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38篇 您的检索式:作者名="Lifeng Shen"
    题名 作者 年代 出处 被引量
1Generative Adversarial Network-Based Electromagnetic Signal Classification: A Semi- Supervised Learning Framework显示文摘Generative adversarial network(GAN)has achieved great success in many fields such as computer vision,speech processing,and natural language processing,because of its powerful capabilities for generating realistic samples.In this paper,we introduce GAN into the field of electromagnetic signal classification(ESC).ESC plays an important role in both military and civilian domains.However,in many specific scenarios,we can’t obtain enough labeled data,which cause failure of deep learning methods because they are easy to fall into over-fitting.Fortunately,semi-supervised learning(SSL)can leverage the large amount of unlabeled data to enhance the classification performance of classifiers,especially in scenarios with limited amount of labeled data.We present an SSL framework by incorporating GAN,which can directly process the raw in-phase and quadrature(IQ)signal data.According to the characteristics of the electromagnetic signal,we propose a weighted loss function,leading to an effective classifier to realize the end-to-end classification of the electromagnetic signal.We validate the proposed method on both public RML2016.04c dataset and real-world Aircraft Communications Addressing and Reporting System(ACARS)signal dataset.Extensive experimental results show that the proposed framework obtains a significant increase in classification accuracy compared with the state-of-the-art studies.Huaji Zhou Licheng Jiao Shilian Zheng Lifeng Yang Weiguo Shen Xiaoniu Yang 2020China Communications2020,17,10:8
2The electron structure and photocatalytic activity of Ti(IV) doped Bi_2O_3显示文摘Density functional theory (DFT) plays a significant role in the development of visible light responsive photocatalysts.Based on the first-principles plane-wave ultrasoft pseudopotential (USPP) method,the crystal structures of α,β,γ,and δ-Bi2O3 were optimally calculated for the total density of states (TDOS) and the partial density of states (PDOS) of Bi,O atoms.The calculation for Ti(IV) doped Bi2O3 supercell was carried out.The effects of Ti(IV)-doping on the electron structures and light absorption properties of various Bi2O3 were analyzed.The results showed that Ti 3d orbital appeared in the forbidden band of Bi2O3 and hybridized with O 2p,Bi 6p orbitals.The narrowed band gap (Eg) and red-shift of light absorption edge are responsible for the enhanced photocatalytic activity of Bi2O3.The β-Bi2O3 and Ti-doped β-Bi2O3 were prepared by a hydrothermal synthesis method.The improvement of the photocatalytic activity of Bi2O3 has also been verified by the characteristics of the UV-vis diffuse reflection spectrum and the experimental evaluation of the photocatalytic degradation of crystal violet in aqueous solution.YIN LiFeng NIU JunFeng SHEN ZhenYao SUN Ying 2011Science China Chemistry2011,54,1:7
3Spectrum Sensing via Temporal Convolutional Network显示文摘In this paper,we investigate a spectrumsensing system in the presence of a satellite,where the satellite works as a sensing node.Considering the conventional energy detection method is sensitive to the noise uncertainty,thus,a temporal convolutional network(TCN)based spectrum-sensing method is designed to eliminate the effect of the noise uncertainty and improve the performance of spectrum sensing,relying on the offline training and the online detection stages.Specifically,in the offline training stage,spectrum data captured by the satellite is sent to the TCN deployed on the gateway for training purpose.Moreover,in the online detection stage,the well trained TCN is utilized to perform real-time spectrum sensing,which can upgrade spectrum-sensing performance by exploiting the temporal features.Additionally,simulation results demonstrate that the proposed method achieves a higher probability of detection than that of the conventional energy detection(ED),the convolutional neural network(CNN),and deep neural network(DNN).Furthermore,the proposed method outperforms the CNN and the DNN in terms of a lower computational complexity.Tao Ni Xiaojin Ding Yunfeng Wang Jun Shen Lifeng Jiang Gengxin Zhang 2021China Communications2021,18,9:6
4The Construction of Active Source Repeated Monitoring in the Qilian Mountain, Gansu Province显示文摘The exciting source of the active source repeated monitoring is located in the Xiliushui Reservoir in Zhangye,Gansu Province. The system began operating normally on July 9,2015,and we had completed a period of 40 days of continuous excitation experiment before November 10,2015. Our results reveal that the airgun source has good consistency and repeatability,and the detective system of active source can record signal clearly. The construction of active source repeated exploration projects has achieved some results,which can provide valuable experience for the research of active source repeated exploration. The observation data we obtained makes it possible to follow the temporal and spatial variations of the deep structure of the Qilian Mountain areas.Zhang Yuansheng Guo Xiao Qin Manzhong Liu Xuzhou Wei Congxin Shen Xuzhang Yan Wenhua Zou Rui Yin Liang Wang Yahong Sun Dianfeng Feng Hongwu Zhang Lifeng Guo Yingxia 2016Earthquake Research in China2016,30,3:4
5Development of a model to generate a risk map in a building fire显示文摘Fire simulations and sensors are widely used in building fires,various data such as temperature,CO and CO2 concentration,visibility can be obtained by sensors and sensor-based simulation. It is important to generate a risk map based on such data so that we can use it to estimate safety of the building. In this paper,we propose a method to generate a dynamical,integrated risk map using sensor readings in a building fire. Such risk evaluation model is developed using similarity comparison between the space state and dangerous state by a likelihood distance calculating and data grouping from a two-step cluster method. The risk evaluation model considers the integrated influence on the occupants in the zone from high temperature,lack of oxygen,toxic and harmful gases and shows the relative fire risk map at certain time. Based on the simulation study,it is proved that multi-factor fire risk analysis would be more objective and accurate than single factor and two-factor risk analysis and the fire risk evaluation model can generate a risk map and provide the classification information and the whole building risk statistic results to support evacuation command and control.CHU YanYan, ZHANG Hui, SHEN ShiFei, YANG Rui & QIAO LiFeng Center for Public Safety Research, Department of Engineering Physics, Tsinghua University, Beijing 100084, China 2010Science China(Technological Sciences)2010,53,10:4
6Involvement of long non-coding RNAs in the progression of esophageal cancer显示文摘Esophageal cancer(EC)is one of the most common malignant tumors of the digestive system with high incidence and mortality rate worldwide.Therefore,exploring the pathogenesis of ECand searching for new targeted therapies are the current research hotspot for EC treatment.Long non-coding RNAs(lncRNAs)are endogenous RNAs with more than 200 nucleotides,but without proteincoding function.In recent years,lncRNAs have gradually become the focuses in the field of non-coding RNA.Some lncRNAs have been proved to be closely related to the pathogenesis of EC.Many lncRNAs are abnormally expressed in EC and participate in many biological processes including cell proliferation,apoptosis,and metastasis by inhibiting or promoting target gene expression.LncRNAs can also regulate the progression of EC through epithelial-mesenchymal transformation(EMT),which is closely related to the occurrence,development,and prognosis of EC.In this article,we review and discuss the involvement of lncRNAs in the progression of EC.Wenhua Xue Yuanyuan Zheng Zhibo Shen Lifeng Li Zhirui Fan Wenbin Wang Zijia Zhu Yunkai Zhai Jie Zhao Quancheng Kan 2021Cancer Communications2021,41,5:4
7Hypoxia-induced GBE1 expression promotes tumor progression through metabolic reprogramming in lung adenocarcinoma显示文摘Hypoxia mediates a metabolic switch from oxidative phosphorylation to glycolysis and increases glycogen synthesis.We previously found that glycogen branching enzyme(GBE1)is downstream of the hypoxia-inducible factor-1(HIF1)signaling pathway in lung adenocarcinoma(LUAD)cells;however,the molecular mechanism underlying HIF1 regulation of GBE1 expression remains unknown.Herein,the effect of GBE1 on tumor progression via changes in metabolic signaling under hypoxia in vitro and in vivo was evaluated,and GBE1-related genes from human specimens and data sets were analyzed.Hypoxia induced GBE1 upregulation in LUAD cells.GBE1-knockdown A549 cells showed impaired cell proliferation,clone formation,cell migration and invasion,angiogenesis,tumor growth,and metastasis.GBE1 mediated the metabolic reprogramming of LUAD cells.The expression of gluconeogenesis pathway molecules,especially fructose-1,6-bisphosphatase(FBP1),was markedly higher in shGBE1 A549 cells than it was in the control cells.FBP1 inhibited the tumor progression of LUAD.GBE1-mediated FBP1 suppression via promoter methylation enhanced HIF1αlevels through NF-κB signaling.GBE1 may be a negative prognostic biomarker for LUAD patients.Altogether,hypoxia-induced HIF1αmediated GBE1 upregulation,suppressing FBP1 expression by promoter methylation via NF-κB signaling in LUAD cells.FBP1 blockade upregulated HIF1α,triggered the switch to anaerobic glycolysis,and enhanced glucose uptake.Therefore,targeting HIF1α/GBE1/NF-κB/FBP1 signaling may be a potential therapeutic strategy for LUAD.Lifeng Li Li Yang Zhirui Fan Wenhua Xue Zhibo Shen Yongliang Yuan Xiangdong Sun Dan Wang Jingyao Lian Liping Wang Jie Zhao Yi Zhang 2020Signal Transduction and Targeted Therapy2020,5,1:3
8Influence of Superplasticizers on Early Age Drying Shrinkage of Cement Paste with the Same Consistency显示文摘The influence of superplasticizer(SP) on the early age drying shrinkage of cement paste with the same consistency was investigated. To conduct the test, which lasted for 72 hours, three paste mixtures were used for comparison. The 72 hours early age drying shrinkage staring from the initial setting time was measured by a clock gauge. The pore size distribution was measured by Mercury Intrusion Method. The surface tension of capillary simulation liquid and mass loss of paste were also measured. The experimental results showed that the addition of SP increased the early drying shrinkage greatly. The ratios of water evaporation and the total free water in mixtures added with SPs showed great differences. SPs fined the capillary pores of paste, and the volume of pore with diameter within 50 nm was well consistent with shrinkage rate. The addition of SPs did not raise the capillary liquid surface tension. It showed that with the volume of pore with diameter within 50 nm and the ratio of water evaporation and the total free water a tolerable shrinkage result of paste added with SP could be predicted, and the elastic modulus could have an influence on the early shrinkage. These results have never been proposed before.赖俊英 ZHANG Lifeng 钱晓倩 SHEN Chong ZHANG Jinjian 2014Journal of Wuhan University of Technology(Materials Science)2014,29,6:3
9Resistive random access memory and its applications in storage and nonvolatile logic显示文摘The resistive random access memory(RRAM) device has been widely studied due to its excellent memory characteristics and great application potential in different fields. In this paper, resistive switching materials,switching mechanism, and memory characteristics of RRAM are discussed. Recent research progress of RRAM in high-density storage and nonvolatile logic application are addressed. Technological trends are also discussed.Dongbin Zhu Yi Li Wensheng Shen Zheng Zhou Lifeng Liu Xing Zhang 2017Journal of Semiconductors2017,38,7:2
10Experimental and numerical study on instability structure of the supersonic mixing layer(M_c = 0.5)显示文摘The parameters of instability wave of supersonic mixing layer(Mc=0.5,M1=3.5/M2=1.4) are measured by flow visualization and calculated by means of two-dimensional direct numerical simulaitons of the compressible Navier-Stokes equations.In both cases of the mixing layer with harmonic disturbance or not,the comparative results indicate that the wavelength of the two-dimensional wave is equal to the vortex spacing in the streamwise direction because the difference between them is less than 1%.However,the measured convective velocity of the large-scale structure deviates from the theoretical isentropic prediction about 10%.Here the measured value confirms that Mc,2YANG WuBing ZHUANG FengGan SHEN Qing GUAN FaMing WANG Qiang YI ShiHe ZHAO YuXin HE Lin TIAN LiFeng 2009Science China(Physics,Mechanics & Astronomy)2009,52,10:2
11Synthesis of thermostable geopolymer from circulating fluidized bed combustion (CFBC) bottom ashes显示文摘Xu Hui Li Qin Shen Lifeng 2010J Hazard Mater2010,175,123:1
12SnO 2 nanoparticles@polypyrrole nanowires composite as anode materials for rechargeable lithium-ion batteries显示文摘Lifeng Cui Jian Shen Fangyi Cheng Zhanliang Tao Jun Chen 2010Journal of Power Sources2010,,:1
13Honeycomb-like g-C_(3)N_(4)/CeO_(2)-x nanosheets obtained via one step hydrothermal-roasting for efficient and stable Cr(Ⅵ) photo-reduction显示文摘Graphitic carbon nitride(g-C_(3)N_(4))-based materials are regarded as one of the most potential photocatalysts for utilizing solar energy.In this work,we reported a facile one step in-situ hydrothermal-roasting method for preparing honeycomb-like g-C_(3)N_(4)/CeO_(2) nanosheets with abundant oxygen vacancies(g-C_(3)N_(4)/CeO_(2)-x).The hydrothermal-roasting and incomplete-sealed state can(i)generate an in-situ reducing atmosphere(CO,N2,NH3) to tune the concentration of oxygen vacancies in CeO_(2);(ii) beneficial to prevent continuous growth of g-C_(3)N_(4) and results in honeycomb-like g-C_(3)N_(4)/CeO_(2)-x hybrid nanosheets.What is more,the g-C_(3)N_(4)/CeO_(2)-x photocatalyst exhibited extended photoresponse range,increased specific surface area and obviously enhanced separation efficiency of photogenerated electron-hole pairs.As a proof-of-concept application,the optimized g-C_(3)N_(4)/CeO_(2)-xnanosheets could achieve 98% removal efficiency for Cr(Ⅵ) under visible light irradiation(λ≥420 nm)within 2.5 h,which is significantly better than those of pure g-C_(3)N_(4) and CeO_(2).This work provides a new idea for more rationally designing and constructing g-C_(3)N_(4)-based catalysts for efficient extended photochemical application.Yanan Liu Zhangfeng Shen Jialing Song Huilan Qi Chaochuang Yin Xuhui Zou Qineng Xia Lifeng Cui Xi Li Yangang Wang 2020Chinese Chemical Letters2020,31,10:1
14Bi-channel near-and far-field optical vortex generator based on a single plasmonic metasurface显示文摘With the recent development of the metasurface,generating an optical vortex in optical far or near fields is realized in various ways.However,to generate vortices in both the near and far fields simultaneously is still a challenge,although it has great potential in the future compact and versatile photonic system.Here,a bi-channel optical vortex generator in both the near and far fields is proposed and demonstrated within a single metasurface,where the surface plasmon vortex and the far-field optical vortex can be simultancously generated under circularly polarized light.The ability of generating vortices with arbitrary topological charges is experimentally demon-strated,which agrces well with simulations.This approach provides great freedom to integrate different vortex generators in a single device and ofers new opprtunities for integrated optical communications,trapping,and other related fields.QIAO JIANG YANJUN BAO JING LI LIFENG TIAN ToNG CUI LIN SUN BOWEN DU BOWEN LI BENFENG BAI JIA WANG HONGBO SUN Bo SHEN HAN ZHANG FENG LIN XING ZHU ZHEYU FANG 2020Photonics Research2020,8,6:1
15Multiple pH induced morphological changes in aggregates of polystyrene & poly(4-vinylpyridine) in DMF/H2 O rnixtures显示文摘Shen Hongwei Zhang Lifeng Eisenberg A 1999Journal of American Chemistry Society1999,121,12:1
16Low-rcactive circulating fluidized bed combustion( CFBC ) fly ashes as source material for geopolymer synthesis 显示文摘Hui Xu Qin Li Lifeng Shen etc 2010Waste Management2010,,30:1
17Synthesis of thermostable geopoly- mer from circulating fiuidized bed combustion ( CFBC ) bottom ashes 显示文摘Hui Xu Qin Li Lifeng Shen etc 2010Journal of Hazardous Materials2010,,175:1
18Multi-category support vector machines, feature selection, and solution path显示文摘Wang Lifeng Shen Xiaotong 2006Statistica Sini- ca2006,16,:1
19Low-reactive circulating fluidized bed eombustion(CFBC) fly ashes as source material for geopolymer synthesis 显示文摘Xu H Li Q Shen Lifeng 2010Waste Management2010,30,1:1
20Pressure-induced Lifshitz transition in the type Ⅱ Dirac semimetal PtTe_2显示文摘Numerous exotic properties have been discovered in Dirac Semimetals(DSMs) and Weyl Semimetals(WSMs). In a given DSM/WSM, the Dirac/Weyl nodes usually coexist with other bulk states, making their respective contribution elusive. In this work, we distinguish the role of bulk states from the tilted Dirac nodes on the transport properties in DSMs. Specifically, we applied pressure to a type-II DSM material, PtTe2, and studied its pressure modified electronic and lattice structure systematically by using in situ transport measurements and X-ray diffraction(XRD). A pressure-induced transition at about 20 GPa is revealed in the transport properties, while the layered lattice structure is robust against pressure as illustrated in XRD measurement results.Density functional theory(DFT) calculations suggest that this is originated from the Lifshitz transition in the bulk states. Our findings provide evidence to identify the bulk states' influence on transport from the topologically-protected DSM states in the DSM material.FengLiang Liu JiaHeng Li KeNan Zhang Shang Peng HuaQing Huang MingZhe Yan NaNa Li Qian Zhang SongHao Guo XuJie Lü Peng Cai LiFeng Yin ShuYun Zhou WenHui Duan Jian Shen WenGe Yang 2019Science China(Physics,Mechanics & Astronomy)2019,62,4:1
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