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Mechanistic insights into stepwise activation of malachite for enhancing surface reactivity and flotation performance

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International Journal of Minerals,Metallurgy and Materials 2024年第10期31卷 2159-2172页

作者： Qicheng Feng Wanming Lu Han Wang Qian Zhang State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization Faculty of Land Resource EngineeringKunming University of Science and Technology Yunnan Key Laboratory of Green Separation and Enrichment of strategic Mineral Resources Kunming University of Science and Technology

Malachite is a common copper oxide mineral that is often enriched using the sulfidization-xanthate flotation ***,the direct sulfidization method cannot yield copper concentrate ***,a new sulfidization flotation process was developed to promote the efficient recovery of *** this study,Cu2+was used as an activator to interact with the sample surface and increase its reaction sites,thereby strengthening the mineral sulfidization process and *** to single copper ion activation, the flotation effect of malachitc significantly increased after stepwise Cu2+*** potential, X-ray photoelectron spectroscopy （XPS）,time-of-flight secondary ion mass spectroscopy （ToF-SIMS）,scanning electron microscopy and energy dispersive spectrometry（SEM-EDS）,and atomic force microscopy （AFM） analysis results indicated that the adsorption of S species was significantly enhanced on the mineral surface due to the increase in active Cu sites after Cu2+stepwise ***,the proportion of active Cu-S species also increased,further improving the reaction between the sample surface and subsequent ***-transform infrared spectroscopy (（FT-IR） and contact angle tests implied that the xanthate species were easily and stably adsorbed onto the mineral surface after Cu2+stepwise activation,thereby improving the hydrophobicity of the mineral ***,the copper sites on the malachite surface after Cu2+stepwise activation promote the reactivity of the mineral surface and enhance sulfidization flotation of malachite.

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Optimization of body configuration and joint-driven attitude stabilization for transformable spacecraft under solar radiation pressure

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Astrodynamics 2024年第1期8卷 47-60页

作者： Yuki Kubo Toshihiro Chujo Institute of space and Astronautical Science Japan Aerospace Exploration AgencyKanagawa252-5210Japan Department of Mechanical engineering Tokyo Institute of TechnologyTokyo152-8550Japan

The solar sail is one of the most promising space exploration systems due to its theoretically infinite specific impulse achieved through solar radiation pressure(SRP).Recently,researchers have proposed“transformable spacecraft”capable of actively reconfiguring their body configurations using actuatable *** spacecraft,if used similarly to solar sails,are expected to significantly enhance orbit and attitude control capabilities owing to their high redundancy in control degrees of ***,controlling them becomes challenging due to their large number of inputs,leading previous researchers to impose strong constraints to limit their potential control *** study focuses on novel attitude control techniques for transformable spacecraft under *** developed two methods,namely,joint angle optimization to obtain arbitrary SRP force and torque,and momentum damping control driven by joint angle *** proposed methods are formulated in a general manner and can be applied to any transformable spacecraft comprising front faces that can predominantly receive the SRP on each *** validity of our proposed method is confirmed through numerical *** study contributes to making most of the high control redundancy of transformable spacecraft without the need for expendable propellants,thus significantly enhancing the orbit and attitude control capabilities.

关键词： solar sail transformable spacecraft attitude-joint coupled motion attitudestabilization

An Efficient Algebraic Solution for Moving Source Localization from Quadruple Hybrid Measurements

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Chinese Journal of Electronics 2022年第2期31卷 255-265页

作者： DING Ting ZHAO Yongsheng ZHAO Yongjun Henan High-Speed Railway Operation and Technological Research Center PLA strategic support force Information engineering university

This paper deals with the 3-D moving source localization using time difference of arrival(TDOA), frequency difference of arrival(FDOA), angle of arrival(AOA) and AOA rate measurements, gathered from a set of spatially distributed receivers. The TDOA,FDOA, AOA and AOA rate measurement equations were firstly established according to the space geometric relationship of the source relative to the receivers. Then an efficient closed-form algorithm for source position and velocity estimation from the quadruple hybrid measurements was proposed. The proposed algorithm converts the nonlinear measurement equations into a linear set of equations, which can then be used to estimate the source position and velocity applying weighted least square(WLS) minimization. In contrast to existing two-stage WLS algorithms, the proposed algorithm does not introduce any nuisance parameters and requires merely onestage, which enables for source localization with the fewest receivers necessary. Theoretical accuracy analysis shows that the proposed algorithm reaches the CramerRao lower bound, and simulation studies corroborate the efficiency and superiority of the proposed algorithm over other algorithms.

关键词： Source localization Time difference of arrival Frequency difference of arrival Angle of arrival Angle rate

Design and calibration of spoke piezoelectric six-dimensional force/torque sensor for space manipulator

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Chinese Journal of Aeronautics 2024年第1期37卷 218-235页

作者： Yingjun LI Guicong WANG Shuai ZHANG Yuanqin ZHOU Hongyu LI Zhenguang QI School of Mechanical engineering University of JinanJinan 250022China

The large manipulator outside the space cabin is a multi-degree of freedom actuator for space *** order to realize the automatic control and flexible operation of the space manipulator,a novel spoke structure piezoelectric six-dimensional force/torque sensor with redundancy ability,high stiffness and good decoupling performance is innovatively *** on the deformation coordination relationship,the redundancy measurement mechanism is *** mathematical models of the sensor with and without branch fault are established *** finite element model is established to verify the feasibility of structure and redundancy measuring principle of the *** on the theoretical analysis and simulation analysis,the prototype of the sensor is *** and dynamic calibration experiments are carried *** actual output voltage signal of the six-dimensional force/torque sensor is collected to establish the equation between the standard input applied load and the actual output voltage *** on ant colony optimized BP algorithm,performance indexes of the sensor with and without branch fault are analyzed *** experimental results show that the spoke piezoelectric sixdimensional force/torque sensor with the eight-point support structure has good accuracy and ***,it has strong decoupling characteristic that can effectively shield the coupling between *** nonlinear errors and maximum interference errors of decoupled data with and without branch faults are less than 1% and 2%,*** natural frequency of the sixdimensional force sensor can reach 2856.45 Hz and has good dynamic *** research content lays a theoretical and experimental foundation for the design,development and application of the new six-dimensional force/torque sensors with ***,it will significantly improve the research level in this field,and provide a strong guarantee for the smoot

关键词： Decoupling algorithm Piezoelectric Redundancy Six-dimensional force/torque sensor space manipulator

Thermal-force control ability under variation of electromagnetic stick structure parameters in RPECT

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Journal of Iron and Steel Research(International) 2024年第1期31卷 224-236页

作者： Ting-song Yang Wen-quan Sun Feng-shan Du An-rui He Quan Yang National engineering Research Center of Advanced Rolling and Intelligent Manufacturing University of Science and Technology BeijingBeijing100083China Institute of engineering and Technology University of Science and Technology BeijingBeijing100083China College of Mechanical engineering Yanshan UniversityQinhuangdao066004HebeiChina

Thermal-force driving of roll profile electromagnetic control technology(RPECT),which can be used to adjust the roll profile,can be affected by the sequential temperature rise between the electromagnetic stick(ES)and electromagnetic control *** to the limited space of ES and induction coil,the cross-sectional area of induction coil can be inevitably affected by changing the size of the ES induction zone,which can further change the energy input under the same electromagnetic parameters,the temperature rising effect and the bulging *** investigate this phenomenon,the effects of the radius of the induction zone on the thermal-force contribution ratio,the heating ability of ES and the temperature distribution were analyzed through an electromagnetic-thermal-structural finite element *** ensure that the results are applicable to RPECT,the thermal energy conversion ability and thermal-force roll crown control ability under different lengths of the induction zone were *** was found that whether the current density regulation mode or the current frequency regulation mode is adopted,the cases with 20 or 25 mm radius of the induction zone have the great thermal energy conversion ability and the good thermal-force roll crown control *** reasonable adjustment of the length of the induction zone can reduce the radius required for the maximum energy efficiency *** with the results of the simulation analysis,the optimization of ES based on the control ability maximization requirement is achieved,which provides the base for the design and configuration of ES in RPECT.

关键词： Roll profile electromagnetic control technology Electromagnetic stick Electromagnetic control roll Induction area Thermal-force driving

Mechanical properties of multi-scale germanium specimens from space solar cells under electron irradiation

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Chinese Journal of Aeronautics 2024年第1期37卷 173-185页

作者： Jian QIU Maliya HEINI Jusha MA Wenjia HAN Xunchun WANG Jun YIN Yan SHI Cunfa GAO State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China School of Chemistry and Civil engineering Shaoguan UniversityShaoguan 512005China Key Laboratory of Functional Materials and Devices for Special Environments of Chinese Academy of Sciences Chinese Academy of SciencesUrumqi 830011China Shanghai Institute of space Power-Sources Shanghai 200245China

During long-term service in space,Gallium Arsenide(GaAs)solar cells are directly exposed to electron irradiation which usually causes a dramatic decrease in their *** the multilayer structure of solar cells,the germanium(Ge)layer occupies the majority of the thickness as the *** to the intrinsic brittleness of semiconductor material,there exist various defects during the preparation and assembly of solar cells,the influences of which tend to be intensified by the irradiation *** this work,first,Ge specimens for mechanical tests were prepared at scales from microscopic to ***,after different doses of electron irradiation,the mechanical properties of the Ge specimens were *** experimental results demonstrate that electron irradiation has an obvious effect on the mechanical property variation of Ge in diverse *** four-point bending test indicates that the elastic modulus,fracture strength,and maximum displacement of the Ge specimens all increase,and reach the maximum value at the irradiation dose of 1×10^(15)e/cm^(2).The micrometer scale cantilever and nanoindentation tests present similar trends for Ge specimens after *** force Microscope(AFM)also observed the change in surface ***,a fitting model was established to characterize the relation between modulus change and electron irradiation dose.

关键词： Electron irradiation Germanium Mechanical properties Multi-scale space solar cells

ESMD-Flow: An Intelligent Flow Forwarding Scheme with Endogenous Security Based on Mimic Defense in space-Air-Ground Integrated Network

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China Communications 2022年第1期19卷 40-51页

作者： Ziyong Li Yuxiang Hu Di Zhu JiangxingWu Yunjie Gu PLA strategic support force Information engineering university Zhengzhou 450002China 61660 Unit of PLA Beijing 100089China

The space-Air-Ground Integrated Network(SAGIN) realizes the integration of space, air,and ground networks, obtaining the global communication ***-Defined Networking(SDN) architecture in SAGIN has become a promising solution to guarantee the Quality of Service(QoS).However, the current routing algorithms mainly focus on the QoS of the service, rarely considering the security requirement of flow. To realize the secure transmission of flows in SAGIN, we propose an intelligent flow forwarding scheme with endogenous security based on Mimic Defense(ESMD-Flow). In this scheme, SDN controller will evaluate the reliability of nodes and links, isolate malicious nodes based on the reliability evaluation value, and adapt multipath routing strategy to ensure that flows are always forwarded along the most reliable multiple paths. In addition, in order to meet the security requirement of flows, we introduce the programming data plane to design a multiprotocol forwarding strategy for realizing the multiprotocol dynamic forwarding of flows. ESMD-Flow can reduce the network attack surface and improve the secure transmission capability of flows by implementing multipath routing and multi-protocol hybrid forwarding mechanism. The extensive simulations demonstrate that ESMD-Flow can significantly improve the average path reliability for routing and increase the difficulty of network eavesdropping while improving the network throughput and reducing the average packet delay.

关键词： space-air-ground integrated network(SAGIN) endogenous security multipath routing multi-protocol forwarding

Asymmetric Loss Based on Image Properties for Deep Learning-Based Image Restoration

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Computers, Materials & Continua 2023年第12期77卷 3367-3386页

作者： Linlin Zhu Yu Han Xiaoqi Xi Zhicun Zhang Mengnan Liu Lei Li Siyu Tan Bin Yan Henan Key Laboratory of Imaging and Intelligent Processing PLA Strategic Support Force Information Engineering UniversityZhengzhou450000China

Deep learning techniques have significantly improved image restoration tasks in recent *** a crucial compo-nent of deep learning,the loss function plays a key role in network optimization and performance ***,the currently prevalent loss functions assign equal weight to each pixel point during loss calculation,which hampers the ability to reflect the roles of different pixel points and fails to exploit the image’s characteristics *** address this issue,this study proposes an asymmetric loss function based on the image and data characteristics of the image recovery *** novel loss function can adjust the weight of the reconstruction loss based on the grey value of different pixel points,thereby effectively optimizing the network training by differentially utilizing the grey information from the original ***,we calculate a weight factor for each pixel point based on its grey value and combine it with the reconstruction loss to create a new loss *** ensures that pixel points with smaller grey values receive greater attention,improving network *** order to verify the effectiveness of the proposed asymmetric loss function,we conducted experimental tests in the image super-resolution *** experimental results show that the model with the introduction of asymmetric loss weights improves all the indexes of the processing results without increasing the training *** the typical super-resolution network SRCNN,by introducing asymmetric weights,it is possible to improve the peak signal-to-noise ratio(PSNR)by up to about 0.5%,the structural similarity index(SSIM)by up to about 0.3%,and reduce the root-mean-square error(RMSE)by up to about 1.7%with essentially no increase in training *** addition,we also further tested the performance of the proposed method in the denoising task to verify the potential applicability of the method in the image restoration task.

关键词： Deep learning image restoration loss function image properties super resolution image denoising

Pattern-reconfigurable antenna-assisted secret key generation from multipath fading channels

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Frontiers of Information Technology & Electronic engineering 2023年第12期24卷 1803-1814页

作者： Zheng WAN Mengyao YAN Kaizhi HUANG Zhou ZHONG Xiaoming XU Yajun CHEN Fan WU PLA strategic support force Information engineering university Zhengzhou450001China Purple Mountain Laboratories for Network and Communication Security Nanjing210096China

Physical layer key generation(PKG)technology leverages reciprocal channel randomness to generate shared secret ***,multipath fading at the receiver may degrade the correlation between legitimate uplink and downlink channels,resulting in a low key generation rate(KGR).In this paper,we propose a PKG scheme based on the pattern-reconfigurable antenna(PRA)to boost the secret key ***,we propose a reconfigurable intelligent surface(RIS)based PRA architecture with the capability of flexible and reconfigurable antenna ***,we present the PRA-based PKG protocol to improve the KGR via mitigation of the effects of multipath ***,a novel algorithm for estimation of the multipath channel parameters is proposed based on atomic norm ***,a novel optimization method for the matching reception of multipath signals is formulated based on the improved binary particle swarm optimization(BPSO)***,simulation results show that the proposed scheme can resist multipath fading and achieve a high KGR compared to existing ***,our findings indicate that the increased degree of freedom of the antenna patterns can significantly increase the secret key capacity.

关键词： Physical layer security Secret key generation Reconfigurable intelligent surface Multipath fading Pattern-reconfigurable antenna