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Single-atom Ni-N_(4) for enhanced electrochemical sensing

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Nano Research 2024年第8期17卷 7658-7664页

作者： zhuhui Qin Bo Tang Guiru zhang chongqing zhu Kun Jiang Bowei zhang Fu-Zhen Xuan Shanghai Key Laboratory of Intelligent Sensing and Detection Technology East China University of Science and TechnologyShanghai 200237China Key Laboratory of Pressure Systems and Safety of Ministry of Education East China University of Science and TechnologyShanghai 200237China School of Mechanical and Power engineering East China University of Science and TechnologyShanghai 200237China Key Laboratory of Theoretical and Computational Photochemistry Ministry of EducationCollege of ChemistryBeijing Normal UniversityBeijing 100875China Interdisciplinary Research Center School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China

Single-atom catalysts(SACs)attract widespread attention in heterogeneous catalysis due to their maximum atomic utilization efficiency and unique physical and chemical ***,their applications in chemical sensing keep huge potential but remain ***,a Ni-N_(4)-C SAC was synthesized for the trace detection of dopamine(DA)and uric acid(UA).The Ni-N_(4)-C SAC exhibited superior sensing performance compared to the Ni *** detection range for DA and UA were 0.05–75μM and 5–90μM with detection limits of 0.027 and 0.82μM,*** functional theory(DFT)computations indicate that Ni-N_(4)-C has a lower reaction barrier during electrochemical process,indicating that the atomic Ni sites possess higher intrinsic activity than Ni ***,DA and UA show strong potential dependency on the Ni-N_(4)-C catalyst,indicating its applicability for their concurrent *** work extends the application of SACs in chemical sensing.

关键词： single-atom catalysts chemical sensing dopamine uric acid

Effects of scandium addition on microstructure and mechanical properties of ZK60 alloy

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Progress in Natural science:materials International 2011年第1期21卷 59-65页

作者： Fu-sheng PAN~(1,2),Ting-ting LIU~(1,2),Xi-yan zhang~(1,2),Ai-tao TANG~(1,2),Wei-qing WANG~(1,2) 1.National engineering Research Center for Magnesium Alloys,chongqing university,chongqing 400045,china 2.college of materials science and engineering,chongqing university,chongqing 400045,china [a] National engineering Research Center for Magnesium Alloys Chongqing University Chongqing 400045 China [b] college of materials science and engineering Chongqing University Chongqing 400045 China

The effects of Sc addition on the microstructure and mechanical properties of the ZK60 wrought magnesium alloy were investigated by using optical microscope,scanning electron microscopy,X-ray diffraction and tensile *** experimental results show that a minor Sc addition to ZK60 alloy has an obvious effect on the refinement of the microstructure of the ZK60 alloy. During hot extrusion,incomplete dynamic recrystallization occurs in all the alloys,and the recrystallized grains become much finer with increasing Sc *** tensile strengths of ZK60 evidently increase with the addition of Sc,but the elongations decrease. The ZK60 alloy with 0.6%(mass fraction) Sc addition is found to have the tensile strength of about 350 MPa and the yield strength of about 280 *** T6 heat treatment,the tensile strength of the alloy containing 0.6%Sc remains almost ***, the yield strength of the alloy increases up to 352 MPa,and the ratio of the tensile strength to the yield strength is close to 1.

关键词： wrought magnesium alloy scandium microstructure mechanical properties

Thermal-stress Simulation of Direct-chill Casting of AZ31 Magnesium Alloy Billets

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Journal of Wuhan university of Technology(materials science) 2009年第3期24卷 376-382页

作者：胡红军 college of materials science and engineering Chongqing University National engineering Research Center for Magnesium Alloys Chongqing University college of Material science and engineering Chongqing University of Technology

Two-dimensional （2D） transient coupled finite element model was developed to compute the temperature and stress field in cast billets, so as to predict the defects of the I-type billets made from AZ31 magnesium alloy and find the causes and solutions for surface cracks and shrinkages during direct-chill （DC） casting process. Method of equivalent specific heat was used in the heat conduction equation. The boundary and initial conditions used for primary and secondary cooling were elucidated on the basis of the heat transfer during the solidification of the billet. The temperature and the thermal-stress fields were simulated with the thermal-structural coupled module of ANSYS software. The influences of casting parameters on the distributions of temperature and stress were studied, which helped optimize the parameters （at pouring temperature of 680 ℃, casting speed of 2 min/s, heat-transfer coefficient of the second cooling equals to 5 000 W/m^2.℃^-1）. The simulation results of thermal stress and strain fields reveal the formation mechanism of some casting defects, which is favourable for optimizing the casting parameters and obtain high quality billets. Some measures of controlling processes were taken to prevent the defects for direct-chill casting billets.

关键词： magnesium alloy direct-chill casting temperature and stress fields numerical simulation solidification model

Grain refinement of Mg-Li-Al cast alloys by adding typical master alloys

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Progress in Natural science:materials International 2011年第3期21卷 236-239页

作者： Bin JIANG~(1,2),Qing-shan YANG~2,Ming-xing zhang~3,Dong QIU~3,Rui-hong LI~2,Fu-sheng PAN~(1,2) 1.National engineering Research Center for Magnesium Alloys,chongqing university,chongqing 400044,china 2.college of materials science and engineering,chongqing university,chongqing 400044,china 3.Division of materials,School of Mechanical and Mining engineering, The university of Queensland,St Lucia,QLD 4072,Australia [a] National engineering Research Center for Magnesium Alloys Chongqing University Chongqing 400044 China [b] college of materials science and engineering Chongqing University Chongqing 400044 China [c] Division of materials School of Mechanical and Mining Engineering The University of Queensland St Lucia QLD 4072 Australia

Commercial Al-3Ti-1C and Al-5Ti-1B master alloys were added in order to refine the grains of Mg-Li-Al *** effects of their addition levels on grain refinement of Mg-Li-Al cast alloy were investigated and the mechanism of the grain refinement was *** results showed that the addition of Al-3Ti-1C master alloy reduced the grain size of LA141 cast alloy from 900μm to 400μm,while the addition of Al-5Ti-1B master alloy reduced the grain size of LA51 cast alloy from 500μm to 240μ*** grain refining mechanism was the heterogeneity nucleation of TiC and TiB2,because of less than 10%mismatches of TiC/β-Li and TiB2/α-Mg.

关键词： magnesium lithium alloy master alloy grain refinement

Surface Nanocrystallization of Magnesium Alloy AZ91D by High-Energy Shot Peening

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Journal of Wuhan university of Technology(materials science) 2009年第4期24卷 515-519页

作者：张津 School of materials science & engineering University of Science and Technology Beijing college of materials science & engineering Chongqing University of Technology

High-energy shot peening （HESP）, a method to produce severe plastic deformation by high velocity flying balls, was applied on die cast magnesium alloy AZ91D. Effects of surface nanocrystallization by HESP and heat treatment at different temperatures were investigated. The mi- crostructure evolution was conducted using X-ray diffraction （XRD） and field emission scanning electronic microscopy （FESEM）. The hardness was measured by microhardness tester. The experimental results show that surface nanocrystrallization of AZ91D obtained by HESP would lead to the increase of microhardness. Low temperature heated at 100℃ for 1 h do not change the property obviously. However, both the microstructure and microhardness vary greatly after heat treatment at 400℃ for 1 h.

关键词： AZ91 D surface nanocrystallization HESP microhardnss corrosion resistance

Solid reaction mechanism of CaHPO_4·2H_2O + CaCO_3 with and without yttria

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Rare Metals 2009年第1期28卷 77-81页

作者： WANG Yong GAO Jiacheng HU Jinzhu zhang Yan college of materials science and engineering Chongqing University Chongqing 400045 China National engineering Research Center for Magnesium Alloys Chongqing University Chongqing 400045 China college of materials science and engineering Southwest University Chongqing 400700 China

The effect of yttria on the solid reaction mechanism of a CaHPO4·2H2O ＋ CaCO3 system at different temperatures was experimentally stud-ied. The samples with and without yttria were subjected to thermogravimetric/differential scanning calorimetry measurement. The samples were heat treated at the temperatures corresponding to the peaks on the DSC spectra, and the resulted phase compositions were identified by X-ray diffraction. The transformation mechanism was deduced by comparing the phases obtained at different temperatures. The results show that the transformations at below 1073 K are not affected by yttria, but all those at above 1073 K are completely altered. The formation tem-perature of hydroxyapatite decreases by 134 K, and the decomposition temperature increases by 38 K. The polymorphous transformation of Ca3（PO4）2 from β phase to α phase increases by 47 K. The thermodynamic properties of the transformations at above 1073 K are also modi-fied by the addition of yttria; that is, the endothermal peaks are substituted by exothermal peaks.

关键词： bioceramics solid reaction mechanism X-ray diffraction thermal analysis yttria

Sequence-activated chemiluminescence probes: programmable illumination for high-contrast in vivo sensing and imaging

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science china Chemistry 2024年

作者： yutao zhang Juan Li Weihong zhu Zhiqian Guo Shanghai Key Laboratory of Functional materials Chemistry Joint International Research Laboratory of Precision Chemistry and Molecular Engineering Institute of Fine Chemicals School of Chemistry and Molecular Engineering East China University of Science and Technology State Key Laboratory of Bioreactor engineering Shanghai Frontier Science Research Base of Optogenetic Techniques for Cell MetabolismEast China University of Science & Technology

Sequence-activated chemiluminescence(CL) technique offers a unique approach to detecting specific biomolecules or cellular events with high sensitivity and spatial resolution. The fundamental principle behind sequence-activated CL probes involves tailoring highly-controllable CL signals in response to specific sequences or events of interest, thus enabling high-contrast signals under complex physiological conditions. This sequential activation could be triggered by enzymes, reactive oxygen species(ROS), biothiols or changes in the microenvironment. These unique sequence-activated CL probes bestow several advantages, including minimal background, deep-tissue penetration, and the ability of non-invasive or minimally invasive detection. The sequence-activated CL techniques represent a significant advancement in molecular imaging and diagnostics. In this mini-review, we focus on the latest developments in sequential CL probes, addressing the technical challenges and discussing the future trajectory by harnessing CL signaling and molecular recognition.

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Melt Synthesis and Characterization of Poly(L-lactic Acid) Chain Linked by Multifunctional Epoxy Compound

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Journal of Wuhan university of Technology(materials science) 2010年第5期25卷 774-779页

作者：王远亮 Research Center of Bioinspired materials science and engineering Bioengineering College Chongqing University

High molecular weight（Mw） poly（L-lactic acid）s（PLLAs） were synthesized using multifunctional epoxy compound（Joncryl-ADR4370） as chain extender. The products were characterized by gel permeation chromatography（GPC） and spectroscopy（1HNMR and FTIR）. The results indicated that the Mw of PLLA increased with the increasing of the ratio of epoxy compound and the extending of reaction time. The highest Mw of PLLA reached 360 000 g/mol when the ratio of epoxy compound was 1.5 wt%. However, the reactants turned to cross-linking when the ratio of epoxy compound was over 1.5 wt%. Differential scanning calorimetry（DSC） measurements demonstrated that the glass transition（Tg） and melting temperatures（Tm） of products increased slightly as the increase of the molecular weight. Analysis of the hydrolytic degradation in vitro showed that the branched PLLA possessed the quicker degradability than that of the linear PLLA.

关键词： melt synthesis poly(lactic acid) epoxy compound chain extender

Comparative Analysis on Microstructure and Mechanical Properties between EBW and TANDEM Welding of 7A52 Aluminum Alloy Joint

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稀有金属材料与工程 2011年第S4期40卷 68-73页

作者： Zhai Xiwei1,2,Chen Furong1,2,Bi Liangyan1,2,zhang Chuanchen3 1college of materials science and engineering,Inner Mongolia university of Technology,Hohhot 010051,china2Key Laboratory of materials Processing & Control engineering of Inner Mongolia Autonomous Region,Hohhot 010051,china3School of materials science and engineering,university of science and Technology Beijing,Beijing 100083,china Inner Mongolia Univ Technol Coll Mat Sci & Engn Hohhot 010051 Peoples R China Key Lab Mat Proc & Control Engn Inner Mongolia Au Hohhot 010051 Peoples R China Univ Sci & Technol Beijing Sch Mat Sci & Engn Beijing 100083 Peoples R China

The plates with 20mm thickness of 7A52 aluminum alloy were welded by electron beam welding and TANDEM welding with ER5356 filler,*** microstructure and mechanical properties of the joints were *** results showed that the microstructure of EBW metal was finer and tighter than TANDEM *** heat-affected zone of the EBW joint was narrower,its hardness was higher and the tensile strength improved obviously compared to TANDEM *** quality control of the EBW joint was made without abnormal porosity,inclusions and ***,the EBW joint of 7A52 aluminum alloy showed excellent performance.

关键词： 7A52 aluminum alloy electron beam welding TANDEM welding microstructure mechanical properties