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Ultrastable nickel single-atom catalysts with high activity and selectivity for electrocatalytic CO_(2)methanation

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Nano Research 2023年第7期16卷 8987-8995页

作者： Ling-Chan Tian Jin-Nian Hu Yang Meng Jin-xia Liang chun zhu Jun Li School of Chemistry and Chemical Engineering Guizhou UniversityGuiyang 550025China Department of Chemistry and Guangdong Provincial Key Laboratory of Catalytic Chemistry Southern University of Science and TechnologyShenzhen 518055China Department of Chemistry and Engineering Research Center of Advanced Rare-Earth Materials of Ministry of Education Tsinghua UniversityBeijing 100084China

Electrochemical conversion of CO_(2)into valuable hydrocarbon fuel is one of the key steps in solving carbon emission and energy ***,we report a non-noble metal catalyst,nickel single-atom catalyst(SAC)of Ni_(1)/UiO-66-NH_(2),with high stability and selectivity for electrochemical reduction of CO_(2)to CH_(4).Based on ab initio molecular dynamics(AIMD)simulations,the CO_(2)molecule is at first reduced into CO_(2)-when stably adsorbed on a Ni single atom with the bidentate coordination *** evaluate its activity and selectivity for electrocatalytic reduction of CO_(2)to different products(HCOOH,CO,CH3OH,and CH_(4))on Ni_(1)/UiO-66-NH_(2),we have used density functional theory(DFT)to study different reaction *** results show that CH_(4) is generated preferentially on Ni_(1)/UiO-66-NH_(2)and the calculated limiting potential is as low as-0.24 ***,the competitive hydrogen evolution reaction is unfavorable at the activation site of Ni_(1)/UiO-66-NH_(2)owing to the higher limiting potential of-0.56 ***,the change of Ni single atom valence state plays an important role in promoting CO_(2)reduction to CH_(4).This work provides a theoretical foundation for further experimental studies and practical applications of metal-organic framework(UiO-66)-based SAC electrocatalysts with high activity and selectivity for the CO_(2)reduction reaction.

关键词： single atom catalyst density functional theory CO_(2)reduction metal-organic framework electrocatalysis

Theoretical and experimental investigations on single-atom catalysis:Pt_(1)/FeO_(x) for water-gas shift reaction

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Nano Research 2024年第9期17卷 8627-8637页

作者： Shan-Fei Wang Yangyang Li Haiyan Wang Jin-xia Liang chun zhu Botao Qiao School of Chemistry and Chemical Engineering Guizhou UniversityGuiyang 550025China CAS Key Laboratory of Science and Technology on Applied Catalysis Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China University of Chinese Academy of Sciences Beijing 100049China

Oxide-supported metal single-atom catalysts(SACs)have exhibited excellent catalytic performance for water-gas shift(WGS)***,we report the single-atom catalyst Pt1/FeOx exhibits excellent medium temperature catalytic performance for WGS reactions by the density functional theory(DFT)calculations and experimental *** calculations indicate that H_(2)O molecules are easily dissociated at oxygen vacancies,and the formed*OH and*O are adsorbed on Pt1 single atoms and the adjacent O atoms,*** studying four possible reaction mechanisms,it is found that the optimal WGS reaction pathway is proceeded along the carboxyl mechanism(pathway III),in which the formation of*COOH intermediates can promote the stability of Pt_(1)/FeO_(x) SAC and the easier occurrence of WGS *** energy barrier of the rate-determining step during the entire reaction cycle is only 1.16 eV,showing the high activity for the medium temperature WGS reaction on Pt_(1)/FeO_(x) SAC,which was verified by experimental ***,the calculated turnover frequencies(TOFs)of CO_(2)and H_(2)formation on Pt1/FeOx at 610 K(337℃)can reach up to 1.14×10^(-3)s^(-1)·site^(-1)through carboxyl *** this work,we further expand the application potential of Pt1/FeOx SAC in WGS reaction.

关键词： water-gas shift(WGS)reaction single-atom catalyst(SAC) density functional theory(DFT) thermocatalysis

Feature analysis on US military aircraft engine advanced technology programs

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航空动力学报 2014年第7期29卷 1701-1709页

作者： LIANG chun-hua SUN Ming-xia LIU Hong-xia Shenyang Engine Design and Research Institute Aviation Industry Corporation of China

US military aircraft engine advanced technology programs were overviewed and analyzed from light weight gas generator(LWGG)program initiated in 1960 sthrough integrated high performance turbine engine technology(IHPTET)program started in 1980 s,then to versatile affordable advanced turbine engine(VAATE)*** features and trends were summarized and concluded by literature statistics method,such as teams based on closely corporation among government,industries and academics,goals oriented with national defence strategies and weapon system development requirements,engineering manufacture and development including all relative disciplines and areas,verification measured by technology readiness level,the application extending to military aircraft engine,civilian engine,gas turbine and space vehicle,*** experience and lessons obtained can provide reference and guide for technology research and engineering manufacture and development of military aircraft engines in the world.

关键词： aircraft engine military aircraft engine advanced technology program technology corporation multi-discipline development technology verification

Surface embedded binary Co-Cu hydroxy phosphate over surface of oxy/hydroxides for efficient nitrate reduction to ammonia

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Nano Research 2025年第1期18卷 195-207页

作者： chun zhu Yifei Yang Yike Jing Zhen Zeng Xuesong Yi Wei Sun Fei Yang Key Laboratory of Agro-Forestry Environmental Processes and Ecological Regulation of Hainan Province School of Environmental Science and EngineeringHainan UniversityHaikou 570228China

Electrochemical nitrate reduction reaction(NO3RR)to ammonia is a promising approach to address excess Ncontamination in aqueous environment but suffers from a limited ammonia yield and selectivity due to the low concentration and sluggish *** work reports a three-dimensional porous electrode with binary Co_(2)Cu_(1)hydroxy phosphate embedded into the surface of Ni_(3)Co_(1)oxy/hydroxides(CoCu-PH@NiCo/Ni,“PH”means phosphate-hydroxide),which delivers a yield of 4.13 mg·h^(-1)·cm^(-2)with a high Faraday efficiency of 92.6%under a low nitrate concentration of 40 mM and provide an impressive *** embedded structure of the as-prepared catalyst exhibits unique metal coordination ligands and valence states different from the unitary *** electrochemical in situ infrared spectra and theoretical calculations revealed that the Co sites with the ability to dissociate water molecular to form adsorbed OH*can effectively provide the required protons for the deoxygenation and hydrogenation steps during NO3-conversion,thereby,effectively reducing the energy barrier of the key transition states in the NO3RR process to improve the intrinsic *** demonstrate that the rational design of binary components with the appropriate ability to activate water molecules as well as the threedimensional porous skeletal structure are expected to promote effectively the low-concentration nitrates conversion to ammonia.

关键词： nitrate reduction hydroxy phosphate surface embedded water dissociation active hydroxy adsorbed

Sonographic evaluation of proximal gastric accommodation in patients with functional dyspepsia

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World Journal of Gastroenterology 2013年第29期19卷 4774-4780页

作者： Xiu-Ping Fan Lin Wang Qiang zhu Teng Ma chun-xia xia Ya-Jing Zhou Department of Diagnostic Ultrasound Beijing Tongren Hospital Capital Medical University

AIM: To assess the value of ultrasonography (US) in evaluation of proximal gastric accommodation disorder in patients with functional dyspepsia (FD). METHODS: Between April 2011 and March 2012, 45 patients with FD and 27 healthy volunteers were enrolled in this study. Two-dimensional ultrasound (2DUS) and 3-dimensional ultrasound (3DUS) were performed sequentially to measure proximal gastric area (PGA), maximal proximal gastric diameter (MPGD), and proximal gastric volume (PGV). These values were measured separately in the two groups every other 5 min for a duration of 25 min after the beginning of ingestion of a test meal. Air pocket grading was done separately for images of 2DUS and blocks of 3DUS obtained at five scanning time points. RESULTS: Both PGA and PGV of patients were significantly smaller than healthy controls (P = 0.000 and 0.002, respectively). Comparing the two parameters between the groups at each time point, the differences were also statistically significant (P = 0.000-0.013), except at 10 min for the PGV (P = 0.077). However, no overall difference was found between the groups in the MPGD measurements (P = 0.114), though it was statistically significant at a 20-minute examination point (P = 0.026). A total of 360 sets or blocks of images were obtained for both 2DUS and 3DUS. For the images analyzed by 2DUS, none were excluded because of gastric gas, and 50 (13.9%) and 310 (86.1%) sets were determined as air pockets grades 1 and 2, respectively. For the images analyzed by 3DUS, 23 (6.4%) blocks were excluded from the measurement due to presence of a large fundus air pocket (grade 3); fifty (13.9%) and 287 (79.7%) blocks were also graded as 1 and 2, respectively. CONCLUSION: Measurement of both PGA and PGV by 2DUS and 3DUS could be useful for assessment of the proximal gastric accommodation.

关键词： Functional dyspepsia Gastric accommodation Ultrasonography Diagnosis 2-dimensional ultrasound 3-dimensional ultrasound

LSTM-DPPO based deep reinforcement learning controller for path following optimization of unmanned surface vehicle

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Journal of Systems Engineering and Electronics 2023年第5期34卷 1343-1358页

作者： xia Jiawei zhu Xufang LIU Zhong xia Qingtao School of Weaponry Engineering Naval University of EngineeringWuhan 430033China Qingdao Campus Naval Aviation UniversityQingdao 266041China School of Electronic Engineering Naval University of EngineeringWuhan 430033China

To solve the path following control problem for unmanned surface vehicles(USVs),a control method based on deep reinforcement learning(DRL)with long short-term memory(LSTM)networks is proposed.A distributed proximal policy opti-mization(DPPO)algorithm,which is a modified actor-critic-based type of reinforcement learning algorithm,is adapted to improve the controller performance in repeated *** LSTM network structure is introduced to solve the strong temporal cor-relation USV control *** addition,a specially designed path dataset,including straight and curved paths,is established to simulate various sailing scenarios so that the reinforcement learning controller can obtain as much handling experience as *** numerical simulation results demonstrate that the proposed method has better control performance under missions involving complex maneuvers than trained with limited scenarios and can potentially be applied in practice.

关键词： unmanned surface vehicle(USV) deep reinforce-ment learning(DRL) path following path dataset proximal po-licy optimization long short-term memory(LSTM)

Analysis on capabilities of density-based solvers within OpenFOAM to distinguish aerothermal variables in difusion boundary layer

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Chinese Journal of Aeronautics 2013年第6期26卷 1370-1379页

作者： Shen chun Sun Fengxian xia Xinlin School of Energy Science and Engineering Harbin Institute of Technology School of Power and Energy Science Harbin Engineering University

Open source feld operation and manipulation（OpenFOAM）is one of the most prevalent open source computational fluid dynamics（CFD）*** is very convenient for researchers to develop their own codes based on the class library toolbox within *** recent years,several density-based solvers within OpenFOAM for supersonic/hypersonic compressible flow are coming *** the capabilities of these solvers to capture shock wave have already been verifed by some researchers,these solvers still need to be validated comprehensively as commercial CFD *** boundary layer where diffusion is the dominant transportation manner,the convective discrete schemes＇capability to capture aerothermal variables,such as temperature and heat flux,is different from each other due to their own numerical dissipative characteristics and from viewpoint of this capability,these compressible solvers within OpenFOAM can be validated *** this paper,frstly,the organizational architecture of density-based solvers within OpenFOAM is ***,from the viewpoint of the capability to capture aerothermal variables,the numerical results of several typical geometrical felds predicted by these solvers are compared with both the outcome obtained from the commercial software Fastran and the experimental *** the computing process,the Roe,AUSM＋（Advection Upstream Splitting Method）,and HLLC（Harten-Lax-van Leer-Contact）convective discrete schemes of which the spatial accuracy is 1st and 2nd order are utilized,*** compared results show that the aerothermal variables are in agreement with results generated by Fastran and the experimental data even if the1st order spatial precision is ***,the accuracy of these density-based solvers can meet the requirement of engineering and scientifc problems to capture aerothermal variables in diffusion boundary layer.

关键词： Aerothermal variables Boundary layer Computational fluid dynamics(CFD) Heat flux Open source Supersonic

The density-and isospin-dependent■-formation cross section and its decay width

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Science China(Physics,Mechanics & Astronomy) 2019年第7期62卷 76-81页

作者： QingFeng Li zhu xia Li School of Science Huzhou University Institute of Modern Physics Chinese Academy of Sciences China Institute of Atomic Energy

The energy-, density-, and isospin-dependent ?-formation cross section σ_(Nπ→?)~* and ?-decay width are calculated based on the relativistic BUU approach in which the effective mass splitting of nucleon and ? baryons in isospin-asymmetric matter is considered by the inclusion of the δ meson exchange in the effective Lagrangian density and the density-dependent coupling constants of Hofmann et al. The results show that the σ_(Nπ→?)~* is decreased(increased) moderately with increasing density with(without)the consideration of medium modifications on pion mass. Meanwhile, if the invariant mass of the system is not far from the ?pole mass, the ?-decay width is also weakly dependent on density. The mass splitting effect of differently charged nucleon and ?baryons on σ_(Nπ→?)~* is found to be more obvious than that of pion mesons but much weaker than the mass splitting in the hard ?production channel NN → N?. Further, the largest mass-splitting influence is seen in the π^-p → ?~0 and π^+n → ?^+ channels but not in the production of ?^- and ?^(++) isobars.

关键词： ■-formation cross section decay width symmetry energy

Wetland and habitat dynamics in the evolving landscape of the Middle Yangtze River Basin

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Journal of Geographical Sciences 2025年第1期 88-111页

作者： YANG Peng SUN Kaiya zhu Yanchao xia Jun HUANG Heqing SONG Jingxia SHI xiaorui LU Xixi Hubei Key Laboratory of Regional Ecology and Environmental Change School of Geography and Information Engineering China University of Geosciences Department of Geography National University of Singapore State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University

Wetlands play a critical role in the global environment. The Middle Yangtze River Basin(MYRB), known for its abundant wetland resources, has experienced notable changes resulting from the complex interplay of environmental factors. Therefore, we investigated the spatiotemporal characteristics of wetland ecological quality in the MYRB from 2001 to *** the random forest(RF) regression algorithm and patch-generated land-use simulation(PLUS) model, we forecasted variations in wetland habitat quality and their determinants under the Shared Socioeconomic Pathway-Representative Concentration Pathway(SSPRCP) framework from 2035 to 2095. The main findings are as follows:(1) The RF algorithm was optimal for land-use and land-cover(LULC) classification in the MYRB from 2001 to 2020,when notable changes were observed in water bodies and buildings. However, the forested area exhibited an increase and decrease of 3.9% and 1.2% under the SSP1-2.6 and SSP5-8.5 scenarios, respectively, whereas farmland exhibited a diminishing trend.(2) Wetlands were primarily concentrated in the central and eastern MYRB, with counties in the southwest exhibiting superior ecological-environmental quality from 2001 to 2020. Notably,wetland coverage revealed significantly high level, significant changes, frequent but relatively minor changes under the SSP1-2.6, SSP2-4.5, and SSP 5-8.5 scenarios, respectively.(3)Regions with lower habitat quality were primarily concentrated in urbanized areas characterized by frequent human activities, indicating a clear degradation in habitat quality across different scenarios. In conclusion, we established a foundational framework for future investigations into the eco-hydrological processes and ecosystem quality of watersheds.

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