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Deep feature extraction and motion representation for satellite video scene classification

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Science China(Information Sciences) 2020年第4期63卷 97-111页

作者： Yanfeng GU Huan LIU tengfei WANG Shengyang LI Guoming GAO School of Electronics and Information Engineering Harbin Institute of Technology Technology and Engineering Center for Space Utilization Chinese Academy of Sciences The Key Laboratory of Space Utilization Chinese Academy of Sciences

Satellite video scene classification(SVSC) is an advanced topic in the remote sensing field, which refers to determine the video scene categories from satellite videos. SVSC is an important and fundamental step for satellite video analysis and understanding, which provides priors for the presence of objects and dynamic events. In this paper, a two-stage framework is proposed to extract spatial features and motion features for SVSC. More specifically, the first stage is designed to extract spatial features for satellite *** frames are firstly selected based on the blur detection and spatial activity of satellite *** the fine-tuned visual geometry group network(VGG-Net) is transferred to extract spatial features based on spatial content. The second stage is designed to build motion representation for satellite *** motion representation of moving targets in satellite videos is first built by the second temporal principal component of principal component analysis(PCA). Second, features from the first fully connected layer of VGG-Net are used as high-level spatial representation for moving targets. Third, a small network of long and short term memory(LSTM) is further designed for encoding temporal information. Two-stage features respectively characterize spatial and temporal patterns of satellite scenes, which are finally fused for SVSC.A satellite video dataset is built for video scene classification, including 7209 video segments and covering 8 scene categories. These satellite videos are from Jilin-1 satellites and Urthecast. The experimental results show the efficiency of our proposed framework for SVSC.

关键词： satellite videos classification convolutional neural network CNN long and short term memory LSTM motion representation

Numerical study of transonic separation flow using an anisotropic turbulence model

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航空动力学报 2020年第1期35卷 114-125页

作者： YAN Wenhui PENG tengfei YONG Yan QIN Ruixin MA Ruige School of Mechanical and Materials Engineering North China University of TechnologyBeijing 100144China Department of Civil Environmental and Geomatics EngineeringFlorida Atlantic UniversityBoca RatonFlorida 33431U.S.A.

A transonic turbulent separation flow in a converging-diverging transonic diffuser was studied,when there existed a separation bubble on the top wall of the diffuser triggered by strong shock-wave-boundary-layer-interaction(SWBLI).To capture the essential behavior of this complex flow,the current study utilized an anisotropic turbulence model developed on the basis of a statistical partial average *** first order moment of turbulent fluctuations,retained by a novel average scheme,and the turbulent length scale,can be determined from the momentum equations and mechanical energy equation of the fluctuation flow,*** two physical quantities were readily used to construct the nonlinear anisotropic eddy viscosity tensor and to significantly improve the computational *** between the computational results and experimental data were carried out for velocity profiles,pressure distribution,skin friction coefficient,Reynolds stress as well as streamline vectors *** using any empirical coefficients and wall functions,the numerical results were in good agreement with the available experimental data,further confirming that the nonlinear anisotropic eddy viscosity tensor is the decisive factor for the success of the computational results.

关键词： transonic separation flow eddy viscosity tensor shock wave boundary layer interaction anisotropic turbulence model statistical partial average scheme

Effects of Thieno[3,2-b]thiophene Number on Narrow-Bandgap Fused-Ring Electron Acceptors

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Chinese Journal of Polymer Science 2022年第8期40卷 914-920,I0008页

作者： tengfei Li Guilong Cai Yuze Lin Xinhui Lu Xiaowei Zhan Key Laboratory of Polymer Chemistry and Physics of Ministry of Education School of Materials Science and EngineeringPeking UniversityBeijing100871China Beijing National Laboratory for Molecular Sciences CAS Key Laboratory of Organic SolidsInstitute of ChemistryChinese Academy of SciencesBeijing100190China Department of Physics The Chinese University of Hong KongHong Kong999077China

We synthesize and compare four near-infrared absorbing fused-ring electron acceptors named as nTTIC(n=2,3,4,and 5),based on different number of thieno[3,2-b]thiophene(TT)unit as the electron-donating *** increasing the TT unit,absorption spectrum of the TTIC series red shifts,and the highest occupied molecular orbital(HOMO)upshifts *** is worth noting that 4TTIC and 5TTIC exhibit absorption edges approaching 1100 nm,which is the photoresponse limit of solar cells based on crystal *** the TTIC series acceptors are blended with polymer donor PM6,the binary-blend organic solar cells based on 3TTIC show the best power conversion efficiency(PCE)of 13.1%.In contrast,2TTIC-based devices exhibit relatively lower PCE of 8.32%,mainly caused by the larger energy loss and blue-shifted *** to insufficient driving force of charge separation caused by very high HOMO,4TTIC and 5TTIC show poor PCEs lower than 3%.

关键词： Thieno[3,2-b]thiophene Near-infrared absorption Fused-ring electron acceptor Nonfullerene Organic solar cell

Determination of the available energy,standardized ileal digestibility of amino acids of fermented corn germ meal replacing soybean meal in growing pig diets

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Animal Nutrition 2022年第2期9卷 259-268页

作者： tengfei He Yuhui Zheng Xiangshu Piao Shenfei Long State Key Laboratory of Animal Nutrition College of Animal Science and TechnologyChina Agricultural UniversityBeijing 100193China

Three experiments were conducted to compare the digestible(DE),metabolizable energy(ME),and standardized ileal digestibility(SID)of amino acids(AA)in fermented corn germ meal(FCGM)and soybean meal(SBM),and evaluate the effects of FCGM replacing SBM in growing pig *** Exp.1,18 barrows with initial body weight(BW)of 60.2±3.40 kg were randomly allotted to 3 treatments with 6 replicates per *** control diet used corn as the only energy ingredient,and 2 test diets were made by replacing 25.8%of corn with FCGM or *** DE and ME of FCGM were less(P<0.01)than those of *** Exp.2,18 barrows(59.3±2.52 kg BW)with ileal T-cannulas were randomly allotted to 3 treatments with 6 replicates per *** SID of arginine,tryptophan and proline were greater(P<0.05)and the tyrosine was less(P=0.01)in SBM compared with *** Exp.3,144 growing pigs(56.1±5.22 kg BW)were randomly allotted to 4 treatments with 6 pens per treatment(3 barrows and 3 gilts per pen).Four diets(FCGM0,FCGM10,FCGM20 and FCGM30)were formulated using FCGM to replace 0%,10%,20%and 30%of SBM,*** ME and SID values of AA of SBM and FCGM were determined by Exp.1 and *** showed that increasing FCGM inclusion quadratically(P<0.05)increased the average daily gain(ADG),average daily feed intake,and the levels of serum immunoglobulin G(IgG)and urea nitrogen,and linearly(P<0.05)increased the serum IgM,the propanoic acid,butyric acid,total volatile fatty acid(VFA)and the Shannon index of microbiota in ***,the relative abundance of genus Streptococcus in FCGM0,Lactobacillus in FCGM10 and Lachnospiraceae in FCGM30 were increased(P<0.05)compared with other *** conclusion,we recommend replacing 11.80%of SBM with FCGM to obtain the optimal ADG of growing ***,as the ratio of FCGM replacing SBM increased in diet,the immunity,intestinal microbiota and total VFA composition of growing pigs were improved.

关键词： Available energy Amino acid digestibility Fermented corn germ meal Soybean meal Growing pig

Repurposing drugs for solid tumor treatment:focus on immune checkpoint inhibitors

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Cancer Biology & Medicine 2023年第11期20卷 856-868页

作者： Qingxu Liu Long Li Wan Qin tengfei Chao Department of Oncology Tongji Hospital of Tongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430030China

Cancer remains a significant global health challenge with limited treatment options beyond systemic therapies,such as chemotherapy,radiotherapy,and molecular targeted *** has emerged as a promising therapeutic modality but the efficacy has plateaued,which therefore provides limited benefits to patients with *** of more effective approaches to improve patient outcomes and extend survival are urgently *** repurposing has emerged as an attractive strategy for drug development and has recently garnered considerable *** review comprehensively analyses the efficacy of various repurposed drugs,such as transforming growth factor-beta(TGF-β)inhibitors,metformin,receptor activator of nuclear factor-κB ligand(RANKL)inhibitors,granulocyte macrophage colony-stimulating factor(GM-CSF),thymosinα1(Tα1),aspirin,and bisphosphonate,in tumorigenesis with a specific focus on their impact on tumor immunology and ***,we present a concise overview of the current preclinical and clinical studies investigating the potential therapeutic synergies achieved by combining these agents with immune checkpoint inhibitors.

关键词： Drug repurposing immune checkpoint inhibitor immunotherapy tumor microenvironment

Nighttime sap flow and its driving forces for Populus euphratica in a desert riparian forest, Northwest China

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Journal of Arid Land 2015年第5期7卷 665-674页

作者： SI Jianhua FENG Qi YU tengfei ZHAO Chunyan Alxa Desert Eco-hydrology Experimental Research Station Cold and Arid Regions Environmental and Engineering Research InstituteChinese Academy of Sciences Gansu Hydrology and Water Resources Engineering Center

Nighttime sap flow is a potentially important factor that affects whole-plant water balance and water-use efficiency （WUE）. Its functions include predawn disequilibrium between plant and soil water potentials as well as between the increments of oxygen supply and nutrient uptake. However, main factors that drive nighttime sap flow remain unclear, and researches related to the relationship between nighttime sap flow velocity and environmental factors are limited. Accordingly, we investigated the variations in the nighttime sap flow of Populus euphratica in a desert riparian forest of an extremely arid region, Northwest China. Results indicated that P. euphratica sap flow occurred throughout the night during the growing season because of the partial stomata opening. Nighttime sap flow for the P. euphratica forest accounted for 31%-47% of its daily sap flow during the growing season. The high value of nighttime sap flow could be the result of high stomatal conductance and could have significant implications for water budgets. Throughout the whole growing season, nighttime sap flow velocity of P. euphratica was positively correlated with the vapor pressure deficit （VPD）, air temperature and soil water content. We found that VPD and soil water content were the main driving factors for nighttime sap flow of P. euphratica.

关键词： nighttime sap flow stomatal conductance vapor pressure deficit driving factors desert riparian forest

On the room-temperature tensile deformation behavior of a cast dual-phase high-entropy alloy CrFeCoNiAl_(0.7)

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Journal of Materials Science & Technology 2021年第28期87卷 29-38页

作者： Qiang Wang Liangcai Zeng tengfei Gao Hui Du Xinwang Liu Key Laboratory of Metallurgical Equipment and Control Technology Ministry of EducationWuhan University of Science and TechnologyWuhan 430081China Hubei Key Laboratory of Mechanical Transmission and Manufacturing Engineering School of Machinery and AutomationWuhan University of Science and TechnologyWuhan 430081China State Key Laboratory of Materials Processing and Die&Mould Technology Huazhong University of Science and TechnologyWuhan 430074China

The microstructure and room-temperature tensile deformation behavior of the cast CrFeCoNiAl0.7 high-entropy alloy(HEA)were studied in *** cast HEA consisted of a dual-phase structure of 77.3 vol.%face-centered-cubic(FCC)phase plus 22.7 vol.%B2 phase,and exhibited excellent room-temperature tensile properties with a high yield strength of 876 MPa,ultimate tensile strength of 1198 MPa and a relatively large elongation to fracture of~9%.Dislocations gliding in the FCC phase governed the plastic deformation at the early stage of room-temperature tensile,and disordered dislocations were to form dislocation walls as the deformation *** further increase in strain to a high level,the stacking faults were generated through the dissociation of the geometrically necessary dislocations,serving as the potential heterogeneous nucleation sites for the deformation twins.

关键词： High-entropy alloy Microstructure Deformation mechanism Dislocation Stacking fault

Response of Populus euphratica *** flow to environmental variables for a desert riparian forest in the Heihe River Basin,Northwest China

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Journal of Arid Land 2016年第4期8卷 591-603页

作者： LI Wei SI Jianhua YU tengfei LI Xiaoyan College of Resources Science and Technology Beijing Normal University Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences State Key Laboratory of Earth Surface Processes and Resource Ecology Beijing Normal University

Being an important desert riparian forest in the lower reaches of the Heihe River Basin, Populus euphratica Oliv. forest functions as a natural barrier in maintaining and preserving the stability of local oases. Accordingly, accurately estimating the water use of P. euphratica is important for vegetation protection and water resource allocation. To date, little data are available for evaluating the hysteretic effects between sap flow and environmental variables, and for estimating the water use of desert riparian forest. In this study, we measured the sap flow velocity （Vs） of P. euphratica using the heat ratio method during the growing season of 2012. Based on the response of Vs to solar radiation （R,） and vapor pressure deficit （VPD）, we estimated the hourly Vs and daily Vs using the multivariable linear regression and a modified Jarvis-Stewart （JS） model, respectively. Hysteretic response of Vs to environmental variables was then evaluated using a sap flow model. We found the thresholds of V, responses to Rs and VPD at both hourly and daily scales during the growing season, and successfully estimated the seasonal variations of hourly V, and daily Vs using the JS model. At an hourly scale, the maximum V~ occurred earlier than the maximum VPD by approximately 0.5 h but later than the maximum R, by approximate 1.0 h. At a daily scale, the maximum Vs lagged behind the maximum VPD by approximately 2.5 h while occurred earlier than the maximum Rs by approximately 2 h. However, hysteretic response of V, was weakened when Rs and VPD were measured together using the JS model at both hourly and daily scales. Consequently, short-term and intensive field campaigns, where Vs and environmental variables can be measured, may be used to estimate short-run sap flow and stand transpiration using only two environmental variables.

关键词： sap flow solar radiation vapor pressure deficit Jarvis-Stewart model hysteresis

High-performance violet phosphorus photodetectors with van der Waals-assisted contacts

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Science China(Physics,Mechanics & Astronomy) 2023年第9期66卷 86-93页

作者： Hao Wang Shuling Liu Peng Wang Haonan Ge Yue Chen Hailu Wang tengfei Xu Jiaxiang Guo Yuanchen Zou Wenrui Wei Ruiqi Jiang Fang Wang Piotr Martyniuk Jinshui miao Weida Hu State Key Laboratory of Infrared Physics Shanghai Institute of Technical PhysicsChinese Academy of SciencesShanghai 200083China School of Physics and Photoelectric Engineering Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhou 310024China Institute of Applied Physics Military University of TechnologyWarsaw 00-908Poland Frontier Institute of Chip and System Fudan UniversityShanghai 200438China School of Microelectronics Shanghai UniversityShanghai 201800China University of Chinese Academy of Sciences Beijing 100049China

Black phosphorus(BP) as a narrow-bandgap two-dimensional semiconductor material has been extensively studied. And the allotrope violet phosphorus(VP) exhibits wide bandgap properties extending the application in the visible light band. However,due to the Schottky barrier of metal/semiconductor contacts(M/S), further device application of VP is limited. Here, VP-based photodetectors with van der Waals-assisted contact were demonstrated, achieving quasi-Ohmic M/S contacts. The output characteristics in dark conditions show ultralow current at the pA level. And the device exhibits a high current on-off ratio of 10~5and a fast response speed of 8.4 ms. Furthermore, we constructed the first allotropic photodetector based on BP and VP heterojunction. The device maintains ultralow dark current(~ pA) while exhibiting faster carrier transport, with 945 μs response time and polarization detection capability. These results offer an effective way to study the optoelectronic properties of VP and promote the study of allotropic heterojunction devices.

关键词： violet phosphorus two-dimensional materials photodetectors Ohmic contact allotropic heterojunction

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