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Journal of Magnesium and Alloys 2022年第5期10卷 1256-1267页

作者： y.J.Wan y.Zeng y.c.dou D.c.Hu X.y.Qian Q.Zeng K.X.Sun G.F.Quan Key Laboratory of Advanced Technologies of Materials Ministry of EducationSchool of Material Science and EngineeringSouthwest Jiaotong UniversityChengdu 610031China college of Materials Science and Engineering Sichuan University of Science and EngineeringZigong 643000China Department of Materials The University of ManchesterOxford RoadManchester M139PLUnited Kingdom

Aging prior to twinning deformation was proposed to alter the precipitate orientation of the plate-shapedβ-MgAlfrom(0002)basal planes(named basal plates)to■prismatic planes(named prismatic plates)in AZ31 Mg *** experimental results showed that the compressive yield strength(cyS)of the sample containing prismatic plates increased 40 MPa and the compression ratio raised by 22%compared to that containing basal *** underlying strengthening mechanism was analyzed via a yield strengthen(yS)model with a function of grain size,precipitate characters(size,oritention,fraction)and Schmid factor(SF).It revealed that the improvement of cyS was mainly attributed to the altered precipitate orientation and refined grain size produced by twinning ***,the prismatic plates always have a stronger hardening effect on basal slip than basal plates under the same varites of precipitate diameter and ***,the decreased cRSS ratio of prismatic slip to basal slip revealed that the activity of non-basal slip in Mg alloy might be *** activated slip systems provided more mobile dislocations,contributing to the large compression ratio of the Mg rolled sheet with prismatic plates.

关键词： Precipitate orientation Precipitation strengthening Grain boundary strengthening yield strength model

A novel three-inflection-point sliding mode control framework for forward-tilting morphing aerospace vehicle with performance constraints and actuator faults

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chinese Journal of Aeronautics 2024年第8期37卷 293-310页

作者： Xinkai LI Lei dou Hongli ZHANG yue MENG School of Electrical Engineering Xinjiang UniversityUrumqi 830047China

A prescribed performance control scheme based on the three-inflection-point hyperbolic function and predefined time performance function is proposed to solve the trajectory tracking problem of the forward-tilting morphing aerospace vehicle with time-varying actuator *** accurately estimate the loss degree of actuator faults,an immersion and invariance observer based on the predefined time dynamic scale factor is designed to estimate and compensate it.A composite dynamic sliding mode surface is designed using a three-inflection-point hyperbolic function,and a novel three-inflection-point sliding mode control framework is *** convergent domain of the sliding manifold is adjusted by parameters,and the system error convergence is controllable.A transfer function is designed to eliminate the sensitivity of the three-inflection-point hyperbolic sliding mode to the unknown initial state,and combined with the barrier Lyapunov function,and the performance constraint of the system is *** global asymptotic stability of the system is demonstrated using a strict mathematical *** effectiveness and superiority of the proposed control scheme are proven by simulation experiments.

关键词： Morphing aerospace vehicle Actuator faults Immersion and invariance Three-inflection-point sliding mode control Prescribed performance control

In-situ UV-Vis Spectroscopy of Trisulfur Radicals in Lithium-Sulfur Batteries

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chemical Research in chinese Universities 2024年第2期40卷 279-286页

作者： dou Renju WANG Qin REN Xiaoyan LU Lehui School of Applied chemistry and Engineering University of Science and Technology of ChinaHefei230026P.R.China State Key Laboratory of Electroanalytical chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun130022P.R.China

Here we employ in-situ UV-Vis spectroscopy to monitor the sulfur redox reaction with oxygen-containing molecules as an additive,for example,biphenyl-4,4′-dicarboxylic acid(BDc).Furthermore,Raman spectrum,electron paramagnetic resonance(EPR),and electrospray ionization-mass spectrometry(ESI-MS)measurements reveal that the formation of BDc-S_(3)•^(‒)complexes can establish the long-term stability of polysulfide radicals,change the kinetics of sulfur redox reaction,and then generate decent capacity retention and rate *** to the density functional theory(DFT)analysis,S_(3)•^(‒)radicals are the underlying product of S_(6)^(2‒)cleavage,owing to the decreased chemical energy and the increased stability of S_(3)•^(‒)radicals through Lewis acid-base *** assembled Li-S batteries with BDc additive deliver a high reversible capacity of 420 mA·h·g^(−1)over 200 cycles with over 98%coulombic efficiency,under the current density of 0.2 c.

关键词： Radical Polysulfide In-situ UV-Vis Spectroscopy Electrolyte additive Lithium-sulfur battery

co-aromatization of methane and hexane over Pt encapsulated in ZSM-5 zeolite and the electronic effect of K promoters

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Science china chemistry 2024年第3期67卷 1017-1027页

作者： Bei Liu Fan Wang Xiaomeng dou Pengfei Li Hongwei Xiang yong yang Peng He State Key Laboratory of coal conversion Institute of Coal ChemistryChinese Academy of SciencesTaiyuan 030001China Department of chemistry Tsinghua UniversityBeijing 100084China National Energy R&D center for coal to Liquid Fuels Synfuels China Technology Co.Ltd.Beijing 101407China University of chinese Academy of Sciences Beijing 101408China Leibniz-Institut für Katalyse e.V.an der Universitat Rostock Rostock 18059Germany

The co-aromatization of methane with higher hydrocarbons represents a promising route to valorize methane, an abundant but underexploited carbon resource. In this study, we elucidate a novel approach to enhance the catalytic co-aromatization of hexane and methane by confining Pt within zeolite catalysts and modulating its electron density. Our findings show that encapsulating Pt within MFI structure is pivotal for activating the feedstock and fostering the formation of aromatic products. Interaction between K atoms and the silanol nest forms siloxy groups which are critical for the stabilization of Pt species. Tuning the K content in PtSn@MFI catalysts adeptly alters the electronic configuration of Pt clusters. This modification is corroborated by infrared and X-ray photoelectron spectroscopy analysis, and density functional theory calculations. Remarkably, the catalyst with 0.8 wt% K exhibits an optimal Pt electron density, driving its superior efficacy in the co-aromatization reaction, converting 0.78 mol of methane for each mole of hexane processed. By employing ~(13)c isotopic labeling and solid-state NMR studies, we demonstrate the participation of methane in the adsorbed species inside the zeolite channel and its incorporation to the benzyl site of the substitute group and phenyl rings in aromatic compounds, underscoring the importance of Pt encapsulation.

关键词： Pt encapsulation MFI zeolite methane activation co-aromatization ^(13)c solid-state NMR

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Novel c_(sf)/SiBcN composites prepared by densifying c_(sf)/MA-SiBcN with the PIP process:Oxidation behavior and damage mechanism

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Journal of Advanced ceramics 2024年第5期13卷 666-678页

作者： Wenhao dou Daxin Li Bingzhu Wang Zhihua yang Jun chen Dechang Jia Ralf Riedel yu Zhou Institute for Advanced ceramics School of Materials Science and EngineeringHarbin Institute of TechnologyHarbin 150001China Key Laboratory of Advanced Structural-Functional Integration Materials and Green Manufacturing Technology Harbin Institute of TechnologyHarbin 150001China chongqing Research Institute of HIT Chongqing 401135China Beijing Institute of control Engineering Beijing 100094China Institut für Materialwissenschaft Technische Universität DarmstadtDarmstadt D-64287Germany School of Materials Science and Engineering Harbin Institute of Technology(Shenzhen)Shenzhen 518055China

To improve the oxidation resistance of short carbon fiber(c_(sf))-reinforced mechanically alloyed SiBcN(MA-SiBcN)(c_(sf)/MA-SiBcN)composites,dense amorphous c_(sf)/SiBcN composites containing both MA-SiBcN and polymer-derived ceramics SiBcN(PDcs-SiBcN)were prepared by repeated polymer infiltration and pyrolysis(PIP)of layered c_(sf)/MA-SiBcN composites at 1100℃,and the oxidation behavior and damage mechanism of the as-prepared c_(sf)/SiBcN at 1300–1600℃ were compared and discussed with those of c_(sf)/*** c_(sf)/MA-SiBcN composites resist oxidation attack up to 1400℃ but fail at 1500℃ due to the collapse of the porous framework,while the PIP-densified c_(sf)/SiBcN composites are resistant to static air up to 1600℃.During oxidation,oxygen diffuses through preexisting pores and the pores left by oxidation of carbon fibers and pyrolytic carbon(Pyc)to the interior of the *** to the oxidative coupling effect of the MA-SiBcN and PDcs-SiBcN matrices,a relatively continuous and dense oxide layer is formed on the sample surface,and the interfacial region between the oxide layer and the matrix of the as-prepared composite contains an amorphous glassy structure mainly consisting of Si and O and an incompletely oxidized but partially crystallized matrix,which is primarily responsible for improving the oxidation resistance.

关键词： mechanically alloyed SiBcN(MA-SiBcN) polymer-derived ceramics SiBcN(PDcs-SiBcN) short carbon fiber-reinforced SiBcN(c_(sf)/SiBcN)composites polymer infiltration and pyrolysis(PIP) oxidation damage mechanism

Boosted Electrocatalytic Glucose Oxidation Reaction on Noble-Metal-Free MoO_(3)-Decorated carbon Nanotubes

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Transactions of Tianjin University 2024年第1期30卷 63-73页

作者： yu-Long Men Ning dou yiyi Zhao yan Huang Lei Zhang Peng Liu Department of chemical Engineering School of Chemistry and Chemical EngineeringShanghai Jiao Tong UniversityShanghai 200240China Department of Thyroid Breast and Vascular Surgery Shanghai Fourth People’s Hospital Affi liated to Tongji University School of MedicineShanghai 200081China Department of Vascular Surgery Changhai HospitalNaval Medical UniversityShanghai 200433China

Electrocatalytic glucose oxidation reaction(GOR)has attracted much attention owing to its crucial role in biofuel cell ***,we load MoO_(3)nanoparticles on carbon nanotubes(cNTs)and use a discharge process to prepare a noblemetal-free Mc-60 catalyst containing MoO_(3),Mo_(2)c,and a Mo_(2)c–MoO_(3)*** the GOR,Mc-60 shows activity as high as 745μA/(mmol/L cm^(2)),considerably higher than those of the Pt/cNT(270μA/(mmol/L cm^(2)))and Au/cNT catalysts(110μA/(mmol/L cm^(2))).In the GOR,the response minimum on Mc-60 is as low as 8μmol/L,with a steady-state response time of only 3 ***,Mc-60 has superior stability and anti-interference ability to impurities in the *** better performance of Mc-60 in the GOR is attributed to the abundant Mo sites bonding to c and O atoms at the MoO_(3)–Mo_(2)c *** Mo sites create active sites for promoting glucose adsorption and oxidation,enhancing Mc-60 performance in the ***,these results help to fabricate more effi cient noble-metal-free catalysts for the fabrication of glucose-based biofuel cells.

关键词： Interface eff ect Electrocatalysis Molybdenum oxide Glucose Oxidation reaction

Tunable VO_(2) cavity enables multispectral manipulation from visible to microwave frequencies

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Light(Science & Applications) 2024年第3期13卷 510-518页

作者： Hang Wei Jinxin Gu Tao Zhao Zhiyuan yan He-Xiu Xu Shuliang dou cheng-Wei Qiu yao Li center for composite Materials and Structure Harbin Institute of TechnologyHarbin 150001China National University of Singapore Department of Electrical&Computer EngineeringSingapore 117583Singapore School of chemical Engineering and Technology Harbin Institute of TechnologyHarbin 150001China Suzhou Laboratory Suzhou 215123China

Optical materials capable of dynamically manipulating electromagnetic waves are an emerging field in memories,optical modulators,and thermal ***,their multispectral design preliminarily attracts much attention,aiming to enhance their efficiency and integration of ***,the multispectral manipulation based on these materials is challenging due to their ubiquitous wavelength dependence restricting their capacity to narrow *** this article,we cascade multiple tunable optical cavities with selective-transparent layers,enabling a universal approach to overcoming wavelength dependence and establishing a multispectral platform with highly integrated *** on it,we demonstrate the multispectral(ranging from 400 nm to 3 cm),fast response speed(0.9 s),and reversible manipulation based on a typical phase change material,vanadium *** platform involves tandem VO_(2)-based Fabry–Pérot(F-P)cavities enabling the customization of optical responses at target bands *** can achieve broadband color-changing capacity in the visible region(a shift of~60 nm in resonant wavelength)and is capable of freely switching between three typical optical models(transmittance,reflectance,and absorptance)in the infrared to microwave regions with drastic amplitude tunability exceeding *** work represents a state-of-art advance in multispectral optics and material science,providing a critical approach for expanding the multispectral manipulation ability of optical systems.

关键词： spectral microwave visible

A comparison study on structure-function relationship of polysaccharides obtained from sea buckthorn berries using different methods:antioxidant and bile acid-binding capacity

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Food Science and Human Wellness 2024年第1期13卷 494-505页

作者： Qiaoyun Li Zuman dou Qingfei Duan chun chen Ruihai Liu yueming Jiang Bao yang Xiong Fu ScUT-Zhuhai Institute of Modern Industrial Innovation School of Food Science and EngineeringSouth China University of Technology381 Wushan RoadGuangzhou 510640China Guangzhou Institute of Modern Industrial Technology Nansha 511458China Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety Guangzhou 510640China Overseas Expertise Introduction center for Discipline Innovation of Food Nutrition and Human Health(111 center) Guangzhou 510640China Department of Food Science Stocking HallCornell UniversityIthaca 14853USA South china Botanical Garden Chinese Academy of SciencesGuangzhou 510650China

In this study,the structural characters,antioxidant activities and bile acid-binding ability of sea buckthorn polysaccharides(HRPs)obtained by the commonly used hot water(HRP-W),pressurized hot water(HRP-H),ultrasonic(HRP-U),acid(HRP-c)and alkali(HRP-A)assisted extraction methods were *** results demonstrated that extraction methods had significant effects on extraction yield,monosaccharide composition,molecular weight,particle size,triple-helical structure,and surface morphology of HRPs except for the major linkage *** analysis showed that HRP-U with filamentous reticular microstructure exhibited better thermal *** HRP-A with the lowest molecular weight and highest arabinose content possessed the best antioxidant ***,the rheological analysis indicated that HRPs with higher galacturonic acid content and molecular weight showed higher viscosity and stronger crosslinking network(HRP-c,HRP-W and HRP-U),which exhibited stronger bile acid binding *** present findings provide scientific evidence in the preparation technology of sea buckthorn polysaccharides with good antioxidant and bile acid binding capacity which are related to the structure affected by the extraction methods.

关键词： Sea buckthorn Extraction method Structure Rheological properties Antioxidant activity Bile acid binding capacity

Wave Attenuation and Turbulence Driven by Submerged Vegetation Under current-Wave Flow

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china Ocean Engineering 2024年第4期38卷 602-611页

作者： HUANG yu-ming Ding Lei WANG yi-fei cHEN Ben yANG Xiao-yu dou Xi-ping School of Water Resources and Hydropower Engineering Wuhan UniversityWuhan430072China Key Laboratory of Port Waterway and Sedimentation Engineering of MOTNanjing Hydraulic Research InstituteNanjing 210029China

A set of laboratory experiments are carried out to investigate the effect of following/opposing currents on wave *** vegetation canopies with aligned and staggered configurations were tested under the condition of various regular wave heights and current velocities,with the constant water depth being 0.60 m to create the desired submerged *** show that the vegetation-induced wave dissipation is enhanced with the increasing incident wave height.A larger velocity magnititude leads to a greater wave height attenuation for both following and opposing current ***,there is a strong positive linear correlation between the damping coefficientβand the relative wave height H_(0)/h,especially for pure wave *** the velocity profile,the distributions of U_(min)and U_(max)show different patterns under combined wave and *** time-averaged turbulent kinetic energy(TKE)vary little under pure wave and U_(c)=±0.05 m/s *** the increase of flow velocity amplitude,the time-averaged TKE shows a particularly pronounced increase trend at the top of the *** vegetation drag coefficients are obtained by a calibration *** empirical relations of drag coefficient with Reynolds and Keulegane-carpenter numbers are proposed to further understand the wave-current-vegetation interaction mechanism.

关键词： wave attenuation rigid vegetation following and opposing currents turbulent kinetic energy

Toward understanding the microstructure characteristics,phase selection and magnetic properties of laser additive manufactured Nd-Fe-B permanent magnets

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International Journal of Extreme Manufacturing 2024年第1期6卷 277-294页

作者： Bo yao Nan Kang Xiangyu Li dou Li Mohamed EL Mansori Jing chen Haiou yang Hua Tan Xin Lin State Key Laboratory of Solidiffcation Processing Northwestern Polytechnical UniversityXi’anShaanxi 710072People’s Republic of China Arts et Metiers Institute of Technology MSMPHESAM UniversitéF-51006 Chˆalons-en-ChampagneFrance Key Laboratory of Metal High Performance Additive Manufacturing and Innovative Design MIIT ChinaNorthwestern Polytechnical UniversityXi’anShaanxi 710072People’s Republic of China Texas A&M Engineering Experiment Station Institute for Manufacturing SystemsCollege StationTX 77843United States of America

Nd-Fe-B permanent magnets play a crucial role in energy conversion and electronic *** essential magnetic properties of Nd-Fe-B magnets,particularly coercivity and remanent magnetization,are significantly infuenced by the phase characteristics and *** this work,Nd-Fe-B magnets were manufactured using vacuum induction melting(VIM),laser directed energy deposition(LDED)and laser powder bed fusion(LPBF)*** evolution and phase selection of Nd-Fe-B magnets were then clarified in *** results indicated that the solidification velocity(V)and cooling rate(R)are key factors in the phase *** terms of the VIM-casting Nd-Fe-B magnet,a large volume fraction of theα-Fe soft magnetic phase(39.7 vol.%)and Nd2Fe17Bxmetastable phase(34.7 vol.%)areformed due to the low R(2.3×10-1?c s-1),whereas only a minor fraction of the Nd2Fe14B hard magnetic phase(5.15 vol.%)is *** the LDED-processed Nd-Fe-B deposit,although the Nd2Fe14B hard magnetic phase also had a low value(3.4 vol.%)as the values of V(c s-1)increased,part of theα-Fe soft magnetic phase(31.7vol.%)is suppressed,and a higher volume of Nd2Fe17Bxmetastable phases(47.5 vol.%)*** a result,both the VIM-casting and LDED-processed Nd-Fe-B deposits exhibited poor magnetic *** contrast,employing the high values of V(>10-2m s-1)and R(1.45×106?c s-1)in the LPBF process resulted in the substantial formation of the Nd2Fe14B hard magnetic phase(55.8 vol.%)directly from the liquid,while theα-Fe soft magnetic phase and Nd2Fe17Bxmetastable phase precipitation are suppressed in the LPBF-processed Nd-Fe-B ***,crystallographic texture analysis reveals that the LPBF-processedNd-Fe-B magnets exhibit isotropic magnetic ***,the LPBF-processed Nd-Fe-B deposit,exhibiting a coercivity of 656 k A m-1,remanence of 0.79 T and maximum energy product of 71.5 k J m-3,achieved an acceptable magnetic perfor

关键词： laser additive manufacturing(LAM) Nd-Fe-B permanent magnets numerical simulation microstructure magnetic properties