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Deep reinforcement learning based active surge control for aeroengine compressors

Chinese Journal of Aeronautics 2024年第7期37卷 418-438页

作者： Xinglong ZHANG Zhonglin LIN runmin JI Tianhong ZHANG College of Energy and Power Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China School of Mechanical Engineering and Automation Fuzhou UniversityFuzhou 350108China

This study proposes an active surge control method based on deep reinforcement learning to ensure the stability of compressors when adhering to the pressure rise command across the wide operating range of an ***,the study establishes the compressor dynamic model with uncertainties,disturbances,and Close-Coupled Valve(CCV)actuator *** upon this foundation,a Partially Observable Markov Decision Process(POMDP)is defined to facilitate active surge *** address the issue of unobservability,a nonlinear state observer is designed using a finite-time high-order sliding ***,an Improved Soft Actor-Critic(ISAC)algorithm is developed,incorporating prioritized experience replay and adaptive temperature parameter techniques,to strike a balance between exploration and convergence during *** addition,reasonable observation variables,error-segmented reward functions,and random initialization of model parameters are employed to enhance the robustness and generalization ***,to assess the effectiveness of the proposed method,numerical simulations are conducted,and it is compared with the fuzzy adaptive backstepping method and Second-Order Sliding Mode Control(SOSMC)*** simulation results demonstrate that the deep reinforcement learning based controller outperforms other methods in both tracking accuracy and ***,the proposed active surge controller can effectively ensure stable operation of compressors in the high-pressure-ratio and high-efficiency region.

关键词： Aeroengine surge Active surge control Moore-Greitzer model Deep reinforcement learning Soft actor-critic Nonlinear observer

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Field stabilization of pulse duration in a hundredfemtosecond level

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CHINESE OPTICS LETTERS 2024年第8期22卷 081406-081406页

作者： Liu, runmin Wu, Yong Pu, Guoqing Cheng, Jiayang Mu, Huan Liu, Bowen Yi, Lilin Hu, Minglie Tianjin Univ Sch Precis Instruments & Optoelect Engn Key Lab Optoelect Informat Sci & Technol Minist EducUltrafast Laser Lab Tianjin 300072 Peoples R China Shanghai Jiao Tong Univ Sch Elect Informat & Elect Engn State Key Lab Adv Commun Syst & Networks Shanghai 200240 Peoples R China AIOPTICS Co Ltd R&D Ctr Shanghai 200240 Peoples R China

Pulse duration is considered as one of the most important characteristics of high-power femtosecond lasers. However, pulses output from the laser system are susceptible to ambient changes and manifest the instability of pulse durations in an open environment. In this paper, incorporating the algorithmic framework of the improved stochastic hill-climbing search and incremental proportional-integral controller, temperature-induced fluctuations of pulse duration can be effectively compensated by an automatic feedback control in an all-fiber chirped-pulse amplification system. In the experiment, sub-hundred femtosecond fluctuation of pulse duration is introduced to verify the performance robustness of the proposed pulse-duration feedback control (PDFC). The stability of pulse duration is obviously higher than the case without the feedback control, and the peak-to-peak fluctuation of pulse duration is reduced to 6.5%. Furthermore, the robust switching between different pulse durations proves the versatility of the PDFC. We expect that the proposed feedback control method could provide a novel insight into high-power femtosecond lasers widely applied in fundamental researches and industrial fields.

关键词： fiber amplifier femtosecond laser pulse-duration feedback control LASER AMPLIFICATION

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Cancer Cell：我国科学家有望开发出治疗急性髓性白血病的新疗法

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现代生物医学进展 2017年第6期17卷 I0001-I0002页

作者： Chen, Wen-Lian Wang, Yue-Ying Zhao, Aihua Xia, Li Xie, Guoxiang Su, Mingming Zhao, Linjing Liu, Jiajian Qu, Chun wei, runmin Rajani, Cynthia Ni, Yan Cheng, Zhen Chen, Zhu Chen, Sai-Juan Jia, wei Shanghai Jiao Tong Univ Sch Med State Key Lab Med Genom Dept HematolShanghai Inst HematolRui Jin Hosp Shanghai 200025 Peoples R China Shanghai Jiao Tong Univ Affiliated Peoples Hosp 6 Ctr Translat Med Shanghai 200233 Peoples R China Univ Hawaii Ctr Canc Honolulu HI 96813 USA Stanford Univ Sch Med Mol Imaging Program Stanford Dept Radiol Stanford CA 94305 USA Stanford Univ BioX Program Canary Ctr Stanford Canc Early Detect Stanford CA 94305 USA

近日，刊登在国际杂志Cancer Cell上的一项研究报告中，来自上海交通大学医学院等机构的研究人员通过研究发现了治疗急性髓性白血病（AML）的新型治疗靶点和新型疗法，急性髓性白血病是一种血液骨髓癌症，通常需要及时且积极的疗法对这... 详细信息

近日，刊登在国际杂志Cancer Cell上的一项研究报告中，来自上海交通大学医学院等机构的研究人员通过研究发现了治疗急性髓性白血病（AML）的新型治疗靶点和新型疗法，急性髓性白血病是一种血液骨髓癌症，通常需要及时且积极的疗法对这种癌症进行治疗。

关键词： Cell 白血病治疗疗法急性科学家开发上海交通大学

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A low-frequency and broadband wave-insulating vibration isolator based on plate-shaped metastructures

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Applied Mathematics and Mechanics(English Edition) 2024年第7期45卷 1171-1188页

作者： wei wei Feng GUAN Xin FANG College of Intelligent Science National University of Defense TechnologyChangsha410073China Naval Research Academy Beijing100161China

A metamaterial vibration isolator,termed as wave-insulating isolator,is proposed,which preserves enough load-bearing capability and offers ultra-low and broad bandgaps for greatly enhanced wave *** consists of plate-shaped metacells,whose symmetric and antisymmetric local resonant modes offer several low and broad mode bandgaps although the complete bandgap remains high and *** bandgap mechanisms,vibration isolation properties,effects of key parameters,and robustness to complex conditions are *** experimentally demonstrated,the wave-insulating isolator can improve the vibration insulation in the ranges of[50 Hz,180 Hz]and[260 Hz,400 Hz]by 15 dB and 25 dB,respectively,in contrast to the conventional isolator with the same first resonant frequency.

关键词： metamaterial and metastructure vibration isolation bandgap wave insulation plate

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Planet wind: Planetary evolution dominated by electromagnetic forces

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Science China Earth Sciences 2024年第10期67卷 3331-3336页

作者： Yong wei Key Laboratory of Earth and Planetary Physics Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China

1. Introduction Over the five centuries since Copernicus, the focus of planetary science has transitioned from the visible realm to the invisible. In the more than 60 years following the advent of the space age, our a... 详细信息

关键词： evolution dominated planetary

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The lithology and composition of lunar mantle modified by ilmenite bearing cumulate:A thermodynamic model

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Acta Geochimica 2024年第5期43卷 856-875页

作者： wei Huang wei Du State Key Laboratory of Ore Deposit Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China University of Chinese Academy of Sciences Beijing 100049China Center for Excellence in Comparative Planetology Chinese Academy of SciencesHefei 230026China

Due to their high density,the ilmenite-bearing cumulates(IBC)(with or without KREEP)formed during the late-stage lunar magma ocean solidification are thought to sink into the underlying lunar mantle and trigger lunar mantle *** evidence implied that IBC may descend deep inside the Moon and remain as a partially molten layer at the core-mantle boundary(CMB).However,partial melting may have occurred on the mixed mantle cumulates during the sinking of IBC/KREEP and the silicate melt may be positively buoyant,thus preventing the IBC/KREEP layer from sinking to the ***,we perform thermodynamic simulation on the stability of lunar mantle cumulates at different depths mixed with different amounts of IBC/KREEP from an updated LMO *** modeling results suggest that the sinking of IBC/KREEP will cause at least 5 wt%partial melting in the shallow(~120 km)and a much larger degree of partial melting in the deep lunar mantle(~420 km).Due to the density contrast with the surrounding mantle,IBC/KREEP-bearing melts could potentially decouple under certain *** modified lunar mantle by sinking of IBC/KREEP can better explain the formation of different kinds of lunar basaltic magma than the primary lunar mantle formed through differentiation of lunar magma *** of IBC/KREEP back into the lunar mantle may introduce plagioclase,clinopyroxene,garnet,and incompatible radioactive elements into the deep lunar mantle,which will further affect the thermal and chemical evolution of the lunar interior.

关键词： Ilmenite-bearing cumulate KREEP Partial melting Lunar mantle overturn pMELTS

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Task-specific Part Discovery for Fine-grained Few-shot Classification

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Machine Intelligence Research 2024年第5期21卷 954-965页

作者： Yongxian wei Xiu-Shen wei School of Computer Science and Technology Nanjing University of Science and TechnologyNanjing210094China

Localizing discriminative object parts(e.g.,bird head)is crucial for fine-grained classification tasks,especially for the more challenging fine-grained few-shot *** work always relies on the learned object parts in a unified manner,where they attend the same object parts(even with common attention weights)for different few-shot episodic *** this paper,we propose that it should adaptively capture the task-specific object parts that require attention for each few-shot task,since the parts that can distinguish different tasks are naturally *** for a few-shot task,after obtaining part-level deep features,we learn a task-specific part-based dictionary for both aligning and reweighting part features in an ***,part-level categorical prototypes are generated based on the part features of support data,which are later employed by calculating distances to classify query data for *** retain the discriminative ability of the part-level representations(i.e.,part features and part prototypes),we design an optimal transport solution that also utilizes query data in a transductive way to optimize the aforementioned distance calculation for the final *** experiments on five fine-grained benchmarks show the superiority of our method,especially for the 1-shot setting,gaining 0.12%,8.56%and 5.87%improvements over state-of-the-art methods on CUB,Stanford Dogs,and Stanford Cars,respectively.

关键词： Fine-grained image recognition few-shot learning transductive learning visual dictionary part feature discovery

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Humic acid-mediated transport of a typical soil passivation remediation product(chloropyromorphite)in saturated porous media

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Journal of Environmental Sciences 2024年第7期141卷 51-62页

作者： Xinying Li Mengjia Zhang Siyuan Li wei wei School of Environment Jiangsu Engineering Lab of Water and Soil Eco-remediationJiangsu Province Engineering Research Center of Environmental Risk Prevention and Emergency Response TechnologyNanjing Normal UniversityNanjing 210023China Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application Nanjing 210023China

Conversion of labile Pb species into chloropyromorphite(CPY)using phosphorus-bearing amendments was considered to be an ideal strategy in soil passivation ***,the fate and transport of CPY in the soil are poorly *** study aims to fill the knowledge gap by evaluating the fate and transport of CPY under environmentally relevant conditions of humic acid(HA),pH,electrolyte concentration,and species through the saturated sandy *** showed that bare CPY colloids are basically immobile in sandy porous media while the co-existence of HA made the transport of CPY improved by30%-93.5%.Facilitated transport of CPY was attributed to the increased stability of CPY and the repulsive interaction between CPY particles and sands due to HA *** mobility of CPY was also increased with increasing pH from 5.0 to *** the pH was 9 with a10 mmol/L NaCl background solution,the stronger energy barrier between CPY and sand led to enhanced transport *** divalent Ca^(2+)had a more dramatic effect than monovalent Na^(+)on the aggregation and sedimentation of CPY colloids due to its effectivescreening of the surface charge of CPY and bridging interaction with CPY ***-LandauVerwey-Overbeek theory and attachment efficiency calculation indicated that high energy barriers were responsible for the high mobility of CPY colloids,while the retention of CPY in sands was mainly caused by secondary energy minimum and physically *** findings of this work can help to evaluate the fate of soil passivation remediation products in natural water and soil.

关键词： Chloropyromorphite DLVO theory Stability Saturated porous medium Transport

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The Existence of a Meridional Curve in Closed Incompressible Surfaces in Fully Alternating Link Complements

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Chinese Annals of Mathematics,Series B 2024年第1期45卷 73-80页

作者： wei LIN School of Mathematical Sciences Dalian University of TechnologyDalian 116024LiaoningChina

Menasco showed that a closed incompressible surface in the complement of a non-split prime alternating link in S^(3) contains a circle isotopic in the link complement to a meridian of the *** on this result,he was able to argue the hyperbolicity of non-split prime alternating links in *** et *** that if F■S×I\L is an essential torus,then F contains a circle which is isotopic in S×I\L to a meridian of *** author generalizes his result as follows:Let S be a closed orientable surface,L be a fully alternating link in S×I\If F ■ S×I\L is a closed essential surface,then F contains a circle which is isotopic in S×I\L to a meridian of L.

关键词： Fully alternating Incompressible surfaces Meridionally incompressible

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Zeros of Complete Symmetric Polynomials over Finite Fields

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Journal of Systems Science & Complexity 2024年第4期37卷 1772-1788页

作者： CAO wei School of Mathematics and Statistics Minnan Normal UniversityZhangzhou 363000China

Wan and Zhang(2021) obtained a nontrivial lower bound for the number of zeros of complete symmetric polynomials over finite fields,and proposed a problem whether their bound can be *** this paper,the author improves Wan-Zhang's bound from three *** proposed results are based on the estimates related to the number of certain permutations and the value sets of non-permutation polynomials associated to the complete symmetric *** the author believes that there are still possibilities to improve the bounds and hence Wan-Zhang's bound.

关键词： Complete symmetric polynomial finite field permutation polynomial value set

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