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Synthesis and electrochemical performance of micro-nano structured li Fe1-xMnxPO4/C(0≤x≤0.05)cathode for lithium-ion batteries

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Journal of Energy Chemistry 2018年第3期27卷 923-929页

作者： Chunyang li guojun li Xiaomei Guan liaoning Key Lab for New Energy Battery Dalian Jiaotong UniversityDalian 116028LiaoningChina School of Materials Science and Engineering Dalian Jiaotong UniversityDalian 116028LiaoningChina

Micro-nano structured li Fe（1-x）MnxPO4/C（0≤x≤0.05）cathodes were prepared by spray drying,followed by calcination at 700°*** spherical li Fe（1-x）MnxPO4/C（0≤x≤0.05）particles with the size of 0.5 to5.0μm are composed of lots of nanoparticles of 20 to 30 nm,and have the well-developed interconnected pore *** contrast,when Mn doping content is 3 mol%（x=0.03）,the li Fe（0.97）Mn（0.03）PO4/C demonstrates maximum specific surface area of 31.30 m^2/g,more uniform pore size and relatively better electrochemical *** initial discharge capacities are 161.59,157.04 and 153.13 m Ah/g at a discharge rate of 0.2,0.5 and 1 C,***,the discharge capacity retentions are～100%after 120 *** improved electrochemical performance should be attributed to higher specific surface,smaller polarization voltage,and a high li~＋diffusion rate due to the micro-nano porous structure and lattice expansion produced by Mn doping.

关键词： li Fe1-xMnxPO4/C Spray drying Electrochemical property Micro-nano structure

New Construction of Quadriphase Golay Complementary Pairs

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Chinese Journal of Electronics 2023年第5期32卷 1059-1065页

作者： li guojun ZENG Fanxin YE Changrong Lab of Beyond LOS Reliable Information Transmission Chongqing University of Posts and Telecommunications

Based on an arbitrarily-chosen binary Golay complementary pair(BGCP)(c,d) of even length N, first of all, construct quadriphase sequences a and b of length N by weighting addition and difference of the aforementioned pair with different weights, ***, new quadriphase sequence u is given by interleaving three sequences d, a, and-c, and similarly, the sequence v is acquired from three sequences d, b, and ***, the resultant pair(u,v) is the quadriphase Golay complementary pair(QGCP) of length 3N. The QGCPs play a fairly important role in communications, radar, and so on.

关键词： Histograms Systematics Computer simulation Radar

Construction of 3D/2D indium vanadate /graphite carbon nitride with nitrogen defects Z-scheme heterojunction for improving photocatalytic carbon dioxide reduction

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Journal of Materials Science & Technology 2023年第23期154卷 129-139页

作者： Mingyi Yu Jianbo Wang guojun li Shule Zhang Qin Zhong School of Chemistry and Chemical Engineering Nanjing University of Science and TechnologyNanjing 210094China

Indium vanadate (InVO4 ) possesses excellent potential in photocatalytic carbon dioxide (CO_(2) ) reduction, but further modifications of reducing charge recombination and increasing active sites are still needed. Herein, InVO4 /g-C3 N4 (InVO-CN) heterojunction composite photocatalysts were prepared via in situ formation of InVO4 nanoparticles on the lamellar structure of graphite carbon nitride (g-C3 N4 ) containing nitrogen (N) defects. Among these composites, 30% InVO-CN showed the best photoreduction performance for CO_(2) at normal temperature and pressure without sacrificial agent (carbon monoxide, CO: 20.14 μmol g–1 h–1;methane, CH4 : 3.46 μmol g–1 h–1 ), which were 1.8 and 2.8 times higher than these of pure g-C3 N4 and InVO4 . The excellent performance could be attributed to the enhancement of CO_(2) adsorption, and most importantly, the enhanced charge carrier separation and reduction capacity induced by the formation of Z-scheme heterojunction between InVO4 and g-C3 N4 . In this work, intimate heterojunction interfaces between materials were formed by introducing g-C3 N4 with defects in InVO4 , which provides a promising modification scheme.

关键词： Z-scheme heterojunction CO_(2)photoreduction g-C3N4,InVO4

Soft Template-Induced Porous Polyvinylidene Fluoride Membrane for Vanadium Flow Batteries

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Transactions of Tianjin University 2023年第4期29卷 284-292页

作者： Dingqin Shi Chunyang li Zhizhang Yuan guojun li Metal-Air New Energy Batteries Key Laboratory of liaoning Province Dalian Jiaotong UniversityDalian 116028China Division of Energy Storage Dalian National Laboratory for Clean Energy(DNL)Dalian Institute of Chemical PhysicsChinese Academy of Sciences116023 DalianChina

Vanadium flow batteries(VFBs)are considered ideal for grid-sc ale,long-duration energy storage applications owing to their decoupled output power and storage capacity,high safety,efficiency,and long cycle ***,the widespread adoption of VFB s is hindered by the use of expensive Nafion ***,we report a soft template-induced method to develop a porous polyvinylidene fluoride(PVDF)membrane for VFB *** incorporating water-soluble and flexible polyethylene glycol(PEG 400)as a soft template,we induced the aggregation of hydrophilic sulfonated poly(ether ether ketone),resulting in phase separation from the hydrophobic PVDF polymer during membrane *** process led to the creation of a porous PVDF membrane with controllable morphologies determined by the polyethylene glycol content in the cast *** optimized porous PVDF membrane enabled a stable VFB performance for 200 cycles at a current density of 80 mA/cm^(2),and the VFB exhibited a Coulombic efficiency of 95.2%and a voltage efficiency of 87.8%.These findings provide valuable insights for the development of highly stable membranes for VFB applications.

关键词： Energy storage Vanadium flow battery Porous polyvinylidene fluoride membrane Soft template-induced phase separation

Microstructure and Mechanical Properties of Multilayer Ti(C,N) Films by Closed-field Unbalanced Magnetron Sputtering Ion Plating

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Journal of Materials Science & Technology 2010年第2期26卷 119-124页

作者： guojun Zhang Bin li Bailing Jiang Dichun Chen Fuxue Yan School of Materials Science and Engineering Xi~an University of Technology Xi'an 710048 China

Ti（C, N） multilayer films have been prepared by closed-field unbalanced magnetron sputtering technology and using graphite target as the C supplier. Microstructural observation results showed that the Ti（C, N） films exhibited multilayer structure with most of fine nano-columnar Ti（C, N） grains existing in the films. The current of graphite target had an effect remarkably on the multilayer structure of films： the periodical thickness gradually increased as the current went up, but the grain size of films gradually decreased and even amorphous phase appeared as the current further increased. The microstructure of Ti（C, N） films changed from columnar crystallite to nanocomposite in high current of graphite target where the fine Ti（C, N） grains were distributed uniformly in the amorphous Ti（C, N） matrix, and the volume fraction of the amorphous phase increased with increasing current. Measurement results showed that the Ti（C, N） multilayer films have high rnicrohardness and low friction coefficient, and especially the film deposited in the current of 0.9 A exhibits superior properties with optimizing hardness and friction coefficient. Based on the relationship of the microstructure and the properties of films, the multilayer structure and fine grain size of Ti（C, N） films are responsible for their well mechanical and friction properties. And choosing the graphite target as the C supplier is more propitious to decrease the friction coefficients of films.

关键词： Ti(C, N) Multilayer film Graphite target

Active High-Locality Landslides in Mao County: Early Identification and Deformational Rules

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Journal of Earth Science 2023年第5期34卷 1596-1615页

作者： Xianmin Wang Jing Yin Menghan Luo Haifeng Ren Jing li lizhe Wang Dongdong li guojun li Hubei Subsurface Multi-Scale Imaging Key Laboratory School of Geophysics and GeomaticsChina University of GeosciencesWuhan 430074China Changsha Planning Information Service Center Changsha Municipal Bureau of Natual Resources and PlanningChangsha 410221China National Engineering Research Center for Geoinformatics Aerospace Information Research InstituteChinese Academy of SciencesChinese Academy of SciencesBeijing 100101China College of Electronic Science and Engineering National University of Defense TechnologyChangsha 410073China Laboratory of Beyond LOS Reliable Information Transmission Chongqing University of Posts and TelecommunicationsChongqing 400065China

High-locality landslides are located on slopes at high elevations and are characterized by long sliding distances, large gravitational potential energy, high movement velocities, tremendous kinetic energy, and sudden onset. Thus, they often cause catastrophic damage to human lives and engineering facilities. It is of great significance to identify active high-locality landslides in their early deformational stages and to reveal their deformational rules for effective disaster mitigation. Due to alpinecanyon landforms, Mao County is a representative source of high-locality landslides. This work employs multisource data(geological, terrain, meteorological, ground sensor, and remote sensing data) and timeseries In SAR technology to recognize active high-locality landslides in Mao County and to reveal their laws of development. Some new viewpoints are suggested.(1) Nineteen active high-locality landslides are identified by the time-series In SAR technique, of which 7 are newly discovered in this work. All these high-locality landslides possessed good concealment during their early deformational stages. The newly discovered HL-16 landslide featured a large scale and a great slope height, posing a large threat to the surrounding buildings and residents.(2) The high-locality landslides in Mao County were mainly triggered by three factors: earthquakes, precipitation, and road construction.(3) Three typical high-locality landslides that were triggered by different factors are highlighted with their deformational rules under the functions of steep terrain, shattered rocks, fissure-water penetration, precipitation, and road construction. This work may provide clues to the prevention and control of high-locality landslides and can be applied to the determination of active high-locality landslides in other hard-hit areas.

关键词： high-locality landslide landslide identification deformational rule landslides engineering geology

A Characterization of Bicyclic Signed Graphs with Nullity n-7

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Journal of Mathematical Research with Applications 2015年第1期35卷 1-10页

作者： guojun li Aimei YU Department of Mathematics Beijing Jiaotong University

Let Γ be a signed graph and A(Γ) be the adjacency matrix of Γ. The nullity ofΓ is the multiplicity of eigenvalue zero in the spectrum of A(Γ). In this paper, the connected bicyclic signed graphs(including simple ... 详细信息

关键词： nullity signed graph bicyclic graph adjacency matrix

HAMILTONICITY IN 2-CONNECTED {K_(1,3) F}-FREE GRAPHS

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Systems Science and Mathematical Sciences 1996年第4期9卷 295-305页

作者： li guojun liU Zhenhong Mathematics Depertment of Yantai Teacher’s College Yantai 264000China Institute of Systems Science Academic SinicaBeijing 100080China

Let F be a graph consisting of a triangle with a pendant leaf dangling from each vertex.A graph is{K_(1,3),F}-free if it contains no induced subgraph isomorphic to K_(1,3)or *** give a stronger structural characterisation of{K_(1,3),F}-free graph with which we obtain a more general result than that in[1]as follows:Given any two venices in a 2-connected{K_(1,3),F}-free graph,if there exists a shortest path between them containing no 2-cutset of the graph,then the graph has a Hamilton path cormecting these two venices.

关键词： {K_(1,3) F}-free graph Hamilton connected vertex dominating cycle.

Based on self-made shale formation simulated artificial cores to evaluate water-based drilling fluids plugging effect technology

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Petroleum Research 2023年第1期8卷 11-17页

作者： Yang Bai Chunyan liu guojun li Ren Wang Dezhi liu Pingya Luo State Key Laboratory Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum UniversityChengdu610500China CNPC Engineering Technology R&D Company limited Beijing102206China

Plugging technology is one of the leading problems in shale gas drilling engineering,as it causes wellbore stability,shale formation collapse,and so *** order to solve these problems,in this paper,we committed to preparing artificial cores whose original permeability was 1.16×10^(−4)mD,which could be used to simulate the shale formation,and established a sealing evaluation method to assess the effect of plugging technology by measuring permeability reduction rate K'.Verified the good reproducibility of the artificial cores through a lot of high temperature and high pressure(HTHP)filtration *** Scanning electron microscopy(SEM)was used to prove that the permeability reduction rate is a scientific method to evaluate the sealing effect.

关键词： Plugging evaluation method Artificial cores Reproducibility Permeability reduction rate