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| 1 | A Harmonic Compensation Approach for Interlinking Voltage Source Converters in Hybrid AC-DC Microgrids with Low Switching Frequency显示文摘In recent years,the hybrid AC-DC microgrid has been well accepted as it combines the advantages of both AC and DC systems.As the microgrid contains both DC sub-grids and AC sub-grids,interlinking DC-AC converters are essential.Meanwhile,considering the nonlinear AC loads may deteriorate the voltage quality of the AC bus,embedding an ancillary harmonic compensation function to the interlinking converters is promising.However,the conventional harmonic control methods used for active power filters(APFs)may not be suitable for the interlinking converters due to the main purpose of it is to exchange real and reactive power between the DC and AC sub-grids.The switching frequency is preferred to be lower than the APFs when the capacity of the microgrid is large.At low switching frequency,harmonic compensation performance or even the system stability may be affected.In this paper,a harmonic compensation approach suitable for hybrid AC-DC interlinking converters at low switching frequency is proposed.Through feeding the PWM reference signal with the harmonic compensation component directly to avoid the multi-loop control path of the fundamental component,the proposed method can achieve the effective harmonics compensation without being limited by the closed-loop control bandwidth.The proposed method,modeling approaches,stability analysis,as well as detailed virtual impedance design are presented.Experimental verification is also provided. | Hao Tian Xiaohan Wen Yun Wei Li | 2018 | CSEE Journal of Power and Energy Systems2018，4，1： | 3 |
| 2 | Changes in Vegetation and Assessment of Meteorological Conditions in Ecologically Fragile Karst Areas显示文摘Meteorological conditions have an important impact on changes of vegetation in ecologically fragile karst areas.This study aims to explore a method for quantitative evaluation of these meteorological conditions. We analyzed the changing trend of vegetation during 2000–2018 and the correlations between vegetation changes and various meteorological factors in karst rocky areas of Guangxi Zhuang Autonomous Region, China. Key meteorological factors in vegetation areas with varying degrees of improvement were selected and evaluated at seasonal timescale. A quantitative evaluation model of comprehensive influences of meteorological factors on vegetation was built by using the partial least-square regression(PLS). About 91.45% of the vegetation tended to be improved, while only the rest 8.55% showed a trend of degradation from 2000 to 2018. Areas with evident vegetation improvement were mainly distributed in the middle and northeast, and those with obvious vegetation degradation were scattered. Meteorological factors affecting vegetation were significantly different among the four seasons. Overall, high air humidity, small temperature difference in spring and autumn, and low daily minimum temperature and air pressure were favorable conditions. Low temperature in winter as well as high temperature in summer and autumn were unfavorable conditions. The Climate Vegetation Index(CVI) model was established by PLS using the maximum, minimum, and average temperatures;vapor pressure;rainfall;and air pressure as key meteorological factors. The Enhanced Vegetation Index(EVI) was well fitted by the CVI model, with the average coefficient of determination(r2) and root mean square error(RMSE) of 0.856 and 0.042, respectively. Finally, an assessment model of comprehensive meteorological conditions was built based on the interannual differences in CVI. The meteorological conditions in the study area in 2014 were successfully evaluated by combining the model and selected seasonal key meteorological factors. | Yanli CHEN Weihua MO Yonglin HUANG Jianfei MO Xiaohan HUANG Xiumei WEN | 2021 | Journal of Meteorological Research2021，35，1： | 3 |
| 3 | Precise Background Noise Power Estimate for Echo Cancellation显示文摘The reconstruction of background noise from an error signal of an adaptive filter is a key issue for developing Variable Step-Size Normalized Least Mean Square (VSS-NLMS) algorithm in the context of Echo Cancellation (EC). The core parameter in this algorithm is the Background Noise Power (BNP); in the estimation of BNP, the power difference between the desired signal and the filter output, statistically equaling to the error signal power, has been widely used in a rough manner. In this study, a precise BNP estimate is implemented by multiplying the rough estimate with a corrective factor, taking into consideration the fact that the error signal consists of background noise and misalignment noise. This corrective factor is obtained by subtracting half of the latest VSS value from 1 after analyzing the ratio of BNP to the misalignment noise. Based on the precise BNP estimate, the PVSS-NLMS algorithm suitable for the EC system is eventually proposed. In practice, the proposed algorithm exhibits a significant advantage of easier controllability application, as prior knowledge of the EC environment can be neglected. The simulation results support the preciseness of the BNP estimation and the effectiveness of the proposed algorithm. | Wen Haoxiang Lai Xiaohan Chen Longdao | 2012 | China Communications2012，9，11： | 2 |
| 4 | Numerical simulation and data assimilation of the water-energy cycle over semiarid northeastern China显示文摘The default fractional vegetation cover and terrain height were replaced by the estimated fractional vegetation cover, which was calculated by the Normalized Difference Vegetation Index(NDVI) of Earth Observing System Moderate-Resolution Imaging Spectroradiometer(EOS-MODIS) and the Digital Elevation Model of the Shuttle Radar Topography Mission(SRTM) system. The near-surface meteorological elements over northeastern China were assimilated into the three-dimensional variational data assimilation system(3DVar) module in the Weather Research and Forecasting(WRF) model. The structure and daily variations of air temperature, humidity, wind and energy fields over northeastern China were simulated using the WRF model. Four groups of numerical experiments were performed, and the simulation results were analyzed of latent heat flux, sensible heat flux, and their relationships with changes in the surface energy flux due to soil moisture and precipitation over different surfaces. The simulations were compared with observations of the stations Tongyu, Naiman, Jinzhou, and Miyun from June to August, 2009. The results showed that the WRF model achieves high-quality simulations of the diurnal characteristics of the surface layer temperature, wind direction, net radiation, sensible heat flux, and latent heat flux over semiarid northeastern China in the summer. The simulated near-surface temperature, relative humidity, and wind speed were improved in the data assimilation case(Case 2) compared with control case(Case 1). The simulated sensible heat fluxes and surface heat fluxes were improved by the land surface parameterization case(Case 3) and the combined case(Case 4). The simulated temporal variations in soil moisture over the northeastern arid areas agree well with observations in Case 4, but the simulated precipitation should be improved in the WRF model. This study could improve the land surface parameters by utilizing remote sensing data and could further improve atmospheric elements with a data assimilation system. This work provides an effective attempt at combining multi-source data with different spatial and temporal scales into numerical simulations. The assimilation datasets generated by this work can be applied to research on climate change and environmental monitoring of arid lands, as well as research on the formation and stability of climate over semiarid areas. | WEN XiaoHang LIAO XiaoHan YUAN WenPing YAN XiaoDong WEI ZhiGang LIU HuiZhi FENG JinMing LU ShiHua DONG WenJie | 2014 | Science China Earth Sciences2014，57，10： | 1 |
| 5 | An improved PNLMS algorithm for sparse impulse response identification显示文摘 | Wen Haoxiang Lai Xiaohan Chen Longdao | 2013 | Journal of ShangHaiJiaotong University (Science)2013，18，6： | 1 |
| 6 | Vibration Signal-Based Fault Diagnosis of Railway Point Machines via Double-Scale CNN显示文摘In the railway transportation industry,fault diagnosis of railway point machines(RPMs)is vital.Because operational vibration signals can reflect the condition of various faults in mechanical devices,vibration sensing and monitoring and more importantly,vibration signal-based fault diagnosis for RPMs have attracted the attention of scholars and engineers.Most vibration signal-based fault-diagnosis methods for RPMs rely on data collected using high-sampling-rate sensors and manual feature extraction,hence are costly and insufficiently robust.To overcome these shortcomings,we propose a double-scale wide first-layer kernel convolutional neural network(DS-WCNN)for RPMs fault diagnosis using inexpensive and low-sampling-rate vibration sensors.The proposed wide first-layer kernels,which extract features from vibration observations,are particularly suitable for low-sampling-rate signals.Meanwhile,the proposed double-scale structure improves accuracy and noise suppression by combining two types of timescale features.Sufficient experiments,including noise addition and comparison,were conducted to demonstrate the robustness and accuracy of the proposed algorithm. | CHEN Xiaohan HU Xiaoxi WEN Tao CAO Yuan | 2023 | Chinese Journal of Electronics2023，32，5： | 0 |
| 7 | Self-Assembled Porous-Reinforcement Microstructure-Based Flexible Triboelectric Patch for Remote Healthcare显示文摘Realizing real-time monitoring of physiological signals is vital for preventing and treating chronic diseases in elderly individuals. However,wearable sensors with low power consumption and high sensitivity to both weak physiological signals and large mechanical stimuli remain challenges.Here, a flexible triboelectric patch(FTEP) based on porous-reinforcement microstructures for remote health monitoring has been reported. The porousreinforcement microstructure is constructed by the self-assembly of silicone rubber adhering to the porous framework of the PU sponge. The mechanical properties of the FTEP can be regulated by the concentrations of silicone rubber dilution. For pressure sensing, its sensitivity can be effectively improved fivefold compared to the device with a solid dielectric layer, reaching 5.93 kPa^(-1) under a pressure range of 0–5 kPa. In addition, the FTEP has a wide detection range up to 50 kPa with a sensitivity of 0.21 kPa^(-1). The porous microstructure makes the FTEP ultra-sensitive to external pressure, and the reinforcements endow the device with a greater deformation limit in a wide detection range. Finally, a novel concept of the wearable Internet of Healthcare(Io H) system for real-time physiological signal monitoring has been proposed, which could provide real-time physiological information for ambulatory personalized healthcare monitoring. | Hao Lei Haifeng Ji Xiaohan Liu Bohan Lu Linjie Xie Eng Gee Lim Xin Tu Yina Liu Peixuan Zhang Chun Zhao Xuhui Sun Zhen Wen | 2023 | Nano-Micro Letters2023，15，7： | 0 |
| 8 | In-plane grain boundary induced defect state in hierarchical NiCo-LDH and effect on battery-type charge storage显示文摘Domain boundaries are regarded as the effective active sites for electrochemical energy storage materials due to defects enrichment therein.However,layered double hydroxides(LDHs)tend to grow into single crystalline nano sheets due to their unique two-dimentional(2D)lattice structure.Previously,much efforts were made on the designing hierarchical structure to provide more exposed electroactive sites as well as accelerate the mass transfer.Herein,we demonstrate a strategy to introduce low angle grain boundary(LAGB)in the flakes of Ni/Co layered double hydroxides(NiCo-LDHs).These defect-rich nano flakes were self-assembled into hydrangea-like spheres that further constructed hollow cage structure.Both the formation of hierarchical structure and grain boundaries are interpreted with the synergistic effect of Ni2+/Co2+ratio in an“etching-growth”process.The domain boundary defect also results in the preferential formation of oxygen vacancy(Vo).Additionally,density functional theory(DFT)calculation reveals that Co substitution is a critical factor for the formation of adjacent lattice defects,which contributes to the formation of domains boundary.The fabricated battery-type Faradaic NiCo-LDH-2 electrode material exhibits significantly enhanced specific capacitance of 899 C·g^(−1)at a current density of 1 A·g^(−1).NiCo-LDH-2//AC asymmetric capacitor shows a maximum energy density of 101.1 Wh·kg^(−1)at the power density of 1.5 kW·kg^(−1). | Jinjin Ban Xiaohan Wen Honghong Lei Guoqin Cao Xinhong Liu Chunyao Niu Guosheng Shao Junhua Hu | 2023 | Nano Research2023，16，4： | 0 |
| 9 | Gravity-Dependent Animacyy Perception in Zebrafish显示文摘Biological motion(BM),depicted by a handful of point lights attached to the major joints,conveys rich animacy information,which is significantly disrupted if BM is shown upside down.This well-known inversion effect in BM perception is conserved in terrestrial vertebrates and is presumably a manifestation of an evolutionarily endowed perceptual filter(i.e.,life motion detector)tuned to gravity-compatible BM.However,it remains unknown whether aquatic animals,living in a completely different environment from terrestrial animals,perceive BM in a gravity-dependent manner.Here,taking advantage of their typical shoaling behaviors,we used zebrafish as a model animal to examine the ability of teleosts to discriminate between upright(gravity-compatible)and inverted(gravity-incompatible)BM signals.We recorded their swimming trajectories and quantified their preference based on dwelling time and head orientation.The results obtained from three experiments consistently showed that zebrafish spent significantly more time swimming in proximity to and orienting towards the upright BM relative to the inverted BM or other gravity-incompatible point-light stimuli(i.e.,the non-BM).More intriguingly,when the recorded point-light video clips of fish were directly compared with those of human walkers and pigeons,we could identify a unique and consistent pattern of accelerating movements in the vertical(gravity)direction.These findings,to our knowledge,demonstrate for the first time the inversion effect in BM perception in simple aquatic vertebrates and suggest that the evolutionary origin of gravity-dependent BM processing may be traced back to ancient aquatic animals. | Xiaohan Ma Xiangyong Yuan Jiahuan Liu Li Shen Yiwen Yu Wen Zhou Zuxiang Liu Yi Jiang | 2023 | Research2023，，1： | 0 |
| 10 | Geographical distribution of Aspergillus flavus in peanut harvest period in China显示文摘In order to grasp the distribution of Aspergillus flavus in the soil of peanut production areas in China,A.flavus biomarkers were tested on 555 soil samples from 37 sampling points in 17 provinces,peanut fields in four agroecological zones(Southern area,Yangtze River Basin,Northern area,Northeast area).The results showed that(1)the cultivation amount of A.flavus per gram of soil in the Yangtze River Basin is 1.30 times that of the southern area,1.56 times that of the northern area,and 6.20 times that of the northeast area,with obvious regional characteristics.(2)In the Yangtze River basin,the change of longitude in the east-west direction has no direct impact on the cultivation amount of A.flavus per gram of soil.(3)In the east coast,the A.flavus cultivated per gram of soil increased first and then decreased with the increase of latitude from south to north.(4)A.flavus can be isolated in the soil samples above 1000 m.Field pollution is an important source of aflatoxin contamination in peanut.The study on the distribution of A.flavus in soil in China could provide theoretical support for the early warning and prevention and control measures of aflatoxin contamination in peanut. | Xiaohan Liu Jiayun Fu Mingbo Wen Haohua Gu Pingping Ji Xiaofeng Yue Xiaoqian Tang Meijuan Liang Yang Zhou Qi Zhang Peiwu Li | 2023 | Oil Crop Science2023，8，2： | 0 |
| 11 | Research progress on the relationship between m6A methylation of YTHDF1 gene in the striatum and stereotyped behavior显示文摘To the Editor: Stereotyped behavior refers to a series of behaviors with a high frequency and no obvious purpose and meaning. It also includes narrow interest and difficulty in accepting changes in things. In addition to autism spectrum disorder (ASD), stereotyped behavior also exists in various neurodevelopmental disorders, such as Tourette syndrome, Fragile X syndrome, Prader-Willi syndrome, obsessive-compulsive disorder, and many other diseases, which are considered to be related to dysfunction of the striatum. | Xiaohan Wen Xiaodong Liu Jingrong Wang Longsheng Huang Guihua Liu Haijun Wang Ping Ou | 2022 | Chinese Medical Journal2022，，9： | 0 |
| 12 | Bleaching with the Mixed Adsorbents of Activated Earth and Activated Alumina to Reduce Color and Oxidation Products of Anchovy Oil显示文摘Fish oil is a rich source of polyunsaturated fatty acids,and its refinement has drawn attention for years.An appropriate adsorbent can effectively remove the pigment impurities in the fish oil.This study evaluated the impact of different absorbents on the reduction of oxidation products and color of anchovy oil during the decolorization under high vacuum.Using the single factor design,four process parameters including adsorbents type,adsorbent amount,temperature and time were tested to determine the optimum decolorization parameter.The results showed the optimum decolorization conditions were that the fish oil was treated with 8%acti-vated alumina at 80℃for 40 min.In the central group experiment,the addition amounts of mixed absorbents(activated earth and activated alumina),including the mass ratio of adsorbent in oil(5%-11%,w/w)and the mass ratio of activated earth in total absor-bent(20%-80%,w/w)were optimized to remove the oxidation products.Under the optimum condition at 10.18%of adsorbent and 70%of activated earth,the total oxidation value(TOTOX value)showed the minimum with the 44.4%of removal rate.Eight metal elements were analyzed in decolorized oil using inductively coupled plasma mass spectrometry(ICP-MS).The removal rates of Zn and Pb were 94.12%and 55.35%,respectively.The decolorization process using mixed absorbents under appropriate condition can significantly reduce the oxidation products and pigments in fish oil,which will benefit the industrial production of fish oil. | WANG Xiaohan WEN Yunqi BI Shijie LI Zhaojie XUE Yong XUE Changhu JIANG Xiaoming | 2021 | Journal of Ocean University of China2021，20，5： | 0 |
| 13 | ON PAIRED PRIORITIZATIONS OF CRITERIA IN THE PERSPECTIVE OF DIAGRAPHS显示文摘It is not usually independent among criteria in multi-criteria decision making(MCDM),and various dependences of criteria greatly influence the results of decision making.If an exact decision is desired,we must make clear the role of the dependences of criteria.Prioritizations,a new kind of dependences of criteria proposed recently,imply that the importance weights of criteria with lower priority for an alternative rely on whether the alternative satisfies the decision maker under criteria with higher priority.It has been validated that there exist lots of relevant applications in our daily activities.However,most existing literatures focus on how to deal with the problems of MCDM with ordered prioritizations among criteria(a special form of prioritizations).The characteristics of prioritizations are not dug deep.This paper constructs a new form of prioritizations,called paired prioritizations,so as to reduce or even avoid imperfect rationality of decision makers hidden in the ordered prioritizations.We first represent binary paired prioritizations as a digraph,based on which we discover two kinds of imperfect rationality(inconsistency and incompleteness) produced in the period that the decision maker supplies the binary paired prioritizations.After the given paired prioritizations are consistent and complete,we develop an approach to transform the paired prioritizations to ordered prioritizations.The latter can be used to handle prioritized MCDM problems.Moreover,uncertainty,another kind of imperfect rationality,is considered when the decision maker provides the fuzzy paired prioritizations based on a set of linguistic labels.We construct a fuzzy digraph whose fuzzy relations are just the fuzzy paired prioritizations.The ordered prioritizations can then be derived with the aid of the fuzzy digraph.Two use cases are taken to show the process of transformations from binary/fuzzy paired prioritizations to ordered prioritizations. | Wenning Hao Xiaohan Yu Zeshui Xu Xiuli Qi | 2015 | Journal of Systems Science and Systems Engineering2015，24，4： | 0 |
| 14 | Electrokinetic transport of nanoparticles in functional group modified nanopores显示文摘Nanopore detection is a hot issue in current research.One of the challenges is how to slow down the transport velocity of nanoparticles in nanopores.In this paper,we propose a functional group modified nanopore.That means a polyelectrolyte brush layer is grafted on the surface of the nanopore to change the surface charge properties.The existing studies generally set the charge density of the brush layer to a fixed value.On the contrary,in this paper,we consider an essential property of the brush layer:the volume charge density is adjustable with pH.Thus,the charge property of the brush layer will change with the local H+concentration.Based on this,we established a mathematical model to study the transport of nanoparticles in polyelectrolyte brush layer modified nanopores.We found that pH can effectively adjust the charge density and even the polarity of the brush layer.A larger pH can reduce the transport velocity of nanoparticles and improve the blockade degree of ion current.The grafting density does not change the polarity of the brush charge.The larger the grafting density,the greater the charge density of the brush layer,and the blockade degree of ion current is also more obvious.The polyelectrolyte brush layer modified nanopores in this paper can effectively reduce the nanoparticle transport velocity and retain the essential ion current characteristics,such as ion current blockade and enhancement. | Teng Zhou Xiaohan He Juncheng Zhao Liuyong Shi Liping Wen | 2023 | Chinese Chemical Letters2023，34，6： | 0 |
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