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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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Decomposition of pre-existing Au–p clusters induced in situ a-Fe grains uniformization in Fe–p-based nanocrystalline alloys

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Rare Metals 2024年第10期43卷 5242-5255页

作者： Min-Hao Han Cheng Sun guo-guo Xi Yang Meng Qiang Luo Xue-Qian Yu Wen-Feng Zhang Hao Liu Hong-Jie Xu Tao Zhang Key Laboratory of Aerospace Materials and performance(Ministry of Education) School of Materials Science and EngineeringBeihang University Laboratory of Functional Fiber Materials Institute of Bast Fiber CropsChinese Academy of Agricultural Science School of Materials Science and Engineering Jiangsu Key Laboratory for Advanced Metallic MaterialsSoutheast University Institute for Advanced Materials North China Electric Power University Center for Advanced Analysis and Computational Science Zhengzhou University

In Fe-based amorphous-/nanocrystalline ribbons,the uniformization and refinement of a-Fe grains are key aspects for optimizing their soft magnetic and mechanical ***,the Fe–p–C–B nanocrystalline alloy system was selected for *** produced as-spun ribbons with pre-existing nanocrystals through melt-quenching and then obtained a well-distributed a-Fe nanocrystalline structure through annealing below the first crystallization onset temperature （633 K）resulting in excellent magnetic properties (saturation magnetization of 1.65 T and coercivity of 1.6 A·m-1)ultra-wide annealing temperature window （from 613 to 733 K）,and extremely high annealing stability （up to 480 min at 633 K）.Furthermore,we propose a new in situ two-step mechanism for the uniformization of a-Fe nanocrystals,which is separately induced by the decomposition of the Au–p clusters and the pre-existing a-Fe nanocrystals during *** work underscores the crucial significance of micro-alloying via metastable clusters primarily influenced by metal-phosphide interactions in the process of refining a-Fe ***,i introduces a new principle for optimizing the comprehensive properties of Fe-based amorphous/nanocrystalline alloys.

关键词： Fe-based nanocrystalline alloys In-situ nano-crystallization Micro-alloying Soft magnetic property

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Interdecadal changes in the western Siberian summer mean and extreme rainfall during 1982-2021

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Atmospheric and Oceanic Science Letters 2024年第3期17卷 37-41页

作者： Yali Zhu Fangwu Song Dong guo Nansen-Zhu International Research Centre Institute of Atmospheric PhysicsChinese Academy of SciencesBeijingChina Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science and TechnologyNanjingChina Carbon Neutrality Research Center Institute of Atmospheric PhysicsChinese Academy of SciencesBeijingChina College of Earth and planetary Sciences University of Chinese Academy of SciencesBeijingChina

本文研究发现,西西伯利亚夏季降水在1995年后显著增加,2012年后又有所减少,极端降水日数和强度呈现一致的变化特征.伴随这两次降水的年代际增加/减少,西西伯利亚上空出现异常气旋/反气旋和水汽幅合/幅散.极端降水发生时的区域环流特征... 详细信息

本文研究发现,西西伯利亚夏季降水在1995年后显著增加,2012年后又有所减少,极端降水日数和强度呈现一致的变化特征.伴随这两次降水的年代际增加/减少,西西伯利亚上空出现异常气旋/反气旋和水汽幅合/幅散.极端降水发生时的区域环流特征在三个时段基本一致:西西伯利亚低空出现气旋性异常,高空为西北-东南向的异常气旋-反气旋偶极子型.1995-2011年期间,极端降水日数更多,强度更强,上述异常环流型也更强.

关键词：西伯利亚夏季降水年代际变化乌拉尔高压北大西洋波流相互作用

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Construction of novel p-Si/TiO_(2)/HfO_(2)/MoS_(2)/pt heterophotocathode for enhanced photoelectrochemical water splitting

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Nano Research 2024年第5期17卷 4428-4436页

作者： Jiaru Li Jiayu Bai Songjie Hu Wenyu Yuan Yuyu Bu Xiaohui guo Key Lab of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education Shaanxi Key Laboratory for Carbon Neutral TechnologyThe College of Chemistry and Materials ScienceNorthwest UniversityXi'an 710069China Key Lab of Wide Band-Gap Semiconductor Materials and Devices School of MicroelectronicsXidian UniversityXi’an 710071China Key Lab of Macromolecular Science of Shaanxi province Key Laboratory of Applied Surface and Colloid ChemistryMinistry of EducationSchool of Chemistry&Chemical EngineeringShaanxi Normal UniversityXi'an 710062China

photoelectrochemical devices have been developed to enable the conversion of solar ***,their commercial potential is restricted by the limited stability of the materials *** enhance the stability of photocathode and its solar water splitting performance,a p-Si/TiO_(2)/HfO_(2)/MoS_(2)/pt composite photocathode is developed in this *** novel TiO_(2)/HfO_(2)/MoS_(2) serial nanostructure provides excellent stability of the photocathode,and optimizes the interface energy barrier to further facilitate the transfer process of photogenerated carriers within the *** best p-Si/TiO_(2)/HfO_(2)/MoS_(2)/pt photocathode demonstrates an initial potential of 0.5 V(***)and a photocurrent density of-29 mA/cm^(2) at 0 V(***).Through intensity modulated photocurrent spectroscopy and photoluminescence test,it is known that the enhanced water splitting performance is attributed to the optimized carrier transfer *** findings provide a feasible strategy for the stability and photon quantum efficiency enhancement of silicon-based photocathode devices.

关键词： photoelectrochemical water splitting stability surface/interface engineering HfO_(2)layer

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View of thermodynamic phase transition of the charged Gauss-Bonnet AdS black hole via the shadow

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Chinese physics B 2024年第4期33卷 355-362页

作者：何柯腱郭森罗智李国平 College of physics Chongqing UniversityChongqing 401331China Guangxi Key Laboratory for Relativistic Astrophysics School of Physical Science and TechnologyGuangxi UniversityNanning 530004China School of physics and Astronomy China West Normal UniversityNanchong 637000China

We examine thermodynamic phase transition(pT)of the charged Gauss-Bonnet Ad S black hole(BH)by utilizing the shadow *** this system,we rescale the corresponding Gauss-Bonnet coefficientαby a factor of 1/(D-4),and ensure thatαis positive to avoid any singularity *** equation derived for the shadow radius indicates that it increases as the event horizon radius increases,making it an independent variable for determining BH *** investigating the pT curve in relation to shadows,we can observe that the shadow radius can be used as an alternative to the event horizon radius in explaining the phenomenon of BH ***,the results indicate that an increase in the parameterαcorresponds to a decrease in the temperature of the *** utilizing the relationship between the temperature and the shadow radius,it is possible to obtain the thermal profile of the Gauss-Bonnet AdS *** is evident that there is an N-type variation in temperature for pressures pp_(c).Additionally,as the parameterαincreases,the region covered by shadow expands while the temperature *** utilization of BH shadows as a probe holds immense significance in gaining a deeper understanding of BH thermodynamic behavior.

关键词： Gauss-Bonnet AdS black hole thermodynamic shadow

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The dynamics of traveling wavefronts for a model describing host tissue degradation by bacteria

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International Journal of Biomathematics 2024年第3期17卷 265-287页

作者： Xing-Xing Yang guo-Bao Zhang Ge Tian College of Mathematics and Statistics Northwest Normal University Lanzhou Gansu 730070P.R.China

In this paper,we mainly investigate the dynamics of traveling wavefronts for a model describing host tissue degradation by *** first establish the existence of spreading speed,and show that the spreading speed coincides with the minimal wave speed of traveling ***,a lower bound estimate of the spreading speed is ***,we prove that the traveling wavefronts with large speeds are globally exponentially stable,when the initial perturbation around the traveling wavefronts decays exponentially asχ→-∞,but the initial perturbation can be arbitrarily large in other *** adopted methods are the weighted energy and the squeezing technique.

关键词： Host tissue degradation bacterial infection traveling wavefronts minimal wave speed stability

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High-performance self-powered GaN/pEDOT:pSS hybrid heterojunction UV photodetector for optical communication

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Science China(Technological Sciences) 2024年第2期67卷 608-615页

作者： LI Shan LIU Zeng ZHANG MaoLin YANG LiLi guo YuFeng TANG WeiHua College of Integrated Circuit Science and Engineering&National and Local Joint Engineering Laboratory for RF Integration and Micro-packing Technologies Nanjing University of Posts and TelecommunicationsNanjing 210023China

Self-powered ultraviolet photodetectors(UVpDs)provide great possibility for the next-generation energy conservation optical communication technology;while the high photodetection performance at zero bias is still a tremendous ***,ntype GaN film with Si-doping concentration of~1018cm^(-3)and p-type organic pEDOT:pSS were adopted to construct a planar hybrid heterojunction via the simple spin-coating *** from typical type-Ⅱenergy band alignment and giant photovoltaic effect at GaN/pEDOT:pSS inorganic-organic interface,the fabricated UVpD achieved excellent self-powered photoelectrical properties in dual-band with large R of 0.96 A/W(2.8 A/W),superior D*of 5.7×1012Jones(1.7×10^(13)Jones),prominent EQE of 325%(1371%),high on/off ratio of 9.65×10^(3)(6.15×10^(3))and fast rise/decay time of 60.7/124.5 ms(30.9/26.7 ms)for UVA(UVC)band,as well as outstanding UV/visible rejection ratio and great detection *** as an optical signal receiver,this designed self-powered UVpD decoded a message of“NJUpT”from a simple optical communication *** results open a new avenue for GaN/pEDOT:pSS heterojunction in UV communications and related applications.

关键词： GaN UV photodetector self-powered heterojunction optical communication

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How the microenvironment dominated by the distance effect to regulate the FeN_(4)site ORR activity and selectivity?

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Nano Research 2024年第6期17卷 5735-5741页

作者： peng Li Qingfeng guo Jianrui Zhang Ruilin Chen Shujiang Ding Yaqiong Su School of Chemistry Engineering Research Center of Energy Storage Materials and Devices of Ministry of EducationNational Innovation Platform(Center)for Industry-Education Integration of Energy Storage TechnologyXi’an Jiaotong UniversityXi’an 710049China Huanghe Science and Technology College Zhengzhou 450063China General Research Institute of Engineering of Gotion High-Tech Hefei 230041China

The distance effect of the doped heteroatoms away from the catalytic centers has rarely been *** this work,we conducted density functional theory calculations to thoroughly investigate the influence of heteroatom(N,p,B,and S atoms)doping distance on the oxygen reduction reaction(ORR)activity of graphene-based FeN_(4)*** uncovered a Sabatier-like relationship between heteroatom doping distance and ORR activity of FeN_(4)*** nearest doping does not significantly improve and even block the ORR activity of FeN_(4)*** ORR activity is achieved when the heteroatoms are 4-5Å(N,p,and S atoms)or 6-7Å(B atoms)away from the Fe *** of electronic structure indicates that distance effect can modulate the local chemical environment of Fe atoms,thereby account for the changes in ORR activity along with the doping distance and doping *** study provides insights into the influence of heteroatom doping on the chemical environment of reaction active centers,and provides the theoretical guidance for controlling the doping distance of heteroatoms to achieve optimal catalytic activity and selectivity.

关键词： distance effect microenvironment heteroatom doping FeN_(4) Sabatier-like relationship structure-activity relationship

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Highly selective and eco-friendly dihydroisoquinoline synthesis via Cu/Co synergistic catalysis in Cu Nps@MOFs catalyst under mild conditions

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Science China Chemistry 2024年第5期67卷 1561-1568页

作者： peng-Fei guo Ze-Long Liang Yue-E Jiao Hang Xu Bin Zhao Key Laboratory of Advanced Energy Material Chemistry Renewable Energy Conversion and Storage CenterDepartment of ChemistryNankai UniversityTianjin 300071China

3,4-Dihydroisoquinoline(DHIQ)is an important precursor used in the production of drugs for treating cancer,HIV,Alzheimer's disease,*** studies on DHIQ synthesis show low catalytic selectivity due to the susceptible over-oxidation feedstock of1,2,3,4-tetrahydroisoquinoline(THIQ),which often requires alkali ***,it is desirable yet challenging to explore a highly selective and efficient oxydehydrogenation capacity for DHIQ synthesis under eco-friendly reaction ***,a novel framework 1 was synthesized,exhibiting 1D channels with the size of 4.6 A×9.6 A and high solvent/p H/thermal stability.A stable framework allows it to encapsulate Cu nanoparticles(Nps)to form Cu Nps@1-x(x=1,2,3,and 4)with varying loading amounts of Cu Nps at 2.0 wt%,3.0 wt%,4.0 wt%,and 6.0 wt%,*** Nps@1-3 could selectively catalyze the reaction from THIQ to DHIQ with a high selectivity of 98%and a recorded turnover frequency(TOF)of 22.1 h-1under eco-friendly mild *** corresponding catalytic activity can maintain at least five recyclings and can be further applied to gram-scale ***,the efficient preparation of DHIQ catalyzed by Cu Nps@1-3 could be realized even under air ***,the anticancer molecule precursor synthesis of 6,7-dimethoxy-3,4-dihydroisoquinoline was also selectively catalyzed by Cu Nps@*** investigations revealed that high catalytic performance can be attributed to the stable framework and the synergistic catalytic effect of the loaded Cu Nps and Co metal *** importantly,this work represents the first example of MOF catalysts for selectively thermo-catalytic DHIQ synthesis and demonstrates a simple approach to obtain efficient catalysts for selective oxydehydrogenation in the production of unsaturated compounds.

关键词： metal-organic frameworks Cu Nps@MOFs 3 4-dihydroisoquinoline selective oxydehydrogenation synergistic catalysis

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A Logarithmic Decay of the Energy for the Hyperbolic Equation with Supercritical Damping

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Journal of partial Differential Equations 2024年第2期37卷 150-165页

作者： LI Xiaolei guo Bin School of Mathematics and Statistics Changchun University of Science and TechnologyChangchun 130022China School of Mathematics Jilin UniversityChangchun 130012China

We are concerned with the following quasilinear wave equation involving variable sources and supercritical damping:■Generally speaking,when one tries to use the classical multiplier method to analyze tRhe asymptotic behavior of solutions,an inevitable step is to deal with the integralΩ|ut|^(m−2)utudx.A usual technique is to apply Young’s inequality and Sobolev embedding inequality to use the energy function and its derivative to control this integral for the subcritical or critical ***,for the supercritical case,the failure of the Sobolev embedding inequality makes the classical method be *** do this,our strategy is to prove the rate of the integral RΩ|u|^(m)dx grows polynomially as a positive power of time variable t and apply the modified multiplier method to obtain the energy functional decays *** results improve and extend our previous work[12].Finally,some numerical examples are also given to authenticate our results.

关键词： Energy decay estimate asymptotic behavior p(x)-Laplacian operator supercritical damping

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