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Nano Research 2024年第1期17卷 221-227页

作者： Yu Zhang Shuting Zhang Mengwei Yuan yufeng li Rong liu Caiyun Nan Chen Chen Engineering Research Center of Advanced Rare Earth Materials Department of ChemistryTsinghua UniversityBeijing 100084China Beijing Key Laboratory of Energy Conversion and Storage Materials Institution College of ChemistryBeijing Normal UniversityBeijing 100875China X-ray diffraction Lab Analytical and Testing CenterBeijing Normal UniversityBeijing 100875China

Co_(3)O_(4) is considered as one of promising cathode catalysts for lithium oxygen(li-O_(2))batteries,which contains both tetrahedral Co^(2+)sites(Co^(2+)Td)and octahedral Co^(3+)sites(Co^(3+)Oh).It is important to reveal the effect of optimal geometric configuration and oxidation state of cobalt ion in Co_(3)O_(4) to improve the performance of li-O_(2) batteries.Herein,through regulating the synthesis process,Co^(2+)and Co^(3+)sites in Co_(3)O_(4) were replaced with Zn and Al atoms to form materials with a unique Co site.The li-O_(2) batteries based on ZnCo_(2)O_(4) showed longer cycle life than that of CoAl_(2)O_(4),suggesting that in Co_(3)O_(4),the Co^(3+)Oh site is a relatively better geometric configuration than Co^(2+)Td site for li-O_(2) batteries.Theoretical calculations revealed that Co^(3+)Oh sites provide higher catalysis activity,regulating the adsorption energy of the intermediate liO_(2) and accelerating the kinetics of the reaction in batteries,which further leads to the change of the morphology of the discharge product and ultimately improves the electrochemical performance of the batteries.

关键词： lithium oxygen(li-O_(2))batteries geometrical configuration oxidation state lithium peroxide

A Random Fusion of Mix 3D and Polar Mix to Improve Semantic Segmentation Performance in 3D lidar Point Cloud

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Computer Modeling in Engineering & Sciences 2024年第7期140卷 845-862页

作者： Bo liu li Feng yufeng Chen School of Computer Science and Engineering Macao University of Science and TechnologyMacao999078China School of Computer Science and Artificial Intelligence Chaohu UniversityChaohu238000China Institute of Vehicle Information Control and Network Technology Hubei University of Automotive TechnologyShiyan442002China

This paper focuses on the effective utilization of data augmentation techniques for 3Dlidar point clouds to enhance the performance of neural network models.These point clouds,which represent spatial information through a collection of 3D coordinates,have found wide-ranging applications.Data augmentation has emerged as a potent solution to the challenges posed by limited labeled data and the need to enhance model generalization capabilities.Much of the existing research is devoted to crafting novel data augmentation methods specifically for 3D lidar point clouds.However,there has been a lack of focus on making the most of the numerous existing augmentation techniques.Addressing this deficiency,this research investigates the possibility of combining two fundamental data augmentation strategies.The paper introduces PolarMix andMix3D,two commonly employed augmentation techniques,and presents a new approach,named RandomFusion.Instead of using a fixed or predetermined combination of augmentation methods,RandomFusion randomly chooses one method from a pool of options for each instance or sample.This innovative data augmentation technique randomly augments each point in the point cloud with either PolarMix or Mix3D.The crux of this strategy is the random choice between PolarMix and Mix3Dfor the augmentation of each point within the point cloud data set.The results of the experiments conducted validate the efficacy of the RandomFusion strategy in enhancing the performance of neural network models for 3D lidar point cloud semantic segmentation tasks.This is achieved without compromising computational efficiency.By examining the potential of merging different augmentation techniques,the research contributes significantly to a more comprehensive understanding of how to utilize existing augmentation methods for 3D lidar point clouds.RandomFusion data augmentation technique offers a simple yet effective method to leverage the diversity of augmentation techniques and boost the robustness of models.The insights gained from this

关键词： 3D lidar point cloud data augmentation RandomFusion semantic segmentation

Self assembled electron blocking and lithiophilic interface towards dendrite-free solid-state lithium battery

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Chinese Chemical Letters 2024年第4期35卷 220-225页

作者： Caixia li Yi Qiu yufeng Zhao Wuliang Feng Institute for Sustainable Energy&College of Sciences Shanghai UniversityShanghai 200444China Key Laboratory of Advanced Energy Materials Chemistry(Ministry of Education) Nankai UniversityTianjin 300071China

The poor interfacial contact is one of the biggest challenges that solid-state lithium batteries suffer from.Reducing the solid-state electrolyte surface energy by transforming the interface from lithiophobic to lithiophilic is effective to promote the interfacial contact, but electronic conductive interphases usually increase the risk of electron attack, thus leading to uncontrollable li dendrite growth. Herein, we propose a self-assembled thermodynamic stable li I interphase to simultaneously improve the interfacial contact between the garnet electrolyte li_7La_(3)Zr_(2)O_(12)(LLZO) and li anode, and prohibit the electron attack. The direct contact between LLZO and li and the high temperature li melting process was ascribed to Zr4+reduction, which facilitated li dendrite formation and propagation. With the modification of the high lithiophilic I_(2) thin film, the area specific interfacial resistance of LLZO/li was reduced from 1525 Ω/cm^(2) to 57 Ω/cm^(2). More importantly, LLZO was protected from being reduced due to the outstanding electronic insulativity of the li I interphase, which leaded to a high critical current density of 1.2/7.0 m A/cm^(2) in the time/capacity-constant modes, respectively.

关键词： li_7La_(3)Zr_(2)O_(12) liI interphase Interfacial contact li dendrite Thermodynamic stable

Model reduction of fractional impedance spectra for time–frequency analysis of batteries, fuel cells, and supercapacitors

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Carbon Energy 2024年第1期6卷 108-141页

作者： Weiheng li Qiu-An Huang Yuxuan Bai Jia Wang linlin Wang Yuyu liu yufeng Zhao Xifei li Jiujun Zhang Institute for Sustainable Energy/College of Sciences Shanghai UniversityShanghaiChina Shanxi Key Laboratory of Nanomaterials and Nanotechnology School of Mechanical and Electrical EngineeringXi'an University of Architecture and TechnologyXi'anShaanxiChina Xi'an Key Laboratory of New Energy Materials and Devices School of Materials Science and EngineeringInstitute of Advanced Electrochemical EnergyXi'an University of TechnologyXi'anShaanxiChina

Joint time–frequency analysis is an emerging method for interpreting the underlying physics in fuel cells,batteries,and supercapacitors.To increase the reliability of time–frequency analysis,a theoretical correlation between frequency-domain stationary analysis and time-domain transient analysis is urgently required.The present work formularizes a thorough model reduction of fractional impedance spectra for electrochemical energy devices involving not only the model reduction from fractional-order models to integer-order models and from high-to low-order RC circuits but also insight into the evolution of the characteristic time constants during the whole reduction process.The following work has been carried out:(i)the model-reduction theory is addressed for typical Warburg elements and RC circuits based on the continued fraction expansion theory and the response error minimization technique,respectively;(ii)the order effect on the model reduction of typical Warburg elements is quantitatively evaluated by time–frequency analysis;(iii)the results of time–frequency analysis are confirmed to be useful to determine the reduction order in terms of the kinetic information needed to be captured;and(iv)the results of time–frequency analysis are validated for the model reduction of fractional impedance spectra for lithium-ion batteries,supercapacitors,and solid oxide fuel cells.In turn,the numerical validation has demonstrated the powerful function of the joint time–frequency analysis.The thorough model reduction of fractional impedance spectra addressed in the present work not only clarifies the relationship between time-domain transient analysis and frequency-domain stationary analysis but also enhances the reliability of the joint time–frequency analysis for electrochemical energy devices.

关键词： battery,fuel cell,supercapacitor fractional impedance spectroscopy model reduction time-frequency analysis

High-performance self-powered GaN/PEDOT:PSS hybrid heterojunction UV photodetector for optical communication

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Science China(Technological Sciences) 2024年第2期67卷 608-615页

作者： li Shan liU Zeng ZHANG Maolin YANG lili GUO yufeng TANG WeiHua College of Integrated Circuit Science and Engineering&National and Local Joint Engineering Laboratory for RF Integration and Micro-Packing Technologies Nanjing University of Posts and TelecommunicationsNanjing 210023China

Self-powered ultraviolet photodetectors(UVPDs)provide great possibility for the next-generation energy conservation optical communication technology;while the high photodetection performance at zero bias is still a tremendous challenge.Herein,ntype GaN film with Si-doping concentration of~1018cm^(-3)and p-type organic PEDOT:PSS were adopted to construct a planar hybrid heterojunction via the simple spin-coating method.Profited from typical type-Ⅱenergy band alignment and giant photovoltaic effect at GaN/PEDOT:PSS inorganic-organic interface,the fabricated UVPD achieved excellent self-powered photoelectrical properties in dual-band with large R of 0.96 A/W(2.8 A/W),superior D*of 5.7×1012Jones(1.7×10^(13)Jones),prominent EQE of 325%(1371%),high on/off ratio of 9.65×10^(3)(6.15×10^(3))and fast rise/decay time of 60.7/124.5 ms(30.9/26.7 ms)for UVA(UVC)band,as well as outstanding UV/visible rejection ratio and great detection repeatability.Functioned as an optical signal receiver,this designed self-powered UVPD decoded a message of“NJUPT”from a simple optical communication system.These results open a new avenue for GaN/PEDOT:PSS heterojunction in UV communications and related applications.

关键词： GaN UV photodetector self-powered heterojunction optical communication

Diffusion and reaction mechanism of limestone and quartz in fluxed iron ore pellet roasting process

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International Journal of Minerals,Metallurgy and Materials 2024年第3期31卷 485-497页

作者： yufeng Guo Jinlai Zhang Shuai Wang Jianjun Fan Haokun li Feng Chen Kuo liu lingzhi Yang School of Minerals Processing and Bioengineering Central South UniversityChangsha 410083China Technology Center Taiyuan Iron Steel(Group)Co.Ltd.(TISCO)Taiyuan 030003China

The increase to the proportion of fluxed pellets in the blast furnace burden is a useful way to reduce the carbon emissions in the ironmaking process.In this study,the interaction between calcium carbonate and iron ore powder and the mineralization mechanism of fluxed iron ore pellet in the roasting process were investigated through diffusion couple experiments.Scanning electron microscopy with energy dispersive spectroscopy was used to study the elements’diffusion and phase transformation during the roasting process.The results indicated that limestone decomposed into calcium oxide,and magnetite was oxidized to hematite at the early stage of preheating.With the increase in roasting temperature,the diffusion rate of Fe and Ca was obviously accelerated,while the diffusion rate of Si was relatively slow.The order of magnitude of interdiffusion coefficient of Fe_(2)O_(3)-CaO diffusion couple was 10^(−10) m^(2)·s^(−1) at a roasting temperature of 1200℃for 9 h.Ca_(2)Fe_(2)O_(5) was the initial product in the Fe_(2)O_(3)-CaO-SiO_(2) diffusion interface,and then Ca_(2)Fe_(2)O_(5) continued to react with Fe_(2)O_(3) to form CaFe_(2)O_(4).With the expansion of the diffusion region,the sillico-ferrite of calcium liquid phase was produced due to the melting of SiO_(2) into CaFe_(2)O_(4),which can strengthen the consolidation of fluxed pellets.Furthermore,andradite would be formed around a small part of quartz particles,which is also conducive to the consolidation of fluxed pellets.In addition,the principle diagram of limestone and quartz diffusion reaction in the process of fluxed pellet roasting was discussed.

关键词： fluxed iron ore pellet limestone hematite quartz diffusion reaction

F-doped orthorhombic Nb_(2)O_(5) exposed with 97% (100) facet for fast reversible liþ-Intercalation

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Green Energy & Environment 2024年第4期9卷 723-731页

作者： Xiaodi liu yufeng Tang Dan Zhang Guangyin liu Xinwei Luo Yi Shang Xiu li Jianmin Ma College of Chemistry and Pharmaceutical Engineering Nanyang Normal UniversityNanyang473061China School of Materials and Energy University of Electronic Science and Technology of ChinaChengdu611731China

Orthorhombic Nb_(2)O_(5)(T-Nb_(2)O_(5))is attractive for fast-charging li-ion batteries,but it is still hard to realize rapid charge transfer kinetics for li-ion storage.Herein,F-doped T-Nb_(2)O_(5) microﬂowers(F-Nb_(2)O_(5))are rationally synthesized through topotactic conversion.Specifically,F-Nb_(2)O_(5) are assembled by single-crystal nanoﬂakes with nearly 97%exposed(100)facet,which maximizes the exposure of the feasible li^(+)transport pathways along loosely packed 4g atomic layers to the electrolytes,thus effectively enhancing the li^(+)-intercalation performance.Besides,the band gap of F-Nb_(2)O_(5) is reduced to 2.87 eV due to the doping of F atoms,leading to enhanced electrical conductivity.The synergetic effects between tailored exposed crystal facets,F-doping,and ultrathin building blocks,speed up the li^(+)/electron transfer kinetics and improve the pseudocapacitive properties of F-Nb_(2)O_(5).Therefore,F-Nb_(2)O_(5) exhibit superior rate capability(210.8 and 164.9 mAh g^(-1) at 1 and 10 C,respectively)and good long-term 10 C cycling performance(132.7 mAh g^(-1) after 1500 cycles).

关键词： Exposed facets Orthorhombic Nb_(2)O_(5) F-doping Pseudocapacitive intercalation anode li-ion storage

Tribological performance of various metal-doped carbon dots as water-based lubricant additives and their potential application as additives of poly(ethylene glycol)

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Friction 2022年第5期10卷 688-705页

作者： Weiwei TANG Xuejun ZHU yufeng li School of Biological and Chemical Engineering Panzhihua UniversityPanzhihua 617000China

Advances in nano-lubricant additives are vital to the pursuit of energy efficiency and sustainable development.Carbon dots(CDs)have been widely investigated in the domain of lubricant additives owing to their extraordinary tribological properties,in particular,their friction-reducing and anti-wear properties.Metal-doped CDs are a new type of CDs,and their friction-reducing and anti-wear properties are attracting increasing attention.Therefore,a series of CDs doped with various divalent metal ions have been successfully synthesized via one-pot pyrolysis.The tribological properties of the synthesized CDs as water-based lubricant additives are in the following order:Zn-CDs>Cu-CDs>>Mg-CDs>Fe-CDs>U-CDs.Specifically,adding 1.0 wt%of Zn-CDs into water-based lubricant results in 62.5%friction and 81.8%wear reduction.Meanwhile,the load-carrying capacity of the water-based lubricant increases from 120 N to at least 500 N.Zn-CDs as an additive have long service life.Additionally,anion-tuned Zn-CDs fabricated via anion exchange exhibit promise as lubricant additives for poly(ethylene glycol).Based on the results of wear scar surface analyses,it is discovered that tribochemical films,primarily composed of iron oxides,nitrides,metal carbonates,zinc oxides,zinc carbonates,organic compounds,and embedded carbon cores,formed on the rubbing surfaces with a thickness of approximately 270 nm when Zn-CDs are used as additives.This film combined with the“ball-bearing”and third-particle effects of Zn-CDs contributed to excellent lubrication performance.

关键词： metal-doped carbon dots(CDs) water-based lubricant additives tribological performance lubrication mechanism

Orange-red emitting Sr_3LaTa_3O_(12):Sm^(3+) phosphors with perovskite structure and high thermal stability for w-LEDs

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Journal of Rare Earths 2024年第3期42卷 464-472,I0002页

作者： Xiaopeng Hu Anlin Zhang yufeng Du li Zhou Changlin li Jingjing lian Zhequan Zou Xuan Ouyang Bin Deng lianwu Xie Ruijin Yu College of Chemistry Biology and Environmental Engineering Xiangnan UniversityChenzhou423043China College of Sciences Central South University of Forestry and TechnologyChangsha410004China College of Chemistry&Pharmacy Northwest A&F UniversityYangling712100China Hunan Provincial Key Laboratory of Xiangnan Rare-Precious Metals Compounds Research and Application Xiangnan UniversityChenzhou423043China

A novel layered perovskite tantalate phosphor Sr_(3)LaTa_(3)O_(12):Sm^(3+)(SLTO:Sm^(3+)) with orange-red emission was obtained for the first time via the solid-phase synthetic method. The phase purity, surface morphology,element distribution and luminescent properties of the SLTO:xSm^(3+)(x= 0.01 mol%-0.30 mol%) phosphors were investigated. Under 408 nm excitation, the optimum doped SLTO:0.10Sm^(3+) phosphor emits orangered light at 598 nm with the highest emission peak(4G_(5/2)→6H_(7/2)). The critical energy transfer distance is 1.687 nm. The prepared SLTO:0.10Sm^(3+)phosphor has excellent thermal stability with temperature quenching temperature(T_(0.5)> 500 K) and high activation energy(E_(a)= 0.25 e V). Through calculation, the chromaticity coordinates of all samples are concentrated in the orange-red area, and the color purity reaches 99%. The fabricated white light-emitting diode(w-LED) has a good correlated color temperature(5132 K), a high R_(a)(89), and the CIE chromaticity coordinates(0.340, 0.327). Consequently, the superiority of orange-red-emitting tantalate SLTO:Sm^(3+) phosphors for w-LEDs is demonstrated.

关键词： Tantalate Sr_(3)LaTa_(3)O_(12) Sm^(3+) Luminescence LED Rare earths

Development of MoS_(2)-stainless steel catalyst by 3D printing for efficient destruction of organics via peroxymonosulfate activation

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Journal of Environmental Sciences 2024年第1期135卷 108-117页

作者： yufeng liu Jianhui Xu Xin Fu Pengxu Wang Dan li Yunfei Zhang Shenggui Chen Chunhui Zhang Peng liu School of Environment and Civil Engineering Dongguan University of TechnologyDongguan 523808China School of Art and Design Guangzhou Panyu PolytechnicGuangzhou 511483China Dongguan Institute of Science and Technology Innovation Dongguan University of TechnologyDongguan 523808China School of Mechanical Engineering Dongguan University of TechnologyDongguan 523808China

Herein,a novel MoS_(2)-stainless steel composite material was first synthetized via a 3D printing method(3DP MoS_(2)-SS)for peroxymonosulfate(PMS)activation and organics degradation.Compared with MoS_(2)-SS powder/PMS system(0.37 g/(m^(2)/min)),4.3-fold higher k_(FLO)/S_(BET)value was obtained in 3DP MoS_(2)-SS/PMS system(1.60 g/(m^(2)/min),resulting from the superior utilization of active sites.We observed that 3DP MoS_(2)-SS significantly outperformed the 3DP SS due to the enhanced electron transfer rate and increased active sites.Moreover,Mo^(4+)facilitated the Fe^(2+)/Fe^(3+)cycle,resulting in the rapid degradation of florfenicol(FLO).Quenching experiments and electron paramagnetic resonance spectra indicated that·OH,SO_(4)·^(-),O_(2)·^(-)and^(1)O_(2)were involved in the degradation of FLO.The effect of influencing factors on the degradation of FLO were evaluated,and the optimized degradation efficiency of 98.69%was achieved at 1 mM PMS and pH of 3.0.Six degradation products were detected by UPLC/MS analyses and several possible degradation pathways were proposed to be the cleavage of C-N bonds,dechlorination,hydrolysis,defluorination and hydroxylation.In addition,3DP MoS_(2)-SS/PMS system also demonstrated superior degradation performance for 2-chlorophenol,acetaminophen,ibuprofen and carbamazepine.This study provided deep insights into the MoS_(2)-SS catalyst prepared by 3DP technology for PMS activation and FLO-polluted water treatment.

关键词： 3D printing Stainless steel MoS_(2) Peroxymonosulfate activation Degradation mechanism