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Metastability of π-π stacking between the closed-shell ions of like charges

Chinese Journal of Structural Chemistry 2024年第5期43卷 22-29页

作者： Jiayao li Xinru Peng Shiwei Yin Changwei Wang Yirong Mo Key Laboratory for Macromolecular Science of Shaanxi Province School of Chemistry&Chemical EngineeringShaanxi Normal UniversityXi'an710119China Department of Nanoscience Joint School of Nanoscience&NanoengineeringUniversity of North Carolina at GreensboroGreensboroNC 27401USA

Planar cations or anions can form stacks in crystals or solutions,where the surrounding or environment plays a decisive role as demonstrated in previous ***,it remains unclear whether these counterintuitive interactions possess any inherent stability or are thoroughly repulsive if the constraint of environment is *** this work,we explored the inherent stability ofπ-πstacking between closed-shell ions of like charges with prototypes derived from experimental *** inherent metastability was identified by the characteristic local minima and the transition states preventing their dissociation and verified by ab initio molecular dynamics(AIMD)*** nature of involved interactions was deciphered with the energy decomposition approach based on the block-localized wavefunction method(BLW-ED).like the conventional neutralπ-πstacking interactions,electron correlation is the most attractive energy *** it is overturned by the Coulombic repulsion between net charges for all modes of dimerization,resulting in the overall repulsive inter-cation or anion *** from van der Waals interactions were also observed in the reduced density gradient *** origin of the metastability was elucidated by examining the contributions of individual physical factors to the *** inherent metastability originates from the electron correlation,which dramatically increases due to the enhanced overlap between ions from a transition state to its corresponding minimum.

关键词： π-πstacking interactions Metastability Valence bond theory Energy decomposition analysis Electron correlation

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Effect of Ca Micro-Alloying on the Microstructure and Anti-Corrosion Property of Mg0.5Zn0.2Ge Alloy

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Acta Metallurgica Sinica(English Letters) 2024年第7期37卷 1147-1160页

作者： Bishan Cheng Depeng li Baikang Xing Ruiqing Hou Pingli Jiang Shijie Zhu Shaokang Guan School of Materials Science and Engineering and Henan Key Laboratory of Advanced Magnesium Alloys Zhengzhou UniversityZhengzhou450001China Center of Advanced Analysis and Gene Sequencing Zhengzhou UniversityZhengzhou450001China Key Laboratory of Materials Processing and Mold Technology Ministry of EducationZhengzhou450002China

Magnesium and its alloys have attracting rising attention as one of biodegradable metallic ***,the rapid corrosion and severe localized corrosion still hinder their extensive applications in *** this study,micro-alloying of Ca(≤0.1 wt%)into Mg0.5Zn0.2Ge alloy developed in our previous work was explored to further enhance the corrosion resistance and alleviate the localized corrosion of the *** results reveal that the addition of Ca leads to the transformation of the cathodic Mg_(2)Ge phase in Mg0.5Zn0.2Ca alloy into anodic MgCaGe phase in Ca-containing alloys,thereby changing the galvanic couples in alloys during *** preferential dissolution of MgCaGe phase promotes the participation of Ca and Ge into the formation of corrosion products,resulting in the enrichment of Ca and Ge in the outmost of corrosion product layer,which stabilizes and passivates the corrosion product layer on Mg alloy ***,the enrichment of Zn at the corrosion interface seems to further hinder the corrosion of Mg *** of these factors confer a slower and more uniform corrosion on Mg0.5Zn0.2GexCa(x<0.1 wt%)alloy,which provides favorable candidates for the further processing to gain suitable biodegradable Mg alloys.

关键词： Magnesium alloy Micro-alloying Calcium Corrosion resistance

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Structural and Luminescent Properties of Mg_(0.25-x)Al_(2.57)O_(3.79)N_(0.21):xMn^(2+)Green-Emitting Transparent Ceramic Phosphor

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Journal of Wuhan University of Technology(Materials Science) 2024年第3期39卷 533-540页

作者：郝留成 MIAO Xiaojun li Kai ZHONG Jianying 涂兵田 YANG Zhangfu 王皓 Pinggao Group Co. LtdPingdingshan 467001China State Key Lab of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China Hubei Longzhong Laboratory Xiangyang 430070China School of Materials Science and Engineering Anhui University of Science and TechnologyHuainan 232001China

A series of spinel-type Mg_(0.25-x)Al_(2.57)O_(3.79)N_(0.21):xMn^(2+)(MgAlON:xMn^(2+))phosphors were synthesized by the solid-state reaction *** transparent ceramic phosphors were fabricated by pressureless sintering followed by hot-isostatic pressing(HIP).The crystal structure,luminescence and mechanical properties of the samples were systematically *** transparent ceramic phosphors with tetrahedrally coordinated Mn^(2+)show strong green emission centered around 515 nm under blue light *** the Mn^(2+)concentration increases,the crystal lattice expands slightly,resulting in a variation of crystal field and a slight red-shift of green emission *** weak absorption peaks in the transmittance spectra originate from the spin-forbidden ^(4)T_(1)(^(4)G)→^(6)A_(1) transition of Mn^(2+).The decay time was found to decrease from 5.66 to 5.16 ms with the Mn^(2+)*** present study contributes to the systematic understanding of crystal structure and properties of MgAlON:xMn^(2+)green-emitting transparent ceramic phosphor which has a potential application in high-power light-emitting diodes.

关键词： transparent ceramic phosphor green emission MgAlON photoluminescence

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Precise control of page cache for containers

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Frontiers of Computer Science 2024年第2期18卷 17-30页

作者： Kun WANG Song WU Shengbang li Zhuo HUANG Hao FAN Chen YU Hai JIN National Engineering Research Center for Big Data Technology and System Services Computing Technology and System LabCluster and Grid Computing Lab School of Computer Science and TechnologyHuazhong University of Science and TechnologyWuhan 430074China

Container-based virtualization isbecoming increasingly popular in cloud computing due to its efficiency and *** isolation is a fundamental property of *** works have indicated weak resource isolation could cause significant performance degradation for containerized applications and enhanced resource ***,current studies have almost not discussed the isolation problems of page cache which is a key resource for *** leverage memory cgroup to control page cache ***,existing policy introduces two major problems in a container-based ***,containers can utilize more memory than limited by their cgroup,effectively breaking memory ***,the Os kernel has to evict page cache to make space for newly-arrived memory requests,slowing down containerized *** paper performs an empirical study of these problems and demonstrates the performance impacts on containerized *** we propose pCache(precise control of page cache)to address the problems by dividing page cache into private and shared and controlling both kinds of page cache separately and *** do so,pCache leverages two new technologies:fair account(f-account)and evict on demand(EoD).F-account splits the shared page cache charging based on per-container share to prevent containers from using memory for free,enhancing memory *** EoD reduces unnecessary page cache evictions to avoid the performance *** evaluation results demonstrate that our system can effectively enhance memory isolation for containers and achieve substantial performance improvement over the original page cache management policy.

关键词： page cache memory cgroup container isolation cloud computing

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Recyclable High-performance Carbon Fiber Reinforced Epoxy Composites Based on Dithioacetal Covalent Adaptive Network

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Chinese Journal of Polymer Science 2024年第10期42卷 1514-1524,I0011页

作者： Gui-lian Shi Ting-Cheng li Dao-Hong Zhang Jun-Heng Zhang Key Laboratory of Catalysis and Energy Materials Chemistry of Ministry of Education&Hubei Key Laboratory of Catalysis and Materials Science Hubei R&D Center of Hyperbranched Polymers Synthesis and ApplicationsSouth-Central Minzu UniversityWuhan430074China State Key Laboratory of New Textile Materials and Advanced Processing Technologies Wuhan Textile UniversityWuhan430200China Ministry-of-Education Key Laboratory for the Green Preparation and Application of Functional Materials Hubei UniversityWuhan430062Chin

Recycling of carbon fiber reinforced composites is important for sustainable development and the circular *** the use of dynamic chemistry,developing high-strength recyclable CFRPs remains a major challenge due to the mutual exclusivity between the dynamic and mechanical properties of ***,we developed a high-strength recyclable epoxy resin(HREP)based on dynamic dithioacetal covalent adaptive network using diglycidyl ether bisphenol A(DGEBA),pentaerythritol tetra(3-mercapto-propionate)(PETMP),and vanillin epoxy resin(VEPR).At high temperatures,the exchange reaction of thermally activated dithioacetals accelerated the rearrangement of the network,giving it significant reprocessing ***,HREP exhibited excellent solvent resistance due to the increased cross-linking *** this high-strength recyclable epoxy resin as the matrix and carbon fiber modified with hyperbranched ionic liquids(HBP-AMIM+PF6-)as the reinforcing agent,high performance CFRPs were successfully *** tensile strength,interfacial shear strength(IFSS)and interlaminar shear strength(ILSS)of the optimized formulation(HREP20/CF-HBPPF6)were 1016.1,70.8 and 76.0 MPa,*** addition,the CFRPs demonstrated excellent solvent and acid/*** CFRPs could completely degrade within 24 h in DMSO at 140℃,and the recycled CF still maintained the same tensile strength and ILSS as the original after multiple degradation cycles.

关键词： Epoxy resin Hyperbranched ionic liquid Recycling Carbon fiber Composites

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Recent process in developing advanced heterogeneous diatomic-site metal catalysts for electrochemical CO_(2)reduction

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Chinese Chemical Letters 2024年第7期35卷 4-13页

作者： Xueyang Zhao Bangwei Deng Hongtao Xie Yizhao li Qingqing Ye Fan Dong Yangtze Delta Region Institute(Huzhou) University of Electronic Science and Technology of ChinaHuzhou 313001China Institute of Fundamental and Frontier Sciences University of Electronic Science and Technology of ChinaChengdu 611731China Suzhou Industrial Technology Research Institute of Zhejiang University Zhejiang UniversitySuzhou 215159China

Diatomic-site catalysts(DASCs)have emerged as a kind of promising heterogeneous candidate catalysts for electrochemical CO_(2)reduction(ECR),which is considered to retain the advantage of single-atom catalysts(SACs)but also introduce opportunities to exceed the limit of single-atom *** the past few years,tremendous progress has been achieved in this ***,the recent progress in ECR on DASCs has been *** will start with the classification of *** the challenges in the precise fabrication and characterization of DASCs have been *** introducing the advanced ECR performance on DASCs,superior to that on SACs,the synergistic effects of the dual metal atoms are highlighted,as this origin of the advanced ECR performance on DASCs is comprehensively ***,the major challenges and perspectives of DASCs have been proposed to shed light on the development of DASCs for ECR application.

关键词： Diatomic-site metal catalyst Electrochemical CO_(2)reduction Classification CO_(2)activation Synergistic effects

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All-dielectric terahertz metasurface governed by bound states in the continuum with high-Q factor

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The Journal of China Universities of Posts and Telecommunications 2024年第2期31卷 44-54页

作者： li Kun Zhao Xu Wang Meng Jia Xingning Zhao Ruiqi Lu Guizhen School of Integrated Circuit Science and Engineering Tianjin University of TechnologyTianjin 300384China School of Electronic and Electrical Engineering Ningxia UniversityYinchuan 750021China QILU Aerospace Information Research Institute Chinese Academy of Sciences(CAS)Jinan 250101China State Key Laboratory of Media Convergence and Communication Communication University of ChinaBeijing 100024China

The method of terahertz(THz)resonance with a high-quality(high-Q)factor offers a vital physical mechanism for metasurface sensors and other high-Q factor ***,it is challenging to excite the resonance with a high-Q factor in metasurfaces with proper sensitivity as well as figure of merit(FOM)***,an all-dielectric metasurface composed of two asymmetrical rectangular blocks is *** and silicon are the materials applied for the substrate and cuboids *** distinct resonance governed by bound states in the continuum(BIC)is excited by forming an asymmetric cluster by a novel hybrid method of cutting and moving the *** investigation focuses on analyzing the transmission spectra of the metasurface under different variations in structural parameters and the loss of silicon refractive *** the proposed defective metasurface serves as a transmittance sensor,it shows a Q factor of 1.08×10^(4)and achieves an FOM up to 4.8×10^(6),which is obtained under the asymmetric parameter equalling 1μ***,the proposed defective metasurface is sensitive to small changes in refractive *** the thickness of the analyte is 180μm,the sensitivity reaches a maximum value of 578 GHz/***,the proposed defective metasurface exhibits an extensive number of possible applications in the filters,biomedical diagnosis,security screening,and so on.

关键词： terahertz(THz)metasurface high-quality(high-Q)factor bound states in the continuum figure of merit(FOM)

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Effect of biochar application on rice,wheat,and corn seedlings in hydroponic culture

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Journal of Environmental Sciences 2024年第1期135卷 379-390页

作者： Yingjie Yin Jikai li Sihang Zhu Qing Chen Chong Chen Yukui Rui Jianying Shang College of Land Science and Technology China Agricultural UniversityKey Laboratory of Plant-Soil InteractionsMinistry of Educationand Key Laboratory of Arable Land Conservation in North ChinaMinistry of Agriculture and Rural AffairsBeijing 100193China Agricultural Management Institute Ministry of Agriculture and Rural AffairsBeijing 102208China College of Resources and Environmental Sciences China Agricultural UniversityBeijing Key Laboratory of Farmland Soil Pollution Prevention and RemediationBeijing 100193China

In recent years,biochar has attracted considerable attention for soil quality improvement and carbon sequestration due to its unique physicochemical ***,the mechanism by which biochar application negatively affects the growth of crop seedlings has not been fully *** this study,a hydroponic experiment was conducted to evaluate the response of rice,wheat,and corn seedlings to biochar application(CK,0 g/L;BC1,0.5 g/L;and BC2,1.0 g/L).Compared with the CK treatment,the BC1 and BC2 treatments decreased the fresh shoot and root weights of rice and corn seedlings(Plings(P>0.05).For the contents of nutrient elements in seedlings,both BC1 and BC2 treatments hindered the roots from absorbing Fe and Cu and increased the uptake of Ca and *** with the CK treatment,the translocation factor(TF)values of Ca,Mn,and Zn were significantly decreased especially in rice seedlings(35.3%-36.8%,68.7%-76.5%,and 29.8%-22.0%,respectively)under the BC1 and BC2 treatments,while only Mn was significantly decreased in wheat and corn seedlings(Plication can reduce nutrient absorption and translocation,and hinder rice,wheat,and corn seedlings,particularly rice seedling,in hydroponic system.

关键词： Biochar Toxicity Seedling growth Hydroponic cultivation

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Optical edge-to-screw singularity state conversions

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Photonics Research 2024年第8期12卷 1689-1695页

作者： HAOliN liN JUNHUI JIA GUOHUA liU YANWEN HU ZHEN li ZHENQIANG CHEN SHENHE FU Department of Optoelectronic Engineering Jinan UniversityGuangzhou 510632China Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications Guangzhou 510632China Guangdong Provincial Engineering Research Center of Crystal and Laser Technology Guangzhou 510632China

Optical singularity states,which significantly affect propagation properties of light in free space or optical medium,can be geometrically classified into screw and edge *** different types of singularity states do not exhibit direct connection,being decoupled from each other in the absence of external *** we demonstrate a novel optical process in which a higher-order edge singularity state initially nested in the propagating Gaussian light field gradually involves into a screw singularity with a new-born topological charge determined by order of the edge *** considered edge state comprises an equal superposition of oppositely charged vortex and antivortex *** theoretically and experimentally realize this edge-to-screw conversion process by introducing intrinsic vortex–antivortex *** also present a geometrical representation for mapping this dynamical process,based on the higher-order orbital Poincaré*** this framework,the edge-to-screw conversion is explained by a mapping of state evolution from the equator to the north or south pole of the Poincaré*** demonstration provides a novel approach for manipulating singularity state by the intrinsic vortex–antivortex *** presented phenomenon can be also generalized to other wave systems such as matter wave,water wave,and acoustic wave.

关键词： interaction Poincaré wave

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Dual sliding mode coordinated control of manipulator grasping system with visual assistance

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Control Theory and Technology 2024年第1期22卷 106-121页

作者： Pengxin Zhang Haisheng Yu Xiangxiang Meng Zhe li Qing Yang Xunkai Gao College of Automation Qingdao UniversityQingdao266071ShandongChina Shandong Province Key Laboratory of Industrial Control Technology Qingdao266071ShandongChina

The operation efficiency of the manipulator is placed in the primary position in automatic production. This paper proposes a coordinated control strategy for joint servo and visual servo to enable timely transfer and accurate gripping in the working area. Aiming at the issues of chattering and slow convergence of traditional sliding mode controller, a fast variable power reaching rate on the basis of the non-singular fast terminal sliding mode controller is proposed, which can effectively reduce the convergence time and chattering. For the purpose of addressing the problem that the traditional visual servo control method is sensitive to the environment, a visual servo controller based on integral sliding mode is proposed, to ensure the favorable positioning accuracy of the manipulator. Based on the two proposed controllers mentioned above, a coordinated control strategy is used to implement the control of the manipulator. Finally, the upper computer software is developed using the C# programming language to monitor the workstation. The feasibility of the above-mentioned method is verified through multiple simulations and experiments.

关键词： Automatic production Joint servo Visual servo Coordinated control Non-singular fast terminal sliding mode Integral sliding mode

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