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Microstructure,hardening and deuterium retention in CVD tungsten irradiated with neutrons at temperatures of defect recovery stagesⅡandⅢ

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Tungsten 2022年第3期4卷 248-260页

作者： Xiao-Ou Yi Tatsuya Kuwabara Vladimir KhAlimov Yu-Feng Du wen-tuo han Ping-Ping Liu Bin-You Yan Jiu-Peng Song Kenta Yoshida Takeshi Toyama Fa-Rong Wan Somei Ohnuki Yuji Hatano Yasuyoshi Nagai School of Materials Science and Engineering University of Science and Technology BeijingBeijing100083China Graduate School of Engineering Nagoya UniversityFuro-choChikusa-kuNagoya464-8063Japan Frumkin Institute of Physical Chemistry and Electrochemistry Russian Academy of SciencesMoscow119071Russia Institute for Materials Research Tohoku UniversityNarita-cho 2145-2OaraiIbaraki311-1313Japan Xiamen Tungsten Co.Ltd. Xiamen361021China School of Materials Science and Engineering Xihua UniversityChengdu610039China Hydrogen Isotope Research Center University of ToyamaToyama930-8555Japan

Samples of ultra-high-purity tungsten prepared using chemical vapour deposition(CVD)technique were irradiated with neutrons at temperatures T_(irr)=373-483 K(stage Ⅱ of defect recovery)and T_(irr)=573-673 K(stage Ⅲ)up to 0.15 displacements per atom(dpa)in the Belgian reactor(BR2).The study of the microstructure of neutron-damaged samples using transmission electron microscopy(TEM)revealed visible defects with a predominance of dislocation loops.With an increase in the neutron irradiation temperature,the spatial distribution of the loops acquired pronounced inhomogeneity,and their average size moderately increased.Cavities and voids were not observed.Irradiation-induced hardening was found and a linear correlation was obtained between Vickers microhardness and nanohardness for undamaged and neutron-irradiated CVD-W samples.Irradiation of tungsten with neutrons led to a significant increase in the retention of deuterium,which accumulated mainly in vacancy-type traps.Furthermore,the influence of the columnar grain structure in low-dose neutron-irradiated tungsten seemed to be non-trivial upon deuterium retention.

关键词： CVD-W Neutron irradiation Microstructure Hardening Deuterium retention

General formalism for dirty extreme-mass-ratio inspirals

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Science China(Physics,Mechanics & Astronomy) 2024年第7期67卷 22-29页

作者： Ye Jiang wen-Biao han Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhou 310024China Shanghai Frontiers Science Center for Gravitational Wave Detection Shanghai 200240China

Detecting the environment around the supermassive black holes and tests of general relativity are important applications of extreme-mass-ratio inspirals(EMRIs).There is still a challenge to efficiently describe various“dirty”impacts on the inspirals,such as dark matter,gas,dipole radiation,and electromagnetic interaction.In this study,we find the inherent linearity of the asymptotic solution of the inhomogeneous Teukolsky equation.On the basis of this property,we completely decouple the factors of the perturber and the background spacetime in the energy fluxes and waveforms.With the new decoupling form,the waveforms of EMRIs with non-geodesic motion in Kerr spacetime can be conveniently calculated.This will help to resolve the environment(including gas,field,dark matter,electromagnetic interaction)around supermassive black holes and test general relativity.

关键词： gravitational wave Teukolsky equation extreme-mass-ratio inspirals

Galerkin-based quasi-smooth manifold element(QSME)method for anisotropic heat conduction problems in composites with complex geometry

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Applied Mathematics and Mechanics(English Edition) 2024年第1期45卷 137-154页

作者： Pan WANG Xiangcheng han Weibin wen Baolin WANG Jun LIANG School of Civil Engineering Central South UniversityChangsha 410083China Institute of Advanced Structure Technology Beijing Institute of TechnologyBeijing 100081China School of Science Harbin Institute of TechnologyShenzhen 518055Guangdong ProvinceChina

The accurate and efficient analysis of anisotropic heat conduction problems in complex composites is crucial for structural design and performance evaluation. Traditional numerical methods, such as the finite element method(FEM), often face a trade-off between calculation accuracy and efficiency. In this paper, we propose a quasi-smooth manifold element(QSME) method to address this challenge, and provide the accurate and efficient analysis of two-dimensional(2D) anisotropic heat conduction problems in composites with complex geometry. The QSME approach achieves high calculation precision by a high-order local approximation that ensures the first-order derivative continuity.The results demonstrate that the QSME method is robust and stable, offering both high accuracy and efficiency in the heat conduction analysis. With the same degrees of freedom(DOFs), the QSME method can achieve at least an order of magnitude higher calculation accuracy than the traditional FEM. Additionally, under the same level of calculation error, the QSME method requires 10 times fewer DOFs than the traditional FEM. The versatility of the proposed QSME method extends beyond anisotropic heat conduction problems in complex composites. The proposed QSME method can also be applied to other problems, including fluid flows, mechanical analyses, and other multi-field coupled problems, providing accurate and efficient numerical simulations.

关键词： anisotropic heat conduction quasi-smooth manifold element(QSME) composite with complex geometry numerical simulation finite element method(FEM)

Interplay between geometric and electronic structures of Pt entities over TiO_(2) for CO oxidation

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Science China Chemistry 2024年第2期67卷 705-714页

作者： Xixiong Zhang wen Shi Shaobo han Yong Li wenjie Shen School of Chemistry Dalian University of TechnologyDalian116024China State Key Laboratory of Catalysis Dalian Institution of Chemical PhysicsChinese Academy of SciencesDalian116023China

Monodispersed Pt colloids with a mean size of 2 nm were deposited uniformly on the {110} facets of a rod-shaped rutile TiO_(2),forming a well-defined Pt/TiO_(2) system.Oxidative treatment of this precursor at elevated temperatures re-dispersed the Pt particles into clusters and single-atoms.Air-calcination at 673 K partially oxidized the Pt particle surface,while calcination at 773 K yielded Pt Oxclusters of 1.6 nm in 7–8 atomic layers.Further calcination at 873 K formed a mixture of raft-like PtO_(x) clusters(1.6 nm,1–2 atomic layers) and cationic single-atoms.When tested for CO oxidation at 373 K,the Pt particles showed a higher activity than the Pt Oxclusters,whereas the cationic single-atoms were much less active.Subsequent H_(2)-reduction at 473 K converted the partially oxidized Pt particles into the metallic species,but they were encapsulated by TiO_(2)–xoverlayers because of the strong metal–support interactions,which decreased the activity dramatically.H_(2)-reduction of the PtO_(x) clusters at473 K enhanced the fraction of metallic Pt species without changing the size and geometry,and promoted the activity substantially.H_(2)-treatment of Pt single-atoms at 473 K increased the activity only moderately because most Pt species still kept at cationic species.These results straightforwardly differentiated the catalytic behavior of Pt particles,clusters and single-atoms at the same metal loading and over the same TiO_(2) support,and further demonstrated that the electronic structures of Pt entities played a decisive role in the catalytic oxidation,in addition to the specified sizes.

关键词： Pt/TiO_(2)catalyst size effect Pt clusters active sites electronic structures CO oxidation

Carbon efficiency modeling and optimization of solar-powered cellular networks

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Science China(Information Sciences) 2024年第5期67卷 228-243页

作者： Yuxi ZHAO Xiaohu GE wen YAN Tao han Yi ZHONG School of Electronic Information and Communications Huazhong University of Science and Technology Huawei Technology Co. Ltd.

As wireless communication traffic experiences rapid growth, the carbon emissions caused by the communication industry are also on the rise. To achieve “carbon neutrality”, researchers are considering the use of renewable energy sources to power cellular networks, thereby reducing carbon emissions. However, a challenge arises when using renewable energy, specifically owing to the unpredictable nature of both the energy consumption of the cellular network and the power generation from renewable sources. This inconsistency results in low renewable energy utilization and reduced carbon efficiency. Herein, we construct a carbon efficiency model of solar-powered cellular networks using practical data from solar radiation. We propose a mechanism that alternately optimizes the performance of the renewable energy network and the cellular network. This approach is based on convex optimization theory and the Dinkelback algorithm, and it leads to the design of a carbon efficiency optimization algorithm. This algorithm aims to improve the carbon efficiency of cellular networks and reduce their carbon emissions. Simulation results demonstrate that our optimization scheme yields a maximum improvement of 2.56 × 108bps/g in the carbon efficiency of the cellular network as compared to conventional power allocation schemes such as the traditional water filling method and heuristic energy sharing and charge/discharge algorithms.

关键词： cellular networks renewable energy carbon efficiency convex optimization theory dinkelbach

Dynamic simulation analysis of molten salt reactor-coupled air-steam combined cycle power generation system

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Nuclear Science and Techniques 2024年第2期35卷 222-233页

作者： Jing-Lei Huang Guo-Bin Jia Li-Feng han wen-Qian Liu Li Huang Zheng-han Yang Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China University of Chinese Academy of Sciences Beijing 100049China

A nonlinear dynamic simulation model based on coordinated control of speed and flow rate for the molten salt reactor and combined cycle systems is proposed here to ensure the coordination and stability between the molten salt reactor and power system.This model considers the impact of thermal properties of fluid variation on accuracy and has been validated with Simulink.This study reveals the capability of the control system to compensate for anomalous situations and maintain shaft stability in the event of perturbations occurring in high-temperature molten salt tank outlet parameters.Meanwhile,the control system’s impact on the system’s dynamic characteristics under molten salt disturbance is also analyzed.The results reveal that after the disturbance occurs,the controlled system benefits from the action of the control,and the overshoot and disturbance amplitude are positively correlated,while the system power and frequency eventually return to the initial values.This simulation model provides a basis for utilizing molten salt reactors for power generation and maintaining grid stability.

关键词： Molten salt reactor Combined cycle Dynamic characteristic Control

Plane-controlled growth strategy improves electrochemical performance of cobalt-free LiNi0.9Mn0.1O2 cathode

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Progress in Natural Science:Materials International 2024年第3期34卷 569-577页

作者： Hao Tong Xun Yuan Ningbo Qin Yaocong han Yan Cheng Fangli Ji Ruirui tuo Changlang Liang Yi Wang Qilin Tong Zhaozhe Yu Guangxi Key Laboratory of Manufacturing Systems and Advanced Manufacturing Technology Guilin University of Electronic Technology Guangxi CNGR New Energy Science & Technology Co. LTD. Guangxi Institute of Science and Technology Development Co. LTD. School of Chemistry and Chemical Engineering Guangxi Minzu University

The ultra-high nickel-layered cathodes（Ni ≥ 90 %） has garnered significant attention due to its high specific capacity. However, the widespread application of ultra-high nickel-layered cathodes still suffers limitation by structural instability and poor rate performance. Herein, a crystal-face-induced strategy is proposed to enhance rate and cycling performances of the electrode by constructing rapid Li+diffusion channel and reducing internal grain boundaries of secondary particles. The crystal-face-induced strategy facilitates the growth of {010} lattice plane. Highly exposed {010} planes provide wide-open and unobstructed channels for Li+deintercalation/intercalation, enhances the electrode diffusion kinetics, and thus improves the electrode rate performance. In addition, this strategy promotes the primary particle growth, reduces the grain boundaries of secondary particles and mitigates the electrode/electrolyte interface side reactions, enhancing the structural stability and cycling life of the electrode. Accordingly, the modified sample achieved a reversible specific capacity of 198.3 mAh g-1at 1 C(1 C = 180 mA g-1) and maintained a capacity retention rate of 88.5 % after 100 cycles, higher than that of the original sample(73.6 %, 146 mAh g-1). At the high rate of 5 C, it can maintain a high specific capacity of 178mAh g-1（capacity retention rate of 99 %） after 150 cycles. This work is a leap in ultra-high nickel-layered cathodes development and provides insights into the design of electrode materials for other batteries.

关键词： Cobalt-free nickel-rich cathode Lithium-ion battery Plane-controlled growth strategy Rate and cycling performances

Advances in depressants for flotation separation of Cu–Fe sulfide minerals at low alkalinity:A critical review

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International Journal of Minerals,Metallurgy and Materials 2024年第1期31卷 1-17页

作者： Qicheng Feng wenhang Yang Maohan Chang Shuming wen Dianwen Liu Guang han State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization Faculty of Land Resource EngineeringKunming University of Science and TechnologyKunming 650093China Yunnan Key Laboratory of Green Separation and Enrichment of Strategic Mineral Resources Kunming University of Science and TechnologyKunming 650093China

The flotation separation of Cu–Fe sulfide minerals at low alkalinity can be achieved using selective depressants.In the flotation system of Cu–Fe sulfide minerals,depressants usually preferentially interact with the pyrite surface to render the mineral surface hydrophilic and hinder the adsorption of the collector.This review summarizes the advances in depressants for the flotation separation of Cu–Fe sulfide minerals at low alkalinity.These advances include use of inorganic depressants (oxidants and sulfur–oxygen compounds),natural polysaccharides (starch,dextrin,konjac glucomannan,and galactomannan),modified polymers (carboxymethyl cellulose,polyacrylamide,lignosulfonate,and tricarboxylate sodium starch),organic acids (polyglutamic acid,sodium humate,tannic acid,pyrogallic acid,salicylic acid,and lactic acid),sodium dimethyl dithiocarbamate,and diethylenetriamine.The potential application of specific inorganic and organic depressants in the flotation separation of Cu–Fe sulfide minerals at low alkalinity is reviewed.The advances in the use of organic depressants with respect to the flotation separation of Cu–Fe sulfide minerals are comprehensively detailed.Additionally,the depression performances and mechanisms of different types of organic depressants on mineral surfaces are summarized.Finally,several perspectives on depressants vis-à-vis flotation separation of Cu–Fe sulfide minerals at low alkalinity are proposed.

关键词： Cu–Fe sulfide minerals flotation separation selective depressants depression mechanism

Reactive oxygen species:Multidimensional regulators of plant adaptation to abiotic stress and development

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Journal of Integrative Plant Biology 2024年第3期66卷 330-367页

作者： Pengtao Wang wen-Cheng Liu Chao han Situ Wang Ming-Yi Bai Chun-Peng Song State Key Laboratory of Crop Stress Adaptation and Improvement School of Life SciencesHenan UniversityKaifeng 475004China The Key Laboratory of Plant Development and Environmental Adaptation Biology Ministry of EducationSchool of Life SciencesShandong UniversityQingdao 266237China Faculty of Science McGill UniversityMontreal H3B1X8Canada

Reactive oxygen species(ROS)are produced as undesirable by-products of metabolism in various cellular compartments,especially in response to unfavorable environmental conditions,throughout the life cycle of plants.Stressinduced ROS production disrupts normal cellular function and leads to oxidative damage.To cope with excessive ROS,plants are equipped with a sophisticated antioxidative defense system consisting of enzymatic and non-enzymatic components that scavenge ROS or inhibit their harmful effects on biomolecules.Nonetheless,when maintained at relatively low levels,ROS act as signaling molecules that regulate plant growth,development,and adaptation to adverse conditions.Here,we provide an overview of current approaches for detecting ROS.We also discuss recent advances in understanding ROS signaling,ROS metabolism,and the roles of ROS in plant growth and responses to various abiotic stresses.

关键词： abiotic stress growth and development plant reactive oxygen species