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Tetrathiafulvalene esters with high redox potentials and improved solubilities for non-aqueous redox flow battery applications

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Green Energy & Environment 2024年第5期9卷 899-908页

作者： Weikang Hu Jiaqi Xu Nanjie Chen Zongcai Deng Yuekun Lai Dongyang Chen college of Materials Science and engineering Fuzhou UniversityFuzhou350116China college of Chemical engineering Fuzhou UniversityFuzhou350116China

The exploitation of high performance redox-active substances is critically important for the development of non-aqueous redoxﬂow batteries.Herein,three tetrathiofulvalene(TTF)derivatives with different substitution groups,namely TTF diethyl ester(TTFDE),TTF tetramethyl ester(TTFTM),and TTF tetraethyl ester(TTFTE),are prepared and their energy storage properties are evaluated.It has been found that the redox potential and solubility of these TTF derivatives in conventional carbonate electrolytes increases with the number of ester groups.The battery with a catholyte of 0.2 mol L^(-1) of TTFTE delivers a speciﬁc capacity of more than 10 Ah L^(-1) at the current density of 0.5 C with two discharge voltage platforms locating at as high as 3.85 and 3.60 V vs.Li/Liþ.Its capacity retention can be improved from 2.34 Ah L^(-1) to 3.60 Ah L^(-1) after 100 cycles by the use of an anion exchange membrane to block the crossover of TTF species.The excellent cycling stability of the TIF esters is supported by their well-delocalized electrons,as revealed by the density function theory calculations.Therefore,the introduction of more and larger electron-withdrawing groups is a promising strategy to simultaneously increase the redox-potential and solubility of redox-active ma-terials for non-aqueous redoxﬂow batteries.

关键词： Non-aqueous redox flow batteries Tetrathiofulvarene Redox potential Solubility Substituent effect

A new navigation approach of terrain contour matching based on 3-D terrain reconstruction from onboard image sequence

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Science China(Technological Sciences) 2010年第5期53卷 1176-1183页

作者： LI LiChun1,2,YU QiFeng2,SHANG Yang2,YUAN Yun2,LU HongWei3 & LIU XiaoLin4 1 Beijing aerospace Control Center,Beijing 100094,China 2 college of aerospace and Material engineering,National University of Defense Technology,Changsha 410073,China 3 Equipment Research Institute of PLA’s Second Artillery,Beijing 100085,China 4 college of Mechatronic engineering and Automation,National University of Defense Technology,Changsha 410073,China Beijing aerospace Control Center Beijing China college of aerospace and Material engineering National University of Defense Technology Changsha China Equipment Research Institute of PLA’s Second Artillery Beijing China college of Mechatronic engineering and Automation National University of Defense Technology Changsha China

This article presents a passive navigation method of terrain contour matching by reconstructing the 3-D terrain from the image sequence(acquired by the onboard camera).To achieve automation and simultaneity of the image sequence processing for navigation,a correspondence registration method based on control points tracking is proposed which tracks the sparse control points through the whole image sequence and uses them as correspondence in the relation geometry solution.Besides,a key frame selection method based on the images overlapping ratio and intersecting angles is explored,thereafter the requirement for the camera system configuration is provided.The proposed method also includes an optimal local homography estimating algorithm according to the control points,which helps correctly predict points to be matched and their speed corresponding.Consequently,the real-time 3-D terrain of the trajectory thus reconstructed is matched with the referenced terrain map,and the result of which provides navigating information.The digital simulation experiment and the real image based experiment have verified the proposed method.

关键词： terrain contour matching vision-based navigation 3-D reconstruction control points key frame registration optimal local homography

Airfoil friction drag reduction based on grid-type and super-dense array plasma actuators

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Plasma Science and Technology 2024年第2期26卷 94-103页

作者：方子淇宗豪华吴云梁华苏志 School of aerospace engineering Xi'an Jiaotong UniversityXi'an 710049People's Republic of China School of Mechanical engineering Xi'an Jiaotong UniversityXi'an 710049People's Republic of China National Key Lab of aerospace Power System and Plasma Technology Air Force Engineering UniversityXi'an 710038People's Republic of China

To improve the cruise flight performance of aircraft, two new configurations of plasma actuators(grid-type and super-dense array) were investigated to reduce the turbulent skin friction drag of a low-speed airfoil. The induced jet characteristics of the two actuators in quiescent air were diagnosed with high-speed particle image velocimetry(PIV), and their drag reduction efficiencies were examined under different operating conditions in a wind tunnel. The results showed that the grid-type plasma actuator was capable of producing a wall-normal jet array(peak magnitude: 1.07 m/s) similar to that generated in a micro-blowing technique, while the superdense array plasma actuator created a wavy wall-parallel jet(magnitude: 0.94 m/s) due to the discrete spanwise electrostatic forces. Under a comparable electrical power consumption level,the super-dense array plasma actuator array significantly outperformed the grid-type configuration,reducing the total airfoil friction drag by approximately 22% at a free-stream velocity of 20 m/s.The magnitude of drag reduction was proportional to the dimensionless jet velocity ratio(r), and a threshold r = 0.014 existed under which little impact on airfoil drag could be discerned.

关键词： plasma actuator flow control drag reduction airfoil

Enhanced photocatalytic performance of Bi_(2)O_(2)CO_(3)/Bi_(4)O_(5)Br_(2)/reduced graphene oxide Z-schemehe terojunction via a one-pot room-temperature synthesis

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Journal of Environmental Sciences 2024年第4期138卷 418-427页

作者： Xiaoge Wu Lei Yan Rongrong Qin Qikai Zhang Wei Yang Xiaozhi Wang Yongcai Zhang Min Luo Jianhua Hou college of Environmental Science and engineering Yangzhou UniversityYangzhouJiangsu 225009China Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization Nanjing 210095China Beijing Xinfeng aerospace Equipment Co. Ltd.Beijing 100854China Beijing System Design Institute of Electro-Mechanic engineering Beijing 100005China college of Chemistry and Chemical engineering Ningxia UniversityYinchuanNingxia 750021China

Bi_(2)O_(2)CO_(3)(BOC)/Bi_(4)O_5Br_(2)(BOB)/reduced graphene oxide(rGO)Z-scheme heterojunction with promising photocatalytic properties was synthesized via a facile one-pot room-temperature method.Ultra-thin nanosheets of BOC and BOB were grown in situ on r GO.The formed 2D/2D direct Z-scheme heterojunction of BOC/BOB with oxygen vacancies(OVs)effectively leads to lower negative electron reduction potential of BOB as well as higher positive hole oxidation potential of BOC,showing improved reduction/oxidation ability.Particularly,rGO is an acceptor of the electrons from the conduction band of BOC.Its dual roles significantly improve the transfer performance of photo-induced charge carriers and accelerate their separation.With layered nanosheet structure,rich OVs,high specific surface area,and increased utilization efficiency of visible light,the multiple synergistic effects of BOC/BOB/rGO can achieve effective generation and separation of the electron-holes,thereby generating more·O_(2)^(-)and h^(+).The photocatalytic reduction efficiency of CO_(2)to CO(12.91μmol/(g·hr))is three times higher than that of BOC(4.18μmol/(g·hr)).Moreover,it also achieved almost 100%removal of Rhodamine B and cyanobacterial cells within 2 hours.

关键词： Bi_(2)O_(2)CO_(3) Bi_(4)O_(5)Br_(2) Reduced graphene oxide Z-scheme heterojunction Photocatalysis CO_(2)reduction

Novel sandwich structured glass fiber Cloth/Poly(ethylene oxide)-MXene composite electrolyte

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Nano Materials Science 2024年第1期6卷 60-67页

作者： Yu-Qin Mao Guang-He Dong Wei-Bin Zhu Yuan-Qing Li Pei Huang Shao-Yun Fu college of aerospace engineering Chongqing UniversityChongqing400044China State Key Laboratory of Power Transmission Equipment and System Security and New Technology Chongqing UniversityChongqing400044China

Recently,poly(ethylene oxide)(PEO)-based solid polymer electrolytes have been attracting great attention,and efforts are currently underway to develop PEO-based composite electrolytes for next generation high performance all-solid-state lithium metal batteries.In this article,a novel sandwich structured solid-state PEO composite electrolyte is developed for high performance all-solid-state lithium metal batteries.The PEO-based composite electrolyte is fabricated by hot-pressing PEO,LiTFSI and Ti_(3)C_(2)T_(x) MXene nanosheets into glass fiber cloth(GFC).The as-prepared GFC@PEO-MXene electrolyte shows high mechanical properties,good electrochemical stability,and high lithium-ion migration number,which indicates an obvious synergistic effect from the microscale GFC and the nanoscale MXene.Such as,the GFC@PEO-1 wt%MXene electrolyte shows a high tensile strength of 43.43 MPa and an impressive Young's modulus of 496 MPa,which are increased by 1205%and 6048%over those of PEO.Meanwhile,the ionic conductivity of GFC@PEO-1 wt%MXene at 60℃ reaches 5.01×10^(-2) S m^(-1),which is increased by around 200%compared with that of GFC@PEO electrolyte.In addition,the Li/Li symmetric battery based on GFC@PEO-1 wt%MXene electrolyte shows an excellent cycling stability over 800 h(0.3 mA cm^(-2),0.3 mAh cm^(-2)),which is obviously longer than that based on PEO and GFC@PEO electrolytes due to the better compatibility of GFC@PEO-1 wt%MXene electrolyte with Li anode.Furthermore,the solid-state Li/LiFePO_(4) battery with GFC@PEO-1 wt%MXene as electrolyte demonstrates a high capacity of 110.2–166.1 mAh g^(-1) in a wide temperature range of 25–60C,and an excellent capacity retention rate.The developed sandwich structured GFC@PEO-1 wt%MXene electrolyte with the excellent overall performance is promising for next generation high performance all-solid-state lithium metal batteries.

关键词： Solid polymer electrolyte Ti_(3)C_(2)T_(x)MXene Poly(ethylene oxide) Glass fiber cloth All-solid-state Li metal Battery

Thermogalvanic hydrogel-based e-skin for self-powered on-body dual-modal temperature and strain sensing

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Microsystems & Nanoengineering 2024年第2期10卷 293-302页

作者： Zhaosu Wang Ning Li Xinru Yang Zhiyi Zhang Hulin Zhang Xiaojing Cui college of Electronic Information and Optical engineering Taiyuan University of TechnologyTaiyuan030024China college of Materials Science and engineering Taiyuan University of TechnologyTaiyuan030024China School of Physics and Information engineering Shanxi Normal UniversityTaiyuan030031China

Sensing of both temperature and strain is crucial for various diagnostic and therapeutic purposes.Here,we present a novel hydrogel-based electronic skin(e-skin)capable of dual-mode sensing of temperature and strain.The thermocouple ion selected for this study is the iodine/triiodide(I−/I3−)redox couple,which is a common component in everyday disinfectants.By leveraging the thermoelectric conversion in conjunction with the inherent piezoresistive effect of a gel electrolyte,self-powered sensing is achieved by utilizing the temperature difference between the human body and the external environment.The composite hydrogels synthesized from polyvinyl alcohol(PVA)monomers using a simple freeze‒thaw method exhibit remarkable flexibility,extensibility,and adaptability to human tissue.The incorporation of zwitterions further augments the resistance of the hydrogel to dehydration and low temperatures,allowing maintenance of more than 90%of its weight after 48 h in the air.Given its robust thermal current response,the hydrogel was encapsulated and then integrated onto various areas of the human body,including the cheeks,fingers,and elbows.Furthermore,the detection of the head-down state and the monitoring of foot movements demonstrate the promising application of the hydrogel in supervising the neck posture of sedentary office workers and the activity status.The successful demonstration of self-powered on-body temperature and strain sensing opens up new possibilities for wearable intelligent electronics and robotics.

关键词： hydrogel modal utilizing

Formation mechanism of Fe-based amorphous powders produced by spark erosion

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Journal of Materials Science & Technology 2024年第3期170卷 33-46页

作者： Chekai Liu Ran Li Jiazi Bi Ding Ma Xiaobin Liu Tao Zhang School of Materials Science and engineering Key Laboratory of Aerospace Materials and Performance(Ministry of Education)Beihang UniversityBeijing 100191China

Spark erosion is a convenient,flexible,and low-cost method to quickly produce fine powders of metals,alloys,and semiconductors in size ranging from nearly a hundred micrometers to submicrometer by repetitive spark discharges.Due to the complexity of the powder-forming journey,normally accompanied by high temperature,high pressure,decomposition,diffusion and rapid quenching caused by discharge plasma,the mechanisms of powder formation and possible contaminant infiltration are still controversial,posing a significant challenge to control particle size and chemical composition of the powder produced by this method.In this study,Fe-based amorphous powders in different particle-size distributions with high sphericity were fabricated by spark erosion under different discharge-energy conditions.The max-imum particle size of the resultant powders can be correlated with discharge parameters,crater depth,and crater radius,respectively.A multi-ring-breakup model is proposed to reveal the particle-size distribution of the powder formed from the electrode melt under a single-pulse discharge.Furthermore,a dielectric-element infiltration model is provided to quantitatively evaluate the infiltration mass ratio of the contaminant elements,stemming from the decomposed products of dielectric liquid,in the resultant powder with different particle sizes.The models verified through the experimental data are significant for the development of high-performance fine Fe-based amorphous powder with controlled particle size and chemical composition.

关键词： Amorphous alloy Particle Spark erosion Infiltration Modeling

Improved spatio-temporal alignment measurement method for hull deformation

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Journal of Systems engineering and Electronics 2024年第2期35卷 485-494页

作者： XU Dongsheng YU Yuanjin ZHANG Xiaoli PENG Xiafu School of Automation Beijing Institute of TechnologyBeijing 100081China School of aerospace engineering Xiamen UniversityXiamen 361005China

In this paper,an improved spatio-temporal alignment measurement method is presented to address the inertial matching measurement of hull deformation under the coexistence of time delay and large misalignment angle.Large misalignment angle and time delay often occur simultaneously and bring great challenges to the accurate measurement of hull deformation in space and time.The proposed method utilizes coarse alignment with large misalignment angle and time delay estimation of inertial measurement unit modeling to establish a brand-new spatiotemporal aligned hull deformation measurement model.In addition,two-step loop control is designed to ensure the accurate description of dynamic deformation angle and static deformation angle by the time-space alignment method of hull deformation.The experiments illustrate that the proposed method can effectively measure the hull deformation angle when time delay and large misalignment angle coexist.

关键词： inertial measurement spatio-temporal alignment hull deformation

Effect of neutral polymeric bonding agent on tensile mechanical properties and damage evolution of NEPE propellant

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Defence Technology（防务技术） 2024年第2期32卷 357-367页

作者： M.Wubuliaisan Yanqing Wu Xiao Hou Kun Yang Hongzheng Duan Xinmei Yin State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081PR China The Fourth Institute of China aerospace Science and Technology Corporation Xi'an710025PR China School of aerospace engineering Beijing Institute of TechnologyBeijing100081PR China Science and Technology on aerospace Chemical Power Laboratory Hubei Institute of Aerospace ChemotechnologyHubei441003PR China

Introducing Neutral Polymeric bonding agents(NPBA) into the Nitrate Ester Plasticized Polyether(NEPE)propellant could improve the adhesion between filler/matrix interface, thereby contributing to the development of new generations of the NEPE propellant with better mechanical properties. Therefore,understanding the effects of NPBA on the deformation and damage evolution of the NEPE propellant is fundamental to material design and applications. This paper studies the uniaxial tensile and stress relaxation responses of the NEPE propellant with different amounts of NPBA. The damage evolution in terms of interface debonding is further investigated using a cohesive-zone model(CZM). Experimental results show that the initial modulus and strength of the NEPE propellant increase with the increasing amount of NPBA while the elongation decreases. Meanwhile, the relaxation rate slows down and a higher long-term equilibrium modulus is reached. Experimental and numerical analyses indicate that interface debonding and crack propagation along filler-matrix interface are the dominant damage mechanism for the samples with a low amount of NPBA, while damage localization and crack advancement through the matrix are predominant for the ones with a high amount of NPBA. Finally, crosslinking density tests and simulation results also show that the effect of the bonding agent is interfacial rather than due to the overall crosslinking density change of the binder.

关键词： Solid propellant Bonding agent Mechanical properties Damage evolution Cohesive-zone model Interface debonding