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Enhancing lithium-ion and electric conductive li_(2)FeSiO_(4)cathode through in situ boron-doping and carbon-coating strategy

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Rare Metals 2022年第12期41卷 4055-4064页

作者： hao-xiang li Jia-Hui Zhu Xiao-Bing Huang Tao Zhou Yu-Rong Ren Hunan Provincial Key Laboratory of Chemical Power Sources College of Chemistry and Chemical EngineeringCentral South UniversityChangsha 410083China Hunan Provincial Key Laboratory of Water Treatment Functional Materials Hunan Provincial Key Laboratory for Control Technology of Distributed Electric Propulsion AircraftCollege of Chemistry and Materials EngineeringHunan University of Arts and ScienceChangde 415000China Jiangsu Province Engineering Research Center of Intelligent Manufacturing Technology for the New Energy Vehicle Power Battery Changzhou Key Laboratory of Intelligent Manufacturing and Advanced Technology for Power BatterySchool of Materials Science and EngineeringChangzhou UniversityChangzhou 213164China

The extremely low electrical conductivity and ion-diffusion coefficient of li_(2)FeSiO_(4)limits its application as a cathode material in lithium-ion batteries.Therefore,in situ boron-doped li_(2)FeSi_(1)-xB_(x)O_(4-δ)/C(x=0,0.01,0.03,0.05 and 0.07)at the Si site was prepared via the solid-state reaction method using pitch as the c arbon source.B doping in the lattice structure and a c arbon coating on the surface of the composites could effectively enhance the li^(+)/electron conductivity.Moreover,the reduced particle size of the active material with the relatively high specific area via borondoped modification could improve the wettability between the electrolyte and cathode.With the synergistic effect of appropriate boron doping and carbon coating,it exhibits a good rate performance,specific capacity,and cycling performance.As a result,the as-prepared li_(2)FeSi_(0.95)B_(0.05)O_(4-δ)/C cathode showed a high discharge capacity of 160.7mAh·g^(-1)at 0.2C,and the capacity retention rate was 96%after 100 cycles at 1.0C.This work presents an effective path for designing advanced cathode materials for lithium-ion batteries.

关键词： li_(2)FeSiO_(4) Carbon coating Boron doping Synergistic effect lithium-ion battery

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Ultrathin Acoustic Parity-Time Symmetric Metasurface Cloak

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Research 2019年第1期2019卷 671-677页

作者： hao-xiang li Mar-a Rosendo-López Yi-fan Zhu Xu-dong Fan Daniel Torrent Bin liang Jian-chun Cheng Johan Christensen Key Laboratory of Modern Acoustics MOEInstitute of AcousticsDepartment of PhysicsCollaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210093China Department of Physics Universidad Carlos III de Madrid28916 LeganesMadridSpain GROC UJIInstitut de Noves Tecnologies de la Imatge(INIT)Universitat Jaume I12080 Castell`eSpain

Invisibility or unhearability cloaks have been made possible by using metamaterials enabling light or sound to fow around obstacle without the trace of refections or shadows.Metamaterials are known for being fexible building units that can mimic a host of unusual and extreme material responses,which are essential when engineering artifcial material properties to realize a coordinate transforming cloak.Bending and stretching the coordinate grid in space require stringent material parameters;therefore,small inaccuracies and inevitable material losses become sources for unwanted scattering that are decremental to the desired efect.Tese obstacles further limit the possibility of achieving a robust concealment of sizeable objects from either radar or sonar detection.By using an elaborate arrangement of gain and lossy acoustic media respecting parity-time symmetry,we built a one-way unhearability cloak able to hide objects seven times larger than the acoustic wavelength.Generally speaking,our approach has no limits in terms of working frequency,shape,or size,specifcally though we demonstrate how,in principle,an object of the size of a human can be hidden from audible sound.

关键词： coordinate stretching arrangement

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Numerical Study on the Effect of Vortex Generators on the Aerodynamic Drag of a High-Speed Train

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Fluid Dynamics & Materials Processing 2024年第2期20卷 463-473页

作者： Tian li hao liang Zerui xiang Jiye Zhang State Key Laboratory of Rail Transit Vehicle System Southwest Jiaotong UniversityChengdu610031China School of Design Southwest Jiaotong UniversityChengdu610031China

A relatively high aerodynamic drag is an important factor that hinders the further acceleration of high-speed trains.Using the shear stress transport(SST)k-ωturbulence model,the effect of various vortex generator types on the aerodynamic characteristics of an ICE2(Inter-city Electricity)train has been investigated.The results indi-cate that the vortex generators with wider triangle,trapezoid,and micro-ramp arranged on the surface of the tail car can signiﬁcantly change the distribution of surface pressure and affect the vorticity intensity in the wake.This alteration effectively reduces the resistance of the tail car.Meanwhile,the micro-ramp vortex generator with its convergent structure at the rear exhibits enhancedﬂow-guiding capabilities,resulting in a 15.4%reduction in the drag of the tail car.

关键词： Vortex generator aerodynamic drag reduction numerical simulation

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Alternative relay regulates the adenosine triphosphatase activity of Locusta migratoria striated muscle myosin

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Insect Science 2024年第2期31卷 435-447页

作者： Jie hao Chang liu Ning Zhang Jing li Tong Ni Mingbo Qu xiang-dong li State Key Laboratory oflntegrated Management of lnsect Pests and Rodents Insttute of ZoologyChinese Academy of SciencesBejingChina University of Chinese Academy of Sciences BejingChina School of Bioengeering Dalian University of TechnologyDalianChina

Locust(Locusta migratoria)has a single striated muscle myosin heavy chain(Mhc)gene,which contains 5 clusters of alternative exclusive exons and 1 differently included penultimate exon.The alternative exons of Mhc gene encode 4 distinct regions in the myosin motor domain,that is,the N-terminal SH3-like domain,one lip of the nucleotide-binding pocket,the relay,and the converter.Here,we investigated the role of the alternative regions on the motor function of locust muscle myosin.Using Sf9-baculovirus protein expression system,we expressed and purified 5 isoforms of the locust muscle myosin heavy meromyosin(HMM),including the major isoform in the thorax dorsal longitudinal flight muscle(FL1)and 4 isoforms expressed in the abdominal intersegmental muscle(AB1 to AB4).Among these 5 HMMs,FL1-HMM displayed the highest level of actin-activated adenosine triphosphatase(ATPase)activity(hereafter referred as ATPase activity).To identify the alternative region(s)responsible for the elevated ATPase activity of FL1-HMM,we produced a number of chimeras of FL1-HMM and AB4-HMM.Substitution with the relay of AB4-HMM(encoded by exon-14c)substantially decreased the ATPase activity of FL1-HMM,and conversely,the relay of FL1-HMM(encoded by exon-14a)enhanced the ATPase activity of AB4-HMM.Mutagenesis showed that the exon-14a-encoded residues Gly474 and Asn509 are responsible for the elevated ATPase activity of FL1-HMM.Those results indicate that the alternative relay encoded by exon-14a/c play a key role in regulating the ATPase activity of FL1-HMM and AB4-HMM.

关键词： alternative splicing ATPase Locusta migratoria molecular motor muscle myosin

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Double-ring high-frequency common-mode switching oscillation current sensor for inverter-fed machine winding insulation monitoring

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Global Energy Interconnection 2024年第1期7卷 106-116页

作者： lingqing Pan Xizhou Du Xing Lei Ting Ye Dawei xiang hao li College of Electrical Power Engineering Shanghai University of Electric PowerShanghai 200090P.R.China State Grid Shanghai Municipal Electric Power Company Shanghai 200122P.R.China College of Electronics and Information Engineering Tongji UniversityShanghai 201804P.R.China

Insulation failure significantly contributes to the unpredictable shutdown of power equipment.Compared to the partial discharge and high-frequency(HF)injection methods,the HF common-mode(CM)leakage current method offers a non-intrusive and highly sensitive alternative.However,the detection of HF CM currents is susceptible to interference from differential-mode(DM)currents,which exhibit high-amplitude and multifrequency components during normal operation.To address this challenge,this paper proposes a double-ring current sensor based on the principle of magnetic shielding for inverter-fed machine winding insulation monitoring.The inner ring harnesses the magnetic aggregation effect to isolate the DM current magnetic field,whereas the outer ring serves as the magnetic core of the Rogowski current sensor,enabling HF CM current monitoring.First,the magnetic field distributions of the CM and DM currents were analyzed.Then,a correlation between the sensor parameters and signal-to-noise ratio of the target HF CM current was established.Finally,an experimental study was conducted on a 3-kW PMSM for verification.The results indicate that the proposed double-ring HF CM sensor can effectively mitigate DM current interference.Compared to a single-ring sensor,a reduction of approximately 40%in the DM component was achieved,which significantly enhanced the precision of online insulation monitoring.

关键词： Magnetic shielding Double-ring Common-mode current Maxwell simulation

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High-sensitive state perception method for inverter-fed machine turn insulation based on FrFT-Mel

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Global Energy Interconnection 2024年第2期7卷 155-165页

作者： Ruitian Fan Xing Lei Tao Jia Menglong Qin hao li Dawei xiang College of Electrical Power Engineering Shanghai University of Electric PowerShanghai 200090P.R.China State Grid Shanghai Municipal Electric Power Company Shanghai 200437P.R.China State Grid Technology College Shandong 250002P.R.China College of Electronics and Information Engineering Tongji UniversityShanghai 201804P.R.China

Amidst the swift advancement of new power systems and electric vehicles,inverter-fed machines have progressively materialized as a pivotal apparatus for efficient energy conversion.Stator winding turn insulation failure is the root cause of inverter-fed machine breakdown.The online monitoring of turn insulation health can detect potential safety risks promptly,but faces the challenge of weak characteristics of turn insulation degradation.This study proposes an innovative method to evaluate the turn insulation state of inverter-fed machines by utilizing the fractional Fourier transform with a Mel filter(FrFT-Mel).First,the sensitivity of the high-frequency(HF)switching oscillation current to variations in turn insulation was analyzed within the fractional domain.Subsequently,an improved Mel filter is introduced,and its structure and parameters are specifically designed based on the features intrinsic to the common-mode impedance resonance point of the electrical machine.Finally,an evaluation index was proposed for the turn insulation state of inverter-fed machines.Experimental results on a 3kW permanent magnet synchronous machine(PMSM)demonstrate that the proposed FrFT-Mel method significantly enhances the sensitivity of turn insulation state perception by approximately five times,compared to the traditional Fourier transform method.

关键词： State perception Turn insulation Switching oscillation Fractional Fourier transform Mel filter

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Characterization of heat shock protein 90, 70 and their transcriptional expression patterns on high temperature in adult of Graphofita molesta （Busck）

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Insect Science 2014年第4期21卷 439-448页

作者： hao Chen xiang-li Xu Yi-Ping li Jun-xiang Wu Key Laboratory of Plant Protection Resources and Pest Management (Northwest A&F University) Ministry of Education Key Laboratoryof Appfied Entomology Northwest A&F University Yangling Shaanxi China

Grapholita molesta （Busck） is a worldwide insect pest damaging stone and pome fruits. High temperature can significantly affect insect survival, development and fecundity. Heat shock protein （Hsp） genes were speculated to possess a pivotal function in response to high temperature stress. In this study, two full-length Hsp genes, Gmhsp90 and GmhspTO, were cloned from G. molesta using rapid amplification of complementary DNA ends （RACE）. The open reading frames of Gmhsp90 and Gmhsp70 obtained were 2 148 bp and 1 998 bp in length, respectively. Their deduced amino acids showed high homology to Hsp genes of other species. Subsequently, the transcriptional expression of Gmhsp90 and Gmhsp70 in G. molesta adults exposed at various temperatures （26, 29, 32, 35, 38, 41 and 44℃） for 1 h and at 41℃ for various time duration （0, 15, 30, 45, 60, 75, 90 and 105 min） were investigated via real time quantitative polymerase chain reaction （qPCR）. The relative expression levels of Gmhsp90 and Gmhsp70 in G. molesta adults were both up-regulated with the rise of temperature and time duration. In addition, the Gmhsp70 usually showed a higher transcription accumulation than Gmhsp90. Interestingly, Gmhsp90 and Gmhsp 70 in female adults could be induced much earlier than that in males, and the effective induction temperature in females was also lower than that in males. The distinct expression profiles of Gmhsp90 and Gmhsp 70 indicated that Gmhsp90 and Gmhsp 70 may play important roles in G. molesta adults responding to a thermal threat, and there is difference on induction between sexes.

关键词： Grapholita molesta heat shock protein high temperature sex difference

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Mitigating set-stuck failure in 3D phase change memory: substituting square pulses with surge pulses

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Science China(Information Sciences) 2024年第5期67卷 295-301页

作者： Ninghua li Wang CAI Jun xiang hao TONG Weiming CHENG xiangshui MIAO School of Integrated Circuits Huazhong University of Science and Technology Hubei Yangtze Memory Laboratories Hubei Institute of Measurement and Testing Technology

In the devices that integrate phase change memory(PCM) and ovonic threshold switching(OTS),the OTS threshold voltage often surpasses the RESET operation voltage of PCM. The conventional application of square pulses hinders the successful completion of the SET operation in these integrated devices. To address this challenge, a novel pulse called the surge pulse is introduced, which comprises a high amplitude pulse for OTS activation and a low amplitude pulse for PCM operation. By employing COMSOL simulation,the operational effectiveness of both square pulses and surge pulses is validated. Test results reveal that using a square pulse to operate the integrated device accelerates the occurrence of SET-stuck failure(SSF).In contrast, the surge pulse enables the integrated device to operate for at least 1000 cycles while preserving the essential cyclic characteristics. Additionally, an investigation into the overshoot component of the surge pulse is conducted, revealing that an increase in overshoot amplitude and pulse width also accelerates the emergence of SSF. By applying the theory of ion migration induced by the electric field, the root cause of SSF in integrated devices is explained, and the accuracy of the theory is validated through the application of a reverse pulse. In summary, this study elucidates the rationality of replacing the square pulse with a surge pulse, presenting a superior approach for operating PCM and OTS integrated devices.

关键词： surge pulse phase change memory (PCM) integration SET-stuck failure (SSF) square pulse

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Remote copper-catalyzed enantioselective substitution of yne-thiophene carbonates

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Science China Chemistry 2024年第4期67卷 1175-1180页

作者： hao-Dong Qian xiang li Tingrui Yin Wei-Feng Qian Chunhui Zhao Cuiju Zhu hao Xu CCNU-uOttawa Joint Research Centre Key Laboratory of Pesticides&Chemical Biology of Ministry of EducationInternational Joint Research Center for Intelligent Biosensing Technology and HealthCollege of ChemistryCentral China Normal UniversityWuhan 430079China

Here,we describe a strategy for the copper-catalyzed asymmetric heteroarylation of yne-thiophene carbonates with indoles via remote substitution.The key to the success of this strategy lies in the design of the alkynyl group at the ortho-position of the heterocycle thiophene,enabling the formation of a triarylmethane moiety via very remote substitution.Thus,the concept of remote copper-catalyzed asymmetric transformation extends not only to yne-allylic esters but also to yne-aryl esters.The reaction readily provides a diverse array of chiral triarylmethanes with high efficiency,enantioselectivity,and excellent functional group compatibility.Moreover,facile follow-up transformations underscore their potential utility in the synthesis of various enantioenriched building blocks.Preliminary mechanistic studies support the plausibility of the remote substitution pathway.

关键词： remote substitution copper catalyst asymmetric catalysis triaryl methanes

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New insights into the pre-lithiation kinetics of single-crystalline Ni-rich cathodes for long-life li-ion batteries

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Green Energy & Environment 2024年第3期9卷 556-564页

作者： Qiang Han Lele Cai Zhaofeng Yang Yanjie Hu hao Jiang Chunzhong li Shanghai Engineering Research Center of Hierarchical Nanomaterials School of Chemical EngineeringEast China University of Science and TechnologyShanghai200237China Key Laboratory for Ultrafine Materials of Ministry of Education School of Materials Science and EngineeringEast China University of Science and TechnologyShanghai200237China

Developing single-crystalline Ni-rich cathodes is an effective strategy to improve the safety and cycle life of li-ion batteries(liBs).However,the easy-to-loss of li and O in high-temperature lithiation results in unsatisfactory ordered layered structure and stoichiometry.Herein,we demonstrate the synthesis of highly-ordered and fully-stoichiometric single-crystalline liNi_(0.83)Co_(0.12)Mn_(0.05)O_(2)(SC-NCM83)cathodes by the regulation of pre-lithiation kinetics.The well-balanced pre-lithiation kinetics have been proved to greatly improve the proportion of layered phase in the intermediate by inhibiting the formation of metastable spinel phase,which promoted the rapid transformation of the intermediate into highly-ordered layered SC-NCM83 in the subsequent lithiation process.After coating a layer of li_(2)O–B_(2)O_(3),the resultant cathodes deliver superior cycling stability with 90.9%capacity retention at 1C after 300 cycles in pouch-type full batteries.The enhancement mechanism has also been clarified.These findings exhibit fundamental insights into the pre-lithiation kinetics process for guiding the synthesis of high-quality singlecrystalline Ni-rich cathodes.

关键词： Single-crystalline cathode Ni-rich oxides Pre-lithiation li-ion batteries Surface modification

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