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Zwitterionic ring-opening polymerization of macrocyclic ethyleneoxy-substituted carbonate:Access to cyclic PEG-like polycarbonate

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Chinese Chemical Letters 2024年第3期35卷 282-286页

作者： Jin huang Jinwen Li Rui Yan Yuanyuan Qu Fengzhen Guo Lei Shen Can-liang Ma Jie Sun Zhenjiang Li kai Guo State Key Laboratory of Materials-Oriented Chemical Engineering College of Biotechnology and Pharmaceutical EngineeringNanjing Tech UniversityNanjing 211816China Institute of Nanjing Advanced Biomaterials&Processing Equipment Lishui Economic Development ZoneNanjing 211299China

The innovation in polymer design to rival conventional polyethylene glycol(PEG)is an important approach to achieving a more sustainable ***,cyclic PEG-like polycarbonates having high molecular weight(4.4–49.5 kg/mol)were enabled through zwitterionic ring-opening polymerization(ZROP)of macrocyclic carbonates(MCs)mediated by N-heterocyclic carbene(NHC).The thermodynamic behavior of polymerization depends on the ring size of *** this process,the ZROP of 11-membered MC was driven by the change of enthalpy(ΔH_(p))which differed from the ZROP of 14-membered MC driven by the entropic change(ΔS_(p)).Cyclic polycarbonates depicted improved thermostability(T_(d5%)≥204℃)and higher glass transition temperatures(T_(g)>–40℃)in comparison to their linear analogues(T_(d5%)≤185℃,T_(g)~–50℃).In addition,the mechanism of ZROP of MC was addressed through computational study.A distinct mechanism of polymerization distinguishable from the well-known NHC-mediated ZROP of cyclic esters was revealed,where the zwitterion from nucleophilic addition to MC,*** intermediate,cannot be ring-opened probably due to the delocalization of negative charge on the carbonate group,but serves as an active center for the *** comparison to PEG,the attained polymer demonstrated comparable hydrophilic and biocompatible properties,as revealed by the results of contact angle and in vitro cytotoxicity studies,suggesting that cyclic polycarbonate hold the promise as the alternative of PEG.

关键词： Zwitterionic ring-opening polymerization Cyclic polycarbonate Macrocycles Tetrahedral intermediate NHC carbene

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Resonant four-photon photoemission from SnSe_(2)(001)

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Frontiers of physics 2024年第3期19卷 83-92页

作者： Chengxiang Jiao kai huang Hongli Guo Xingxia Cui Qing Yuan Cancan Lou Guangqiang Mei Chunlong Wu Nan Xu Limin Cao Min Feng School of Physics and Technology and Key Laboratory of Artificial Micro-and Nano-Structures of Ministry of Education Wuhan UniversityWuhan 430072China Department of Physics and Astronomy California State University NorthridgeNorthridgeCA 91330-8268USA Institute for Advanced Study Wuhan UniversityWuhan 430072China

High-order nonlinear multiphoton absorption is usually inefficient,but can be enhanced by designing resonant excitations between occupied and unoccupied energy *** conducted angle-resolved multi-photon photoemission(mPPE)studies on the SnSe_(2)(001)surfaces excited by ultrashort laser *** tuning photon energy and light polarization,we demonstrate the presence of a resonant four-photon photoemission(4PPE)process involving the occupied valence band(VB),the unoccupied second conduction band(CB2)and the unoccupied image-potential state(IPs)of SnSe_(2).In this 4PPE process,VB electrons of SnSe_(2) are resonantly excited into CB2 by adsorbing two photons,followed by the adsorption of another photon to populate the n=1 IPs before being emitted out to the vacuum by adsorbing one more *** results in a double-resonant 4PPE process,which exhibits approximately a 40 times enhancement in photoemission yields compared to cases where one of the resonant pathways,CB2→IPs,is inhibited by involving a virtual state instead of the IPs in the *** double-resonant 4PPE process efficiently excite the bulk VB electrons outside the vacuum,like taking advantage of resonant“ladders”through two real empty electronic states of SnSe_(2).Our results highlight the important applications of mPPE in probing the band-structure,particularly the unoccupied states,of recently emerging main group dichalcogenide ***,the discovered resonant mPPE process contributes to the exploration of their promising optoelectronic applications.

关键词： multi-photon photoemission four-photon photoemission SnSe_(2) unoccupied states resonant excitation

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Study on macro and micro shear strength of continuously graded and gap-graded sand

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Particuology 2024年第3期86卷 101-116页

作者： Peiran Zhao Songyu Liu kai Wu School of Transportation Southeast UniversityNanjing210096China

The particle gradation of sand has a significant influence on its shear strength,yet the similarities and differences between the effects of continuous and gap grading have yet to be fully *** this study,the discrete element method(DEM)was used to simulate biaxial tests on granular samples that were both continuously graded and *** macroscopic analysis revealed that the shear strength of continuously graded sands increases initially and then decreases as the uniformity of particle size distribution *** the other hand,the lack of medium particles in gap-graded sands amplifies the difference in particle size between coarse and fine particles,leading to a decrease in shear ***,both continuous and gap gradings affect the internal packing structure of the particle assembly,which consequently affects particle stress distributions,contact forces,coordination numbers,stress-induced anisotropies,and contact force networks,thus having an impact on the macroscopic shear *** global uniformity of particle size distribution was unidirectionally affected by continuous grading,while gap grading had a locally bidirectional *** findings provide a better understanding of the effects of particle grading on the macroscopic shear strength of sands.

关键词： Biaxial test Shear strength Particle gradation Discrete element method Micromechanics

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Autonomous navigation method of satellite constellation based on adaptive forgetting factors

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Chinese Journal of Aeronautics 2024年第7期37卷 317-332页

作者： Dong WANG Jing YANG kai XIONG School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China Science and Technology on Space Intelligent Control Laboratory Beijing Institute of Control EngineeringBeijing 100094China

To address the problem that model uncertainty and unknown time-varying system noise hinder the filtering accuracy of the autonomous navigation system of satellite constellation,an autonomous navigation method of satellite constellation based on the Unscented Kalman Filter with Adaptive Forgetting Factors(UKF-AFF)is *** process noise covariance matrix is estimated online with the strategy that combines covariance matching and adaptive adjustment of forgetting *** adaptive adjustment coefficient based on squared Mahalanobis distance of state residual is employed to achieve online regulation of forgetting factors,equipping this method with more *** intersatellite direction vector obtained from photographic observations is introduced to determine the constellation satellite orbit together with the distance measurement to avoid rank deficiency *** that the number of available measurements varies online with intersatellite visibility in practical applications such as time-varying constellation configurations,the smooth covariance matrix of state correction determined by innovation and gain is adopted and constructed *** analysis of the proposed method is also *** effectiveness of the proposed method is verified by the Monte Carlo simulation and comparison *** estimation accuracy of constellation position and velocity of UKF-AFF is improved by 30%and 44%respectively compared to those of the extended Kalman filter,and the method proposed is also better than other several adaptive filtering methods in the presence of significant model uncertainty.

关键词： Constellation autonomous navigation Unscented Kalman filter Adaptive forgetting factor Model uncertainty Stability analysis

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Divergent driving mechanisms of community temporal stability in China's drylands

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Environmental Science and Ecotechnology 2024年第4期20卷 237-246页

作者： kai Wang Cong Wang Bojie Fu Jianbei huang Fangli Wei Xuejing Leng Xiaoming Feng Zongshan Li Wei Jiang State Key Laboratory of Urban and Regional Ecology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing100085China College of Resources and Environment University of Chinese Academy of SciencesBeijing100049China Max Planck Institute for Biogeochemistry Hans-Kn€oll-Str.1007745JenaGermany Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing100101China Shaanxi Yan'an Forest Ecosystem National Observation and Research Station Beijing100085China National Observation and Research Station of Earth Critical Zone on the Loess Plateau in Shaanxi Xi'an710061China

Climate change and anthropogenic activities are reshaping dryland ecosystems globally at an unprecedented pace,jeopardizing their *** stability of these ecosystems is crucial for maintaining ecological balance and supporting local ***,the mechanisms governing their stability are poorly understood,largely due to the scarcity of comprehensive field *** we show the patterns of community temporal stability and its determinants across an aridity spectrum by integrating a transect survey across China's drylands with remote *** results revealed a U-shaped relationship between community temporal stability and aridity,with a pivotal shift occurring around an aridity level of *** less arid areas(aridity level below 0.88),enhanced precipitation and biodiversity were associated with increased community productivity and ***,in more arid zones(aridity level above 0.88),elevated soil organic carbon and biodiversity were linked to greater fluctuations in community productivity and reduced *** study identifies a critical aridity threshold that precipitates significant changes in community stability in China's drylands,underscoring the importance of distinct mechanisms driving ecosystem stability in varying aridity *** insights are pivotal for developing informed ecosystem management and policy strategies tailored to the unique challenges of dryland conservation.

关键词： Dryland ecosystems Community stability Ecosystem management Species richness Aridity threshold

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Robustness of the octupole collectivity in 144Ba within the cranking covariant density functional theory in 3D lattice

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Nuclear Science and Techniques 2024年第8期35卷 124-131页

作者： Ze‑kai Li Yuan‑Yuan Wang Mathematics and Physics Department North China Electric Power UniversityBeijing 102206China Hebei Key Laboratory of Physics and Energy Technology North China Electric Power UniversityBaoding 071000China

The octupole deformation and collectivity in octupole double-magic nucleus 144Ba are investigated using the Cranking covariant density functional theory in a three-dimensional lattice *** reduced B(E3)transition probability is implemented for the first time in semiclassical approximation based on the microscopically calculated electric octupole *** available data,including the I-ωrelation and electric transitional probabilities B(E2)and B(E3)are well ***,it is shown that the ground state of 144Ba exhibits axial octupole and quadrupole deformations that persist up to high spins(I≈24h).

关键词： Octupole collectivity Cranking covariant density functional theory Rotational spectrum Electric transitional probabilities

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Impact of the Political Risk on Food Reserve Ratio:Evidence Across Countries

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Journal of Systems Science & Complexity 2024年第5期37卷 2071-2103页

作者： XING kai LI Shang YANG Xiaoguang School of Economics&Management Nanchang University Department of Statistics and Data Science National University of Singapore Academy of Mathematics and Systems Science Chinese Academy of Sciences University of Chinese Academy of Sciences

Using an unbalanced panel data covering 75 countries from 1991 to 2019, the authors explore how the political risk impacts on food reserve ratio. The empirical findings show that an increasing political risk negatively affects food reserve ratio, and the same effects hold for both internal risk and external risk. Moreover, the authors find that the increasing external or internal risks both negatively affect food production and food exports, but external risk does not significantly impact food imports and it positively impacts food consumption, while internal risk negatively impacts food imports and food consumption. The results suggest that most governments have difficulty raising subsequent food reserve ratios in face of an increasing political risk, no matter if it is an internal risk or an external risk although the mechanisms behind the impacts are different.

关键词： External risk food reserve ratio internal risk political risk

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Progress and prospects of graphene-based materials in lithium batteries

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Rare Metals 2024年第5期43卷 1886-1905页

作者： Shen Lai Tao huang Pei Liu Hong-Bin Wang Shi-Chun Yang Xin-Hua Liu kai Yang Qian-Ling Zhang Jian-Hong Liu Jiang-Tao Hu Graphene Composite Research Center College of Chemistry and Environmental EngineeringShenzhen UniversityShenzhen 518060China College of Physics and Optoelectronic Engineering Shenzhen UniversityShenzhen 518060China Shenzhen Eigen-Equation Graphene Technology Co.Ltd Shenzhen518060China School of Transportation Science and Engineering Beihang UniversityBeijing 100191China Department of Electrical and Electronic Engineering Advanced Technology InstituteUniversity of SurreyGuildfordSurrey GU27XHUK

Reasonable design and applications of graphene-based materials are supposed to be promising ways to tackle many fundamental problems emerging in lithium batteries,including suppression of electrode/electrolyte side reactions,stabilization of electrode architecture,and improvement of conductive ***,extensive fundamental research on this aspect has been performed so ***,when it comes to large-scale industrial applications,the utilization of graphene-based materials progresses at a very slow ***,there presents a severe technological decoupling between academic research and industrial application,and there is an urgent need to link ***,in order to address current issues of graphene-based materials used in lithium batteries,we present their latest advancements with stateof-the-art *** applications of graphenebased materials in practical lithium batteries are highlighted and predicted to bridge the gap between the academic progress and industrial manufacture,thereby paving the way for accelerating the development of graphenebased material as well as lithium battery industry.

关键词： Lithium batteries Graphene-based materials Academic research Industrial application Development direction

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Emerging role of exosomes in ulcerative colitis: Targeting NOD-like receptor family pyrin domain containing 3 inflammasome

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World Journal of Gastroenterology 2024年第6期30卷 527-541页

作者： Xin Li Li-Jiang Ji kai-Di Feng Hua huang Mei-Rou Liang Shi-Jin Cheng Xiu-Dong Meng School of Basic Medicine Guizhou University of Traditional Chinese MedicineGuiyang 550025Guizhou ProvinceChina Department of Anorectal Surgery Changshu Hospital Affiliated to Nanjing University of Chinese MedicineChangshu 215500Jiangsu ProvinceChina College of Traditional Chinese Medicine Tianjin University of Traditional Chinese MedicineTianjin 301617China

Ulcerative colitis(UC)is a chronic recurrent inflammatory bowel *** ongoing advances in our understanding of UC,its pathogenesis is yet unelu-cidated,underscoring the urgent need for novel treatment strategies for patients with *** are nanoscale membrane particles that mediate intercellular communication by carrying various bioactive molecules,such as proteins,RNAs,DNA,and *** NOD-like receptor family pyrin domain containing 3(NLRP3)inflammasome is a cytosolic tripartite protein complex whose activation induces the maturation and secretion of proinflammatory cytokines interleukin-1β(IL-1β)and IL-18,triggering the inflammatory response to a pathogenic agent or *** evidence suggests that exosomes are new modulators of the NLRP3 inflammasome,with vital roles in the pathological process of ***,recent evidence is reviewed on the role of exosomes and NLRP3 inflammasome in ***,the dual role of exosomes on NLRP3 inflammasome and the effect of NLRP3 inflammasome on exosome secretion are ***,an outlook on the directions of exosome-NLRP3 inflammasome crosstalk research in the context of UC is proposed and areas of further research on this topic are high-lighted.

关键词： Ulcerative colitis Exosomes Inflammasome Evidence Therapeutics

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Comprehensive evaluation framework for intervention on health effects of ambient temperature

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Eco-Environment & Health 2024年第2期3卷 154-164页

作者： Jiaming Wang Peng Wang Beibei Liu Patrick L.Kinney Lei huang kai Chen State Key Laboratory of Pollution Control and Resource Reuse School of the EnvironmentNanjing UniversityNanjing 210023China Faculty of Civil Engineering and Mechanics Jiangsu UniversityZhenjiang 212013China Department of Environmental Health Boston University School of Public HealthBostonMA 02118USA Center for Public Health Research Medical School of Nanjing UniversityNanjing 210093China Department of Environmental Health Sciences Yale Center on Climate Change and HealthYale School of Public HealthNew HavenCT 06510USA

Despite the existence of many interventions to mitigate or adapt to the health effects of climate change,their effectiveness remains ***,we introduce the Comprehensive Evaluation Framework for Intervention on Health Effects of Ambient Temperature to evaluate study designs and effects of intervention *** framework comprises three types of interventions:proactive,indirect,and direct,and four categories of indicators:classification,methods,scope,and *** trialed the framework by an evaluation of existing intervention *** evaluation revealed that each intervention has its own applicable characteristics in terms of effectiveness,feasibility,and generalizability *** expanded the framework's potential by offering a list of intervention recommendations in different *** applications are then explored to establish models of the relationship between study designs and intervention effects,facilitating effective interventions to address the health effects of ambient temperature under climate change.

关键词： Intervention Evaluation framework Ambient temperature Climate change Human health Evaluation practice

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