rifling howitzer are used. This paper studies the extrusion stress between top surface of rifling land and bearing band of projectile and rotating driving side force when deep rifling howitzer and shallow rifling howitzer fires unguided projectiles and guided projectiles. It can be found by comparison that shallow rifling howitzer does better. It can be found by comparison that shallow rifling howitzer does better that deep rifling howitzer in barrel life and guided projectile firing security. Research of this paper will produce an important meaning to our nation’s next generation howitzer.
Simulation Analysis of Large Caliber Howitzer Barrel Forcing Cone Structure
Authors: Yan Lijun , Xu Yaofeng , Zhang Shiquan , Yang Jianwei , Guo Junhang , Lei Xin 
Published: December 2024

Abstract
Forcing cone, whose function is mainly to accommodate bearing band of projectile, is an important design parameter of howitzer barrel design. Forcing cone’s taper directly influences engraving resistance of projectile and wear of starting part of rifling. So structure design of forcing cone is very important to barrel life. So structure design of forcing cone is very important to barrel life. This paper simulates nine types of forcing cone structure and analysis the results. Based on the simulation results, the best forcing cone scheme is closed. This research will provide support to our nation’s next generation 155mm caliber howitzer.
Research on anti-UAV target allocation based on clustering algorithm
Authors: Chi Zhang , Yongliang Yang , Chun Zhang , Haorui Wang , Xiangang Sun 
Published: December 2024

Abstract
With the rapid development of fixed-wing and rotary-wing small tactical UAVs in recent years, cluster attacks based on small tactical UAVs have become one of the main threats to the current air defense system. In the context of the increasing threat of cluster UAVs to air defense in the future, this paper takes the fight against cluster UAVs as the combat goal and the coordinated air defense combat as the combat means. Through clustering algorithm, a large number of cluster UAVs are divided into combat groups, so as to avoid the time waste in switching when switching fire. After simulation analysis, the algorithm has certain guiding significance in improving the efficiency of anti-cluster UAVs.