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Enhancing MXene-based supercapacitors:Role of synthesis and 3D architectures

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Journal of Energy Chemistry 2024年第4期91卷 1-26页

作者： Wen Siong Poh Wen Jie yiang Wee-Jun ong Pau Loke Show Chuan yi Foo School of Energy and Chemical Engineering Xiamen University MalaysiaSelangor Darul EhsanMalaysia&College of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005FujianChina Kelip-kelip!Center of Excellence for Light Enabling Technologies Xiamen University MalaysiaSelangor Darul Ehsan 43900Malaysia Center of Excellence for NaNo Energy&Catalysis Technology(CONNECT) Xiamen University MalaysiaSelangor Darul Ehsan 43900Malaysia Department of Chemical Engineering Khalifa UniversityShakhbout Bin Sultan St-Zone 1Abu DhabiUnited Arab Emirates Zhejiang Provincial Key Laboratory for Subtropical Water Environment and Marine Biological Resources Protection Wenzhou UniversityWenzhou 325035ZhejiangChina Department of Chemical and Environmental Engineering Faculty of Science and EngineeringUniversity of Nottingham MalaysiaJalan Broga43500 SemenyihSelangor Darul EhsanMalaysia Department of Sustainable Engineering Saveetha School of EngineeringSIMATSChennai 602105India

MXene has been the limelight for studies on electrode active materials,aiming at developing supercapacitors with boosted energy density to meet the emerging influx of wearable and portable electronic *** its various desirable properties including intrinsic flexibility,high specific surface area,excellent metallic conductivity and unique abundance of surface functionalities,its full potential for electrochemical performance is hindered by the notorious restacking phenomenon of MXene *** to its two-dimensional(2D)nature and surface functional groups,inevitable Van der Waals interactions drive the agglomeration of nanosheets,ultimately reducing the exposure of electrochemically active sites to the electrolyte,as well as severely lengthening electrolyte ion transport *** a result,energy and power density deteriorate,limiting the application versatility of MXene-based *** 3D architectures using 2D nanosheets presents as a straightforward yet ingenious approach to mitigate the fatal flaws of ***,the sheer number of distinct methodologies reported,thus far,calls for a systematic review that unravels the rationale behind such 3D MXene structural ***,this review aims to serve this purpose while also scrutinizing the structure–property relationship to correlate such structural modifications to their ensuing electrochemical performance ***,the physicochemical properties of MXene play fundamental roles in determining the effective charge storage capabilities of 3D MXene-based *** largely depends on different MXene synthesis techniques and synthesis condition variations,hence,elucidated in this review as ***,the challenges and perspectives for achieving viable commercialization of MXene-based supercapacitor electrodes are highlighted.

关键词： MXene 3D architectures Synthesis design Supercapacitor Energy storage

Beam Training and Tracking in mmWave Communication:A Survey

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China Communications 2024年第6期21卷 1-22页

作者： Wang yi wei Zhiqing Feng Zhiyong Yangtze Delta Region Institute(Quzhou) University of Electronic Science and Technology of ChinaQuzhou 324003China School of Information and Communication Engineering University of Electronic Science and Technology of ChinaChengdu 611731China Key Laboratory of Universal Wireless Communications Ministry of EducationBeijing University of Posts and TelecommunicationsBeijing 100876China

Communicating on millimeter wave(mmWave)bands is ushering in a new epoch of mobile communication which provides the availability of 10 Gbps high data rate ***,mmWave links are easily prone to short transmission range communication because of the serious free space path loss and the blockage by *** overcome these challenges,highly directional beams are exploited to achieve robust links by hybrid *** aligning the transmitter and receiver beams,*** training,is vitally important to high data rate ***,it may cause huge overhead which has negative effects on initial access,handover,and ***,the mobility patterns of users are complicated and dynamic,which may cause tracking error and large tracking *** efficient beam tracking method has a positive effect on sustaining robust *** article provides an overview of the beam training and tracking technologies on mmWave bands and reveals the insights for future research in the 6th Generation(6G)mobile ***,some open research problems are proposed to realize fast,accurate,and robust beam training and *** hope that this survey provides guidelines for the researchers in the area of mmWave communications.

关键词： 6G beam tracking beam training beamforming mmWave

NONMONOTONE LOCAL MINIMAX METHODS FOR FINDING MULTIPLE SADDLE POINTS

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Journal of Computational Mathematics 2024年第3期42卷 851-884页

作者： wei Liu Ziqing Xie Wenfan yi South China Research Center for Applied Mathematics and Interdisciplinary Studies South China Normal UniversityGuangzhou 510631China Key Laboratory of Computing and Stochastic Mathematics(Ministry of Education) Hunan Normal UniversityChangshaHunan 410081China Hunan Provincial Key Laboratory of Intelligent Information Processing and Applied Mathematics School of MathematicsHunan UniversityChangshaHunan 410082China

In this paper,by designing a normalized nonmonotone search strategy with the BarzilaiBorwein-type step-size,a novel local minimax method(LMM),which is a globally convergent iterative method,is proposed and analyzed to find multiple(unstable)saddle points of nonconvex functionals in Hilbert *** to traditional LMMs with monotone search strategies,this approach,which does not require strict decrease of the objective functional value at each iterative step,is observed to converge faster with less ***,based on a normalized iterative scheme coupled with a local peak selection that pulls the iterative point back onto the solution submanifold,by generalizing the Zhang-Hager(ZH)search strategy in the optimization theory to the LMM framework,a kind of normalized ZH-type nonmonotone step-size search strategy is introduced,and then a novel nonmonotone LMM is *** feasibility and global convergence results are rigorously carried out under the relaxation of the monotonicity for the functional at the iterative ***,in order to speed up the convergence of the nonmonotone LMM,a globally convergent Barzilai-Borwein-type LMM(GBBLMM)is presented by explicitly constructing the Barzilai-Borwein-type step-size as a trial step-size of the normalized ZH-type nonmonotone step-size search strategy in each ***,the GBBLMM algorithm is implemented to find multiple unstable solutions of two classes of semilinear elliptic boundary value problems with variational structures:one is the semilinear elliptic equations with the homogeneous Dirichlet boundary condition and another is the linear elliptic equations with semilinear Neumann boundary *** numerical results indicate that our approach is very effective and speeds up the LMMs significantly.

关键词： Multiple saddle points Local minimax method Barzilai-Borwein gradient method Normalized nonmonotone search strategy Global convergence

A Geometric Based Connection between Fractional Calculus and Fractal Functions

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Acta Mathematica Sinica,English Series 2024年第2期40卷 537-567页

作者： Yong Shun LIANG wei yi SU School of Mathematics and Statistic Nanjing University of Science and TechnologyNanjing 210094P.R.China Department of Mathematics Nanjing UniversityNanjing 210023P.R.China

Establishing the accurate relationship between fractional calculus and fractals is an important research content of fractional calculus *** the present paper,we investigate the relationship between fractional calculus and fractal functions,based only on fractal dimension *** dimension of the Riemann-Liouville fractional integral of continuous functions seems no more than fractal dimension of functions *** fractal dimension of the Riemann-Liouville fractional differential of continuous functions seems no less than fractal dimension of functions themselves when they *** further discussion,fractal dimension of the Riemann-Liouville fractional integral is at least linearly decreasing and fractal dimension of the Riemann-Liouville fractional differential is at most linearly increasing for the Holder continuous *** about other fractional calculus,such as the Weyl-Marchaud fractional derivative and the Weyl fractional integral has also been given *** work is helpful to reveal the mechanism of fractional calculus on continuous *** the same time,it provides some theoretical basis for the rationality of the definition of fractional *** is also helpful to reveal and explain the internal relationship between fractional calculus and fractals from the perspective of geometry.

关键词： Fractional calculus fractal functions fractal dimension fractional calculus equation relationship

A Semiparametric Additive-multiplicative Rates Model for the weighted Composite Endpoint of Recurrent and Terminal Events

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Acta Mathematica Sinica,English Series 2024年第4期40卷 985-999页

作者： yi DENG Qiang XIong Shu wei LI School of Economics and Statistics Guangzhou UniversityGuangzhou 510006P.R.China

Recurrent event data are commonly encountered in many scientific fields,including biomedical studies,clinical trials and epidemiological surveys,and many statistical methods have been proposed for their *** this paper,we consider to use a weighted composite endpoint of recurrent and terminal events,which is weighted by the severity of each event,to assess the overall effects of covariates on the two types of events.A flexible additive-multiplicative model incorporating both multiplicative and additive effects on the rate function is proposed to analyze such weighted composite event process,and more importantly,the dependence structure among the recurrent and terminal events is left *** the estimation,we construct the unbiased estimating equations by virtue of the inverse probability weighting technique,and the resulting estimators are shown to be consistent and asymptotically normal under some mild regularity *** evaluate the finite-sample performance of the proposed method via simulation studies and apply the proposed method to a set of real data arising from a bladder cancer study.

关键词： Additive-multiplicative rates model estimating equation recurrent events terminal event weighted composite endpoint

Odorant-binding protein 19 in Monochamus alternatus involved in the recognition of a volatile strongly emitted from ovipositing host pines

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Insect Science 2024年第1期31卷 134-146页

作者： Ruinan Yang Dongzhen Li Shancheng yi yi wei Manqun Wang Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory College of Plant Science and TechnologyHuazhong Agricultural UniversityWuhanChina Key Laboratory of Forest Protection of National Forestry and Grassland Administration Ecology and Nature Conservation InstituteChinese Academy of ForestryBeijingChina

Monochamus alternatus is the primary carrier of pine wood nematodes,which pose a serious threat to Pinus *** many *** emerging *** adults feed on heathy host pines,while matured adults transfer to stressed host pines for mating and *** odorant-binding proteins(OBPs)of *** have been proved to aid in the complex process of host *** clarify the corresponding relations between OBPs and pine volatiles,more OBPs need to be *** this research,MaltOBP19 showed a specific expression in the antennae and mouthparts of ***,and it was marked in 4 types of antenna sensilla by *** binding assays demonstrated the high binding affinity of MaltOBP19 with camphene and myrcene in *** Y-tube olfactory experiments,*** adults were attracted by camphene and RNAi of OBP19 via microinjection significantly decreased their attraction *** induced phobotaxis,but RNAi had no significant effect on this ***,we found that ingesting dsOBP19 produced by a bacteria-expressed system with a newly constructed vector could lead to the knockdown of *** results suggest that MaltOBP19 may play a role in the process of host conversion via the recognition of camphene,which has been identified to be strongly released in stressed host *** addition,it is proved that knockdown of OBP can be achieved by oral administration of bacteria-expressed double-stranded RNA in *** adults,providing a new perspective in the control of ***.

关键词： bacteria-expressed dsRNA camphene Japanese pine sawyer beetle MaltOBP19 RNAi stressed host pines

Vanadium(V) Complexes Containing Unsymmetrical N-Heterocyclic Carbene Ligands: Highly Efficient Synthesis and Catalytic Behavior towards Ethylene/Propylene Copolymerization

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Chinese Journal of Polymer Science 2024年第1期42卷 32-41,I0006页

作者： yi-Cong Wang Hui Zhat Pei-yi Cheng Shu Zhang Xiang-wei Liu yi-Xian Wu State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical TechnologyBejing 100029China

The highly efficient method has been developed for the synthesis of NHC·VOCl_(3) containing symmetrical or unsymmetrical Nheterocyclic carbene(NHC) ligands by the transmetallation reaction of NHC·AgCl with VOCl_(3).The total isolated yield of VOCl_(3)[1,3-(2,4,6-Me_(3)C_(6)H_(2))_(2)(NCH=)_(2)C:](V4') reached 86% by transmetallation reaction,which is much higher than that(48%) by direct coordination *** methodology has also been used to synthesize the novel vanadium complexes containing unsymmetrical NHC ligands of VOCl_(3)[PhCH_(2)NCH=CHNR)C:](V5',R=2,4,6-Me_(3)C_(6)H_(2);V6',R=2,4-Me_(2)-6-Ph-C_(6)H_(2);V7',R=2,6-^(i)Pr_(2)-C_(6)H_(3)) with high yield,which could not be obtained by direct coordination *** catalytic activity and copolymerization ability would be improved by introducing unsymmetrical NHC ligands due to their less steric bulky *** vanadium complex V5' containing unsymmetrical NHC ligand exhibits higher catalytic activity(3.7×10^(5)g_(copolymer)·mol^(-1) of V·h^(-1)) than that of V4' containing symmetrical NHC ***,the higher propylene incorporation ratio(45.6 mol%) in the copolymers of ethylene with propylene could be obtained by using V5' than that(39.9%) by using V4'.The results would provide a highly efficient strategy for the synthesis of early transition metal complexes containing versitile NHC ligands,affording the catalyst with both high catalytic activity and copolymerization ability for the synthesis of high performance polyolefin elastomers.

关键词： Vanadium complex N-heterocyclic carbene ligand Transmetallation reaction Copolymerization of ethylene with propylene

Superconducting,Topological,and Transport Properties of Kagome Metals CsTi_(3)Bi_(5)and RbTi_(3)Bi_(5)

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Research 2024年第2期2023卷 753-762页

作者： Xin-wei yi Zheng-wei Liao Jing-Yang You Bo Gu Gang Su School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China Department of Physics Faculty of ScienceNational University of Singapore117551Singapore Kavli Institute for Theoretical Sciences and CAS Center for Excellence in Topological Quantum ComputationUniversity of Chinese Academy of SciencesBeijing 100190China

The recently discovered ATi_(3)Bi_(5)(A=Cs,Rb)exhibit intriguing quantum phenomena including superconductivity,electronic nematicity,and abundant topological ***_(3)Bi_(5)present promising platforms for studying kagome superconductivity,band topology,and charge orders in parallel with *** this work,we comprehensively analyze various properties of ATi_(3)Bi_(5)covering superconductivity under pressure and doping,band topology under pressure,thermal conductivity,heat capacity,electrical resistance,and spin Hall conductivity(SHC)using first-principles *** superconducting transition temperature(Tc)of CsTi_(3)Bi_(5)and RbTi_(3)Bi_(5)at ambient pressure are about 1.85 and 1.92 *** subject to pressure,Tc of CsTi_(3)Bi_(5)exhibits a special valley and dome shape,which arises from quasi-two-dimensional compression to three-dimensional isotropic compression within the context of an overall decreasing ***,Tc of RbTi_(3)Bi_(5)can be effectively enhanced up to 3.09 K by tuning the kagome van Hove singularities(VHSs)and flat band through *** can also induce abundant topological surface states at the Fermi energy(EF)and tune VHSs across ***,our transport calculations are in excellent agreement with recent experiments,confirming the absence of charge density ***,SHC of CsTi_(3)Bi_(5)can reach up to 226h·(e·Ω·cm)^(-1)at *** work provides a timely and detailed analysis of the rich physical properties for ATi_(3)Bi_(5),offering valuable insights for further experimental verifications and investigations in this field.

关键词： doping superconductivity conductivity

High Speed Sintering:Assessing the Influence of Energy Input on Microstructure and Mechanical Properties of Polyether Block Amide(PEBA)Parts

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Chinese Journal of Polymer Science 2024年第5期42卷 675-682,I0004,I0010页

作者： Jiang-Tao Sun Zhi-Yong Fan yi-wei Mao wei Li wei Zhu Dao-Sheng Cai Qing-Song wei State Key Laboratory of Materials Processing and Die&Mould Technology Huazhong University of Science and TechnologyWuhan430074China State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan430074China National Engineering Research Centre for High Efficiency Grinding Hunan UniversityChangsha410082China Wuhan EasyMFG Technology CO. LTDWuhan430074China

High speed sintering,a new powder-bed fusion additive manufacturing technology,utilizes infrared lights(IR)to intensely heat and melt polymer *** presence of defects such as porosity,which is associated with particle coalescence,is highly dependdent on the level of energy *** study investigate the influcence of energy input on porosity and its subsequent effects on the mechanical properties and microstructures of PEBA *** parts were manufactured with a variety of lamp powers,resulting in a range of energy input levels spanning from low to ***,they underwent testing using Archimedes’method,followed by tensile *** porosity,mechanical characteristics,and energy input exhibit a strong correlation;inadequate energy input was the primary cause of pore *** the reduced IR light power resulted in the following outcomes:porosity,ultimate tensile strength,and elongation of 1.37%,7.6 MPa,and 194.2%,*** the energy input was further increased,the porosity was reduced to as low as 0.05%and the ultimate tensile strength and elongation were increased to their peak values of 233.8%and 9.1 MPa,respectively.

关键词： High speed sintering Additive manufacturing Energy input Powder bed fusion PEBA