检索结果-南通市图书馆

Chinese Medical Journal 2022年第9期135卷 1120-1122页

作者： Xiaohan Wen Xiaodong Liu Jingrong Wang Longsheng Huang Guihua Liu Haijun Wang Ping Ou Department of Child Healthcare Center Fujian Provincial Maternal and Children's HospitalAffiliated Hospital of Fujian Medical UniversityFuzhouFujian 350000China School of Clinical Medicine Fujian Medical UniversityFuzhouFujian 350004China Department of Maternal and Child Health School of Public HealthPeking UniversityBeijing 100191China

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.

关键词： striatum behavior diseases

A Harmonic Compensation Approach for Interlinking Voltage Source Converters in Hybrid AC-DC Microgrids with Low Switching Frequency

在线全文

学校读者我要写书评

暂无评论

CSEE Journal of Power and Energy Systems 2018年第1期4卷 39-48页

作者： Hao Tian Xiaohan Wen Yun Wei Li Department of Electrical and Computer Engineering University of AlbertaEdmontonABT6G 2V4Canada China Mobile Group Liaoning Co. Ltd.ShenyangChina

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.

关键词： Harmonic compensation hybrid AC-DC microgrid virtual impedance

Vibration Signal-Based Fault Diagnosis of Railway Point Machines via Double-Scale CNN

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Electronics 2023年第5期32卷 972-981页

作者： CHEN xiaohan HU Xiaoxi wen Tao CAO Yuan The School of Electronic and Information Engineering Beijing Jiaotong University The State Key Laboratory of Rail Traffic Control and Safety Beijing Jiaotong University The National Engineering Research Center of Rail Transportation Operation Control System Beijing Jiaotong University

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 signalbased 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 doublescale 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 lowsampling-rate signals. Meanwhile, the proposed doublescale 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.

关键词： Railway point machines Fault diagnosis Condition monitoring Vibration signals Convolutional neural networks

In-plane grain boundary induced defect state in hierarchical NiCo-LDH and effect on battery-type charge storage

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2023年第4期16卷 4908-4916页

作者： Jinjin Ban Xiaohan Wen Honghong Lei Guoqin Cao Xinhong Liu Chunyao Niu Guosheng Shao Junhua Hu School of Materials Science and Engineering Industrial Technology Research Institute of Resource and Materials of Henan ProvinceZhengzhou UniversityZhengzhou 450001China State Center for International Cooperation on Designer Low-carbon&Environmental Materials(CDLCEM) Zhengzhou University100 Kexue AvenueZhengzhou 450001China Henan Provincial Key Laboratory for Metal Fuel Battery Foguang Power Generation Equipment Co.Ltd50 Holly StreetZhengzhou 450000China International Laboratory for Quantum Functional Materials of Henan School of Physics and MicroelectronicsZhengzhou UniversityZhengzhou 450001China

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).

关键词： sacrificial template grain boundary oxygen vacancy(Vo) hierarchical structure

Electrokinetic transport of nanoparticles in functional group modified nanopores

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2023年第6期34卷 512-516页

作者： Teng Zhou xiaohan He Juncheng Zhao Liuyong Shi Liping wen Mechanical and Electrical Engineering College Hainan UniversityHaikou 570228China CAS Key Laboratory of Bio-inspired Materials and Interfacial Science Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijing 100190China

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.

关键词： Nanopore Polyelectrolyte brush layer Protonation and deprotonation reactions Velocity Ion current

Changes in Vegetation and Assessment of Meteorological Conditions in Ecologically Fragile Karst Areas

在线全文

学校读者我要写书评

暂无评论

Journal of Meteorological Research 2021年第1期35卷 172-183页

作者： Yanli CHEN Weihua MO Yonglin HUANG Jianfei MO xiaohan HUANG Xiumei wen Institute of Meteorological Sciences Guangxi Zhuang Autonomous Region(GZAR)Meteorological BureauNanning 530022 Hechi Meteorological Service GZAR Meteorological BureauHechi 547000 College of Geography and Planning Nanning Normal UniversityNanning 530001

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.

关键词： karst rocky area vegetation change ecologically fragile meteorological conditions

Self-Assembled Porous-Reinforcement Microstructure-Based Flexible Triboelectric Patch for Remote Healthcare

在线全文

学校读者我要写书评

暂无评论

Nano-Micro Letters 2023年第7期15卷 324-336页

作者： 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 Institute of Functional Nano and Soft Materials(FUNSOM) Joint International Research Laboratory of Carbon-Based Functional Materials and DevicesSoochow UniversitySuzhou 215123People’s Republic of China Department of Electrical and Electronic Engineering School of Advanced TechnologyXi’an Jiaotong-Liverpool UniversitySuzhou 215123People’s Republic of China Department of Applied Mathematics School of Mathematics and PhysicsXi’an Jiaotong-Liverpool UniversitySuzhou 215123People’s Republic of China Department of Electrical and Electronic Engineering University of LiverpoolLiverpool L693GJUK Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices Soochow UniversitySuzhou 215123JiangsuPeople’s Republic of China

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.

关键词： Pressure sensor Triboelectric nanogenerator Porous dielectric layer Physiological signals Internet of Healthcare

Precise Background Noise Power Estimate for Echo Cancellation

在线全文

学校读者我要写书评

暂无评论

China Communications 2012年第11期9卷 98-106页

作者： wen Haoxiang Lai xiaohan Chen Longdao College of Electrical Engineering Zhejiang University Hangzhou 310027 P. R. China

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.

关键词：功率估计背景噪声回声消除 NLMS算法自适应滤波器误差信号校正因子 BNP

在线全文

学校读者我要写书评

暂无评论

本溪市水资源压力变化趋势分析

黑龙江水利科技 2023年第7期51卷 84-86页

作者：温笑寒辽宁省本溪水文局辽宁本溪117000

文章通过计算水资源承载力和负载指数,评价分析本溪市2005—2020年的水资源压力变化趋势。结果表明:2005—2020年本溪市水资源负载指数总体呈上升趋势,水资源压力和承载力也表现出增大趋势;为有效缓解城市水资源压力,进一步增强水资源... 详细信息

文章通过计算水资源承载力和负载指数,评价分析本溪市2005—2020年的水资源压力变化趋势。结果表明:2005—2020年本溪市水资源负载指数总体呈上升趋势,水资源压力和承载力也表现出增大趋势;为有效缓解城市水资源压力,进一步增强水资源承载力,要加强水资源的科学有效管理,加快推进高水平先进节水技术的应用。

关键词：承载力负载指数水资源压力本溪市

基于水文学方法的南甸水文站近60年水沙演变成因分析

在线全文

学校读者我要写书评

暂无评论

水利技术监督 2022年第4期30卷 174-177页

作者：温笑寒辽宁省本溪水文局辽宁本溪117000

文章结合太子河南甸水文站建站以来近60年径流量和输沙量数据对其水沙演变特征进行分析,结合水文学方法对其变化成因进行定量分解。结果表明:近60年来南甸水文站年径流量和输沙量呈现明显递减变化,从20世纪70年代开始每10年水沙递减率... 详细信息

文章结合太子河南甸水文站建站以来近60年径流量和输沙量数据对其水沙演变特征进行分析,结合水文学方法对其变化成因进行定量分解。结果表明:近60年来南甸水文站年径流量和输沙量呈现明显递减变化,从20世纪70年代开始每10年水沙递减率均值分别为-9.5%和-11.5%。各年代际人类活动影响的比例均超过50%,为其水沙锐减变化的主因。

关键词：南甸水文站水沙变化影响成因成因分析