检索结果-内蒙古大学图书馆

A direct polymeric carbon nitride/tungsten oxide Z-scheme heterostructure for efficient photocatalytic hydrogen generation via reforming of plastics into value-added chemicals

引用

Rare Metals 2024年第8期43卷 3771-3783页

作者： Rui-Zhe Wang Zhi Lin Yi-Qing Wang Kai-Ni Zhang Ge-Hong Zhang Jie Zhang Samuel S.Mao Shao-Hua Shen International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi'an Jiaotong UniversityXi'an 710049China School of Civil and Architecture Engineering Xi'an Technological UniversityXi'an 710021China Department of Mechanical Engineering University of California at BerkeleyBerkeleyCA94720USA

To promote charge transfer and separation for efficient photocatalysis,a direct Z-scheme heterostructure was constructed by coupling polymeric carbon nitride(PCN) and WO_(3).Interestingly,the obtained PCN/WO_(3)Z-scheme heterostructure could photocataly tic ally produce hydrogen and value-added chemicals(e.g.,formate and acetate) by reforming of plastic polylactic acid(PLA) in alkaline aqueous *** optimizing WO_(3) contents and reaction conditions,the obtained PCN/WO_(3)heterostructure exhibits much increased photocatalytic activity for PLA photoreforming under visible light,with hydrogen evolution rate reaching 402.90 μmol·g~(-1)·h~(-1),which is 3.5 times that of *** is revealed that the Z-scheme charge transfer between PCN and WO_(3) mainly contributes to the promoted charge separation and thus the improved photocatalytic ***,with h+and·OH experimentally evidenced as the predominant active species,a possible reaction pathway for the reforming of PLA into value-added chemicals(e.g.,formate and acetate)over PCN/WO_(3) Z-scheme heterostructure is cleared by monitoring the reaction intermediates and *** work paves a carbon neutrality and scalable route toward the synergistical production of hydrogen and value-added chemicals by utilizing and recycling plastic waste.

关键词： Carbon nitride Z-scheme heterojunction Plastic waste conversion Photocatalytic H_(2)production Value-added chemicals

来源：评论

学校读者我要写书评

暂无评论

Uncertainty analysis of molten corium In-Vessel Retention under External Reactor Vessel Cooling

引用

International Journal of Advanced Nuclear Reactor Design and Technology 2023年第4期5卷 159-167页

作者： Wu, Shihao Wang, Dong Zhang, Yapei Zhou, Yukun Tian, Wenxi Qiu, Suizheng Su, G.H. School of Nuclear Science and Technology Shaanxi Engineering Research Center of Advanced Nuclear Energy State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

External Reactor Vessel Cooling (ERVC) is a key measure to realize molten corium In-Vessel Retention (IVR). The uncertainty of severe accident in core leads to the uncertainty of molten pool parameters in lower head, which may threat the reliability of successful implementation of IVR. In this study, an uncertainty analysis is employed to ensure the reliability of ERVC technology to IVR with the final two-layer molten pool configuration of AP1000.600 simulations are performed to determine the effect of five key parameters. As long as parameters are within high probability density range, lower head can remain intact, and safety margin is greater than 15 %. For influence level and correlation of parameters, the order on metal layer is: Decay heat > Fe mass > UO2 mass > Zr oxidation fraction > Emissivity of metal layer. The results can provide guidance for subsequent research direction and optimal design of mitigation measures. © 2024 Xi'an Jiaotong University

关键词： Uncertainty analysis

来源：评论

学校读者我要写书评

暂无评论

N and O vacancies regulation over semiconductor heterojunction to synergistically boost photocatalytic hydrogen peroxide production

引用

Journal of Materials Science & Technology 2024年第29期196卷 237-247页

作者： Chaoqian Ai Bing Luo Chunyang Zhang Yadi Wang Baoyuan Wang Lijing Ma Dengwei Jing International Research Center for Renewable Energy&State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an 710049China School of Chemical Engineering and Technology Xi’an Jiaotong UniversityXi’an 710049China Department of Chemical Engineering School of Water and Environment&Key Laboratory of Subsurface Hydrology and Ecology in Arid AreasMinistry of Education Chang’an UniversityXi’an 710054China

Defect engineering represents a potent strategy for the modification of electronic properties by introducing atomic vacancies in ***,the synergistic enhancement attributable to different types of atomic vacancies within a heterojunction,as well as their underlying mechanisms,remains sparsely ***,the flexible g-C_(3)N_(4)materials with varying nitrogen vacancies were prepared via a facile calcination method under different atmospheric conditions and then composited with CeO_(2)nanocubes to construct Z-scheme *** was observed that CeO_(2)has abundant O vacancies,and the g-C_(3)N_(4)form tertiary nitrogen defects at the center of the heptazine units under an NH3 atmosphere *** resulting enhancement in the interfacial built-in electric field,coupled with the synergistic effect of O and N vacancies within the Z-scheme heterojunction,has been demonstrated to significantly enhance charge transfer *** results in an optimized photoactivity with a H_(2)O_(2)generation rate of 2.01 mmol g^(-1)h^(-1).This work opens an avenue for constructing and optimizing the heterogeneous photocatalysts by defect engineering technology,and provides deep insight to understand the nature of vacancy engineering in designing effective catalysts for solar energy conversion.

关键词： Photocatalysis H_(2)O_(2) production Z-scheme Defect engineering Synergy effect

来源：评论

学校读者我要写书评

暂无评论

Laminar Flame Instability of n-Hexane,n-Octane,and n-Decane in Spherical Expanding Flames

引用

Journal of Thermal Science 2024年第3期33卷 1189-1199页

作者： YIN Geyuan HU Erjiang LI Xiaotian LV Xin HUANG Zuohua State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an710049China United Automotive Electronic Systems Co. LtdShanghai201206China Chongqing Changan Automobile Co. Ltd.Chongqing401120China

This paper focuses on the laminar flame instability of three high molecular weight n-alkanes,namely n-hexane,n-octane,and *** experiment was carried out in a constant volume combustion bomb to get the flame *** critical radius under different conditions was extracted using the image processing *** with the existing critical Peclet number theory,the dominant factors of flame instability under current conditions for three n-alkanes can be figured ***,the average cell size(equivalent cell radius,R_(cell))was extracted to provide quantitative analysis of the flame cellular structure,based on the method developed in this *** theoretical R_(cell)were also calculated and compared with the experimental results to validate the proposed method.

关键词： cellular instability equivalent cell radius critical Peclet number spherical flame

来源：评论

学校读者我要写书评

暂无评论

Numerical simulation and structural optimization of spiral finned tube thermal energy storage

引用

International Journal of Advanced Nuclear Reactor Design and Technology 2023年第3期5卷 123-136页

作者： Ma, Yunfei Meng, Yu Li, Jingyu Chen, Weixiong Yang, Xiaohu Li, Shaodan Chong, Daotong Yan, Junjie State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China Wuhan Second Ship Design and Research Institute Wuhan430205 China

Thermal energy storage (TES) has emerged as a promising solution to enhance nuclear safety by passively removing decay heat during reactor shutdown and accidents, thus preventing overheating of the reactor core and protecting the integrity of containment barriers. The research of TES with different structures has broad application prospects and practical significance. In this study, the melting process of phase change material (PCM) in various TES structures was simulated by the numerical simulation method in two and three dimensions. The mechanism of gravity-driven natural convection enhancing heat transfer was revealed. The effects of different TES structures, fin pitch, fin height, and fin thickness on heat transfer performance were studied. The results showed that many vortices formed by liquid PCM are the main reason for enhancing the natural convection. Adding fins could greatly accelerate the heat storage process. The melting time of PCM in annular and spiral finned tube TES was 47.3% and 61.3% less than that in smooth tube TES, respectively. In the present study, the heat transfer effect was enhanced as the spiral fin pitch became small, the fin height increased and the fin thickness increased. Two opposite effects of fin structure on the natural convection were revealed: (1) positive effect provided by heat transfer enhancement and (2) negative effect produced by blockage. © 2023 Xi'an Jiaotong University

关键词： Phase change materials

来源：评论

学校读者我要写书评

暂无评论

Vapor-liquid equilibrium of H2/CO2and H2/N2/CO2mixture, the liquefaction technology related to the supercritical water gasification products 8

Vapor-liquid equilibrium of H2/CO2and H2/N2/CO2mixture, the ...

引用

8th International Conference on Smart and Sustainable Technologies, SpliTech 2023

作者： Wu, Hongtu Jin, Hui Xi'an Jiaotong University State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Shaanxi Xi'an710049 China

ISBN: (纸本)9789532901283

In this paper, the dew point and liquid phase composition of H2/CO2 and H2/CO2/N2 mixtures at phase equilibrium calculated by PR-BM equation and Van Der Waal mixing rule with commercial MATLAB software are introduced, it is of theoretical significance for the wide application of the products of supercritical water gasification. First, the results obtained by the self-programming code are verified with the experimental data, the experimental data and simulation results of two kinds of CO2/H2 mixtures and two kinds of CO2/N2/H2 mixtures were compared. The average percentage deviation was 2.69%, 4.05%, 2.22%, 1.20%, respectively. Thus the absolute deviations of the mixtures are within the acceptable range, therefore, the model proposed in this paper can well predict the dew point of the mixtures composed of H2/CO2 or H2/CO2/***, the dew point and the CO2 content in the liquid phase of common H2/CO2 and H2/CO2/N2 vapor mixtures in supercritical water gasification products were predicted, and a series of analysis and discussion were conducted on the predicted results finally. © 2023 University of Split, FESB.

关键词： Carbon dioxide

来源：评论

学校读者我要写书评

暂无评论

Impacts of Startup,Shutdown and Load Variation on Transient Temperature and Thermal Stress Fields within Blades of Gas Turbines

引用

Journal of Thermal Science 2022年第3期31卷 727-740页

作者： CAI Liuxi HOU Yanfang LI Fang LI Yun WANG Shunsen MAO Jingru School of Chemical Engineering and Technology Xi’an Jiaotong UniversityXi’an710049China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an710049China

Based on the actual operation parameters and temperature-dependent material properties of a gas turbine unit,composite cooling blade model and corresponding reliable boundary conditions were *** thermal-fluid-solid coupling simulations were then comprehensively conducted to analyze the transient flow and the temperature field of the blade under startup,shutdown,and variable loads *** with the obtained transient temperature data,the non-linear finite element method was exploited to examine the effect of these transient operations on the turbine blade thermal stress *** show that the temperature and pressure on the blade surface increase with the load level and vice *** the startup process progresses,the film cooling effectiveness and the heat convection of airflows inside the blade continuously grow;high-temperature areas on the pressure surface and along the trailing edge of the blade tip gradually *** high-temperature zones with the maximum of 1280 K are generated at the air inlet and outlet of the blade platform and the leading edge of the blade *** high thermal stresses detected on the higher temperature side of the temperature gradient are commonly generated in places with large temperature gradients and significant geometry *** the startup/shutdown process,the rate of increase/decrease of the thermal stress is positively correlated with the load variation rate.A slight variation rate of the load(1.52%/min)can lead to an apparent alteration(41%)to the thermal *** operations under action of the variable load,although thermal stress is less sensitive to the load variation,the rising or falling rate of the exerted load still needs to be carefully controlled due to the highly leveled thermal stresses.

关键词： composite cooling blade thermal-fluid-solid coupling method transient temperature field load variation thermal stress

来源：评论

学校读者我要写书评

暂无评论

NUMERICAL SIMULATION OF SINGLE/TWO-PHASE flow IN A STRATIFIED POROUS BED 31

NUMERICAL SIMULATION OF SINGLE/TWO-PHASE FLOW IN A STRATIFIE...

引用

2024 31st International Conference on Nuclear engineering, ICONE 2024

作者： Bouloudenine, Aimad Li, Liangxing Xiang, Zutao Shi, Shang Bakar, Muhammad Abu Xi’an Jiaotong University State Key Laboratory of Multiphase Flow in Power Engineering Xianning West Road 28 Xi’an City710049 China

ISBN: (纸本)9780791888292

This study investigates the coolability of debris beds formed from Fuel-Coolant Interactions (FCI) within nuclear reactors, a critical safety concern when cooling systems fail, leading to significant core melting in light-water reactors. The research focuses on understanding the flow dynamics within two-layer stratified porous beds, which develop from the mixture of corium and coolant, particularly around the interface between layers. Using ANSYS Fluent software, numerical simulations were conducted to estimate velocity profiles and pressure drops across a stratified porous structure. The Euler-Euler two-fluid model was employed alongside the k-ω-based Shear Stress Transport (SST) turbulence model to separately model turbulence for each phase. The results reveal that lateral flow dynamics are significant as fluids traverse through the porous media, affecting pressure drops across layers with varying permeabilities. Specifically, the pressure drops across the lower-permeability layer decrease while that across the higher-permeability layer increases, highlighting the influence of lateral flows between layers of different particle sizes due to variations in porosity. This lateral flow is most likely formed during the initial stages of fluid movement through the bed. The study underscores the importance of understanding these flow characteristics for both single/two-phase flow to enhance the safety and design of nuclear reactors by improving debris bed coolability predictions. Copyright © 2024 by ASME.

关键词： Computational fluid dynamics

来源：评论

学校读者我要写书评

暂无评论

TiO_(2) nanorods based self-supported electrode of 1T/2H MoS_(2) nanosheets decorated by Ag nano-particles for efficient hydrogen evolution reaction

引用

Chinese Chemical Letters 2023年第11期34卷 355-359页

作者： Changzheng Lin Yunpeng Liu Yaxing Sun Zhenyu Wang Hao Xu Mingtao Li Jiangtao Feng Bo Hou Wei Yan Department of Environmental Science&Engineering Xi’an Jiaotong UniversityXi’an 710049China School of Physics and Astronomy Cardiff UniversityThe ParadeCardiffCF243AAWalesUnited Kingdom State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an 710049China International Research Center for Renewable Energy(IRCRE) State Key Laboratory of Multiphase Flow in Power Engineering(MFPE)Xi’an Jiaotong UniversityXi’an 710049China

Molybdenum disulfide(MoS_(2))has shown significant promise as an economic hydrogen evolution reaction(HER)catalyst for hydrogen generation,but its catalytic performance is still lower than noble metalbased ***,a silver nanoparticles(Ag NPs)-decorated 1T/2H phase layered MoS_(2) electrocatalyst grown on titanium dioxide nanorod arrays(Ag NPs/1T(2H)MoS_(2)/TNRs)was prepared through acid-tunable ammonium ion *** advantage of MoS_(2) layered structure and crystal phase controllability,as-prepared Ag NPs/1T(2H)MoS_(2)/TNRs exhibited ultrahigh HER ***-proposed strategy combines facile hydrogen desorption(Ag NPs)with efficient hydrogen adsorption(1T/2H MoS_(2))effectively circumventes the kinetic limitation of hydrogen desorption by 1T/2H MoS_(2).The as-prepared Ag NPs/1T(2H)MoS_(2)/TNRs electrocatalyst exhibited excellent HER activity in 0.5 mol/L H2SO4 with low overpotential(118 mV *** hydrogen electrode(RHE))and small Tafel slope(38.61 mV/dec).The overpotential exhibts no obvious attenuation after 10 h of constant current ***-principles calculation demonstrates that as-prepared 1T/2H MoS_(2) exhibit a large capacity to store *** protons can be subsequently transferred to Ag NPs,which significantly increases the hydrogen coverage on the surface of Ag NPs in HER process and thus change the rate-determining step of HER on Ag NPs from water dissociation to hydrogen *** study provides a unique strategy to improve the catalytic activity and stability for MoS_(2)-based electrocatalyst.

关键词： Molybdenum disulfide Silver nanoparticles Hydrogen evolution reaction Density functional theory Hydrogen spillover

来源：评论

学校读者我要写书评

暂无评论

Unconventional energetics of small vacancy clusters in BCC high-entropy alloy Nb_(0.75)ZrTiV_(0.5)

引用

Journal of Materials Science & Technology 2023年第15期146卷 61-71页

作者： Tan Shi Xi Qiu Yundi Zhou Sixin Lyu Jing Li Dan Sun Qing Peng Yong Xin Chenyang Lu School of Nuclear Science and Technology Xi’an Jiaotong UniversityXi’an 710049China Nuclear Power Institute of China Chengdu 610213China State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Engineering Sciences University of Chinese Academy of SciencesBeijing 100049China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an 710049China

The stability of small vacancy clusters including divacancy,trivacancy and tetravacancy has been studied in body-centered cubic high-entropy alloy Nb_(0.75)ZrTiV_(0.5) in structures of random solid solution and short-range order by first-principles calculations and molecular dynamics *** from conventional body-centered cubic metals,the tightly bound configurations have a lower structural stability and are not preferred energetically in the studied high-entropy *** of vacancy configurations leads to vacancy-atom exchanges that favor less compact *** formation energy of small vacancy clusters is much smaller than its constituent elements of Nb and V due to the large structural adjustment induced by severe local lattice *** difference in local lattice distortion and elemental arrangement in the vacancy neighborhood leads to significant site-to-site variation in vacancy cluster energy and *** formation energy has a strong correlation with the local energy state of the vacancy configuration and the extent of structural *** to random solid solution,the structure of short-range order has a higher stability for the most compact cluster configurations and tends to have higher vacancy cluster formation *** to classical molecular dynamics simulations of cluster diffusion at high temperature,the studied high-entropy alloy has a higher probability of cluster dissociation compared to Nb and *** unconventional energetics of small vacancy clusters is expected to have a profound impact on their generation,diffusion,dissociation,coalescence,as well as the defect microstructure evolution during irradiation.

关键词： Refractory high-entropy alloys Small vacancy clusters First-principles calculations Defect energetics Radiation defect evolution

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：