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Chemisorbed　dimethylammonium　chlorochromate　as　selective　oxidants　for　primary　and　second　aryAlcohols

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Chinese Chemical Letters 1996年第11期7卷 973-974页

作者： zhang, gs Shi, QZ Chen, MF Cai, K HENAN NORMAL UNIV DEPT CHEMXINXIANG 453002PEOPLES R CHINA

Two new reagents. dimethylammonium chlorochromale adsrbed on alumina and silicagel are describe as convenient reagents for efficient oxidation of a variety of primary and secondaryalcohols. These two reagents are very... 详细信息

关键词： selective and aryAlcohols chlorochromate dimethylammonium oxidants primary Chemisorbed

Selenate oxyanion-intercalated NiFeOOH for stable water oxidation via lattice oxygen oxidation mechanism

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Journal of Energy Chemistry 2025年第2期101卷 676-684页

作者： Yijie zhang Weiyi zhang Xiaowen zhang Jinping Li Guang Liu Shanxi Key Laboratory of Gas Energy Efficient and Clean Utilization College of Chemical Engineering and Technology Taiyuan University of Technology Shanxi Research Institute of Huai Rou Laboratory

Transition metal-based compounds can serve as pre-catalysts to obtain genuine oxygen evolution reaction（OER） electrocatalysts in the form of oxyhydroxides through electrochemical ***,the role and existence form of leached oxygen anions are still ***,we selected iron selenite-wrapped hydrated nickel molybdate（denoted as NiMoO/FeSeO） as a pre-catalyst to study the oxyanion *** is surprising to find that SeO2-exists in the catalyst in the form of intercalation,which is different from previous studies that suggest that anions are doped with residual elements after electrochemical activation,or adsorbed on the catalyst *** experiment and theoretical calculations show that the existence of SeO42-intercalation effectively adjusts the electronic structure of NiFeOOH,promotes intramolecular electron transfer and O-O release,and thus lowers the reaction energy *** expected,the synthesized NiFeOOH-SeO only needs 202 and 285 mV to attain 100 and 1000 mA cm-2in 1 M ***,the anion exchange membrane water electrolyzer（AEMWE） consisting of NiFeOOHSeO anode and Pt/C cathode can reach 1 A cm-2at 1.70 V and no significant attenuation within 300 *** findings provide insights into the mechanism,by which the intercalated oxyanions enhance the OER performance of NiFeOOH,thereby facilitating large-scale hydrogen production through AEMWE.

关键词： Anion exchange membrane electrolyzer Industrial current densities Lattice oxygen oxidation Oxyanion intercalation Water splitting

How sediment dredging alters phosphorus dynamics in a lowland rural river?

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Journal of Environmental Sciences 2025年第1期147卷 189-199页

作者： Qimou zhang Jiacong Huang Yulai Ji Jing zhang Shuai zhang Junfeng Gao Key Laboratory of Watershed Geographic Sciences Nanjing Institute of Geography and LimnologyChinese Academy of SciencesNanjing 210008China University of Chinese Academy of Sciences Beijing 10094China

China’s lowland rural rivers are facing severe eutrophication problems due to excessive phosphorus(P)from anthropogenic ***,quantifying P dynamics in a lowland rural river is challenging due to its complex interaction with surrounding areas.A P dynamic model(River-P)was specifically designed for lowland rural rivers to address this *** modelwas coupled with the Environmental Fluid Dynamics Code(EFDC)and the Phosphorus Dynamic Model for lowland Polder systems(PDP)to characterize P dynamics under the impact of dredging in a lowland rural *** on a two-year(2020-2021)dataset from a representative lowland rural river in the Lake Taihu Basin,China,the coupled model was calibrated and achieved a model performance(R^(2)>0.59,RMSE<0.04 mg/L)for total P(TP)*** research in the study river revealed that(1)the time scale for the effectiveness of sediment dredging for P control was~300 days,with an increase in P retention capacity by 74.8 kg/year and a decrease in TP concentrations of 23%after dredging.(2)Dredging significantly reduced P release from sediment by 98%,while increased P resuspension and settling capacities by 16%and 46%,respectively.(3)The sediment-water interface(SWI)plays a critical role in P transfer within the river,as resuspension accounts for 16%of TP imports,and settling accounts for 47%of TP *** the large P retention capacity of lowland rural rivers,drainage ditches and ponds with macrophytes are promising approaches to enhance P retention *** study provides valuable insights for local environmental departments,allowing a comprehensive understanding of P dynamics in lowland rural *** enable the evaluation of the efficacy of sediment dredging in P control and the implementation of corresponding P control measures.

关键词： Lowland rural river Phosphorus Sediment dredging Model ensemble Retention capacity

Analyzing carbon emissions and influencing factors in Chengdu-Chongqing urban agglomeration counties

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Journal of Environmental Sciences 2025年第5期151卷 640-651页

作者： zhang Heng Lu Wenfu Peng Lindan zhang Key Laboratory of the Evaluation and Monitoring of Southwest Land Resources(Ministry of Education) Sichuan Normal UniversityChengdu 610068China The Institute of Geography and Resources Science Sichuan Normal UniversityChengdu 610068China

Majority of carbon emissions originate from fossil energy consumption,thus necessitating calculation and monitoring of carbon emissions from energy *** this study,we utilized energy consumption data from Sichuan Province and Chongqing Municipality for the years 2000 to 2019 to estimate their statistical carbon *** then employed nighttime light data to downscale and infer the spatial distribution of carbon emissions at the county level within the Chengdu-Chongqing urban ***,we analyzed the spatial pattern of carbon emissions at the county level using the coefficient of variation and spatial autocorrelation,and we used the Geographically and Temporally Weighted Regression(GTWR)model to analyze the influencing factors of carbon emissions at this *** results of this study are as follows:(1)from 2000 to 2019,the overall carbon emissions in the Chengdu-Chongqing urban agglomeration showed an increasing trend followed by a decrease,with an average annual growth rate of 4.24%.However,in recent years,it has stabilized,and 2012 was the peak year for carbon emissions in the Chengdu-Chongqing urban agglomeration;(2)carbon emissions exhibited significant spatial clustering,with high-high clustering observed in the core urban areas of Chengdu and Chongqing and low-low clustering in the southern counties of the Chengdu-Chongqing urban agglomeration;(3)factors such as GDP,population(Pop),urbanization rate(Ur),and industrialization structure(Ic)all showed a significant influence on carbon emissions;(4)the spatial heterogeneity of each influencing factor was evident.

关键词： Carbon emissions Chengdu-Chongqing urban agglomeration Spatial autocorrelation Geographically and temporally weighted regression

Automatic and Rapid Throughflow-Based Optimal Design Method for Multi-Stage Axial-Flow Compressors

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Journal of Thermal Science 2025年第1期34卷 77-91页

作者： LEI Fan zhang Xiawen JU Yaping zhang Chuhua Department of Fluid Machinery and Engineering School of Energy and Power EngineeringXi'an Jiaotong UniversityXi'an 710049China State Key Laboratory for Strength and Vibration of Mechanical Structures Xi'an Jiaotong UniversityXi'an 710049China Production and Environmental Department China Huaneng Group.Co.Ltd.Beijing 100031China

Throughflow design has the advantages of less time consumption and large optimization space,and thus is the corner stone of advanced design system of multi-stage axial-flow *** majority of relevant studies were limited to the throughflow inverse designs,and quite few works have been till now devoted to the throughflow optimal *** this work,an automatic and rapid throughflow-based optimal design method is proposed for axial-flow compressors in which a throughflow inverse design solver is embedded in optimal genetic algorithm to improve the design efficiency of axial-flow *** types of design parameters in the throughflow inverse design of axial-flow compressors,i.e.,swirl and shroud curve,are simultaneously used to optimize both the blade shape and flow *** proposed method is validated by the redesign optimization of the benchmark axial-flow compressor NASA Stage 35,and the CFD predictions show that the throughflow-based optimization leads to 1.18% efficiency benefit at design *** proposed method is then utilized to the two-dimensional throughflow optimal design of a large-scale 6.5-stage axial-flow industrial *** optimal design results are confirmed by CFD predictions,indicating that the proposed method can effectively improve the design adiabatic efficiency of the compressors by 1.09% within a few minutes on desk-top *** throughflow design implications are also obtained for advanced axial-flow industrial *** work could enhance the capability of throughflow design method and has engineering application value to explore the throughflow optimization space of multi-stage axial-flow compressors.

关键词： multi-stage axial-flow compressor throughflow design empirical correlations genetic algorithm aerodynamic optimization

Experimental study on failure precursory characteristics and moisture content effect of pre-cracked rocks under graded cyclic loading and unloading

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International Journal of Mining Science and Technology 2025年第2期35卷 249-264页

作者： zhang, Wei zhang, Dongxiao Guo, Weiyao zhang, Baoliang School of Architecture and Engineering Liaocheng University Liaocheng252000 China College of Energy and Mining Engineering Shandong University of Science and Technology Qingdao266590 China

It is important to analyze the damage evolution process of surrounding rock under different water content for the stability of engineering rock mass. Based on digital speckle correlation (DSCM), acoustic emission (AE) and electromagnetic radiation (EMR), uniaxial hierarchical cyclic loading and unloading tests were carried out on sandstones with different fracture numbers under dry, natural and saturated water content, to explore the fracture propagation, failure precursor characteristics and damage response mechanism under the influence of water content effect. The results show that with the increase of water content, the peak stress and crack initiation stress decrease gradually, and the decreases are 15.28%–21.11% and 17.64%–23.04%, respectively. The peak strain and crack initiation strain increase gradually, and the increases are 19.85%–44.53% and 19.15%–41.94%, respectively. The precracked rock with different water content is mainly characterized by tensile failure at different loading stages. However, with the increase of water content, the proportion of shear cracks gradually increases, while acoustic emission events gradually decrease, the dissipative energy and energy storage limits of the rock under peak load gradually decrease, and the charge signal increases significantly, which is because the lubrication effect of water reduces the friction coefficient between crack surfaces. © 2025

关键词： Acoustic emissions

Numerical Simulation of Radiation Transport to Improve Microalgae Cultivation in an Air-Lift Photobioreactor

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Journal of Thermal Science 2025年第1期34卷 62-76页

作者： zhang Xianbin LI Mingjia HUNG Tzuchen zhang Zixun Key Laboratory of Thermo-Fluid Science and Engineering of Ministry of Education School of Energy and Power EngineeringXi'an Jiaotong UniversityXi'an 710049China School of Mechanical Engineering Beijing Institute of TechnologyBeijing 100081China Department of Mechanical Engineering Taipei University of TechnologyTaipei 106344China

A comprehensive numerical model is developed to simulate the growth of microalgae under light/dark cycling *** purpose of this study is to predict the growth rate of Chlorella vulgaris cultivated in photobioreactors(PBRs)in order to improve the light conditions for microalgae and enhance the photosynthetic *** fluid dynamics(CFD)is used to simulate its internal hydrodynamic *** Lagrangian method is employed to track the movement of microalgae *** radiative transfer equation(RTE)is used to obtain light intensity *** combination of light radiation field and microalgae cell motions is used to construct the light history and they are integrated into the model of the photosynthetic units(PSU)to calculate the microalgae growth *** numerical results demonstrate that enhanced light/dark cycling frequency with ordered mixing can promote efficient microalgae *** effect of the vortex flow field generated by the baffles in an air-lift PBR is analyzed for increasing microalgae growth *** using the 1:1 baffle spacing,the biomass production of microalgae is increased by 41.8% compared to the original PBR.

关键词： photobioreactor light distribution particle tracking structure optimization

The optimal control theory——a scientific approach to fundamentally solving control problems

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Science China(Information Sciences) 2025年第1期68卷 389-391页

作者： Huanshui zhang School of Electrical and Automation Engineering Shandong University of Science and Technology School of Control Science and Engineering Shandong University

The maximum principle has bridged mathematical optimization to optimal control,ushering in significant developments and refinements in optimal control theory,notably during the 1960s with the advent of linear quadratic (LQ)control and linear quadratic estimation (LQE).This progression propelled optimal control theory into further advancements,encompassing stochastic control,robust/H-infinity control,model predictive control (MPC),networked control,and reinforcement learning *** control,established upon a rigorous mathematical foundation,extends static optimization theory to dynamic systems,exhibiting scientific essence,unity,and ***,since its inception,optimal control theory has served as an indispensable core role across all control-related domains,including communication-constrained control in networked systems,consensus control,cooperative control,and reinforcement learning control.

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Impulsive thrust strategy for orbital pursuit-evasion games based on impulse-like constraint

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Chinese Journal of Aeronautics 2025年第1期38卷 520-536页

作者： Hongbo WANG Yao zhang Hao LIU Kunpeng zhang School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China National Key Laboratory of Space Intelligent Control Beijing Institute of Control EngineeringBeijing 100094China

This paper proposes a novel impulsive thrust strategy guided by optimal continuous thrust strategy to address two-player orbital pursuit-evasion game under impulsive thrust *** strategy seeks to enhance the interpretability of impulsive thrust strategy by integrating it within the framework of differential game in traditional continuous ***,this paper introduces an impulse-like constraint,with periodical changes in thrust amplitude,to characterize the impulsive thrust ***,the game with the impulse-like constraint is converted into the two-point boundary value problem,which is solved by the combined shooting and deep learning method proposed in this *** learning and numerical optimization are employed to obtain the guesses for unknown terminal adjoint variables and the game terminal ***,the accurate values are solved by the shooting method to yield the optimal continuous thrust strategy with the impulse-like ***,the shooting method is iteratively employed at each impulse decision moment to derive the impulsive thrust strategy guided by the optimal continuous thrust *** examples demonstrate the convergence of the combined shooting and deep learning method,even if the strongly nonlinear impulse-like constraint is *** effect of the impulsive thrust strategy guided by the optimal continuous thrust strategy is also discussed.

关键词： Orbital pursuit-evasion game Differential game Impulsive thrust Deep learning Shooting method