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Single transition-metal atoms anchored on a novel Diracdispersive π-π conjugated holey graphitic carbon nitride substrate:computational screening toward efficient bifunctional OER/ORR electrocatalysts

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Rare Metals 2024年第8期43卷 3819-3832页

作者： Chun-Yao Fang Xi-Hang Zhang Qiang Zhang Di Liu Xiao-Meng Cui Jing-Cheng Xu Cheng-Long Shi Meng-Yu Yang College of science University of Shanghai for Science and Technology School of Materials and Chemistry University of Shanghai for Science and Technology

Nonprecious-metal-group single-metal-atom catalysts with bifunctional catalytic capabilities toward the oxygen evolution reaction（OER） and oxygen reduction reaction（ORR） are highly sought after in energy-conversion and storage ***,producing renewable and sustainable energy sources remains ***,single-transition metal atoms anchored on π-πconjugated two-dimensional（2D） graphitic carbon nitride substrates form π-d conjugated conductive channels that enhance the overall electrocatalytic ***,firstprinciples calculations were carried out to design and demonstrate a novel macropore graphitic carbon nitride(gC10N3) as a promising 2D electrocatalyst substrate to support single-transition metal（TM,from Sc to Au）.The "donation-acceptance" charge interaction in the TM-N2moiety effectively balances the adsorption strength of oxygenated intermediates in Ni@g-C10N3and Rh@gC10N3,making them effective bifunctional OER/ORR electrocatalysts with IrO2/Pt-beyond overpotentials being as low as 0.39/0.38 V and 0.54/0.44 V,***,they possess high stability and conductivity and are less susceptible to oxidation and corrosion under working *** guarantees high activity under ambient ***,the origin of the OER/ORR activity of TM@g-C10N3is explained using multilevel descriptors:intrinsic(p,Bader charge,integral crystal orbital Hamilton population（ICOHP）,bond length,and d-band center（εd）.In particular,for optimal Ni@g-C10N3,the clear hybridization between the Ni-d orbital and surface O-p orbital causes the paired electrons to occupy the bonding *** enables OH*to be adsorbed on the Ni@g-C10N3,thereby achieving the highest catalytic performance.

关键词： First-principles calculation Oxygen evolution reaction Oxygen reduction reaction Bifunctional electrocatalysts Single-metal-atom electrocatalysts

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Boosted photocatalytic removal of NO using direct Z-scheme UiO-66-NH2/Bi2MoO6 nanoflowers heterojunction:mechanism insight and humidity effect

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Rare Metals 2024年第8期43卷 3758-3770页

作者： Jiang-Yu-Shan Liang Hai-Tao Ren Abdelkader Labidi Qiu-Hui Zhu Qi-Bing Dong Ahmed A.Allam Ahmed Rady Chuan-Yi Wang School of Environmental science and Engineering Shaanxi University of Science and Technology Zoology Department Faculty of ScienceBeni-Suef University Department of Zoology College of ScienceKing Saud University

In practical applications,relative humidity in the air is a key factor affecting the photocatalytic removal of NO,which is often overlooked in previous ***,we developed a direct Z-scheme UiO-66-NH2/Bi2MoO6heterojunction with a nanoflower-like structure to systematically investigate the effect of relative humidity on photocatalytic removal of *** optimized heterojunction for the removal efficiency of NO was 71.6% at1.07 mg·m-3NO concentration（relative humidity=10%）,and the generation of NO2was only 1.1%.Interestingly,with the increase in relative humidity,it showed a higher inhibition effect on NO2,while the removal of NO decreased slightly（8%）,which might be attributed to the affinity effect of NO2with water molecules and the competitive adsorption of H2O and NO on the surface of the heterojunction ***,the reaction pathways of NO removal at the developed heterojunctions were revealed by in situ DRIFTS *** work provides a novel vision for the development of direct Z-scheme heterojunction photocatalysts to effectively remove NO and inhibit the formation of toxic intermediate NO2under different humidities.

关键词： NO removal Relative humidity Direct Z-scheme Bismuth molybdate Visible-light photocatalysis

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Encoding innumerable charge density waves of FeGe into polymorphs of LiFe6Ge6

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science China(Physics,Mechanics & Astronomy) 2024年第9期Mechanics & Astronomy) .卷 130-136页

作者： Yilin Wang School of Emerging Technology University of Science and Technology of China Hefei National Laboratory University of Science and Technology of China New Cornerstone science Laboratory University of Science and Technology of China

Kagome metals exhibit rich quantum states by the intertwining of lattice,charge,orbital and spin degrees of ***,a novel charge density wave （CDW） ground state was discovered in kagome magnet FeGe and was revealed to be driven by lowering magnetic energy via large ***,based on DFTcalculations,we show that such mechanism will yield infinitely many metastable CDWs in FeGe due to different ways to arrange the Ge1-dimerization in enlarged ***,utilizing these metastable CDWs,innumerable polymorphs of kagome magnet LiFe6Ge6can be stabilized by filling Li atoms in the voids right above/below the dimerized Ge1-sites in the CDW *** polymorphs are very stable due to the presence of magnetic-energy-saving mechanism,in sharp contrast to the non-magnetic “166” kagome *** this way,a one-to-one mapping of the metastable CDWs of FeGe to stable polymorphs of LiFe6Ge6is *** one hand,the fingerprints of these metastable CDWs,i.e.,the induced in-plane atomic distortions and band gaps,are encoded into the corresponding stable polymorphs of LiFe6Ge6,such that further study of their properties becomes *** the other hand,such innumerable polymorphs of LiFe6Ge6offer great degrees of freedom to explore the rich physics of magnetic kagome *** thus reveal a novel connection between the unusually abundant CDWs and structural polymorphism in magnetic kagome materials,and establish a new route to obtain structural polymorphism on top of CDW states.

关键词： kagome magnet unconventional charge density wave structural polymorphism magnetic energy saving

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What can we learn from quality assurance badges in open-source software?

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science China(Information sciences) 2024年第4期67卷 146-163页

作者： Feng LI Yiling LOU Xin TAN Zhenpeng CHEN Jinhao DONG Yang LI Xuanzhi WANG Dan HAO Lu ZHANG MoE Key Lab of HCST School of Computer SciencePeking University Department of Computer science Purdue University School of Computer science & Engineering Beihang University(BUAA) Department of Computer science University College London(UCL)

In the development of open-source software(OSS), many developers use badges to give an overview of the software and share some key features/metrics conveniently. Among various badges, quality assurance(QA) badges make up a large proportion and are the most prevalent because QA is of vital importance in software development, and ineffective QA may lead to anomalies or defects. In this paper, we focus on QA badges in open-source projects, which present quality assurance information directly and instantly,and aim to produce some interesting findings and provide practical implications. We collect and analyze 100000 projects written in popular programming languages from GitHub and conduct a comprehensive empirical study both inside and outside QA badges. Inside QA badges, we build a category classification for all QA badges based on the properties they focus on, which shows the types of QA badges developers use. Then,we analyze the frequency of the properties that QA badges focus on, and property combinations, too, which present their use status. We find that QA badges focus on various properties while developers give different preferences to different properties. The use status also differs between different programming languages. For example, projects written in C focus on Security to a great extent. Our findings also provide implications for developers and badge providers. Outside QA badges, we conduct a correlation analysis between QA badges and some software metrics that have potential relationships with code quality, contribution quality, and popularity. We find that QA badges have statistically significant correlations with various software metrics.

关键词： quality assurance badge open-source software code quality empirical study

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A Weakly-Supervised Crowd Density Estimation Method Based on Two-Stage Linear Feature Calibration

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IEEE/CAA Journal of Automatica Sinica 2024年第4期11卷 965-981页

作者： Yong-Chao Li Rui-Sheng Jia Ying-Xiang Hu Hong-Mei Sun the College of Computer science and Engineering Shandong University of Science and TechnologyQingdao 266590 the Faculty of Information science and Engineering Ocean University of ChinaQingdao 266000China the College of Computer science and Engineering Shandong University of Science and TechnologyQingdao 266590China the College of Computer science and Engineering Nanjing University of Science and TechnologyNanjing 210000China

In a crowd density estimation dataset,the annotation of crowd locations is an extremely laborious task,and they are not taken into the evaluation *** this paper,we aim to reduce the annotation cost of crowd datasets,and propose a crowd density estimation method based on weakly-supervised learning,in the absence of crowd position supervision information,which directly reduces the number of crowds by using the number of pedestrians in the image as the supervised *** this purpose,we design a new training method,which exploits the correlation between global and local image features by incremental learning to train the ***,we design a parent-child network(PC-Net)focusing on the global and local image respectively,and propose a linear feature calibration structure to train the PC-Net simultaneously,and the child network learns feature transfer factors and feature bias weights,and uses the transfer factors and bias weights to linearly feature calibrate the features extracted from the Parent network,to improve the convergence of the network by using local features hidden in the crowd *** addition,we use the pyramid vision transformer as the backbone of the PC-Net to extract crowd features at different levels,and design a global-local feature loss function(L2).We combine it with a crowd counting loss(LC)to enhance the sensitivity of the network to crowd features during the training process,which effectively improves the accuracy of crowd density *** experimental results show that the PC-Net significantly reduces the gap between fullysupervised and weakly-supervised crowd density estimation,and outperforms the comparison methods on five datasets of Shanghai Tech Part A,ShanghaiTech Part B,UCF_CC_50,UCF_QNRF and JHU-CROWD++.

关键词： Crowd density estimation linear feature calibration vision transformer weakly-supervision learning

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APF-GAN:Exploring asymmetric pre-training and fine-tuning strategy for conditional generative adversarial network

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Computational Visual Media 2024年第1期10卷 187-192页

作者： Yuxuan Li Lingfeng Yang Xiang Li College of Computer science Nankai UniversityTianjinChina School of Computer science and Engineering Nanjing University of Science and TechnologyNanjingChina

The use of generative adversarial network(GAN)-based models for the conditional generation of image semantic segmentation has shown promising results in recent ***,there are still some limitations,including limited diversity of image style,distortion of detailed texture,unbalanced color tone,and lengthy training *** address these issues,we propose an asymmetric pre-training and fine-tuning(APF)-GAN model.

关键词： tuning network asymmetric

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Practical cloud storage auditing using serverless computing

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science China(Information sciences) 2024年第3期67卷 33-47页

作者： Fei CHEN Jianquan CAI Tao XIANG Xiaofeng LIAO College of Computer science and Software Engineering Shenzhen University College of Computer science Chongqing University

Cloud storage auditing research is dedicated to solving the data integrity problem of outsourced storage on the cloud. In recent years, researchers have proposed various cloud storage auditing schemes using different techniques. While these studies are elegant in theory, they assume an ideal cloud storage model;that is, they assume that the cloud provides the storage and compute interfaces as required by the proposed schemes. However, this does not hold for mainstream cloud storage systems because these systems only provide read and write interfaces but not the compute interface. To bridge this gap, this work proposes a serverless computing-based cloud storage auditing system for existing mainstream cloud object storage. The proposed system leverages existing cloud storage auditing schemes as a basic building block and makes two adaptations. One is that we use the read interface of cloud object storage to support block data requests in a traditional cloud storage auditing scheme. Another is that we employ the serverless computing paradigm to support block data computation as traditionally required. Leveraging the characteristics of serverless computing, the proposed system realizes economical, pay-as-you-go cloud storage auditing. The proposed system also supports mainstream cloud storage upper layer applications(e.g., file preview) by not modifying the data formats when embedding authentication tags for later auditing. We prototyped and open-sourced the proposed system to a mainstream cloud service, i.e., Tencent Cloud. Experimental results show that the proposed system is efficient and promising for practical use. For 40 GB of data, auditing takes approximately 98 s using serverless computation. The economic cost is 120.48 CNY per year, of which serverless computing only accounts for 46%. In contrast, no existing studies reported cloud storage auditing results for real-world cloud services.

关键词： cloud storage auditing serverless computing object storage usability

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Coupling N-doping and confined Co3O4 on carbon nanotubes by polydopamine coating strategy for pleiotropic water purification

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Rare Metals 2024年第7期43卷 3146-3160页

作者： Wen-Long Tu Gang Wang Yue Zhang Hong-Yang Zhu Rong-Rong Du Hong-Yao Zhao Sheng Tang Zeng-Jing Guo Jun Yang Fu Yang Cheng-Zhang Zhu School of Environmental and Chemical Engineering Jiangsu University of Science and Technology School of Chemistry and Chemical Engineering Liaocheng University School of Material science and Engineering Jiangsu University of Science and Technology School of Environmental science and Engineering Nanjing Tech University

The development of effective and sustainable solutions for pleiotropic water purification becomes urgent and *** Fenton-like catalysts for activation of peroxymonosulfate（PMS） to purify organic wastewater show great *** this work,by tuning metal loading with an in-situ polydopamine coating strategy,oxygen vacancy-enriched Co3O4loading on N-doped carbon nanotubes（CNTs） were constructed to enhance PMS activation efficiency for pollutants ***,the obtained modified CNTs afford a well-developed N-containing network structure,which is further endowed with abundant Co（Ⅱ）/Co（Ⅲ） redox cycles and significant metal-carbon *** particular,the surface N doping in CNTs might induce the oriented enrichment of pollutants around the catalyst,which reduces the migration distance and correspondingly improves the utilization of reactive oxidative *** electron transfer efficiency of the catalyst can be further improved by incorporating oxygen vacancy-enriched *** performance results show that the optimal NC/Co-1 could mineralize 20 × 10-6of bisphenol A（BPA） by almost 98% in 8 min.A low reaction activation energy(26.05 kJ·mol-1) in BPA degradation was demonstrated by the NC/*** importantly,NC/Co-1 can inherit excellent degradation performance towards oxytetracycline,2,4-dichlorophenol,and tetracycline,showing wide practical *** addition,by virtue of the photothermal conversion property,NC/Co-1 achieves an additive function for interfacial solar water evaporation(1.84 kg·m-2·h-1,112.51%),showing impressive potential for clean water recovery under complicated environmental pollution conditions.

关键词： Carbon nanotube Advanced oxidation process Co 3 O 4 Photothermal conversion Solar water evaporation

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Symmetric Brownian motor subjected to Lévy noise

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Chinese Physics B 2024年第2期33卷 222-227页

作者：贾考胡兰聂林如 Faculty of science Kunming University of Science and TechnologyKunming 650500China

In the past few years,attention has mainly been focused on the symmetric Brownian motor(BM)with Gaussian noises,whose current and energy conversion efficiency are very ***,we investigate the operating performance of the symmetric BM subjected to Lévy *** numerical simulations,it is found that the operating performance of the motor can be greatly improved in asymmetric Lévy *** any load,the Lévy noises with smaller stable indexes can let the motor give rise to a much greater *** a load,the energy conversion efficiency of the motor can be enhanced by adjusting the stable indexes of the Lévy noises with symmetry *** results of this research are of great significance for opening up BM’s intrinsic physical mechanism and promoting the development of nanotechnology.

关键词： symmetric Brownian motor average velocity energy conversion efficiency Lévy noise

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Blindness-free beam scanning antenna with array of array architecture: principle,design,and experiment

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science China(Information sciences) 2024年第3期67卷 209-224页

作者： Jianxu SUN Yujian CHENG School of Electronic science and Engineering university of Electronic science and Technology of China

This paper presents a 66–76-GHz sparsely-excited phased array antenna with the array of array(Ao A) architecture for eliminating the blindness and suppressing the grating lobe when scanning. For the array antennas printed on the thick dielectric layers with high relative permittivity, scanning blindness appears and seriously impacts the radiation performance. To address this issue, the Ao A topology is developed first. It finds that the scanning blindness appears due to the coupling of the radiating Floquet modes to the non-radiating surface wave(SW) modes. Therefore, the array is divided into two types of domino *** inner-phase distributions are introduced into the domino subarrays to break the one-to-one relationship between the Floquet mode and the SW mode. Then, the blindness inside ±60° scanning volume is eliminated by the aperiodic subarrays. Meanwhile, the aperiodic inner-phase distributions enhance the aperiodicity of the array and contribute to suppressing the grating lobe when scanning. Next, the meta-surface-based dipole with the shorted post is chosen as the unit cell for the proposed aperiodic array. Based on these methods,the array achieves the wide-scanning performance of ±60° in the E-plane and ±30° in the H-plane, without the blindness and the grating lobe. Finally, the 16×16 array is built and simulated with the dimension of32 mm × 32 mm. At the highest operating frequency, the simulated gains are 28.42, 25.17, and 24.01 d Bi when scanning to the broadside, 50° in the E-plane, and 30° in the H-plane, respectively. Compared to the ideal gain, it shows that the simulated radiation efficiency is about 84.13%, 62.08%, and 35.23% when scanning to the broadside, 50° in the E-plane, and 30° in the H-plane, respectively. The worst transmission coefficient, i.e., the worst isolation, is-11.97 d B between the central element and its two adjacent elements in the E-plane. The array prototypes are fabricated, and the experiments are carried out to ver

关键词： 6G communication systems phased array AoA aperiodic subarray wideband wide-scanning surface-wave scanning blindness grating lobe

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