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The Moduli Space of Stable Coherent Sheaves via Non-archimedean Geometry

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Acta Mathematica Sinica,English Series 2022年第10期38卷 1722-1780页

作者： yun Feng jiang Department of Mathematics University of Kansas405 Snow Hall1460 Jayhawk BlvdLawrence USA

We provide a construction of the moduli space of stable coherent sheaves in the world of non-archimedean geometry,where we use the notion of Berkovich non-archimedean analytic spaces.The motivation for our construction is Tony Yue Yu’s non-archimedean enumerative geometry in Gromov-Witten theory.The construction of the moduli space of stable sheaves using Berkovich analytic spaces will give rise to the non-archimedean version of Donaldson-Thomas invariants.In this paper we give the moduli construction over a non-archimedean field K.We use the machinery of formal schemes,that is,we define and construct the formal moduli stack of(semi)-stable coherent sheaves over a discrete valuation ring R,and taking generic fiber we get the non-archimedean analytic moduli space of semistable coherent sheaves over the fractional non-archimedean field K.We generalize Joyce’s dcritical scheme structure in[37]or Kiem-Li’s virtual critical manifolds in[38]to the world of formal schemes,and Berkovich non-archimedean analytic spaces.As an application,we provide a proof for the motivic localization formula for a d-critical non-archimedean K-analytic space using global motive of vanishing cycles and motivic integration on oriented formal d-critical schemes.This generalizes Maulik’s motivic localization formula for the motivic Donaldson-Thomas invariants.

关键词： Non-archimedean Donaldson-Thomas theory Berkovich space analytic d-critical scheme motivic localization

Tension-compression asymmetry and corresponding deformation mechanism in ZA21 magnesium bars with bimodal structure

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International Journal of Minerals,Metallurgy and Materials 2023年第1期30卷 92-103页

作者： Yujiao Wang yun Zhang Haitao jiang Institute of Engineering Technology University of Science and Technology BeijingBeijing 100083China Beijing Institute of Machinery and Equipment Beijing 100854China

We investigated the asymmetric tension-compression(T-C)behavior of ZA21 bars with bimodal and uniform structures through axial tension and compression tests.The results show that the yield strengths of bars having bimodal structure are 206.42 and 140.28 MPa under tension and compression,respectively,which are higher than those of bars having uniform structure with tensile and compressive yield strength of 183.71 and 102.86 MPa,respectively.Prismatic slip and extension twinning under tension and basal slip and extension twinning under compression dominate the yield behavior and induce the T-C asymmetry.However,due to the basal slip activated in fine grains under tension and the inhibition of extension twinning by fine grains under compression,the bimodal structure possesses a lower T-C asymmetry(0.68)compared to the uniform structure(0.56).Multiple extension twins occur during deformation,and the selection of twin variants depends on the Schmid factor of the six variants activated by parent grains.Furthermore,the strengthening effect of the bimodal structure depends on the grain size and the ratio of coarse and fine grains.

关键词： bimodal structure deformation mechanism Hall-Petch relationship tension-compression asymmetry twin variant selection

Kobayashi’s and Teichmuller’s Metrics and Bers Complex Manifold Structure on Circle Diffeomorphisms

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Acta Mathematica Sinica,English Series 2020年第3期36卷 245-272页

作者： yun Ping jiang Department of Mathematics Queens College of the City University of New York FlushingNY 11367-1597USA Department of Mathematics Graduate School of the City University of New York365 Fifth A venueNew YorkNY 10016USA

Given a modulus of continuity ω,we consider the Teichmuller space TC1+ω as the space of all orientation-preserving circle diffeomorphisms whose derivatives are ω-continuous functions modulo the space of Mobius transformations preserving the unit disk.We study several distortion properties for diffeomorphisms and quasisymmetric homeomorphisms.Using these distortion properties,we give the Bers complex manifold structure on the Teichm(u| ")ller space TC^1+H as the union of over all0 <α≤1,which turns out to be the largest space in the Teichmuller space of C1 orientation-preserving circle diffeomorphisms on which we can assign such a structure.Furthermore,we prove that with the Bers complex manifold structure on TC^1+H ,Kobayashi’s metric and Teichmuller’s metric coincide.

关键词： Bers complex manifold structure circle diffeomorphism modulus of continuity quasisymmetric circle homeomorphism Teichmuller space Kobayashi's metric Teichmuller's metric

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大而显著的苞片影响了笋兰的繁殖成功

Journal of Plant Ecology 2024年第1期17卷 50-56页

作者： Shi-Mao Wu jiang-yun Gao Institute of Biodiversity School of Ecology and Environmental ScienceYunnan UniversityKunmingYunnan 650500China

在被子植物中,多样的花部特征是为了适应各种选择压力和生态功能。到目前为止,对兰科植物花部特征的生态功能研究主要集中在唇瓣,而从未有对苞片的研究。本研究以一种熊蜂授粉并且提供花蜜报酬的地生或附生兰科植物笋兰(Thunia alba)为... 详细信息

在被子植物中,多样的花部特征是为了适应各种选择压力和生态功能。到目前为止,对兰科植物花部特征的生态功能研究主要集中在唇瓣,而从未有对苞片的研究。本研究以一种熊蜂授粉并且提供花蜜报酬的地生或附生兰科植物笋兰(Thunia alba)为研究材料,其大而显著形似舟状的苞片包裹着花蜜距和花梗。我们猜想显著的大苞片能够保护蜜距,抵御盗蜜者。为了验证这一假设,我们通过实验去除苞片,记录传粉者和盗蜜者访花行为的变化,并评估了它们对笋兰繁殖成功的影响。研究结果表明,当苞片被去除后,唯一的传粉者短头熊蜂(Bombus breviceps)转变为盗蜜者,并且被盗蜜的花的比例也显著增加。无论是花苞片被去除的处理组还是未处理的对照组,笋兰都是受传粉者限制的。去除苞片对传粉者的访花频率并没有影响,但是显著降低了笋兰雄性和雌性的繁殖成功率。本研究表明,在复杂的授粉限制的环境压力下,大而显著的苞片可以防止花被盗蜜者盗蜜从而提高笋兰的整体适合度。

关键词：苞片传粉者盗蜜繁殖成功笋兰(Thunia alba) 短头熊蜂(Bombus breviceps)

KREEP-rich breccia in Chang'E-5 regolith and its implications

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Science China Earth Sciences 2023年第11期66卷 2473-2486页

作者： Aoxin MEI Yun Jiang Shiyong LIAO Jinting KANG Fang HUANG Weibiao HSU CAS Key Laboratory of Planetary Sciences Purple Mountain ObservatoryChinese Academy of SciencesNanjing 210023China School of Astronomy and Space Sciences University of Science and Technology of ChinaHefei 230026China Center for Excellence in Comparative Planetology Chinese Academy of SciencesHefei 230026China CAS Key Laboratory of Crust-Mantle Materials and Environments School of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei 230026China Institute of Deep Space Sciences Deep Space Exploration LaboratoryHefei 230026China

Lunar breccias provide crucial insights into the lithological diversity,shock processing and evolution of the lunar crust.Here,we report a unique regolith breccia(CE5C0000YJYX070GP,hereafter CE5C)returned from the Chang'E-5(CE-5)mission.CE5C is one of the largest CE-5 breccias with a wide variety of lithologies,dominated by basaltic and mineral fragments as well as impact-melted clasts(including mid-Ti glasses,high-Al glasses,and crystal-bearing impact melt clasts).A comprehensive study of petrology and mineralogy on several representative clasts was conducted by integrating Scanning Electron Microscopy(SEM),Tescan Integrated Mineral Analysis(TIMA),Electron Probe Microanalysis(EPMA)and Laser Ablation Inductively Coupled Plasma Mass Spectrometry(LA-ICP-MS)techniques.Evidence is sufficient that CE5C is a mixed mare-highland regolith breccia,with a high percentage of KREEPy material(>20 vol.%),which has not been previously reported in other CE-5 samples.The mid-Ti impact glasses are characterized by high FeO(24.0 wt.%)and intermediate TiO_(2)(5.5 wt.%)contents,while the high-Al impact glasses have a chemical composition compatible with KREEP.Integrated with the regional geological context of the CE-5 landing site,we propose that CE5C is likely derived from a mixed region between the P58/Em4 mare unit and its contiguous eastern highlands.Despite the difficulty in assessing the representativeness of CE5C,the substantial presence of KREEPy material may provide valuable clues to the provenance of exotic ejecta,including the identification of unrecognized source craters situated in the eastern periphery of the sampling unit.

关键词： Chang'E-5 Regolith breccia Impact glasses KREEP Mare basalts

Political uncertainty,leadership and productivity

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Economic and Political Studies 2022年第3期10卷 314-326页

作者： Chunxia jiang yun Zhu Business School University of AberdeenAberdeenUK The Peter J.Tobin College of Business St.John’s UniversityQueensNYUSA

We investigate the impact of political uncertainty in the context of the upper echelon theory.Using provincial-level data of polit-ical leaders in China over the period 1995–2015,we take a two-step approach to first examine the impact of top leader teams’(TLTs)traits on productivity and,second,to test if such leadership effects vary with political uncertainty.We find that TLTs’educa-tion,generally a driving force behind productivity,is less effective during the period of high political uncertainty.TLTs’work experi-ence positively contributes to productivity,which is strengthened under high political uncertainty.TLTs’career ambition leads to higher productivity,but such an effect attenuates when political uncertainty is high.Finally,TLTs’political positions negatively con-tribute to productivity and the effect is barely affected by political uncertainty,suggesting a disconnection between political posi-tions and economic outcomes.

关键词： Political uncertainty leadership productivity

Transcriptome analysis reveals the mechanism of chronic heat stress on meat quality of broilers

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Journal of Animal Science and Biotechnology 2023年第1期14卷 409-422页

作者： Zhen Liu Yingsen Liu Tong Xing Jiaolong Li Lin Zhang Yun Jiang Feng Gao College of Animal Science and Technology Key Laboratory of Animal Origin Food Production and Safety Guarantee of Jiangsu ProvinceJiangsu Collaborative Innovation Center of Meat Production and ProcessingQuality and Safety ControlNanjing Agricultural UniversityNo.1 WeigangWeigang 210095 NanjingChina. Institute of Agri‑Products Processing Jiangsu Academy of Agricultural SciencesNanjing 210014People’s Republic of China. School of Food Science and Pharmaceutical Engineering Nanjing Normal UniversityNanjing 210023People’s Republic of China.

Background:Chronic heat stress has a negative impact on poultry meat quality.Although this has been extensively investigated,previous studies have primarily focused on metabolic alterations and oxidative stress in the pectoralis major(PM)muscle under chronic heat stress,and not all of the underlying molecular mechanisms are completely understood.Methods:A total of 144 male Arbor Acres broilers(28 d old)were randomly allocated into 3 treatment groups:(1)the normal control(NC)group,with broilers raised at 22℃and fed a basal diet;(2)the heat stress(HS)group,with birds raised at 32℃and fed a basal diet;and(3)the pair-fed(PF)group,with birds raised at 22℃and fed the amount of feed equal to the feed consumed on the previous day by the HS group.The experiment lasted for 14 d.Results:Chronic heat stress decreased the average daily feed intake and average daily gain,increased feed:gain ratio(P<0.05);and increased drip loss,cooking loss,shear force,hardness,and decreased p H,redness(a*);and springiness of PM muscle(P<0.05).Furthermore,chronic heat stress decreased muscle fiber density,increased connective tissue,and led to intracellular vacuolation.The transcriptome analyses indicated that the effect of chronic heat stress on meat quality was not only related to metabolism and oxidative stress,but also to signal transduction,immune system,transport and catabolism,cell growth and death,and muscle structure.Conclusions:Chronic heat stress has a negative impact on the growth performance,meat quality,and the PM muscle structure of broilers.Transcriptome analysis revealed a comprehensive understanding of the mechanism of the chronic heat stress-induced deterioration of broiler meat quality at the transcriptional level.

关键词： Chronic heat stress Meat quality Transcriptome

Assembly of peptide nanostructures with controllable sizes

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Nano Research 2024年第1期17卷 151-161页

作者： Dan Cheng Fan Jia yun-Bao jiang Vincent P.Conticello Tao jiang The MOE Key Laboratory of Spectrochemical Analysis and Instrumentation Department of ChemistryCollege of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province(IKKEM) Xiamen 361005China Department of Chemistry Emory UniversityAtlanta 30033USA

Controlled peptide assembly offers significant promise to develop synthetic supramolecular nanostructures to display material and biological properties that mimic protein assemblies in nature.Despite the progress in forming peptide nanostructures of various morphology,there exists a distinct gap between natural and synthetic assembly systems in terms of size control.Constructing nanostructures with a narrow size distribution that can be tuned over a wide range of length-scales is essential for applications that require precise spacing between objects.This approach provides the opportunity to correlate materials and biological properties of interest with assembly size.In this review,we discuss representative endeavors over the past two decades for design of size-controllable peptide nanostructures using tunable building blocks.Other mechanisms for size control,e.g.,molecular frustration,template-directed peptide assembly,and multi-component peptide co-assembly,will also be discussed.We also demonstrate the applicable scopes of these strategies and suggest potential future avenues for scientific advances in this field.

关键词： peptide assembly controllable size template multi-component

Microwave absorption properties of Ni/C@SiC composites prepared by precursor impregnation and pyrolysis processes

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Defence Technology（防务技术） 2023年第3期21卷 94-102页

作者： Xinli Ye Junxiong Zhang Zhaofeng Chen Junfeng Xiang Yun Jiang Faqin Xie Xiaomin Ma School of Civil Aviation Northwestern Polytechnical UniversityXi'an710072PR China Suzhou Qinyun Fiber Assemblies Technology Co.LTD Suzhou215400PR China School of Textile and Clothing Nantong UniversityNantong226019PR China College of Materials Science and Technology Nanjing University of Aeronautics and AstronauticsNanjing211106PR China College of Textile Science and Engineering Jiangnan UniversityWuxi214122PR China National Equipment New Material&Technology(jiangsu)Co.LTD Suzhou215400PR China

In the present study,the unique three-dimensional graphene coated nickel(Ni/C)foam reinforced silicon carbide(Ni/C@SiC)composites were first obtained via the precursor impregnation and pyrolysis(PIP)processes.The microstructure images indicated that the SiC fillers were successfully prepared in the skeleton pores of the Ni/C foam.The influence of the PIP cycles on the microwave absorption performances was researched,and the results indicated that after the primary PIP process,Ni/C@SiC-I possessed the optimal microwave absorbing performance with a minimum reflection loss(RL)of-25.87 d B at 5.28 GHz and 5.00 mm.Besides,the RL values could be below-10.00 dB from 5.88 GHz to 7.74 GHz when the corresponding matching thickness was 3.85 mm.However,the microwave absorption properties of Ni/C@SiC-II and Ni/C@SiC-Ⅲwere tremendously degraded as the PIP times increased.At last,the electromagnetic parameter,dielectric loss,attenuation constant as well as impedance matching coefficient were further investigated to analyze the absorbing mechanism,which opened a new path for the certain scientific evaluation of the absorbing materials and had extremely important to the defence technology.

关键词： composites Ni/C absorption