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Upconverting and downshifting circularly polarized luminescence in a superstructural helix

Science China Chemistry 2024年第8期67卷 2571-2577页

作者： Honghan Ji bin wu Enquan Tian Chao Ren Xue Jin Liangliang Zhu Pengfei duan CAS Key Laboratory of Nanosystem and Hierarchical Fabrication National Center for Nanoscience and Technology(NCNST)Beijing 100190China State Key Laboratory of Molecular Engineering of Polymers Department of Macromolecular ScienceFudan UniversityShanghai 200438China University of Chinese Academy of Sciences Beijing 101408China

The modulation of circularly polarized luminescence(CPL) has become an increasingly prominent area of research. In this study,we propose a unique “one-excitation-to-three-emissions” CPL system through the co-assembly of an upconversion system,incorporating one sensitizer(Pt(II) mesotetraphenyl tetrabenzoporphyrine, Pt TPBP) and two annihilators(R/S-DPA and R/SBDP) within liquid crystals. The chiral nature of the annihilators induces a transformation of the nematic liquid crystal into chiral nematic liquid crystals(N*LC), establishing an excellent chiral matrix. Upon the incorporation of the sensitizer Pt TPBP and subsequent excitation at 635 nm, the system demonstrates two independent triplet–triplet annihilation photon upconversion(TTA-UC) with the emission in blue and yellow, aided by thermally activated triplet–triplet energy transfer(TTET). This is accompanied by the simultaneous generation of upconverting circularly polarized luminescence(UC-CPL) and downshifting near-infrared circularly polarized luminescence(DS-CPL) originating from the residual luminescence of Pt TPBP. Remarkably,fine-tuning the ratio between the two annihilators allows the TTA-UC system to exhibit multicolor CPL emission with an amplified luminescence dissymmetry factor(glum, reaching up to 0.6). Our study unveils a previously unreported “one-excitation-to-three-emissions” system and provides a versatile strategy for modulating CPL emissions, surpassing conventional methodologies.

关键词： circularly polarized luminescence triplet–triplet annihilation upconversion near-infrared emission chiral nematic liquid crystal luminescence dissymmetry factor

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Drogue detection for autonomous aerial refueling via hybrid pigeon-inspired optimized color opponent and saliency aggregation

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Chinese Journal of Aeronautics 2024年第5期37卷 27-38页

作者： Tongyan wu Haibin duan Yanming FAN State Key Laboratory of Virtual Reality Technology and Systems School of Automation Science and Electrical EngineeringBeihang UniversityBeijing 100083China Virtual Reality Fundamental Research Laboratory Department of Mathematics and TheoriesPeng Cheng LaboratoryShenzhen 518000China AVIC Shenyang Aircraft Design and Research Institute Shenyang 110035China

Drogue detection is one of the challenging tasks in autonomous aerial refueling due to the requirement for accuracy and *** detection based on image intrinsic cues can achieve fast detection,but with poor *** studies reveal that optimization-based methods provide accurate and quick solutions for saliency *** paper presents a hybrid pigeon-inspired optimization method,the optimized color opponent,that aims to adjust the weight of color opponent channels to detect the drogue *** can optimize the weights in the selected aerial refueling scene offline,and the results are applied for drogue detection in the scene.A novel algorithm aggregated by the optimized color opponent and robust background detection is presented to provide better precision and *** results on benchmark datasets and aerial refueling images show that the proposed method successfully extracts the saliency region or drogue and exhibits superior performance against the other saliency detection methods with intrinsic *** algorithm designed in this paper is competent for the drogue detection task of autonomous aerial refueling.

关键词： Autonomous aerial refueling Drones Hybrid pigeon-inspired optimization Color opponent Saliency detection Saliency aggregation

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Exclusive Hypothesis Testing for Cox's Proportional Hazards Model

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Journal of Systems Science & Complexity 2024年第5期37卷 2157-2172页

作者： wu Qiang TONG Xingwei duan Xiaogang School of Statistics Beijing Normal UniversityBeijing 100875China

Exclusive hypothesis testing is a new and special class of hypothesis *** kind of testing can be applied in survival analysis to understand the association between genomics information and clinical information about the survival ***,it is well known that Cox's proportional hazards model is the most commonly used model for regression analysis of failure *** this paper,the authors consider doing the exclusive hypothesis testing for Cox's proportional hazards model with right-censored *** authors propose the comprehensive test statistics to make decision,and show that the corresponding decision rule can control the asymptotic TypeⅠerrors and have good powers in *** numerical studies indicate that the proposed approach works well for practical situations and it is applied to a set of real data arising from Rotterdam Breast Cancer Data study that motivated this study.

关键词： Comprehensive test statistics Cox’s proportional hazards model exclusive hypothesis testing right-censored data Type I error

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Prescribed-time leader-following consensus of linear multi-agent systems by bounded linear time-varying protocols

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Science China(Information Sciences) 2024年第1期67卷 140-153页

作者： Kai ZHANG bin ZHOU Xuefei YANG Guangren duan Center for Control Theory and Guidance Technology Harbin Institute of Technology

This paper considers the prescribed-time leader-following consensus problem of input-constrained linear multi-agent systems under generally directed communication topology in two cases:the Laplacian matrix related to the entire communication topology between agents is either known or *** particular,the consensus problem for the former case is solved by a novel bounded linear time-varying(LTV) protocol,where the feedback gain is formulated by the parametric Lyapunov equation and the knowledge of the Laplacian ***,by utilizing a distributed observer,a fully bounded LTV protocol is proposed for the latter *** should be noted that,compared with the existing results,the system under consideration is more general,the designed protocols are linear,and the consensus problem is accomplished even in a fully distributed ***,the effectiveness of the proposed approach is verified by a numerical example.

关键词： leader-following consensus time-vary feedback prescribed-time control fully distributed consensus

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Efficient continuous synthesis of 2-hydroxycarbazole and 4-hydroxycarbazole in a millimeter scale photoreactor

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Chinese Chemical Letters 2024年第4期35卷 399-403页

作者： Zhixiang Li Zhirong Yang Chang Yao bin wu Gang Qian Xuezhi duan Xinggui Zhou Jing Zhang State Key Laboratory of Chemical Engineering East China University of Science and TechnologyShanghai 200237China School of Chemical Engineering Zhengzhou UniversityZhengzhou 450001China

2-Hydroxycarbazole and 4-hydroxycarbazole are important chemicals with extensive applications in optoelectronic materials and pharmaceutical *** of the art yield of 2-hydroxycarbazole is~30%and the reaction time is typically in hours or ***,we developed a green route for the continuous and high-throughput synthesis of 2-hydroxycarbazole and 4-hydroxycarbazole via photochemical intramolecular cyclization of 3–hydroxy-2–chloro-diphenylamine using a self-designed millimeter scale photoreactor,which was designed based on sizing-up and numbering-up strategies for a decent liquid holdup(6.8 m L)and fabricated via femtosecond laser engraving *** photochemical synthesis was carried out continuously under the illumination of 365 nm UV-LED with dimethyl sulfoxide as solvent and potassium t-butoxide as *** was found that under optimized conditions a 2-hydroxycarbazole yield of 31.6%and a 4-hydroxycarbazole yield of 11.1%were obtained with a residence time of 1 *** to semibatch operations,the reaction time was shortened by 1–2 orders of *** a result,a throughput of 11.3 g/day 2-hydroxycarbazole and 4.0 g/day 4-hydroxycarbazole can be achieved from the *** was proposed that the short reaction time and high product yield are resulted from higher photon transfer rates and more uniform photon distribution provided by the millimeter scale photoreactor,which enhances the reaction rates and mitigates overreaction.

关键词： Millimeter scale reactor 2-Hydroxycarbazole Photochemistry UV-LED Process intensification

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On the two-layer high-level Green-Naghdi model in a general form

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Journal of Hydrodynamics 2024年第1期36卷 78-86页

作者： bin-bin Zhao Tian-yu Zhang Zhan Wang Wen-yang duan Alexander Chesnokov Natalia Shmakova College of Shipbuilding Engineering Harbin Engineering UniversityHarbin150001China Qingdao Innovation and Development Center of Harbin Engineering University Qingdao266000China Lavrentyev Institute of Hydrodynamics NovosibirskRussia

The traditional high-level Green-Naghdi(HLGN)model,which uses the polynomial as the shape function to approximate the variation of the horizontal-and vertical-velocity components along the vertical direction for each-fluid layer,can accurately describe the large-amplitude internal waves in a two-layer system for the shallow configuration(h_(2)/λ■1,h_(1)/λ■1).However,for the cases of the deep configuration(h_(2)/λ■1,h_(1)/λ=O(1)),higher-order polynomial is needed to approximate the variation of the velocity components along the vertical direction for the lower-fluid ***,however,introduces additional unknowns,leading to a significant increase in computational *** paper,for the first time,derives a general form of the HLGN model for a two-layer fluid system,where the general form of the shape function is used during the *** obtaining the general form of the two-layer HLGN equations,corresponding solutions can be obtained by determining the reasonable shape ***-amplitude internal solitary waves in a deep configuration are studied by use of two different HLGN *** of the two HLGN models shows that the polynomial as the shape function for the upper-fluid layer and the production of exponential and polynomial as the shape function for the lower-fluid layer is a good *** comparing with Euler’s solutions and the laboratory measurements,the accuracy of the two-layer HLGN model is verified.

关键词： High-level Green-Naghdi(HLGN)model general form internal waves deep configuration

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Prescribed time control based on the periodic delayed sliding mode surface without singularities

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Science China(Information Sciences) 2024年第7期67卷 256-270页

作者： bin ZHOU Yi DING Kang-Kang ZHANG Guang-Ren duan Center for Control Theory and Guidance Technology Harbin Institute of Technology

In this paper, nonsingular prescribed-time control is studied based on periodic delayed sliding mode surfaces. Different from the existing sliding mode control, where either singularity problems may appear or the convergence time depends on the initial state, the proposed sliding mode control approaches can achieve prescribed-time convergence without singularity. The proposed nonsingular sliding mode control approaches can be applied to both second-order and high-order nonlinear systems with prescribed-time convergence. As applications of the proposed sliding mode control approaches, the control of hypersonic vehicle systems is revisited. Numerical simulations on the nonlinear model of the hypersonic vehicle system show the effectiveness of the proposed methods.

关键词： prescribed-time control smooth periodic delayed feedback sliding mode control high-order nonlinear systems hypersonic vehicle systems

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DLP:towards active defense against backdoor attacks with decoupled learning process

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Cybersecurity 2024年第1期7卷 122-134页

作者： Zonghao Ying bin wu State Key Laboratory of Information Security Institute of Information EngineeringChinese Academy of SciencesBeijingChina School of Cyber Security University of Chinese Academy of SciencesBeijingChina

Deep learning models are well known to be susceptible to backdoor attack,where the attacker only needs to provide a tampered dataset on which the triggers are *** trained on the dataset will passively implant the backdoor,and triggers on the input can mislead the models during *** study shows that the model shows different learning behaviors in clean and poisoned subsets during *** on this observation,we propose a general training pipeline to defend against backdoor attacks *** models can be trained from the unreli-able dataset by decoupling the learning process into three stages,i.e.,supervised learning,active unlearning,and active semi-supervised *** effectiveness of our approach has been shown in numerous experiments across various backdoor attacks and datasets.

关键词： Deep learning Backdoor attack Active defense

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An improved bound on accelerated light dark matter

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Science China(Physics,Mechanics & Astronomy) 2024年第2期67卷 105-118页

作者： Liangliang Su Lei wu bin Zhu Department of Physics and Institute of Theoretical Physics Nanjing Normal UniversityNanjing 210023China School of Physics Yantai UniversityYantai 264005China

Light(sub-GeV)dark matter has gained increasing interest in terms of direct *** dark matter is a promising candidate that can generate detectable nuclear recoil energy within the sub-GeV *** of the large kinetic energy,its interactions with the nucleus are predominantly governed by inelastic scattering,including quasi-elastic and deep inelastic *** this work,we calculated the inelastic effects in dark matter-Earth scattering mediated by a vector *** analysis revealed that the impact of inelastic scattering relies on the mediator mass and the kinetic energy spectrum of dark *** results exhibited considerable disparity:the upper bounds of the exclusion limit for the spin-independent cross-section between accelerated dark matter and nuclei via a heavy mediator differ by several tens of times when inelastic scattering is considered.

关键词： accelerated dark matter inelastic scattering direct detection experiment

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Topology design and graph embedding for decentralized federated learning

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Intelligent and Converged Networks 2024年第2期5卷 100-115页

作者： Yubin duan Xiuqi Li Jie wu Department of Computer and Information Sciences Temple UniversityPhiladelphiaPA 19122USA

Federated learning has been widely employed in many applications to protect the data privacy of participating *** the dataset is decentralized among training devices in federated learning,the model parameters are usually stored in a centralized *** federated learning is easy to implement;however,a centralized scheme causes a communication bottleneck at the central server,which may significantly slow down the training *** improve training efficiency,we investigate the decentralized federated learning *** decentralized scheme has become feasible with the rapid development of device-to-device communication techniques under ***,the convergence rate of learning models in the decentralized scheme depends on the network topology *** propose optimizing the topology design to improve training efficiency for decentralized federated learning,which is a non-trivial problem,especially when considering data *** this paper,we first demonstrate the advantage of hypercube topology and present a hypercube graph construction method to reduce data heterogeneity by carefully selecting neighbors of each training device—a process that resembles classic graph *** addition,we propose a heuristic method for generating torus ***,we have explored the communication patterns in hypercube topology and propose a sequential synchronization scheme to reduce communication cost during training.A batch synchronization scheme is presented to fine-tune the communication pattern for hypercube *** on real-world datasets show that our proposed graph construction methods can accelerate the training process,and our sequential synchronization scheme can significantly reduce the overall communication traffic during training.

关键词： data heterogeneity decentralized federated learning graph embedding network topology

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