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The Predictability Limit of Oceanic Mesoscale Eddy Tracks in the South China Sea

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Advances in Atmospheric Sciences 2024年第9期41卷 1661-1679页

作者： Hailong LIU Pingxiang CHU Yao MENG Mengrong DING pengfei LIN Ruiqiang DING pengfei wang Weipeng ZHENG LASG Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Laoshan Laboratory Qingdao 266237China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China Marine Science and Technology College Zhejiang Ocean UniversityZhoushan 316022China State Key Laboratory of Earth Surface Processes and Resource Ecology Beijing Normal UniversityBeijing 100872China Center for Monsoon System Research(CMSR) Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100190China

Employing the nonlinear local Lyapunov exponent (NLLE) technique, this study assesses the quantitative predictability limit of oceanic mesoscale eddy (OME) tracks utilizing three eddy datasets for both annual and seasonal means. Our findings reveal a discernible predictability limit of approximately 39 days for cyclonic eddies (CEs) and 44 days for anticyclonic eddies (AEs) within the South China Sea (SCS). The predictability limit is related to the OME properties and seasons. The long-lived, large-amplitude, and large-radius OMEs tend to have a higher predictability limit. The predictability limit of AE (CE) tracks is highest in autumn (winter) with 52 (53) days and lowest in spring (summer) with 40 (30) days. The spatial distribution of the predictability limit of OME tracks also has seasonal variations, further finding that the area of higher predictability limits often overlaps with periodic OMEs. Additionally, the predictability limit of periodic OME tracks is about 49 days for both CEs and AEs, which is 5-10 days higher than the mean values. Usually, in the SCS, OMEs characterized by high predictability limit values exhibit more extended and smoother trajectories and often move along the northern slope of the SCS.

关键词： predictability mesoscale eddy nonlinear local Lyapunov exponent South China Sea seasonal variability

Numerical simulation of dust distribution at a fully mechanized face under the isolation effect of an air curtain

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Mining Science and Technology 2011年第1期21卷 65-69页

作者： wang pengfei Feng Tao Liu Ronghua School of Resources and Safety Engineering Central South University Changsha 410083 China School of Energy ＆Safety Engineering Hunan University of Science and Technology Xiangtan 411201 China

At a fully mechanized working face of a coal mine as prototype,we investigated,by simulation,the flow field and dust distribution during the process of its isolation by a curtain of air,using the CFD software, *** results show that the air curtain installed on the shearer can effectively prevent the dust （especially the respirable dust）from diffusing into the work area of the operator,reducing the dust concentration on the side of the operator and greatly improving his working *** field application of the air curtain shows that the dust-isolation effect of an air curtain is quite *** isolation efficiency for respiratory dust is over 70%and,as well,it has good dust-isolation effect for nonrespiratory *** air curtain is a useful way to resolve the problem of dust-isolation at a fully mechanized working *** has a practical background elsewhere with more extensive applications.

关键词： Fully mechanized face Air curtain Dust distribution Numerical simulation Dust-isolation efficiency

Effect of graphitic carbon nitride powders on adsorption removal of antibiotic resistance genes from water

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Chinese Chemical Letters 2020年第10期31卷 2843-2848页

作者： Haiyin Zhan Yutong wang Xueyue Mi Zhiruo Zhou pengfei wang Qixing Zhou College of Environmental Science and Engineering Nankai UniversityTianjin 300071China School of Energy and Environmental Engineering Hebei University of TechnologyTianjin 300401China

There is a growing need to eliminate antibiotic resistance genes(ARGs)in the environment and mitigate widespread antibiotic *** carbon nitride(g-C_(3)N_(4))was successfully synthesized via facile thermal polymerization approach and its pote ntial for adsorption treatment of ARGs in water was *** adsorption experimental results revealed that g-C_(3)N_(4) powders had robust adsorption activity for the gene ampC and *** kinetics and isotherms were syste matically investigated to explain the adsorption *** apparent adsorption equilibrium could be reached within180 *** adsorption process effectively re moved ARGs(ampC and ermB)from water with 3.2 log and4.2 log reductions,*** addition,experimental data were analyzed by several models and simulated well with Langmuir isotherm and pseudo-second-order *** indicated that adsorption process might be dominated by the chemical rate-limiting ***,the effects of temperature and pH on the re moval of ARGs were conducted and the isoelectric point(IEP)was ***,we have demonstrated that the g-C_(3)N_(4) is a novel adsorbent and can be used as column packing to remove ARGs by filtration.

关键词： Antibiotic resistance genes Adsorption Removal Drinking water g-C_(3)N_(4)

Effect of Benzene Rings＇ Incorporation on Photovoltaic Performance of Indacenodithiophene-cored Molecular Acceptors

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Chinese Journal of Chemistry 2018年第4期36卷 306-310页

作者： Haijun Fan Hao Wu pengfei wang Xiaozhang Zhu Beijing National Laboratory for Molecular Sciences CAS Key Laboratory of Organic Solids Institute of Chemistry Chinese Academy of Sciences Beijing 100190 China University of Chinese Academy of Sciences Beijing 100049 China

Two simple molecular acceptors, NIDBT and NIDT, bearing the same end groups of 2-（3-oxo-2,3-dihydro-1H-inden-1-ylidene）malononitrile （INCN） yet with different core units, indenofluorenodithiophene （IDBT） and indaceno[2,1-b：6,5-b＇]dithiophene （IDT）, respectively, were adopted to fabri- cate polymer solar cells by blending with a narrow bandgap polymer donor, PBDBTBTT-Hex （P3）. The incorporation of benzene rings into the molecular skeletons generates a negative effect on the photovoltaic performance of resultant molecular acceptor, rendering an inferior power conversion efficiency of 2.45%, compared to 4.05% for the NlDT-based bulk-heterojunction solar cells. Detailed comparison on photovoltaic parameters indicates that the fusion by incorporating two separated benzene rings into the IDT core renders molecular acceptor of weakened intermolecular interaction with the pol- ymer donor, which results in over-aggregated phase separation, unbalanced charge transport, and serious recombination within the photovoltaic devices. The work contributes to a deep understanding of the effect of skeleton-fusion strategy for designing high-performance molecular acceptors.

关键词： polymer solar cells molecular acceptor indacenodithiophene indenofiuorenodithiophene

Anti-swarm UAV radar system based on detection data fusion

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Journal of Systems Engineering and Electronics 2024年第5期35卷 1167-1176页

作者： wang pengfei HU Jinfeng HU Wen wang Weiguang DONG Hao School of Information and Communication Engineering University of Electronic Science and Technology of ChinaChengdu 611731China China Airborne Missile Academy Luoyang 471009China Yangtze Delta Region Institute(Quzhou) University of Electronic Science and Technology of ChinaQuzhou 324003China College of Electronic and Information Engineering Nanjing University of Aeronautics and AstronauticsNanjing 211106China

There is a growing body of research on the swarm unmanned aerial vehicle(UAV)in recent years,which has the characteristics of small,low speed,and low height as radar *** confront the swarm UAV,the design of anti-UAV radar system based on multiple input multiple output(MIMO)is put forward,which can elevate the performance of resolution,angle accuracy,high data rate,and tracking flexibility for swarm UAV *** resolution and detection are the core problem in detecting the swarm *** distinct advantage of MIMO system in angular accuracy measurement is demonstrated by comparing MIMO radar with phased array *** MIMO radar has better performance in resolution,swarm UAV detection still has difficulty in target *** paper proposes a multi-mode data fusion algorithm based on deep neural networks to improve the detection ***,signal processing and data processing based on the detection fusion algorithm above are designed,forming a high resolution detection *** simulations are designed to illustrate the feasibility of the designed system and the proposed algorithm.

关键词： swarm radar high resolution deep neural network fusion algorithm

Experimental study on atomization characteristics and dust-reduction performance of four common types of pressure nozzles in underground coal mines

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International Journal of Coal Science & Technology 2020年第3期7卷 581-596页

作者： Han Han pengfei wang Ronghua Liu Chang Tian Work Safety Key Lab on Prevention and Control of Gas and Roof Disasters for Southern Coal Mines Hunan University of Science and TechnologyXiangtan411201China School of Resource Environment and Safety Engineering Hunan University of Science and TechnologyXiangtan411201China Department of Civil and Architectural Engineering and Mechanic University of ArizonaTucsonAZ85721USA

Pressure nozzle is commonly used in the dust-reduction techniques by spraying of underground coal *** on the internal structure,the pressure nozzle can be divided into the following types:spiral channel nozzle,tangential flow-guided nozzle and X-swirl *** order to provide better guidance on the selection of nozzles for the coal mine dust-reduction systems by spraying,we designed comparing experiments to study the atomization characteristics and dust-reduction performance of four commonly used nozzles in the coal mine underground with different internal *** the experimental results on the atomization characteristics,both the tangential flow-guided nozzle and the X-swirl nozzle have high flow *** atomization angle is the largest in the spiral non-porous nozzle,and smallest in both the X-swirl nozzle and the spiral porous *** spraying range and the droplet velocity are inversely proportional to the atomization *** the water pressure is low,the atomization performance of the spiral non-porous nozzle is the best among the four types of *** atomization performance of the X-swirl nozzle is superior to other types when the water pressure is *** the high water pressure,the particle size of the atomized droplets is smallest in the X-swirl *** the experiments on the dust-reduction performance of the four types of nozzles and the comprehensive analysis,the X-swirl nozzle is recommended for the coal mine application site with low water pressure in the dust-reduction system,while at the sites with high water pressure,the spiral non-porous nozzle is recommended,which has the lowest water consumption and obvious economic advantages.

关键词： Pressure nozzle Atomization characteristics Dust-reduction performance Droplets Dust

Novel thioxanthone host material with thermally activated delayed fluorescence for reduced efficiency roll-off of phosphorescent OLEDs

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Chinese Chemical Letters 2018年第3期29卷 471-474页

作者： Hui wang Xiaopeng Lv Lingqiang Meng Xiaofang Wei Ying wang pengfei wang Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education College of Chemistry & Materials Science Northwest University Xi'an 710127 China Key Laboratory of Photochemical Conversion and Optoelectrontc Materials Technical Institute of Physics and Chemistry Chinese Academy of Sciences Beijing 100190 China Institute of Functional Nano and Soft Materials Soochow University Suzhou 215123 China

2,7-Di（9,9-dimethyl-9H-fluoren-l-yl）-9H-thioxanthen-9-one （DMBFTX） with thermally activated delayed fluorescence （TADF） was well designed and synthesized. The phosphorescent organic lightemitting device （PHOLED） based on this novel TADF host material displays a stable red phosphorescence region, a peak external quantum efficiency （EQE） value of 12.9% and a low EQE roll-off of 38.8%at a luminance of 10000 cd/m2, which is benefited from the reverse intersystem crossing （RISC） of TADF host and less populated triplet exitons. Notably, the red device based on the TADF host DMBFrX exhibits superior electroluminescence performance and reduced efficiency roll-offcompared with the one hosted by commercially available host 1,3-bis（9-carbazolyl）benzene （mCP）, illustrating the high potential of employing the TADF host material with small energy gap to reduce efficiency roll-off in PHOLED.

关键词： Low efficiency roll-off Thermally activated delayed fluorescence Small energy gap Reverse intersystem crossing Phosphorescent OLEDs

Control of a Quadruped Robot with Bionic Springy Legs in Trotting Gait

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Journal of Bionic Engineering 2014年第2期11卷 188-198页

作者： Mantian Li Zhenyu Jiang pengfei wang Lining Sun Shuzhi Sam Ge State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin 150001 P. R. China Institute of Intelligent Systems and Information Technology University of Electronic Seience and Technology of China Chengdu 610000 P.R. China Department of Electrical and Computer Engineering the National University of Singapore Singapore 117576 Singapore

Legged robots have better performance on discontinuous terrain than that of wheeled robots. However, the dynamic trotting and balance control of a quadruped robot is still a challenging problem, especially when the robot has multi-joint legs. This paper presents a three-dimensional model of a quadruped robot which has 6 Degrees of Freedom （DOF） on torso and 5 DOF on each leg. On the basis of the Spring-Loaded Inverted Pendulum （SLIP） model, body control algorithm is discussed in the first place to figure out how legs work in 3D trotting. Then, motivated by the principle of joint function separation and introducing certain biological characteristics, two joint coordination approaches are developed to produce the trot and provide balance. The robot reaches the highest speed of 2.0 m.s-1, and keeps balance under 250 Kg.m.s-1 lateral disturbance in the simulations. The effectiveness of these approaches is also verified on a prototype robot which runs to 0.83 m.s-1 on the treadmill, The simulations and experiments show that legged robots have good biological properties, such as the ground reaction force, and spring-like leg behavior.

关键词： legged robots locomotion control quadruped robot trotting gait

The effects of deep-level defects on the electrical properties of Cd0.9Zn0.1Te crystals

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Journal of Semiconductors 2017年第6期38卷 8-13页

作者： pengfei wang Ruihua Nan Zengyun Jian School of Materials and Chemical Engineering Xi'an Technological University Xi'an 710021 China

The deep-level defects of Cd Zn Te（CZT）crystals grown by the modified vertical Bridgman（MVB）method act as trapping centers or recombination centers in the band gap,which have significant effects on its electrical *** resistivity and electron mobility–lifetime product of high resistivity Cd（0.9）Zn（0.1）Te wafer marked CZT1 and low resistivity Cd（0.9）Zn（0.1）Te wafer marked CZT2 were tested *** deep-level defects were identified by thermally stimulated current（TSC）spectroscopy and thermoelectric effect spectroscopy（TEES）*** the trap-related parameters were characterized by the simultaneous multiple peak analysis（SIMPA）*** deep donor level（EDD/dominating dark current was calculated by the relationship between dark current and *** Fermi-level was characterized by current–voltage measurements of temperature *** width of the band gap was characterized by ultraviolet-visible-infrared transmittance *** results show the traps concentration and capture cross section of CZT1 are lower than CZT2,so its electron mobility–lifetime product is greater than *** Fermi-level of CZT1 is closer to the middle gap than *** degree of Fermi-level pinned by EDDof CZT1 is larger than *** can be concluded that the resistivity of CZT crystals increases as the degree of Fermi-level pinned near the middle gap by the deep donor level enlarges.

关键词： Cdo.9Zn0.1Te deep-level defects thermally stimulated current spectroscopy Fermi-level electrical properties