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Strain tunable excitonic optical properties in monolayer Ga_(2)O_(3)

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Chinese Physics B 2024年第10期33卷 366-370页

作者： Hao-lei Cui zhen Quan shu-Dong wang School of Physical Science and Technology Inner Mongolia UniversityHohhot 010021China

Two-dimensional(2D)Ga_(2)O_(3)has been confirmed to be a stable structure with five atomic layer thickness *** this work,we study the quasi-particle electronic band structures and then access the excitonic optical properties through solving the Bethe-Salpeter equation(BSE).The results reveal that the exciton dominates the optical absorption in the visible light region with the binding energy as large as~1.0 eV,which is highly stable at room ***,both the dominant absorption P_(1)and P_(2)peaks are optically bright without dark exciton between them,and thus is favorable for luminescence *** calculated radiative lifetime of the lowest-energy exciton is 2.0×10^(-11)s at 0 ***,the radiative lifetime under+4%tensile strain is one order of magnitude shorter than that of the strainfree case,while it is less insensitive under the compressive *** findings set the stage for future theoretical and experimental investigation on monolayer Ga_(2)O_(3).

关键词： excitons radiative lifetime Ga_(2)O_(3)

The Complete Classification of Graphs whose Second Largest Eigenvalue of the Eccentricity Matrix is Less Than 1

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Acta Mathematica Sinica,English Series 2024年第7期40卷 1741-1766页

作者： Jian Feng wang Xing yu lei shu Chao LI Zoran STANIC School of Mathematics and Statistics Shandong University of TechnologyZibo255049P.R.China Faculty of Mathematics and Statistics Central China Normal UniversityWuhan430079P.R.China Faculty of Mathematics University of BelgradeStudentski trg 1611000BelgradeSerbia

The eccentricity matrix of a graph is obtained from the distance matrix by keeping the entries that are largest in their row or column,and replacing the remaining entries by *** matrix can be interpreted as an opposite to the adjacency matrix,which is on the contrary obtained from the distance matrix by keeping only the entries equal to *** the paper,we determine graphs having the second largest eigenvalue of eccentricity matrix less than 1.

关键词： Eccentricity matrix eigenvalue diameter principal submatrix forbidden subgraph

Polymer-to-Monomers Chemically Recyclable Poly(imide-imine)Plastics with Extreme-Condition Resistance and Flame Retardancy

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Chinese Journal of Polymer Science 2024年第10期42卷 1525-1535,I0012页

作者： zhen-yu wang Xiao-Kong Liu State Key Laboratory of Supramolecular Structure and Materials College of ChemistryJilin UniversityChangchun130012China

Polyimides are a family of high-tech plastics that have irreplaceable applications in the fields of aerospace,defense,and opto-electronics,but polyimides are difficult to be reprocessed and recycled at the end of their service life,resulting in a significant waste of ***,it is of great significance to develop recyclable polyimides with comparable properties to the commercial ***,we report a novel polymer-to-monomers chemically recyclable poly(imide-imine)(PtM-CR-PII)plastic,synthesized by cross-linking the amine-terminated aromatic bisimide monomer and the hexa-vanillin terminated cyclophosphazene monomer via dynamic imine *** PtM-CR-PII plastic exhibits comparable mechanical and thermal properties as well as chemical stability to the commercial *** PtM-CR-PII plastic possesses a high Young’s modulus of≈3.2 GPa and a tensile strength as high as≈108 MPa,which also exhibits high thermal stability with a glass transition temperature of≈220℃.Moreover,the PtM-CR-PII plastic exhibits outstanding waterproofness,acid/alkali-resistance,and solvent-resistance,its appearance and mechanical properties can be well maintained after long-term soaking in water,highly concentrated acid and base,and various organic ***,the cyclophosphazene moieties endow the PtM-CR-PII plastic with excellent flame *** PtM-CR-PII plastic exhibits the highest UL-94 flame-retarding rating of V-0 and a limiting oxygen index(LOI)value of 45.5%.Importantly,the PtM-CR-PII plastic can be depolymerized in an organic solvents-acid mixture medium at room temperature,allowing easy separation and recovery of both monomers in high *** recovered pure monomers can be used to regenerate new PtM-CR-PII plastics,enabling sustainable polymer-monomers-polymer circulation.

关键词： Chemical recyclability Polyimides Polyimines Dynamic imine bonds Mechanical properties Chemical stability

Collaborative Charging Scheduling in Wireless Charging Sensor Networks

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Computers, Materials & Continua 2024年第4期79卷 1613-1630页

作者： Qiuyang wang zhen Xu lei Yang School of Electrical and Electronic Engineering Wuhan Polytechnic UniversityWuhan430048China

Wireless sensor networks (WSNs) have the trouble of limited battery power, and wireless charging provides apromising solution to this problem, which is not easily affected by the external environment. In this paper, we studythe recharging of sensors in wireless rechargeable sensor networks (WRSNs) by scheduling two mobile chargers(MCs) to collaboratively charge sensors. We first formulate a novel sensor charging scheduling problem with theobjective of maximizing the number of surviving sensors, and further propose a collaborative charging schedulingalgorithm(CCSA) for WRSNs. In the scheme, the sensors are divided into important sensors and ordinary *** can adaptively collaboratively charge the sensors based on the energy limit ofMCs and the energy demandof sensors. Finally, we conducted comparative simulations. The simulation results show that the proposed algorithmcan effectively reduce the death rate of the sensor. The proposed algorithm provides a solution to the uncertaintyof node charging tasks and the collaborative challenges posed by multiple MCs in practical scenarios.

关键词： Wireless rechargeable sensor network mobile charger collaborative charging adaptive charging

Cu-substituted nickel hexacyanoferrate with tunable reaction potentials for superior ammonium ion storage

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Journal of Materials Science & Technology 2024年第2期169卷 19-27页

作者： leiyu Fan Guangchang shu Yiwen Liu Haoxiang yu lei Yan Liyuan Zhang Jie shu School of Materials Science and Chemical Engineering Ningbo UniversityNingbo 315211China

In this work,a variety of Cu_(x)Ni_(2-x)Fe(CN)_(6)(x=0,0.4,0.8,1.2,1.6,2)cathodes for ammonium ion batteries are prepared and their electrochemical performances are *** the introduction of copper in nickel hexacyanoferrate,the electrochemical performance varies without changing the structure of nickel *** increase of Cu content in nickel hexacyanoferrate leads to the enhancement of reaction potential and *** results suggest that the substitution of Cu for Ni has a positive effect on improving the cycling stability and rate capacity of nickel hexacyanoferrate when x in Cu_(x)Ni_(2-x)Fe(CN)_(6)is less than ***,Cu_(0.4)Ni_(1.6)Fe(CN)_(6)exhibits the best cycling per-formance(capacity retention of 97.54%at 0.3 C)and the highest rate capacity(41.4 mAh g^(-1)at 10 C)in Cu_(x)Ni_(2-x)Fe(CN)_(6).Additionally,the X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS)tests also reveal that the structural evolution of Cu_(0.4)Ni_(1.6)Fe(CN)_(6)is highly reversible upon NH_(4)^(+)***,this work proposes a candidate material for ammoniumion batteries and offers a novel avenue for adjusting the operating potential of the material.

关键词： Nickel hexacyanoferrate Copper hexacyanoferrate NH_(4)^(+)storage Ammonium ion batteries Aqueous batteries

Experimental study of the effects of a multistage pore-throat structure on the seepage characteristics of sandstones in the Beibuwan Basin:Insights into the flooding mode

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Petroleum Science 2024年第2期21卷 1044-1061页

作者： lei wang Xiao lei Qiao-Liang Zhang Guang-Qing Yao Bo Sui Xiao-Jun Chen Ming-Wei wang zhen-yu Zhou Pan-Rong wang Xiao-Dong Peng Zhanjiang Branch China National Offshore Oil Corporation(CNOOC)LimitedZhanjiang524057GuangdongChina Faculty of Earth Resources China University of Geosciences(Wuhan)Wuhan430074HubeiChina School of Resources and Safety Engineering Chongqing UniversityChongqing400044China School of Engineering University of ManchesterManchester M139WJUK Hainan Branch China National Offshore Oil Corporation(CNOOC)LimitedHaikou570311HainanChina

To investigate the relationship between grain sizes, seepage capacity, and oil-displacement efficiency in the Liushagang Formation of the Beibuwan Basin, this study identifies the multistage pore-throat structure as a crucial factor through a comparison of oil displacement in microscopic pore-throat experiments. The two-phase flow evaluation method based on the Li-Horne model is utilized to effectively characterize and quantify the seepage characteristics of different reservoirs, closely relating them to the distribution of microscopic pores and throats. It is observed that conglomerate sandstones at different stages exhibit significant heterogeneity and noticeable differences in seepage capacity, highlighting the crucial role played by certain large pore throats in determining seepage capacity and oil displacement efficiency. Furthermore, it was found that the displacement effects of conglomeratic sandstones with strong heterogeneity were inferior to those of conventional homogeneous sandstone, as evidenced by multiple displacement experiments conducted on core samples with varying granularities and flooding systems. Subsequently, core-based experiments on associated gas flooding after water flooding were conducted to address the challenge of achieving satisfactory results in a single displacement mode for reservoirs with significant heterogeneity. The results indicate that the oil recovery rates for associated gas flooding after water flooding increased by 7.3%-16.4% compared with water flooding alone at a gas-oil ratio of approximately 7000 m^(3)/m^(3). Therefore, considering the advantages of gas flooding in terms of seepage capacity, oil exchange ratio, and the potential for two-phase production, gas flooding is recommended as an energy supplement mode for homogeneous reservoirs in the presence of sufficient gas source and appropriate tectonic angle. On the other hand, associated gas flooding after water flooding is suggested to achieve a more favorable develop

关键词： Beibuwan Basin Multistage pore-throat structure Multistage seepage characteristics Microscopic visualization Heterogeneity Gas/water flooding Flooding mode

Advancements and challenges in bionic joint lubrication biomaterials for sports medicine

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Biosurface and Biotribology 2024年第3期10卷 89-105页

作者： lei Xiang zhen wang Wenguo Cui Department of Orthopaedics Shanghai Key Laboratory for Prevention and Treatment of Bone and Joint DiseasesShanghai Institute of Traumatology and OrthopaedicsRuijin HospitalShanghai Jiao Tong University School of MedicineShanghaiChina

Bionic lubricant materials are a class of materials inspired by natural organisms and offer excellent lubrication properties and *** the field of sports medicine,their application opens up new possibilities for the prevention and treatment of sports-related *** authors will introduce the existing theoretical models of friction in the locomotor system,the characteristics and advantages of biomimetic lubrication materials and discuss in depth their applications in the field of sports *** development of bionic lubrication materials opens up unprecedented opportunities for sports medicine to provide more effective and long-lasting treatment options for patients.

关键词： biointerface bio-lubricant biomaterials biomedical application medicine

Inhibition of Defect-Induced Ice Nucleation, Propagation, and Adhesion by Bioinspired Self-Healing Anti-Icing Coatings

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Research 2024年第1期2023卷 237-246页

作者： shu Tian Ruiqi Li Xinmeng Liu Jiancheng wang Junyu yu Sijia Xu yunqing Tian Jing Yang lei Zhang Department of Biochemical Engineering Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering(MOE)School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300350China Binzhou Institute of Technology Weiqiao-UCAS Science and Technology ParkBinzhou CityShandong Province 256606China

Anti-icing coatings on outdoor infrastructures inevitably suffer from mechanical injuries in numerous icing scenarios such as hailstorms,sandstorms,impacts of foreign objects,and icing–deicing ***,the mechanisms of surface-defect-induced icing are *** the defects,water molecules exhibit stronger adsorption and the heat transfer rate increases,accelerating the condensation of water vapor as well as ice nucleation and ***,the ice–defect interlocking structure increases the ice adhesion ***,a self-healing(at−20℃)antifreeze-protein(AFP)-inspired anti-icing coating is *** coating is based on a design that mimics the ice-binding and non-ice-binding sites in *** enables the coating to markedly inhibit ice nucleation(nucleation temperature<−29.4℃),prevent ice propagation(propagation rate<0.00048 cm^(2)/s),and reduce ice adhesion on the surface(adhesion strength<38.9 kPa).More importantly,the coating can also autonomously self-heal at−20℃,as a result of multiple dynamic bonds in its structure,to inhibit defect-induced icing *** healed coating sustains high anti-icing and deicing performance even under various extreme *** work reveals the in-depth mechanism of defect-induced ice formation as well as adhesion,and proposes a self-healing anti-icing coating for outdoor infrastructures.

关键词： coating defect clarified

Decentralized Primary Frequency Regulation for Hybrid Multi-terminal Direct Current Power Systems Considering Multi-source Enhancement

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Journal of Modern Power Systems and Clean Energy 2024年第3期12卷 958-970页

作者： Jialiang Wu zhen wang Ruixu Liu yu Shan Chenxuan wang the College of Electrical Engineering Zhejiang UniversityHangzhou 310027China the Economic Research Institute of State Grid Zhejiang Electric Power Co. Ltd.Hangzhou 310016China

Hybrid multi-terminal direct current(MTDC)transmission technology has been a research focus,and primary frequency regulation(FR)improvement in the receiving-end system is one of the problems to be *** paper presents a decentralized primary FR scheme for hybrid MTDC power systems considering multi-source enhancement to help suppress frequency disturbance in the receiving-end *** the converters only need local frequency or DC voltage signal input to respond to system disturbance without communication or a control center,i.e.,a decentralized control *** proposed scheme can activate appropriate power sources to assist in FR in various system disturbance severities with fine-designed thresholds,ensuring sufficient utilization of each power *** better balance FR performance and FR resource participation,an evaluation index is proposed and the parameter optimization problem is further ***,the validity of the proposed scheme is verified by simulations in MATLAB/Simulink.

关键词： Decentralized control scheme primary frequency regulation(FR) rate of change of frequency(ROCOF) system frequency disturbance