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Meta label associated loss for fine-grained visual recognition

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Science China(Information Sciences) 2024年第6期67卷 230-247页

作者： Yanchao li Fu XIAO Hao li Qun li Shui YU School of Computer Science Nanjing University of Posts and Telecommunications School of Network Engineering Zhoukou Normal University School of Computer Science University of Technology Sydney

Recently, intensive attempts have been made to design robust models for fine-grained visual recognition, most notably are the impressive gains for training with noisy labels by incorporating a reweighting strategy into a meta-learning framework. However, it is limited to up or downweighting the contribution of an instance for label reweighting approaches in the learning process. To solve this issue, a novel noise-tolerant method with auxiliary web data is proposed. Specifically, first, the associations made from embeddings of well-labeled data with those of web data and back at the same class are measured. Next, its association probability is employed as a weighting fusion strategy into angular margin-based loss, which makes the trained model robust to noisy datasets. To reduce the influence of the gap between the well-labeled and noisy web data, a bridge schema is proposed via the corresponding loss that encourages the learned embeddings to be coherent. Lastly, the formulation is encapsulated into the meta-learning framework, which can reduce the overfitting of models and learn the network parameters to be noise-tolerant. Extensive experiments are performed on benchmark datasets, and the results clearly show the superiority of the proposed method over existing state-of-the-art approaches.

关键词： label associated loss weighting noisy samples fine-grained visual recognition noise-tolerant learning meta-learning

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Enrichment of Chemical Element ^(7)li in the Rotating Red Clump Star

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Chinese Physics Letters 2024年第8期41卷 121-125页

作者： Fang-Wen Wu Han-Feng Song Qing-li li Yun He Xin-Yue Qu Zhuo Han College of Physics Guizhou UniversityGuiyang 550025China Geneva Observatory University of GenevaCH-1290 SauvernySwitzerland

About 2 percent of red clump stars are found to be the lithium-rich and thus the surface lithium increases obviously in some red clump *** physical mechanism of the lithium enrichment in these stars has not yet been explained satisfactorily by the evolutionary models of single *** flash induced internal gravity wave mixing(i.e.,IGW)could play a primary role in explaining the red clump star with lithium enrichment and it has a very significant impact on the internal structure and surface compositions of a *** can significantly increase the mixing efficiency of the internal gravity wave because the timescale for the enrichment event has been *** mixing can explain the observed behavior of lithium on red giant stars that are more luminosity than the RGB ***,it has a very small effect on the diffusion of elements because its diffusion coefficient is much smaller than the one of IGW induced mixing after the core helium flash.

关键词： flash stars lithium

li_(2)ZnTi_(3)O_(8)as the host–separator modifier with efficient polysulfides trapping and fast li^(+)diffusion for lithium-sulfur batteries

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Nano Research 2024年第7期17卷 6087-6094页

作者： Mao Qian Yakun Tang Lang liu Yue Zhang Xiaohui li JiaJia Chen State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources Xinjiang UniversityUrumqi 830017China State Key Laboratory of Physical Chemistry of Solid Surfaces Xiamen UniversityXiamen 361005China

The diffusion and loss of lithium polysulfides(liPSs)in lithium-sulfur batteries(LSBs)reduce the sulfur utilization rate and the catalytic conversion efficiency of sulfur species,resulting in early battery ***_(2)ZnTi_(3)O_(8)(LZTO),characterized by its stable spinel structure,exhibits high li+conductivity and holds great potential as an effective adsorbent for *** study proposes a collaborative design concept of LZTO host–separator modifier,which offers a complementary and matching approach in the cathode side,effectively addressing the challenges associated with dissolution and inadequate conversion of *** functional theory(DFT)calculation substantiates the pronounced chemical affinity of LZTO towards *** importantly,the high efficiency ion transport channels are achieved in separator coating due to the presence of the LZTO ***,the catalytic efficacy of LZTO is validated through meticulous analysis of symmetric batteries and Tafel ***,the LZTO host–separator modifier-based cell displays satisfactory rate capability(1449 and 1166 mAh·g^(−1)at 0.1 and 0.5 C)and an impressively capacity(606 mAh·g^(−1)after 500 cycles at 1 C).The coordinated strategy of host–separator modifier is supposed to have wide applications in LSBs.

关键词： li_(2)ZnTi_(3)O_(8) lithium-sulfur batteries host-separator modifier catalytic conversion diffusion and loss of liPSs

Challenges in li-ion battery high-voltage technology and recent advances in high-voltage electrolytes

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Journal of Energy Chemistry 2024年第4期91卷 73-98页

作者： Jianguo liu Baohui li Jinghang Cao Xiao Xing Gan Cui Shandong Key Laboratory of Oil&Gas Storage and Transportation Safety College of Pipeline and Civil EngineeringChina University of Petroleum(East China)Qingdao 266580ShandongChina

The electrolyte directly contacts the essential parts of a lithium-ion battery,and as a result,the electrochemical properties of the electrolyte have a significant impact on the voltage platform,charge discharge capacity,energy density,service life,and rate discharge *** raising the voltage at the charge/discharge plateau,the energy density of the battery is ***,this causes transition metal dissolution,irreversible phase changes of the cathode active material,and parasitic electrolyte oxidation *** article presents an overview of these concerns to provide a clear explanation of the issues involved in the development of electrolytes for high-voltage lithium-ion ***,solidstate electrolytes enable various applications and will likely have an impact on the development of batteries with high energy *** is necessary to improve the high-voltage performance of electrolytes by creating solvents with high thermal stabilities and high voltage resistance and additives with superior film forming performance,multifunctional capabilities,and stable lithium *** offer suggestions for the future development of high-energy lithium-ion batteries,we conclude by offering our own opinions and insights on the current development of lithium-ion batteries.

关键词： lithium-ion battery High voltage Electrolyte additive Solid electrolyte

维普期刊数据库

A li_(3)P nanoparticle dispersion strengthened ultrathin li metal electrode for high energy density rechargeable batteries

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Nano Research 2024年第5期17卷 4031-4038页

作者： lin Fu Xiancheng Wang Bao Zhang Zihe Chen Yuanjian li Yongming Sun Provincial Guizhou Key Laboratory of Green Chemical and Clean Energy Technology School of Chemistry and Chemical EngineeringGuizhou UniversityGuiyang 550025China Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan 430074China School of Physical and Mathematical Sciences Nanyang Technological UniversitySingapore 637371Singapore Institute of Materials Research and Engineering Agency for Science Technology and Research(A*STAR)Singapore 138634Singapore

Achievement of lithium(li)metal anode with thin thickness(e.g.,≤30µm)is highly desirable for rechargeable high energy density ***,the fabrication and application of such thin li metal foil electrode remain challenging due to the poor mechanical processibility and inferior electrochemical performance of metallic ***,mechanico-chemical synthesis of robust ultrathin li/li_(3)P(LLP)composite foils(~15µm)is demonstrated by employing repeated mechanical rolling/stacking operations using red P and metallic li as raw *** in-situ formed li+-conductive li_(3)P nanoparticles in metallic li matrix and their tight bonding strengthen the mechanical durability and enable the successful fabrication of free-standing ultrathin li metal composite ***,it also reduces the electrochemical li nucleation barrier and homogenizes li plating/stripping *** matching to high-voltage liCoO_(2),the full cell with a low negative/positive(N/P)capacity ratio of~1.5 offers a high energy density of~522 W·h·kg^(-1) at 0.5 C based on the mass of cathode and *** into account its facile manufacturing,potentially low cost,and good electrochemical performance,we believe that such an ultrathin composite li metal foil design with nanoparticle-dispersion-strengthened mechanism may boost the development of high energy density li metal batteries.

关键词： lithium metal anode high energy density battery mechanico-chemical synthesis ultrathin li/li_(3)P composite foil low negative/positive capacity ratio

Nonreciprocal generation of Schrodinger cat state induced by topology

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Science China(Physics,Mechanics & Astronomy) 2024年第4期67卷 23-30页

作者： Zi-Hao li li-li Zheng Ying Wu Xin-You Lü School of Physics and Institute for Quantum Science and Engineering Huazhong University of Science and Technologyand Wuhan Institute of Quantum TechnologyWuhan 430074China Key Laboratory of Optoelectronic Chemical Materials and Devices of Ministry of Education Jianghan UniversityWuhan 430074China

The Schrodinger cat state produced differently in two directions is anticipated to be a critical quantum resource in quantum information *** exploring the interplay between quantum nonreciprocity and topology in a one-dimensional microcavity array,we obtain the Schrodinger cat state(a pure quantum state)in a chosen direction at the edge cavity,whereas a classical state in the other *** nonreciprocal generation of the cat state originates from the topologically protected chiralitymode excitation in the nontrivial phase,but in the trivial phase,the nonreciprocal generation of cat state ***,our proposal is switchable by tuning the parameters so that a topological phase transition ***,the obtained cat state has nonreciprocal high fidelity,nonclassicality,and quantum coherence,which are sufficient to be used in various one-way quantum technologies,e.g.,invisible quantum sensing,noise-tolerant quantum computing,and chiral quantum *** work provides a general approach to control quantum nonreciprocities with the topological effect,which substantially broadens the fields of nonreciprocal photonics and topological physics.

关键词： Schr?dinger cat state nonreciprocity topology

维普期刊数据库

Erosion Characteristics of Oil-immersed On-load Tap Changer Contacts Under Varying Contact Speeds and Pressures

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Chinese Journal of Electrical Engineering 2024年第1期10卷 21-34页

作者： Zongying li Shuaibing li Yongqiang Kang Zheng li Hongwei li School of New Energy and Power Engineering Lanzhou Jiaotong UniversityLanzhou 730070China School of Electrical Engineering Southwest Jiaotong UniversityChengdu 611756China School of Automation and Electrical Engineering Lanzhou Jiaotong UniversityLanzhou 730070China

With the growing demand for precise voltage adjustment and reactive regulation,the frequent operation of on-load tap changers(OLTCs)in oil-immersed systems has led to increased erosion of switch contacts by arcs during the switching *** erosion causes significant wear on the contacts,thereby reducing their ***,the present study aims to investigate the behavior and mechanism of arc erosion on contact surfaces in oil-immersed *** achieve this,a self-designed friction and wear test device for OLTC contacts was utilized to conduct experiments at various sliding speeds and contact ***,finite element analysis was employed to validate the experimental results regarding the influence of sliding speed on arc *** surface morphology of the contacts was observed using an optical *** findings revealed that as the sliding speed increased,the arc energy,arc initiation rate,and contact resistance initially exhibited an upward trend,then decreased,and eventually increased *** minimum values were observed at a sliding speed of 90 mm/***,the arc energy,arc initiation rate,and contact resistance decreased gradually as the contact pressure *** reaching a contact pressure of 1.5 N,the variation in the arc energy *** lower contact pressures,arc erosion dominated the wear on the contact ***,at higher contact pressures,the wear transitioned from predominantly arc erosion to a combination of mechanical wear and arc *** summary,experimental and analytical investigations provided insights into the effects of sliding speed and contact pressure on the behavior of arc erosion,contact resistance,and surface damage of OLTC contacts in oil-immersed systems.

关键词： Oil-immersed on-load tap changer arc energy contact resistance friction and wear arc erosion

Alignment efficient image-sentence retrieval considering transferable cross-modal representation learning

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Frontiers of Computer Science 2024年第1期18卷 77-91页

作者： Yang YANG Jinyi GUO Guangyu li Lanyu li Wenjie li Jian YANG School of Computer Science and Engineering Nanjing University of Science and TechnologyNanjing 210094China Department of Computing Hong Kong Polytechnic UniversityHong Kong 100872China State Key Lab.for Novel Software Technology Nanjing UniversityNanjing 210094China 14th Research Institute of China Electronics Technology Group Corporation Nanjing 210094China guangyu.li2017@***

Traditional image-sentence cross-modal retrieval methods usually aim to learn consistent representations of heterogeneous modalities,thereby to search similar instances in one modality according to the query from another modality in *** basic assumption behind these methods is that parallel multi-modal data(i.e.,different modalities of the same example are aligned)can be obtained in *** other words,the image-sentence cross-modal retrieval task is a supervised task with the alignments as ***,in many real-world applications,it is difficult to realign a large amount of parallel data for new scenarios due to the substantial labor costs,leading the non-parallel multi-modal data and existing methods cannot be used *** the other hand,there actually exists auxiliary parallel multi-modal data with similar semantics,which can assist the non-parallel data to learn the consistent ***,in this paper,we aim at“Alignment Efficient Image-Sentence Retrieval”(AEIR),which recurs to the auxiliary parallel image-sentence data as the source domain data,and takes the non-parallel data as the target domain *** single-modal transfer learning,AEIR learns consistent image-sentence cross-modal representations of target domain by transferring the alignments of existing parallel ***,AEIR learns the image-sentence consistent representations in source domain with parallel data,while transferring the alignment knowledge across domains by jointly optimizing a novel designed cross-domain cross-modal metric learning based constraint with intra-modal domain adversarial ***,we can effectively learn the consistent representations for target domain considering both the structure and semantic ***,extensive experiments on different transfer scenarios validate that AEIR can achieve better retrieval results comparing with the baselines.

关键词： image-sentence retrieval transfer learning semantic transfer structure transfer

A hybrid nickel/iron-pyromellitic acid electrocatalyst for oxygen evolution reaction

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Nano Research 2024年第4期17卷 2481-2491页

作者： Guoqi li lin li Wenlong li Fusheng li Chunze Yuan Nian Zhang Hui Zhang Tsu-Chien Weng School of Physical Science and Technology ShanghaiTech UniversityShanghai 201210China Center for Transformative Science ShanghaiTech UniversityShanghai 201210China State Key Lab of Fine Chemicals Institute of Artificial PhotosynthesisDUT-KTH Joint Education and Research Center on Molecular DevicesDalian University of Technology(DUT)Dalian 116024China State Key Laboratory of Functional Materials for Informatics Shanghai Institute of Microsystem and Information TechnologyChinese Academy of SciencesShanghai 200050China

The migration of protons during the oxygen evolution reaction(OER)is a key factor that affects the performance of OER *** enhance proton transportation,we designed a catalyst based on nickel/iron-pyromellitic acid(NiFe-PMA)prepared by the electrochemical deposition *** catalyst exhibited a low overpotential of 188 mV at a current density of 10 mA·cm^(-2),a Tafel slope of 28.2 mV·dec^(-1),and long-term stability for 30 days with a current of 50 mA·cm^(-2).We characterized the NiFe-PMA catalyst using various techniques,including Fourier transform infrared(FTIR)spectroscopy,Raman spectroscopy,X-ray photoelectron spectroscopy(XPS),X-ray absorption spectroscopy(XAS),transmission electron microscopy(TEM),scanning electron microscopy(SEM),and inductively coupled plasma-optical emission spectrometry(ICP-OES).Our results showed that NiFe-PMA contains nickel,iron atoms,and both coordinated and uncoordinated carboxylate ***,XPS data confirmed that carboxylate ligands could adjust the outer electronic structure of metal ions,resulting in the high valence state of Ni in *** result of XAS indicated that the nickel atoms present in the catalyst might be easier to maintain a higher chemical *** investigations using kinetic isotope effects(KIEs)and proton inventory revealed that the uncoordinated carboxylic protons played a crucial role in receiving protons during the OER,which promoted the proton transfer of the rate-determining step of the *** novel electrocatalysts provide a new strategy for designing more active and cost-effective catalysts for the OER.

关键词： nickel/iron-pyromellitic acid oxygen evolution reaction kinetic isotope effects