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Effect of elevated-temperature annealing on microstructure and properties of Cu−0.15Zr alloy

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Transactions of Nonferrous Metals Society of China 2021年第12期31卷 3772-3784页

作者： Zi-chen ZHANG ri-chu wang Chao-qun PENG Yan FENG Xiao-feng wang Xiang WU Zhi-yong CAI School of Materials Science and Engineering Central South UniversityChangsha 410083China Hunan Province Key Laboratory of Electronic Packaging and Advanced Functional Materials Central South UniversityChangsha 410083China College of Materials Science and Engineering Changsha University of Science and TechnologyChangsha 410114China

Cu−0.15Zr(wt.%)alloy with uniform and fine microstructure was fabricated by rapid solidification followed by hot *** of microstructure,mechanical properties and electrical conductivity of the alloy during elevated-temperature annealing were *** alloy exhibits good thermal stability,and its strength decreases slightly even after annealing at 700℃ for 2 *** nano-sized Cu_(5)Zr precipitates show significant pinning effect on dislocation moving,which is the main reason for the high strength of the ***,the large-size Cu_(5)Zr precipitates play a major role in retarding grain growth by pinning the grain boundaries during *** annealing at 700℃ for 2 h,the electrical conductivity of samples reaches the peak value of 88%(IACS),which is attributed to the decrease of vacancy defects,dislocations,grain boundaries and Zr solutes.

关键词： Cu−Zr alloy rapid solidification annealing microstructure tensile strength electrical conductivity

Single-atom Co alloyed Ru for electrocatalytic nitrite reduction to ammonia

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Nano Research 2024年第5期17卷 3660-3666页

作者： Fuzhou wang Jiaqi Xiang Guike Zhang Kai Chen Ke chu School of Materials Science and Engineering Lanzhou Jiaotong UniversityLanzhou 730070China

Electrochemical converting NO_(2)^(-)into NH_(3)(NO_(2)RR)holds an enormous prospect to attain efficient NH_(3) electrosynthesis and polluted NO_(2)^(-)***,we report single-atom Co alloyed Ru(Co_(1)Ru)as an efficient and durable NO_(2)RR *** experimental and theoretical investigations reveal that single-atom Co alloying of Ru enables the construction of Co_(1)-Ru heteronuclear active sites to synergistically promote NO_(2)^(-)activation/hydrogenation while suppressing the competitive H_(2) evolution,rendering the greatly enhanced activity and selectivity of Co_(1)Ru towards the NO_(2)***,Co_(1)Ru assembled within a flow cell exhibits an impressive NH_(3) yield rate of 2379.2μmol·h^(-1)·cm^(-2) with an NH_(3)-Faradaic efficiency of 92%at a high current density of 415.9 mA·cm^(-2),which is among the highest NO_(2)RR performances reported to date.

关键词： electrochemical converting NO_(2)-into NH3 single-atom alloys theoretical computations industrial-level current density

ED-Ged:Nighttime Image Semantic Segmentation Based on Enhanced Detail and Bidirectional Guidance

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Computers, Materials & Continua 2024年第8期80卷 2443-2462页

作者： Xiaoli Yuan Jianxun Zhang Xuejie wang Zhuhong chu College of Computer Science and Engineering Chongqing University of TechnologyChongqing400054China

Semantic segmentation of driving scene images is crucial for autonomous *** deep learning technology has significantly improved daytime image semantic segmentation,nighttime images pose challenges due to factors like poor lighting and overexposure,making it difficult to recognize small *** address this,we propose an Image Adaptive Enhancement(IAEN)module comprising a parameter predictor(Edip),multiple image processing filters(Mdif),and a Detail Processing Module(DPM).Edip combines image processing filters to predict parameters like exposure and hue,optimizing image *** adopt a novel image encoder to enhance parameter prediction accuracy by enabling Edip to handle features at different *** strengthens overlooked image details,extending the IAEN module’s *** the segmentation network,we integrate a Depth Guided Filter(DGF)to refine segmentation *** entire network is trained end-to-end,with segmentation results guiding parameter prediction optimization,promoting self-learning and network *** lightweight and efficient network architecture is particularly suitable for addressing challenges in nighttime image *** experiments validate significant performance improvements of our approach on the ACDC-night and Nightcity datasets.

关键词： Night driving semantic segmentation nighttime image processing adverse illumination differentiable filters

Synthesis and sintering of beryllium oxide nanoparticles

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Progress in Natural Science:Materials International 2010年第1期20卷 81-86页

作者： Xiao-feng wang,ri-chu wang,Chao-qun PENG,Ting-ting LI,Bing LIU School of Materials Science and Engineering,Central South University,Changsha 410083,China School of Materials Science and Engineering Central South University Changsha 410083 China

BeO nanoparticles were prepared by polyacrylamide gel route and the sintering properties of synthesized powder as a function of sintering temperature and time were *** behaviors of the polyacrylamide gel and beryllium salt were studied by thermogravimetry analysis(TGA).The calcination temperature(690℃)of the beryllium sulfate covered in polyacrylamide xerogel was almost 150℃lower than that obtained by traditional *** nanocrystallites of the BeO particles were estimated by X-ray diffraction(XRD)according to Debye-Scherrer *** electron microscopy(TEM) investigation revealed that the average particle size of the BeO nanoparticles prepared by calcining at 800℃for 2 h,ranges from 15 nm to 25 *** sintering temperature was down to 1600℃,which was around 200℃lower than conventional sintering temperature of the compact sample with common *** densification rate was fast at the first 3 *** thermal conductivity of the sample sintered at 1600℃for 6 h was 186.6 W/(m·K).

关键词： BeO nanoparticles polyacrylamide gel sintering thermal conductivity

Performance of water-coupled charge blasting under different in-situ stresses

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Journal of Central South University 2024年第7期31卷 2300-2320页

作者： ZHOU Zi-long wang Zhen CHENG Rui-shan CAI Xin LAN ri-yan School of Resources and Safety Engineering Central South UniversityChangsha 410083China Center for Infrastructural Monitoring and Protection School of Civil and Mechanical EngineeringCurtin UniversityBentleyAustralia Guangxi Xinfazhan Communication Group Co. Ltd.Nanning 530000China

Water-coupled charge blasting is a promising technique to efficiently break rock *** this study,numerical models of double boreholes with water-coupled charge are established using LS-DYNA and are calibrated by the tests of rock masses subjected to explosion loads to examine its *** crack levels of rock mass induced by water-coupled charge blasting and air-coupled charge blasting are first *** is found that water-coupled charge blasting is more appropriate to fracture deep rock mass than air-coupled charge *** addition,the effects of rock properties,water-coupled charge coefficients,and borehole connection angles on the performance of water-coupled charge blasting are *** results show that rock properties and water-coupled charge coefficients can greatly influence the crack and fragmentation levels of rock mass induced by water-coupled charge blasting under uniform and non-uniform in-situ ***,changing borehole-connection angles can only affect crack and fragmentation levels of rock mass under non-uniform in-situ stresses but barely affect those under uniform in-situ stresses.A formula is finally proposed by considering the above-mentioned factors to provide the design suggestion of water-coupled charge blasting to fracture rock mass with different in-situ stresses.

关键词： water-coupled blasting in-situ stress water-coupled charge coefficient rock type borehole-connection angle

S1-supported Pd@CeO_(2) quasi-core@shell materials as advanced catalysts for selective hydrogenation of furfural

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Chinese Chemical Letters 2024年第3期35卷 493-496页

作者： Xiang chu Lingling Zhang Ke wang Rui Zhang Xiao wang Shuyan Song Hongjie Zhang State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China School of Applied Chemistry and Engineering University of Science and Technology of ChinaHefei 230026China

Bare Pd metal nanoparticles invariably suffer from poor selectivity in furfural hydrogenation by forming flat configurations,with the aromatic ring of the substrate molecules parallel to the metal ***,we put forward a promising solution by using CeO_(2)as promoters to modify Pd nanoparticles for modulating the adsorption behaviors of furfural *** achieve the highly-desired ultra-small Pd@CeO_(2)core@shell nanostructure,a“constrained auto-redox”synthesis is developed,in which silicalite-1 supports play the key role of providing their surface as the landing place of PdO_(x)precursors for inhibiting the overgrowth and the *** the best of our knowledge,this is one of the smallest core@shell materials obtained from aqueous *** evaluated as catalysts,Pd@CeO_(2)/S-1 gives 98.9%conversion of furfural with 94.3%selectivity for furfural alcohol in 15 h,which is much better than that of Pd/S-1(88.6%conversion with 44.3%selectively).The DFT simulation reveals a strong interaction between the defects of CeO_(2)and the oxygen atom of the–CHO group in furfural molecules,which benefits the selective hydrogenation occurred in the–CHO group rather than the furan ring.

关键词： Core@shell Palladium Ceria Auto-redox synthesis Hydrogenation

电子封装用Al-Si功能梯度材料的显微组织和性能

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Transactions of Nonferrous Metals Society of China 2023年第12期33卷 3583-3596页

作者：周玮王日初彭超群蔡志勇中南大学材料科学与工程学院长沙410083 中南大学电子封装与先进功能材料重点实验室长沙410083

通过喷雾沉积法制备用于电子封装的双层和三层Al-Si功能梯度材料。结果表明,梯度材料具有致密的显微组织和良好的层间结合。三层梯度材料的抗弯强度高于双层梯度材料,以高Si含量层为承载面的H-L方向的抗弯强度高于以低Si含量层为承载面... 详细信息

通过喷雾沉积法制备用于电子封装的双层和三层Al-Si功能梯度材料。结果表明,梯度材料具有致密的显微组织和良好的层间结合。三层梯度材料的抗弯强度高于双层梯度材料,以高Si含量层为承载面的H-L方向的抗弯强度高于以低Si含量层为承载面的L-H方向。所有梯度材料的导热系数均超过140W/(m·K),且其热膨胀系数没有明显的差异。经热冲击处理后,双层梯度材料出现的裂纹比三层梯度材料更多更大,这是由于界面上的高热应力和大尺寸Si颗粒因应力集中而趋于破裂。

关键词：电子封装功能梯度材料 Al-Si合金有限元分析抗热震性能

Improvement of deformation capacity of gas-atomized hypereutectic Al-Si alloy powder by annealing treatment

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Transactions of Nonferrous Metals Society of China 2018年第8期28卷 1475-1483页

作者： Zhi-yong CAI chun ZHANG ri-chu wang Chao-qun PENG Xiang WU Hai-pu LI Ming YANG School of Chemistry and Chemical Engineering Central South UniversityChangsha 410083China School of Materials Science and Engineering Central South UniversityChangsha 410083China

Gas-atomized pure metal or alloy powders are widely used as raw material in the preparation of high performance materials by powder metallurgy route（compaction and sintering）. However, cold compactibility of gas-atomized Al-Si alloy powder is inhibited due to the high strength as a result of the refined Si phases and the supersaturated Al matrix. The effect of annealing on improving the compactibility of Al-Si alloy powder was studied. The densification was investigated by the HECKEL compaction equation in terms of deformation capacity. Moreover, the microstructures and bending fracture surfaces of the green compacts were examined to clarify the densification behavior. The results show that a maximum relative density of 96.1% is obtained when the powder is annealed at 400 °C. The deformation capacity is significantly improved by annealing treatment due to the softening of Al matrix, precipitation of supersaturated Si phases, dissolution of needle-like eutectic phase, and spheroidization of Si phases.

关键词： powder compaction gas atomization Al-Si alloy, annealing microstructure

Metagenomic Insight Reveals the Microbial Structure and Function of the Full-Scale Coking Wastewater Treatment System:Gene-Based Nitrogen Removal

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Engineering 2024年第5期36卷 76-89页

作者： Jiaying Ma Fan wang Haifeng Fan Enchao Li Huaqiang chu Xuefei Zhou Yalei Zhang State Key Laboratory of Pollution Control and Resource Reuse College of Environmental Science and EngineeringTongji UniversityShanghai 200092China Shanghai Institute of Pollution Control and Ecological Security Tongji UniversityShanghai 200092China Baowu Water Technology Co. Ltd.Shanghai 201999China

Microbial communities play crucial roles in pollutant removal and system stability in biological systems for coking wastewater(CWW)treatment,but a comprehensive understanding of their structure and functions is still lacking.A five month survey of four sequential bioreactors,anoxic 1/oxic 1/anoxic 2/oxic 2(A1/O1/A2/O2),was carried out in a full-scale CWW treatment system in China to elucidate operational performance and microbial *** results showed that A1/O1/A2/O2 had excellent and stable performance for nitrogen *** total nitrogen(TN;(17.38±6.89)mgL1)and ammonium-nitrogen(NH4 t-N;(2.10±1.34)mg·L^(-1))in the final biological effluent satisfied the Chinese national standards for *** analysis of 16S ribosome RNA(rRNA)sequencing and metagenomic sequencing showed that the bacterial communities and metagenomic function profiles of A1 and O1 shared similar functional structures,while those of A2 significantly varied from those of other bioreactors(prification during the primary anoxic-oxic(AO)stage and Azoarcus and Thauera acted as important denitrifiers in *** cycling-related enzymes and genes work in the A1/O1/A2/O2 ***,the hao genes catalyzing hydroxylamine dehydrogenase(EC 1.***.2.6)and the napA and napB genes catalyzing nitrate reductase(EC 1.***.6.1)played important roles in the nitrification and denitrification processes in the primary and secondary AO stages,*** mixed liquor suspended solids(MLSS)/total solids(TS),TN removal rate(RR),total organic carbon(TOC)(RR),and NH_(4)^(+)t-N(RR)were the most important environmental factors for regulating the structure of core bacterial genera and nitrogen-cycling *** were the potential main participants in nitrogen metabolism in the A1/O1/A2/O2 system for CWW *** study prov

关键词： Coking wastewater Full-scale Microbial community Metagenomic sequencing Nitrogen-cycling genes Environmental factor