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Density-based ship detection in SAR images:Extension to a self-similarity perspective

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Chinese Journal of Aeronautics 2024年第3期37卷 168-180页

作者： Xueqian WANG Gang LI Zhizhuo JIANG Yu LIU You HE department of Electronic Engineering Tsinghua UniversityBeijing 100084China shenzhen international Graduate school Tsinghua UniversityShenzhen 518055China

Nonlocal self-similarity is an important property of Synthetic Aperture Radar(SAR)images to characterize the repetitiveness of features embodied by SAR images within nonlocal areas and has been used for enhancement of SAR images.Existing SAR ship detectors often independently handle small sub-images cropped from a large marine SAR image and do not exploit the nonlocal self-similarity therein.In this paper,we propose a new ship detector from the perspective of nonlocal self-similarity in SAR images to improve the ship detection performance,basically including three stages:prescreening,intra-cue calculation,and inter-cue calculation.In the prescreening stage,we design a new Histogram-based Density(HD)feature to rapidly select candidate sub-images potentially containing ship targets from a large SAR image.In the intra-cue calculation stage,target cues within a single candidate sub-image are extracted.In the inter-cue calculation stage,thanks to the nonlocal self-similarity among different candidate sub-images in terms of density features,we innovatively extract a weighted superpixel-HD map to obtain accumulated intracues across all the candidate sub-images.Finally,for each candidate sub-image,we fuse its inter-cue and intra-cue to obtain final detection results.Experimental results based on real SAR images show that our newly proposed method provides a better target-to-clutter contrast and ship detection performance than those of other state-of-the-art detection approaches.

关键词： Ship detection Synthetic aperture radar(SAR) Density Self-similarity Histogram

A large-scale cold plasma jet: generation mechanism and application effect

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Plasma Science and Technology 2024年第4期26卷 1-8页

作者：崔伟胜张若兵 shenzhen international Graduate school Tsinghua UniversityShenzhen 518055People’s Republic of China

Atmospheric pressure cold plasma jets(APCPJs) typically exhibit a slender, conical structure,which imposes limitations on their application for surface modification due to the restricted treatment area. In this paper, we introduce a novel plasma jet morphology known as the large-scale cold plasma jet(LSCPJ), characterized by the presence of both a central conical plasma jet and a peripheral trumpet-like diffuse plasma jet. The experimental investigations have identified the factors influencing the conical and the trumpet-like diffuse plasma jet, and theoretical simulations have shed light on the role of the flow field and the electric field in shaping the formation of the LSCPJ. It is proved that, under conditions of elevated helium concentration, the distributions of impurity gas particles and the electric field jointly determine the plasma jet’s morphology. High-speed ICCD camera images confirm the dynamic behavior of plasma bullets in LSCPJ, which is consistent with the theoretical analysis. Finally, it is demonstrated that when applied to the surface treatment of silicone rubber, LSCPJ can achieve a treatment area over 28 times larger than that of APCPJ under equivalent conditions. This paper uncovers the crucial role of impurity gases and electric fields in shaping plasma jet morphology and opens up the possibility of efficiently diversifying plasma jet generation effects through external electromagnetic fields. These insights hold the promise of reducing the generation cost of plasma jets and expanding their applications across various industrial sectors.

关键词： diffuse plasma jet flow field electric field surface treatment

Recent progress about transmission electron microscopy characterizations on lithium-ion batteries

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Journal of Energy Chemistry 2024年第8期95卷 39-56页

作者： Yihang Liu Qiuyun Li Ziqiang Wang Institute of Materials Research Shenzhen International Graduate School Tsinghua University

With the rapid development of portable electronics, new energy vehicles, and smart grids, ion batteries are becoming one of the most widely used energy storage devices, while the safety concern of ion batteries has always been an urgent problem to be solved. To develop a safety-guaranteed battery, the characterization of the internal structure is indispensable, where electron microscopy plays a crucial role. Based on this, this paper summarizes the application of transmission electron microscopy(TEM) in battery safety, further concludes and analyzes the aspects of dendrite growth and solid electrolyte interface(SEI) formation that affect the safety of ion batteries, and emphasizes the importance of electron microscopy in battery safety research and the potential of these techniques to promote the future development of this field. These advanced electron microscopy techniques and their prospects are also discussed.

关键词： Dendrites Electron microscopy characterizations Lithium-ion batteries SEI

Optimal Time-of-use Pricing for Renewable Energy-powered Microgrids: A Multi-agent Evolutionary Game Theory-based Approach

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CSEE Journal of Power and Energy Systems 2024年第1期10卷 162-174页

作者： Yu Zeng Yinliang Xu Xinwei Shen Hongbin Sun Tsinghua-Berkeley shenzhen Institute.Tsinghua shenzhen international Graduate school Tsinghua UniversityShenzhen 518055China department of Electrical Engineering Tsinghua UniversityBeijing 100084China

While price schedules can help improve the economic efficiency of renewable energy-powered microgrids,timeof-use(TOU)pricing has been identified as an effective way for microgrid development,which is presently limited by its high costs.In this study,we propose an evolutionary game theoretic model to explore optimal TOU pricing for development of renewable energy-powered microgrids by applying a multi-agent system,that comprises a government agent,local utility company agent,and different types of consumer agents.In the proposed model,we design objective functions for the company and the consumers and obtain a Nash equilibrium using backward induction.Two pricing strategies,namely,the TOU seasonal pricing and TOU monthly pricing,are evaluated and compared with traditional fixed pricing.The numerical results demonstrate that TOU schedules have significant potential for development of renewable energy-powered microgrids and are recommended for an electric company to replace traditional fixed pricing.Additionally,TOU monthly pricing is more suitable than TOU seasonal pricing for microgrid development.

关键词： Game theory microgrid multi-agent system renewable energy time-of-use pricing

Design and application of copper/lithium composite anodes for advanced lithium metal batteries

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Rare Metals 2024年第3期43卷 942-970页

作者： Bin Zhang Ji-Ping Ma Yang Zhao Tong Li Jin-Lin Yang Zhan-Ling Zhang Shi-Zhong Wei Guang-Min Zhou school of Materials Science and Engineering Henan University of Science and TechnologyLuoyang 471003China shenzhen Geim Graphene Center Tsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhen 518055China school of Physical and Mathematical Sciences Nanyang Technological UniversitySingapore 637371Singapore shenzhen Geim Graphene Center Tsinghua-Berkeley Shenzhen InstituteTsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhen 518055China

Lithium(Li)is a promising candidate for nextgeneration battery anode due to its high theoretical specific capacity and low reduction potential.However,safety issues derived from the uncontrolled growth of Li dendrite and huge volume change of Li hinder its practical application.C onstructing dendrite-free composite Li anodes can significantly alleviate the above problems.Copper(Cu)-based materials have bee n widely used as substrates of the composite electrodes due to their chemical stability,excellent conductivity,and good mechanical strength.Copper/lithium(Cu/Li)composite anodes significantly regulate the local current density and decrease Li nucleation overp otential,realizing the uniform and dendrite-free Li deposition.In this review,Cu/Li composite methods including electrodeposition,melting infusion,and mechanical rolling are systematically summarized and discussed.Additionally,design strategies of Cu-based current collectors for high performance Cu/Li composite anodes are illustrated.General challenges and future development for Cu/Li composite anodes are presented and postulated.We hope that this review can provide a comprehensive understanding of Cu/Li composite methods of the latest development of Li metal anode and stimulate more research in the future.

关键词： Lithium metal batteries Cu/Li composite anode Electrodeposition Thermal melting infusion Mechanical rolling

BET inhibitors enhance the anti-cancer effect of etoposide by suppressing the MRN-ATM axis in the DNA damage response

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Genes & Diseases 2024年第1期11卷 19-22页

作者： Zhenhai Li Wenchao Xu Feng Chen Jun Zhang Wei-Guo Zhu Guangdong Key Laboratory of Genome Instability and Human Disease Prevention Department of Biochemistry and Molecular BiologyShenzhen University School of MedicineShenzhenGuangdong 518055China school of Pharmaceutical Sciences Shenzhen University Health Science CenterShenzhenGuangdong 518055China Base for international Science and Technology Cooperation:Carson Cancer Stem Cell Vaccines R&D Center International Cancer CenterShenzhen University Health Science CenterShenzhenGuangdong 518055China shenzhen Bay Laboratory Shenzhen University School of MedicineShenzhenGuangdong 518055China Marshall Laboratory of Biomedical Engineering Shenzhen University School of MedicineShenzhenGuangdong 518055China

Etoposide is widely used for cancer chemotherapy in the clinic.However,long-term etoposide treatment can lead to adverse effects or drug resistance.To improve the situation,we evaluated the therapeutic efficiency of etoposide combined with inhibitors of bromodomain and extraterminal(BET)family proteins,which have recently emerged as novel anti-cancer targets due to their critical roles in cancer development.Firstly,we showed BRD4,one of the main targets of BET inhibitors,was involved in DNA damage response(DDR)via the homologous recombination(HR)repair pathway.

关键词： etoposide damage cancer

An in-situ polymerized interphase engineering for high-voltage allsolid- state lithium-metal batteries

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Nano Research 2024年第4期17卷 2687-2692页

作者： Lu Nie Shaojie Chen Mengtian Zhang Tianyi Gao Yuyao Zhang Ran Wei Yining Zhang Wei Liu school of Physical Science and Technology ShanghaiTech UniversityShanghai 201210China Tsinghua-Berkeley shenzhen Institute&Tsinghua shenzhen international Graduate school Tsinghua UniversityShenzhen 518055China

All-solid-state lithium batteries(ASSLBs)have attracted great interest due to their promising energy density and strong safety.However,the interface issues,including large interfacial resistance between electrode and electrolyte and low electrochemical stability of solid-state electrolytes against high-voltage cathodes,have restricted the development of high-voltage ASSLBs.Herein,we report an ASSLB with stable cycling by adopting a conformal polymer interlayer in-situ formed at the Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)(LLZTO)–cathode interfaces.The polymer can perfectlyﬁll the voids and create a stable interface contact between LLZTO and cathodes.In addition,the electric field across the polymer interlayer is reduced compared with pure solid polymer electrolyte(SPE),which facilitates the electrochemical stability with high-voltage cathode.The all-solid-state Li|LLZTO-SPE|LiFe_(0.4)Mn_(0.6)PO_(4)(LMFP)cells achieve a low interface impedance,high specific capacity,and excellent cycling performance.This work presents an effective and practical strategy to rationally design the electrode–electrolyte interface for the application of high-voltage ASSLBs.

关键词： all-solid-state lithium batteries interface contact electric field electrochemical stability

Considerations of advanced aqueous batteries recycling:A perspective

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Journal of Energy Chemistry 2024年第6期93卷 46-54,I0002页

作者： Yun Zhao Yuqiong Kang Hao Du Feiyu Kang Baohua Li Institute of Materials Research Tsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhen 518055GuangdongChina

1.Introduction Battery technology,serving as a basis for a rechargeable society,has developed rapidly over a century[1].The progress can be roughly divided into three stages,with the initial two mainly focusing on aqueous battery systems.Prior to 1859,research primarily focused on the conceptualization of batteries and the development of primary(non-rechargeable)cells[2].In the subsequent150 years,rechargeable battery technology emerged。

关键词： battery Battery primarily

High-resolution portable lens-free on-chip microscopy with RGB LED via pinhole array

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Chinese Optics Letters 2024年第2期22卷 96-100页

作者：王钦骅马建设曹良才苏萍 Tsinghua shenzhen international Graduate school Tsinghua UniversityShenzhen 518055China department of Precision Instrument Tsinghua UniversityBeijing 100084China

Lens-free on-chip microscopy with RGB LEDs(LFOCM-RGB)provides a portable,cost-effective,and high-throughput imaging tool for resource-limited environments.However,the weak coherence of LEDs limits the high-resolution imaging,and the luminous surfaces of the LED chips on the RGB LED do not overlap,making the coherence-enhanced executions tend to undermine the portable and cost-effective implementation.Here,we propose a specially designed pinhole array to enhance coherence in a portable and cost-effective implementation.It modulates the three-color beams from the RGB LED separately so that the three-color beams effectively overlap on the sample plane while reducing the effective light-emitting area for better spatial coherence.The separate modulation of the spatial coherence allows the temporal coherence to be modulated separately by single spectral filters rather than by expensive triple spectral filters.Based on the pinhole array,the LFOCM-RGB simply and effectively realizes the high-resolution imaging in a portable and cost-effective implementation,offering much flexibility for various applications in resource-limited environments.

关键词： lens-free on-chip microscopy LED phase retrieval pinhole array