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Carbon nanofibers embedded with Fe-Co alloy nanoparticles via electrospinning as lightweight high-performance electromagnetic wave absorbers

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Rare Metals 2024年第6期43卷 2769-2783页

作者： Wen-Jun Cai Jian-Guo Jiang Zi-Dong zhang Zi-Xuan Liu Lu-Jiezhang Zhen-kun Long Ke Bi Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials(Ministry of Education) Shandong UniversityJinan 250061China School of Materials Science and Engineering Shandong UniversityJinan 250061China Energy Institute Qilu University of Technology(Shandong Academy of Sciences)Jinan 250014China State Key Laboratory of Information Photonics and Optical Communications School of ScienceBeijing University of Posts and TelecommunicationsBeijing 100876China

As a lot of electromagnetic pollution and interference issues have emerged,to overcome electromagnetic interference,prevent electromagnetic hazards,and develop new high-performance electromagnetic wave(EMW)absorbers have become a significant task in the field of materials *** this paper,a three-dimensional(3D)carbon nanofibers network with core-shell structure,embedded with varied molar ratios of iron and cobalt(4:0,3:1,2:2,1:3,0:4),was effectively synthesized(Fe/Co@C-CNFs)via *** phase,microstructure,magnetic and EMW absorption properties were *** is discovered that Fe/Co@C-CNFs doped with iron:cobalt=1:1 have excellent EMW absorption *** the matching thickness is 1.08 mm,the minimum reflection loss(RL)value is-18.66 dB,while the maximum effective absorption bandwidth(EAB)reaches 4.2 GHz(13.9-18 GHz)at a thickness of 1.22 *** is owing to the absorbers'superior impedance matching and multiple reflections as well as the conductivity,dielectric,and magnetic losses of carbon nanofibers embedded with Fe-Co alloy *** addition,the radar cross section(RCS)of the absorbers has been calculated by CST Studio Suite,showing that the absorbing coating can effectively reduce the RCS at various angles,especially for Fe/Co@C-CNFs doped with iron:cobalt=1:*** findings not only provide new insights for the preparation of light-weight and high-performance electromagnetic wave absorbers,but also contribute to energy storage and conversion.

关键词： Electromagnetic wave(EMW)absorbers Fe/Co@C-CNFs Core-shell structure EMW absorbing mechanism Radar cross section(RCS)

MOF-Derived Iron-Cobalt Phosphide Nanoframe as Bifunctional Electrocatalysts for Overall Water Splitting

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Energy & Environmental Materials 2024年第6期7卷 312-320页

作者： Yanqi Yuan kun Wang Boan Zhong Dongkun Yu Fei Ye Jing Liu Joydeep Dutta Peng zhang School of Materials Science and Engineering Shanghai Jiao Tong University800 Dongchuan RoadShanghai 200240China Functional NanoMaterials Group Department of Applied PhysicsSchool of Engineering SciencesKTH Royal Institute of TechnologyHannes Alfv´ens v¨ag 1211419StockholmSweden Shanghai Key Laboratory of Hydrogen Science Shanghai 200240China

Transition metal phosphides(TMPs)have emerged as an alternative to precious metals as efficient and low-cost catalysts for water *** doping and morphology control are effective approaches to further improve the performance of ***,Fe-doped CoP nanoframes(Fe-CoP NFs)with specific open cage configuration were designed and *** unique nano-framework structured Fe-CoP material shows overpotentials of only 255 and 122 mV at 10 mA cm^(−2)for oxygen evolution reaction(OER)and hydrogen evolution reaction(HER),respectively,overwhelming most transition metal *** overall water splitting,the cell voltage is 1.65 V for Fe-CoP NFs at a current density of 10 mA cm^(−2),much superior to what is observed for the classical nanocubic ***-CoP NFs show no activity degradation up to 100 h which contrasts sharply with the rapidly decaying performance of noble metal catalyst *** superior electrocatalytic performance of Fe-CoP NFs due to abundant accessible active sites,reduced kinetic energy barrier,and preferable*O-containing intermediate adsorption is demonstrated through experimental observations and theoretical *** findings could provide a potential method for the preparation of multifunctional material with hollow structures and offer more hopeful prospects for obtaining efficient earth-abundant catalysts for water splitting.

关键词： electrocatalysis hollow structure iron-doped cobalt phosphide MOF overall water splitting

Photoredox-Catalyzed Metal-Free Regio-&Stereoselective C(sp^(2))-H Amination of Enamides with N-Aminopyridium Salts

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Chinese Journal of Chemistry 2024年第18期42卷 2235-2242页

作者： Zheng-Bao Qin kun Ni Li Wang Xiao-Di Wu Yu zhang Kai Zhao Institute of Advanced Synthesis School of Chemistry and Molecular EngineeringJiangsu National Synergetic Innovation Center for Advanced MaterialsNanjing Tech UniversityNanjingJiangsu211816China college of Chemical Engineering Nanjing Forestry UniversityNanjingJiangsu 210037China

A visible-light-induced photoredox-catalyzed regioselective and stereoselective C(sp')-H amination of enamides with bench-stable and A visible-light-induced photoredox-catalyzed regioselective and stereoselective C(sp)-H amination of enamides with bench-stable and easily accessible N-aminopyridium salts is developed,affording synthetically and biologically prominent vicinal 1,2-diamine scaffolds with broad substrate scope and excellent functional group *** transformation proceeded through a radical pathway involving the Giese addition of the relatively electrophilic N-centered sulfonamidyl radical species to nucleophilicβ-olefinic position of enamides followed by the ensuing single electron oxidation andβ-H elimination,delivering geometrically-defined Z-configuredβ-sulfonamidylated *** operational simplicity,environmental friendliness and cost efficiency of this methodology allowed it to pave a new avenue to enrich the arsenal of synthetically crucial functionalized enamides and their related derivatives.

关键词： Enamides Amination Photoredox catalysis Regioselective Stereoselective Metal-free

Ada-FFL:Adaptive computing fairness federated learning

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CAAI Transactions on Intelligence Technology 2024年第3期9卷 573-584页

作者： Yue Cong Jing Qiu kun zhang Zhongyang Fang Chengliang Gao Shen Su Zhihong Tian The Cyberspace Institute of Advanced Technology Guangzhou UniversityGuangzhouChina Pengcheng Lab ShenzhenChina Carnegie Mellon University PittsburghPennsylvaniaUSA Mohamed Bin Zayed University of Artificial Intelligence Abu DhabiUnited Arab Emirates

As the scale of federated learning expands,solving the Non-IID data problem of federated learning has become a key challenge of *** existing solutions generally aim to solve the overall performance improvement of all clients;however,the overall performance improvement often sacrifices the performance of certain clients,such as clients with less *** fairness may greatly reduce the willingness of some clients to participate in federated *** order to solve the above problem,the authors propose Ada-FFL,an adaptive fairness federated aggregation learning algorithm,which can dynamically adjust the fairness coefficient according to the update of the local models,ensuring the convergence performance of the global model and the fairness between federated learning *** integrating coarse-grained and fine-grained equity solutions,the authors evaluate the deviation of local models by considering both global equity and individual equity,then the weight ratio will be dynamically allocated for each client based on the evaluated deviation value,which can ensure that the update differences of local models are fully considered in each round of ***,by combining a regularisation term to limit the local model update to be closer to the global model,the sensitivity of the model to input perturbations can be reduced,and the generalisation ability of the global model can be *** numerous experiments on several federal data sets,the authors show that our method has more advantages in convergence effect and fairness than the existing baselines.

关键词： adaptive fariness aggregation fairness federated learning non-IID

Design and Implementation of NOMA Backscatter Communication with Low-Precision Oscillators

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Journal of Communications and Information Networks 2024年第3期9卷 286-295页

作者： kun zhang Zhongye Cao Huixin Dong Zhiqing Luo Luanjian Bian Wei Wang School of Electronic Information and Communications Huazhong University of Science and TechnologyWuhan 430074China ZTE Corporation Shenzhen 518057China

Recent years have witnessed increasing demands for the large-scale deployment of Internetof-things(IoT)*** technologies are promising to meet these demands with the notable low power consumption and ***,the conventional designs of backscatter prioritize energy efficiency at the cost of multiple access schemes with low spectral efficiency,which hinders its large-scale *** this paper,we propose a new non-orthogonal multiple access backscatter(NOMA-Backscatter)system to meet high spectral-efficiency *** implement the NOMA-Backscatter system for the first time with resource-constrained low-cost and low-power hardware and eliminate the affects of unstable oscillators during the successive interference cancellation(SIC)demodulation process in real *** demonstrate that NOMA-Backscatter can achieve 1.38 Mbit/s throughput with 200%tag load,and the spectral efficiency is 1.73×higher than state-of-the-art backscatter systems.

关键词： backscatter communication NOMA spectral efficiency multiple access

Molecular insights into self-incompatibility systems:From evolution to breeding

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Plant Communications 2024年第2期5卷 23-45页

作者： Diyang zhang Yuan-Yuan Li Xuewei Zhao Cuili zhang Ding-kun Liu Siren Lan Weilun Yin Zhong-Jian Liu Key Laboratory of National Forestry and Grassland Administration for Orchid Conservation and Utilization Fujian Agriculture and Forestry UniversityFuzhou 350002China College of Forestry Fujian Agriculture and Forestry UniversityFuzhou 350002China College of Biological Sciences and Technology Beijing Forestry UniversityBeijing 100083China

Plants have evolved diverse self-incompatibility(SI)systems for *** Darwin’s time,consid-erable progress has been made toward elucidating this unrivaled reproductive *** advances in interdisciplinary studies and applications of biotechnology have given rise to major break-throughs in understanding the molecular pathways that lead to SI,particularly the strikingly different SI mechanisms that operate in Solanaceae,Papaveraceae,Brassicaceae,and *** best-un-derstood SI systems,together with discoveries in other"nonmodel"SI taxa such as Poaceae,suggest a complex evolutionary trajectory of SI,with multiple independent origins and frequent and irreversible *** exploration of self-/nonself-discrimination signaling cascades has revealed a compre-hensive catalog of male and female identity genes and modifier factors that control *** also enable the characterization,validation,and manipulation of SI-related factors for crop improvement,helping to address the challenges associated with development of inbred ***,we review current knowledge about the evolution of SI systems,summarize key achievements in the molecular basis of pol-len‒pistil interactions,discuss potential prospects for breeding of SI crops,and raise several unresolved questions that require further investigation.

关键词： self-incompatibility S-RNase evolution genome editing crop improvement

Dating Kimberlite Using Apatite U-Pb Geochronology: A Case Study from Diamond-Bearing Dikes in South China

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Journal of Earth Science 2024年第3期35卷 1059-1062页

作者： Jiawei zhang Huan Wang Defeng He Yuhua Zhu kun Wang Yuan Qiu Guizhou Geological Survey Bureau of Geology and Mineral Exploration and Development of Guizhou ProvinceGuiyang 550081China College of Resources and Environmental Engineering Guizhou UniversityGuiyang 550025China Yanduzhongshi Geological Analysis Laboratory Ltd. Beijing 100080China State Key Laboratory of Ore Deposit Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China

Kimberlite,one of the deepest known magmatic rocks on Earth,offers valuable glimpses into the deep mantle composition(Woodhead et al.,2019),craton structure(Gardiner et al.,2020),global geodynamic variation(Tappe et al.,2018),and diamond formation(Giuliani et al.,2023).The accurate determination of the emplacement of this special rock is crucial for revealing such ***,dating kimberlite is challenging due to its silica-poor,volatile-rich,strongly altered,and hybrid nature(Mitchell et al.,2019).Zircon is unsuitable for dating kimberlite and related rocks due to its preference for crystallizing in intermediate to felsic melts(Gervasoni et al.,2016)rather than silica-poor *** if present,zircon is prone to Pb loss through hydrothermal alteration(Zi et al.,2022)in a volatile-rich system like kimberlitic magmas.

关键词： dating magma alteration

Human radiological safety assessment for petawatt laser-driven ion acceleration experiments in CLAPA-T

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Matter and Radiation at Extremes 2024年第4期9卷 8-15页

作者： Xiaopeng zhang Jiarui Zhao Shengxuan Xu Xun Chen Ying Gao Shiyou Chen kun Zhu Xueqing Yan Wenjun Ma State Key Laboratory of Nuclear Physics and Technology and Key Laboratory of HEDP of the Ministry of EducationCAPTPeking UniversityBeijing 100871China Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsCASBeijing 100049China Beijing Laser Acceleration Innovation Center HuairouBeijing 101400China Institute of Guangdong Laser Plasma Technology BaiyunGuangzhou 510540China

The newly built Compact Laser Plasma Accelerator-Therapy facility at Peking University will deliver 60 J/1 Hz laser pulses with 30 fs *** by this petawatt laser facility,proton beams with energy up to 200 MeV are expected to be generated for tumor *** high-repetition operation,both prompt radiation and residual radiation may cause safety ***,human radiological safety assessment before commissioning is *** this paper,we simulate both prompt and residual radiation using the Geant4 and FLUKA Monte Carlo codes with reasonable proton and as-produced electron beam *** find that the prompt radiation can be shielded well by the concrete wall of the experimental hall,but the risk from residual radiation is nonnegligible and necessitates adequate radiation *** the basis of the simulation results,we discuss the constraints imposed by radiation safety considerations on the annual working time,and we propose radiation cooling strategies for different shooting modes.

关键词： laser prompt acceleration

Study on the fast elimination of smoke particle based on electro-acoustic coupling agglomeration technology

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Particuology 2024年第5期88卷 1-10页

作者： Jie Feng Mingfeng Lu Kaige Wang kun Luo Mingzhou Yu Guangxue zhang Jiangrong Xu Shuping Pan Hailin Gu The Institute for Energy Engineering China Jiliang UniversityHangzhou310018China State Key Laboratory of Clean Energy Utilization Zhejiang UniversityHangzhou310027China Qingshanhu Energy Research Center Zhejiang UniversityHangzhou310017China Zhejiang Ecological Environment Monitoring Center Hangzhou310012China

Fire smoke,which consists large amounts of fine particles,is considered as the fatal factor in *** this study,a fast smoke particle elimination method based on electro-acoustic coupling agglomeration technology is ***,the experimental results show that the electro-acoustic coupling agglomeration has higher smoke elimination efficiency compared to *** smoke transmission is much less than 80%after 30s of single acoustic or electric field action,while the coupled field reaches 90%.Then,the effects of acoustic frequency,sound pressure level and voltage on the smoke elimination characteristics are *** is found that the optimal acoustic frequency is *** as the sound pressure level and voltage increase,the elimination efficiency first increases and then tends to stabilize,the critical values of the sound pressure level and voltage are 135 dB and *** indicates that there is an optimal combination of the three ***,through the theoretical analysis of particle movement and the micro-morphology of agglomerates,the particle agglomeration mechanism under the electro-acoustic coupling is *** study provides a new idea for the fast elimination of fire smoke particle.

关键词： Smoke particle Agglomeration Electro-acoustic coupling Smoke elimination