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Rheological Behaviors of Polymers with Nanoparticles Tethered at Each End

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Chinese Journal of Polymer Science 2024年第3期42卷 400-406,I0009页

作者： Song-Qi Zhang Wen-Qing Wang Jia-Ping lin li-quan Wang Shanghai Key Laboratory of Advanced Polymeric Materials Key Laboratory for Ultrafine Materials of Ministry of EducationSchool of Materials Science and EngineeringEast China University of Science and TechnologyShanghai 200237China

The polymer with nanoparticles tethered at each end is a unique model for unraveling the effect of chain ends on the polymer dynamics. We investigated the rheological behavior of this kind of polymer by using nonequilibrium molecular dynamics simulation. The effect of polymer lengths and nanoparticle radii on the complex moduli and viscosity was examined. The dependence of complex moduli on the frequency becomes less pronounced as the polymer is short or the nanoparticle is large. The shear thinning behavior was revealed for these systems, and the scaling exponent of complex viscosity with respect to the frequency was found to change from-1/2 to-3/4 as the polymer shortens or the nanoparticle enlarges. The rheological behavior was further explained by analyzing the mean square distance of nanoparticles. The simulation results were compared with the existing experimental finding, showing an agreement. The work provides information for understanding the chain end effect on polymer rheology.

关键词： Polymer rheology Modulus Viscosity Molecular dynamics

Molecular investigation into the transformation of recalcitrant dissolved organic sulfur in refinery sour water during stripping process

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Petroleum Science 2024年第3期21卷 2112-2119页

作者： Yu-Guo li Chen He Chun-Mao Chen Fan liu quan Shi State Key Laboratory of Heavy Oil Processing China University of PetroleumBeijing 102249China State Key Laboratory of Coal Mining and Clean Utilization Beijing 100013China PetroChina Ningxia Petrochemical Company Yinchuan 750021NingxiaChina

Refinery sour water primarily originates from the tops of towers in various units and coker condensate,and cannot be discharged directly to a wastewater treatment plant due to high levels of chemical oxygen demand(COD)and organic sulfur *** after the recovery of H_(2)S from the sour water by the stripping process,the effluent still contains a high concentration of dissolved organic sulfur(DOS),which can have a huge bad *** chemical composition of dissolved organic matter(DOM)in refinery wastewater has been extensively studied,the investigation of recalcitrant DOS from sour waters remains *** the present study,chemical composition of sour water DOMs(especially DOS)was investigated using fluorescence spectroscopy(excitation-emission matrix,EEM)and mass spectrometry,including gas chromatography-mass spectrometry(GC-MS)and high-resolution Orbitrap *** GC-MS and EEM results showed that volatile and low-aromaticity compounds were effectively removed during the stripping process,while compounds with high hydrophilicity and humification degree were found to be more *** Orbitrap MS results showed that weak-polar oxygenated sulfur compounds were easier to be removed than oxygenated ***,the effluent still contained significant amounts of sulfur-containing compounds with multiple sulfur atoms,particularly in the form of highly unsaturated and aromatic *** Orbitrap MS/MS results of CHOS-containing compounds from the effluent indicate that the sulfur atoms may exist as sulfonates,disulfide bonds,*** the composition and structure of sour water DOS is crucial for the development of effective treatment processes that can target polysulfide compounds and minimize their impact on the environment.

关键词： Molecular transformation Dissolved organic sulfur Stripping process Refinery sourwater Orbitrap MS

Dual-aligned porous electrodes for enhanced hydrogen evolution in alkaline water electrolysis

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Nano Research 2024年第5期17卷 3835-3843页

作者： Yuqi Zhang Wenzhi Cui Longjian li Chongbo Wang Chen Zhan Xiaojun quan School of Energy and Power Engineering Chongqing UniversityChongqing 400030China Key Laboratory of Low-grade Energy Utilization Technologies and Systems Chongqing UniversityChongqing 400030China School of Mechanical Engineering Shanghai Jiao-Tong UniversityShanghai 200240China

The efficiency of water electrolysis is significantly affected by the bubbles on the surface and inside the *** enhance the gas-liquid transfer within the porous electrodes,we developed an innovative design termed dual-aligned porous electrode(D-APE),achieved by integrating magnetic alignment with freeze casting *** paper investigates the hydrogen evolution performance of porous electrodes prepared using four different methods:evaporation,magnetic-aligned evaporation,freeze casting,and dual-aligned *** findings demonstrate that the magnetic-aligned process effectively alters the electrode structure,resulting in improved hydrogen evolution ***,among all the examined electrodes,the D-APE exhibits the highest hydrogen evolution performance,with further enhancements observed with prolonged the time of magnetic ***,a comparison is made between electrodes prepared using the freeze casting method and the dual-aligned method at various *** results show that the thinner D-APE exhibits excellent hydrogen evolution performance at high current ***,the D-APE demonstrates significantly improved material utilization rates compared to the conventional freeze casting method,offering promising prospects for enhancing the efficiency of water electrolysis.

关键词： hydrogen evolution reaction dual-aligned magnetic-aligned freeze casting

Investigation of gravity influence on EOR and CO_(2) geological storage based on pore-scale simulation

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Petroleum Science 2024年第2期21卷 987-1001页

作者： Yong-Mao Hao Gui-Cheng Wu Zong-Fa li Zhong-Hui Wu Yong-quan Sun Ran liu Xing-Xing li Bo-Xin Pang Nan li Key Laboratory of Unconventional Oil&Gas Development(China University of Petroleum(East China)) Ministry of EducationQingdao266580ShandongChina School of Petroleum Engineering China University of Petroleum(East China)Qingdao266580ShandongChina School of Petroleum Engineering Yangtze UniversityWuhan430100HubeiChina Dongsheng Jinggong Petroleum Development Group Co. LtdShengli Oilfield CompanySINOPECDongying257001ShandongChina

Gravity assistance is a critical factor influencing CO_(2)-Oil mixing and miscible flow during EOR and CO_(2)geological *** on the Navier-Stokes equation,component mass conservation equation,and fluid property-composition relationship,a mathematical model for pore-scale CO_(2) injection in oilsaturated porous media was developed in this *** model can reflect the effects of gravity assistance,component diffusion,fluid density variation,and velocity change on EOR and CO_(2) *** nonhomogeneous porous media,the gravity influence and large density difference help to minimize the velocity difference between the main flow path and the surrounding area,thus improving the oil recovery and CO_(2) *** CO_(2) injection angles and oil-CO_(2) density differences can increase the oil recovery by 22.6% and 4.2%,respectively,and increase CO_(2) storage by 37.9% and 4.7%,*** diffusion facilitates the transportation of the oil components from the low-velocity region to the main flow path,thereby reducing the oil/CO_(2) concentration difference within the porous *** diffusion can increase oil recovery and CO_(2) storage by 5.7% and 6.9%,*** addition,combined with the component diffusion,a low CO_(2) injection rate creates a more uniform spatial distribution of the oil/CO_(2) component,resulting in increases of 9.5% oil recovery and 15.7% CO_(2) storage,*** study provides theoretical support for improving the geological CO_(2) storage and EOR processes.

关键词： Gravity Flow simulation CO_(2)-oil mixing Enhanced oil recovery(EOR) Geological storage

Sliced Average Variance Estimation for Tensor Data

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Acta Mathematicae Applicatae Sinica 2024年第3期40卷 630-655页

作者： Chuan-quan li Pei-wen XIAO Chao YING Xiao-hui liU School of Statistics Jiangxi University of Finance and EconomicsNanchang 330013China Key Laboratory of Data Science in Finance and Economics Jiangxi University of Finance and EconomicsNanchang 330013China Biostatistics and Medical Informatics University of Wisconsin MadisonMadison 53726USA

Tensor data have been widely used in many fields,e.g.,modern biomedical imaging,chemometrics,and economics,but often suffer from some common issues as in high dimensional *** to find their low-dimensional latent structure has been of great interest for *** this end,we develop two efficient tensor sufficient dimension reduction methods based on the sliced average variance estimation(SAVE)to estimate the corresponding dimension reduction *** first one,entitled tensor sliced average variance estimation(TSAVE),works well when the response is discrete or takes finite values,but is not■consistent for continuous response;the second one,named bias-correction tensor sliced average variance estimation(CTSAVE),is a de-biased version of the TSAVE *** asymptotic properties of both methods are derived under mild *** and real data examples are also provided to show the superiority of the efficiency of the developed methods.

关键词： tensor data sliced average variance estimation sufficient dimension reduction central subspace

Supermassive black holes triggered by QCD axion bubbles

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Communications in Theoretical Physics 2024年第5期76卷 134-139页

作者： Hai-Jun li Ying-quan Peng Wei Chao Yu-Feng Zhou Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China Center for Advanced quantum Studies Department of PhysicsBeijing Normal UniversityBeijing 100875China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUCASHangzhou 310024China International Centre for Theoretical Physics Asia-Pacific Beijing/HangzhouChina

Supermassive black holes(SMBHs)are ubiquitous in the center of galaxies,although the origin of their massive seeds is still *** this paper,we investigate the formation of SMBHs from the quantum chromodynamics(QCD)axion *** this case,primordial black holes(PBHs)are considered as the seeds of SMBHs,which are generated from the QCD axion bubbles due to an explicit Peccei–Quinn(PQ)symmetry breaking after *** QCD axion bubbles are formed when the QCD axion starts to oscillate during the QCD phase *** consider a general case in which the axion bubbles are formed with the bubble effective angle θ_(eff)∈(0,π],leading to the minimum PBH mass∼■(10^(4)−10^(7))M⊙for the axion decay constant f_(a)∼■(10^(16))*** PBHs at this mass region may account for the seeds of SMBHs.

关键词： supermassive black holes primordial black holes quantum chromodynamics axion

Design and modification of metal sulfide-based catalysts for lithiumsulfur batteries

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Particuology 2024年第3期86卷 86-100页

作者： Yufei Zhao Chuannan Geng li Wang Haotian Yang Wei Lv quan-Hong Yang Nanoyang Group State Key Laboratory of Chemical EngineeringSchool of Chemical Engineering and TechnologyNational Industry-Education Integration Platform of Energy Storageand Collaborative Innovation Center of Chemical Science and Engineering(Tianjin)Tianjin UniversityTianjin300072China Shenzhen Geim Graphene Center Engineering Laboratory for Functionalized Carbon MaterialsTsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhen518055China Haihe Laboratory of Sustainable Chemical Transformations Tianjin300192China Joint School of National University of Singapore and Tianjin University International Campus of Tianjin UniversityFuzhou350207China

Metal sulfide(MS)have good conductivity,strong adsorption ability,and excellent catalytic activity for the conversion of sulfur species,and thus,show great promise as the catalysts in lieS ***,the relationship between their properties and electrochemical performance is still ***,further in-depth discussions are required to improve their design in li-S *** review systematically summarizes the basic structural and electrochemical properties of MSs and highlights the advantages that guarantee them as high-performance catalysts in li-S ***,various modification strategies for MSs to enhance the catalytic activity,efficiency,and stability are also *** last,future opportunities for MS catalysts in li-S batteries are proposed.

关键词： lithium-sulfur battery Metal sulfide Catalysis

Achieving high carrier mobility and low lattice thermal conductivity in GeTe-based alloys by cationic/anionic co-doping

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Rare Metals 2024年第6期43卷 2784-2795页

作者： Xiao-Qiang Wang Xiao-quan Hu Jun-Yan lin Chu-Bin li Xiao-Tong Yu Qi-Yong Chen li-li Xi Qi-Shuo Yang Han li Ji-Ye Zhang Shuan-Kui li Kai Guo School of Physics and Materials Science Guangzhou UniversityGuangzhou 510006China Research Center for Advanced Information Materials(CAIM) Huangpu Research&Graduate School of Guangzhou UniversitySino-Singapore Guangzhou Knowledge CityGuangzhou510555China School of Materials Science and Engineering Shanghai UniversityShanghai 200444China Materials Genome Institute Shanghai UniversityShanghai 200444China School of Mechanical and Mining Engineering University of QueenslandBrisbaneQLD 4072Australia Key Laboratory of Si-Based Information Materials&Devices and Integrated Circuits Design Department of Education of Guangdong ProvinceGuangzhou 510006China

TheⅣ-Ⅵcompound GeTe is considered as a promising alternative to the toxic PbTe for high-efficiency mid-temperature thermoelectric ***,pristine GeTe suffers from a high concentration of Ge vacancies,resulting in an excessively high hole concentration(>1×10^(21)cm^(-3)),which greatly limits its thermoelectric *** address this issue,CuBiTe_(2)alloying is introduced to increase the formation energy of Ge vacancies in GeTe,thereby inhibiting the high carrier *** carrier scattering caused by the electronegativity difference between different elements is suppressed due to the similar electronegativity of Cu and Ge atoms.A relatively high hole mobility is obtained,which ultimately leads to a high power ***,by introducing Se as an alloying element at the anionic site in GeTe,dense point defects with mass/strainfield fluctuations are *** contributes to the strengthening of phonon scattering,thereby reducing the lattice thermal conductivity from 1.44 W·m^(-1)·K^(-1)for pristine GeTe to 0.28 W·m^(-1)·K^(-1)for Ge_(0.95)Cu_(0.05)Bi_(0.05)Te_(0.9)Se_(0.15)compound at 623 K.

关键词： GeTe Carrier mobility CuBiTe_(2)alloying Lattice thermal conductivity Thermoelectric properties

Asymmetric frequency multiplexing topological devices based on a floating edge band

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Photonics Research 2024年第6期12卷 1201-1212页

作者： JIAJUN MA CHUNMEI OUYANG YUTING YANG DONGYANG WANG HONGYI li li NIU YI liU quan XU YANFENG li ZHEN TIAN JIAGUANG HAN WEIli ZHANG Center for Terahertz Waves and College of Precision Instrument and Optoelectronics Engineering and Key Laboratory of Optoelectronics Information and TechnologyTianjin UniversityTianjin 300072China School of Materials Science and Physics China University of Mining and TechnologyXuzhou 221116China Optoelectronics Research Centre University of SouthamptonSouthampton SO171BJUK Guangxi Key Laboratory of Optoelectronic Information Processing School of Optoelectronic EngineeringGuilin University of Electronic TechnologyGuilin 541004China School of Electrical and Computer Engineering Oklahoma State UniversityStillwaterOklahoma 74078USA

Topological photonics provides a platform for robust energy transport regardless of sharp corners and ***,the frequency multiplexing topological devices have attracted much attention due to the ability to separate optical signals by wavelength and hence the potential application in optical communication *** frequency multiplexing topological devices are generally based on the slow light ***,the resulting static local spatial mode or finely tuned flat band has zero-group velocity,making it difficult for both experimental excitation and channel ***,we propose and experimentally demonstrate an alternative prototype of asymmetric frequency multiplexing devices including a topological rainbow and frequency router based on floating topological edge mode(instead of localized ones);hence the multiple wavelength channels can be collectively excited with a point source and efficiently routed to separate output *** channel separation in our design is achieved by gradually tuning the band gap truncation on a topological edge band over a wide range of frequencies.A crucial feature lies in that the topological edge band is detached from bulk states and floating within the upper and lower photonic band *** interestingly,due to the sandwiched morphology of the edge band,the top and bottom band gaps will each truncate into transport channels that support topological propagation towards opposite directions,and the asymmetrical transportation is realized for the frequency multiplexing topological devices.

关键词： tuning floating hence