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On the Blaschke Isoparametric Hypersurfaces in the Unit Sphere

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Acta Mathematica Sinica,English Series 2009年第4期25卷 657-678页

作者： xing xiao li feng yun zhang Department of Mathematics. He'nan Normal University Xinxiang 453007 P. R. China

Given an immersed submanifold x ： M^M → S^n in the unit sphere S^n without umbilics, a Blaschke eigenvalue of x is by definition an eigenvalue of the Blaschke tensor of x. x is called Blaschke isoparametric if its Mobius form vanishes identically and all of its Blaschke eigenvalues are constant. Then the classification of Blaschke isoparametric hypersurfaces is natural and interesting in the MSbius geometry of submanifolds. When n = 4, the corresponding classification theorem was given by the authors. In this paper, we are able to complete the corresponding classification for n = 5. In particular, we shall prove that all the Blaschke isoparametric hypersurfaces in S^5 with more than two distinct Blaschke eigenvalues are necessarily Mobius isoparametric.

关键词： Mobius form Blaschke eigenvalues Blaschke tensor Mobius metric Mobius second fundamental form

Metallurgy and Solidification Microstructure Control of Fusion-Based Additive Manufacturing Fabricated Metallic Alloys:A Review

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Acta Metallurgica Sinica(English Letters) 2024年第1期37卷 29-53页

作者： Qiang li xing-Ran li Bai-Xin Dong xiao-Long zhang Shi-li Shu feng Qiu Lai-Chang zhang Zhi-Hui zhang Key Laboratory of Bionic Engineering(Ministry of Education) and College of Bionic Science and EngineeringJilin UniversityChangchun130022China Institute of Structured and Architected Materials Liaoning Academy of MaterialsShenyang110167China Key Laboratory of Automobile Materials Ministry of Education and Department of Materials Science and EngineeringJilin UniversityChangchun130025China School of Mechanical and Aerospace Engineering Jilin UniversityChangchun130025China School of Engineering Edith Cowan University270 Joondalup DriveJoondalupPerthWA6027Australia

The metal-based additive manufacturing(AM),also referred to as metal 3D printing,has drawn particular interest because it enables direct creation,aided by computationally-directed path design,of intricate components with site-specific compositions and geometrical requirements as well as low buy-to-fly *** the last two decades,the objective of this revolutionary technology has been shifting from only“rapid prototyping”to advanced manufacturing of special high-end products or devices,which,in many aspects,outperform conventional manufacturing *** fusion-based AM,significant progress has been achieved in understanding the processing window of macroscopic scales,non-equilibrium metallurgy of mesoscale scales,and grain evolution of microscopic *** the versatile capacity of AM facilitates new avenues for discovering advanced materials and structures,their potential has still not been fully *** the unique non-equilibrium solidification during the AM process,coarse columnar grains with strong textures are usually developed along the build direction,which downgrades the mechanical *** push the limits of this digital manufacturing,this review attempts to provide in-depth and comprehensive overviews of the recent progress in understanding the evolution and control of the as-built microstructure that has been made recently and the challenges encountered during the AM process.

关键词： Additive manufacturing Temperature field Microstructure control Nanoparticles Functionally graded materials

Elaborating strengthen mechanism of Pt-Ir solid solution superalloy at finite temperature

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Rare Metals 2024年第3期43卷 1243-1256页

作者： Wei Yu xiao-Yu Chong yun-Xuan Zhou Meng-Di Gan Ying-Xue liang Yan Wei Ai-Min zhang Chang-Yi Hu xing-Yu Gao li Chen Hai-feng Song Jing feng Faculty of Materials Science and Engineering Kunming University of Science and TechnologyKunming650093China yunnan Precious Metals Laboratory Co.LTD Kunming650106China Laboratory of Computational Physics Institute of Applied Physics and Computational MathematicsBeijing100088China

Pt-Ir alloy is potential superalloys used above 1300℃because of their high strength and creep ***,the ductility of Pt-Ir alloy has rapidly deteriorated with the increase of Ir,resulting in poor *** work quantitatively evaluated the solid solution strengthening(SSS)and grain refinement strengthening(GRS)of Pt-Ir alloy using first-principles calculations combined with experimental ***,the stretching force constants in the second nearest neighbor region(SFC^(2nd))of pure Ir(193.7 eV·nm^(-2))are 3.40 times that of pure Pt(57.0 eV·nm^(-2)),i.e.,the interatomic interaction is greatly enhanced with the increase of Ir content,which leads to the decrease of ductility,and modulus misfit plays a dominant role in ***,the physical mechanisms responsible for the hardness(H_(V))of Pt-Ir alloy,using the power-law-scaled function of electron work function coupled SSS and GRS,are attributed to the electron redistribution caused by different Ir ***,a thorough assessment of the thermodynamic characteristics of Pt-Ir binary alloy was conducted,culminating in development of a mapping model that effectively relates enmposition,temperature and *** results revealed that the compressive strength incrcases with the Ir content,and the highest strength was observed in Pt_(0.25)Ir_(0.75).This study provides valuable insights into the Pt-Ir alloy system.

关键词： Elastic properties Phonon Solid solution strengthen Force constants CALPHAD

New material of Coniopteris simplex from the Middle Jurassic of the Ordos Basin,Inner Mongolia,China and implications on its spatio-temporal distribution and paleogeography

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Journal of Palaeogeography 2024年第2期13卷 199-211页

作者： yun-feng li Chang-Lu zhang Fei liang xiao Tan Fan-Hao Gong Chun-lin Sun Tao li Yu-ling Na Research Center of Paleontology and Stratigraphy Jilin UniversityChangchun 130026Jilin ProvinceChina College of Earth Sciences Jilin UniversityChangchun 130061Jilin ProvinceChina College of Paleontology Shenyang Normal UniversityShenyang 110034Liaoning ProvinceChina Key Lab of Evolution of Past life in NE Asia Ministry of Natural ResourcesShenyang Normal UniversityShenyang 110034Liaoning ProvinceChina Shenyang Center of Geological Survey China Geological SurveyShenyang 110034Liaoning ProvinceChina

Coniopteris simplex is a common component in many Jurassic ***,due to morphological variations in sterile fronds and incomplete preservation of reproductive organs,its classification has been controversial for a long ***,we present new material collected from the Middle Jurassic Yan’an Formation in the Ordos Basin,Inner *** new material reveals important morphological characters,including hemi-dimorphic fronds,two forms of sterile pinnae,short-stalked sori and sporangia on fertile fronds,annulus of sporangium composed of about 30 cells,in situ rounded triangular spores with protruded suture,and the lips of trilete laesura encircled by one or two rows of small *** on these observations,we emended the diagnosis of this common *** spatio-temporal distribution of Coniopteris simplex shows that the iconic species was restricted to the paleolatitudes ranging from 19.5°N to 48.9°N in the Northern Hemisphere during the Early—Late Jurassic,mainly distributed in the tropical to paratropical zones,and the paleolongitude ranging from 9.6°E to 129.3°E,which may be limited by the opening of the Viking Corridor and the splitting of the Central Atlantic Ocean.

关键词： Coniopteris simplex Yan'an Formation Middle Jurassic Inner Mongolia Paleogeography

Diabetes mellitus in patients with type 1 autoimmune pancreatitis at diagnosis and after corticosteroid therapy

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Hepatobiliary & Pancreatic Diseases International 2024年第4期23卷 393-398页

作者： Mei-Zi li Tao Guo yun-Lu feng Sheng-Yu zhang xiao-Yin Bai Xi Wu Kai Xu Ai-Ming Yang Department of Gastroenterology State Key Laboratory of Complex Severe and Rare DiseasesPeking Union Medical College HospitalPeking Union Medical College and Chinese Academy of Medical SciencesBeijing 100730China Department of Radiology Peking Union Medical College HospitalPeking Union Medical College and Chinese Academy of Medical SciencesBeijing 100730China

Background:A high prevalence of diabetes mellitus(DM)coexisting with autoimmune pancreatitis(AIP)is ***,evidence on the circumstances under which corticosteroid therapy(CST)for AIP improves or worsens DM is *** study aimed to demonstrate and identify predictors of DM control under the influence of ***:Patients diagnosed with type 1 AIP were enrolled from a prospectively maintained cohort and were classified into three groups according to the chronology in which AIP and DM were diagnosed:pre-existing DM(pDM),concurrent DM(cDM),and non-DM(nDM).The responses of DM to CST were assessed when corticosteroid was ceased or tapered to a maintenance dose and classified as‘improvement’and‘non-improvement’(including‘no change’and‘exacerbation’).Results:Among 101 patients with type 1 AIP,52(51.5%)patients were complicated with DM at the time of AIP diagnosis,with 36 patients in the cDM group and 16 patients in the pDM *** incidences of diffuse pancreatic swelling(72.2%)and pancreatic body/tail involvement(91.7%)were significantly higher in the cDM group than in both the pDM and nDM *** the 52 patients with DM,CST was administered in 48 *** logistic analysis identified that elevated serum gamma-glutamyl transferase(GGT)level at AIP diagnosis[odds ratio(OR)=0.032,95%confidence interval(CI):0.003-0.412,P=0.008]and pancreatic atrophy after CST(OR=0.027,95%CI:0.003-0.295,P=0.003)were negatively associated with DM control ***:Patients with diffuse pancreatic swelling and pancreatic body/tail involvement in pancreatitis tended to be complicated with cDM at AIP *** exerted a beneficial effect on the clinical course of DM in nearly half of the AIP patients complicated with DM at diagnosis,particularly in those without elevated serum GGT levels at diagnosis and who did not experience pancreatic atrophy after CST.

关键词： Type 1 autoimmune pancreatitis Diabetes mellitus Corticosteroid therapy Predictive factor Pancreatic atrophy

Synthesis of highly stable Ni nanoparticles via electrostatic self-assembly for enhanced hydrogen storage of MgH2

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Rare Metals 2024年第9期43卷 4356-4366页

作者： Qin-Ke Tang Jiang-Chuan liu Rui Shi yun-feng Zhu Ji-Guang zhang Ya-Na liu Jun Wang Yao zhang xiao-Hui Hu Zhi-Bin liu li-Quan li College of Materials Science and Engineering Jiangsu Collaborative Innovation Centre for Advanced Inorganic Function CompositesNanjing Tech University School of Materials Science and Engineering Southeast University

Magnesium-based hydrides have been widely recognized as an appropriate choice for solid-state hydrogen ***,its undesirable thermodynamics and sluggish hydrogenation/dehydrogenation kinetics are major bottlenecks for its ***,a highly stable and highly dispersed Ni-based catalyst （Ni/Al2O3/GN） was fabricated to promote the hydrogen storage performance of MgH2via the electrostatic effect of NiAl-LDH/GN precursor with a co-calcination reduction ***2-5wt % Ni/Al2O3/GN exhibits excellent hydrogen storage performance,releasing about 5.7 wt % hydrogen in 3500 s at 250℃,and can reach a saturation hydrogen absorption of about 6.15 wt% in 3000 s at 100℃.Furthermore,it also shows low dehydrogenation apparent activation energy of 89.1 and 118.2 kJ·***,the catalyst ensures the stability of both the physical phase and structure during ball milling and cycling *** role of each phase in Ni/Al2O3/GN on the hydrogen storage performance of MgH2was also discussed through experiments and theoretical calculation,and the synergistic catalytic mechanism of Ni/Al2O3/GN was clearly *** work provides a unique perspective for the preparation of highly stable and highly dispersible catalysts.

关键词： Catalytic mechanism Hydrogen storage performance Magnesium hydride Ni/Al2O3/GN

Deep insight of unique phase transition behaviors and mechanism in Zr_(2)Co-H isotope system with ultra-low equilibrium pressure

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Rare Metals 2024年第1期43卷 212-224页

作者： Yang liu Pan-Pan Zhou Xue-zhang xiao Jia-Cheng Qi Jia-Peng Bi Tiao Ying xing-Wen feng Yan Shi Wen-Hua Luo li-Xin Chen State Key Laboratory of Silicon Materials School of Materials Science and EngineeringZhejiang UniversityHangzhou 310027China Institute of Materials China Academy of Engineering PhysicsMianyang 621907China Key Laboratory of Advanced Materials and Applications for Batteries of Zhejiang Province Hangzhou 310013China

Efficient capture,safe storage and release of tritium from the international thermonuclear experimental reactor(ITER) reaction exhaust gas is a perplexing problem,and the development of an efficient tritium-getter material with ultra-low hydrogenation equilibrium pressure is considered as a reliable *** this work,Zr_(2)Co alloy was selected as a tritium-getter material and prepared through induction levitation *** performance test results show that Zr_(2)Co exhibits an ultra-low hydrogenation equilibrium pressure of 3.22 × 10^(-6) Pa at 25℃ and excellent hydriding kinetics under a low hydrogen pressure of 0.005 ***,unique phase transition behaviors were presented in Zr_(2)Co-H ***,Zr_(2)CoH_(5) formed by Zr_(2)Co hydrogenated at room temperature is initially decomposed into ZrH_(2) and ZrCoH_(3) at200 ℃.With the temperature increasing to 350 ℃,ZrCoH_(3)is dehydrogenated to ZrCo,and then ZrCo further reacts with ZrH_(2) at 650 ℃ to reform Zr_(2)Co and *** the staged phase transition pathways during dehydrogenation,the decomposition of Zr_(2)CoH_(5) occurs preferentially,which is well accordance with both the smallest reaction energy barrier and the maximum reaction spontaneity that are determined respectively from kinetics activation energy and thermodynamics Gibbs free ***,first principles calculation results indicate that the stronger binding of hydrogen in interstitial environments of ZrCoH_(3)and ZrH_(2) triggers the hydrogen-stabilized phase transformation of Zr_(2)CoH_(5).The unique phase transition mechanisms in Zr_(2)Co-H system can shed light on the further exploration and regulation of analogous staged phase transition of hydrogen storage materials.

关键词： Zr_(2)Co alloy Tritium-getter materials Ultralow equilibrium hydrogen pressure Phase transition mechanism

Time-resolved ultra-small-angle X-ray scattering beamline(BL10U1)at SSRF

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Nuclear Science and Techniques 2024年第2期35卷 6-19页

作者： Wen-Qiang Hua Chun-Ming Yang Ping Zhou feng Tian Jin-You lin Yu-Zhu Wang xiao-yun li Xia-Ran Miao Chun-Xia Hong Qiu-Shi Huang Xin-Tong Zhao Yong-feng Men Jie Wang xing-Yu Gao Xiu-Hong li Shanghai Synchrotron Radiation Facility Shanghai Advanced Research InstituteChinese Academy of SciencesShanghai 201204China Key Laboratory of Advanced Micro Structural Materials MOEInstitute of Precision Optical EngineeringSchool of Physics Science and EngineeringTongji UniversityShanghai 200092China State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China

The construction of a new beamline,BL10U1,was completed at the Shanghai synchrotron radiation facility in *** multipurpose beamline was designed to provide X-ray scattering techniques such as ultra-small-angle X-ray scattering(USAXS),small-angle X-ray scattering(SAXS),wide-angle X-ray scattering,and microfocus SAXS(μSAXS)for a broad user *** realize fast time-resolved USAXS experiments,the beamline adopted an in-vacuum undulator with a total length of 1.6 m as the photon *** in-house cryogenic-cooled double multilayer monochromator was installed to deliver a photon flux of approximately 10^(13) photons/s at a photon energy of 10 *** three-year successful operation of this beamline demonstrated that the monochromator operated smoothly,as ***10U1 has three end stations in succession:USAXS end station,μSAXS end station,and end station for industrial *** minimum scattering vector q~0.0042 nm^(-1) at 10 keV can be achieved at the USAXS end station equipped with a 28 m-long and 1.8 m-diameter vacuum flight *** theμSAXS end station,a beam spot of less than 10×8μm was achieved for micro-SAXS *** contrast,in situ experimental instruments up to 5 m high and 8 m wide can be mounted at the industrial application end station,which offers industrial scientists the opportunity to use their large industrial ***10U1 opens up a new capability to investigate phenomena such as non-equilibrium and dynamic processes of materials with a wide length scale from angstroms to micrometers with millisecond time *** this paper,we also report beamline design considerations and commissioning results.

关键词： Synchrotron radiation Ultra-small-angle X-ray scattering Micro small-angle X-ray scattering USAXS Time resolved μSAXS

Cadherin-18 loss in prospermatogonia and spermatogonial stem cells enhances cell adhesion through a compensatory mechanism

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Zoological Research 2024年第5期45卷 1048-1060页

作者： xiao-xiao li Dan-Chen zhang Yan Wang Jian Wen xing-Ju Wang Yu-Lu Cao Ru Jiang Jia-Rui li Yi-Nuo li He-He liu Wen-Hai Xie Zheng-feng Xu Ping Hu Kang Zou Germline Stem Cells and Microenvironment Lab College of Animal Science and TechnologyNanjing Agricultural UniversityNanjingJiangsu 210095China Stem Cell Research and Translation Center Nanjing Agricultural UniversityNanjingJiangsu 210095China School of life Sciences and Medicine Shandong University of TechnologyZiboShandong 255000China Department of Prenatal Diagnosis Women’s Hospital of Nanjing Medical UniversityNanjing Maternity and Child Health Care HospitalNanjingJiangsu 210004China

Extracellular membrane proteins are crucial for mediating cell attachment,recognition,and signal transduction in the testicular microenvironment,particularly germline stem *** 18(CDH18),a type II classical cadherin,is primarily expressed in the nervous and reproductive ***,we investigated the expression of CDH18 in neonatal porcine prospermatogonia(ProSGs)and murine spermatogonial stem cells(SSCs).Disruption of CDH18 expression did not adversely affect cell morphology,proliferation,self-renewal,or differentiation in cultured porcine ProSGs,but enhanced cell adhesion and prolonged cell *** analysis indicated that the down-regulation of CDH18 in ProSGs significantly up-regulated genes and signaling pathways associated with cell *** further elucidate the function of CDH18 in germ cells,Cdh18 knockout mice were generated,which exhibited normal testicular morphology,histology,and *** analysis showed increased expression of genes associated with adhesion,consistent with the observations in porcine *** interaction of CDH18 withβ-catenin and JAK2 in both porcine ProSGs and murine SSCs suggested an inhibitory effect on the canonical Wnt and JAK-STAT signaling pathways during CDH18 ***,these findings highlight the crucial role of CDH18 in regulating cell adhesion in porcine ProSGs and mouse *** this regulatory mechanism provides significant insights into the testicular niche.

关键词： Extracellular signal Fertility Quiescency Wnt signaling pathway