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Preparation of CIP@TiO_(2) composite with broadband electromagnetic wave absorption properties

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International Journal of Minerals,Metallurgy and Materials 2024年第1期31卷 197-205页

作者： Qiang Su Hanqun Wang Yunfei He Dongdong Liu Xiaoxiao Huang Bo Zhong school of Materials science and Engineering Harbin Institute of TechnologyWeihaiWeihai 264209China school of Materials science and Engineering Harbin Institute of TechnologyHarbin 150001China

Scholars aim for the improved impedance matching (Z) of materials while maintaining their excellent wave absorption properties. Based on the hydrolysis characteristics of isopropyl titanate, a simple preparation process for the coating of carbonyl iron powder(CIP) with TiO_(2) was designed. Given the TiO2coating, the Z of the CIP@TiO_(2) composite was adjusted well by decreasing the dielectric constant. Moreover, the interfacial polarization of CIP@TiO_(2) was enhanced. Ultimately, the electromagnetic-wave (EMW) absorption property of the CIP@TiO_(2)composite was improved substantially, the minimum reflection loss reached-46.07 dB, and the effective absorption bandwidth can reach 8 GHz at the composite thickness of 1.5 mm. Moreover, compared with CIP, the oxidation resistance of CIP@TiO_(2)showed remarkable improvement. The results revealed that the oxidation starting temperature of CIP@TiO_(2) as about 400℃,whereas the uncoated CIP had an oxidation starting temperature of approximately 250℃. Moreover, the largest oxidation rate temperature of CIP@TiO_(2) increased to around 550℃. This work opens up a novel strategy for the production of high-performance EMW absorbers via structural design.

关键词： carbonyl iron@titanium dioxide electromagnetic-wave absorption impedance matching oxidation resistance

The role of strain in oxygen evolution reaction

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Journal of Energy Chemistry 2024年第6期93卷 322-344,I0009页

作者： Zihang Feng Chuanlin Dai Zhe Zhang Xuefei Lei Wenning Mu Rui Guo Xuanwen Liu Junhua You school of Materials science and Engineering Northeastern UniversityShenyang 110819LiaoningChina school of Materials science and technology Shenyang University of TechnologyShenyang 110870LiaoningChina

The oxygen evolution reaction(OER)is a crucial step in metal-air batteries and water splitting technologies,playing a significant role in the efficiency and achievable heights of these two ***,the OER is a four-step,four-electron reaction,and its slow kinetics result in high overpotentials,posing a *** address this issue,numerous strategies involving modified catalysts have been proposed and proven to be highly *** these strategies,the introduction of strain has been widely reported because it is generally believed to effectively regulate the electronic structure of metal sites and alter the adsorption energy of catalyst surfaces with reaction ***,strain has many other effects that are not well known,making it an important yet unexplored *** on this,this review provides a detailed introduction to the various roles of strain in *** better explain these roles,the review also presents the definition of strain and elucidates the potential mechanisms of strain in OER based on the d-band center theory and adsorption volcano ***,the review showcases various ways of introducing strain in OER through examples reported in the latest literature,aiming to provide a comprehensive perspective for the development of strain ***,the review analyzes the appropriate proportion of strain introduction,compares compressive and tensile strain,and examines the impact of strain on *** the review offers prospects for future research directions in this emerging field.

关键词： Oxygen evolution reaction Strain generation Tensile strain Compressive strain Strain mechanism Strain effects

Single-photon scattering and quantum entanglement of two giant atoms with azimuthal angle differences in a waveguide system

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Chinese Physics B 2024年第5期33卷 337-342页

作者：黄劲松黄红武李艳玲徐中辉 school of Information Engineering Jiangxi University of Science and TechnologyGanzhou 341000China Faculty of science Jiangxi University of Science and TechnologyGanzhou 341000China

We theoretically investigate coherent scattering of single photons and quantum entanglement of two giant atoms with azimuthal angle differences in a waveguide *** the real-space Hamiltonian,analytical expressions are derived for the transport spectra scattered by these two giant atoms with four azimuthal ***-like resonance can be exhibited in the scattering spectra by adjusting the azimuthal angle *** concurrence of the entangled state for two atoms can be implemented in a wide angle-difference range,and the entanglement of the atomic states can be switched on/off by modulating the additional azimuthal angle differences from the giant *** suggests a novel handle to effectively control the single-photon scattering and quantum entanglement.

关键词： quantum transport quantum entanglement scattering theory optical waveguide

Single transition-metal atoms anchored on a novel Diracdispersiveπ-πconjugated 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 TechnologyShanghai 200093China school of Materials and Chemistry University of Shanghai for Science and TechnologyShanghai 200093China

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 onπ-πconjugated two-dimensional(2D)graphitic carbon nitride substrates formπ-d conjugated conductive channels that enhance the overall electrocatalytic ***,firstprinciples calculations were carried out to design and demonstrate a novel macropore graphitic carbon nitride(gC_(10)N_(3))as a promising 2D electrocatalyst substrate to support single-transition metal(TM,from Sc to Au).The"donation-acceptance"charge interaction in the TM-N_(2)moiety effectively balances the adsorption strength of oxygenated intermediates in Ni@g-C_(10)N_(3)and Rh@gC_(10)N_3,making them effective bifunctional OER/ORR electrocatalysts with IrO_(2)/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-C_(10)N_(3) is 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-C_(10)N_(3),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-C_(10)N_(3),thereby achieving the highest catalytic performance.

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

A strategy to synthesize phosphorus-containing nickel phyllosilicate whiskers to enhance the flame retardancy of epoxy composites with excellent mechanical and dry-friction properties

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Frontiers of Chemical science and Engineering 2024年第3期18卷 39-50页

作者： Shibin Nie Zongquan Zhao Yuxuan Xu Wei He Wenli Zhai Jinian Yang school of Public Security and Emergency Management Anhui University of Science and TechnologyHefei231131China school of Safety science and Engineering Anhui University of Science and TechnologyHuainan232001China school of Materials science and Engineering Anhui University of Science and TechnologyHuainan232001China Institute of Energy Hefei Comprehensive National Science CenterHefei230000China

To enhance the fire safety and wear resistance of epoxy,phosphorus-containing nickel phyllosilicate whiskers(FP-NiPS)were synthesized using a facile hydrothermal technology,with 9,10-dihydro-9-oxa-10-phosphaphenanthrene as the organic *** impacts of FP-NiPS on the thermal stability,flame retardancy,and mechanical and tribological properties of EP composites were *** findings demonstrated that 5 wt%FP-NiPS elevated the limiting oxygen index of the EP composite from 23.8%to 28.4%,achieving a V-0 rating during vertical burning ***-NiPS could enhance the thermal stability of epoxy resin(EP)and facilitate the development of a dense and continuous carbon layer,thereby significantly improving the fire safety of the EP *** FP-NiPS led to an 8.2%increase in the tensile strength and a 38.8%increase in the elastic modulus of the EP composite,showing outstanding mechanical ***,FP-NiPS showed remarkable potential in enhancing the wear resistance of *** wear rate of 1 wt%FP-NiPS is 2.34×10^(−5) mm^(3)·N^(−1)·m^(−1),a decrease of 66.7%compared to *** work provides a novel promising modification method to enhance the fire safety,mechanical and wear resistance properties of EP.

关键词： nickel phyllosilicate epoxy resin flame retardant wear resistance mechanical property

YOLOv5ST:A Lightweight and Fast Scene Text Detector

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Computers, Materials & Continua 2024年第4期79卷 909-926页

作者： Yiwei Liu Yingnan Zhao Yi Chen Zheng Hu Min Xia school of Computer and science Nanjing University of Information Science and TechnologyNanjing210044China school of Automation Nanjing University of Information Science and TechnologyNanjing210044China

Scene text detection is an important task in computer *** this paper,we present YOLOv5 Scene Text(YOLOv5ST),an optimized architecture based on YOLOv5 v6.0 tailored for fast scene text *** primary goal is to enhance inference speed without sacrificing significant detection accuracy,thereby enabling robust performance on resource-constrained devices like drones,closed-circuit television cameras,and other embedded *** achieve this,we propose key modifications to the network architecture to lighten the original backbone and improve feature aggregation,including replacing standard convolution with depth-wise convolution,adopting the C2 sequence module in place of C3,employing Spatial Pyramid Pooling Global(SPPG)instead of Spatial Pyramid Pooling Fast(SPPF)and integrating Bi-directional Feature Pyramid Network(BiFPN)into the *** results demonstrate a remarkable 26%improvement in inference speed compared to the baseline,with only marginal reductions of 1.6%and 4.2%in mean average precision(mAP)at the intersection over union(IoU)thresholds of 0.5 and 0.5:0.95,*** work represents a significant advancement in scene text detection,striking a balance between speed and accuracy,making it well-suited for performance-constrained environments.

关键词： Scene text detection YOLOv5 lightweight object detection

Achieving high-efficient photocatalytic persulfate-activated degradation of tetracycline via carbon dots modified MIL-101(Fe)octahedrons

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Chinese Journal of Chemical Engineering 2024年第2期66卷 298-309页

作者： Hao Yuan Xinhai Sun Shuai Zhang Weilong Shi Feng Guo school of Material science and Engineering Jiangsu University of Science and TechnologyZhenjiang 212003China school of Energy and Power Jiangsu University of Science and TechnologyZhenjiang 212003China

The synergistic reaction of photocatalysis and advanced oxidation is a valid strategy for the degradation of harmful antibiotic ***,carbon dots(CDs)modified MIL-101(Fe)octahedrons to form CDs/MIL-101(Fe)composite photocatalyst was synthesized for visible light-driven photocatalytic/persulfate(PS)-activated tetracycline(TC)*** electron spin resonance(ESR)spectra,scavenging experiment and electrochemical analysis were carried out to reveal that the high visible light-driven photocatalytic degradation activity of TC over CDs/MIL-101(Fe)photocatalysts is not only ascribed to the production of free active radicals in the CDs/MIL-101(Fe)/PS system(·OH,·SO_(4-),^(1)O_(2),h^(+)and·O_(2)^(-))but also attributed to the consumption of electrons caused by the PS,which can suppress the recombination of photo-generated carriers as well as strong light scattering and electron trapping effects of ***,the possible degradation pathways were proposed by analyzing intermediates via liquid chromatography-mass spectrometry *** research presents a rational design conception to construct a CDs/PS-based photocatalysis/advanced oxidation technology with high-efficient degradation activity for the remediation of organic antibiotic pollutant wastewater and for the improvement of carrier transport kinetics of photocatalysts.

关键词： Carbon dots MIL-101(Fe) Photocatalytic Persulfate activation Tetracycline degradation

Grain refinement of 5A06 aluminum alloy welds caused by tungsten inert gas welding arc characteristics under Ar-He alternating gas supply conditions:a coupled method of water-cooled copper plate test/numerical simulation

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Journal of Iron and Steel Research International 2024年第3期31卷 767-777页

作者： Hong-bin Dai Jian Miao Jia-xin Lin school of Materials science and Engineering Harbin University of Science and TechnologyHarbin 150040HeilongjiangChina

The welding arc,as a carrier for the conversion of electrical energy to thermal energy,has a direct impact on the quality of welding by its properties and *** the tungsten inert gas(TIG)welding process under the condition of Ar-He alternating gas supply,the arc is alternately converted between Ar arc and He arc with an alternating gas supply cycle,which has obvious arc change *** FLUENT software was used to numerically simulate the characteristics of the TIG arc under the condition of alternating gas supply,and the arc temperature field,arc pressure,electric potential and current density distribution under the condition of alternating gas supply were *** with the real-time data of arc pressure measured by the water-cooled copper plate with holes,it is proved that the TIG arc has obvious dynamic characteristics under the condition of Ar-He alternating gas *** unique dynamic TIG arc acts on the 5A06 aluminum alloy weld,causing the molten pool to stir,resulting in uniform microstructure and grain refinement at the weld,and thereby improving the mechanical properties of the welded joint.

关键词： Alternating gas supply Grain refinement Numerical simulation Tungsten argon arc morphology Microstructure Mechanical property

SDCC: software-defined collective communication for distributed training

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science China(Information sciences) 2024年第9期67卷 105-125页

作者： Xin JIN Zhen ZHANG Yunshan JIA Yun MA Xuanzhe LIU school of Computer science Peking University Department of Computer science and technology Johns Hopkins University

Communication is crucial to the performance of distributed training. Today's solutions tightly couple the control and data planes and lack flexibility, generality, and performance. In this study, we present SDCC, a software-defined collective communication framework for distributed training. SDCC is based on the principle of modern systems design to effectively decouple the control plane from the data *** abstracts the operations for collective communication in distributed training with dataflow operations and unifies computing and communication with a single dataflow graph. The abstraction, together with the unification, is powerful: it enables users to easily express new and existing collective communication algorithms and optimizations, simplifies the integration with different computing engines(e.g., Py Torch and Tensor Flow) and network transports(e.g., Linux TCP and kernel bypass), and allows the system to improve performance by exploiting parallelism exposed by the dataflow graph. We further demonstrate the benefits of SDCC in four use cases.

关键词： machine learning systems distributed training deep learning collective communication software-defined networking