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Bifunctional organocatalyst-catalyzed dynamic kinetic resolution of hemiketals for synthesis of chiral ketals via hydrogen bonding control

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Chinese Chemical Letters 2025年第1期36卷 248-252页

作者： meng Shan Yongmei Yu mengli Sun Shuping Yang mengqi wang Bo Zhu junbiao chang State key Laboratory of Antiviral Drugs Pingyuan LaboratoryNMPA Key Laboratory for Research and Evaluation of Innovative DrugSchool of Chemistry and Chemical EngineeringHenan Normal UniversityXinxiang 453007China

Herein,we report the dynamic kinetic resolution asymmetric acylation ofγ-hydroxy-γ-perfluoroalkyl butenolides/phthalides catalyzed by amino acid-derived bifunctional organocatalysts,and a series of ketals were obtained in high yields(up to 95%)and excellent enantioselectivities(up to 99%).In terms of synthetic utility,the reaction can be performed on a gram scale,and the product can be converted into potential biological nucleoside analog.

关键词： Bifunctional organocatalyst Dynamic kinetic resolution Hemiketal Chiral ketals Hydrogen bonding

Three-dimensional line-of-sight-angle-constrained leader-following cooperative interception guidance law with prespecified impact time

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Chinese journal of Aeronautics 2025年第1期38卷 491-506页

作者： Hao YOU Xinlong chang jiufen ZHAO Rocket Force University of Engineering Xi’an 710025China

To address the problem of multi-missile cooperative interception against maneuvering targets at a prespecified impact time and desired Line-of-Sight(LOS)angles in ThreeDimensional(3D)space,this paper proposes a 3D leader-following cooperative interception guidance ***,in the LOS direction of the leader,an impact time-controlled guidance law is derived based on the fixed-time stability theory,which enables the leader to complete the interception task at a prespecified impact ***,in the LOS direction of the followers,by introducing a time consensus tracking error function,a fixed-time consensus tracking guidance law is investigated to guarantee the consensus tracking convergence of the ***,in the direction normal to the LOS,by combining the designed global integral sliding mode surface and the second-order Sliding Mode Control(SMC)theory,an innovative 3D LOS-angle-constrained interception guidance law is developed,which eliminates the reaching phase in the traditional sliding mode guidance laws and effectively saves energy ***,it effectively suppresses the chattering phenomenon while avoiding the singularity issue,and compensates for unknown interference caused by target maneuvering online,making it convenient for practical engineering ***,theoretical proof analysis and multiple sets of numerical simulation results verify the effectiveness,superiority,and robustness of the investigated guidance law.

关键词： Three-dimensional cooperative interception Leader-following missiles Prespecified impact time LOS-angle-constrained Fixed-time stability Global integral sliding mode

Omnidirectional simulation analysis of thermomechanical coupling mechanism in inertia friction welding of Ni-based superalloy

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Chinese journal of Aeronautics 2025年第1期38卷 202-216页

作者： chang-an LI Guoliang QIN Hao wANG School of Materials Science and Engineering Shandong UniversityJinan 250061China

The coupling between heat and pressure is the kernel of inertia friction welding(IFw)and is still not fully understood.A novel 3D fully coupled finite element model based on a plastic friction pair was developed to simulate the IFw process of a Ni-based superalloy and reveal the omnidirectional thermo-mechanical coupling mechanism of the friction *** numerical model successfully simulated the deceleration,deformation processes,and peak torsional moments in IFw and captured the evolution of temperature,contact pressure,and *** simulated results were validated through measured thermal history,optical macrography,and axial *** results indicated that interfacial friction heat was the primary heat source,and plastic deformation energy only accounted for 4%of the *** increase in initial rotational speed and friction pressure elevated the peak temperature,reaching a maximum of 1525.5k at an initial rotational speed of 2000 r/min and friction pressure of 400 *** interface heat generation could form an axial temperature gradient exceeding 320k/*** radial inhomogeneities of heat generation and temperature were manifested in a concentric ring distribution with maximum heat flux and temperature ranging from 2/5 to 2/3 *** radial inhomogeneities were caused by increasing linear velocity along the radius and an opposite distribution of contact pressure,which could reach 1.7 times the set pressure at the *** circumferential inhomogeneity of thermomechanical distribution during rotary friction welding was revealed for the first time,benefiting from the 3D *** deflection and transformation of distribution in contact pressure and Mises stress were indicators of plastic deformation and transition of quasi-steady state *** critical Mises stress was 0.5 times the friction pressure in this *** presented modeling provides a reliable insight into the thermo-mechanical coupling mechanism of IFw and lays a solid found

关键词： Inertia friction welding Thermo-mechanical coupling Inhomogeneity Numerical simulation Ni-based superalloy

Effects of Paper Mill Sludge on Potassium, Sodium, Calcium, and Magnesium Concentrations in Different Soybean Cultivars

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Pedosphere 2005年第1期15卷 84-94页

作者： YANXiang-kui k.w.chang H.L.XU NationalInstituteforAgro-EnvironmentalSciences Tsukuba-shi305-8506Japan／／GansuAgriculturalUniversityLanzhou730070China AgrochemistryDepartment ChungnamNationalUniversityKung-DongTaejon305-764Korea InternationalNatureFarmingResearchCenter 5632HataNagano390-1401（Japan）

A field experiment was conducted on a sandy loam soil at an Experimental Farm in Taejon, South korea, to determine the effects of paper mill sludge compost application rates on k, Na, Ca and Mg concentrations of soybean (Glycine max (L.) Merr.) aboveground tissues and the genotypic effects on the concentrations of these elements. Sludge compost treatments of 0, 75, and 150 t ha-1 were applied to 30 diverse soybean cultivars. Concentrations of k, Na, Ca, and Mg in aboveground tissues harvested 69 days after …

关键词： calcium magnesium paper mill sludge potassium sodium soybean

Release characteristics of arsenic from sediments and its source or sink competition with phosphorus:A case of a great lake with grass-algae alternation

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journal of Environmental Sciences 2025年第3期149卷 278-287页

作者： Shuhang wang Yongsheng chang wei Huang Dianhai Yang Feifei Che State key Laboratory of Pollution Control and Resource Reuse College of Environmental Science and EngineeringTongji UniversityShanghai 200092China College of Environmental Science and Engineering Donghua UniversityShanghai 201620China National Engineering Laboratory for Lake Pollution Control and Ecological Restoration Chinese Research Academy of Environmental SciencesBeijing 100012China

The arsenic(As)release from sediments in great lakes is affected by various *** this study,the characteristics of As release fromsediments was investigated,and the As sources and sinks with the strengths in sediments from different areas(grass-type,algae-type,and grass-algae alternation areas)in great shallow lakes(Taihu Lake,China)were analyzed,and the influence of P competition in the process of As release was also *** results showed that changing trend of the values of equilibrium As concentration in sediments were consistent with the regional changes(0 to 28.12μg/L),and the sediments from algaetype areas had the higher *** sediments from western lake and northwest lake bay were a strong As and a weak P source,and the north lake bay had the opposite trend of these two *** P source competition with As from the sediments occurred in algae-type *** grass-type areas had strong As and P retention capacities,indicating a sink role of sediment with high As and P sorption *** degree of As and P saturation had similar trend in sediments,and the grass-type areas had the higher values,18.3%-21.4%and 15.31%-20.34%,*** analysis results showed that most of As release contribution was from the bottom(30-50 cm)sediments,and the surface(0-10 cm)sediments from algae-type areas contributed more to the overlying water than other region.

关键词： Arsenic Phosphorus Sediment Source and sink Contribution

Long-duration aqueous Zn-ion batteries achieved by dual-salt highly-concentrated electrolyte with low water activity

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journal of Energy Chemistry 2025年第2期101卷 778-785页

作者： Lvzhang jiang Lingbo Yao Gege wang chang Liu Xiaowei Chi Yu Liu Shanghai Institute of Ceramics Chinese Academy of Sciences University of Chinese Academy of Sciences

Aqueous Zn-ion batteries have attracted much attention due to their unique high safety and low-cost ***,their practical applications are at a slow pace due to their short cycle life,which fundamentally results from the instability of the positive/negative electrode interface in the traditional dilute aqueous electrolytes with high water *** highly concentrated electrolyte（HCE）has been considered as an effective *** previous studies of single salt-based HCE（SSHCE）,herein,a new dual-salt HCE（15 m ZnCl2+10 m NH4NH2SO3DS-HCE） was proposed for the first ***-HCE was proven to simultaneously possess higher conductivity than traditional dilute electrolytes and ultralow water activity of SS-HCE by the regulation of dual high-concentration salts on the solvation structure,which renders the Zn‖Zn symmetric cell the record-long cycling life of 2200 h compared with those with SS-HCE（30 m ZnCl2,300 h） and other reported ***,the Zn‖NH4V4O10full cell with DS-HCE demonstrated impressed rate capability within a wide-range current densities from 0.1 to 10 A ***,at the high current density of 5 A g-1,the full cell shows almost100% capacity retention after 4000 cycles,which indicates the promising future of the DS-HCE system for long-duration aqueous Zn-ion batteries.

关键词： Ammonium vanadate Aqueous zinc battery Cycling stability Electrolyte

Effects of rejuvenation heat treatment on microstructure and creep property of a Ni-based single crystal superalloy

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journal of Materials Science & Technology 2021年第1期60卷 206-215页

作者： k.j.Tan X.G.wang j.j.Liang j.meng Y.Z.Zhou X.F.Sun Superalloys Division Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Department of Materials Science and Engineering University of Science and Technology of ChinaHefei 230026China

Both surface and internal microstructures of a second-generation Ni-based single crystal(SX) superalloy were studied after creep and rejuvenation heat treatment(RHT).It is indicated that the microstructures,such as the dislocation network,the γ phase and the γ' phase,can be recovered to those after the standard heat treatment(SHT).It is found that RHT affected zone(RAZ) formed at the surface is composed of theγ'-free layer,the transition layer and the recrystallization(RX),which are less than 20 μm in depth *** depth of the RAZ doesn't affect the properties of the *** morphology of γ' phase at the RAZ is related to the composition of the *** average creep life after RHT is close to the average life after *** is concluded that RHT could effectively repair SX parts and increase the total life of the sample after a damage by creep.

关键词： Superalloys Rejuvenation heat treatment Microstructure Creep property

Understanding amorphous PrO_(x)-based N-doped carbon catalyst as an efficient electrocatalyst for oxygen reduction reaction

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journal of Rare Earths 2025年第1期43卷 73-80,I0003页

作者： Xiao Man Ying chang Shaohong Guo Meilin jia jingchun jia Inner Mongolia key Laboratory of Green Catalysis and Inner Mongolia Collaborative Innovation Center for water Environment Safety College of Chemistry and Environmental ScienceInner Mongolia Normal UniversityHohhot010022China

The development of an e fficacious and easily prepared no nprecious metal electrocatalyst is crucial fo r the oxygen reduction reaction(ORR).This work used a dual template method to prepare the amorphous rare earth-based catalyst PrO_(x)-NC,and optimized the calcination temperature and *** PrO_(x)-NC-900 catalyst has high durability and activity and exhibits superior ORR performance in alkaline electrolytes with an onset potential(E_(0))of 0.96 V and a half-wave potential(E_(1/2))of 0.85 *** research results indicate that the ORR performance of rare earth oxide composite carbon catalysts can be improved by adjusting oxygen vacancies(Ov).In addition,high specific surface area,N rich defect *** oxygen vacancies,and the synergistic effect of oxygen vacancies and N-doped carbon interfacial layer play a significant part in the enhancement of *** performance of the zinc air battery assembled with PrO_(x)-NC-900 is significantly improved,and rare earth oxides and carbon frameworks originating from metal organic frameworks(MOFs)contribute to the oxygen electrocatalyst and electron transfer rate of the zinc air *** catalyst provides promising information for the development of rare earth metal oxide nanostructures as potential candidate materials for ORR in alkaline media.

关键词： Rare earths Metal-organic framework Oxygen reduction reaction Zn-air batteries

Status analysis on sputtering and erosion evaluation methods of ion optic systems

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Chinese journal of Aeronautics 2025年第1期38卷 254-270页

作者： Long MIAO Tongxun YANG Zhengxi ZHU chang LU Zhiwen wU Ningfei wANG School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China Chongqing Innovation Center Beijing Institute of TechnologyChongqing 404100China Advanced Aerospace Power and Energy Research Center Beijing Institute of TechnologyZhuhai 519088China

In the past few decades,ion engines have been widely used in deep-space propulsion and satellite *** aim of extending the thruster lifetime is still one of the most important parts during the design stage of ion *** one of the core components of ion engine,the grid assembly of ion optic systems may experience long-term ion sputtering in extreme electro-thermal environments,which will eventually lead to its structural and electron-backstreaming *** this paper,the current studies of the grid assembly erosion process are systematically analyzed from the aspects of sputtering damage process of grid materials,numerical simulations,and measurements of erosion characteristics of grid *** advantages and disadvantages of various erosion prediction models are highlighted,and the key factors and processes affecting the prediction accuracy of grid assembly erosion patterns are *** different types of experimental methods of grid assembly erosion patterns are *** analysis in this paper is of great importance for selecting the sputter-resistant grid materials,as well as establishing the erosion models and measurement methods to accurately determine the erosion rate and failure modes of grid ***,the working conditions and structure parameters of ion optic systems could be optimized based on erosion models to promote the ion engine lifetime.

关键词： Electric propulsion Ion optic systems Sputtering yield Erosion characteristics Erosion pattern measurement Lifetime evaluation