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An improved SLAM based on RK-VIF:Vision and inertial information fusion via Runge-Kutta method

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Defence Technology（防务技术） 2023年第3期21卷 133-146页

作者： Jia-shan Cui fang-rui zhang Dong-zhu Feng Cong Li Fei Li Qi-chen Tian School of Aerospace Science and Technology Xidian UniversityXi'an710126China China Academy of Space Technology Xian BranchXi'an710100China China Academy of Launch Vehicle Technology Beijing100076China Aerospace Information Research Institute Chinese Academy of SciencesJinan250100China

Simultaneous Localization and Mapping(SLAM)is the foundation of autonomous navigation for unmanned *** existing SLAM solutions are mainly divided into the visual SLAM(vSLAM)equipped with camera and the lidar SLAM equipped with ***,pure visual SLAM have shortcomings such as low positioning accuracy,the paper proposes a visual-inertial information fusion SLAM based on Runge-Kutta improved ***,the Inertial Measurement Unit(IMU)information between two adjacent keyframes is pre-integrated at the front-end to provide IMU constraints for visual-inertial information *** particular,to improve the accuracy in pre-integration,the paper uses the RungeKutta algorithm instead of Euler integral to calculate the pre-integration value at the next ***,the IMU pre-integration value is used as the initial value of the system state at the current frame *** combine the visual reprojection error and imu pre-integration error to optimize the state variables such as speed and pose,and restore map points’three-dimensional ***,we set a sliding window to optimize map points’coordinates and state *** experimental part is divided into dataset experiment and complex indoor-environment *** results show that compared with pure visual SLAM and the existing visual-inertial fusion SLAM,our method has higher positioning accuracy.

关键词： SLAM Runge Kutta

Enrichment and reconfiguration of titanium-bearing phase in vortex smelting reduction process of vanadium-titanium magnetite

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Journal of Iron and Steel Research(International) 2024年第7期31卷 1582-1589页

作者： Yong-chao Han Zhi-he Dou rui zhang Ting-an zhang Shuai fang Key Laboratory for Ecological Metallurgy of Multimetallic Ores(Ministry of Education) Shenyang 110819LiaoningChina School of Metallurgy Northeastern UniversityShenyang 110819LiaoningChina

To comprehensively utilize the low-iron high-vanadium-titanium magnetite,a new method of vortex smelting reduction of vanadium-titanium magnetite was proposed,and the enrichment and reconstitution regularity of Ti-bearing phases in the slag was investigated through X-ray fluorescence spectrometry,X-ray photoelectron spectroscopy,X-ray diffraction analysis,and optical *** phase diagram revealed that the preferential crystallization of MgTi_(2)O_(5) can be achieved by adjusting the CaO,MgO,and TiO_(2) contents of *** predominant Ti-bearing phases in the slag obtained from the reduction process are MgxTi_(3_x)O_(5)(0≤x≤1)and CaTiO_(3).FeTiO_(3) is present at carbon-iron ratio(CR)=1.3,while MgTi_(2)O4 and TiC are formed at CR=*** enrichment of TiO_(2) in the slag increases first and then decreases as the CR increases,and at CR=1.1,the enrichment of TiO_(2) in the slag reaches 51.3 wt.%.Additionally,the concentrations of MgxTi_(3_x)O_(5)(0≤x≤1)and CaTiO_(3) in the slag,along with the grain width of MgxTi_(3_x)O_(5)(0≤x≤1),decrease with the increase in CR.

关键词： Vanadium-titanium magnetite Vortex smelting reduction Phase reconfiguration TiO_(2)enrichment

Impacts of permafrost degradation on streamflow in the northern Himalayas

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Science China Earth Sciences 2024年第6期67卷 1990-2000页

作者： Linfeng FAN fang JI Xingxing KUANG Zhilin GUO rui zhang Chunmiao ZHENG State Key Laboratory of Mountain Hazards and Engineering Resilience Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu 610299China Yangtze Institute for Conservation and Development Hohai UniversityNanjing 210024China School of Environmental Science and Engineering Southern University of Science and TechnologyShenzhen 518055China Eastern Institute for Advanced Study Ningbo 315200China

The Himalayan water tower provides crucial water resources for *** degradation is deemed to exert important impacts on streamflow in the Himalayan ***,the magnitudes of such impacts remain poorly ***,we established a robust hydrological model that incorporated active layer deepening and ground ice melt for the drainage basin of the largest river in the northern Himalayas-the Yarlung Zangbo River(YZR).We estimated that permafrost degradation led to~0.65 km^(3)/yr decrease in surface runoff and~0.35 km^(3)/yr increase in baseflow and ground ice melt contributed~0.25% to the annual streamflow in the YZR for the period ***“fill-and-spill”mechanism helps explain the seeming contradiction of observed increasing versus decreasing baseflow in different permafrost regions *** propose that the dilution of riverine dissolved organic carbon(DOC)concentrations by baseflow may lead to the riverine DOC hysteresis *** study not only lays solid scientific basis for water resources management in the Himalayas,but also yields new insights into how to interpret measured river discharge and nutrient flux in permafrost regions over the globe.

关键词： Permafrost degradation Hydrology Streamflow Surface runoff Groundwater Himalayas

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Efficient second and third harmonic generation in dual-layer lithium niobate microdisk resonator

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Science China(Physics,Mechanics & Astronomy) 2024年第5期67卷 33-38页

作者： Zhenzhong Hao Xiao Wu Qiang Luo zhang Li rui Ma fang Bo Feng Gao Guoquan zhang Jingjun Xu MOE Key Laboratory of Weak-Light Nonlinear Photonics TEDA Institute of Applied Physics and School of PhysicsNankai UniversityTianjin 300457China

Lithium niobate thin film frequency doubler has extensive applications in the preparation of classical and quantum *** this study,we successfully fabricated microdisk resonators with a quality factor of 2.2×10^(5) in reverse-polarization dual-layer x-cut lithium niobate for the first *** on the modal phase matching condition,efficient second harmonic generation with a record normalized conversion efficiency of~56000%W-1 and cascaded third harmonic generation with an efficiency of~6500%W-2 were obtained in the microdisk *** with the periodically poled lithium niobate microcavity,the complex domain structure preparation processes are *** work provides a scheme for achieving highly efficient second-order nonlinear effects in non-periodically poled microcavities.

关键词： harmonic lithium niobate

Magnetic NiFe_(2)O_(4)@FeNi_(3)core-shell nanospheres derived from FeNi-LDH precursor anchoring on rGO nanosheets for enhanced electromagnetic wave absorption

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Journal of Materials Science & Technology 2024年第4期171卷 101-114页

作者： Kunyao Cao Yuan fang Shuai Wang Yue zhang Jiayue Wen Jun Chen rui Zhao Weidong Xue School of Materials and Energy University of Electronic Science and Technology of ChinaChengdu 610054China

Graphene has been extensively utilized in the domain of electromagnetic wave(EMW)absorption ma-terials because of its excellent electrical ***,the inferior impedance matching per-formance and the single loss mechanism vastly restrict the ***,it’s an effective strat-egy to solve these issues by introducing magnetic ***,layer double hydroxide(LDH)is an appropriate template to obtain magnetic component *** that ferromagnetic met-als such as Fe,Co,Ni,and their corresponding metal oxides are usually treated as magnetic compo-nents which are promising candidates for EMW absorption ***,in this work,a FeNi-layered double hydroxide-reduced graphene oxide(FeNi-LDH-rGO)aerogel was synthesized through a series of processes such as electrostatic self-assembly,hydrothermal,freeze-drying,and *** magnetic NiFe_(2)O_(4)@FeNi_(3)core-shell nanospheres were obtained from FeNi-LDH precursor,anchoring on rGO nanosheets after the annealing ***,the effects of different mass ratios of LDH to GO as well as different annealing temperatures of LDH-rGO aerogel on the EMW absorption prop-erty and impedance matching performance were *** a consequence,the fabricated ultralight 600LDH-rGO 2:1 aerogel shows a broad effective absorption bandwidth(EAB)of 7.04 GHz at a thickness of 2.3 mm with a low filling content of only 6 wt%and a low density of 4.4 mg/cm^(3).In conclusion,the synthetic LDH-rGO aerogels offer an effective strategy for preparing EMW absorption materials that own three-dimensional porous network structure and unique magnetic NiFe_(2)O_(4)@FeNi_(3)core-shell struc-ture nanospheres.

关键词： Electrostatic self-assembly Electromagnetic wave absorption LDH-rGO aerogel Layered double hydroxide Reduced graphene oxide NiFe_(2)O_(4)@FeNi_(3)core-shell structure

Thermal stability improvement and microstructure optimization of high cobalt content Nd-Fe-B magnets via terbium grain boundary diffusion

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Journal of Rare Earths 2024年第8期42卷 1531-1538,I0004页

作者： Jiyuan Xu ruiyang Meng Jing Liu Jiateng zhang rui Han Yikun fang Shengzhi Dong Wei Li Division of Functional Materials Research Central Iron and Steel Research InstituteBeijing100081China

The substitution of Fe by Co in the 2:14:1 phase is an effective method to increase the Curie temperature and enhance the thermal stability of the Nd-Fe-B ***,the accumulation of Co ele ment at the grain boundaries(GBs) changes the GBs from nonmagnetic to ferromagnetic and causes the thinlayer GBs to become rare,In this paper,the method of diffusing Tb element was chosen to improve the microstructure and temperature stability of high-Co *** original sintered Nd_(28.5)Dy_(3)-CO_(x)e_(bal)M_(0.6)B_(i)(x=0,6 wt%,12 wt%;M = Cu,Al,Zr) magnets with different Co contents were diffused with Tb by grain boundary diffusion(GBD).After GBD,high-Co magnets exhibit more continuously distributed thin-layer GBs,and their thermal stability is significantly *** high-Co magnets(x=6 wt%),the absolute value of the temperature coefficient of coercivity decreases from 0.603%/K to0.508%/K in the temperature range of 293-413 K,that of remanence decreases from 0.099%/K to 0.091%/K,and the coercivity increases from 18.44 to 25.04 *** electron microscopy(TEM)characterization reveals that there are both the 1:2 phase and the amorphous phase in the high-Co magnet before and after GBD,EDS elemental analysis shows that Tb element is more likely to preferentially replace the rare earth elements in the 2:14:1 main phase than in the 1:2 phase and the amorphous *** concentration of Tb at the edge of the main phase is much higher than that in the 1:2phase and amorphous phase,which is beneficial to the improvement of the *** preferential replacement of Tb elements at the edge of the 2:14:1 phase and thin-layer GBs with a more continuous distribution are synergistically responsible for improving the thermal stability of high-Co *** study indicates that GBD is an effective method to improve the microstructure and thermal stability of high-Co magnets.

关键词： Nd-Fe-B magnets Coercivity Grain boundary diffusion Thermal stability Micro structure Rare earths

Electrochemical converting ethanol to hydrogen and acetic acid for large scale green hydrogen production

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Nano Research 2024年第3期17卷 1542-1551页

作者： Yufeng zhang Wei Zhu Jinjie fang Zhiyuan Xu Yanrong Xue Jiajing Pei rui Sui Xingdong Wang Xuejiang zhang Zhongbin Zhuang State Key Lab of Organic-Inorganic Composites and Beijing Advanced Innovation Center for Soft Matter Science and Engineering Beijing University of Chemical TechnologyBeijing 100029China Laboratory of Advanced Functional Materials of Nanjing Nanjing Xiaozhuang UniversityNanjing 211171China Beijing Key Laboratory of Energy Environmental Catalysis Beijing University of Chemical TechnologyBeijing 100029China

Electrochemical coupling hydrogen evolution with biomass reforming reaction(named electrochemical hydrogen and chemical cogeneration(EHCC)),which realizes green hydrogen production and chemical upgrading simultaneously,is a promising method to build a carbon-neutral ***,we analyze the EHCC process by considering the market *** ethanol to acetic acid and hydrogen approach is the most feasible for large-scale hydrogen *** develop AuCu nanocatalysts,which can selectively oxidize ethanol to acetic acid(>97%)with high long-term *** isotopic and in-situ infrared experiments reveal that the promoted water dissociation step by alloying contributes to the enhanced activity of the partial oxidation reaction path.A flow-cell electrolyzer equipped with the AuCu anodic catalyst achieves the steady production of hydrogen and acetic acid simultaneously in both high selectivity(>90%),demonstrating the potential scalable application for green hydrogen production with low energy consumption and high profitability.

关键词： selective ethanol electrooxidation gold alloy catalyst electrochemical-coupled hydrogen production market assessment interfacial water activation

Problem-solving model guided by stimulus-organism-response theory:State of mind and coping styles of depressed mothers after cesarean delivery

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World Journal of Psychiatry 2024年第6期14卷 945-953页

作者： rui-fang Yuan Mei-Qin Jiang Juan Li Jing-Jing zhang Department of Gynecology and Obstetrics Jiangyin People's HospitalJiangyin 214400Jiangsu ProvinceChina Department of Gynecology The Fifth People's Hospital of WuxiWuxi 214000Jiangsu ProvinceChina Obstetrics and Gynecology Ward II Jiangnan University Affiliated HospitalWuxi 214131Jiangsu ProvinceChina

BACKGROUND The use of a problem-solving model guided by stimulus-organism-response(SOR)theory for women with postpartum depression after cesarean delivery may inform nursing interventions for women with postpartum *** To explore the state of mind and coping style of women with depression after cesarean delivery guided by SOR *** Eighty postpartum depressed women with cesarean delivery admitted to the hospital between January 2022 and October 2023 were selected and divided into two groups of 40 cases each,according to the random number table *** the control group,the observation group adopted the problem-solving nursing model under SOR *** two groups were consecutively intervened for 12 weeks,and the state of mind,coping styles,and degree of post-partum depression were analyzed at the end of the *** The Edinburgh Postnatal Depression Scale and Hamilton Depression Scale-24-item scores of the observation group were lower than in the control group after care,and the level of improvement in the state of mind was higher than that of the control group(P<0.05).The level of coping with illness in the observation group after care(26.48±3.35)was higher than that in the control group(21.73±3.20),and the level of avoidance(12.04±2.68)and submission(8.14±1.15)was lower than that in the control group(15.75±2.69 and 9.95±1.20),with significant differences(P<0.05).CONCLUSION Adopting the problem-solving nursing model using SOR theory for postpartum depressed mothers after cesarean delivery reduced maternal depression,improved their state of mind,and coping level with illness.

关键词： Stimulus-organism-response theory Problem solving model Cesarean section Postpartum depression

Fully distributed dynamic event-triggered formation-containment tracking for multiagent systems with multiple types of disturbances

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Science China(Information Sciences) 2024年第1期67卷 168-186页

作者： Weihua LI Huaguang zhang Juan zhang rui WANG College of Information Science and Engineering Northeastern University State Key Laboratory of Synthetical Automation for Process Industries Northeastern University

This paper is dedicated to addressing the time-varying output formation-containment tracking(TVOFCT) problem for heterogeneous linear multiagent systems(MASs) with multiple types of disturbances under directed communication *** agents are divided into tracking leaders,formation leaders,and *** the output space,the formation leaders are required to form an expected geometric formation while tracking the tracking leader,and the followers are required to enter the convex hull spanned by formation ***,a disturbance observer is designed to observe the disturbance with deterministic ***,by combining adaptive technology with event-triggered technology,an independent fully distributed dynamic event-triggered(FDDET) compensator is designed to estimate the state of the tracking *** main advantages of this compensator lie in the following three aspects:(1) the adaptive weight does not increase unboundedly;(2) the interval time between events is expanded;(3) the design does not rely on any global *** to the design of this compensator,an independent FDDET convex hull observer is further designed to observe the convex hull spanned by formation ***,based on the designed disturbance observer,compensator,and convex hull observer,the adaptive disturbance rejection control input which can make the MASs achieve TVOFCT is ***,a numerical simulation is provided to clearly verify the validity of the theoretical results.

关键词： formation-containment tracking disturbance rejection multiagent systems fully distributed control dynamic event-triggered control