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Mechanistic insight into the synergy between nickel single atoms and nanoparticles on N-doped carbon for electroreduction of CO2

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Journal of Energy Chemistry 2025年第1期100卷 327-336页

作者： Mingdong Sun Wenwen Guan Cailing Chen Chao Wu Xiaoling Liu Biao Meng Tao Chen Yu Han Jun Wang Shibo Xi Yu Zhou State Key Laboratory of Materials-Oriented Chemical engineering College of Chemical Engineering Nanjing Tech University advanced Membranes and Porous Materials Center Physical Sciences and Engineering Division King Abdullah University of Science and Technology Institute of Sustainability for Chemicals Energy and Environment A*STAR (Agency for Science Technology and Research) College of Materials Science and engineering Sichuan University

The synergy of single atoms （SAs） and nanoparticles （NPs） has demonstrated great potential in promoting the electrocatalytic carbon dioxide reduction reaction （CO2RR）;however,the rationalization of the SAs/NPs proportion remains one challenge for the catalyst ***,a Ni2+-loaded porous poly（ionic liquids）(PIL) precursor synthesized through the free radical self-polymerization of the ionic liquid monomer,1-allyl-3-vinylimidazolium chloride,was pyrolyzed to prepare the Ni,N co-doped carbon materials,in which the proportion of Ni SAs and NPs could be facilely modulated by controlling the annealing *** catalyst Ni-NC-1000 with a moderate proportion of Ni SAs and NPs exhibited high efficiency in the electrocatalytic conversion of CO2into *** Ni K-edge X-ray absorption near-edge structure （XANES） spectra and theoretical calculations were conducted to gain insight into the synergy of Ni SAs and *** charge transfer from Ni NPs to the surrounding carbon layer and then to the Ni SAs resulted in the electron-enriched Ni SAs active *** the electroreduction of CO2,the coexistence of Ni SAs and NPs strengthened the CO2activation and the affinity towards the key intermediate of*COOH,lowering the free energy for the potential-determining*CO2→*COOH step,and therefore promoted the catalysis efficiency.

关键词： Single atom catalyst Synergy effect Carbon catalyst Electrocatalysis

Targets capture by distributed active swarms via bio-inspired reinforcement learning

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Science China(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 210-221页

作者： Kun Xu Yue Li Jun Sun Shuyuan Du Xinpeng Di Yuguang Yang Bo Li Institute of Biomechanics and Medical engineering Applied Mechanics Laboratory Department of Engineering MechanicsTsinghua University Institute of nuclear and New Energy Technology Tsinghua University Shanghai Aerospace Control Technology Institute Shanghai Key Laboratory of Aerospace Intelligent Control Technology College of Automation engineering Nanjing University of Aeronautics and Astronautics

Natural swarms arranged from cells to herds are usually decentralized but display intriguing collective intelligence in coordinating individuals across large scales to efficiently achieve their common goals. Learning from nature may provide new strategies for controlling collective dynamics of synthetic swarms to accomplish specific functions. Here, we present a bioinspired computational framework that steers distributed active swarms to collectively capture and merge targets via reinforcement learning. We exploit collective milling structures of natural herds to cage the targets, and adopt a switching control policy inspired by sperms' chiral dynamics to optimize the trajectories of individuals, through which the active swarms can selforganize to enclose single or multiple distant targets in a dynamical, adaptive and scalable manner. There exists a critical swarm size, beyond which the excessive competition between agents would generate large mechanical forces, leading to capture instability but enabling the transition from short-distance to long-distance merging capture of multiple targets. This work provides physical insights into distributed active swarms and could offer a multilevel, decentralized strategy toward controlling swarm robotics in wide applications such as bio-medical devices, machine immunity, and target clearance.

关键词： swarm intelligence robotics multi-tasks artificial intelligence bionics

Development of a radiographic method for measuring the discrete spectrum of the electron beam from a plasma focus device

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Plasma Science and Technology 2017年第7期19卷 26-33页

作者： Neda SHAMSIAN Babak SHIRANI BIDABADI Hosein PIRJAMADI Department of nuclear engineering Faculty of Advanced Sciences and Technologies University of Isfahan

An indirect method is proposed for measuring the relative energy spectrum of the pulsed electron beam of a plasma focus device. The Bremsstrahlung x-ray, generated by the collision of electrons against the anode surface, was measured behind lead filters with various thicknesses using a radiographic film system. A matrix equation was considered in order to explain the relation between the x-ray dose and the spectral amplitudes of the electron beam. The electron spectrum of the device was measured at 0.6 mbar argon and 22 kV charging voltage, in four discrete energy intervals extending up to 500 keV. The results of the experiments show that most of the electrons are emitted in the 125-375 keV energy range and the spectral amplitude becomes negligible beyond 375 keV.

关键词： magnetized plasma plasma focus plasma diagnostics electron beam energyspectrum x-ray dosimetry

Robust nonlinear control for nuclear reactors using sliding mode observer to estimate the xenon concentration

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nuclear Science and Techniques 2016年第2期27卷 106-114页

作者： G.R.Ansarifar H.R.Akhavan Department of nuclear engineering Faculty of Advanced Sciences and Technologies University of Isfahan

This paper presents findings on the sliding mode controller for a nuclear reactor. One of the important operations in nuclear power plants is load following. In this paper, a sliding mode control system, which is a robust nonlinear controller, is designed to control the pressurizedwater reactor power. The reactor core is simulated based on the point kinetics equations and six delayed neutron groups. Considering neutron absorber poisons and regarding the limitations of the xenon concentration measurement, a sliding mode observer is designed to estimate its value, and finally, a sliding mode control based on the sliding mode observer is presented to control the core power of reactor. The stability analysis is given by means Lyapunov approach; thus, the control system is guaranteed to be stable within a large range. The employed method is easy to implement in practical applications, and moreover,the sliding mode control exhibits the desired dynamic properties during the entire output-tracking process independent of perturbations. Simulation results are presented to demonstrate the effectiveness of the proposed observerbased controller in terms of performance, robustness and stability.

关键词：鲁棒非线性控制滑模观测器核反应堆估计氙气气浓度非线性鲁棒控制器滑模控制系统

Surface morphology and crystal orientation of electrodeposited tungsten coatings with different pulse parameters

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Rare Metals 2018年第5期37卷 407-412页

作者： Xian-Qin Fang Ying Zhang Kai-Gui Zhu Wen-Jia Han Jian-Gang Yu Zhe Chen Hui-Jun Shi Beijing Key Laboratory of advanced nuclear Energy Materials and Physics School of Physics and Nuclear Energy EngineeringBeihang University

This study was conducted to investigate the influence of pulse parameters on the surface morphology and crystal orientation of the tungsten coatings electrodeposited on pure copper substrates. The deposited coatings were analyzed by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and energy-dispersive spectrometer （EDS）. SEM analysis indicates that pulse parameters have significant influences on the surface morphology of the deposited coatings. Meanwhile, the change in grain size of the tungsten coatings demonstrates that the change in frequency and duty cycle could cause the variation of nucleation rate and grain growth of deposits. Moreover, no obvious diffusion layer at the coating/substrate interface is found by line analysis of EDS. XRD results reveal that tungsten coatings are of bcc structure and the preferred orientation of the deposits varies with duty cycle and period.

关键词： Tungsten coating Electrodeposition Pulse parameters Crystal orientation Surface morphology

Mechanical wet-milling and subsequent consolidation of ultra-fine Al_2O_3-(ZrO_2+3%Y_2O_3) bioceramics by using high-frequency induction heat sintering

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中国有色金属学会会刊：英文版 2007年第1期17卷 21-26页

作者： Khalil Abdelrazek KHALIL Sug Won KIM division of advanced Materials engineering RIAMD Chonbuk National University

Alumina/zirconia composites were synthesized by wet-milling technique and rapid consolidation with high frequency induction heat sintering(HFIHS). The starting materials were a mixture of alumina micro-powder (80%, volume fraction) and 3YSZ nano-powders (20%). The mixtures were optimized for good sintering behaviors and mechanical properties. Nano-crystalline grains are obtained after 24 h milling. The nano-structured powder compacts are then processed to full density at different temperatures by HFIHS. Effects of temperature on the mechanical and microstructure properties were studied. Al2O3-3YSZ composites with higher mechanical properties and small grain size are successfully developed at relatively low temperatures through this technique.

关键词：生物陶瓷烧结工艺高频诱导微观结构机械性能

Enhancement of filtration efficiency by electrical charges on nebulized particles

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Particuology 2018年第2期16卷 81-90页

作者： Hui Chen Zhenyi Zhang Zhenzhong Zhang Feng Jiang Ruiming Du Environmental Technology division Institute of Nuclear and New Energy Technology Tsinghua University Beijing 100084 China Institute of nuclear and New Energy Technology Collaborative Innovation Center of Advanced Nuclear Energy Technology Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education Ysinghua University Beijing 100084 China

There have been few investigations of effects of electrical charge, carried by lab-generated particles, on filtration efficiency testing. Here, we measured the elementary charge on particles and the fraction of particles carrying that charge with a combined electrometer, differential mobility analyzer, and scanning mobility particle sizer. A typical solid NaCI aerosol and liquid diethylhexyl sebacate （DEHS） aerosol were generated with Collison and Laskin nebulizers, respectively. Our experimental results showed that NaCI aerosols carried more charge after aerosol generation. The average net elementary charge per particle was approximately 0.07. The NaCI aerosol was overall positively charged but contained a mixture of neutral and charged particles. Individual particles could carry at most four elementary charges. According to constant theorem, we speculated that original NaC1 aerosol contained 17% neutral, 45% positive-, and 38% negative-charged particles in the diameter range from 30 to 300nm. A Kr-85 neutralizer was used to decrease the charge on the NaCI particles. Our results indicated that the DEHS aerosol was electrically neutral. The effects of electric charge on particle collection by electret and electroneutral high efficiency particulate air （HEPA） filters were analyzed. Theoretical calculations suggested that charges on original NaCI aerosol particles enhanced the filtration efficiency of HEPA filters,

关键词： Nebulization Artificial aerosol Electrical charges Charge distribution Electret HEPA filter Penetration

New friction factor and Nusselt number equations for laminar forced convection of liquid with variable properties

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Science China(Technological Sciences) 2018年第1期61卷 98-109页

作者： ZHAO HouJian LI XiaoWei WU XinXin Key Laboratory of advanced Reactor engineering and Safety of Ministry of Education Collaborative Innovation Center of Advanced Nuclear Energy Technology Institute of Nuclear and New Energy Technology Tsinghua University

Friction factor and heat transfer coefficient of liquid flow with variable properties can significantly differ from that with constant properties. Existing equations obtained by regression analysis of experimental data use correction factors to account for variable property effect. They are limited to specific kind of fluid and low or medium temperature differences. The correction factors of the equations for heating and cooling conditions are different. New explicit friction factor and Nusselt number equations for laminar forced convection of liquid with variable properties are derived with a first order approximation of dynamic viscosity-temperature variation. The new equations are applicable to all kinds of liquids and can be used for large temperature differences. Governing equations of laminar forced convection of water and ethanol are numerically solved using computational fluid dynamics(CFD)method and the results are used to verify the derived equations. The derived equations show good predictions of friction factors and Nusselt numbers for both heating and cooling conditions and show more accurate predictions than the existing equations. A dimensionless number is also introduced based on theoretical analysis to evaluate property variation effects on friction factors and heat transfer coefficients.

关键词： laminar convection friction factor heat transfer coefficient variable property

First-principle studies of radioactive fission productions Cs/Sr/Ag/I adsorption on chrome-molybdenum steel in Chinese 200 MW HTR-PM

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nuclear Science and Techniques 2017年第6期28卷 123-132页

作者： Chuan Li Chao Fang Chen Yang Institute of nuclear and New Energy Technology Collaborative Innovation Center of Advanced Nuclear Energy TechnologyKey Laboratory of Advanced Reactor Engineering and Safety of Ministry of EducationTsinghua University

Chrome-molybdenum steel(2·1/4Cr1Mo) is one of the main products of steam *** adsorption behaviors of radioactive fission products on2·1/4Cr1Mo surface are critical in the analysis of ***,the adsorption behavior of cesium,strontium,silver and iodine on 2·1/4Cr1Mo was investigated with first-principle calculations that the Ag and I atoms prefer to be adsorbed at the square hollow site of the face-centered cubic iron cell with a binding energy of about 1 and 3 eV,*** contrast,Cs and Sr atoms are not adsorbed on the surface of the 2·1/*** results are again confirmed via analysis of charge density differences and the densities of ***,the adsorption rates of these fission products show that only I and Ag have significant adsorption on the metal *** adsorption results explain the amount of adsorbed radionuclides for an evaluation of nuclear safety in *** micro-pictures of the interaction between fission products and materials are a new and useful way to analyze the source term.

关键词： First-principle calculation Fission product Adsorption behavior HTR-PM