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RASI:the Robotic All-Sky narrowband Imager
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作者 Yuxin Xin Baoli Lun +6 位作者 Zejun Hu Yue Zhong Kai Ye Hongying Xu Yufeng Fan Bin Li Dehong Huang 《Astronomical Techniques and Instruments》 2025年第6期348-357,共10页
We report a new standalone Robotic All-Sky narrowband Imager(RASI)for auroral and airglow studies.RASI has new optics and an electromechanical system,low operation and installation costs,easy deployment and fully auto... We report a new standalone Robotic All-Sky narrowband Imager(RASI)for auroral and airglow studies.RASI has new optics and an electromechanical system,low operation and installation costs,easy deployment and fully automatic features.The new optics provide an all-sky field of view with excellent image quality and sensitivity.The new electromechanical system design offers a more compact size and the capability for outdoor independent deployment.We have also developed a fully automatic data acquisition software for RASI,which is based on the perception of solar altitude and the all-sky cloud cover.In conclusion,the RASI demonstrates significant advantages over the traditional all-sky narrowband imager,and it is highly suitable for the intensity measurements of large-scale auroras and airglow distributions. 展开更多
关键词 ROBOTIC All-sky imager AURORAS AIRGLOW Optical imaging
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Improving Image Quality of the Solar Disk Imager(SDI)of the LyαSolar Telescope(LST)Onboard the ASO-S Mission 被引量:1
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作者 Hui Liu Hui Li +11 位作者 Sizhong Zou Kaifan Ji Zhenyu Jin Jiahui Shan Jingwei Li Guanglu Shi Yu Huang Li Feng Jianchao Xue Qiao Li Dechao Song Ying Li 《Research in Astronomy and Astrophysics》 2025年第2期36-45,共10页
The in-flight calibration and performance of the Solar Disk Imager(SDI),which is a pivotal instrument of the LyαSolar Telescope onboard the Advanced Space-based Solar Observatory mission,suggested a much lower spatia... The in-flight calibration and performance of the Solar Disk Imager(SDI),which is a pivotal instrument of the LyαSolar Telescope onboard the Advanced Space-based Solar Observatory mission,suggested a much lower spatial resolution than expected.In this paper,we developed the SDI point-spread function(PSF)and Image Bivariate Optimization Algorithm(SPIBOA)to improve the quality of SDI images.The bivariate optimization method smartly combines deep learning with optical system modeling.Despite the lack of information about the real image taken by SDI and the optical system function,this algorithm effectively estimates the PSF of the SDI imaging system directly from a large sample of observational data.We use the estimated PSF to conduct deconvolution correction to observed SDI images,and the resulting images show that the spatial resolution after correction has increased by a factor of more than three with respect to the observed ones.Meanwhile,our method also significantly reduces the inherent noise in the observed SDI images.The SPIBOA has now been successfully integrated into the routine SDI data processing,providing important support for the scientific studies based on the data.The development and application of SPIBOA also paves new ways to identify astronomical telescope systems and enhance observational image quality.Some essential factors and precautions in applying the SPIBOA method are also discussed. 展开更多
关键词 techniques:image processing Sun:chromosphere Sun:flares methods:numerical
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Investigation on Physiological Status of Regional Vegetation Using Pushbroom Hyperspectral Imager Data 被引量:1
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作者 甘甫平 王润生 +1 位作者 马蔼乃 杨苏明 《Acta Botanica Sinica》 CSCD 2002年第8期983-989,共7页
To extract vegetation pigment concentration and physiological status has been studied in two test areas covered with swamp and flourish vegetation using pushbroom hyperspectral imager (PHI) data which flied in Septemb... To extract vegetation pigment concentration and physiological status has been studied in two test areas covered with swamp and flourish vegetation using pushbroom hyperspectral imager (PHI) data which flied in September of 2000 at Daxing'anling district of Heilongjiang Province, China. The ratio analysis of reflectance spectra (RARS) indices, which were put forward by Chappelle et al (1992), are chosen in this paper owing to their effect and simpleness against both comparison with various methods and techniques for exploration of pigment concentration and characteristics of PHI data. The correlation coefficients between RARS indices and pigment concentration of vegetation were up to 0.8. The new RARS indices modes are established in the two test areas using both PHI data and spectra of different vegetations measured in the field. The indices' parameter images of chlorophyll a (Chl a), chlorophyll b (Chl b) and carotenoids (Cars) of the test areas covered with swamp and flourish vegetation are acquired by the new RARS indices modes. Furthermore, the regional concentration of Chl a and Chl b are extracted and quantified using regression equations between RARS indices and pigment concentrations, which were built by Blackburn (1998). The results showed the physiological status and variety clearly, and are in good agreement with the distribution of vegetation in the field. 展开更多
关键词 pigment indices pigment concentration CHLOROPHYLL ratio analysis of reflectance spectra (RARS) indices pushbroom hyperspectral imager (PHI) Daxing'anling district
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Skin tone bias in online psoriasis imagery:Insights from an international study
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作者 Aman Sandhu Sanya Ailani +4 位作者 Smitesh Padte Priyal Mehta Neha Deo Salim Surani Rahul Kashyap 《World Journal of Clinical Cases》 2025年第36期6-12,共7页
BACKGROUND Psoriasis is often first recognized by patients through online image searches.However,search engine algorithms influenced by geographic location may still produce results that predominantly feature lighter ... BACKGROUND Psoriasis is often first recognized by patients through online image searches.However,search engine algorithms influenced by geographic location may still produce results that predominantly feature lighter skin tones,regardless of the region’s majority skin type.This underrepresentation may limit recognition and delay care for people of color.AIM To examine whether search algorithms tailor region-specific results in terms of skin color for psoriasis imagery.METHODS This observational study recruited 66 participants from 18 countries who conducted image searches for“psoriasis”across various web browsers.During the meeting,a Google form was posted to record observations,and participants reported the diversity of skin tones in the first three rows of search results using a reference image depicting Fitzpatrick types.RESULTS Results showed a global bias toward lighter skin tones,with 94%of participants identifying light skin predominance in the first row and minimal representation of medium or darker skin tones in subsequent results,verified via χ^(2) analysis.Participants who observed darker or mixed skin tones typically found them further down their results.CONCLUSION There remains a significant gap in global representation of psoriasis imagery.This paper deepens the current understanding of bias in online media and pushes for further exploration of more inclusive dermatologic imagery. 展开更多
关键词 PSORIASIS Internet Skin tone bias Image search Global
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On Translation Strategies for the Grass Imagery in Classical Chinese Poetry:A Cultural Semiotic Perspective
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作者 REN Rui LI Yutong SUN Yujingjing 《Sino-US English Teaching》 2025年第2期42-47,共6页
Grass constitutes a vital poetic imagery in classical Chinese poetry,embodying multifaceted symbolic connotations ranging from the tenacity of life to sentiments of separation and nostalgic longing.The translation of ... Grass constitutes a vital poetic imagery in classical Chinese poetry,embodying multifaceted symbolic connotations ranging from the tenacity of life to sentiments of separation and nostalgic longing.The translation of this botanical motif necessitates not merely lexical equivalence,but more importantly,the transmission of its profound cultural resonance and aesthetic essence.This study posits that effective rendition of grass imagery should adopt an integrative approach synthesizing the objectives of cultural translation with the intrinsic aesthetic characteristics of classical poetry.Through systematic analysis of the cultural semiotics embedded in grass symbolism,the research investigates practical translation techniques at lexical,syntactic,and stylistic dimensions.The findings aim to contribute to the theoretical framework of cultural image translation in Chinese poetic tradition while providing methodological references for cross-cultural interpretation of classical verse.By bridging cultural semiotics with translation praxis,this investigation seeks to advance the intercultural communication of Chinese poetic heritage through nuanced treatment of its botanical symbolism. 展开更多
关键词 classical Chinese poetry GRASS translation strategies cultural image
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Transformer-Based Fusion of Infrared and Visible Imagery for Smoke Recognition in Commercial Areas
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作者 Chongyang Wang Qiongyan Li +2 位作者 Shu Liu Pengle Cheng Ying Huang 《Computers, Materials & Continua》 2025年第9期5157-5176,共20页
With rapid urbanization,fires pose significant challenges in urban governance.Traditional fire detection methods often struggle to detect smoke in complex urban scenes due to environmental interferences and variations... With rapid urbanization,fires pose significant challenges in urban governance.Traditional fire detection methods often struggle to detect smoke in complex urban scenes due to environmental interferences and variations in viewing angles.This study proposes a novel multimodal smoke detection method that fuses infrared and visible imagery using a transformer-based deep learning model.By capturing both thermal and visual cues,our approach significantly enhances the accuracy and robustness of smoke detection in business parks scenes.We first established a dual-view dataset comprising infrared and visible light videos,implemented an innovative image feature fusion strategy,and designed a deep learning model based on the transformer architecture and attention mechanism for smoke classification.Experimental results demonstrate that our method outperforms existing methods,under the condition of multi-view input,it achieves an accuracy rate of 90.88%,precision rate of 98.38%,recall rate of 92.41%and false positive and false negative rates both below 5%,underlining the effectiveness of the proposed multimodal and multi-view fusion approach.The attention mechanism plays a crucial role in improving detection performance,particularly in identifying subtle smoke features. 展开更多
关键词 Multimodal image processing smoke recognition urban safety environmental monitoring
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Attention Driven YOLOv5 Network for Enhanced Landslide Detection Using Satellite Imagery of Complex Terrain
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作者 Naveen Chandra Himadri Vaidya +2 位作者 Suraj Sawant Shilpa Gite Biswajeet Pradhan 《Computer Modeling in Engineering & Sciences》 2025年第6期3351-3375,共25页
Landslide hazard detection is a prevalent problem in remote sensing studies,particularly with the technological advancement of computer vision.With the continuous and exceptional growth of the computational environmen... Landslide hazard detection is a prevalent problem in remote sensing studies,particularly with the technological advancement of computer vision.With the continuous and exceptional growth of the computational environment,the manual and partially automated procedure of landslide detection from remotely sensed images has shifted toward automatic methods with deep learning.Furthermore,attention models,driven by human visual procedures,have become vital in natural hazard-related studies.Hence,this paper proposes an enhanced YOLOv5(You Only Look Once version 5)network for improved satellite-based landslide detection,embedded with two popular attention modules:CBAM(Convolutional Block Attention Module)and ECA(Efficient Channel Attention).These attention mechanisms are incorporated into the backbone and neck of the YOLOv5 architecture,distinctly,and evaluated across three YOLOv5 variants:nano(n),small(s),and medium(m).The experiments use opensource satellite images from three distinct regions with complex terrain.The standard metrics,including F-score,precision,recall,and mean average precision(mAP),are computed for quantitative assessment.The YOLOv5n+CBAM demonstrates the most optimal results with an F-score of 77.2%,confirming its effectiveness.The suggested attention-driven architecture augments detection accuracy,supporting post-landslide event assessment and recovery. 展开更多
关键词 Attention mechanism convolutional neural networks LANDSLIDES remote sensing images YOLOv5
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Hyperspectral imagery quality assessment and band reconstruction using the prophet model
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作者 Ping Ma Jinchang Ren +2 位作者 Zhi Gao Yinhe Li Rongjun Chen 《CAAI Transactions on Intelligence Technology》 2025年第1期47-61,共15页
In Hyperspectral Imaging(HSI),the detrimental influence of noise and distortions on data quality is profound,which has severely affected the following-on analytics and decisionmaking such as land mapping.This study pr... In Hyperspectral Imaging(HSI),the detrimental influence of noise and distortions on data quality is profound,which has severely affected the following-on analytics and decisionmaking such as land mapping.This study presents an innovative framework for assessing HSI band quality and reconstructing the low-quality bands,based on the Prophet model.By introducing a comprehensive quality metric to start,the authors approach factors in both spatial and spectral characteristics across local and global scales.This metric effectively captures the intricate noise and distortions inherent in the HSI data.Subsequently,the authors employ the Prophet model to forecast information within the low-quality bands,leveraging insights from neighbouring high-quality bands.To validate the effectiveness of the authors’proposed model,extensive experiments on three publicly available uncorrected datasets are conducted.In a head-to-head comparison,the framework against six state-ofthe-art band reconstruction algorithms including three spectral methods,two spatialspectral methods and one deep learning method is benchmarked.The authors’experiments also delve into strategies for band selection based on quality metrics and the quality evaluation of the reconstructed bands.In addition,the authors assess the classification accuracy utilising these reconstructed bands.In various experiments,the results consistently affirm the efficacy of the authors’method in HSI quality assessment and band reconstruction.Notably,the authors’approach obviates the need for manually prefiltering of noisy bands.This comprehensive framework holds promise in addressing HSI data quality concerns whilst enhancing the overall utility of HSI. 展开更多
关键词 band reconstruction band quality hyperspectral image(HSI) prophet model
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Comparative Analysis of Deep Learning Models for Banana Plant Detection in UAV RGB and Grayscale Imagery
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作者 Ching-Lung Fan Yu-Jen Chung Shan-Min Yen 《Computers, Materials & Continua》 2025年第9期4627-4653,共27页
Efficient banana crop detection is crucial for precision agriculture;however,traditional remote sensing methods often lack the spatial resolution required for accurate identification.This study utilizes low-altitude U... Efficient banana crop detection is crucial for precision agriculture;however,traditional remote sensing methods often lack the spatial resolution required for accurate identification.This study utilizes low-altitude Unmanned Aerial Vehicle(UAV)images and deep learning-based object detection models to enhance banana plant detection.A comparative analysis of Faster Region-Based Convolutional Neural Network(Faster R-CNN),You Only Look Once Version 3(YOLOv3),Retina Network(RetinaNet),and Single Shot MultiBox Detector(SSD)was conducted to evaluate their effectiveness.Results show that RetinaNet achieved the highest detection accuracy,with a precision of 96.67%,a recall of 71.67%,and an F1 score of 81.33%.The study further highlights the impact of scale variation,occlusion,and vegetation density on detection performance.Unlike previous studies,this research systematically evaluates multi-scale object detection models for banana plant identification,offering insights into the advantages of UAV-based deep learning applications in agriculture.In addition,this study compares five evaluation metrics across the four detection models using both RGB and grayscale images.Specifically,RetinaNet exhibited the best overall performance with grayscale images,achieving the highest values across all five metrics.Compared to its performance with RGB images,these results represent a marked improvement,confirming the potential of grayscale preprocessing to enhance detection capability. 展开更多
关键词 Unmanned Aerial Vehicle image object detection deep learning banana crops
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Principle and Analysis of Novel Gate-Induced Noise in Pixel MOSFET of CMOS Imagers
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作者 金湘亮 陈杰 仇玉林 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2003年第9期921-926,共6页
A detailed principle and a rigorous analysis of a new noise,the gate-induced noise,in pixel MOSFET of CMOS imagers are provided.The gate-induced noise of the MOSFET is more notable in the strong reversion region than... A detailed principle and a rigorous analysis of a new noise,the gate-induced noise,in pixel MOSFET of CMOS imagers are provided.The gate-induced noise of the MOSFET is more notable in the strong reversion region than that in the subthreshold region when the applied gate voltage is low.However,the applied gate voltage being up to 3V,the gate-induced noise is more notable with the ω/ω T increasing when the MOSFET operates in the subthreshold region than that in the strong reversion region.Between the photocurrent I D and the root mean square value of the gated-induced noise,current i 2 d presents the relation of i 2 d∝I D in the saturation region of the strong reversion and approximately i 2 d∝I D in the subthreshold region.A deta iled and rigorous study of the gate-induced noise in the reset MOSFET for the p hotodiode APS and improved photodiode APS are provided.The improvement of logari thmic response APS is analyzed and the simulation results show that the gate-in duced noise can be reduced. 展开更多
关键词 gate-induced noise pixel MOSFET improved photodiode APS CMOS imagers
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Alpha Imager EP凝胶成像系统故障维修
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作者 刘海燕 常玉梅 《医疗卫生装备》 CAS 2012年第3期145-145,共1页
凝胶成像系统是分子生物学常用仪器,在医院临床检验和科研开发中发挥着重要的辅助作用。其主要是对电泳后的琼脂糖凝胶中的核酸在紫外灯管下的影像进行采集,并进行图像保存与定性分析。我院于2008年购进1台Al-pha Imager EP凝胶成像系统... 凝胶成像系统是分子生物学常用仪器,在医院临床检验和科研开发中发挥着重要的辅助作用。其主要是对电泳后的琼脂糖凝胶中的核酸在紫外灯管下的影像进行采集,并进行图像保存与定性分析。我院于2008年购进1台Al-pha Imager EP凝胶成像系统,此机器操作简便、图像清晰,并可以进行核酸半定量分析。 展开更多
关键词 凝胶成像系统 imager 故障维修 ALPHA EP 图像清晰 分子生物学 琼脂糖凝胶
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IMATION969 HQ Laser Imager故障检修
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作者 张兵 《医疗设备信息》 2002年第9期59-59,共1页
关键词 IMATION 969 HQ LASER imager 故障 检修
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柯达Ektascan 160 LASER IMAGER激光相机故障维修
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作者 李向东 王跃武 +1 位作者 肖雪莲 宋智勇 《医疗卫生装备》 CAS 2008年第8期132-132,共1页
设备卡片.当取出被卡的胶片后重新开机,机器无法启动,此时液晶屏可以闪亮,但相机连续出现“咔咔”声。
关键词 激光相机 imager 故障维修 柯达 液晶屏
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Sea ice thickness estimation in the Bohai Sea using geostationary ocean color imager data 被引量:9
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作者 LIU Wensong SHENG Hui ZHANG Xi 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2016年第7期105-112,共8页
A method to estimate the thickness of the sea ice of the Bohai Sea is proposed using geostationary ocean color imager (GOCI) data and then applied to the dynamic monitoring of the sea ice thickness in the Bohal Sea ... A method to estimate the thickness of the sea ice of the Bohai Sea is proposed using geostationary ocean color imager (GOCI) data and then applied to the dynamic monitoring of the sea ice thickness in the Bohal Sea during the winter of 2014 to 2015. First of all, a model is given between the GOCI shortwave broadband albedo and the reflectance of each band with high temporal resolution GOCI data. Then, the relationship model between the sea ice thickness and the GOCI shortwave broadband albedo is established and applied to the thickness extraction of the sea ice in the Bohai Sea. Finally, the sea ice thickness extraction method is tested by the results based on the MODIS data, thermodynamic empirical models (Lebedev and Zubov), and the in situ ice thickness data. The test results not only indicated that the sea ice thickness retrieval method based on the GOCI data was a good correlation (r2〉0.66) with the sea ice thickness retrieved by the MODIS and thermodynamic empirical models, but also that the RMS is only 6.82 cm different from the thickness of the sea ice based on the GOCI and in situ data. 展开更多
关键词 sea ice thickness geostationary ocean color imager Bohai Sea
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Aerial-BiSeNet:A real-time semantic segmentation network for high resolution aerial imagery 被引量:11
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作者 Fang WANG Xiaoyan LUO +1 位作者 Qixiong WANG Lu LI 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2021年第9期47-59,共13页
The aircraft system has recently gained its reputation as a reliable and efficient tool for sensing and parsing aerial scenes.However,accurate and fast semantic segmentation of highresolution aerial images for remote ... The aircraft system has recently gained its reputation as a reliable and efficient tool for sensing and parsing aerial scenes.However,accurate and fast semantic segmentation of highresolution aerial images for remote sensing applications is still facing three challenges:the requirements for limited processing resources and low-latency operations based on aerial platforms,the balance between high accuracy and real-time efficiency for model performance,and the confusing objects with large intra-class variations and small inter-class differences in high-resolution aerial images.To address these issues,a lightweight and dual-path deep convolutional architecture,namely Aerial Bilateral Segmentation Network(Aerial-Bi Se Net),is proposed to perform realtime segmentation on high-resolution aerial images with favorable accuracy.Specifically,inspired by the receptive field concept in human visual systems,Receptive Field Module(RFM)is proposed to encode rich multi-scale contextual information.Based on channel attention mechanism,two novel modules,called Feature Attention Module(FAM)and Channel Attention based Feature Fusion Module(CAFFM)respectively,are proposed to refine and combine features effectively to boost the model performance.Aerial-Bi Se Net is evaluated on the Potsdam and Vaihingen datasets,where leading performance is reported compared with other state-of-the-art models,in terms of both accuracy and efficiency. 展开更多
关键词 Aerial imagery Deap learning High resolution Image segmentation Real time
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Motor imagery training induces changes in brain neural networks in stroke patients 被引量:15
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作者 Fang Li Tong Zhang +3 位作者 Bing-Jie Li Wei Zhang Jun Zhao Lu-Ping Song 《Neural Regeneration Research》 SCIE CAS CSCD 2018年第10期1771-1781,共11页
Motor imagery is the mental representation of an action without overt movement or muscle activation. However, the effects of motor imagery on stroke-induced hand dysfunction and brain neural networks are still unknown... Motor imagery is the mental representation of an action without overt movement or muscle activation. However, the effects of motor imagery on stroke-induced hand dysfunction and brain neural networks are still unknown. We conducted a randomized controlled trial in the China Rehabilitation Research Center. Twenty stroke patients, including 13 males and 7 females, 32–51 years old, were recruited and randomly assigned to the traditional rehabilitation treatment group(PP group, n = 10) or the motor imagery training combined with traditional rehabilitation treatment group(MP group, n = 10). All patients received rehabilitation training once a day, 45 minutes per session, five times per week, for 4 consecutive weeks. In the MP group, motor imagery training was performed for 45 minutes after traditional rehabilitation training, daily. Action Research Arm Test and the Fugl-Meyer Assessment of the upper extremity were used to evaluate hand functions before and after treatment. Transcranial magnetic stimulation was used to analyze motor evoked potentials in the affected extremity. Diffusion tensor imaging was used to assess changes in brain neural networks. Compared with the PP group, the MP group showed better recovery of hand function, higher amplitude of the motor evoked potential in the abductor pollicis brevis, greater fractional anisotropy of the right dorsal pathway, and an increase in the fractional anisotropy of the bilateral dorsal pathway. Our findings indicate that 4 weeks of motor imagery training combined with traditional rehabilitation treatment improves hand function in stroke patients by enhancing the dorsal pathway. This trial has been registered with the Chinese Clinical Trial Registry(registration number: Chi CTR-OCH-12002238). 展开更多
关键词 nerve regeneration STROKE hand function motor imagery brain neural network motion evoked potential dorsal pathway ventral pathway diffusion tensor imaging neural regeneration
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High-resolution pixelated CdZnTe detector prototype system for solar hard X-ray imager 被引量:2
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作者 Shen Wang Jian-Hua Guo +1 位作者 Yan Zhang Wei Chen 《Nuclear Science and Techniques》 SCIE CAS CSCD 2019年第3期53-58,共6页
A multichannel low-noise electronic prototype system was designed for a pixelated CdZnTe detector. This system is the result of preliminary work on a solar hard X-ray imager, which is one of the three payloads for fut... A multichannel low-noise electronic prototype system was designed for a pixelated CdZnTe detector. This system is the result of preliminary work on a solar hard X-ray imager, which is one of the three payloads for future solar observations satellite-Advanced Space-based Solar Observatory(ASO-S). A new charge-sensitive amplifier application-specific integrated circuit, VATA450.3, with an on-chip analog-to-digital converter, is used to read out 8×8 anode pixel signals. Two CdZnTe detectors with a thickness of 2 mm and 5 mm were tested. The 2-mm-thick detector achieved energy resolution better than 5%(fullwidth at half-maximum, FWHM) at 59.5 keV, and the 5-mm-thick detector had better resolution than 1.2%(FWHM) at 662 keV. The design and test results of the prototype system are discussed in this paper. 展开更多
关键词 CDZNTE READOUT system SOLAR observation HARD X-ray imager
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Assessment and Assimilation of FY-3 Humidity Sounders and Imager in the UK Met Office Global Model 被引量:3
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作者 Fabien CARMINATI Brett CANDY +1 位作者 William BELL Nigel ATKINSON 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2018年第8期46-58,共13页
China's FengYnn 3 (FY-3) polar orbiting satellites axe set to become an important sonrce of observational data for nu- merical weather prediction (NWP), atmospheric reanalyses, and climate monitoring studies over... China's FengYnn 3 (FY-3) polar orbiting satellites axe set to become an important sonrce of observational data for nu- merical weather prediction (NWP), atmospheric reanalyses, and climate monitoring studies over the next two decades. As part of the Climate Science for Service Partnership China (CSSP China) prograln, FY-3B Microwave Humidity Sounder 1 (MWHS-1) and FY-3C MWHS-2 observations have been thoroughly assessed and prepared for operational assimilation. This represents the first time observations from China's polar orbiting satellites have been used in the UK's global NWP model. Since 2016, continuous data quality monitoring has shown occasional bias changes found to be correlated to changes in the energy supply scheme regulating the platform heating system and other transient anomalies. Nonetheless, MWHS-1 and MWHS-2 significantly contribute to the 24-h forecast error reduction by 0.3% and 0.6%, respectively, and the combination of both instruments is shown to improve the fit to the model background of independent sounders by up to 1%. The observations from the Microwave Radiation Imager (MWRI) also are a potentially significant source of benefits for NWP models, but a solar-dependent bias observed in the instrument half-orbits has prevented their assimilation. This paper presents the bases of a correction scheme developed at the Met Office for the purpose of a future assimilation of MWRI data. 展开更多
关键词 Microwave Humidity Sounder Microwave Radiation imager numerical weather prediction
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Assimilation of GPM Microwave Imager Radiance for Track Prediction of Typhoon Cases with the WRF Hybrid En3DVAR System 被引量:2
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作者 Dongmei XU Feifei SHEN +1 位作者 Jinzhong MIN Aiqing SHU 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2021年第6期983-993,共11页
The impact of assimilating radiance data from the advanced satellite sensor GMI(GPM microwave imager)for typhoon analyses and forecasts was investigated using both a three-dimensional variational(3DVAR)and a hybrid en... The impact of assimilating radiance data from the advanced satellite sensor GMI(GPM microwave imager)for typhoon analyses and forecasts was investigated using both a three-dimensional variational(3DVAR)and a hybrid ensemble-3DVAR method.The interface of assimilating the radiance for the sensor GMI was established in the Weather Research and Forecasting(WRF)model.The GMI radiance data are assimilated for Typhoon Matmo(2014),Typhoon Chan-hom(2015),Typhoon Meranti(2016),and Typhoon Mangkhut(2018)in the Pacific before their landing.The results show that after assimilating the GMI radiance data under clear sky condition with the 3DVAR method,the wind,temperature,and humidity fields are effectively adjusted,leading to improved forecast skills of the typhoon track with GMI radiance assimilation.The hybrid DA method is able to further adjust the location of the typhoon systematically.The improvement of the track forecast is even more obvious for later forecast periods.In addition,water vapor and hydrometeors are enhanced to some extent,especially with the hybrid method. 展开更多
关键词 WRF model GMI microwave imager data TYPHOON data assimilation
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Comparison of surface water extraction performances of different classic water indices using OLI and TM imageries in different situations 被引量:2
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作者 Ke ZHAI Xiaoqing WU +1 位作者 Yuanwei QIN Peipei DU 《Geo-Spatial Information Science》 SCIE EI CSCD 2015年第1期32-42,共11页
Recently,water extraction based on the indices method has been documented in many studies using various remote sensing data sources.Among them,Landsat satellites data have certain advantages in spatial resolution and ... Recently,water extraction based on the indices method has been documented in many studies using various remote sensing data sources.Among them,Landsat satellites data have certain advantages in spatial resolution and cost.After the successful launch of Landsat 8,the Operational Land Imager(OLI)data from the satellite are getting more and more attention because of its new improvements.In this study,we used the OLI imagery data source to study the water extraction performance based on the Normalized Difference Vegetation Index,Normalized Difference Water Index,Modified Normalized Water Index(MNDWI),and Automated Water Extraction Index(AWEI)and compared the results with the Thematic Mapper(TM)imagery data.Two test sites in Tianjin City of north China were selected as the study area to verify the applicability of OLI data and demonstrate its advantages over TM data.We found that the results of surface water extraction based on OLI data are slightly better than that based on TM in the two test sites,especially in the city site.The AWEI and MNDWI indices performs better than the other two indices,and the thresholds of water indices show more stability when using the OLI data.So,it is suitable to combine OLI imagery with other Landsat sensor data to study water changes for long periods of time. 展开更多
关键词 water extraction operational land imager(OLI)data threshold stability water indices
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