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Aquaporin-4-IgG-seropositive neuromyelitis optica spectrum disorders:progress of experimental models based on disease pathogenesis
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作者 Li Xu Huiming Xu Changyong Tang 《Neural Regeneration Research》 SCIE CAS 2025年第2期354-365,共12页
Neuromyelitis optica spectrum disorders are neuroinflammatory demyelinating disorders that lead to permanent visual loss and motor dysfunction.To date,no effective treatment exists as the exact causative mechanism rem... Neuromyelitis optica spectrum disorders are neuroinflammatory demyelinating disorders that lead to permanent visual loss and motor dysfunction.To date,no effective treatment exists as the exact causative mechanism remains unknown.Therefore,experimental models of neuromyelitis optica spectrum disorders are essential for exploring its pathogenesis and in screening for therapeutic targets.Since most patients with neuromyelitis optica spectrum disorders are seropositive for IgG autoantibodies against aquaporin-4,which is highly expressed on the membrane of astrocyte endfeet,most current experimental models are based on aquaporin-4-IgG that initially targets astrocytes.These experimental models have successfully simulated many pathological features of neuromyelitis optica spectrum disorders,such as aquaporin-4 loss,astrocytopathy,granulocyte and macrophage infiltration,complement activation,demyelination,and neuronal loss;however,they do not fully capture the pathological process of human neuromyelitis optica spectrum disorders.In this review,we summarize the currently known pathogenic mechanisms and the development of associated experimental models in vitro,ex vivo,and in vivo for neuromyelitis optica spectrum disorders,suggest potential pathogenic mechanisms for further investigation,and provide guidance on experimental model choices.In addition,this review summarizes the latest information on pathologies and therapies for neuromyelitis optica spectrum disorders based on experimental models of aquaporin-4-IgG-seropositive neuromyelitis optica spectrum disorders,offering further therapeutic targets and a theoretical basis for clinical trials. 展开更多
关键词 AQUAPORIN-4 experimental model neuromyelitis optica spectrum disorder PATHOGENESIS
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Advances in the treatment of autism spectrum disorder:Wharton jelly mesenchymal stem cell transplantation
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作者 Serdar Kabatas ErdinçCivelek +3 位作者 Eyüp Can Savrunlu Umut Karaaslan Özlem Yıldız Erdal Karaöz 《World Journal of Methodology》 2025年第1期72-79,共8页
BACKGROUND Autism spectrum disorder(ASD)is a complex neurodevelopmental disorder with multifaceted origins.In recent studies,neuroinflammation and immune dysregulation have come to the forefront in its pathogenesis.Th... BACKGROUND Autism spectrum disorder(ASD)is a complex neurodevelopmental disorder with multifaceted origins.In recent studies,neuroinflammation and immune dysregulation have come to the forefront in its pathogenesis.There are studies suggesting that stem cell therapy may be effective in the treatment of ASD.AIM To evolve the landscape of ASD treatment,focusing on the potential benefits and safety of stem cell transplantation.METHODS A detailed case report is presented,displaying the positive outcomes observed in a child who underwent intrathecal and intravenous Wharton’s jelly-derived mesenchymal stem cells(WJ-MSCs)transplantation combined with neurorehabilitation.RESULTS The study demonstrates a significant improvement in the child’s functional outcomes(Childhood Autism Rating Scale,Denver 2 Developmental Screening Test),especially in language and gross motor skills.No serious side effects were encountered during the 2-year follow-up.CONCLUSION The findings support the safety and effectiveness of WJ-MSC transplantation in managing ASD. 展开更多
关键词 Autism spectrum disorder NEUROREHABILITATION Stem cell transplantation Wharton jelly mesenchymal stem cells INFLAMMATION
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Autologous cord blood vs individualized supplements in autistic spectrum disorder:CORDUS study results
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作者 Felician A Stancioiu Raluca Bogdan +1 位作者 Bogdan Ivanescu Radu Dumitrescu 《World Journal of Clinical Pediatrics》 2025年第1期101-112,共12页
BACKGROUND Cellular therapies have started an important new therapeutic direction in autistic spectrum disorder(ASD),and the ample diversity of ASD pathophysiology and the different types of cell therapies prompt an e... BACKGROUND Cellular therapies have started an important new therapeutic direction in autistic spectrum disorder(ASD),and the ample diversity of ASD pathophysiology and the different types of cell therapies prompt an equally ample effort to employ clinical studies for studying the ASD causes and cell therapies.Stem cells have yielded so far mixed results in clinical trials,and at patient level the results varied from impressive to no improvement.In this context we have administered autologous cord blood(ACB)and a non-placebo,material intervention repre-sented by an individualized combination of supplements(ICS)to ASD children.METHODS CORDUS clinical study is a crossover study in which both oral ICS and intravenous ACB were sequentially administered to 56 children;ACB was infused as an inpatient procedure.Treatment efficacy was evaluated pre-treatment and post-treatment at 6 months by an independent psychotherapist with Autism Treatment Evaluation Checklist,Quantitative Checklist for Autism in Toddlers and a 16-item comparative table score,after interviewing the children’s parents and therapists.Before and after each intervention participants had a set of blood tests including inflammatory,metabolic and oxidative markers,and the neuronal specific enolase.RESULTS No serious adverse reactions were noted during and after cord blood or supplement administration.ACB improved evaluation scores in 78%of children with age 3–7-years(n=28),but was much less effective in kids older than 8 years or with body weight of more than 35 kg(n=28;only 11%of children improved scores).ICS yielded better results than ACB in 5 cases out of 28,while in 23 kids ACB brought more improvement than ICS(P<0.05);high initial levels of inflammation and ferritin were associated with no improvement.Ample individual differences were noted in children's progress,and statistically significant improvements were seen after ACB on areas such as verbalization and social interaction,but not on irritability or aggressive behavior.CONCLUSION ACB has superior efficacy to ICS in ASD;high inflammation,ferritin,age and body weight predict less improvement;more clinical studies are needed for studying ACB efficacy in ASD. 展开更多
关键词 Autistic spectrum disorder Cord blood Stem cells NEUROINFLAMMATION Autologous stem cell treatment Neuronal specific enolase
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Autism spectrum disorder:difficulties in diagnosis and microRNA biomarkers
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作者 Bridget Martinez Philip V.Peplow 《Neural Regeneration Research》 SCIE CAS 2025年第10期2776-2786,共11页
We performed a PubMed search for microRNAs in autism spectrum disorder that could serve as diagnostic biomarkers in patients and selected 17 articles published from January 2008 to December 2023,of which 4 studies wer... We performed a PubMed search for microRNAs in autism spectrum disorder that could serve as diagnostic biomarkers in patients and selected 17 articles published from January 2008 to December 2023,of which 4 studies were performed with whole blood,4 with blood plasma,5 with blood serum,1 with serum neural cell adhesion molecule L1-captured extracellular vesicles,1 with blood cells,and 2 with peripheral blood mononuclear cells.Most of the studies involved children and the study cohorts were largely males.Many of the studies had performed microRNA sequencing or quantitative polymerase chain reaction assays to measure microRNA expression.Only five studies had used real-time polymerase chain reaction assay to validate microRNA expression in autism spectrum disorder subjects compared to controls.The microRNAs that were validated in these studies may be considered as potential candidate biomarkers for autism spectrum disorder and include miR-500a-5p,-197-5p,-424-5p,-664a-3p,-365a-3p,-619-5p,-664a-3p,-3135a,-328-3p,and-500a-5p in blood plasma and miR-151a-3p,-181b-5p,-320a,-328,-433,-489,-572,-663a,-101-3p,-106b-5p,-19b-3p,-195-5p,and-130a-3p in blood serum of children,and miR-15b-5p and-6126 in whole blood of adults.Several important limitations were identified in the studies reviewed,and need to be taken into account in future studies.Further studies are warranted with children and adults having different levels of autism spectrum disorder severity and consideration should be given to using animal models of autism spectrum disorder to investigate the effects of suppressing or overexpressing specific microRNAs as a novel therapy. 展开更多
关键词 autism spectrum disorder BIOMARKER blood cells blood plasma blood serum DIAGNOSIS MICRORNA peripheral blood mononuclear cells serum neural cell adhesion molecule L1-captured extracellular vesicles whole blood
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Identification of the unknown shielding parameters with gammaray spectrum using a derivative-free inverse radiation transport model 被引量:3
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作者 Ying Chen Lian-Ping Zhang +4 位作者 Sa Xiao Lun-Qiang Wu Shan-Li Yang Bing-Yuan Xia Jian-Min Hu 《Nuclear Science and Techniques》 SCIE CAS CSCD 2018年第5期75-81,共7页
Identifying the unknown geometric and material information of a multi-shield object by analyzing the radiation signature measurements is always an important problem in national and global security. In order to identif... Identifying the unknown geometric and material information of a multi-shield object by analyzing the radiation signature measurements is always an important problem in national and global security. In order to identify the unknown shielding layer thicknesses of a source/shield system with gamma-ray spectra, we have developed a derivative-free inverse radiation transport model based on a differential evolution algorithm with global and local neighbourhoods(IRT-DEGL). In the present paper, the IRT-DEGL model is further extended for estimating the unknown thicknesses with random initial guesses and material mass densities of multi-shielding layers as well as their combinations. Using the detected gamma-ray spectra,the illustration of inverse studies is implemented and the main influence factors for inverse results are also analyzed. 展开更多
关键词 INVERSE problem DERIVATIVE-FREE INVERSE RADIATION transport model GAMMA-ray spectrum Multishielding layers
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Design of Time-Resolved Shifted Dual Transmission Grating Spectrometer for the X-Ray Spectrum Diagnostics 被引量:1
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作者 王保清 易涛 +6 位作者 王传珂 朱效立 李廷帅 李晋 刘慎业 江少恩 丁永坤 《Plasma Science and Technology》 SCIE EI CAS CSCD 2016年第7期781-785,共5页
A new time-resolved shifted dual transmission grating spectrometer (SDTGS) is designed and fabricated in this work. This SDTGS uses a new shifted dual transmission grating (SDTG) as its dispersive component, which... A new time-resolved shifted dual transmission grating spectrometer (SDTGS) is designed and fabricated in this work. This SDTGS uses a new shifted dual transmission grating (SDTG) as its dispersive component, which has two sub transmission gratings with different line densities, of 2000 lines/mm and 5000 lines/mm. The axes of the two sub transmission gratings in SDTG are horizontally and vertically shifted a certain distance to measure a broad range of 0.1-5 keV time-resolved X-ray spectra. The SDTG has been calibrated with a soft X-ray beam of the synchrotron radiation facility and its diffraction efficiency is also measured. The designed SDTGS can take full use of the space on a record panel and improve the precision for measuring spatial and temporal spectrum simultaneously. It will be a promising application for accurate diagnosis of the soft X-ray spectrum in inertial confinement fusion. 展开更多
关键词 shifted dual transmission grating spectrometer GRATING X-ray spectra diag-nosis of the soft X-ray spectrum
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Spectrum evolution of Rayleigh backscattering in one‐dimensional waveguide 被引量:2
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作者 Fuhui Li Tianyi Lan +3 位作者 Ligang Huang Iroegbu Paul Ikechukwu Wuming Liu Tao Zhu 《Opto-Electronic Advances》 2019年第8期2-8,共7页
Despite the tremendous awareness of Rayleigh scattering characteristics and its considerable research interest for numerous fields,no report has been documented on the dynamic characteristics of spectrum evolution(SpE... Despite the tremendous awareness of Rayleigh scattering characteristics and its considerable research interest for numerous fields,no report has been documented on the dynamic characteristics of spectrum evolution(SpE)and physical law for Rayleigh scattering from a micro perspective.Herein,the dynamic characteristics of the SpE of Rayleigh scattering in a one-dimensional waveguide(ODW)is investigated based on the quantum theory and a SpE-model of Rayleigh backscattering(RBS)source is established.By means of simulation,the evolution law which represents the dynamic process of the spectrum linewidth at a state of continuous scattering is revealed,which is consistent with our previous experimental observation.Moreover,an approximate theoretical prediction of the existing relationship between the spectrum linewidth of RBS source and the transmission length in ODW is proposed,which theoretically provides the feasibility of constructing functional devices suitable to ascertain laser linewidth compression.The designed experimental scheme can be implemented provided the assumptions are fulfilled.In addition,a theoretical model of the micro-cavity structure to realize the deep compression of laser linewidth is proposed. 展开更多
关键词 scattering rayLEIGH spectrum EVOLUTION LINEWIDTH functional device
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Ankle Phenomenon in the Cosmic Ray Energy Spectrum 被引量:2
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作者 Yukio Tomozawa 《Journal of Modern Physics》 2013年第3期385-389,共5页
The author has suggested that the knee phenomenon in the cosmic ray energy spectrum at 3 PeV can be explained as a split between a radiation-dominated expansion and a matter-dominated expansion of an expanding heat ba... The author has suggested that the knee phenomenon in the cosmic ray energy spectrum at 3 PeV can be explained as a split between a radiation-dominated expansion and a matter-dominated expansion of an expanding heat bath. The model proposed in 1985, in fact, predicted that high energy cosmic rays are emitted from AGN, massive black holes, in agreement with recent data from the Pierre Auger Observatory. Similarly, the ankle phenomenon at 3 EeV is shown to be explained by a split between inflational expansion and ordinary material expansion of the expanding heat bath, not unlike that in the expansion of the universe. All the spectral indicies in the respective regions of the energy spectra agree with the theoretical calculation from the respective expansion rates. It is shown that the ankle energy is approximately equal to the threshold energy of cosmic ray production of an electron positron pair on the cmb photon. 展开更多
关键词 COSMIC rayS COSMOLOGY Knee Energy INFLATION
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Rayleigh Quotient Based Interference Alignment Spectrum Sharing in MIMO Cognitive Radio Networks 被引量:1
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作者 RONG MEI 《China Communications》 SCIE CSCD 2015年第6期96-105,共10页
An interference alignment(IA)spectrum sharing method based on Rayleigh quotient is proposed for distributed multi-user multi-antenna cognitive radio(CR) networks.The interference from cognitive users(CUs)to the primar... An interference alignment(IA)spectrum sharing method based on Rayleigh quotient is proposed for distributed multi-user multi-antenna cognitive radio(CR) networks.The interference from cognitive users(CUs)to the primary(PR) system is constrained through the Rayleigh quotients of channel matrices to deal with the absence of PR users(PUs) in the IA process.As a result,the IA scheme can be applied in CR networks without harmful interference to PUs.Compared with existing IA based spectrum sharing methods,the proposed method is more general because of breaking the restriction that CUs can only transmit on the idle sub-channels of the PR system.Moreover,in comparison to other four spectrum sharing methods applicable in general scene,the proposed method leads to improved performance of achievable sum rate of the CR system as well as guarantees the transmission of PUs. 展开更多
关键词 cognitive radio spectrum sharing rayleigh quotient interference alignment MIMO
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On the intrinsic shape of the gamma-ray spectrum for Fermi blazars 被引量:1
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作者 Shi-Ju Kang Qingwen Wu +8 位作者 Yong-Gang Zheng Yue Yin Jia-Li Song Hang Zou Jian-Chao Feng Ai-Jun Dong Zhong-Zu Wu Zhi-Bin Zhang Lin-Hui Wu 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2018年第5期93-98,共6页
The curvature of the γ-ray spectrum in blazars may reflect the intrinsic distribution of emitting electrons, which will further give some information on the possible acceleration and cooling processes in the emitting... The curvature of the γ-ray spectrum in blazars may reflect the intrinsic distribution of emitting electrons, which will further give some information on the possible acceleration and cooling processes in the emitting region. The γ-ray spectra of Fermi blazars are normally fitted either by a single power-law(PL) or a log-normal(call Logarithmic Parabola, LP) form. The possible reason for this difference is not clear. We statistically explore this issue based on the different observational properties of 1419 Fermi blazars in the 3 LAC Clean Sample. We find that the γ-ray flux(100 Me V–100 Ge V) and variability index follow bimodal distributions for PL and LP blazars, where the γ-ray flux and variability index show a positive correlation. However, the distributions of γ-ray luminosity and redshift follow a unimodal distribution. Our results suggest that the bimodal distribution of γ-ray fluxes for LP and PL blazars may not be intrinsic and all blazars may have an intrinsically curved γ-ray spectrum, and the PL spectrum is just caused by the fitting effect due to less photons. 展开更多
关键词 GALAXIES active - galaxies jets - gamma rays galaxies - galaxies STATISTICS
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A novel approach for feature extraction from a gamma‑ray energy spectrum based on image descriptor transferring for radionuclide identification 被引量:1
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作者 Hao‑Lin Liu Hai‑Bo Ji +3 位作者 Jiang‑Mei Zhang Cao‑Lin Zhang Jing Lu Xing‑Hua Feng 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2022年第12期88-104,共17页
This study proposes a novel feature extraction approach for radionuclide identification to increase the precision of identification of the gamma-ray energy spectrum set.For easier utilization of the information contai... This study proposes a novel feature extraction approach for radionuclide identification to increase the precision of identification of the gamma-ray energy spectrum set.For easier utilization of the information contained in the spectra,the vectors of the gamma-ray energy spectra from Euclidean space,which are fingerprints of the different types of radionuclides,were mapped to matrices in the Banach space.Subsequently,to make the spectra in matrix form easier to apply to image-based deep learning frameworks,the matrices of the gamma-ray energy spectra were mapped to images in the RGB color space.A deep convolutional neural network(DCNN)model was constructed and trained on the ImageNet dataset.The mapped gamma-ray energy spectrum images were applied as inputs to the DCNN model,and the corresponding outputs of the convolution layers and fully connected layers were transferred as descriptors of the images to construct a new classification model for radionuclide identification.The transferred image descriptors consist of global and local features,where the activation vectors of fully connected layers are global features,and activations from convolution layers are local features.A series of comparative experiments between the transferred image descriptors,peak information,features extracted by the histogram of the oriented gradients(HOG),and scale-invariant feature transform(SIFT)using both synthetic and measured data were applied to 11 classical classifiers.The results demonstrate that although the gamma-ray energy spectrum images are completely unfamiliar to the DCNN model and have not been used in the pre-training process,the transferred image descriptors achieved good classification results.The global features have strong semantic information,which achieves an average accuracy of 92.76%and 94.86%on the synthetic dataset and measured dataset,respectively.The results of the statistical comparison of features demonstrate that the proposed approach outperforms the peak-searching-based method,HOG,and SIFT on the synthetic and measured datasets. 展开更多
关键词 Radionuclide identification Feature extraction Transfer learning Gamma energy spectrum analysis Image descriptor
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SENSORING DROPLET SPRAY TRANSFER IN MIG WELDING BASED ON ARC SPECTRUM SIGNAL
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作者 Liu Gang,Li Junyue,Li Huan,Fan Ronghuan (School of Material Engineering, Tianjin University) 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2001年第3期237-242,共6页
The method to detect droplet transfer by means of arc spectrum, while the experiment sets, testing principle and data processing procedure,are presented. The experiment and analysis results show that arc spectrum si... The method to detect droplet transfer by means of arc spectrum, while the experiment sets, testing principle and data processing procedure,are presented. The experiment and analysis results show that arc spectrum signal can be utilized to detect and measure the transfer procedure, the transfer modes and the transfer parameters. The arc spectrum signal enjoys excellent quality with high signal amplitude. Each transfer mode has its specific typical signal mode, and the pulse outline corresponds to an integrated transferring procedure of one droplet. All these features of arc spectrum signal can be easily applied hi the control of transfer procedure,the identification and stabilization of transfer mode and the measurement of transfer parameters. 展开更多
关键词 MIG welding Arc spectrum Signal feature Droplet transfer DETECTION
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Space-Resolved Spectrum Diagnose by Soft X-Ray Transmission Grating Spectrometer
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作者 尚万里 赵阳 +2 位作者 熊刚 杨家敏 朱托 《Plasma Science and Technology》 SCIE EI CAS CSCD 2011年第1期36-39,共4页
A space-resolving transmission grating spectrometer is established on the "Shenguang-III" prototype laser facility and an iterative procedure for unfolding the X-ray spectrum with spatial resolution is described. Th... A space-resolving transmission grating spectrometer is established on the "Shenguang-III" prototype laser facility and an iterative procedure for unfolding the X-ray spectrum with spatial resolution is described. The diagnostics is applied to measure the X-ray spectrum from laser-entered gold target and the typical space-resolved spectrum is provided. The relative standard uncertainty of the X-ray spectrum from the laser-generated plasma is also determined. 展开更多
关键词 transmission grating spectrometer numerical simulation spectrum diagnose
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Study of Cosmic-Ray Energy Spectrum during Solar Weather Disturbance
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作者 Turlan Sadykov Olga Novolodskaya Emar Tautaev Natalya Zastrozhnova Mark Zhunusbekov 《Journal of Physical Science and Application》 2014年第7期450-453,共4页
The purpose of this experiment is to investigate the dynamics of the intensity of cosmic ray flows and to obtain the energy spectrum of solar cosmic rays according to the data of measurements of neutron monitors at th... The purpose of this experiment is to investigate the dynamics of the intensity of cosmic ray flows and to obtain the energy spectrum of solar cosmic rays according to the data of measurements of neutron monitors at the height of 3,340, 1,700, 800 meters above the sea level. Also the estimation of energy spectrum of cosmic rays flows during the disturbances of solar activity (GLE) was made. 展开更多
关键词 Cosmic rays energy spectrum neutron monitors
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SPATIAL SPECTRUM ESTIMATION OF COHERENT SOURCES IMPINGING ON NONUNIFORM ARRAYS
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作者 路鸣 保铮 《Journal of Electronics(China)》 1991年第3期193-205,共13页
The problem of bearing estimation of coherent signal impingiog on an array ofarbitrary geometry is studied.Both approaches are developed,the first one synthesizes theobserved array data into the outputs of a linear un... The problem of bearing estimation of coherent signal impingiog on an array ofarbitrary geometry is studied.Both approaches are developed,the first one synthesizes theobserved array data into the outputs of a linear uniform array and then processes them viaconventional techniques such as spatial smoothing etc.The second approach is based on theinvariant subspace rotation operation which is equivalent to the translational displacement ofthe artay,linearly independent signal vectors are obtained thereby to span perfectly the signalsubspace.As compared with the conventional processing techniques,the approach based oninvariant subspace rotation does not lead to an effective decrease in aperture size and thereforea decrease in resolution capability.The computer simulations are conducted to demonstrate theeffectiveness of the presented approaches. 展开更多
关键词 Array signal processing Spatial spectrum estimation Direction finding COHERENT SIGNALS
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Exploring impedance spectrum for lithium-ion batteries diagnosis and prognosis:A comprehensive review 被引量:2
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作者 Xinghao Du Jinhao Meng +2 位作者 Yassine Amirat Fei Gao Mohamed Benbouzid 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第8期464-483,I0010,共21页
Lithium-ion batteries have extensive usage in various energy storage needs,owing to their notable benefits of high energy density and long lifespan.The monitoring of battery states and failure identification are indis... Lithium-ion batteries have extensive usage in various energy storage needs,owing to their notable benefits of high energy density and long lifespan.The monitoring of battery states and failure identification are indispensable for guaranteeing the secure and optimal functionality of the batteries.The impedance spectrum has garnered growing interest due to its ability to provide a valuable understanding of material characteristics and electrochemical processes.To inspire further progress in the investigation and application of the battery impedance spectrum,this paper provides a comprehensive review of the determination and utilization of the impedance spectrum.The sources of impedance inaccuracies are systematically analyzed in terms of frequency response characteristics.The applicability of utilizing diverse impedance features for the diagnosis and prognosis of batteries is further elaborated.Finally,challenges and prospects for future research are discussed. 展开更多
关键词 Lithium-ion battery Impedance spectrum Temperature monitoring Failure diagnosis Health prognosis
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Statistical properties of the photoelectron energy spectrum generated by an intense laser pulse and a continuous X-ray
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作者 葛愉成 葛湘洁 何海萍 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第11期325-331,共7页
This study shows that the photoelectron energy spectrum generated by an intense laser pulse in the presence of a continuous X-ray has interesting and useful statistical properties. The total photoionization production... This study shows that the photoelectron energy spectrum generated by an intense laser pulse in the presence of a continuous X-ray has interesting and useful statistical properties. The total photoionization production is linearly propor- tional to the time duration of the laser pulse and the square of the beam size. The spectral double energy-integration is an intrinsic value of the laser-assisted X-ray photoionization, which linearly depends on the laser intensity and which quantita- tively reflects the strengths of the laser-field modulation and the quantum interference between photoelectrons. The spectral energy width also linearly depends on the laser intensity. These linear relationships suggest new methods for the in-situ measurement of laser intensity and pulse duration with high precision. 展开更多
关键词 laser intensity pulse duration X-ray-boosted photoionization statistical properties of photoelec-tron energy spectrum
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Uphill or downhill?Cropland use change and its drivers from the perspective of slope spectrum 被引量:2
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作者 PAN Sipei LIANG Jiale +1 位作者 CHEN Wanxu PENG Yelin 《Journal of Mountain Science》 SCIE CSCD 2024年第2期484-499,共16页
The continuous decrease of low-slope cropland resources caused by construction land crowding poses huge threat to regional sustainable development and food security.Slope spectrum analysis of topographic and geomorphi... The continuous decrease of low-slope cropland resources caused by construction land crowding poses huge threat to regional sustainable development and food security.Slope spectrum analysis of topographic and geomorphic features is considered as a digital terrain analysis method which reflects the macro-topographic features by using micro-topographic factors.However,pieces of studies have extended the concept of slope spectrum in the field of geoscience to construction land to explore its expansion law,while research on the slope trend of cropland from that perspective remains rare.To address the gap,in virtue of spatial analysis and geographically weighted regression(GWR)model,the cropland use change in the Yangtze River Basin(YRB)from 2000 to 2020 was analyzed and the driving factors were explored from the perspective of slope spectrum.Results showed that the slope spectrum curves of cropland area-frequency in the YRB showed a first upward then a downward trend.The change curve of the slope spectrum of cropland in each province(municipality)exhibited various distribution patterns.Quantitative analysis of morphological parameters of cropland slope spectrum revealed that the further down the YRB,the stronger the flattening characteristics,the more obvious the concentration.The province experienced the greatest downhill cropland climbing(CLC)was Shannxi,while province experienced the highest uphill CLC was Zhejiang.The most common cropland use change type in the YRB was horizontal expansion type.The factors affecting average cropland climbing index(ACCI)were quite stable in different periods,while population density(POP)changed from negative to positive during the study period.This research is of practical significance for the rational utilization of cropland at the watershed scale. 展开更多
关键词 Cropland climbing Land use change Slope spectrum Driving factors Geographically weighted regression Yangtze River Basin
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BL Lacertae: Hard Optical Spectrum and GeV γ-ray Emission
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作者 Shan-JieQian Xi-ZhenZhang T.P.Krichbaum 《Chinese Journal of Astronomy and Astrophysics》 CSCD 北大核心 2004年第3期231-246,共16页
The spectral energy distribution (SED) of the γ-ray flare observed inJuly 1997 in BL Lacertae is re-considered. It is pointed out that the optical observa-tions made by Webb et al. showed the associated optical flare... The spectral energy distribution (SED) of the γ-ray flare observed inJuly 1997 in BL Lacertae is re-considered. It is pointed out that the optical observa-tions made by Webb et al. showed the associated optical flare has a hard spectrum(the average spectral index αopt~ 0.48, F_v∝v^(-α)), and the ASCA observationsmade by Tanihata et al. showed very steep spectra in the soft X-ray band (0.7-1.5 keV) (α_x~3-4). We find that the flux densities and spectral indices in both theoptical and soft X-ray bands are closely consistent with a ‘canonical' synchrotronspectrum emitted by relativistic electrons of a power-law energy distribution witha high energy cutoff, and thus the peak of the SED of the synchrotron radiation (inrepresentation of vF_v) is located in the EUV -- soft X-ray bands. Therefore, theGeV γ-ray emission observed in the July 1997 outburst may be mainly due to thesynchrotron self-Compton (SSC) process, contrasting with the current explanationsin terms of external radiation Compton (ERC) process, in which the seed photonsare mostly taken to be the UV emission from the clouds of the broad emission lineregion. We argue that the hard optical spectra observed during the γ-ray outburstmay be an important signature for the acceleration of high energy electrons (γ_e~10~4)in the γ-ray emitting region. 展开更多
关键词 galaxies:compact gamma rays:observations quasars:individual:BL Lacertae
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Actual implementation of spectrum-sharing systems in rayleigh fading channels~
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作者 裴二荣 Wang Sheng Zhang Zhizhong 《High Technology Letters》 EI CAS 2012年第2期145-150,共6页
In actual implementation of spectrum sharing systems, due to the selfishness of primary users, primary users often refuse the access of secondary users to their licensed spectrum bands even if the access of secondary ... In actual implementation of spectrum sharing systems, due to the selfishness of primary users, primary users often refuse the access of secondary users to their licensed spectrum bands even if the access of secondary users doesn't affect their transmission. Aimed at the selfishness problem of primary users, a seller's market trading mechanism is introduced which can not only stimulate primary users to tolerate larger interference power but also give the primary users an appropriate compensation at the same time, and which has very important practical significance. Based on the mechanism, the achievable maximal gross profit of secondary users and their optimal power allocation scheme in the Rayleigh fading environment are derived, and the interference price of primary users and the average revenue of secondary users' impact on them are also studied. Numerical calculation results are conducted to verify our theoretical results. 展开更多
关键词 cognitive radio spectrum sharing power allocation seller's market trading mechanism CONVEXOPTIMIZATION
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