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4篇 您的检索式:作者名="FENG Lianfeng"
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1The effect of nanohybrid materials on the pour-point and viscosity depressing of waxy crude oil显示文摘The pipeline transportation of waxy crude oil is a problem both at home and abroad.In this paper,a novel nanohybrid pour-point depressant (PPD) was used to decrease the pour point and viscosity of waxy crude oil.The pour point and apparent viscosity of waxy crude oil was decreased significantly upon addition of the nanohybrid PPD,and the long-term stability of the nanohybrid PPD was superior to that of a conventional ethylene-vinyl acetate copolymer PPD.Polarized optical microscopy and X-ray diffraction were used to study the effect of the nanohybrid PPD on the crystallization of crude oil.Addition of the nanohybrid PPD reduced the amount of wax crystals,prevented their aggregation,and reduced the temperature at which the crude oil started to crystallize.The significant effect of this nanohybrid PPD on the pour point and viscosity depressing of crude oil is of great importance for facilitating the safe,efficient and energy-minimized transportation of waxy crude oil.WANG Feng ZHANG DongMin DING YanFen ZHANG LiXin YANG MingShu JIANG BaoLiang ZHANG ShiMin AI MuYang LIU GuangWen ZHI ShuJie HUO LianFeng OUYANG Xin LI Li 2011Chinese Science Bulletin2011,56,1:9
2A Single-Site Positioning Method Based on TOA and DOA Estimation Using Virtual Stations in NLOS Environment显示文摘This paper presents a single-site positioning method based on the joint estimation of propagation time-of-arrival(TOA) and direction-of-arrival(DOA), with the assist of virtual stations in the typical non-line-of-sight(NLOS) environment. Consider the influence of multipath noise on the positioning performance, the proposed method firstly presents a modified high-resolution estimation technique called Multipath noise Limiting Matrix Pencil(MLMP) algorithm to achieve the TOA/DOA estimations, in which the matrix pencil and matrix enhancement process are implemented to deal with the measurements from the uniform linear array(ULA) receiver. Meanwhile, the subspace dimension estimation is improved via an adaptive threshold, for enhancing the performance of high-resolution techniques in low signal-noise-ration(SNR) situation. Next the proposed method generates virtual stations utilizing the known floor plan of surrounding reflectors, and adopts a weighted Least Square(WLS) position estimator to calculate the required position, combining the TOA/DOA estimations with the location of virtual stations. Simulations are conducted to evaluate the proposed method under NLOSconditions, and the results show that comparing with the multipath fingerprinting scheme, the proposed method has better performance in various simulation scenarios.Rui Zhang Weiwei Xia Feng Yan Lianfeng Shen 2019China Communications2019,16,2:9
3VEHICULAR NODE POSITIONING BASED ON DOPPLER-SHIFTED FREQUENCY MEASUREMENT ON HIGHWAY显示文摘Vehicular node positioning needs to be quick and precise on highway for safety considera-tion.In this paper,we present a novel and practical vehicular node positioning method which can achieve a higher accuracy and more reliability than the existing global-positioning-system-based po-sitioning solutions by making use of Doppler-shifted frequency measurements taken by vehicular node itself.This positioning method uses infrastructure nodes which are placed on the roadside every several kilometers as radiation sources to estimate the relative distances of vehicle to the infrastructure node.Through coordinate conversion,we get the absolute coordinates of vehicular node based on known absolute coordinates of infrastructure node.We also analyze the optimal distance of neighbor infra-structure nodes in order to ensure a high accuracy.In addition,simulation results demonstrate that the accuracy of our method with Extended Kalman Filtering(EKF) is superior to the method without EKF.Xu Bo Shen Lianfeng Yan Feng 2009Journal of Electronics(China)2009,26,2:3
4Power consumption of inner-outer helical ribbon impellers in viscous Newtonian and non-Newtonian fluids显示文摘WANG Jiajun FENG Lianfeng GU Xueping 2000Chem Eng Sci2000,55,12:1
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