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Optimizing evasive maneuvering of planes using a flight quality driven model

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Science China(Information Sciences) 2024年第3期67卷 197-208页

作者： chang LIU Shaoshan sun Chenggang TAO Yingxin SHOU bin XU School of Automation Northwestern Polytechnical University Chengdu Aircraft Design & Research Institute of AVIC

This paper investigates the optimal evasive maneuver for a plane to avoid an incoming missile. To accurately model the system dynamics while improving computational efficiency, a simplified plane model based on flight quality is established. A missile model with proportional guidance is also *** problem of determining the optimal evasion plane maneuver is formulated. The Gauss pseudospectral method(GPM) is proposed as a solution to find the optimal maneuver. The optimized maneuver is validated by testing it on a high-fidelity 6-degree-of-freedom(6-DOF) model, which demonstrates the effectiveness of the proposed simplified plane model. The Monte Carlo method is employed to evaluate the capability of the plane to evade missiles in various scenarios and elucidate general principles for successful evasion.

关键词： optimal maneuver flying quality evasive strategy pursuit-evasion game air-to-air combat

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Al-doped ZnO/WO_(3) heterostructure films prepared by magnetron sputtering for isopropanol sensors

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Rare Metals 2024年第1期43卷 247-256页

作者： Wei-Xiang Gao Xue-Ting chang Xiao-Jie Zhu Jun-Feng Li Ying-chang Jiang Dong-Sheng Wang Chuan-Xiao Yang Shi-bin sun College of Logistics Engineering Shanghai Maritime UniversityShanghai 201306China College of Ocean Science and Engineering Shanghai Maritime UniversityShanghai 201306China Institute of Logistics Science and Engineering Shanghai Maritime UniversityShanghai 201306China

Metal oxide semiconductors(MOSs) are ideal sensing materials for detecting volatile organic compounds due to their low cost, diversity, high stability, and ease of production. However, it remains a grand challenge to develop the MOSs-based gas sensors for sensing isopropanol with desired performance via a simple, effective,and controllable method. Herein, we reported the preparation of the Al-doped Zn O(AZO)/WO_(3) heterostructure films by directly depositing the AZO coating onto the WO_(3) coating using a strategy of magnetron sputtering. The AZO/WO_(3) heterostructure films were constructed by numbers of irregular nanoparticles that were interconnected with each other. The AZO/WO_(3) heterostructure films-based gas sensors exhibited excellent isopropanolsensing performance with high response, promising selectivity, low detection limit, fast response rate, wide detection range, and ideal reproducibility. The promising isopropanol-sensing performance of the AZO/WO_(3) heterostructure films arises mainly from their high uniformity, unique microstructures with high surface roughness,and the construction of the heterostructure between the AZO and WO_(3) coatings. This work provides a versatile approach to prepare the MOSs-based heterostructure films for assembling the gas sensors.

关键词： Metal oxide semiconductors Gas sensors Aldoped ZnO/WO_(3) Heterostructure films Isopropanol Magnetron sputtering

Skill enhancement learning with knowledge distillation

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Science China(Information Sciences) 2024年第8期67卷 206-220页

作者： Naijun LIU Fuchun sun bin FANG Huaping LIU Department of Computer Science and Technology Tsinghua University

Skill learning through reinforcement learning has significantly progressed in recent years. However, it often struggles to efficiently find optimal or near-optimal policies due to the inherent trial-and-error exploration in reinforcement learning. Although algorithms have been proposed to enhance skill learning efficacy, there is still much room for improvement in terms of skill learning performance and training stability. In this paper, we propose an algorithm called skill enhancement learning with knowledge distillation(SELKD), which integrates multiple actors and multiple critics for skill learning. SELKD employs knowledge distillation to establish a mutual learning mechanism among actors. To mitigate critic overestimation bias,we introduce a novel target value calculation method. We also perform theoretical analysis to ensure the convergence of SELKD. Finally, experiments are conducted on several continuous control tasks, illustrating the effectiveness of the proposed algorithm.

关键词： skill learning enhancement learning reinforcement learning knowledge distillation

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Molecular Chaperone-Dependent Polymer Translocation through Nanopores: The Effects of Chaperone Concentration and Chaperone-Polymer Interaction

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Chinese Journal of Polymer Science 2024年第1期42卷 125-132,I0011页

作者： chang-Sheng Zuo Kang Wang Li-Zhen sun Ting-Ting sun Department of Physics Zhejiang University of Science and TechnologyHangzhou 310023China Department of Applied Physics Zhejiang University of TechnologyHangzhou 310014China

The polymer translocation through a nanopore from a donor space(or named cis side) to a receiver space(trans side) in the chaperone-induced crowded environment has attracted increasing attention in recent years due to its significance in biological systems and technological applications. In this work, we mainly focus on the effects of chaperone concentration and chaperone-polymer interaction on the polymer translocation. By assuming the polymer translocation to be a quasi-equilibrium process, the free energy F of the polymer can be estimated by Rosenbluth-Rosenbluth method and then the translocation time τ can be calculated by Fokker-Plank equation based on the obtained free energy landscape. Our calculation results show that the translocation time can be controlled by independently tuning the chaperone concentration and chaperone-polymer interaction at the cis side or the trans side. There exists a critical chaperone-polymer attraction ε~*=-0.2 at which the volume exclusion and interaction effects of the chaperone can balance each other. Additionally, we also find that at large chaperone-polymer attraction, the translocation time is mainly governed by the diffusion coefficient of the polymer.

关键词： Polymer translocation Rosenbluth-Rosenbluth method Fokker-Plank equation Free energy landscapes

Distinct but correct: generating diversified and entity-revised medical response

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Science China(Information Sciences) 2024年第3期67卷 94-113页

作者： bin LI bin sun Shutao LI Encheng CHEN Hongru LIU Yixuan WENG Yongping BAI Meiling HU College of Electrical and Information Engineering Hunan University School of Mathematics Sun Yat-sen University JD Technology National Laboratory of Pattern Recognition Institute of AutomationChinese Academy of Sciences Xiangya Hospital of Central South University Teaching and Research Section of Clinical Nursing Xiangya Hospital of Central South University

Medical dialogue generation(MDG) is applied for building medical dialogue systems for intelligent consultation. Such systems can communicate with patients in real time, thereby improving the efficiency of clinical diagnosis. However, predicting correct entities and correctly generating distinct responses remain a great challenge. Inspired by actual doctors’ responses to patients, we consider MDG a two-stage task: entity prediction and dialogue generation. For entity prediction, we design an ent-mac post pre-training strategy by leveraging external medical entity knowledge to enhance the pre-trained model. For dialogue generation, we propose an entity-aware fusion MDG method in which predicted entities are integrated into the dialogue generation model through different encoding fusion mechanisms, using information from different sources. Because the diverse beam search algorithm can produce responses with entities that deviate from the predicted entities, an entity-revised diverse beam search is proposed to correct the entities entailed in the generated responses and make the generated responses more distinct. The experimental results on the China Conference on Knowledge Graph and Semantic Computing 2021(A/B tests) and the International Conference on Learning Representations 2021(online test) datasets show that the proposed method outperforms several state-of-the-art methods, which demonstrates its practicability and effectiveness.

关键词： medical entity prediction ent-mac post pre-training strategy entity-aware fusion medical dialogue generation encoding fusion mechanism entity-revised diverse beam search

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Mussel-inspired PTW@PDA composites for developing high-energy gun propellants with reduced erosion and enhanced mechanical strength

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Defence Technology（防务技术） 2024年第2期32卷 675-690页

作者： Xijin Wang Zhitao Liu Pengfei sun Feiyun Chen bin Xu Xin Liao School of Chemistry and Chemical Engineering Nanjing University of Science and TechnologyNanjing 210094JiangsuChina China North Industries Group Corporation Limited Beijing 100045China

The severe erosion and inadequate mechanical strength are prominent challenges for high-energy gun *** address it,novel PTW@PDA composites was prepared by polydopamine(PDA)-modifying onto potassium titanate whisker(PTW,K_(2)Ti_(6)O_(13)),and after was incorporated into gun propellant as erosion-reducing and mechanical-reinforcing *** interfacial characterizations results indicated that as-prepared PTW@PDA composites exhibits an enhanced surface compatible with propellant matrix,thereby facilitating their dispersion into propellants more effectively than raw PTW *** to original propellants,PTW@PDA-modified propellants exhibited significant less erosion,with a Ti-Kbased protective coating being detected on the eroded *** 0.5 wt%and 1.0 wt%addition of PTW@PDA significantly improved impact,compressive and tensile strength of *** the inevitably reduction in relative force,PTW@PDA slightly increase propellant burning rate while exerting little adverse impact on propellant dynamic *** strategy can provide a promising alternative to develop high-energy gun propellant with less erosion and more mechanical strength.

关键词： High energy gun propellant Potassium titanate whiskers Polydopamine modification Erosion inhibitors Mechanical reinforcing fillers

Ligand-controlled electrochemiluminescence generation from CdSe/CdS/ZnS core/shell/shell quantum dots

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Nano Research 2024年第8期17卷 7776-7785页

作者： Hui sun Zhiyuan Cao Haiyan Qin Xiaogang Peng bin Su Key Laboratory of Excited-State Materials of Zhejiang Province Department of ChemistryZhejiang UniversityHangzhou 310058China

The CdSe/CdS/ZnS core/shell/shell quantum dots(QDs)with strong exciton confinement have manifested themselves as competitive light-emitting materials in electrochemiluminescence(ECL).However,cathodic ECL generation by these QDs requires the injection of electron and hole from solid electrode and electrogenerated radicals(for example SO_(4)•^(−)),which is inevitably influenced by not only the inorganic structure of QDs but also the organic ligands on the *** this work we aimed at studying the impact of surface organic ligands on ECL performance of CdSe/CdS/ZnS *** changing the surface ligand from oleate to acetate,we phenomenologically observed the positive shift of ECL onset potential by ca.200 mV and the increase of ECL intensity by~100 times,suggesting that a short ligand is more favorable for ECL *** further comprehend the ligand effect,we measured the charge injection kinetics using potential-modulated,time-resolved photoluminescence,and thinlayer spectroelectrochemistry *** electron and hole injection into QDs were found to be accelerated by 2–20 times if shortening the ligand from oleate to acetate,confirming the significant impact of surface ligands on ECL performance of *** study is expected to provide guidance on how to design surface functionalized QDs for specific applications such as ECL immunodiagnosis,photocatalysis,and photovoltaics.

关键词： electrochemiluminescence quantum dots spectroelectrochemistry surface ligands charge injection charge transfer

Exact Box-Constrained Economic Operating Region for Power Grids Considering Renewable Energy Sources

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Journal of Modern Power Systems and Clean Energy 2024年第2期12卷 514-523页

作者： Huating Xu bin Feng Chutong Wang Chuangxin Guo Jian Qiu Mingyang sun College of Electrical Engineering Zhejiang UniversityHangzhou 310027China Department of Control Science and Engineering Zhejiang UniversityHangzhou 310027China

The growing integration of renewable energy sources manifests as an effective strategy for reducing carbon emissions. This paper strives to efficiently approximate the set of optimal scheduling plans(OSPs) to enhance the performance of the steady-state adaptive cruise method(SACM) of power grid, improving the ability of dealing with operational uncertainties. Initially, we provide a mathematical definition of the exact boxconstrained economic operating region(EBC-EOR) for the power grid and its dispatchable components. Following this, we introduce an EBC-EOR formulation algorithm and the corresponding bi-level optimization models designed to explore the economic operating boundaries. In addition, we propose an enhanced big-M method to expedite the computation of the EBCEOR. Finally, the effectiveness of the EBC-EOR formulation, its economic attributes, correlation with the scheduling plan underpinned by model predictive control, and the significant improvement in computational efficiency(over twelvefold) are verified through case studies conducted on two test systems..

关键词： Exact box-constrained economic operating region(EBC-EOR) big-M method intelligent scheduling steady-state adaptive cruise uncertainty renewable energy source

Special Unipotent Representations of Simple Linear Lie Groups of Type A

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Acta Mathematica Sinica,English Series 2024年第3期40卷 707-716页

作者： Dan BARBASCH Jia Jun MA bin Yong sun Chen Bo ZHU Department of Mathematics Cornell UniversityIthacaNY 14853USA School of Mathematical Sciences Xiamen UniversityXiamen 361005P.R.China Department of Mathematics Xiamen University Malaysia CampusSepangSelangor Darul Ehsan43900Malaysia Institute for Advanced Study in Mathematics&New Cornerstone Science Laboratory Zhejiang UniversityHangzhou 310058P.R.China Department of Mathematics National University of Singapore10 Lower Kent Ridge RoadSingapore 119076

Let G be a special linear group over the real,the complex or the quaternion,or a special unitary *** this note,we determine all special unipotent representations of G in the sense of Arthur and Barbasch-Vogan,and show... 详细信息

关键词： Special unipotent representations unitary representations coherent continuation Weyl group representations