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Synthesis of Diverse Oxetane Amino Acids via Visible-Light-Induced Photocatalytic Decarboxylative Giese-Type Reaction

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Chinese Journal of Chemistry 2024年第12期42卷 1341-1346页

作者： Haoliang Shi yi wan yongqiang Zhang Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism Shanghai Key Laboratory of New Drug Designand School of PharmacyEast China University of Science and TechnologyShanghai200237 China

The divergent synthesis of versatile 3,3′-disubstituted oxetane amino acids by utilizing visible-light-induced photocatalytic decarboxylative Giese-type reaction has been demonstrated.3-Methyleneoxetane-derived substrates are readily available in a single-step and highly reactive as radical acceptors,allowing the production of versatile oxetaneγ-andα-amino acids in high yields.A distinct ring strain release-driven radical addition mechanism was preliminarily *** preparative power was further highlighted by the application in the synthesis of oxetane-containing dipeptides and azetidine amino acids,as well as the transformation of the product into novel oxetane-containing spiro-heterocycle pharmacophore.

关键词： Photoredox catalysis Decarboxylative Giese-type reaction Oxetane amino acids Amino acids Synthesis Radical reactions

Toward qualification of additively manufactured metal parts:Tensile and fatigue properties of selective laser melted Inconel 718 evaluated using miniature specimens

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Journal of Materials Science & Technology 2022年第2期97卷 239-253页

作者： H.y.wan W.K.yang L.y.wang Z.J.Zhou C.P.Li G.F.Chen L.M.Lei G.P.Zhang Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of Sciences72 Wenhua RoadShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China Materials&Manufacturing Qualification Group Corporate TechnologySiemens Ltd.Beijing 100102China AECC Shanghai Commercial Aircraft Engine Manufacturing Co. LtdShanghai 201306China

Combined with the topology optimization,additive manufacturing can be used to fabricate metal parts with complex ***,due to the geometrical variations and microstructure heterogeneities of the additively manufactured metal parts,new standards with the use of miniature specimens are required for the evalutation of the spatial distribution of mechanical properties throughout the ***,we conduct a systematic investigation on tensile and fatigue properties of selective laser melted Inconel718 specimens with different thicknesses ranging from 0.1 mm to 1 mm.A“microstructure unit”that can well reflect the microstructure characteristic of selective laser melted materials is *** results reveal that premature necking with a dramatic drop in uniform elongation occurs if the ratio(t/d)of specimen thickness(t)to the"microstructure unit"size(d)is less than *** necking is mainly attributed to the transition of strain localization *** also propose a probabilistic statistical model for fatigue limit prediction based on the available fatigue *** is recommended that the criterion of t/d≥4 should be satisfied to ensure that the yield strength,the uniform elongation,and the fatigue limit determined by the miniature specimens are comparable with those determined by standard *** findings may provdie a guide to the establishment of miniature specimen-based standards toward the qualification of additively manufactured metal parts.

关键词： Selective laser melting Inconel 718 Miniature specimen Microstructure unit Thickness effect

Frobenius morphisms and stable module categories of repetitive algebras

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Science China Mathematics 2008年第2期51卷 169-184页

作者： DENG BangMing wan JinKui School of Mathematical Sciences Beijing Normal UniversityBeijing 100875China

Let k be the algebraic closure of a finite field $\mathbb{F}_q $ and A be a finite dimensional k-algebra with a Frobenius morphism F. In the present paper we establish a relation between the stable module category of the repetitive algebra ? of A and that of the repetitive algebra of the fixed-point algebra A F. As an application, it is shown that the derived category of A F is equivalent to the subcategory of F-stable objects in the derived category of A when A has a finite global dimension.

关键词： Frobenius morphism repetitive algebra stable module category derived category 16G10 18E30

Effect of y content and equal channel angular pressing on the microstructure, texture and mechanical property of extruded Mg-y alloys

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Journal of Magnesium and Alloys 2022年第1期10卷 210-224页

作者： W.yang G.F.Quan B.Ji y.F.wan H.Zhou J.Zheng D.D.yin Key Laboratory of Advanced Technologies of Materials Ministry of EducationSchool of Materials Science and EngineeringSouthwest Jiaotong UniversityChengduSichuan 610031China Nano and Heterogeneous Materials Center School of Materials Science and EngineeringNanjing University of Science and TechnologyNanjing 210094China International Joint Laboratory for Light Alloys(Ministry of Education) College of Materials Science and EngineeringShenyang National Laboratory for Materials ScienceChongqing UniversityChongqing 400044China

The microstructure, texture and mechanical property evolution of the extruded Mg-x y(x = 1, 5 wt.%) alloys during equal channel angular pressing(ECAP) were systematically investigated using an optical microscope, electron backscatter diffraction(EBSD) and uniaxial tensile test. The Mg-y alloys exhibited a weakened basal texture before the ECAP, and the texture was further weakened with the max basal poles dispersed along ~45° between the extrusion direction and the transverse direction after the ECAP. The Mg-5 y alloys always exhibited a finer grain size comparing to that of Mg-1 y for the same ECAP process. With a proper ECAP process, both the strength and elongation of Mg-5 y alloy could be improved simultaneously after the ECAP, i.e., the yield strength(273.9 ± 1.2 MPa), ultimate strength(306.4 ± 3.0 MPa),and elongation(23.9 ± 1.0%) were increased by 10%, 6%, and 72%, respectively, comparing to that before the ECAP. This was considered to be arose from the combined effects of grain refinement, significant improved microstructure homogeneity and solid solution *** addition, it was found that Mg-y alloy with better comprehensive properties could be obtained by the decreasing-temperature ECAP processes. The yield strength-grain size relationship could be well described by the Hall-Petch relation for all the ECAPed Mg-y alloys,which was consistent with that the texture changes did not significantly affect the average Schmid factors of basal, prismatic and pyramidal slips for both Mg-y alloys.

关键词： Mg-RE alloy Equal channel angular pressing Texture Mechanical property

Perturbation of the Moore–Penrose Metric Generalized Inverse in Reflexive Strictly Convex Banach Spaces

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Acta Mathematica Sinica,English Series 2016年第6期32卷 725-735页

作者： Jian Bing CAO wan Qin ZHANG Postdoctoral Research Base He'nan Institute of Science and Technology Postdoctoral Research Station of Physics He'nan Normal University Department of Mathematics He'nan Institute of Science and Technology

Let X, y be reflexive strictly convex Banach spaces, let T, δT ： X → y be bounded linear operators with closed range R（T）. Put T= T ＋ δT. In this paper, by using the concept of quasiadditivity and the so called generalized Neumman lemma, we will give some error estimates of the bounds of ｜｜T^M｜｜. By using a relation between the concepts of the reduced minimum module and the gap of two subspaces, some new existence characterization of the Moore-Penrose metric generalized inverse T^M of the perturbed operator T will be also given.

关键词： Metric generalized inverse perturbation reflexive strictly convex Banach space

Fuzzy Stability of Quadratic-cubic Functional Equations

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Acta Mathematica Sinica,English Series 2011年第11期27卷 2191-2204页

作者： Zhi Hua wanG wan Xiong ZHANG Department of Mathematics Sichuan University Chengdu 610064 P. R. China School of Science Hubei University of Technology Wuhan 430068 P. R. China College of Mathematics and Statistics Chongqing University Chongqing 401331 P. R. China

In this paper, the direct method and the fixed point alternative method are implemented to give Hyers-Uiam-Rassias stability of the functional equation 6f（x＋y）-6f（x-y）＋4f（3y）=3f（x＋2y）-3f（x-2y）＋9f（2y） in fuzzy Banach spaces. We can find the range of approximate solutions obtained using the direct method are less than those obtained by using the fixed point alternative method for the above and the functional equation.

关键词： Fuzzy normed space quadratic-cubic functional equation fixed point alternative method Hyers-Ulam-Rassias stability

Exploring the sensitivity of α-decay half-life to neutron skin thickness for nuclei around ^(208)Pb

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Nuclear Science and Techniques 2017年第2期28卷 44-48页

作者： Niu wan Chang Xu Zhong-Zhou Ren Department of Physics and Key Laboratory of Modern Acoustics Institute of Acoustics Nanjing UniversityNanjing 210093 China Center of Theoretical Nuclear Physics National Laboratory of Heavy-Ion Accelerator Lanzhou 730000 China

Based on the newest experimentally extracted nuclear density distributions for double-magic nucleus208Pb(Tarbert et al. in Phys Rev Lett 112:242502, 2014),the sensitivity of α-decay half-life to nuclear skin thickness is explored in the vicinity of the shell closure region around208 Pb, i.e., isotopes of Z ? 82 and isotones of N ? *** the two-parameter Fermi(2PF) density distributions and an analytically derived formula, the α-decay half-life is found to be closely related to the magnitude of nuclear skin thickness. For a decays to the Z ? 82 isotopes, the α-decay half-life is found to decrease with the increasing neutron skin thickness, while the opposite behavior is found for a decays to the N ? 126 isotones. Therefore, it could be a possible way to extract the nuclear skin thickness from measured α-decay half-lives.

关键词： Density distribution Neutron skin thickness Density-dependent cluster model a-decay half-life

Cretaceous integrative stratigraphy and timescale of China

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Science China Earth Sciences 2019年第1期62卷 256-286页

作者： Dangpeng XI Xiaoqiao wan Guobiao LI Gang LI State Key Laboratory of Biogeology and Environmental Geology China University of Geosciences State Key Laboratory of Palaeobiology and Stratigraphy Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences

Cretaceous strata are widely distributed across China and record a variety of depositional settings. The sedimentary facies consist primarily of terrestrial, marine and interbedded marine-terrestrial deposits, of which marine and interbedded facies are relatively limited. Based a thorough review of the subdivisions and correlations of Cretaceous strata in China, we provide an up-to-date integrated chronostratigraphy and geochronologic framework of the Cretaceous system and its deposits in *** marine and interbedded marine-terrestrial sediments occur in southern Tibet, Karakorum, the western Tarim Basin,eastern Heilongjiang and Taiwan. Among these, the Himalayan area has the most complete marine deposits, the foraminiferal and ammonite biozonation of which can be correlated directly to the international standard biozones. Terrestrial deposits in central and western China consist predominantly of red, lacustrine-fluvial, clastic deposits, whereas eastern China, a volcanically active zone, contains clastic rocks in association with intermediate to acidic igneous rocks and features the most complete stratigraphic successions in northern Hebei, western Liaoning and the Songliao Basin. Here, we synthesise multiple stratigraphic concepts and charts from southern Tibet, northern Hebei to western Liaoning and the Songliao Basin to produce a comprehensive chronostratigraphic chart. Marine and terrestrial deposits are integrated, and this aids in the establishment of a comprehensive Cretaceous chronostratigraphy and temporal framework of China. Further research into the Cretaceous of China will likely focus on terrestrial deposits and mutual authentication techniques(e.g., biostratigraphy, chronostratigraphy, magnetostratigraphy and cyclostratigraphy). This study provides a more reliable temporal framework both for studying Cretaceous geological events and exploring mineral resources in China.

关键词： Cretaceous Stage/age Biostratigraphy Chronostratigraphy Magnetostratigraphy Cyclostratigraphy Stratigraphic correlation China

FATIGUE CRACK GROWTH FEATURE OF Fe-Cr-Ni MATRIX COMPOSITE REINFORCED By TITANIUM CARBIDE PARTICULATE AT 1023K

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Acta Metallurgica Sinica(English Letters) 1999年第6期12卷 0-0,0-0+0-0页

作者： Z. F. wan X.D. Hui G.Q. yuan y. S. yang X.C Chen Shandong University of Technology Jinan 250061 China Institute of Metal Research The Chinese Academy of Sciences Shenyang 110015 China Institute of Physics The Chinese Academy of Sciences Beijing 100080 China

The initiation and propagation of the short fatigue crack in a 10vol% titanium carbide particulate reichreed cast Fe-26Cr-14Ni mathe coopsite at 1023K were *** is shown that the titanium carbide particulate may hinder the crack propagation and fatigue fracture of the composite. The relationships between fatigue crack propagation rate and stress intensity factor are da/dN=4.2×10-c(△K)4 for the matrix alloy and da/dN=1.4×10-19(△K)c for the composite. The fatigue thresholds of the composite and mathe alloy are 78 and 3.2MPa.m1/2, respectively. Microcracks initiate at the intedece between titanium carbide particulate and austenite and then propagate in carkide particles. The fracture sudece of the composite shows a distinct transition from wavy and serated cleavage near the threshold regime to striation-type splitting in the stable fatigue crack propagation stage and to a veined morphology characteristic in unstable rapid region.

关键词： fatigue crack initiation and propagation Fe-Cr-Ni matrix composite titanium carbide particulate