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Science China Chemistry 2024年第7期67卷 2306-2313页

作者： Dong-yue Cai Weiming Shi Zhao-Hui Jin Zhi-Xiang Yu Jin-Xin Zhao jian.min yue State Key Laboratory of Drug Research Shanghai Institute of Materia MedicaChinese Academy of SciencesShanghai 201203China University of Chinese Academy of Sciences Beijing 100049China Beijing National Laboratory for Molecular Sciences(BNLMS) Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of EducationCollege of ChemistryPeking UniversityBeijing 100871China

Mimicking biosynthetic pathways of hongkonoids led to the development of a new Cu(Ⅰ)-catalyzed[3+2]cycloaddition ofα-hydroxyketone andβ-keto enol ethers,affording tetrahydrofuran acetals in a highly diastereoselective manner and 100%atom *** studies on the mechanism disclosed a concerted but asynchronous Michael addition/aldol *** the same importance,this methodology provides a practical biomimetic approach for one-step construction of the dibenzylbutyrolactol lignan backbone starting from two phenyl propane derivatives,opening up a powerful new approach for lignan synthesis,which is showcased by succinct total syntheses of two biologically important aryltetralin-type lignans,β-apopicropodophyllin and *** the mild and operationally simple conditions,the developed chemistry might have a promising prospect in potential industrial applications.

关键词： [3+2]cycloaddition transition-metal catalysis tetrahydrofuran lignans natural products

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Universal method for designing periodic orbits by homotopy classes in the elliptic restricted three-body problem

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Astrodynamics 2024年第1期8卷 175-188页

作者： yue Zheng min Zhao School of Electronic Engineering Xi’an Aeronautical InstituteXi’an710077China School of Aircraft Engineering Xi’an Aeronautical InstituteXi’an710077China School of Astronautics Northwestern Polytechnical UniversityXi’an710072China

The current methods for designing periodic orbits in the elliptic restricted three-body problem(ERTBP)have the disadvantages of targeting limited orbits and ergodic searches and considering only symmetric orbits.A universal method for designing periodic orbits is proposed in this ***,the homotopy classes of orbits are structured based on their topological ***,a dynamic model based on homotopy classes,ranging from the circular restricted three-body problem(CRTBP)to the ERTBP,can be built using the homotopy ***,a multi-and a single-period orbit were selected based on the resonance ***,the corresponding orbit in the ERTBP was computed by modifying the initial condition of the orbit in the *** method,without an ergodic search,can extend to any orbit,including an asymmetric orbit in the CRTBP,to the ERTBP model,and the two orbits are of the same homotopy *** of the Earth–Moon ERTBP are presented to verify the efficiency of this method.

关键词： periodic orbit elliptic restricted three-body problem(ERTBP) topology homotopy circular restricted three-body problem(CRTBP)

Multicolored Bipartite Ramsey Numbers of Large Cycles

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Acta Mathematicae Applicatae Sinica 2024年第2期40卷 347-357页

作者： Shao-qiang LIU yue-jian PENG College of Mathematics and Statistics Hanshan Normal UniversityChaozhou 521041China School of Mathematics Hunan UniversityChangsha 410082China

For an integer r≥2 and bipartite graphs Hi,where 1≤i≤r,the bipartite Ramsey number br(H1,H2,…,Hr)is the minimum integer N such that any r-edge coloring of the complete bipartite graph KN;N contains a monochromatic subgraph isomorphic to Hi in color i for some 1≤i≤*** show that if r≥3;α1,α2>0,αj+2≥[(j+2)!-1]Σi=1^(j+1)α1 for j=1,2…r-2,then br(C2[α1n],C2[α2n],…,C2[αrn]=(Σ=j=1^(r)a j+o(1))n.

关键词： ramsey number bipartite ramsey number regularity lemma

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Large post-liquefaction deformation of sand:Mechanisms and modeling considering water absorption in shearing and seismic wave conditions

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Underground Space 2024年第5期18卷 3-64页

作者： jian.min Zhang Rui Wang Department of Hydraulic Engineering State Key Laboratory of Hydroscience and EngineeringTsinghua UniversityBeijing 100084China

Large deformation of sand due to soil liquefaction is a major cause for seismic *** this study,the mechanisms and modeling of large post-liquefaction deformation of sand considering the significant influence of water absorption in shearing and seismic wave *** of case histories from past earthquakes and review of existing studies highlight the importance of the two *** on the micro and macro scale mechanisms for post-liquefaction shear deformation,the mechanism for water absorption in shearing after initial liquefaction is *** is aided by novel designed constant water-absorption-rate shear *** absorption in shearing can be classified into three types,including partial water absorption,complete water absorption,and compulsory water *** the influence of water absorption in shearing,even a strongly dilative sand under naturally drained conditions could experience instability and large shear *** mechanism for amplification of post-liquefaction deformation under surface wave load is also explained via element tests and theoretical *** shows that surface wave–shear wave coupling can induce asymmetrical force and resistance in sand,resulting in asymmetrical accumulation of deformation,which is amplified by liquefaction.A constitutive model,referred to as CycLiq,is formulated to capture the large deformation of sand considering water absorption in shearing and seismic wave conditions,along with its numerical implementation *** model is comprehensively calibrated based on various types of element tests and validated against centrifuge shaking table tests in the liquefaction experiments and analysis projects(LEAP).The model,along with various numerical analysis methods,is adopted in the successful simulation of water absorption in shearing and Rayleigh wave-shear wave coupling induced large liquefaction ***,the model is applied to high-performance simulation fo

关键词： Liquefaction Sand Large deformation Water absorption in shearing Surface wave Rayleigh wave-shear wave coupling

Highly Aromatic Norditerpenoid Heterodimers and Monomers from Trigonostemon fragilis

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Engineering 2024年第7期38卷 144-154页

作者： Jun-Su Zhou Long Cheng Yuan Gao Zhan-Peng Ge Bin Zhou Jing-Ya Li Jin-Xin Zhao jian.min yue State Key Laboratory of Drug Research Shanghai Institute of Materia MedicaChinese Academy of SciencesShanghai 201203China Shandong Laboratory of Yantai Drug Discovery Bohai Rim Advanced Research Institute for Drug DiscoveryYantai 264117China

Four new norditerpenoid heterodimers with different dimerization patterns-namely,trigofragiloids A-C(denoted as compounds 1-3)and(+)-and(-)-trigofragiloid D(compound 4)-and three new phenanthrenone norditerpenoids-namely,trigofragiloids E-G(compounds 5-7)-were isolated from Trigonostemon *** 1 and 2 feature a novel heterodimeric carbon skeleton formed by the conjugation of a tetra-norditerpenoid and an ennea-norditerpenoid;they have been identified as class 2 atropisomers by means of quantum chemical *** 3 is an unprecedented phenylpropanoid-norditerpenoid adduct with a new dimerization ***(+)-and(-)-4 are the first example of S-shaped 1,4-dioxane-fused norditerpenoid *** by the structure elucidation of compound 4,two co-occurring analogues,actephilol A and epiactephilol A,were structurally revised as a pair of geometrical isomers and were identified as two pairs of enantiomers,(+)-and(-)-8 and(+)-and(-)-9,*** structures were characterized using a combined ***,compound 7 exhibits remarkable adenosine triphosphate-citrate lyase(ACLY)inhibition with a halfmaximal inhibition concentration(IC50)value of(0.46±0.11)lmol·L^(-1),as active as the positive control BMS-303141,and a molecular docking study offers deep insight into the interaction between compound 7 and ACLY.

关键词： Norditerpenoid heterodimer Trigonostemon fragilis Euphorbiaceae Trigofragiloid Structural revision Adenosine triphosphate-citrate lyase(ACLY) inhibitory activity

Suppression of the regrowth interface leakage current in AlGaN/GaN HEMTs by Fe doped GaN substrate

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Science China(Information Sciences) 2024年第6期67卷 461-462页

作者： Xiao WANG Zhi-Yu LIN Yuan-Hang SUN Long yue Yu-min ZHANG jian-Feng WANG Ke XU School of Nano-Tech and Nano-Bionics University of Science and Technology of China Suzhou Institute of Nano-tech and Nano-bionics Chinese Academy of Sciences Information Materials Research Department Suzhou laboratory Suzhou Nanowin Science and Technology Co. Ltd. jiangsu Institute of Advanced Semiconductors

In the process of homoepitaxy AlGaN/GaN heterojunction by metal-organic chemical vapor deposition (MOCVD) on free-standing substrates,Si impurities from the air and reaction chamber accumulate at the regrowth interfac...

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Comprehensive tensile properties improved by deep cryogenic treatment prior to aging in friction-stir-welded 2198 Al–Li alloy

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Rare Metals 2024年第10期43卷 5403-5409页

作者： jian-Qiu Sun yue Ma Chong Gao Hong-Yun Luo School of Materials Science and Engineering Beihang University Chinalco Research Institute of Science and Technology

In order to improve the comprehensive mechanical properties,deep cryogenic treatment （DCT）prior to aging was carried out on friction-stir-welded（FSW） 2198 Al-Li alloy;afterward,the microstructure and tensile properties were characterized by means of optical microscopy （OM）,transmission electron microscopy（TEM） and tensile *** results show that FSW 2198 alloy through DCT prior to aging （DAT） possesses superior tensile properties than conventional aging treatment （AT）The microstructural analysis reveals that DAT alloy exhibits a finer grain structure,since DCT might effectively alleviate the residual stress in FSW 2198 alloy and thus decrease the driving force for grain coarsening in subsequent aging ***,DCT generates dislocation multiplication,which provides more preferential nucleation sites for T1 （Al2CuLi） phase during subsequent aging treatment,resulting in high-density fine T1 phases and thin precipitate-free zone within DAT *** reasonable microstructure leads to DAT alloy possessing better strength-ductility combination compared to AT alloy.

关键词： Al–Li alloy Deep cryogenic treatment Friction stir welding Tensile properties

From molecule to cell:the expanding frontiers of plant immunity

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Journal of Genetics and Genomics 2024年第7期51卷 680-690页

作者： Lei Li Jing Liu jian.min Zhou Key Laboratory of Seed Innovation Institute of Genetics and Developmental BiologyChinese Academy of SciencesBeijing 100101China Hainan Yazhou Bay Seed Laboratory SanyaHainan 572025China

In recent years,the field of plant immunity has witnessed remarkable *** the co-evolution between plants and pathogens,plants have developed a wealth of intricate defense mechanisms to safeguard their *** identified immune receptors have added unexpected complexity to the surface and intracellular sensor networks,enriching our understanding of the ongoing plant–pathogen *** the molecular mechanisms of resistosome shapes our understanding of these mysterious molecules in plant ***,technological innovations are expanding the horizon of the plant–pathogen battlefield into spatial and temporal *** the development provides new opportunities for untangling the complex realm of plant immunity,challenges remain in uncovering plant immunity across spatiotemporal dimensions from both molecular and cellular levels.

关键词： Plant immunity Calcium Spatiotemporal Biomolecular condensate Immune receptor Resistosome

Ramsey Numbers of Trees Versus Multiple Copies of Books

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Acta Mathematicae Applicatae Sinica 2024年第3期40卷 600-612页

作者： Xiao-bing GUO Si-nan HU yue-jian PENG School of Mathematical Sciences Luoyang Normal UniversityLuoyang 471934China School of Mathematics Hunan UniversityChangsha 410082China

Given two graphs G and H,the Ramsey number R(G,H) is the minimum integer N such that any two-coloring of the edges of K_(N) in red or blue yields a red G or a blue *** v(G) be the number of vertices of G and χ(G) be the chromatic number of *** s(G) denote the chromatic surplus of G,the number of vertices in a minimum color class among all proper χ(G)-colorings of *** showed that R(G,H)≥(v(G)-1)(χ(H)-1)+s(H) if G is connected and v(G)≥s(H).A connected graph G is H-good if R(G,H)=(v(G)-1)(χ(H)-1)+s(H).Let tH denote the disjoint union of t copies of graph H,and let G∨H denote the join of G and *** a complete graph on n vertices by K_(n),and a tree on n vertices by T_(n).Denote a book with n pages by B_(n),i.e.,the join K_(2) ∨■.Erd?s,Faudree,Rousseau and Schelp proved that T_(n) is B_(m)-good if n≥*** this paper,we obtain the exact Ramsey number of T_(n) versus 2B_(2).Our result implies that T_(n) is 2B_(2)-good if n≥5.

关键词： ramsey number ramsey goodness tree book

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Effect of Cr_(2)O_(3) on properties of CaO-SiO_(2)-Fe_(t)O-MgO system and dissolution behavior of lime

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Journal of Iron and Steel Research International 2024年第4期31卷 870-881页

作者： Shan-nan Li jian-li Li yue Yu Hang-yu Zhu The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina Hubei Provincial Key Laboratory for New Processes of Ironmaking and Steelmaking Wuhan University of Science and TechnologyWuhan 430081HubeiChina Key Laboratory for Ferrous Metallurgy and Resources Utilization of ministry of Education Wuhan University of Science and TechnologyWuhan 430081HubeiChina

The productivity of the chrome-containing semi-steel converter smelting process is directly affected by the slag-forming speed during the converter preliminary *** effects of Cr_(2)O_(3) content on the physicochemical properties of the CaO-SiO_(2)-Fe_(t)O-MgO system,such as melting temperature,solidification behavior,mineral composition,and lime dissolution rate,were *** results showed that the slag was an amorphous phase at 1500℃.When Cr_(2)O_(3) was added,Ca(Fe,Mg)Si_(2)O_(6) and spinel were formed in the *** the increase in Cr_(2)O_(3) content,the amount of spinel precipitation increased,and the dendritic FegO_(4) crystal gradually changed into the granular(Fe,Mg)(Fe,Cr)2O_(4) *** the Cr_(2)O_(3) content increased from O to 2.91 wt.%,the melting temperature of the slag rose,and the melting range of the slag expanded slightly,but the lime dissolution rate did not *** the Cr_(2)O_(3) content further increased to 9.09 wt.%,the melting temperature continued to rise,the melting range rapidly expanded,and the lime dissolution rate decreased.

关键词： Cr_(2)O_(3) Vanadium-titanium magnetite Converter Slag Lime dissolution