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Effect of Microstructural Characteristics on Fracture Toughness in Direct Energy Deposited Novel Ti-6Al-4V-1Mo Alloy

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Acta Metallurgica Sinica(English Letters) 2024年第1期37卷 119-131页

作者： Chao Xia Kexin Zhao xin Zhou Yuqi he Panpan Gao hengxin Zhang Guangrui Gao Fengying Zhang Hua tan School of Material Science and Engineering Chang’an UniversityXi’an710064China Science and Technology on Plasma Dynamics Laboratory Air Force Engineering UniversityXi’an710038China State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an710072China Surface Material Protection Co. LtdXi’an710018China

Meeting the damage tolerance requirements for engineering-grade titanium alloys pose a significant challenge in achieving high fracture toughness in direct energy deposition(DED)titanium *** work primarily investigated the relationship between the microstructure and the fracture toughness of DED new Ti-6Al-4V-1Mo *** types of microstructures were designed via two process strategies:high-line energy density(he)and low-line energy density(LE).Relative to LE samples,he samples possess larger-sized microstructural characteristics(coarser grain boundaryα(α_(GB)),largerαcolonies,and coarserαlaths).Lessα/βphase boundaries were formed by coarserαlaths in the he samples,increasing the movement of dislocations,resulting in tensile strength decreasing from 1007.1 MPa(LE)to 930.8 MPa(he)and elongation increasing from 10.8%(LE)to 15.7%(he).Also,he samples exhibited an excellent fracture toughness of 114.0 MPa m^(1/2),significantly higher than that of LE samples(76.8 MPa m^(1/2)).An analysis of crack propagation paths was conducted to investigate the factors contributing to *** primary factor enhancing toughness is the frequent obstruction of cracks by coarseαGB and largeαcolonies in he ***,the pretty large-angle deflections induced by the superposition effect of coarseαGB and largeαcolonies play a vital of significant *** factors induced the long and tortuous high-energy pathways,which resulted in ultimately improved fracture *** discovered microstructural toughening mechanisms can serve as a reference for future studies involving titanium alloys,offering insights on how to enhance fracture toughness by achieving similar characteristics.

关键词： Direct energy deposition Ti-6Al-4V-1Mo Tensile properties Fracture toughness Crack propagation

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Electrical characteristics of a fractional-order 3×n Fan network

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Communications in Theoretical Physics 2024年第4期76卷 176-187页

作者： Zhi-Zhong tan xin Wang Department of Physics Nantong UniversityNantong 226019China

In this article a new achievement of fractional-order 3×n Fan networks is *** the first step,the RT-I method is used to derive the general formulae of the equivalent impedance of fractional-order 3×n Fan *** the second part,the effects of five system parameters(L,C,n,α and β)on amplitude-frequency and phase-frequency characteristics are *** the same time,the amplitude-frequency and phase-frequency characteristics of the fractional order 3×n Fan network are revealed by Matlab *** work has important theoretical and practical significance for resistor network models in the field of natural science and engineering technology.

关键词： fractional-order circuit amplitude-frequency characteristics phase-frequency characteristics RT-V theory

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Long-term Evolution of Solar Activity and Prediction of the Following Solar Cycles

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Research in Astronomy and Astrophysics 2024年第3期24卷 194-204页

作者： Pei-xin Luo Bao-Lin tan National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China

Solar activities have a great impact on modern high-tech systems,such as human aerospace activities,satellite communication and navigation,deep space exploration,and related scientific ***,studying the long-term evolution trend of solar activity and accurately predicting the future solar cycles are highly *** on the wavelet transform and empirical function fitting of the longest recorded data of the annual average relative sunspot number(ASN)series of 323 yr to date,this work decisively verifies the existence of the solar century cycles and confirms that its length is about 104.0 yr,and the magnitude has a slightly increasing trend on the timescale of several hundred *** on this long-term evolutionary trend,we predict solar cycles 25 and26 by using phase similar prediction *** for solar cycle 25,its maximum ASN will be about146.7±33.40,obviously stronger than solar cycle *** peak year will occur approximately in 2024,and the period will be about 11±1 *** for solar cycle 26,it will start around 2030,and reach its maximum between2035 and 2036,with maximum ASN of about 133.0±3.200,and period of about 10 yr.

关键词： Sun activity-Sun evolution-(Sun) sunspots-methods data analysis

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Interaction of yttrium barrier and calcium-rich phase on production and properties of WC precursor powders and alloys

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Journal of Rare Earths 2024年第1期42卷 228-236,I0008页

作者： Wen he Dunqiang tan Zhiqiang Yi Zhiqiang Liu School of Materials Science and Engineering Nanchang UniversityNanchang330031China Instrumental Analysis Center of Nanchang Hangkong University Nanchang330063China

In order to reduce or eliminate the adverse effects of calcium impurity,the interaction of Ca and rare earth Y co-doping on the preparation of WC-Co cemented carbides was investigated.X-ray diffraction,scanning electron microscopy and transmission electron microscopy were employed to analyze the phase compositions,particle sizes and morphologies of them,*** results show that the second type of"yttrium barrier effect"is observed and the adverse influence of Ca-rich phase on tungsten powder can be eliminated by *** flexural strength and fracture toughness of YG6-0.01%Ca+0.09%Y alloy are 2199.5 MPa and 11.49 MPa·m^(1/2),showing improvement of 6.5% and 2.7% compared to YG6 alloy,*** evolutions of Ca-rich phase and Y-rich phase at the every alloy preparation stage of WO_(3),W,WC and cemented carbides are ***,the strengthening mechanism of WC-Co cemented carbide with co-addition of Ca and Y is proposed.

关键词： Yttrium barrier effect Ca-rich phase WC-Co cemented Carbide Microstructures Mechanisms Rare earths

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Restoring cosmological concordance with axion-like early dark energy and dark matter characterized by a constant equation of state?

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Communications in Theoretical Physics 2024年第7期76卷 76-84页

作者： Yan-Hong Yao xin-he Meng School of Physics and Astronomy Sun Yat-sen University School of Physics Nankai University

The Hubble tension persists as a challenge in cosmology. Even early dark energy（EDE） models,initially considered the most promising for alleviating the Hubble tension, fall short of addressing the issue without exacerbating other tensions, such as the S8tension. Considering that a negative dark matter（DM） equation of state（EoS） parameter is conducive to reduce the value of the σ8parameter, we extend the axion-like EDE model in this paper by replacing the cold dark matter（CDM） with DM characterized by a constant EoS wdm（referred to as WDM hereafter）.We then impose constraints on this axion-like EDE extension model, along with three other models: the axion-like EDE model, ΛWDM, and ΛCDM. These constraints are derived from a comprehensive analysis incorporating data from the Planck 2018 cosmic microwave background, baryon acoustic oscillations, and the Pantheon compilation, as well as a prior on H0（i.e. H0= 73.04 ± 1.04, based on the latest local measurement by Riess et al） and a Gaussianized prior on S8（i.e. S8= 0.766 ± 0.017, determined through the joint analysis of KID1000+BOSS+2dLenS）. We find that although the new model maintains the ability to alleviate the Hubble tension to ～1.4σ, it still exacerbates the S8tension to a level similar to that of the axion-like EDE model.

关键词： early dark energy Hubble tension noncold dark matter S8 tension

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Protective Effects of Phellodendron Species on Bone health: A Novel Perspective on Their Potentials in Treating Osteoporosis and Osteoarthritis

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Chinese Journal of Integrative Medicine 2024年第4期30卷 379-384页

作者： xin Li tan Guo-yao ZHANG Qiang ZHANG Qun Good Clinical Practice Development Guangdong Provincial Key Laboratory of Bone and Joint Degeneration DiseasesThe Third Affiliated Hospital of Southern Medical UniversityGuangzhou(510630)China Department of Pharmacy Sun Yat-sen Memorial HospitalSun Yat-sen UniversityGuangzhou(510120)China

Phellodendron(PN)species,traditionally used in Chinese medicine for centuries,hold promise as a potential treatment for osteoporosis(OP)and osteoarthritis(OA)due to their bioactive *** bioactive compounds,including berberine and palmatine,exhibit anti-inflammatory,antioxidant,and bone-protective properties,contributing to their potential therapeutic benefits in promoting bone health and preventing bone ***,challenges such as the need for standardized preparation and dosing,limited clinical studies,and potential interactions with other medications hinder their clinical ***,the rich history of PN species in Chinese medicine provides a promising foundation for future investigation into their potential as alternative treatments for OP and *** research is needed to fully understand the underlying mechanisms of action and explore the clinical implications of PN for bone health.

关键词： Phellodendron species bone health osteoporosis osteoarthritis review

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Spacelike Framed Curves with Lightlike Components and Singularities of Their Evolutes and Focal Surfaces in Minkowski 3-space

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Acta Mathematica Sinica,English Series 2024年第6期40卷 1521-1532页

作者： Peng Cheng LI Dong he PEI xin ZHAO School of Mathematics and Statistics Northeast Normal UniversityChangchun 130024P.R.China Department of Mathematics Harbin Institute of TechnologyWeihai 264209P.R.China School of Mathematics and Statistics Qingdao UniversityQingdao 266071P.R.China

In this paper,we define the evolute and focal surface of a spacelike framed curve with lightlike components in Minkowski *** is a generalization of the previous results of regular spacelike curves,since singularities are allowed in the original spacelike curves studied by spacelike framed curves with lightlike ***,we show a new geometric invariant to characterise singularities of the focal ***,the classification theorem and recognition theorem for the singularities of the focal surface in generic are also given.

关键词： Evolutes focal surfaces spacelike framed curves singularities

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Identification of the optimal doping position of hetero-atoms in chalcogen-doped Fe-N-C catalysts for oxygen reduction reaction

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Particuology 2024年第6期89卷 99-108页

作者： Weihao Liu Huanhuan he Qingtao Liu xin Wan Jianglan Shui School of Materials Science and Engineering Beihang UniversityBeijing100191China School of Space and Environment Beihang UniversityBeijing102206China Tianmushan Laboratory Hangzhou310023China

The excellent oxygen reduction reaction(ORR)activity of Fe–N–C catalysts in acidic media makes them potential for low-cost proton exchange membrane fuel *** recent years,it has been shown that heteroatoms(B,O,S,P,Cl,F,etc.)can be used as electron-withdrawing groups to modulate the planar structure and electron distribution of the Fe–Nx active sites to achieve simultaneous improvement of catalytic activity and ***,the optimal location of the heteroatoms remains ***,taking chalcogen heteroatoms(S and Se)as an example,we control the doping positions and investigate their effect on the ORR performance of the Fe–N–C *** first coordination shell of the iron single atom is identified as the optimal doping *** optimized catalysts Fe–N_(3)Se_(1)/NC and Fe–N_(3)Se_(1)/NC demonstrate improved activity and stability in both half cells and fuel *** work provides insights into the enhancement mechanism of heteroatom doping in single-atom catalysts.

关键词： Oxygen reduction reaction Fe-N-C catalysts hetero-atom doping Doping position Enhancement mechanism

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Mechanisms of inclusion-induced pitting of stainless steels:A review

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Journal of Materials Science & Technology 2024年第1期168卷 143-156页

作者： Yangting Sun xin tan Rulei Lan Guoyong Ran Jin Li Yiming Jiang Department of Materials Science State Key Laboratory of Molecular Engineering of PolymersFudan UniversityShanghai 200438China

Pitting is a common type of localized corrosion in passive alloys that can cause rapid failure of material or *** the case of stainless steels,non-metallic inclusions have been identified as the most susceptible sites for pitting,and have therefore garnered significant *** review critically ex-amines the issue of how inclusions induce pitting,with a particular focus on three mechanisms:sponta-neous dissolution of inclusions,active dissolution of Cr-depleted regions,and propagation of microcracks at the inclusion-matrix *** researchers have made significant strides in understanding these mechanisms over the past few decades,many gaps and controversies *** such as the ini-tial driving force of inclusion dissolution and factors affecting Cr-depleted regions require further ***,some old concepts and methods need to be revised to arrive at more credible *** review aims to delve deeply into these important issues and provide inspiration for future research.

关键词： Pitting Inclusion Stainless steel Localized corrosion MnS

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PARE:Privacy-Preserving Data Reliability Evaluation for Spatial Crowdsourcing in Internet of Things

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Computers, Materials & Continua 2024年第8期80卷 3067-3084页

作者： Peicong he Yang xin Yixian Yang School of Cyberspace Security Beijing University of Posts and TelecommunicationsBeijing100876China

The proliferation of intelligent,connected Internet of Things(IoT)devices facilitates data ***,task workers may be reluctant to participate in data collection due to privacy concerns,and task requesters may be concerned about the validity of the collected ***,it is vital to evaluate the quality of the data collected by the task workers while protecting privacy in spatial crowdsourcing(SC)data collection tasks with *** this end,this paper proposes a privacy-preserving data reliability evaluation for SC in IoT,named ***,we design a data uploading format using blockchain and Paillier homomorphic cryptosystem,providing unchangeable and traceable data while overcoming privacy ***,based on the uploaded data,we propose a method to determine the approximate correct value region without knowing the exact ***,we offer a data filtering mechanism based on the Paillier cryptosystem using this value *** evaluation and analysis results show that PARE outperforms the existing solution in terms of performance and privacy protection.

关键词： Spatial crowdsourcing privacy-preserving data evaluation IoT blockchain

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