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Meta lab.l.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 lab.l. by incorporating a reweighting strategy into a meta-learning framework. However, it is limited to up or downweighting the contribution of an instance for lab.l.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-lab.l.d data with those of web data and back at the same class are measured. Next, its association probab.l.ty 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-lab.l.d 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： lab.l.associated loss weighting noisy samples fine-grained visual recognition noise-tolerant learning meta-learning

Manipulating fast li_(2)S redox via carbon confinement and oxygen defect engineering of In_(2)O_(3)for lithium-sulfur batteries

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Nano Research 2024年第6期17卷 5179-5187页

作者： Jinlei Qin Rui Wang Zilong Yuan Pei xiao Deli Wang Key laboratory of Material Chemistry for Energy Conversion and Storage Ministry of EducationHubei Key Laboratory of Material Chemistry and Service FailureSchool of Chemistry and Chemical EngineeringHuazhong University of Science and TechnologyWuhan 430074China

lithium-sulfur(li-S)batteries have been considered as promising energy storage systems due to the merits of high energy density and low ***,the lithium polysulfides(liPSs)diffusion and sluggish redox kinetics hamper the battery *** this work,low-bandgap indium oxide(In_(2)O_(3))with dense oxygen vacancies(In_(2)O_(3−x),0bon column(NC)is developed as a desirable liPSs immob.l.zer and promoter to address these intractable *** NC confined In_(2)O_(3−x)with rich O vacancies(In_(2)O_(3−x)@NC)lowers the bandgap of 1.78 eV,strengthens the chemical adsorbab.l.ty to liPSs,and catalyzes the bidirectional li_(2)S *** to the structural and chemical cooperativities,the obtained sulfur electrodes exhibit a stable cycling over 550 cycles at 1.0 C and splendid rate capab.l.ty up to 4.0 *** significantly,when the sulfur-loading reaches as high as 5.5 mg·cm^(−2),the cathodes achieve an areal capacity of 5.12 mAh·cm^(−2)at 0.1 *** strategy of NC confined catalyst with rich defects engineering demonstrates great promise in the development of practical li-S batteries.

关键词： li-S batteries nitrogen-doped carbon confinement oxygen vacancies bidirectional li_(2)S redox

Current-carrying trib.l.gical behavior of C/Cu contact pairs in extreme temperature and humidity environments for railway catenary systems

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Science China(Technological Sciences) 2024年第8期67卷 2537-2548页

作者： SHEN MingXue JI DeHui HU Qiang xiao li lI QiuPing State Key laboratory of Performance Monitoring and Protecting of Rail Transit Infrastructure East China Jiaotong UniversityNanchang 330013China School of Materials Science and Engineering East China Jiaotong UniversityNanchang 330013China Institute of Applied Physics Jiangxi Academy of SciencesNanchang 330095China

Many current-carrying contact pairs, such as those found in pantograph-catenary systems, operate in open environments and are susceptible to significant external interference from temperature and humidity variations. This study investigated the evolution of the friction coefficient and contact resistance of C/Cu contact pairs under alternating temperature, humidity, and current conditions. Through experimentation, the wear rate and microtopography of the worn surface were analyzed under various constant parameters. Subsequently, the differences in trib.l.gical behavior and current-carrying characteristics of the contact pairs under these three parameters were explored. The results revealed that the decrease in temperature resulted in a significant increase in the friction coefficient of the contact pairs, carbon wear, and copper surface roughness. Additionally, the surface oxidation rate was lower at lower temperatures. Moreover, contact resistance did not consistently increase with decreasing temperature, owing to the combined action of the contact area and the oxide film. Compared with temperature, humidity fluctuations at room temperature exerted less influence on the friction coefficient and contact resistance of the contact pairs. Dry environments rendered carbon materials vulnerable to oxidation and cracking, while excessive humidity fostered abrasive wear and arcing. High-current conditions generally degraded the trib.l.gical properties of C/Cu contacts. In the absence of current, the friction coefficient was extremely high, and the copper transfer was high. Under excessive current, copper was susceptible to plowing by carbon micro-bumps and abrasive particles, resulting in a decrease in the friction coefficient. The release of lipids from the carbon surface due to temperature elevation weakened the electrical contact performance and increased the occurrence of arc erosion, thereby exacerbating carbon wear.

关键词： temperature/humidity pantograph-catenary system C/Cu wear current-carrying friction sliding electrical contact

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Crystalline-amorphous M@MN_x(M=Co,Fe,Ni)encapsulated in nitrogen-doped carbon for enhanced efficient and durable hydrogen evolution reaction

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Rare Metals 2024年第4期43卷 1547-1556页

作者： Yang Yang xiao-Chuan Duan Shao-Hui Guo Xian-Ming Zhang College of Materials Science and Engineering College of ChemistryKey Laboratory of Interface Science and Engineering in Advanced MaterialsTaiyuan University of TechnologyYuci030600China

Developing earth-abundant electrocatalysts for hydrogen evolution reaction(HER)is important for the sustainable energy ***,efficient and stable heterocatalysts consisting of crystalline-amorphous M@MN_(x)(M=Co,Fe,Ni)encapsulated in N-doped carbon layers supported with N-doped graphene sheets(denoted as M@MN_(x)@NC-NG)are synthesized by facile hydrothermal reaction and nitridation *** the nitriding process,metal ions in M(tzbc)_2(H_(2)O)_4(tzbc=4-(1H-1,2,4-triazol-1-yl)benzoic acid)complexes are reduced to crystalline M cores,accompanied by the formation of amorphous MN_(x)shells;the tzbc ligands are insitu carbonized to form outermost N-doped carbon(NC)layers that connect with inner MN_(x)via M-N-C motifs inherited from the complex precursors and inhibit the transition of MN_(x)from amorphous to crystalline *** Co@CoN_(x)@NC-NG catalyst exhibits excellent HER activity with small overpotentials of 45 and 64 mV at a cathode current density of 10 mA·cm^(-2)and low Tafel slopes of 40 and 85 mV·dec^(-1)in 0.5 mol·l^(-1)H_(2)SO_4 and1.0 mol·l^(-1)KOH electrolytes,*** Co@CoN_(x)@NC-NG retains 97%of the initial overpotential after 100,000 s in both acidic and alkaline *** outstanding HER performance originates from the crystalline-amorphous Co@CoN_(x)that redistributes electrons around the heterointerfaces,facilitating the conversion process of H^(+)/H_(2)O to hydrogen and thereby promoting HER *** outermost NC layers serve as the armor of Co@CoN_(x),and graphene nanosheets act as carriers of egg-like Co@CoN_(x)@NC and conduction paths for electron shuttles,ensuring stable and continuous electrocatalytic hydrogen production.

关键词： Hydrogen evolution reaction Electrocatalysts Iron group metals Heterojunction Crystalline-amorphous structure

Ramsey Numbers of Trees Versus Multiple Copies of books

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Acta Mathematicae Applicatae Sinica 2024年第3期40卷 600-612页

作者： xiao-bing GUO Si-nan HU Yue-jian PENG School of Mathematical Sciences Luoyang Normal UniversityLuoyang 471934China School of Mathematics Hunan UniversityChangsha 410082China

Given two graphs G and H,the Ramsey number R(G,H) is the minimum integer N such that any two-coloring of the edges of K_(N) in red or blue yields a red G or a blue *** v(G) be the number of vertices of G and χ(G) be the chromatic number of *** s(G) denote the chromatic surplus of G,the number of vertices in a minimum color class among all proper χ(G)-colorings of *** showed that R(G,H)≥(v(G)-1)(χ(H)-1)+s(H) if G is connected and v(G)≥s(H).A connected graph G is H-good if R(G,H)=(v(G)-1)(χ(H)-1)+s(H).let tH denote the disjoint union of t copies of graph H,and let G∨H denote the join of G and *** a complete graph on n vertices by K_(n),and a tree on n vertices by T_(n).Denote a book with n pages by b_(n),i.e.,the join K_(2) ∨■.Erd?s,Faudree,Rousseau and Schelp proved that T_(n) is b_(m)-good if n≥*** this paper,we obtain the exact Ramsey number of T_(n) versus 2b_(2).Our result implies that T_(n) is 2b_(2)-good if n≥5.

关键词： ramsey number ramsey goodness tree book

Functionalization of cellulose carbon dots with different elements(N,b and S)for mercury ion detection and anti-counterfeit applications

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Chinese Chemical letters 2024年第7期35卷 355-359页

作者： xiaoning li Quanyu Shi Meng li Ningxin Song Yumeng xiao Huining xiao Tony D.James lei Feng Second Affiliated Hospital of Dalian Medical University Dalian 116023China Hebei Key lab of Power Plant Flue Gas Multi-Pollutants Control Department of Environmental Science and EngineeringNorth China Electric Power UniversityBaoding 071003China Department of Chemical Engineering and limerick Pulp&Paper Centre University of New Brunswick15 Dineen DriveFredericton NB E3B 5A3Canada Department of Chemistry University of BathBath BA27AYUnited Kingdom School of Chemistry and Chemical Engineering Henan Normal UniversityXinxiang 453007China

Mercury ion(Hg^(2+)),as one of the most toxic heavy metal ions,accumulates easily in the environment,which can generate potential hazards to the ecosystem and human *** effectively detect and remove Hg^(2+),we fabricated four types of carbon dots(CDs)using carboxymethyl nanocellulose as a carbon source doped with different elements using a hydrothermal *** the CDs exhibited a strong fluorescence emission,excitation-dependent emission and possessed good water ***,the four fluorescent CDs were used for Hg^(2+)recognition in aqueous solution,where the CDs-N exhibited better sensitivity and selectivity for Hg^(2+)detection,with a low limit of detection of 8.29×10^(-6)mol/*** was determined that the fluorescence quenching could be ascribed to a photoinduced charge-transfer processes between Hg^(2+)and the *** addition,the CDs-N were used as a smart invisible ink for anticounterfeiting,information encryption and ***,the CDs-N were immersed into a cellulose(CMC)-based hydrogel network to prepare fluorescent hydrogels capable of simultaneously detecting and adsorbing Hg^(2+).We anticipate that this research will open possib.l.ties for a green method to synthesize fluorescent CDs for metal ion detection and fluorescent ink production.

关键词： Carbon dots Functional groups Hg^(2+)detection Mechanism Anti-counterfeiting

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Associations between Geriatric Nutrition Risk Index,bone mineral density and body composition in type 2 diabetes patients

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World Journal of Diabetes 2024年第3期15卷 403-417页

作者： xiao-xiao Zhu Kai-Feng Yao Hai-Yan Huang li-Hua Wang Department of Pediatrics The Second Affiliated Hospital of Nantong UniversityFirst People’s Hospital of Nantong CityNantong 226001Jiangsu ProvinceChina Department of Nursing The Second Affiliated Hospital of Nantong UniversityFirst People’s Hospital of Nantong CityNantong 226001Jiangsu ProvinceChina Department of Endocrinology The Second Affiliated Hospital of Nantong UniversityFirst People’s Hospital of Nantong CityNantong 226001Jiangsu ProvinceChina

bACKGROUND Type 2 diabetes mellitus(T2DM),a fast-growing issue in public health,is one of the most common chronic metab.l.c disorders in older *** and sarcopenia are highly prevalent in T2DM patients and may result in fractures and *** people with T2DM,the association between nutrition,sarcopenia,and osteoporosis has rarely been *** To evaluate the connections among nutrition,bone mineral density(bMD)and body composition in patients with *** We enrolled 689 patients with T2DM for this cross-sectional *** patients underwent dual energy X-ray absorptiometry(DXA)examination and were categorized according to baseline Geriatric Nutritional Risk Index(GNRI)values calculated from serum albumin levels and body *** GNRI was used to evaluate nutritional status,and DXA was used to investigate bMD and body *** forward linear regression analysis was used to identify the factors associated with bMD and skeletal muscle mass *** Of the total patients,394 were men and 295 were *** with patients in tertile 1,those in tertile 3 who had a high GNRI tended to be younger and had lower HbA1c,higher bMD at all bone sites,and higher appendicular skeletal muscle index(ASMI).These important trends persisted even when the patients were divided into younger and older *** GNRI was positively related to ASMI(men:r=0.644,Pl body fat(men:r=0.453,PbMD at all bone sites,lumbar spine(l1-l4)bMD(men:r=0.110,P=0.029;women:r=0.256,PbMD(men:r=0.293,PbMD(men:r=0.358,Plinical parameters,the GNRI was still significantly associated with bMD at the lumbar spine and femoral ***,a low lean mass index and higherβ-collagen special sequence were associated with low bMD at all bone *** was negatively correlated with

关键词： Geriatric Nutrition Risk Index bone mineral density Skeletal muscle mass Type 2 diabetes

Feature Matching via Topology-Aware Graph Interaction Model

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IEEE/CAA Journal of Automatica Sinica 2024年第1期11卷 113-130页

作者： Yifan lu Jiayi Ma xiaoguang Mei Jun Huang xiao-Ping Zhang the Electronic Information School Wuhan UniversityWuhan 430072China IEEE Tsinghua berkeley Shenzhen Institute Shenzhen 518071China the Department of Electrical Computer and Biomedical EngineeringToronto Metropolitan UniversityToronto ON M5B 2K3Canada

Feature matching plays a key role in computer vision. However, due to the limitations of the descriptors, the putative matches are inevitably contaminated by massive *** paper attempts to tackle the outlier filtering problem from two aspects. First, a robust and efficient graph interaction model,is proposed, with the assumption that matches are correlated with each other rather than independently distributed. To this end, we construct a graph based on the local relationships of matches and formulate the outlier filtering task as a binary lab.l.ng energy minimization problem, where the pairwise term encodes the interaction between matches. We further show that this formulation can be solved glob.l.y by graph cut algorithm. Our new formulation always improves the performance of previous localitybased method without noticeable deterioration in processing time,adding a few milliseconds. Second, to construct a better graph structure, a robust and geometrically meaningful topology-aware relationship is developed to capture the topology relationship between matches. The two components in sum lead to topology interaction matching(TIM), an effective and efficient method for outlier filtering. Extensive experiments on several large and diverse datasets for multiple vision tasks including general feature matching, as well as relative pose estimation, homography and fundamental matrix estimation, loop-closure detection, and multi-modal image matching, demonstrate that our TIM is more competitive than current state-of-the-art methods, in terms of generality, efficiency, and effectiveness. The source code is publicly available at http://***/Yifanlu2000/TIM.

关键词： Feature matching graph cut outlier filtering topology preserving

多逻辑比特表面码结构设计及其逻辑CNOT门实现

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物理学报 2024年第4期73卷 47-59页

作者：权东晓吕晓杰张雯菲西安电子科技大学通信工程学院西安710071 西安电子科技大学量子信息协同创新中心西安710071

量子计算因具有并行处理能力,相比于经典计算有着指数级的加速,但量子系统具有脆弱性,极易受到噪声的影响,量子纠错码是克服量子噪声的有效手段.量子表面码是一种拓扑稳定子码,由于其结构上的最近邻居特点和较高的容错阈值,表面码在大... 详细信息

量子计算因具有并行处理能力,相比于经典计算有着指数级的加速,但量子系统具有脆弱性,极易受到噪声的影响,量子纠错码是克服量子噪声的有效手段.量子表面码是一种拓扑稳定子码,由于其结构上的最近邻居特点和较高的容错阈值,表面码在大规模容错量子计算方面具有巨大的潜力.目前已有的基于边界的表面码均为编码一个逻辑比特的表面码,本文主要研究基于边界如何实现多逻辑量子比特的编码,包括设计表面码的结构,根据结构找出对应的稳定子和逻辑操作,进一步根据稳定子设计出基于稳定子实现的编码线路;在研究基于测量和纠正的单量子比特间CNOT实现原理和基于融合操作和分割操作的单逻辑量子比特表面码间CNOT门实现原理的基础上,优化了基于融合操作和分割操作的单逻辑量子比特表面码间CNOT门实现方案,将其扩展到所设计的多逻辑量子比特表面码上实现了多逻辑量子比特表面码之间的CNOT操作,并通过仿真验证量子线路的正确性.本文设计的多逻辑比特表面码克服了单比特表面码不能密铺于量子芯片的缺点且提高了某些逻辑操作的长度,提高了容错能力.基于联合测量的思想降低了对辅助比特的要求且减小了实现过程中对量子资源的需求.

关键词：量子表面码多逻辑比特编码逻辑CNOT门融合操作分割操作