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NiCo/Al_(2)O_(3)nanocatalysts for the synthesis of 5-amino-1-pentanol and 1,5-pentanediol from biomass-derived 2-hydroxytetrahydropyran

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Green Chemical Engineering 2024年第1期5卷 119-131页

作者： Jian Yang Jia zhang Enrico Benassi Xuemei Li Hailong liu weiguo Fang junying tian Chungu Xia Zhiwei Huang State Key Laboratory for Oxo Synthesis and Selective Oxidation Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou730000China School of Petrochemical Engineering Lanzhou University of TechnologyLanzhou730050China Novosibirsk State University Novosibirsk630090Russia University of Chinese Academy of Sciences Beijing100049China

Al_(2)O_(3)-supported monometallic Ni,Co,and bimetallic Ni-Co nanocatalysts originated from layered double hydroxide precursors were synthesized by co-precipitation method,and used for the synthesis of useful 5-amino-1-pentanol(5-AP)and 1,5-pentanediol(1,5-PD)by reductive amination(RA)or direct hydrogenation of biofurfuralderived 2-hydroxytetrahydropyran(2-HTHP),*** both reactions,the yield of the target products decreased monotonously with the increasing amounts of Co in the NiCo/Al_(2)O_(3)catalysts,owing probably to the replacement of highly reactive Ni by Co component with inferior hydrogenation activity at the low reaction temperature of 60℃.However,the incorporation of Co could improve the reducibility of the NiCo/Al_(2)O_(3)bimetallic catalysts and promote the reaction stability of the catalysts,especially for Ni_(2)Co1/Al_(2)O_(3),in both reactions with over 180 h *** of the catalysts before and after the reaction showed that the incorporating Co could inhibit the sintering of metal particles and hinder the surface oxidation of the more reactive Ni0species,thanks to the formation of Ni-Co alloy in the bimetallic ***-based modeling of the reaction mechanisms is also performed,supporting the reaction pathway proposed previously and also the much higher activity of Ni in the RA of 2-HTHP as compared with Co.

关键词： NiCo bimetallic catalysts Layered double hydroxide Reductive amination Amino alcohol Quantum chemical calculations

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Effect of Heat Treatment on High Temperature Stress Rupture Strength of Brazing Seam for Nickel-base Superalloy

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Journal of University of Science and Technology Beijing 2001年第2期8卷 123-125页

作者： junying zhang, zhongtai zhang, jisheng sun, xiaofang liu, wei tian (State Key Laboratory of New Ceramics and Fine Processing, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084, China) (Beijing institute of aeronautical Tsing Hua Univ Dept Mat Sci & Engn State Key Lab New Ceram & Fine Proc Beijing 100084 Peoples R China Inst Aeronaut Mat Beijing 100095 Peoples R China Univ Sci & Technol Beijing Mat Sci & Engn Sch Beijing 100083 Peoples R China

In order to enhance the high-temperature stress rupture strength of brazing seam by heat treatment, it was diffusion treated, then solution heat treated, and finally aging treated. The microstructure of brazing seam especially morphology of gamma ' phase and boride was observed and the strength of brazing seam was measured in this process. The results show that heat treatment can enhance high-temperature stress rupture strength by improving the microstructure of brazing seam. The strength of brazing seam after solution heat treatment decreases in comparison with that only after diffusion treatment while aging treatment after solution heat treatment increases the strength of brazing seam.

关键词： wide-gap brazing high temperature stress rupture strength microstructure nickel-base superalloy

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Microstructural evolution and mechanical properties of duplex-phase Ti6242 alloy treated by laser shock peening

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Transactions of Nonferrous Metals Society of China 2024年第8期34卷 2521-2532页

作者： Pu-ying SHI Xiang-hong liu Yong REN Zeng tian Feng-shou zhang wei-feng HE institute of Aeronautics Engine School of Mechanical EngineeringXi’an Jiaotong UniversityXi’an 710049China Western Superconducting Technologies Co. Ltd.Xi’an 710018China School of aeronautical Engineering Air Force Engineering UniversityXi’an 710038China

The effects of laser shock peening(LSP)on the microstructural evolution and mechanical properties of the Ti6242 alloy,including the residual stress,surface roughness,Vickers microhardness,tensile mechanical response,and high-cycle fatigue properties,were *** results showed that the LSP induced residual compressive stresses on the surface and near surface of the *** maximum surface residual compressive stress was−661 MPa,and the compressive-stress-affected depth was greater than 1000μ*** roughness and Vickers micro-hardness increased with the number of shocks,and the maximum hardness-affected depth was about 700μm after three LSP *** enhanced the fraction of low-angle grain boundaries,changed the grain preferred orientations,and notably increased the pole density ofαphase on the near surface from 2.41 to *** surface hardness values of the LSP samples increased with the increase of the number of shocks due to work hardening,while the LSP had a limited effect on the tensile *** high-cycle fatigue life of the LSP-treated sample was significantly enhanced by more than 20%compared with that of the untreated sample,which was caused by the suppression of the initiation and propagation of fatigue cracks.

关键词： duplex-phase Ti6242 alloy surface modification laser shock peening gradient microstructure high-cycle fatigue properties

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Influence of layer thickness on formation quality,microstructure,mechanical properties,and corrosion resistance of WE43 magnesium alloy fabricated by laser powder bed fusion

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Journal of Magnesium and Alloys 2024年第4期12卷 1367-1385页

作者： Bangzhao Yin Jinge liu Bo Peng Mengran Zhou Bingchuan liu Xiaolin Ma Caimei Wang Peng Wen Yun tian Yufeng Zheng State Key Laboratory of Tribology in Advanced Equipment Beijing100084China Department of Mechanical Engineering Tsinghua UniversityBeijing 100084China institute for Precision Medicine Tsinghua UniversityBeijing102218China Department of Orthopaedics Peking University Third HospitalBeijing 100191China Beijing AKEC Medical Co. Ltd.Beijing 102200China School of Materials Science and Engineering Peking UniversityBeijing 100871China Engineering Research Center of Bone and Joint Precision Medicine Ministry of EducationBeijing 100191China

Laser powder bed fusion(L-PBF)of Mg alloys has provided tremendous opportunities for customized production of aeronautical and medical *** thickness(LT)is of great significance to the L-PBF process but has not been studied for Mg *** this study,WE43 Mg alloy bulk cubes,porous scaffolds,and thin walls with layer thicknesses of 10,20,30,and 40μm were *** required laser energy input increased with increasing layer thickness and was different for the bulk cubes and porous *** tended to occur at the connection joints in porous scaffolds for LT40 and could be eliminated by reducing the laser energy *** thin wall parts,a large overhang angle or a small wall thickness resulted in porosity when a large layer thicknesses was used,and the porosity disappeared by reducing the layer thickness or laser energy input.A deeper keyhole penetration was found in all occasions with porosity,explaining the influence of layer thickness,geometrical structure,and laser energy input on the *** the samples achieved a high fusion quality with a relative density of over 99.5%using the optimized laser energy *** increased layer thickness resulted to more precipitation phases,finer grain sizes and decreased grain *** the similar high fusion quality,the tensile strength and elongation of bulk samples were significantly improved from 257 MPa and 1.41%with the 10μm layer to 287 MPa and 15.12%with the 40μm layer,in accordance with the microstructural *** effect of layer thickness on the compressive properties of porous scaffolds was ***,the corrosion rate of bulk samples accelerated with increasing the layer thickness,mainly attributed to the increased number of precipitation phases.

关键词： Magnesium alloy WE43 Laser powder bed fusion Layer thickness Process optimization

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高温氧化对粉末高温合金微观结构和疲劳性能影响研究

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推进技术 2024年第1期45卷 185-200页

作者：张禄余志伟陈阳张磊成江荣田高峰宋迎东南京航空航天大学能源与动力学院江苏南京210016 北京航空材料研究院先进高温结构材料重点实验室北京100095

为了探究涡轮盘用粉末高温合金表面氧化对其低周疲劳性能的影响,分别针对第三代镍基粉末高温合金的粗晶(Coarse grain,CG)和细晶(Fine grain,FG)材料开展氧化时间对其疲劳性能影响机理的研究。通过在700℃空气环境下开展不同时长的高温... 详细信息

为了探究涡轮盘用粉末高温合金表面氧化对其低周疲劳性能的影响,分别针对第三代镍基粉末高温合金的粗晶(Coarse grain,CG)和细晶(Fine grain,FG)材料开展氧化时间对其疲劳性能影响机理的研究。通过在700℃空气环境下开展不同时长的高温预氧化实验和低周疲劳(Low-cycle fatigue,LCF)实验,使用SEM和EDS表征LCF断口、表面氧化层结构成分及其强化相形貌变化,揭示LCF裂纹萌生机理。实验结果表明,氧化层厚度随氧化时间而增加,氧元素以氧化侵入的形式进入基体;相同氧化时间下,CG抗氧化性能优于FG;疲劳裂纹萌生于氧化侵入和亚表面夹杂物等应力集中部位,在实验温度下LCF寿命受氧化作用和夹杂物共同影响;高温氧化作用下氧化层呈现分层结构,外层为NiO,中间层为含有Cr_(2)O_(3),TiO_(2)等复杂氧化物及尖晶石相(NiCr_(2)O_(4))的混合层,内层为Al_(2)O_(3);CG二次γ’相氧化后平均尺寸增加,FG二次γ’相平均尺寸没有明显的变化,但两种组织氧化后在晶界附近均观察到长条状的二次γ’相,表明高温氧化作用下晶界优先遭到破坏。

关键词：涡轮盘镍基粉末高温合金低周疲劳寿命高温氧化强化相

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试验温度对镍基单晶高温合金裂纹扩展行为的影响

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稀有金属材料与工程 2024年第7期53卷 1874-1881页

作者：李乐宇田福政李振张金刚邓志伟陈星刘新灵中国航发北京航空材料研究院北京100095

研究了DD6镍基单晶高温合金从530℃到850℃的疲劳裂纹稳定扩展行为。疲劳裂纹扩展试样沿[001]方向平行于受拉的加载轴。通过扫描电子显微镜研究疲劳裂纹扩展试验后的断口形貌,并根据形貌特点分为源区、预制裂纹区、稳定扩展区以及快速... 详细信息

研究了DD6镍基单晶高温合金从530℃到850℃的疲劳裂纹稳定扩展行为。疲劳裂纹扩展试样沿[001]方向平行于受拉的加载轴。通过扫描电子显微镜研究疲劳裂纹扩展试验后的断口形貌,并根据形貌特点分为源区、预制裂纹区、稳定扩展区以及快速扩展区。通过电子背散射衍射技术研究垂直于断口的剖面塑性变形情况。通过透射电子显微镜观察断口附近位错机制随温度的变化。结果表明,受温度场、应力场以及暴露时间的作用,在650℃时发生氧化,且在650℃至760℃之间,由于γ′相的弱化,在γ与γ′相中形成大量连续的位错,导致合金氧化加剧,同时760℃下疲劳扩展寿命显著下降。

关键词：镍基单晶高温合金疲劳性能裂纹扩展位错运动机制

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Recovering REEs from NdFeB wastes with high purity and efficiency by leaching and selective precipitation process with modified agents

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Journal of Rare Earths 2019年第2期37卷 205-210页

作者： Yilan tian Zhongwu liu Guoqing zhang School of Materials Science and Engineering South China University of Technology Science and Technology on Advanced High Temperature Structural Materials Laboratory Beijing Institute of Aeronautical Materials

A leaching and selective precipitation approach is proposed in this work to recover rare earth elements(REEs) from NdFeB magnet wastes collected from industry. Hydrochloric acid and oxalic acid were employed as the leaching and precipitation agents, respectively. Hexamethylenetetramine(HMTA) or tartaric acid was used as the chelating agent during leaching. Both leaching and precipitation processes were optimized individually. For leaching process, the effects of two different chelating agents, the concentrations of leaching agent, chelating agent, and temperature on the extraction and recovery yields were investigated. The optimized process based on the factorial experiment was determined to be the hydrochloric acid concentration of 6 mol/L, the tartaric acid concentration of 50 g/L, and the temperature of 313.K, by which the extraction yields of Fe and REEs up to 67.99% and 99.27%, respectively, are obtained. For the precipitation process, the optimized oxalic acid dosage and pH value were also determined. The produced RE oxide products have the purity and recovery yield up to 95.83% and 90.18%,respectively. These results indicate that the present method with low acid consumption and high product purity has advantages over many other approaches for REE recovery.

关键词： Rare-earth permanent magnet Nd-Fe-B Waste management Recovery Leaching Precipitation

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Nanoarchitectonics of MnO_(2)nanotubes as sea urchin-like aggregates for dielectric response and microwave absorption with a wide concentration domain

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Nano Research 2023年第2期16卷 2604-2610页

作者： Zhi-Ling Hou Kunrong Du Yiqin zhang Song Bi junying zhang College of Mathematics and Physics&Beijing Key Laboratory of Environmentally Harmful Chemical Analysis Beijing University of Chemical TechnologyBeijing 100029China 501 Department Xi’an Research Institute of High-TechXi’an 710025China

Designing highly reliable and practical microwave absorbers is one of the most important research directions in the microwave absorbing *** absorbents suffer from concentration-sensitivity and environmental-sensitivity dilemmas in practical ***,sea urchin-like aggregates of MnO_(2)nanotubes were synthesized by a simple hydrothermal method,which exhibit an outstanding impedance matching *** composites based on sea urchin-like aggregates of MnO_(2)nanotubes show excellent microwave absorption performance in a wide concentration domain from 20 wt.%to 70 wt.%,corresponding to electrical conductivities from 1.86×10^(−7)to 1.85×10^(−5)S/*** a wide concentration range of absorbent for excellent microwave absorption is mainly attributed to the beneficial impedance matching properties of sea urchin-like aggregates of hollow nanotubes.A competitive absorption bandwidth of 3.36 GHz is achieved at 1 mm thickness,which can be broadened to 13.4 GHz by structural *** work shows a new scheme for designing reliable and practical microwave absorbers benefit from the wide absorbent concentration domain.

关键词： MnO_(2)nanotubes sea urchin-like aggregates broadband microwave absorption wide filling range

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Stachyose modulates gut microbiota and alleviates DSS-induced ulcerative colitis in mice

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Food Science and Human Wellness 2023年第6期12卷 2211-2220页

作者： Chen Wang junying Bai Botao Wang Leilei Yu Fengwei tian Jianxin Zhao Hao zhang Huayi Suo wei Chen Qixiao Zhai College of Food Science Southwest UniversityChongqing 400715China State Key Laboratory of Food Science and Technology Jiangnan UniversityWuxi 214122China School of Food Science and Technology Jiangnan UniversityWuxi 214122China Bloomage Biotechnology Co. Ltd.Jinan 250000China National Engineering Research Center for Functional Food Jiangnan UniversityWuxi 214122China Wuxi Translational Medicine Research Center and Jiangsu Translational Medicine Research institute Wuxi Branch Wuxi 214122China

Stachyose is a prebiotic that traditionally extracted from plants,such as *** has been demonstrated to alleviate intestinal inflammation by regulating gut microbiota,but the mechanism has been *** research aims to detect the potential mechanism of stachyose in alleviating the severity of ulcerative colitis(UC).The results indicated that the administration of stachyose could recover the body weight,protect against the colonic tissue damage,reduce the pro-inflammatory cytokines levels,and reverse the histological abnormalities in UC *** stachyose could restore dextran sulfate sodium(DSS)-induced disturbance in intestinal ***,the metabolome result of serum samples showed that stachyose treatment significantly altered serum metabolites against inflammatory responses in colitis ***,a significant correlation can be found between 23 metabolite biomarkers and 18 differential *** results provided a strong foundation for the future study of the protective role of stachyose in maintaining intestinal homeostasis.

关键词： Stachyose Prebiotic Colitis Metabonomics Gut microbiota

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单壁碳纳米管/聚醚酰亚胺电磁屏蔽薄膜的制备与性能

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物理学报 2024年第17期73卷 277-284页

作者：王天赐夏乾善黄信佐王永正刘斌张晋通黎涛哈尔滨理工大学电气与电子工程学院工程电介质及其应用教育部重点实验室哈尔滨150080 中国航空工业集团公司济南特种结构研究所济南250023

在实际应用中,柔性、轻质、高性能是聚合物基电磁屏蔽材料应具备的特点.目前,制备兼具优异电导率、电磁屏蔽性能和力学性能的聚合物基电磁屏蔽材料仍然是一个巨大挑战.因此,本工作以单壁碳纳米管和聚醚酰亚胺为原料,通过静电纺丝和真空... 详细信息

在实际应用中,柔性、轻质、高性能是聚合物基电磁屏蔽材料应具备的特点.目前,制备兼具优异电导率、电磁屏蔽性能和力学性能的聚合物基电磁屏蔽材料仍然是一个巨大挑战.因此,本工作以单壁碳纳米管和聚醚酰亚胺为原料,通过静电纺丝和真空辅助过滤的方法制备了单壁碳纳米管/聚醚酰亚胺复合薄膜.通过调控单壁碳纳米管的面密度,复合薄膜的电导率可以提升至1866 S/cm.对于电磁屏蔽性能,单壁碳纳米管/聚醚酰亚胺复合薄膜在Ku波段(12-18 GHz)的总电磁屏蔽效能为75.78-81.83 dB,高于纯单壁碳纳米管薄膜的电磁屏蔽效能(65.19-69.81 dB).由于聚醚酰亚胺纤维和单壁碳纳米管之间形成了界面,在一定的单壁碳纳米管面密度范围内,界面越多,消耗的电磁波能量越多.对于力学性能,单壁碳纳米管/聚醚酰亚胺薄膜的最大拉伸强度和断裂伸长率分别为28.52 MPa和7.91%,是单壁碳纳米管薄膜的1.13.和1.5倍,随着单壁碳纳米管面密度的增大,单壁碳纳米管之间的相互作用以及聚醚酰亚胺纤维和单壁碳纳米管在界面处的相互作用对复合薄膜的力学性能起到了一定的增强作用.单壁碳纳米管/聚醚酰亚胺复合薄膜作为一种优异的聚合物基电磁屏蔽复合材料,可用于如精密电子仪器的防护和可穿戴电子设备等领域.

关键词：单壁碳纳米管聚醚酰亚胺静电纺丝电磁屏蔽

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