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Enhancement of comprehensive properties of Nb–Si based in-situ composites by Ho rare earth doping

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Rare metals 2024年第9期43卷 4508-4520页

作者： Wei Wei Qi Wang Rui-Run Chen Chao-Wen Zheng Yan-Qing Su National key laboratory for Precision Hot processing of metals School of Materials Science and EngineeringHarbin Institute of Technology

This study examines the microstructure,mechanical properties （with a focus on room-temperature toughness）, and oxidation resistance of Ho-doped NbDSi based in-situ composites. The base alloy consists of the coarse primary Nb5Si3phase and the Nb5Si3+Nbss （Nb solid solution） eutectic cells. Ho doping influences the solidification path. When the Ho doping is higher than0.2 at%, the alloys transform into eutectic alloys. Ho can be solid-solved in trace amounts in the Nbss phase. However, most of Ho forms a stable Ho oxide phase, which alleviates oxygen contamination problem to some ***, the interface separation between Ho oxide and other phases reduces the plastic deformation ***, with 0.4 at%Ho doping, the KQvalue is18.03 MPa·m1/2, which is 31.1%higher than that of the base alloy. The strength of the Ho-doped alloys does not deteriorate with an increase in toughness. However, the large network-like Ho2O3in the 0.8Ho alloy causes a decrease in toughness and strength. In addition, the Ho oxide phase effectively blocks the inward oxygen *** 0.8 at%Ho doping, the oxidation mass gain per unit area is 10.16 mg·cm2, which is 39.7%lower than that of the base alloy.

关键词： Ho Microstructure Nb–Si based composites Properties Rare earth elements

Enhancing the mechanical properties of casting eutectic high -entropy alloys via W addition

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International Journal of Minerals,Metallurgy and Materials 2024年第6期31卷 1364-1372页

作者： Xu Yang Dezhi Chen Li Feng Gang Qin Shiping Wu Ruirun Chen National key laboratory for Precision Hot processing of metals School of Material Science and EngineeringHarbin Institute of TechnologyHarbin 150001China

The effect of W element on the microstructure evolution and mechanical properties of Al_(1.25)CoCrFeNi3 eutectic high-entropy alloy and Al_(1.25)CoCrFeNi_(3-x)W_(x)(x=0,0.05,0.1,0.3,and 0.5;atomic ratio)high-entropy alloys(HEAs)were *** show that the Al_(1.25)CoCrFeNi_(3-x)W_(x) HEAs are composed of face-centered cubic and body-centered cubic(BCC)*** W content increases,the microstructure changes from eutectic to *** addition of W lowers the nucleation barrier of the BCC phase,decreases the valence electron concentration of the HEAs,and replaces Al in the BCC phase,thus facilitating the nucleation of the BCC *** results show that the addition of W greatly improves the mechanical properties,and solid-solution,heterogeneous-interface,and second-phase strengthening are the main strengthening *** yield strength,tensile strength,and elongation of the Al_(1.25)CoCrFeNi2.95W0.05 HEA are 601.44 MPa,1132.26 MPa,and 15.94%,respectively,realizing a balance between strength and *** fracture mode of the Al_(1.25)CoCrFeNi_(3-x)W_(x) HEAs is ductile–brittle mixed fracture,and the crack propagates and initiates in the BCC *** eutectic lamellar structure impedes crack propagation and maintains plasticity.

关键词： high-entropy alloy microstructure mechanical property fracture behavior

Diversification of interfaces triggered hydrogen storage properties enhancement

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Rare metals 2024年第5期43卷 2324-2330页

作者： Jia-Xin Zhang Xin Ding Rui-Run Chen Xiang-Feng Ma Wen-Chao Cao Yong Zhang Jing-Jie Guo National key laboratory for Precision Hot processing of metals Harbin Institute of TechnologyHarbin 150001China

Dual effects of grain refinement and alloying are achieved and the mechanism of"diverse interfaces reinforcement"for hydrogen storage Mg alloys is first *** interface reinforced Mg-Y-Zn-Al alloy for hydrogen storage is *** work figures out that the adventurous Al-rich phase exhibits an ordered face-centered cubic(FCC)structure with composition of(31±2)at%Y-(28±1)at%Zn-(41±3)at%Al,i.e.,Y_(3)Zn_(3)Al_(4),and an incoherent interface between Y3Zn3Al4phase and Mg substrate is observed.

关键词： hydrogen alloying alloy

Selective leaching of calcium from mechanically activated mixed rare earth concentrate

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Journal of Rare Earths 2024年第6期42卷 1149-1156,I0006页

作者： Jiang Liu Bingxue Chen Yuanqi Feng Yijun Cao Yukun Huang Yuan Shi Meng Li Zhongyuan Critical metals laboratory School of Chemical EngineeringZhengzhou UniversityZhengzhou450001China State key laboratory of Advanced processing and Recycling of Nonferrous metals Lanzhou University of TechnologyLanzhou730050China

The loss of rare earths(REs)takes place during the pre-decalcification process of mixed rare earth *** an effort to reduce such RE loss,a novel idea to improve the leaching selectivity of Ca to REs by applying selective mechanical activation was ***,regarding the key minerals affecting the leaching selectivity of Ca to REs,the differences in the mechanical activation behaviors of CaF_(2) and REFCO_(3) were studied,and we find that the lattice strain of CaF_(2) increases from 0.21%to 0.42%,whereas that of REFCO_(3) increases from 0.31%to 0.40%.Notably,CaF_(2) demonstrates a larger lattice strain than REFCO_(3),indicating greater mechanical activation energy storage and higher leaching ***,the HCl leaching process was studied.A significant leaching selectivity of Ca to REs,from 21.6 to 35.1,is achieved through mechanical *** Ca leaching rate reaches 80.7%when the RE loss is 2.3%in the activated *** study provides an novel approach for achieving selective extraction of specific components via mechanical activation pretreatment.

关键词： Mixed rare earth concentrate Pre-decalcification Selective mechanical activation Selective leaching

Revealing the Structure-Property Difference of Natural Rubber Prepared by Different Methods: Protein and Gel Content are key Factors

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Chinese Journal of Polymer Science 2024年第4期42卷 457-467页

作者： Shao-Qi Huang Jun-Qi Zhang Yong Zhu Ling-Min Kong Lu-Sheng Liao Fu-Quan Zhang Zheng-Tian Xie Jin-Rong Wu State key laboratory of Polymer Materials Engineering College of Polymer Science and EngineeringSichuan UniversityChengdu610065China Hainan provincial key laboratory of Natural Rubber processing Agricultural Products Processing Research Institute of Chinese Academy of Tropical Agricultural SciencesZhanjiang524001China

Natural rubber (NR) is widely used in various fields including aerospace, military industry and transportation due to its superior elasticity and comprehensive mechanical properties. Nonetheless, the commercial NR prepared by different methods usually exhibits different mechanical properties, primarily due to variations in processing conditions during the conversion from latex to bulk rubber material. Consequently, this poses challenges in scientific research and industrial production of NR. In order to assess the properties of various commercially available NR and identify key structural and compositional components, this study systematically compares and analyzes four representative NR raw materials: air dried sheet (ADS), ribbed smoked sheets (RSS), constant viscidity NR (CV), and whole field latex rubber (WF). The investigation focuses on evaluating their static mechanical behavior, SIC behavior, wear resistance, and fatigue resistance. The findings indicate that protein and gel content exhibit a crucial influence on the NR properties. These constituents contribute to the formation of a high-crosslinking density region, generating a heterogeneous network structure within the rubber. This structure amplifies strains during deformation, leading to earlier and stronger strain-induced crystallization (SIC). Among the four commercial NR brands, RSS demonstrates superior overall mechanical and dynamic properties owing to its high protein and gel content. This study serves as a valuable reference for comprehending the differences in properties among various commercial NR, thereby offering guidance for the actual processing and selection of NR.

关键词： Natural rubber processingmethod Protein Gel content Property

Hypoglycemic effect and the mechanism of action of a polysaccharide from sweet corncob in a high-fat diet and streptozotocin-induced diabetic mice

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Food Science and Human Wellness 2024年第3期13卷 1543-1555页

作者： Xin Wang Weiye Xiu Ye Han Zhili Wang Yu Luo Yongqiang Ma Heilongjiang provincial key laboratory of Cereals and Comprehensive processing of Cereal Resources College of Food EngineeringHarbin University of CommerceHarbin 150028China

Type 2 diabetes mellitus(T2DM)is a metabolic disease caused by a glycolipid metabolism disorder and isletβ-cell ***-80-I is a biologically active water-soluble polysaccharide isolated from sweet corncob,an agricultural *** hypoglycemic effects of SCP-80-I on T2DM mice and its mechanisms were investigated in this ***-80-I was found to significantly reduce blood glucose and lipid deposition levels in T2DM mice,as well as decrease serum leptin and increase adiponectin ***,real time-polymerase chain reaction(RT-PCR)and Western blotting results revealed that SCP-80-I could regulate the expression of several glycolipid metabolisms and insulin secretion genes and proteins,including 5'-AMP-activated protein kinase(AMPK),carnitine palmitoyltransferase I(CPTI),and acetyl coenzyme A carboxylase(ACC)in the liver and AMPK,sirtuin1(Sirtl),peroxisome proliferator-activated receptorycoactivator-1(PGC-1α),and uncoupling protein 2(UCP2)in the *** have a hypoglycemic effect,SCP-80-1 regulated glycolipid metabolism and islet cell function in the liver by regulating the AMPK/AC C/CPT1 signaling pathway and the AMPK/Sirt1/PGC-1αand AMPK/Sirtl/UCP2 signaling *** findings improve our understanding of polysaccharides derived from sweet corncob and the use of SCP-80-I in the production of hypoglycemic foods.

关键词： Sweet corn cob polysaccharide Type 2 diabetes Signal pathway 5’-AMP-activated protein kinase(AMPK)

Assembly of a core–shell MOF with stability into polyacrylamide hydrogel for boosting extraction of uranium from seawater

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Nano Research 2024年第4期17卷 3398-3406页

作者： Yucheng Song Huanhuan Tan Shiliang Qin Zhong Liu Chuntai Liu Changyu Shen Peipei Yang Songwei Li National Engineering Research Center for Advanced Polymer processing Technology Key Laboratory of Materials Processing and Mold(Ministry of Education)Zhengzhou UniversityZhengzhou 450002China key laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources Qinghai Provincial Key Laboratory of Resources and Chemistry of Salt LakesQinghai Institute of Salt LakesChinese Academy of SciencesXining 810008China

Efficient and selective extraction of uranium(U(VI))from seawater is essential for sustainable nuclear power *** study reports a novel adsorbent zeolitic imidazolate framework(ZIF)-67@SiO_(2)-A/polyacrylamide(PAM)which was synthesized by grafting the core–shell metal–organic frameworks(MOFs)-based nanostructures coated with the 3-aminopropyl triethoxysilane(APTES)functionalized SiO_(2)(SiO_(2)-A)onto PAM *** SiO_(2) shell was grown on the surface of MOF,which improved the acid-base resistance of *** introduction of ZIF-67@SiO_(2)-A enhances the specific surface area and adsorption efficiency of the *** ZIF-67@SiO_(2)-A/PAM shows remarkable adsorption capacity,fast adsorption kinetics,and good reusability for *** has excellent adsorption property(6.33 mg·g^(-1),30 d)in natural *** X-ray photoelectron spectroscopy(XPS),Fourier transform infrared(FTIR),energy dispersive spectroscopy(EDS)mappings,and density functional theory reveal that the coordination by N and O in ZIF-67@SiO_(2)-A/PAM with uranium is the main mechanism of uranium ***,ZIF-67@SiO_(2)-A/PAM has great potential to capture uranium from natural seawater.

关键词： hydrogel metal–organic frameworks core–shelled nanostructures uranium extraction from seawater

JA-mediated MYC2/LOX/AOS feedback loop regulates osmotic stress response in tea plant

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Horticultural Plant Journal 2024年第3期10卷 931-946页

作者： Junyan Zhu Hongrong Chen Lu Liu Xiaobo Xia Xiaomei Yan Xiaozeng Mi Shengrui Liu Chaoling Wei State key laboratory of Tea Plant Biology and Utilization/key laboratory of Tea Biology and Tea processing of Ministry of Agriculture/Anhui provincial laboratory of Tea Plant Biology and Utilization Anhui Agricultural UniversityHefeiAnhui 230036China

Osmotic stress caused by low-temperature,drought and salinity was a prevalent abiotic stress in plant that severely inhibited plant development and agricultural yield,particularly in tea *** acid(JA)is an important phytohormone involving in plant ***,underlying molecular mechanisms of JA modulated osmotic stress response remains *** this study,high concentration of mannitol induced JA accumulation and increase of peroxidase activity in tea *** transcriptome mined a JA signaling master,MYC2 transcription factor is shown as a hub regulator that induced by mannitol,expression of which positively correlated with JA biosynthetic genes(LOX and AOS)and peroxidase genes(PER).CsMYC2 was determined as a nuclei-localized transcription activator,furthermore,ProteinDNA interaction analysis indicated that CsMYC2 was positive regulator that activated the transcription of CsLOX7,CsAOS2,CsPER1 and CsPER3via bound with their promoters,*** of CsMYC2 expression resulted in a reduced JA content and peroxidase activity and osmotic stress tolerance of tea *** of CsMYC2 in Arabidopsis improved JA content,peroxidase activity and plants tolerance against mannitol ***,we proposed a positive feedback loop mediated by CsMYC2,CsLOX7 and CsAOS2 which constituted to increase the tolerance of osmotic stress through fine-tuning the accumulation of JA levels and increase of POD activity in tea plant.

关键词： Camellia sinensis Jasmonic acid(JA) MYC2 transcription factor Lipoxygenase(LOX) Osmotic stress Peroxidase(POD) Reactive oxygen species(ROS)

Microstructures and mechanical properties of laser-directed energy deposited CrCoNi medium-entropy alloy

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Rare metals 2024年第7期43卷 3286-3300页

作者： Wen-Jie Zhao Chang-Yu Liu Peng-Cheng Che Zhi-Liang Ning Hong-Bo Fan Jian-Fei Sun Yong-Jiang Huang Alfonso H.W.Ngan National key laboratory for Precision Hot processing of metals Harbin Institute of Technology Space Environment Simulation Research Infrastructure Harbin Institute of Technology Department of Mechanical Engineering The University of Hong Kong

The distinctive intrinsic heat treatment(IHT)originating from cyclic reheating in the laser-directed energy deposition(LDED) has attracted growing attention in recent *** this investigation,simulations and experimental characterizations were performed to examine the impact of IHT on the micros true ture and mechanical properties of LDED-fabricated CrCoNi medium-entropy alloy(MEA).The results show that the intensity of the IHT is proportional to the utilized laser energy density(LED).As the LED increased,significant dynamic recrystallization and grain refinement occurred within the alloy due to the enhanced intensity of ***,the high LED leads to severe hot cracking within the as-built MEA,resulting in inferior *** decreasing LED,the hot cracking was effectively ***,low LED weakened the intensity of IHT and consequently inhibited kinetic conditions of dynamic recrystallization,resulting in a heterogeneous grain structure characterized by multi-scale-sized *** structure provides significant hetero-deformation-induced hardening during plastic deformation,enabling the alloy to have a sustainable work-hardening *** expect that this work will have implications in taking full advantage of the unique IHT of the LDED process to fabricate ME As with excellent metallurgical quality and mechanical performance.

关键词： Intrinsic heat treatment Laser-directed energy deposition CrCoNi MEA Dynamic recrystallization Heterogeneous grain structure