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| 1 | Fuzzy Control of LED Tunnel Lighting and Energy Conservation显示文摘Current highway tunnel lighting control systems are often manually controlled,resulting in significant energy waste.This article designs a fuzzy control algorithm for tunnel lighting energy control systems.The system uses LED (Light Emitting Diode) lighting,so the fuzzy control algorithm is designed for LED lights.The traffic and the natural illumination level are used as parameters in the intelligent lighting control algorithm.This system has been deployed in the Lengshui tunnel on the 49th provincial highway of Zhejiang province and operated for more than six months.The performance results show that the energy conservation system provides sufficient lighting levels for traffic safety with significant energy conservation. | Hong Zeng Jian Qiu Xingfa Shen Guojun Dai Peng Liu Shuping Le | 2011 | Tsinghua Science and Technology2011，16，6： | 17 |
| 2 | Correction of Observation Interference on Z component of Geomagnetic Field From DC Power Lines显示文摘为减小直流输电线路对地磁场观测的干扰,采用数学计算的方法精确求解了线路对地磁Z分量的干扰水平。以观测点为原点建立了地磁仪器观测点坐标系,推导了观测点坐标系各坐标轴在地心坐标系中的单位矢量表达式。根据空间矢量点积的定义,得到了空间电流磁场矢量投影到地磁Z分量方向的求解公式。利用推导的公式和直流线路电流磁场三维计算模型,最终求得直流线路对地磁Z分量观测的干扰水平。由此,开发了"直流线路对地磁观测干扰校正系统",并开展了地磁台站和野外联合地磁观测干扰实验。结果表明,直流线路和地磁观测台站距离不超过10km时,提出的数学模型和计算方法误差不超过5%。 | TANG Bo ZHANG Jiangong MENG Suimin LIU Xingfa DENG Changzheng | 2012 | 中国电机工程学报2012，32，30： | 8 |
| 3 | Forest NPP estimation based on MODIS data under cloudless condition显示文摘Based on light-use efficiency model, an MODIS-derived daily net primary production (NPP) model was developed. In this model, a new model for the fraction of photosynthetically active radiation absorbed by vegetation (FPAR) is developed based on leaf area index (LAI) and albedo parameters, and a pho- tosynthetically active radiation (PAR) is calculated from the combination of Bird's model with aerosol optical thickness and water vapor derived from cloud free MODIS images. These two models are inte- grated into our predicted NPP model, whose most parameters are retrieved from MODIS data. In order to validate our NPP model, the observed NPP in the Qianyanzhou station and the Changbai Mountains station are used to compare with our predicted NPP, showing that they are in good agreement. The NASA NPP products also have been downloaded and compared with the measurements, which shows that the NASA NPP products underestimated NPP in the Qianyanzhou station but overestimated in the Changbai Mountains station in 2004. | CHEN LiangFu GAO YanHua LI Li LIU QinHuo GU XingFa | 2008 | Science China Earth Sciences2008，51，3： | 7 |
| 4 | Development in Researches on Reradiation Interference from UHV Power Lines显示文摘Reradiation interference(RRI) from ultra high voltage(UHV) power lines has become a hotspot for researches in electromagnetic(EM) interference between UHV power grids and adjacent radio stations.The mechanism of RRI,numerical simulations,methods of protecting distance calculation,and resonance characteristics of RRI are reviewed in this paper using results of works reported by IEEE and Chinese publications.We conclude in this review that RRI at short and medium wavelengths can be simulated using method of moment(MoM) and two commonly used models,the wire model and the surface model,which have different applicable conditions.We indicate that the accurate simulation of RRI at higher frequencies using uniform geometrical theory of diffraction is still beyond our capability because it requires studies of the relative simulation methods.We also suggest that further researches of the mechanism of RRI and the prediction of resonance frequencies above 1.7 MHz are necessary for dealing with the interference between the existing power lines and radio stations because resonance frequencies proposed by IEEE are less than 1.7 MHz. | TANG Bo ZHAO Zhibin ZHANG Jiangong LIU Xingfa CHEN Bin | 2013 | 高电压技术2013，39，10： | 3 |
| 5 | A twin-channel difference model for cross-calibration of thermal infrared band显示文摘Based on the conduction and transformation of the thermal infrared radiative transfer equation of water target,a twinchannel difference model(DM) was proposed to improve the calibration precision by conquering the limitation that the atmospheric condition when image is acquiring cannot be truly obtained in the traditional radiometric simulation calibration method.The analysis of surface,atmosphere and top-of-atmosphere(TOA) radiative energy decomposition demonstrated that the apparent TOA radiance of the uncalibrated channel is the differential combination of two reference channels.The DM avoids impacts from atmospheric temperature and density.The only impact is from water vapor(WV) content.Based on the fitting error analysis of 742 mid-latitude atmospheric profiles(column WV content:0-5×10 3 atm cm) selected from TIGR database,the DM is insensitive to WV content.The maximum error is less than 0.2 K when the view zenith angels(VZAs) of reference channels and uncalibrated channel are less than 30.The error becomes 0.3 K when VZAs range from 30 to 40 and 0.6 K when VZAs are in 40-50.Because the uncertainty increases when VZAs are larger than 50,the best range of VZAs is 30-50.The vicarious calibration results at Lake Qinghai field indicated that the calibration precision of the DM cross-calibration by using MODIS bands 31 and 32 as reference channels to calibrate IRS band 08 is similar to that of vicarious calibration.Therefore,the DM is a reliable alternative tool for sensor on-orbit calibration and validation with high precision and frequency. | LI JiaGuo GU XingFa YU Tao LI XiaoYing GAO HaiLiang LIU Li XU Hui | 2012 | Science China(Technological Sciences)2012，55，7： | 2 |
| 6 | Comparison of droplet distributions from fluidic and impact sprinklers显示文摘To adapt to the trend toward low-energy precision irrigation, the droplet distributions for two new prototype sprinklers, outside signal sprinkler(OS) and fluidic sprinkler(FS), were compared with impact sprinkler(IS). A laser precipitation monitor was used to measure the droplet distributions. Droplet size and velocity distributions were tested under four operating pressures for nozzles 1.5 m above the ground. For the operating pressures tested, the mean OS, FS and IS droplet diameters ranged from 0 to 3.4, 0 to 3.5, 0 to 4.0 mm, respectively.The mean OS and FS droplet velocities ranged from 0 to6.3 m$s–1, whereas IS ranged from 0 to 6.3 m$s–1. Being gas-liquid fluidic sprinklers, droplet distributions of the OS and FS were similar, although not identical. IS mostly produced a 0.5 mm larger droplet diameter and a 0.5 m$s–1greater velocity than OS and FS. A new empirical equation is proposed for determination of droplet size for OS and FS, which is sufficiently accurate and simple to use. Basic statistics for droplet size and velocity were performed on data obtained by the photographic methods. The mean droplet diameter(arithmetic, volumetric and median)decreased and the mean velocity increased in operating pressure for the three types of sprinkler. | Xingye ZHU Shouqi YUAN Junping LIU Xingfa LIU | 2015 | Frontiers of Agricultural Science and Engineering2015，2，1： | 1 |
| 7 | Relating soil surface moisture to reflectance 显示文摘 | Liu Weidong F Baret Gu Xingfa | 2002 | Remote sensing of the environment2002，81，23： | 1 |
| 8 | Relating soil surface moisture to reflectance显示文摘 | LIU WEIDONG BARET F GU XINGFA | 2002 | Remote Sensing of Environment2002，81，： | 1 |
| 9 | Relating soil surface moisture to reflectance 显示文摘 | Liu Weidong Baret F Gu Xingfa | 2002 | Remote Sensing of Environment2002，81，： | 1 |
| 10 | Relating soil surface moisture to reflectance显示文摘 | Liu Weidong F. Baret Gu Xingfa Tong Qingxi Zheng Lanfen Zhang Bing | 2002 | Remote Sensing of Environment2002，，2： | 1 |
| 11 | Relating soil surface moisture to reflectance显示文摘 | Liu Weidong Baret F Gu Xingfa | 2002 | Remote Sensing of Environment2002，81，： | 1 |
| 12 | Highly delocalized endohedral metal in Gd@C2v(9)-C82 metallofullerenes co-crystallized with α-Se显示文摘 | Cheng Li Xuejiao J. Gao Huanli Yao Huan Huang Rongli Cui Xihong Guo Lele Zhang Bing Liu Binggang Xu Weiqun Shi Jinquan Dong Lai Feng Xingfa Gao Baoyun Sun | 2018 | Nano Research2018，11，4： | 0 |
| 13 | The influence of rainfall on PR radar measurement of ocean surface wind speed and its calibration显示文摘Rain can significantly degrade the wind vector retrieval from Precipitation Radar(PR) by three mechanisms, namely, two-way rain attenuation, rain volume-backscattering, and ocean surface roughening from the rain splash effect. Here we first derive the radar equation for PR in rainy conditions. Then we use the rain attenuation model for Ku band, volume backscatter model for spherical raindrops and PR–TMI(TRMM Microwave Imager, TMI) matchup datasets from June to August in 2010 to solve the radar equation, and quantitatively analyze the influence of rainfall on PR radar measurement of ocean surface wind speed. Our results show that the significant effect of rain on radar signal is dominated by two-way rain attenuation and rain splash effect, and the effect of rain volume-backscattering is relatively the weakest, which can even be neglected in rain-weak conditions. Moreover, both the two-way rain attenuation and rain splash effect increase with the increasing of integration rain rate and incident angle. Last, we combine volume-backscattering effect and splash effect into a simple phenomenological model for rain calibration and select three typhoon cases from June to August in 2012 to verify the accuracy of this model. Before calibration, the mean difference and mean square error(MSE) between PR-observed ? 0 and wind-induced ? 0 are about 2.95 dB and 3.10 dB respectively. However, after calibration, the mean difference and MSE are reduced to 0.64 dB and 1.61 dB respectively. The model yields an accurate calibration for PR near-nadir normalized radar cross section(NRCS) in rainy conditions. | LIU Peng GU XingFa YU Tao LI Juan DONG Wen | 2014 | Science China Earth Sciences2014，57，10： | 0 |
| 14 | Error-space estimate method for generalized synergic target tracking显示文摘To improve the tracking accuracy and stability of an optic-electronic target tracking system,the concept of generalized synergic target and an algorithm named error-space estimate method is presented.In this algorithm,the motion of target is described by guide data and guide errors,and then the maneuver of the target is separated into guide data and guide errors to reduce the maneuver level.Then state estimate is implemented in target state-space and error-space respectively,and the prediction data of target position are acquired by synthesizing the filtering data from target state-space according to kinematic model and the prediction data from errorspace according to guide error model.Differing from typical multi-model method,the kinematic and guide error models work concurrently rather than switch between models.Experiment results show that the performance of the algorithm is better than Kalman filter and strong tracking filter at the same maneuver level. | Ming CEN Chengyu FU Ke CHEN Xingfa LIU | 2009 | Frontiers of Electrical and Electronic Engineering in China2009，4，1： | 0 |
| 15 | Jacobi Spectral Collocation Method Based on Lagrange Interpolation Polynomials for Solving Nonlinear Fractional Integro-Differential Equations显示文摘In this paper,we study a class of nonlinear fractional integro-differential equations,the fractional derivative is described in the Caputo sense.Using the properties of the Caputo derivative,we convert the fractional integro-differential equations into equivalent integral-differential equations of Volterra type with singular kernel,then we propose and analyze a spectral Jacobi-collocation approximation for nonlinear integro-differential equations of Volterra type.We provide a rigorous error analysis for the spectral methods,which shows that both the errors of approximate solutions and the errors of approximate fractional derivatives of the solutions decay exponentially in L^(∞)-norm and weighted L^(2)-norm. | Xingfa Yang Yin Yang Yanping Chen Jie Liu | 2018 | Advances in Applied Mathematics and Mechanics2018，10，6： | 0 |
| 16 | ANALYSIS OF SPECTRAL CHARACTERISTICS AMONG DIFFERENT SENSORS BY USE OF SIMULATED RS IMAGES显示文摘This research,by use of RS image_simulating method,simulated apparent reflectance images at sensor level and ground_reflectance images of SPOT_HRV,CBERS_CCD,Landsat_TM and NOAA14_AVHRR’s corresponding bands.These images were used to analyze sensor’s differences caused by spectral sensitivity and atmospheric impacts.The differences were analyzed on Normalized Difference Vegetation Index(NDVI).The results showed that the differences of sensors’ spectral characteristics cause changes of their NDVI and reflectance.When multiple sensors’ data are applied to digital analysis,the error should be taken into account.Atmospheric effect makes NDVI smaller,and atmospheric correction has the tendency of increasing NDVI values.The reflectance and their NDVIs of different sensors can be used to analyze the differences among sensor’s features.The spectral analysis method based on RS simulated images can provide a new way to design the spectral characteristics of new sensors. | YE Zetian GU Xingfa LIU Xianlin WANG Zhimin | 2000 | Geo-Spatial Information Science2000，3，2： | 0 |
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