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Ultrafine polycrystalline titania nanofibers for superior sodium storage

Journal of Energy Chemistry 2019年第11期28卷 153-161页

作者： Zhidan Diao Daming Zhao Chunxiao Lv Hongli Liu Dongjiang Yang Shaohua Shen International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi’an Jiaotong UniversityXi’an 710049ShaanxiChina School of Environmental Science and Engineering Collaborative Innovation Centerfor Marine Biomass FibersMaterials and Textiles of Shandong ProvinceQingdao UniversityQingdao 266071ShandongChina

Sodium ion batteries have a huge potential for large-scale energy storage for the low cost and abundance of sodium resources. In this work, a novel structure of ultrafine polycrystalline TiO2 nanofibers is prepared on nickel foam/carbon cloth by a simple vapor deposition method. The as-prepared TiO2 nanofibers show excellent performance when used as anodes for sodium-ion batteries. Specifically, the TiO2 nanofibers@nickel foam electrode delivers a high reversible capacity of 263.2 m Ahg^-1 at 0.2 C and maintains a considerable capacity of 144.2 m Ahg^-1 at 10 C. The TiO2 nanofibers@carbon cloth electrode also shows excellent high-rate capability, sustaining a capacity of 148 m Ahg^-1 after 20 0 0 cycles at 10 C. It is believed that the novel nanofibrous structure increases the contact area with the electrolyte and greatly shortens the sodium ion diffusion distance, and meanwhile, the polycrystalline nature of nanofibers exposes more intercalation sites for sodium storage. Furthermore, the density functional theory calculations exhibit strong ionic interactions between the exposed TiO2(101) facets and sodium ions, leading to a preferable sodiation/desodiation process. The unique structural features endow the TiO2 nanofibers electrodes great advantages in rapid sodium storage with an outstanding high-rate capability.

关键词： Polycrystalline titania Nanofibers Sodium storage High-rate capability

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Experimental study on pressure and temperature distribution characteristics of subcritical and supercritical water in vertical flow channel

International Journal of Fluid Engineering

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International Journal of Fluid engineering 2024年第4期1卷 56-64页

作者： Hui Jin Huibo Wang Yi Li Petr A.Nikrityuk State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityShaanxi 710049China Mechanical Engineering Department Eindhoven University of TechnologyEindhovenNetherlands Chemical and Materials Engineering Department University of AlbertaEdmontonAlberta T6G 2R3Canada

To enhance knowledge about efficiency improvement and reactor optimization in supercritical water gasification,an experimental system was designed to study the pressure and temperature distribution of subcritical and supercritical water in a channel,representing a simplified continuous *** pressure drop and temperature distribution along and perpendicular to the forced flow are studied by the measure points inserted inside the test *** results show that the pressure drop in the test section is linearly negatively correlated with the average enthalpy of the inlet and outlet,eventually reaching negative values(-0.177 MPa)at high average enthalpy(2300 kJ kg^(-1)).Temperature and specific enthalpy along the flow direction match theoretical estimates,except near the pseudocritical *** subcritical cases,horizontal temperature differences are positively correlated with enthalpy differences and mass flow rates but remain nearly constant in supercritical ***,with fluid temperature rising from the pseudocritical point,the horizontal temperature difference first increases,then decreases,and reaching a peak of 4.29 K at a fluid temperature of 664 *** of the obtained data reveals that the negative correlation and values of the pressure drop are caused by fluid volume ***,fluid volume expansion,near-wall natural convection,and turbulent forced flow fluctuations contribute to horizontal temperature non-uniformity.

关键词： flow distribution channel

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Three-dimensional modeling and thermal hydraulic analysis of high temperature gas-cooled reactor core 27

Three-dimensional modeling and thermal hydraulic analysis of...

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27th International Conference on Nuclear engineering: Nuclear power Saves the World!, ICONE 2019

作者： Zhang, Shuangbao Li, Liangxing Xie, Wei Wang, Kailin State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xianning West Road 28# Xi'an city710049 China

ISBN: (纸本)9784888983051

The high temperature gas-cooled reactor (HTR) is an advanced reactor with the characteristics of Generation IV nuclear energy system which has attracted wide attention due to the excellent performances of inherent safety, economy, high efficiency and low carbon environmental protection. Accurate and reliable thermal hydraulic analysis is of great significance for studying the flow and heat transfer in the core of HTR. Based on the coolant flow and heat transfer process in the core of HTR, this study establishes a three-dimensional coupled model by using CFD (Computational Fluid Dynamics) software firstly, and the flow and heat transfer process of helium coolant is simulate in the core. The temperature variation in the reactor is calculated under the conditions of steady-state operation of the HTR core, and the calculation results by the present models were compared with calculated results from the benchmark software of Thermix and the related published results. The results showed that the average temperature of the outlet section is 759.6 ℃, and the maximum relative error with the published data is 1.25%. The steady-state results under the full power conditions based on the three-dimensional model are in good agreement with the calculation data from those of THERMIX. It stated that the three-dimensional model can be employed to simulate the thermal hydraulic analysis for HTR. On this basis, the heat transfer characteristics of core is simulated under 50% full power, and the are result helpful for the operation and design of HTR. © 2018-2019 by JSME

关键词： Porous materials

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Review on development of carbon nanotube field emission cathode for space propulsion systems

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High Voltage 2020年第4期5卷 409-415页

作者： Chao Huo Feng Liang An-bang Sun Science and Technology on Combustion Internal Flow and Thermal-structure LaboratorySchool of AstronauticsNorthwestern Polytechnical UniversityXi'anShaanxiPeople's Republic of China Faculty of Metallurgical and Energy Engineering Kunming University of Science and TechnologyKunmingPeople's Republic of China State Key Laboratory of Electrical Insulation and Power Equipment School of Electrical EngineeringXi'an Jiaotong UniversityXi'an 710049People's Republic of China

In recent years,small-size,low-weight aerospace propulsion systems have developed rapidly for space exploration,on-orbit scientific instruments and extra space missions,while additional electron emission devices are commonly required in those propulsion *** nanotube(CNT)based field emission cathodes exhibit extraordinary field emission properties and are regarded to be an ideal alternative of conventional thermionic or hollow *** this study,the authors give an overview of present status of researches on CNT-based electron emission cathodes for utilising as neutralisers or electron sources particularly in space electric propulsion systems,the theory and characteristics of CNT are also ***,challenges,problems and possible solutions before actual applications of CNT in a space mission are discussed accordingly.

关键词： field neutral emission

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Experimental Study on the Boiling Heat Transfer Characteristics of R134a in a Helically Coiled Tube

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Kung Cheng Je Wu Li Hsueh Pao/Journal of engineering Thermophysics 2019年第3期40卷 587-593页

作者： Niu, Xiao-Juan Yuan, Huai-Jie Quan, Chen Bai, Bo-Feng Zhao, Liang State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

The characteristics of R134a boiling heat transfer in a vertically helically coiled tube are studied. The experimental parameters are as follows: the heat flux is 10∼60 kW•m-2, the mass flux is 195∼400 kg•m-2 •s-1, the pressure is 0.8∼1.1 MPa, and the outlet vapor quality is 0.1∼0.9. The experimental data are compared with the existing correlations of boiling heat transfer coefficient. Based on the analysis of boiling heat transfer mechanism, a new correlation for boiling heat transfer in coiled tube is proposed. The circumferential distribution characteristics of wall temperature and heat transfer coefficient are analyzed. The wall temperatures at inner and top side are relatively higher, and the heat transfer coefficients at the bottom and the outer side are relatively higher. The local heat transfer coefficients are compared with the new correlation proposed in this paper. The results show that the heat transfer coefficients at top and bottom sides can be predicted by the new correlation. However, the new correlation underestimates the heat transfer coefficient at the outer side and overestimates that at the inner side, the deviations are 16.6% and -11.9% respectively. © 2019, Science Press. All right reserved.

关键词： Heat transfer coefficients

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Numerical analysis of the axial lead-bismuth pump performace base on the different rotation speed 18

Numerical analysis of the axial lead-bismuth pump performace...

引用

18th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH 2019

作者： Wang, Kailin Li, Liangxing Xie, Wei Zhang, Shuangbao State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xianning West Road 28# Xi’an city710049 China

The hydraulic performance of lead-bismuth eutectic (LBE) pump is of great importance for the safety aspects concerning lead-alloy cooled fast reactors (LFRs). To investigate the effect of different rotation speed on the performance of axial LBE pump, different rotation speed axial LBE pumps are designed by planar cascade and streamline method with the same mass flow rate and hydraulic head. Ansys BladeGen is used to establish the three-dimensional model of the axial-flow pump. CFD software (Ansys CFX) carry out numerical calculation. Numerical studies are used to compared the performance between two pumps with different rotation speed. To improve the accuracy of CFD simulation, the numerical result is verified by grid independence method and compared with theoretical calculation result. The flow velocity of the liquid LBE have great impact on the design of LBE pump because of the requirement to avoid affect of corrosion. It is found that the maximum flow velocity of low rotation speed pump is about 7.8 m/s, which is lower than the maximum flow velocity of high rotation speed pump in the case of constant volume and performance. Performance of low rotation speed pump meets the requirements of the reactor operating under long-term high load. The research results could be a viable solution used as a reference for the development of LFRs. © 2019 American Nuclear Society. All rights reserved.

关键词： Pumps

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Effect of ammonium ion on the corrosion behavior of Ni 2 FeCrMo 0.2 high-entropy alloy in simulated haze solution

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Journal of Materials Research and Technology 2025年

作者： Kai Wang Qilong Zhao Yanhui Li Ruidong Li Qipeng Xu State Key Laboratory of Eco-hydraulics in Northwest Arid Region Xi’an University of Technology No.5 Jinhua South Road Xi’an 710048 China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University No.28 Xianning West Road Xi’an 710049 China School of Chemical Engineering Northwest University No.229 Taibai North Road Xi’an 710069 China

Various constituents of PM 2.5 in haze can accelerate metal corrosion, but traditional carbon steel and stainless steel perform poorly in such complex corrosive environments, and thus developing new corrosion-resistant materials are of great importance for mitigating haze-induced corrosion. The corrosion behavior of Ni 2 FeCrMo 0.2 alloy in haze-simulating aqueous solutions containing various constituents of PM 2.5 in haze is investigated. By the coupling analysis of electrochemical experiments, corrosion morphology, and corrosion product film, the influence of NH+ 4 concentration on the corrosion mechanism related to multi-principal metal elements is revealed. The results show that the Ni 2 FeCrMo 0.2 alloy exhibits superior corrosion resistance compared with 2205 duplex stainless steel. As the NH+ 4 concentration increases, the corrosion rate increases initially but then decreases at higher NH+ 4 concentrations, and the corrosion morphology also confirms this changing trend. The corrosion prompt is primarily due to the lower solution pH caused by the hydrolysis reaction of NH+ 4. In contrast, the corrosion inhibition at higher NH+ 4concentration is attributed to the passive film on the alloy surface, which is composed of Cr, Fe, Mo, Ni, and their oxides, with the presence of Mo elements forming a unique structure that improved the density and stability of the film, thereby inhibiting the growth of corrosion pits. The changing trend of corrosion film resistance and corrosion product film thickness agrees well with this change in corrosion rate. This study provides an insightful understanding of the corrosion behavior of multi-principal alloy materials in haze environments, which is crucial for the corrosion protection design of metal equipment materials.

关键词： Haze constituents Corrosion High entropy alloy Passive film

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Laser-Synthesized Ligand-Free Cu Nanocatalysts in Electrochemical CO2 Reduction to Methane

arXiv

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arXiv 2025年

作者： Ye, Taiping Lactionov, Artyom Sozaev, Islam Popov, Anton Klimentov, Sergei Kabashin, Andrei V. Liu, Ya International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Shaanxi 710049 China National Research Nuclear University MEPhI Moscow115409 Russia CNRS LP3 Aix-Marseille Université Marseille13288 France

Electrochemical CO2 reduction (eCO2R) represents a pivotal strategy for mitigating global carbon emissions while simultaneously converting renewable energy into storable chemical fuels. Copper-based catalysts have been extensively explored in this field due to their unique capability to catalyze multi-carbon products. However, the intrinsic complexity of eCO2R pathways on Cu surfaces often leads to mixed product distributions, posing a significant challenge for achieving high selectivity toward a single desired hydrocarbon. Herein, we report a breakthrough in methane selectivity using laser-synthesized, ligand-free Cu nanomaterials. Unlike conventional Cu catalysts that produce diverse products, these ligand-free nanoparticles exhibit unprecedented selectivity for methane (CH4) with a Faradaic efficiency (FE) exceeding 70% at superior overpotentials. The absence of surface ligands, a direct consequence of the ultrafast laser ablation synthesis, ensures abundant exposed active sites with tailored electronic and geometric configurations. We attribute the exceptional methane selectivity to the synergistic effects of active sites-rich surfaces and optimized *CO intermediate binding energetics, which favor the protonation pathway toward CH4 rather than C–C coupling. This work not only resolves the longstanding selectivity dilemma in Cu-catalyzed eCO2R but also establishes laser-synthesized ligand-free nanomaterials as a versatile platform for designing high-performance electrocatalysts. Copyright © 2025, The Authors. All rights reserved.

关键词： Nanoparticles

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Lithium Extraction from High Magnesium Salt Lake Brine with an Integrated Membrane Technology

SSRN

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SSRN 2022年

作者： Ashraf, Muhammad Awais Usman, Muhammad Hussain, Iftikhar Ahmad, Faraz Guo, Shiwei Zhang, Lu State Key Laboratory of Multiphase Complex Systems CAS Key Laboratory of Green Process and Engineering Institute of Process Engineering Chinese Academy of Sciences Beijing100190 PR China University of Chinese Academy of Sciences Beijing100049 China Washington State University United States Department of Mechanical Engineering City University of Hong Kong 83 Tat Chee Avenue Kowloon Hong Kong Key Laboratory of Coal Science and Technology Taiyuan University of Technology Taiyuan030024 China North China Electric Power University Hebei Key Lab of Power Plant Flue Gas Multi-Pollutants Control Department of Environmental Science and Engineering Baoding071000 China Faculty of Economics and Business

Lithium extraction is a great challenge from the high magnesium content salt solution. In this work, an integrated polyamide tight ultrafiltration (UF) and nanofiltration (NF) membranes are systematically investigated to separate Li+ from a high magnesium salt solution. Tight ultrafiltration UA001 and nanofiltration NF270 membranes in the integrated-cascade system not only increased Li+ permeation to 82.5% but also enhanced the high Mg2+ retention to 94.6% from the ternary salt solution of LiCl and MgCl2. The transport model was also developed to calculate the real retention of Li+ and Mg2+, under constant pressure mode. The separation efficiency SFLi/Mg for the ternary salt solution of LiCl+MgCl2+H2O was more than 15 at a constant pressure of 25 bars with an integrated membrane process, which was higher as compared to single-stage UF and NF270 membranes. Moreover, the high Mg2+/Li+ ratio was also reduced from 30 to 1.9 in the integrated-cascade membrane process. © 2022, The Authors. All rights reserved.

关键词： Magnesium compounds

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Wake of a stationary sphere near a wall

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Huagong Xuebao/CIESC Journal 2019年第9期70卷 3300-3306页

作者： Li, Xing Bai, Bofeng State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'anShaanxi710049 China

The flow characteristics of the sphere under uniform flow in a large space have been extensively studied, but the influence of the wall on the flow characteristics of the sphere is not clear. The wake of the particle is focused. Results show that there are three regimes of the sphere wake, which are steady wake, unsteady symmetric wake and unsteady asymmetric wake. If Re400, the vortex shedding is not symmetric and becomes chaotic as Reynolds number increases. © All Right Reserved.

关键词： Wakes

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