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Frequency offset estimation based on peak power ratio in LTE system

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The Journal of China Universities of Posts and Telecommunications 2013年第6期20卷 49-54页

作者： WANG Jun GUAN bao LIU Shou-yin xie Wen-wu Department of Electronics and Communication Engineering Central China Normal University Department of LTE Wuhan Hongxin Telecom. Technologies CO.LTD

Orthogonal frequency division multiplexing （OFDM） is one of the key techniques for long term evolution （LTE） system. Frequency offset estimation of OFDM is an essential issue. Especially in the high-speed environment, the frequency offset will become large. Based on the features of LTE uplink physical random access channel （PRACH）, this paper proposes a new frequency offset algorithm by using peak power ratio to enlarge the range of frequency offset estimation. According to the relation between frequency offset and the power delay profile （PDP）, the ratio of the peak power of the PDP at the main window to that at the negative window or positive window is utilized to estimate frequency offset. Simulation results show that the new proposed algorithm extends the estimation range of frequency offset from 1 000 Hz to 1 250 Hz. Meanwhile the accuracy of frequency offset estimation is almost not lost. Particularly in low signal noise ratio （SNR）, the new algorithm has lower mean square error （MSE） compared with traditional phase differential algorithm.

关键词： frequency offset estimation LTE peak power ration PDP

Current Reversal Due to Coupling Between Asymmetrical Driving Force and Ratchet Potential

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Communications in Theoretical Physics 2006年第4期45卷 637-640页

作者： AI bao-Quan xie Hui-Zhang LIU Liang-Gang School of Physics and Telecommunication Engineering South China Normal University Guangzhou 510631 China Department of Physics South China University of Technology Guangzhou 510641 China Department of Physics Zhongshan University Guangzhou 510275 China

Transport of a Brownian particle moving in a periodic potential is investigated in the presence of an asymmetric unbiased external force. The asymmetry of the external force and the asymmetry of the potentlal are the two ways of inducing a net current. It is found that the competition of the spatial asymmetry of potential with the temporal asymmetry of the external force leads to the phenomena like current reversal The competition between the two opposite driving factors is a necessary but not a sufficient condition for current reversals.

关键词： current reversal correlation ratchet competition

Spatiotemporal variations of PM_(2.5) and PM_(10) concentrations between31 Chinese cities and their relationships with SO_2,NO_2,CO and O_3

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Particuology 2015年第3期13卷 141-149页

作者： Yangyang xie Bin Zhao lin Zhang Rong Luo Department of Building Science School of ArchitectureTsinghua University Department of Electronic Engineering Tsinghua University

The variations of mass concentrations of PM2.5, PMl0, SO2, NO2, CO, and 03 in 31 Chinese provincial capital cities were analyzed based on data from 286 monitoring sites obtained between March 22, 2013 and March 31,2014. By comparing the pollutant concentrations over this length of time, the characteristics of the monthly variations of mass concentrations of air pollutants were determined. We used the Pearson correlation coefficient to establish the relationship between PM2.5, PM10, and the gas pollutants. The results revealed significant differences in the concentration levels of air pollutants and in the variations between the different cities. The Pearson correlation coefficients between PMs and NO2 and SO2 were either high or moderate （PM2.s with NO2： r = 0.256-0.688, mean r = 0,498：PM10 with NO2： r = 0.169-0.713, mean r=0.493; PM2.5 with SO2： r=0.232-0.693, mean r=0.449; PM10 with SO2： r=0.131-0.669, mean r = 0.403）. The correlation between PMs and CO was diverse （PM2.5： r = 0.156-0.721, mean r = 0.437; PMl0： r= 0.06-0.67, mean r= 0.380）. The correlation between PMs and 03 was either weak or uncorrelated （PM2.s： r= -0,35 to 0.089, mean r= -0.164; PM10： r= -0.279 to 0.078, mean r= -0.127）, except in Haikou （PM2.5： r=0.500; PM10： r=0,509）.

关键词： PM2.5PM40 Atmospheric air pollutantIndoor environmentOutdoor environment

Unsupervised content-preserving transformation for optical microscopy

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Light(Science & Applications) 2021年第3期10卷 390-400页

作者： Xinyang Li Guoxun Zhang Hui Qiao Feng bao Yue Deng Jiamin Wu Yangfan He Jingping Yun Xing lin Hao xie Haoqian Wang Qionghai Dai Department of Automation Tsinghua UniversityBeijing 100084China Tsinghua Shenzhen International Graduate School Tsinghua UniversityShenzhen 518055China Institute for Brain and Cognitive Sciences Tsinghua UniversityBeijing 100084China School of Astronautics Beihang UniversityBeijing 100191China Beijing Advanced Innovation Center for Big Data and Brain Computing Beihang UniversityBeijing 100191China Department of Pathology Sun Yat-sen University Cancer CenterGuangzhou 510060China State Key Laboratory of Oncology in South China Guangzhou 510060China Collaborative Innovation Center for Cancer Medicine Guangzhou 510060China Beijing Innovation Center for Future Chips Tsinghua UniversityBeijing 100084China

The development of deep learning and open access to a substantial collection of imaging data together provide a potential solution for computational image transformation,which is gradually changing the landscape of optical imaging and biomedical ***,current implementations of deep learning usually operate in a supervised manner,and their reliance on laborious and error-prone data annotation procedures remains a barrier to more general ***,we propose an unsupervised image transformation to facilitate the utilization of deep learning for optical microscopy,even in some cases in which supervised models cannot be *** the introduction of a saliency constraint,the unsupervised model,named Unsupervised content-preserving Transformation for Optical Microscopy(UTOM);can learn the mapping between two image domains without requiring paired training data while avoiding distortions of the image *** shows promising performance in a wide range of biomedical image transformation tasks,including in silico histological staining,fluorescence image restoration,and virtual fluorescence *** evaluations reveal that UTOM achieves stable and high-fidelity image transformations across different imaging conditions and *** anticipate that our framework will encourage a paradigm shift in training neural networks and enable more applications of artificial intelligence in biomedical imaging.

关键词： transformation preserving image

Fault-tolerant finite-time dynamical consensus of double-integrator multi-agent systems with partial agents subject to synchronous self-sensing function failure

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Chinese Physics B 2022年第12期31卷 719-725页

作者： Zhi-Hai Wu lin-Bo xie Engineering Research Center of Internet of Things Technology Applications of MOE School of Internet of Things EngineeringJiangnan UniversityWuxi 214122China

This paper investigates fault-tolerant finite-time dynamical consensus problems of double-integrator multi-agent systems(MASs)with partial agents subject to synchronous self-sensing function failure(SSFF).A strategy of recovering the connectivity of network topology among normal agents based on multi-hop communication and a fault-tolerant finitetime dynamical consensus protocol with time-varying gains are proposed to resist synchronous *** is proved that double-integrator MASs with partial agents subject to synchronous SSFF using the proposed strategy of network topology connectivity recovery and fault-tolerant finite-time dynamical consensus protocol with the proper time-varying gains can achieve finite-time dynamical *** simulations are given to illustrate the effectiveness of the theoretical results.

关键词： multi-agent systems synchronous self-sensing function failure finite-time dynamical consensus network topology connectivity recovery

Effect of gradient temperature rolling process on promoting crack healing in Q500 heavy plates

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International Journal of Minerals,Metallurgy and Materials 2020年第3期27卷 354-361页

作者： Zhao-hai Gao Wei Yu Xu Chen bao-sheng xie Qing-wu Cai Collaborative Innovation Center of Steel Technology University of Science and Technology BeijingBeijing 100083China National Engineering Research Center of Advanced Rolling University of Science and Technology BeijingBeijing 100083China Hunan Valin Rolling Steel Sheet Co.Ltd LoudiHunan 417000China

To ensure the quality of heavy plate products as determined by ultrasonic inspection, it is necessary to effectively control defects such as cracks and shrinkage cavities in heavy plates. Generally, some defects such as large size cracks exist due to insufficient deformation in the center of traditionally rolled plates. Compared with the traditional rolling process, gradient temperature rolling(GTR) process can effectively increase deformation inside heavy plates. In this study, the effect of GTR on crack healing was analyzed through a comparison experiment with the uniform temperature rolling(UTR). The results show that the GTR process could increase the plastic strain inside the heavy plate and effectively promote the healing process of the preset cracks. The degrees of crack healing at the center and quarter thickness position of the steel plate via GTR were greater than twice those of the plate via UTR. The GTR process can significantly reduce the internal defects of heavy plates and improve the defect detection level of heavy plate products. Also, The GTR process results in the formation of new crystal grains in the crack region, which is crucial to crack healing.

关键词： heavy plates multilayer pack rolling crack healing behavior hot rolling process

CuS nanoenzyme against bacterial infection by in situ hydroxyl radical generation on bacteria surface

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Rare Metals 2023年第6期42卷 1899-1911页

作者： Zhao Li Cheng-Jia xie Xiao-Wei Ren Qun Zhang bao-Jin Ma Department of Tissue Engineering and Regeneration School and Hospital of StomatologyCheeloo College of MedicineShandong University&Shandong Key Laboratory of Oral Tissue Regeneration&Shandong Engineering Laboratory for Dental Materials and Oral Tissue Regeneration&Shandong Provincial Clinical Research Center for Oral DiseasesJinan250012China Jinan Food and Drug Inspection and Testing Center Jinan250010China

Nanoenzyme-mediated antibacterial strategies have been widely exploited to overcome the shortcomings(such as drug resistance and mild-to-severe side effects) of antibiotic *** peroxidase-like activity of nanoenzymes possesses great potential against bacterial infection by the generation of hydroxyl radical(·OH) in the specific ***,the lifetime of-OH is extremely short,and a large amount of the ·OH generated within the infection microenvironment cannot come into contact with bacteria quickly enough,thus resulting in low treatment ***,chitosan-oligosaccharide-modified CuS nanoparticles possessing positive charges(PCuS NPs) were prepared using a one-pot *** NPs exhibited efficient peroxidase-like ***,the PCuS NPs can combine with bacteria via electrostatic *** direct contact between the PCuS NPs and bacteria enabled the generation of ·OH in situ on the bacterial surface,ultimately leading to a high antibacterial efficacy at a low concentration in the presence of H_(2)O_(2).At an effective antibacterial concentration,the PCuS NPs exhibited high ***,in vivo results revealed that PCuS NPs not only decreased the size of abscesses but also reduced inflammation and promoted collagen fiber ***,PCuS NPs possess great potential against bacterial infection via in situ ·OH generation based on electrostatic attraction.

关键词： Antibacterial CuS Nanoenzyme In situ ·OH generation Electrostatic attraction

Defect-rich MoS2 nanowall catalyst for efficient hydrogen evolution reaction

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Nano Research 2017年第4期10卷 1178-1188页

作者： Junfeng xie Haichao Qu Jianping Xin Xinxia Zhang Guanwei Cui Xiaodong Zhang Jian bao Bo Tang Yi xie College of Chemistry Chemical Engineering and Materials Science Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong Key Laboratory of Molecular and Nano Probes Ministry of Education Institute of Molecular and Nano Science Shandong Normal University Jinan 250014 China Hefei National Laboratory for Physical Sciences at the Microscale Department of Chemistry University of Science and Technology ot China Hefei 230026 China

Designing efficient electrocatalysts for the hydrogen evolution reaction （HER） has attracted substantial attention owing to the urgent demand for clean energy to face the energy crisis and subsequent environmental issues in the near future. Among the large variety of HER catalysts, molybdenum disulfide （MoS2） has been regarded as the most famous catalyst owing to its abundance, low price, high efficiency, and definite catalytic mechanism. In this study, defect-engineered MoS2 nanowall （NW） catalysts with controllable thickness were fabricated and exhibited a significantly enhanced HER performance. Benefiting from the highly exposed active edge sites and the rough surface accompanied by the robust NW structure, the defect-rich MoS2 NW catalyst with an optimized thickness showed an ultralow onset overpotential of 85 mV, a high current density of 310.6 mA·cm^-2 at η = 300 mV, and a low potential of 95 mV to drive a 10 mA·cm^-2 cathodic current. Additionally, excellent electrochemical stability was realized, making this freestanding NW catalyst a promising candidate for practical water splitting and hydrogen production.

关键词： molybdenum disulfide (MoS2) nanowall water splitting electrocatalysis hydrogen evolution reaction

Cross-linkable fullerene interfacial contacts for enhancing humidity stability of inverted perovskite solar cells

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Rare Metals 2021年第7期40卷 1691-1697页

作者： Ming-Wei An Zhou Xing bao-Shan Wu Fang-Fang xie Shan-Yu Zheng lin-Long Deng Xu Wang Bin-Wen Chen Da-Qin Yun Su-Yuan xie Rong-Bin Huang Lan-Sun Zheng State Key Laboratory for Physical Chemistry of Solid Surfaces iChEM(Collaborative Innovation Center of Chemistry for Energy Materials)Department of ChemistryCollege of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China Pen-Tung Sah Institute of Micro-Nano Science and Technology Xiamen UniversityXiamen 361005China College of Energy Xiamen UniversityXiamen 361005China

In situ cross-linking encapsulation has been demonstrated to be an efficient strategy for enhancing the humidity stability of perovskite solar cells(PSCs).In this study,a novel cross-linkable fullerene derivative,namely1-(p-benzoate-(p-methylvinylbenzene)-indolino[2,3][60]fullerene(FPPS),was readily synthesized from commercially available building blocks in two *** FPPS was employed as an interfacial modifier on perovskite surfaces in inverted planar p-i-n *** to the fast interfacial charge extraction and efficient trap passivation,PSCs based on the cross-linked FPPS(C-FPPS)exhibited excellent *** PSCs had a top-performing power conversion efficiency(PCE)of 17.82%with negligible hysteresis,compared to the control devices without C-PFFS(16.99%).Moreover,the strong water resistance of the C-FPPS interfacial layer distinctly enhances the ambient stability of PSC devices,exhibiting a t80(the time required to reach 80%of the initial PCE)of 300 h under high-humidity *** significantly surpasses the control devices,whose t80 was only 130 *** results demonstrate that cross-linkable fullerene derivatives can be promising interfacial materials for designing high-efficiency,hysteresis-free,air-stable PSCs.

关键词： Perovskite solar cells Cross-linkable fullerene Fullerene interlayer Power conversion efficiency Humidity stability