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Staring-imaging satellite pointing estimation based on sequential ISAR images

Chinese Journal of Aeronautics 2024年第8期37卷 261-276页

作者： Canyu WANG Libing JIANG Weijun ZHONG Xiaoyuan ren Zhuang WANG National Key Laboratory of Automatic Target Recognition National University of Defense TechnologyChangsha 410073China Xi’an Satellite Control Center Xi’an 710600China

Pointing estimation for spacecraft using Inverse Synthetic Aperture Radar(ISAR)images plays a significant role in space situational awareness and ***,feature extraction and cross-range scaling of ISAR images create bottlenecks that limit performances of current estimation ***,the emergence of staring imaging satellites,characterized by complex kinematic behaviors,presents a novel challenge to this *** address these issues,this article proposes a pointing estimation method based on Convolutional Neural Networks(CNNs)and a numerical optimization algorithm.A satellite’s main axis,which is extracted from ISAR images by a proposed Semantic Axis Region Regression Net(SARRN),is chosen for investigation in this article due to its unique ***,considering the kinematic characteristic of the staring satellite,an ISAR imaging model is established to bridge the target pointing and the extracted *** on the imaging model,pointing estimation and cross-range scaling can be described as a maximum likelihood estimation problem,and an iterative optimization algorithm modified by using the strategy of random sampling-consistency check and weighted least squares is proposed to solve this ***,the pointing of targets and the cross-range scaling factors of ISAR images are *** experiments based on actual satellite orbital parameters verify the effectiveness of the proposed *** work can improve the performance of satellite reconnaissance warning,while accurate cross-range scaling can provide a basis for subsequent data processes such as 3D reconstruction and attitude estimation.

关键词： Staring-imaging Agile satellite Inverse Synthetic Aperture Radar(ISAR) Pointing estimation Cross-range scaling

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Integral precession calibration method of PIGA on linear vibration table

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Chinese Journal of Aeronautics 2024年第3期37卷 219-236页

作者： Chuang SUN Shun-qing ren Jun-wei CAO Ru HUO Department of Automation Tsinghua UniversityBeijing 100084China School of Astronautics Harbin Institute of TechnologyHarbin 150001China Beijing National Research Center for Information Science and Technology Tsinghua UniversityBeijing 100084China Faculty of Information technology Beijing University of TechnologyBeijing 100124China

Linear vibration table can provide harmonic accelerations to excite the nonlinear error terms of Pendulous Integrating Gyro Accelerometer(PIGA).Integral precession calibration method is proposed to calibrate PIGA on a linear vibration table in this *** on the precise expressions of PIGA’s inputs,the error calibration model of PIGA is *** angular velocity errors of PIGA are suppressed by integer periodic precession and the errors caused by non-integer periods vibrating are *** complete calibration process,including planning,preparation,PIGA testing,and coefficient identification,is designed to optimize the test operations and evaluate the calibration *** effect of the main errors on calibration uncertainty is analyzed and the relative sensitivity function is proposed to further optimize the test *** and simulation results verify that the proposed 10-position calibration method can improve calibration uncertainties after compensating for the related *** order of calibration uncertainties of the second-and third-order coefficients are decreased to 10^(-8)(rad.s^(-1))/g^(2)and 10^(-8)(rad.s^(-1))/g3,*** with the other two classical calibration methods,the calibration uncertainties of PIGA’s nonlinear error coefficients can be effectively reduced and the proportional residual errors are decreased less than 3×10-6(rad.s^(-1))/g by using the proposed calibration method.

关键词： PIGA Linear vibration table Vibration measurement Calibration Error analysis Uncertainty analysis

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Design and optimization of a greener sinomenine hydrochloride preparation process considering variations among different batches of the medicinal herb

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Chinese Journal of Chemical Engineering 2024年第7期71卷 77-90页

作者： Dandan ren Jiale Xie Tianle Chen Haibin Qu Xingchu Gong Pharmaceutical Informatics Institute College of Pharmaceutical SciencesZhejiang UniversityHangzhou 310058China National Key Laboratory of Chinese Medicine Modernization Zhejiang UniversityHangzhou 310058China Jinhua Institute of Zhejiang University Jinhua 321016China

The current methods used to industrially produce sinomenine hydrochloride involve several issues,including high solvent toxicity,long process flow,and low atomic utilization efficiency,and the greenness scores of the processes are below 65 *** solve these problems,a new process using anisole as the extractant was *** exhibits high selectivity for sinomenine and can be connected to the subsequent water-washing *** alkalization of the medicinal material,heating extraction,water washing,and acidification crystallization were carried *** process was modeled and *** design space was *** recommended operating ranges for the critical process parameters were 3.0–4.0 h for alkalization time,60.0–80.0℃ for extraction temperature,2.0–3.0(volume ratio)for washing solution amount,and 2.0–2.4 mol·L^(-1) for hydrochloric acid *** new process shows good robustness because different batches of medicinal materials did not greatly impact crystal purity or sinomenine transfer *** sinomenine transfer rate was about 20%higher than that of industrial *** greenness score increased to 90 points since the novel process proposed in this research solves the problems of long process flow,high solvent toxicity,and poor atomic economy,better aligning with the concept of green chemistry.

关键词： Sinomenine hydrochloride Process optimization Anisole

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Graphene enables equiatomic FeNiCrCoCu high-entropy alloy with improved TWIP and TRIP effects under shock compression

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Journal of Materials Science & Technology 2024年第3期170卷 186-199页

作者： Hongcai Xie Zhichao Ma Wei Zhang Hongwei Zhao Luquan ren School of Mechanical and Aerospace Engineering Jilin UniversityChangchun 130025China Key Laboratory of CNC Equipment Reliability Ministry of Education Jilin UniversityChangchun 130025China Key Laboratory of Bionic Engineering Ministry of Education Jilin UniversityChangchun 130025China Weihai Institute for Bionics-Jilin University Weihai 264400China Institute of Structured and Architected Materials Liaoning Academy of MaterialsShenyang 110167China

Graphene(Gr)reinforced high-entropy alloy(HEA)matrix composites are expected as potential candidates for next-generation structural applications in light of outstanding mechanical properties.A deep comprehension of the underlying deformation mechanisms under extreme shock loading is of paramount importance,however,remains lacking due to experimentally technical limitations in *** the present study,by means of nonequilibrium molecular dynamics simulations,dynamic deformation behaviors and corresponding mechanisms in equiatomic FeNiCrCoCu HEA/Gr composite systems were investigated in terms of various shock *** resistance to dislocation propagation imparted by Gr was corroborated to encourage the elevated local stress level by increasing the likelihood of dislocation interplays,which facilitated the onset of twins and hexagonal close-packed(HCP)martensite ***,the advent of Gr was demonstrated to endow the HEA with an additional twinning pathway that induced a structural conversion from HCP to parent face-centered cubic(FCC)inside HCP martensite laths,different from the classical one that necessitated undergoing the intermediate procedure of extrinsic stacking fault(ESF)*** than that,by virtue of an increase in flow stress,the transformation-induced plasticity(TRIP)effect was validated to be additionally evoked as the predominant strain accommodation mechanism at higher strains on the one hand,but which only assisted plasticity in pure systems,and on the other hand,can also act as an auxiliary regulation mode together with the twinning-induced plasticity(TWIP)effect under intermediate strains,but with enhanced contributions relative to pure *** may expect that TRIP and TWIP effects promoted by introducing Gr would considerably inspire a synergistic effect between strength and ductility,contributing to the exceptional shock-resistant performance of FeNiCrCoCu HEAs under extreme regimes.

关键词： Molecular dynamics High-entropy alloy Graphene TRIP TWIP Shock

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Resource utilization of drinking water treatment aluminum sludge in green cementing materials: Hydration characteristics and hydration kinetics

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Journal of Environmental Sciences 2024年第10期144卷 236-248页

作者： Jing Yang Cheng Chen Shuoyu Chen Yujie ren Jinsuo Lu School of Environmental and Municipal Engineering Xi’an University of Architecture and TechnologyXi’an 710055China

As a byproduct of water treatment,drinking water treatment aluminum sludge(DWTAS)has challenges related to imperfect treatment and disposal,which has caused potential harm to human health and the *** this paper,heat treatment DWTAS as a supplement cementitious material was used to prepare a green cementing *** results show that the 800℃ is considered as the optimum heat treatment temperature for ***-800℃ is fully activated after thermal decomposition to form incompletely crystallized highly activeγ-Al2O3 and active SiO_(2).The addition of DWTAS promoted the formation of ettringite and C-(A)-S-H gel,which could make up for the low early compressive strength of cementing materials to a certain *** cured for 90 days,the compressive strength of the mortar with 30% DWTAS-800℃ reached 44.86 *** dynamic process was well simulated by Krstulovi′c-Dabi′c hydration kinetics *** study provided a methodology for the fabrication of environmentally friendly and cost-effective compound cementitiousmaterials and proposed a“waste-to-resource”strategy for the sustainable management of typical solid wastes.

关键词： Drinking water treatment aluminum sludge Green cementing material Hydration characteristics Hydration kinetics

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Copper-Free Resin-Based Braking Materials:A New Approach for Substituting Copper with Fly-Ash Cenospheres in Composites

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Chinese Journal of Mechanical Engineering 2024年第2期37卷 401-412页

作者： Kaikui Zheng Youxi Lin Shanmin You Zhiying ren Jianmeng Huang School of Mechanical Engineering and Automation Fuzhou UniversityFuzhou 350108China National United Engineering Laboratory for Advanced Bearing Tribology Henan University of Science and TechnologyLuoyang 471023China

Copper particles emitted from braking have become a significant source of environmental ***,copper plays a crucial role in resin-based braking *** high-performance braking materials without copper has become a significant *** this paper,the resin-based braking materials were filled with flyash cenospheres to develop copper-free braking *** effects of fly-ash cenospheres on the physical properties,mechanical and friction and wear properties of braking materials were ***,the wear mechanism of copper-free resin-based braking materials filled with fly-ash cenospheres was *** results indicate that the inclusion of fly-ash cenospheres in the braking materials improved their thermal stability,hardness and impact strength,reduced their density,effectively increased the friction coefficient at medium and high temperatures,and enhanced the heat-fade resistance of the braking *** inclusion of fly-ash cenospheres contributed to the formation of surface friction film during the friction process of the braking materials,and facilitated the transition of form from abrasive wear to adhesive *** 100-350℃,the friction coefficient of the optimal formulation is in the range of 0.57-0.61,and the wear rate is in the range(0.29-0.65)×10^(-7) cm^(3)·N^(-1)·m^(-1),demonstrating excellent resistance to heat-fade and stability in friction *** research proposes the use of fly-ash cenospheres as a substitute for environmentally harmful and expensive copper in brake materials,which not only improves the performance of braking materials but also reduces their costs.

关键词： Fly-ash cenospheres Braking materials Friction and wear Heat-fade resistance Wear form

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Visible Light Indoor Positioning System Based on Pisarenko Harmonic Decomposition and Neural Network

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Chinese Journal of Electronics 2024年第1期33卷 195-203页

作者： Li ZHAO Yi ren Qi WANG Lange DENG Feng ZHANG School of Electronic Information Engineering Xi’an Technological University

Visible-light indoor positioning is a new generation of positioning technology that can be integrated into smart lighting and optical communications. The current received signal strength(RSS)-based visible-light positioning systems struggle to overcome the interferences of background and indoor-reflected noise. Meanwhile, when ensuring the lighting, it is impossible to use the superposition of each light source to accurately distinguish light source information; furthermore, it is difficult to achieve accurate positioning in complex indoor environments. This study proposes an indoor positioning method based on a combination of power spectral density detection and a neural network. The system integrates the mechanism for visible-light radiation detection with RSS theory, to build a back propagation neural network model fitting for multiple reflection channels. Different frequency signals are loaded to different light sources at the beacon end, and the characteristic frequency and power vectors are obtained at the location end using the Pisarenko harmonic decomposition method. Then, a complete fingerprint database is established to train the neural network model and conduct location tests. Finally, the location effectiveness of the proposed algorithm is verified via actual positioning experiments. The simulation results show that, when four groups of sinusoidal waves with different frequencies are superimposed with white noise, the maximum frequency error is 0.104 Hz and the maximum power error is 0.0362 W. For the measured positioning stage, a 0.8 m × 0.8 m × 0.8 m solid wood stereoscopic positioning model is constructed, and the average error is 4.28 cm. This study provides an effective method for separating multi-source signal energies, overcoming background noise, and improving indoor visible-light positioning accuracies.

关键词： Neural networks Measurement uncertainty Position measurement Harmonic analysis Light emitting diodes Frequency estimation Indoor positioning systems

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Rapid Energy Exchange between In Situ Formed Bromine Vacancies and CO_(2)Molecules Enhances CO_(2)Photoreduction

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Research 2024年第2期2023卷 763-771页

作者： Qin ren Ye He Hong Wang Yanjuan Sun Fan Dong Research Center for Environmental and Energy Catalysis Institute of Fundamental and Frontier SciencesUniversity of Electronic Science and Technology of ChinaChengdu 611731China School of Resources and Environment University of Electronic Science and Technology of ChinaChengdu 611731China

Photocatalytic reduction of CO_(2)into fuels provides a prospective tactic for regulating the global carbon balance utilizing renewable solar ***,CO_(2)molecules are difficult to activate and reduce due to the thermodynamic stability and chemical *** this work,we develop a novel strategy to promote the adsorption and activation of CO_(2)molecules via the rapid energy exchange between the photoinduced Br vacancies and CO_(2)*** in situ continuous wave-electron paramagnetic resonance(cw-EPR)and pulsed EPR technologies,we observe that the spin-spin relaxation time(T_(2))of BiOBr is decreased by 198 ns during the CO_(2)photoreduction reaction,which is further confirmed by the broadened EPR *** result reveals that there is an energy exchange interaction between in situ formed Br vacancies and CO_(2)molecules,which promotes the formation of high-energy CO_(2)molecules to facilitate the subsequent reduction *** addition,theoretical calculations indicate that the bended CO_(2)adsorption configuration on the surface of BiOBr with Br vacancies caused the decrease of the lowest unoccupied molecular orbital of the CO_(2)molecule,which makes it easier for CO_(2)molecules to acquire electrons and get *** situ diffuse reflectance infrared Fourier transform spectroscopy further shows that the activated CO_(2)molecules are favorably converted to key intermediates of COOH*,resulting in a CO generation rate of 9.1μmol g^(-1)h^(-1)and a selectivity of 100%.This study elucidates the underlying mechanism of CO_(2)activation at active sites and deepens the understanding of CO_(2)photoreduction reaction.

关键词： reaction. adsorption activation

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Can soil organic carbon sequestration and the carbon management index be improved by changing the film mulching methods in the semiarid region?

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Journal of Integrative Agriculture 2024年第5期23卷 1541-1556页

作者： Jialin Yang Liangqi ren Nanhai Zhang Enke Liu Shikun Sun Xiaolong ren Zhikuan Jia Ting Wei Peng Zhang College of Agronomy Northwest A&F UniversityYangling 712100China Key Laboratory of Crop Physi-Ecology and Tillage Science in Northwestern Loess Plateau Ministry of Agriculture and Rural AfairsNorthwest A&FUniversityYangling 712100China Institute of Environment and Sustainable Development in Agriculture Chinese Academy of Agricultural SciencesBeijing 100081China College of Water Resources and Architectural Engineering Northwest A&F UniversityYangling 712100China

Plastic film mulching has been widely used to increase maize yield in the semiarid area of ***, whether long-term plastic film mulching is conducive to agricultural sustainability in this region remains controversial.A field experiment was initiated in 2013 with five different film mulching methods:(i) control method, flat planting without mulching (CK),(ii) flat planting with half film mulching (P),(iii) film mulching on ridges and planting in narrow furrows(S),(iv) full film mulching on double ridges (D), and (v) film mulching on ridges and planting in wide furrows (R).The effects on soil organic carbon (SOC) content, storage, and fractions, and on the carbon management index (CMI)were evaluated after nine consecutive years of plastic film *** results showed that long-term plastic film mulching generally maintained the initial SOC *** with no mulching, plastic film mulching increased the average crop yield, biomass yield, and root biomass by 48.38, 35.06, and 37.32%, respectively, which led to the improvement of SOC ***, plastic film mulching significantly improved CMI, and increased the SOC content by 13.59%, SOC storage by 7.47%and easily oxidizable organic carbon (EOC) by 13.78%on average,but it reduced the other labile *** sequestration and CMI were improved by refining the plastic film mulching *** S treatment had the best effect among the four mulching methods, so it can be used as a reasonable film mulching method for sustainable agricultural development in the semiarid area.

关键词： plastic film mulching soil organic carbon labile organic carbon fractions semiarid area

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水稻醇溶蛋白总含量的多态性分析

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中国粮油学报 2007年第1期22卷 5-8页

作者：蒋冬花黄大年任不凡毛建卫魏兴华浙江新安化工集团有限公司中国水稻研究所国家水稻生物学重点实验室杭州310006 浙江科技学院生物与化学工程系杭州310012

用醇溶蛋白提取剂提取了300个水稻品系的醇溶蛋白，紫外吸收法测定了水稻种子中醇溶蛋白的总含量。发现水稻醇溶蛋白的总含量存在着较大的多态性。大部分水稻品系醇溶蛋白总含量在2—6mg／g这个范围，占所测水稻品系总数的72．0％；醇... 详细信息

用醇溶蛋白提取剂提取了300个水稻品系的醇溶蛋白，紫外吸收法测定了水稻种子中醇溶蛋白的总含量。发现水稻醇溶蛋白的总含量存在着较大的多态性。大部分水稻品系醇溶蛋白总含量在2—6mg／g这个范围，占所测水稻品系总数的72．0％；醇溶蛋白总含量在16mg／g以上的水稻品系很少，占所测水稻品系总数的1．0％；醇溶蛋白含量最高的为来自台湾的编号为T-9598的品系，总含量达23．73mg／g；含量最低的是来自古巴（Cuba）的编号为C-5360的品系，总含量仅为0．35mg／g。本研究有助于筛选醇溶蛋白含量高的水稻品系，也可为水稻醇溶蛋白多态性研究提供科学依据。

关键词：水稻醇溶蛋白多态性紫外吸收法

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