检索结果-南通市图书馆

Deep learning for fast channel estimation in millimeter-wave MIMO systems

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2022年第6期33卷 1088-1095页

作者： LYU Siting LI Xiaohui FAN Tao LIU Jiawen SHI Mingli School of Telecommunication Engineering Xidian UniversityXi’an 710071China State Key Laboratory of Integrated Service Networks Xidian UniversityXi’an 710071China

Channel estimation has been considered as a key issue in the millimeter-wave(mmWave)massive multi-input multioutput(MIMO)communication systems,which becomes more challenging with a large number of antennas.In this paper,we propose a deep learning(DL)-based fast channel estimation method for mmWave massive MIMO systems.The proposed method can directly and effectively estimate channel state information(CSI)from received data without performing pilot signals estimate in advance,which simplifies the estimation process.Specifically,we develop a convolutional neural network(CNN)-based channel estimation network for the case of dimensional mismatch of input and output data,subsequently denoted as channel(H)neural network(HNN).It can quickly estimate the channel information by learning the inherent characteristics of the received data and the relationship between the received data and the channel,while the dimension of the received data is much smaller than the channel matrix.Simulation results show that the proposed HNN can gain better channel estimation accuracy compared with existing schemes.

关键词： millimeter-wave(mmWave) channel estimation deep learning(DL) dimensional mismatch channel state information(CSI)

Auger effect in weakly confined nanocrystals

在线全文

学校读者我要写书评

暂无评论

光:科学与应用(英文版) 2023年第8期12卷 1454-1456页

作者： jiawen liu Laurent Coolen Laboratoire de Physique de I'Ecole Normale Superieure ENSUniversite PSLCNRSSorbonne UniversiteUniversite Paris CiteF-75005 ParisFrance Sorbonne Universite CNRSInstitut de NanoSciences de ParisINSPF-75005 ParisFrance

An extensive analysis of biexciton luminescence in high-quality,large perovskite CsPbBr_(3) nanocrystals shows how the biexciton Auger decay rate deviates from the"universal"volume scaling as the exciton confinement b... 详细信息

关键词： weakly confined perovskite

The salt-activated CBF1/CBF2/CBF3-GALS1 module fine-tunes galactan-induced salt hypersensitivity in Arabidopsis

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Integrative Plant Biology 2023年第8期65卷 1904-1917页

作者： Jingwei Yan Ya liu jiawen Yan Zhihui liu Heqiang Lou Jiasheng Wu State Key Laboratory of Subtropical Silviculture Zhejiang A&F UniversityHangzhou 311300China

Plant growth and development are significantly hampered in saline environments,limiting agricultural productivity.Thus,it is crucial to unravel the mechanism underlying plant responses to salt stress.β-1,4-Galactan(galactan),which forms the side chains of pectic rhamnogalacturonan I,enhances plant sensitivity to high-salt stress.Galactan is synthesized by GALACTAN SYNTHASE1(GALS1).We previously showed that Na Cl relieves the direct suppression of GALS1 transcription by the transcription factors BPC1 and BPC2 to induce the excess accumulation of galactan in Arabidopsis(Arabidopsis thaliana).However,how plants adapt to this unfavorable environment remains unclear.Here,we determined that the transcription factors CBF1,CBF2,and CBF3 directly interact with the GALS1 promoter and repress its expression,leading to reduced galactan accumulation and enhanced salt tolerance.Salt stress enhances the binding of CBF1/CBF2/CBF3 to the GALS1 promoter by inducing CBF1/CBF2/CBF3 transcription and accumulation.Genetic analysis suggested that CBF1/CBF2/CBF3 function upstream of GALS1 to modulate salt-induced galactan biosynthesis and the salt response.CBF1/CBF2/CBF3 and BPC1/BPC2 function in parallel to regulate GALS1 expression,thereby modulating the salt response.Our results reveal a mechanism in which salt-activated CBF1/CBF2/CBF3 inhibit BPC1/BPC2-regulated GALS1 expression to alleviate galactan-induced salt hypersensitivity,providing an activation/deactivation fine-tune mechanism for dynamic regulation of GALS1 expression under salt stress in Arabidopsis.

关键词： Arabidopsis thaliana BPC1/BPC2 CBF1/CBF2/CBF3 β-1,4-galactan GALS1 salt stress

Microplastics in sediment of the Three Gorges Reservoir:abundance and characteristics under different environmental conditions

在线全文

学校读者我要写书评

暂无评论

Journal of Oceanology and Limnology 2024年第1期42卷 101-112页

作者： Wang LI Bo ZU Yiwei liu Juncheng GUO jiawen LI College of River and Ocean Engineering Chongqing Jiaotong UniversityChongqing 400074China Chongqing Research Academy of Ecology and Environmental Sciences Chongqing 401147China

Freshwater microplastic pollution is an urgent issue of global concern,and research on the distribution in reservoirs is lacking.We investigated the microplastic pollution levels in wet sediments collected from the Three Gorges Reservoir,the largest reservoir of China.Results show that microplastics were ubiquitous in the sediments of the Three Gorges Reservoir,and their abundance ranged from 59 to 276 pp/kg(plastic particles per kg,dry weight).Economic development and total population were important factors affecting the spatial heterogeneity of microplastic abundance,and the contribution of large cities along the reservoir to microplastic pollution should be paid with more attention.Fibrous microplastics were the most abundant type of microplastic particles in reservoir sediments,whereas polystyrene,polypropylene,and polyamide were the main types of polymers.The apparent spatial heterogeneity in morphology and color of microplastics is attributed to different anthropogenic or landbased pollution sources.Moreover,the accumulation of microplastics near the inlet of tributaries reflects the role of potential contributors of tributaries.More importantly,multiple bisphenols(BPs)and heavy metals detected at the microplastic surfaces indicate that microplastics can act as carriers of these pollutants in the environment in the same way as sediments did,which may alter the environmental fate and toxicity of these pollutants.Therefore,we conclude that the Three Gorges Reservoir had been contaminated with microplastics,which posed a stress risk for organisms who ingest them along with their associated pollutants(BPs,heavy metals).

关键词： microplastics Three Gorges Reservoir sediment bisphenol heavy metal

Brain structure and structural basis of neurodegenerative diseases

在线全文

学校读者我要写书评

暂无评论

Biophysics Reports 2022年第3期8卷 170-181页

作者： jiawen Yang Sen-Fang Sui Zheng liu Cryo-electron Microscopy Center Southern University of Science and Technology Department of Biology Southern University of Science and Technology State Key Laboratory of Membrane Biology Beijing Advanced Innovation Center for Structural Biology Beijing Frontier Research Center for Biological Structure School of Life Sciences Tsinghua University

The brain is one of the most complex organs in nature. In this organ, multiple neurons, neuron clusters,or multiple brain regions are interconnected to form a complex structural network where various brain functions are completed through interaction. In recent years, multiple tools and techniques have been developed to analyze the composition of different cell types in the brain and to construct the brain atlas on macroscopic, mesoscopic, and microscopic levels. Meanwhile, researchers have found that many neuropsychiatric diseases, such as Parkinson’s disease, Alzheimer’s disease, and Huntington’s disease,are closely related to abnormal changes of brain structure, which means the investigation in brain structure not only provides a new idea for understanding the pathological mechanism of the diseases,but also provides imaging markers for early diagnosis and potential treatment. This article pays attention to the research of human brain structure, reviews the research progress of human brain structure and the structural mechanism of neurodegenerative diseases, and discusses the problems and prospects in the field.

关键词： Brain atlas Brain ultrastructure Neurodegenerative disease Parkinson’s disease Alzheimer’s disease Huntington’s disease

A metal-organic framework-based redox homeostasis disruptor selectively potentiate the cytotoxicity of dihydroartemisinin for cancer therapy

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5期16卷 7489-7495页

作者： jiawen Fan Xinchen liu Qishun Wang Huan Wang Hao liu Deming Han Jinsong Ren School of Life Science and Technology Changchun University of Science and TechnologyChangchun 130022China State Key Laboratory of Rare Earth Resources Utilization and Laboratory of Chemical Biology Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China Jilin Provincial Key Laboratory of Tooth Development and Bone Remodeling Hospital of StomatologyJilin UniversityChangchun 130021China Department of Chemistry Tsinghua UniversityBeijing 100084China

Artemisinin and its derivatives have emerged as promising therapeutic agents for cancer therapy by endogenous iron-mediated generation of free radicals.However,the enhanced antioxidant defense systems in cancer cells provide them with resistance to oxidative damage,greatly antagonizing the therapeutic efficacy that relies on inducing oxidative stress.Herein,a metal-organic framework(MOF)-based nanoplatform(CMD)is constructed to disrupt the cellular redox homeostasis and selectively potentiate the cytotoxicity of dihydroartemisinin for cancer therapy.In cancer cells,the copper(II)sites in the MOF nanocarrier of CMD can efficiently weaken the cellular antioxidant capacity by depleting the overexpressed glutathione,simultaneously leading to the decomposition of the framework structure and the release of the encapsulated dihydroartemisinin.As a result,the damaged antioxidant defense system of cancer cells reduces its effect on oxidative stress alleviation and strengthens the therapeutic efficacy of dihydroartemisinin.On contrast,the low concentration of cellular glutathione in normal cells protects them from dihydroartemisinin-induced cytotoxicity by decelerating the drug release.In vivo results demonstrate that CMD could completely suppress the tumor growth in mice and show no evidence of toxicity,providing an effective strategy for the practical usage of dihydroartemisinin in cancer therapy.

关键词： metal-organic framework dihydroartemisinin selective cancer therapy redox homeostasis disruptor glutathione depletion

Multivariate statistical analysis of chemical and stable isotopic data as indicative of groundwater evolution with reduced exploitation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Geoscience Frontiers 2023年第1期14卷 133-148页

作者： Fei liu Jingkun Zhang Shiqin Wang jiawen Zou Pinna Zhen School of Water Conservancy and Hydropower Hebei University of Engineering19 Taiji RoadHandanHebei 056038China Hebei Key Laboratory of Intelligent Water Conservancy HandanHebei 056038China Key Laboratory of Agricultural Water Resources Center for Agricultural Resources ResearchInstitute of Genetics and Developmental BiologyChinese Academy of SciencesShijiazhuang 050021China

Groundwater resources in the North China Plain(NCP)are undergoing tremendous changes in response to the operation of groundwater exploitation reduction(GWER)project.To identify groundwater evolution in this complex context,hierarchical cluster analysis(HCA)and principal component analysis(PCA)were combined to interpret an integrated dataset of stable isotopes and chemical data from four sampling campaigns in a pilot area of groundwater control.We proposed a novel HCA approach integrating stable isotopes and chemical signals,which successfully partitioned the groundwater samples into the unconfined and the confined water samples.Stable isotopic evidence showed that the lateral inflow and the surface water may contribute more to groundwater recharge in this region than local modern precipitation.The unconfined water's main hydrochemical types were Na type with mixed anions,and Na-Cl-SO_(4)type,while the confined water was mainly Na-Cl and Na-SO_(4)types.Geochemical processes mainly involved the dissolution/precipitation of halite,gypsum,Glauber's salt,feldspar,calcite and dolomite,as well as the cation exchange.PCA results showed that water-rock interaction(i.e.,salinity-based and alkalinity-based processes)predominated the hydrochemical evolution,along with local nitrate contamination resulting from fertilizers and domestic sewage.The GWER project regulated the natural evolution of unconfined water chemistry,and significantly reduced the unconfined water's salinity(mainly Na^(+),Mg^(2+),SO_(4)^(2-)).This may be attributed to upward leakage from low-salinity confined water at some parts of the aquifer.Additionally,insignificant changes in the confined water's salinity reflected that the impact of GWER on the confined aquifer was negligible.This study facilitates the groundwater classification effectively in the areas lack of geological data,and enhances the knowledge of groundwater chemical evolution in such a region where groundwater restoration is in progress,with important implications for groundwater sustainabl

关键词： Hydrochemistry Stable isotopes Groundwater evolution Groundwater exploitation reduction Hierarchical cluster analysis Principal component analysis

Preparation optimization of multilayer-structured SnO_2–Sb–Ce/Ti electrode for efficient electrocatalytic oxidation of tetracycline in water

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 Chemical Engineering 2018年第12期26卷 2622-2627页

作者： Kun Yang Yuyu liu jiawen liu Jinli Qiao Institute of Sustainable Energy/College of Science Shanghai UniversityShanghai 200444China State Environmental Protection Engineering Center for Pollution Treatment and Control in Textile Industry College of Environmental Science and EngineeringDonghua UniversityShanghai 201620China ShanghaiJinyuan Senior High School Shanghai 200333China

In this study, electrodeposition and thermal decomposition were alternatively used for the fabrication of a series of novel multilayer-structured SnO_2–Sb–Ce/Ti(SSCT) electrodes, and their physiochemical and electrochemical properties were investigated for electrochemical oxidation of tetracycline(TC) in aqueous medium.Experimentally, after the SnO_2–Sb–Ce(SSC) composite was electrodeposited for 120 s on the titanium substrate in aqueous solution, the outer thermal coatings composed of SSC were synthesized by a hydrothermal method.Both influences of electrodeposition time(T_(ed)) and thermal decomposition time(Ttd) were investigated to obtain the optimum preparation. It was found that when increasing T_(ed)to a certain extent a longer lifetime of electrode can be achieved, which was attributed to a more solid interlayer structure. A notable SSCTT_(ed),Ttdelectrode,i.e., SSCT3,10, which was prepared through three times of 120 s' electrodeposition(T_(ed)= 3) and ten times of thermal decomposition(Ttd= 10) obtained the highest oxygen evolution potential 3.141 V vs. SCE. In this selected electrode, when 10 mg·L^(-1) initial TC concentration was added to this wastewater, the highest color removal efficiency and mineralization rate of TC were 72.4% and 41.6%, respectively, with an applied electricity density of 20 m A·cm^(-2) and treatment time of 1 h. These results presented here demonstrate that the combined application of electrodeposition and thermal decomposition is effective in realization of enhanced electrocatalytic oxidation activity.

关键词： Multilayer structured electrode Nano-hollow sphere Antibiotics Electro-oxidation

Recent advances on catalysts for preferential oxidation of CO

在线全文

学校读者我要写书评

暂无评论

Nano Research 2023年第4期16卷 4399-4410页

作者： Huimin liu Dezheng Li jiawen Guo Yuqiao Li Aidi liu Yitong Bai Dehua He School of Chemical and Environmental Engineering Liaoning University of TechnologyJinzhou 121001China Innovative Catalysis Program Key Lab of Organic Optoelectronics&Molecular Engineering of Ministry of EducationDepartment of ChemistryTsinghua UniversityBeijing 100084China

The trace amount of CO in H2-rich gas poisons Pt electrode when it is adopted as feedstock for proton-exchange-membrane fuel cells.Preferential oxidation of CO(PROX)is a promising approach to selectively oxidize the trace amount of CO while keeping H2 unoxidized.Catalyst plays important roles in PROX.To date,enormous catalysts have been developed for PROX.Summarizing the catalysts developed for PROX and unveiling the reaction mechanism could definitely advance this research field.Herein,in this review,according to the nature of the active sites on the catalysts,we classify the catalysts into group VIII metal-based catalyst,group IB metal-based catalysts,group VIII-group IB bimetallic catalysts,transitional metal oxide catalysts as well as others,describe the progress of the catalysts in PROX in the latest five years,and extract the underlying reaction mechanism,with the aim to provide guidance for the rational design of efficient catalysts in the future.

关键词： preferential oxidation of CO group VIII metal-based catalysts group IB metal-based catalysts bimetallic catalysts mechanism exploration