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A high-performance degradable Mg alloy suturing staple for single-arm oral stapling robot

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journal of Magnesium and Alloys 2024年第10期12卷 4096-4118页

作者： Q.H.Wang S.S.Liang F.S.yuan B.Y.Liu j.z.yu W.Wang N.Fakhar H.X.Li State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083China Center of Digital Dentistry Peking University Hospital of StomatologyBeijing 100081China College of Engineering Peking UniversityBeijing 100871China School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China Mechanical Engineering Department Hamedan University of TechnologyHamedanIran

Minimally invasive surgery(MIS)robots,such as single-arm stapling robots,are key to oral and maxillofacial surgery because they overcome space constraints in the oral cavity and deep ***,biodegradable suture staples should be developed for the single-arm stapling robots to avoid a secondary *** this aim,a new type of Mg-3zn-0.2Ca-2Ag biodegradable alloy wire was developed in this study applied as suture *** tensile strength,yield strength,and elongation are 326.1 MPa,314.5 MPa,and 19.6%,***,the alloy wire attains the highest yield strength value reported among all the biodegradable Mg wires,which is mainly attributed to fine grain strengthening and second phase strengthening such as Mg_(2)zn_(11) nano phase ***,the corrosion rate of this alloy wire in simulated body fluid(SBF)reaches 26.8 mm/y,the highest value among all the biodegradable Mg alloy wires reported so far,which is mainly from the intensified galvanic corrosion between the Ag17Mg54 phase and the Mg *** vitro studies demonstrate that the alloy wire exhibits good blood compatibility and low *** cone beam computed tomography(CBCT)data shows that the suture staple made of the Mg alloy wire provides better mechanical support in the early postoperative *** the single arm robot tests,it confirms that suture staples can close the wound tightly and remain stable over *** research provides a good material selection for the automated suturing in oral and throat surgery robots.

关键词： Biodegradable Mg alloy Suture staples Mechanical properties Micro-galvanic corrosion Biocompatibility.

Changes in source contributions to the oxidative potential of PM_(2.5)in urban Xiamen,China

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journal of Environmental Sciences 2025年第3期149卷 342-357页

作者： jia-Min Li Si-Min zhao Qi-yu Miao Shui-Ping Wu jie zhang james j.Schwab Fujian Provincial Key Laboratory for Coastal Ecology and Environmental Studies Xiamen UniversityXiamen 361102China Center for Marine Environmental Chemistry and Toxicology College of Environment and EcologyXiamen UniversityXiamen 361102China Atmospheric Sciences Research Center University at AlbanySUNYAlbany 12226USA

The toxicity of PM_(2.5)does not necessarily change synchronously with its mass *** this study,the chemical composition(carbonaceous species,water-soluble ions,and metals)and oxidative potential(dithiothreitol assay,DTT)of PM_(2.5)were investigated in 2017/2018 and 2022 in Xiamen,*** decrease rate of volume-normalized DTT(DTTv)(38%)was lower than that of PM_(2.5)(55%)between the two sampling ***,the mass-normalized DTT(DTTm)increased by 44%.Clear seasonal patterns with higher levels in winter were found for PM_(2.5),most chemical constituents and DTTv but not for *** large decrease in DTT activity(84%−92%)after the addition of EDTA suggested that watersoluble metals were the main contributors to DTT in *** increased gap between the reconstructed and measured DTTv and the stronger correlations between the reconstructed/measured DTT ratio and carbonaceous species in 2022were *** decrease rates of the hazard index(32.5%)and lifetime cancer risk(9.1%)differed from those of PM_(2.5)and DTTv due to their different main *** PMF-MLR model showed that the contributions(nmol/(min·m^(3)))of vehicle emission,coal+biomass burning,ship emission and secondary aerosol to DTTv in 2022 decreased by 63.0%,65.2%,66.5%,and 22.2%,respectively,compared to those in 2017/2018,which was consistent with the emission reduction of vehicle exhaust and coal consumption,the adoption of low-sulfur fuel oil used on board ships and the reduced production of ***,the contributions of dust+sea salt and industrial emission increased.

关键词： Chemical composition Oxidative potential Interannual change PMF-MLR Source apportionment

Exploratory growth and characterization of CaNdAl_(3)O_(7) single crystal with nonsymmetric structure in tetragonal family

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journal of Rare Earths 2025年第1期43卷 153-161,I0006页

作者： Xiangkang Peng Fapeng yu State Key Laboratory of Crystal Materials Institute of Crystal MaterialsShandong UniversityJinan250100China

The new component of melilite type crystal CaNdAl_(3)O_(7)(CNA)was grown by the Czochralski pulling *** crystal structure analysis was *** is found that the CNA crystal belongs to the tetragonal system with P-421m space *** cell parameters a=b=0.77461 nm and c=0.51089 *** density and Mohs hardness of CNA crystal are 4.08 g/cm^(3) and 5.45,*** specific heat of the crystal is 0.57-0.77 j/(g·K)in the temperature range of 30-300℃.X-ray photoelectron spectro scopy(XPS)shows that the crystal has stable atomic valence states and chemical *** vibration state of polyhedra groups in the crystal was measured by Raman spectra,and the piezoelectric response was analyzed based on the calculated results for the polyhedra polarization dipole *** relative dielectric permittivity of the CNA crystal at room temperature was determined to be 11.80 and the electrical resistivity was measured to be on the order of 5×10^(6)Ω·cm at 800℃.

关键词： Piezoelectric Melilite Crystal growth High-temperature Czochralski Rareearths

Conversion-type cathode materials for high energy density solid-state lithium batteries

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journal of Energy Chemistry 2025年第1期100卷 409-425页

作者： yuhao Ma Shihong Qing Hongyu Liu Chuntao Ma yuan yu Chuang yu Liping Wang School of Materials and Energy University of Electronic Science and Technology of ChinaChengdu 611731SichuanChina zhejiang Provincial Key Laboratory of Fiber Materials and Manufacturing Technology Zhejiang Sci-Tech UniversityHangzhou 310018ZhejiangChina State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074HubeiChina

Solid-state lithium batteries(SSLBs)are regarded as an essential growth path in energy storage systems due to their excellent safety and high energy *** particular,SSLBs using conversion-type cathode materials have received widespread attention because of their high theoretical energy densities,low cost,and *** the great progress in research and development of SSLBs based on conversiontype cathodes,their practical applications still face challenges such as blocked ionic-electronic migration pathways,huge volume change,interfacial incompatibility,and expensive processing *** review focuses on the advantages and critical issues of coupling conversion-type cathodes with solid-state electrolytes(SSEs),as well as state-of-the-art progress in various promising cathodes(e.g.,FeS_(2),CuS,FeF_(3),FeF_(2),and S)in ***,representative research on conversion-type solid-state full cells is discussed to offer enlightenment for their practical ***,the energy density exhibited by the S cathode stands out impressively,while sulfide SSEs and halide SSEs have demonstrated immense potential for coupling with conversion-type ***,perspectives on conversion-type cathodes are provided at the material,interface,composite electrode,and battery levels,with a view to accelerating the development of conversion-type cathodes for high-energy–density SSLBs.

关键词： Conversion-type cathode Lithium-free cathode Solid-state electrolyte Solid-state lithium battery High energy density

Upper Bounds on the Multicolor Ramsey Numbers r_(k)(C_(4))

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Acta Mathematicae Applicatae Sinica 2025年第1期41卷 286-294页

作者： Tian-yu LI Qi-zhong LIN Center for Discrete Mathematics Fuzhou UniversityFuzhou 350108China

The multicolor Ramsey number r_(k)(C_(4))is the smallest integer N such that any k-edge coloring of KN contains a monochromatic C_(4).The current best upper bound of r_(k)(C_(4))was obtained by Chung(1974)and independently by Irving(1974),i.e.,r_(k)(C_(4))≤k^(2)+k+1 for all k≥*** is no progress on the upper bound since *** this paper,we improve the upper bound of r_(k)(C_(4))by showing that r_(k)(C_(4))≤k^(2)+k-1 for even k≥*** improvement is based on the upper bound of the Turan number ex(n,C4),in which we mainly use the double counting method and many novel ideas from Firke,Kosek,Nash,and Williford[***,Ser.B 103(2013),327-336].

关键词： Multicolor Ramsey number Turan number 4-cycle

Revisit the Gibbs-Thomson Equation Fitting of Poly(butylene succinate) Based on Oligomer Extended-Chain Crystals

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CHINESE jOURNAL OF POLYMER SCIENCE 2025年第2期43卷 392-398页

作者： Li, Na Tian, yu-Pei Wu, Tian-yu zhou, Qiong Ye, Hai-Mu China Univ Petr Coll New Energy & Mat Beijing 102249 Peoples R China

The equilibrium melting point (Tm0) is a crucial thermodynamic parameter for characterizing the crystallization and melting behavior of semi-crystalline polymers. However, the direct measurement of Tm0 poses a significant challenge because of the difficulty in physically fabricating fully-extended chain crystals of high-molecular-weight polymers. Therefore, various extrapolation equations for Tm0 have been proposed that utilize the thermal properties of ordinary folded-chain lamellae. Among these, the Gibbs-Thomson equation is one of the most commonly employed for modeling. Despite its widespread use, there are notable variations in the Tm0 values obtained by different research groups, even when based on similar samples. This raises questions about the validity and accuracy of using the Gibbs-Thomson equation to linearly extrapolate Tm0. In this study, we prepared a series of oligomer extended-chain crystals (ECCs) of poly(butylene succinate) (PBS) and used their properties for Gibbs-Thomson fitting. The results reveal a perfect linear relationship, with an extrapolated Tm0 value of 136.08 degrees C. The basal surface free energy of the oligomer ECCs was calculated as 0.084 j/m2, which is approximately twice that of folded-chain lamellae. This difference is attributed to the aggregation of highly mobile free tails on the crystal surface. The two structural features of oligomer ECCs-large thickness and fixed surface-better fulfill the conditions for applying the Gibbs-Thomson equation, ensuring its validity and accuracy. Therefore, we believe that the Gibbs-Thomson fit can produce reliable results when sufficient high-quality data are used.

关键词： Equilibrium melting point Extended-chain crystal Gibbs-Thomson equation Inclusion complex

Nitrogen-cycling processes under long-term compound heavy metal(loids)pressure around a gold mine:Stimulation of nitrite reduction

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journal of Environmental Sciences 2025年第1期147卷 571-581页

作者： Xuesong Hu Xiaoxia Liu Shuo zhang Caihong yu School of Chemical&Environmental Engineering China University of Mining and Technology(Beijing)Beijing 100083China Beijing Cultivated Land Construction and Protection Center Beijing 100020China

Mining and tailings deposition can cause serious heavy metal(loids)pollution to the surrounding soil *** microorganisms adapt their metabolism to such conditions,driving alterations in soil *** study aims to elucidate the response patterns of nitrogen-cycling microorganisms under long-term heavy metal(loids)*** results showed that the diversity and abundance of nitrogen-cyclingmicroorganisms showed negative feedback to heavy metal(loids)*** microorganisms were shown to be the dominant microorganisms with over 60%of relative abundance and a complex community structure including 27 ***,the key bacterial species in the denitrification process were calculated using a random forest model,where the top three key species(Pseudomonas stutzei,Sphingobium japonicum and Leifsonia rubra)were found to play a prominent role in nitrite *** gene analysis and qPCR revealed that nirK,which is involved in nitrite reduction,significantly accumulated in the most metal-rich soil with the increase of absolute abundance of 63.86%.The experimental results confirmed that the activity of nitrite reductase(Nir)encoded by nirK in the soil was increased at high concentrations of heavy metal(loids).Partial least squares-path model identified three potential modes of nitrite reduction processes being stimulated by heavy metal(loids),the most prominent of which contributed to enhanced nirK abundance and soil Nir activity through positive stimulation of key *** results provide new insights and preliminary evidence on the stimulation of nitrite reduction processes by heavy metal(loids).

关键词： N cycle Nitrite reduction Nitrite reductase Metagenome Key species

Hyperbranched Poly(α-aminonitrile)s Constructed via Catalyst-Free Multicomponent Polymerization of Trialdehydes, Diamines and Trimethylsilyl Cyanide

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CHINESE jOURNAL OF POLYMER SCIENCE 2025年第2期43卷 341-349页

作者： Cheng, Tian-yu Ding, jian-Qing Tong, yu-Xin Fang, jun-Guo Wang, jia Anhui Polytech Univ Sch Chem & Environm Engn Wuhu 241000 Peoples R China Songshan Lake Mat Lab Dongguan 523808 Peoples R China

Functional hyperbranched polymers, as an important class of materials, are widely applied in diverse areas. Therefore, the development of simple and efficient reactions to prepare hyperbranched polymers is of great significance. In this work, trialdehydes, diamines, and trimethylsilyl cyanide could easily undergo multicomponent polymerization under mild conditions, producing hyperbranched poly(alpha-aminonitrile)s with high molecular weights (Mw up to 4.87x104) in good yields (up to 85%). The hyperbranched poly(alpha-aminonitrile)s have good solubility in commonly used organic solvents, high thermal stability as well as morphological stability. Furthermore, due to the numerous aldehyde groups in their branched chains, these hb-poly(alpha-aminonitrile)s can undergo one-pot, two-step, four-component post-polymerization with high efficiency. This work not only confirms the efficiency of our established catalyst-free multicomponent polymerization of aldehydes, amines and trimethylsilyl cyanide, but also provides a versatile and powerful platform for the preparation of functional hyperbranched polymeric materials.

关键词： Catalyst-free Multicomponent polymerization Hyperbranched polymer Post-polymerization

Microstructural evolution during tempering process and mechanical properties of Cr-Ni-Mo-V/Nb high strength steel

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journal of Iron and Steel Research International 2025年第1期32卷 270-281页

作者： zi-wei Lv jing Fan Rui Wang zhi-qiang yu Yan Kang Yong Hu Lei-feng Tuo jürgen Eckert zhi-jie Yan School of Materials Science and Engineering North University of ChinaTaiyuan 030051ShanxiChina Shanxi Key Laboratory of Advanced Metal Materials for Special Environments North University of ChinaTaiyuan 030051ShanxiChina School of Materials Science and Engineering Taiyuan University of Science and TechnologyTaiyuan 030024ShanxiChina Erich Schmid Institute of Materials Science Austrian Academy of SciencesLeoben 8700Austria Department of Materials Science Chair of Materials PhysicsMontanuniversitat LeobenLeoben 8700Austria

High strength steels exhibit superior mechanical properties due to the unique microstructure,which successfully solves the drawback of the inevitable strength-toughness trade-off that occurs in traditional *** we investigated the effect of matrix and precipitates on mechanical properties of Cr-Ni-Mo-V/Nb steel after water quenching and tempering(150-500℃).The results showed that the microstructure of the present steel is noticeably tuned by changing the tempering *** excellent combination of strength(a yield strength of 1308 MPa with a total elongation of 8.2%)and toughness(Charpy V-notch impact toughness of 40.5 j/cm^(2))is obtained upon tempering at 200℃.This is attributed to the lath martensite containing high dislocation density,the martensite-twin substructure,and the strengthening effects of the precipitated needle-likeε-carbides and spherical VC *** acicularε-carbides are replaced by the rod-shaped Fe_(3)C at the tempering temperature of 350℃,resulting in the remarkable deterioration in strength,hardness,and *** carbides formed at a tempering temperature of 500℃ are beneficial to the enhancement of the elongation and toughness,but the strength decreases due to the matrix softening caused by the recovery of dislocation.

关键词： High strength steel Tempering Microstructure Carbide Mechanical property