检索结果-南通市图书馆

Comprehensive drought monitoring in yunnan Province, China using multisource remote sensing data

Journal of Mountain Science 2021年第6期18卷 1537-1549页

作者： WANG Jin-liang yu yuan-he Faculty of Geography Yunnan Normal UniversityKunming 650500China Key Laboratory of Resources and Environmental Remote Sensing for Universities in yunnan Kunming 650500China Center for Geospatial Information Engineering and Technology of yunnan Province Kunming 650500China

Development of drought monitoring techniques is important for understanding and mitigating droughts and for rational agricultural management. This study used data from multiple sources, including MOD13 A3, TRMM 3 B43, and SRTMDEM, for yunnan Province, China from 2009 to 2018 to calculate the tropical rainfall condition index(TRCI), vegetation condition index(VCI), temperature condition index(TCI), and elevation factors. Principal component analysis(PCA) and analytic hierarchy process(AHP) were used to construct comprehensive drought monitoring models for yunnan Province. The reliability of the models was verified, following which the drought situation in yunnan Province for the past ten years was analysed. The results showed that:(1) The comprehensive drought index(CDI) had a high correlation with the standardized precipitation index, standardized precipitation evapotranspiration index, temperature vegetation dryness index, and CLDAS(China Meteorological Administration land data assimilation system), indicating that the CDI was a strong indicator of drought through meteorological, remote sensing and soil moisture monitoring.(2) The droughts from 2009 to 2018 showed generally consistent spatiotemporal changes. Droughts occurred in most parts of the province, with an average drought frequency of 29% and four droughtprone centres.(3) Monthly drought coverage during 2009 to 2014 exceeded that over 2015 to 2018. January had the largest average drought coverage over the study period(61.92%). Droughts at most stations during the remaining months except for October exhibited a weakening trend(slope > 0). The CDI provides a novel approach for drought monitoring in areas with complex terrain such as yunnan Province.

关键词： Multisource data Comprehensive drought index(CDI) Standardized precipitation index(SPI) Standardized precipitation evapotranspiration index(SPEI) Temperature vegetation dryness index(TVDI) yunnan Province China

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Reassessment subacute MPTP-treated mice model of Parkinson disease

引用

中国药理学与毒理学杂志 2017年第10期31卷 1024-1025页

作者： Lu WEN yu-he yuan Nai-hong CheN State Key Laboratory of Bioactive Substances and Functions of Natural Medicines Institute of Materia Medica& Neuroscience CenterChinese Academy of Medical Sciences and Peking Union Medical College College of Pharmacy Hunan University of Chinese Medicine

OBJECTIVE(1) To estimate the value of the subacute MPTP mouse model in aspects of behavioral performance,biochemical changes and pathological abnormalities.(2) To find effective positive *** Male C57 BL/6 mice were injected with MPTP(30 mg·kg^(-1)·d^(-1),ip) for 5 consecutive *** days before MPTP injection,the mice were orally administered selegiline(3 mg·kg^(-1)·d^(-1)),pramipexole(3 mg·kg^(-1)·d^(-1)),or medopar(100 mg·kg^(-1)·d^(-1)) for 18 *** performance was assessed in the open field test,pole test and rotarod *** in the striatum were detected using *** levels were measured by Western *** characteristics were examined by *** changes were observed by electron *** The subacute MPTP treatment did not induce evident motor defects despite severe injuries in the dopaminergic ***,MPTP significantly increased the α-synuclein levels and the number of astrocytes in the striatum,and destroyed the blood-brain barrier(BBB) in the substantianigra pars *** selegiline and pramipexole were able to protect the mice against MPTP *** The subacute MPTP mouse model does not show visible motor defects;it is not enough to evaluate the validity of a candidate just based on behavioral examination,much attention should also be paid to the alterations in neurotransmitters,astrocytes,α-synuclein and the *** addition,selegiline or pramipexole is a better choice than medopar as an effective positive control for the subacute MPTP model.

关键词： subacute MPTP model Parkinson disease selegiline pramipexole α-synuclein

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A regression approach for seismic first-break picking

引用

Petroleum Science 2024年第3期21卷 1584-1596页

作者： Huan yuan San-Yi yuan Jie Wu Wen-Jing Sang yu-he Zhao CNPC Key Laboratory of Geophysical Exploration China University of Petroleum(Beijing)Beijing 102249China Research Institute of Petroleum Exploration&Development—Northwest(NWGI) Key Laboratory of reservoir characterization of CNPCPetroChinaLanzhou 730020GansuChina

The picking efficiency of seismic first breaks(FBs)has been greatly accelerated by deep learning(DL)***,the picking accuracy and efficiency of DL methods still face huge challenges in low signal-to-noise ratio(SNR)*** address this issue,we propose a regression approach to pick FBs based on bidirectional long short-term memory(Bi LSTM)neural network by learning the implicit Eikonal equation of 3D inhomogeneous media with rugged topography in the target *** employ a regressive model that represents the relationships among the elevation of shots,offset and the elevation of receivers with their seismic traveltime to predict the unknown FBs,from common-shot gathers with sparsely distributed *** from image segmentation methods which automatically extract image features and classify FBs from seismic data,the proposed method can learn the inner relationship between field geometry and *** addition,the predicted results by the regressive model are continuous values of FBs rather than the discrete ones of the binary *** picking results of synthetic data shows that the proposed method has low dependence on label data,and can obtain reliable and similar predicted results using two types of label data with large *** picking results of9380 shots for 3D seismic data generated by vibroseis indicate that the proposed method can still accurately predict FBs in low SNR *** subsequent stacked profiles further illustrate the reliability and effectiveness of the proposed *** results of model data and field seismic data demonstrate that the proposed regression method is a robust first-break picker with high potential for field application.

关键词： First-break picking Low signal-to-noiseratio Regression BiLSTM Traveltime Geometry Noisy seismic data

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Numerical simulation of transient characteristics in a bulb turbine during the load rejection process

引用

Journal of Hydrodynamics 2024年第1期36卷 170-183页

作者： yue Lu yu-quan Zhang Zhong-wei he yuan Zheng College of Water Conservancy and Hydropower Engineering Hohai UniversityNanjing210098China College of Energy and Electrical Engineering Hohai UniversityNanjing210098China Huadong Engineering Corporation Ltd. Hangzhou311122China

To evaluate the safety of the bulb tubular turbine,the dynamic hydraulic characteristics of a hydropower station system during the load rejection process are studied through numerical simulations and a prototype *** the developed model,a dynamic grid technology(DGT)controls the closure of the guide vane and the blade,whilst the moment balance equation and the user-defined function(UDF)provide the runner’s rotation *** 3-D transient simulation method can well predict the rotation speed and mass flow curves in the state of load *** simulation outcomes of the system performance are basically consistent with the measurement data of the *** observed,the runner is subjected to the reversely increased torque and axial force,the system is in a braking phase,and the maximum speed peaks at 144.6%of the rated ***,the internal flow of the runner is greatly affected by the closure of the guide vane,and the draft tube forms an eccentric spiral vortex *** breaks downstream,aggravating the instability of the draft ***,the transient characteristics span for the first five seconds,demonstrating the importance of establishing an efficient governing *** obtained results are useful for designing the turbine’s flow channel with a double regulating function and comprehending the turbine’s transient characteristics.

关键词： Bulb tubular turbine load rejection numerical simulation dynamic grid prototype test

来源：

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

20C,a new bibenzyl compound,plays a significant role in rotenone-induced oxidative insult

引用

中国药理学与毒理学杂志 2017年第10期31卷 1008-1009页

作者： Xiao-ling ZHANG yu-he yuan Nai-hong CheN State Key Laboratory of Bioactive Substances and Functions of Natural Medicines Institute of Materia Medica & Neuroscience CenterChinese Academy of Medical Sciences and Peking Union Medical College College of Pharmacy Hunan University of Chinese Medicine

20C,a bibenzyl compound isolated from Gastrodia elata,possesses antioxidative properties in PC12 cells,but its in-depth molecular mechanisms against rotenone-induced neurotoxicity remains *** studies indicate that without intact DJ-1,nuclear factor erythroid 2-related factor(Nrf2)protein becomes unstable,and the activity of Nrf2-mediated downstream antioxidant enzymes are thereby ***,increasing the nuclear translocation of Nrf2 by DJ-1 may present a helpful means for the prevention and treatment of chronic diseases related to oxidative *** results showed that 20C clearly protected PC12 and SH-SY5Y cells against rotenone-induced oxidative injury in a concentration-dependent ***,20C markedly up-regulated the levels of DJ-1,which in turn activated phosphoinositide-3-kinase(PI3K)/Akt signaling and inhibited glycogen synthase kinase 3β(GSK3β)activation,eventually promoting Nrf2 nuclear translocation and inducing the expression of Nrf2-mediated downstream antioxidative enzymes such as *** antioxidative effects of 20C could be partially blocked by ShR NA-mediated knockdown of DJ-1 and inhibition of the PI3K/Akt pathways with Akt1/2 kinase inhibitor in PC12 and SH-SY5Y cells,***,our findings confirm that DJ-1 is necessary for 20C-mediated protection against rotenone-induced oxidative damage,at least in part,by activating PI3K/Akt signaling,and subsequently enhancing the nuclear accumulation of *** findings from our investigation suggest that 20C should be developed as a novel candidate for preventing or alleviating the consequences of PD in the future.

关键词： 20C Parkinson disease DJ-1 Akt oxidative stress nuclear factor erythroid 2-related factor(Nrf2)

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Ginsenoside Rg1 attenuates motor impairment and neuroinflammation in the MPTP-probenecid-induced parkinsonism mouse model

引用

中国药理学与毒理学杂志 2017年第10期31卷 999-1000页

作者： Qian-hang SHAO yu-he yuan Nai-hong CheN State Key Laboratory of Bioactive Substances and Functions of Natural Medicines Institute of Materia Medica & Neuroscience CenterChinese Academy of Medical Sciences and Peking Union Medical College College of Pharmacy Hunan University of Chinese Medicine

OBJECTIVE To evaluate these activities of Rg1 in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP)/probenecid(MPTP/p)-induced PD mouse model for the first time and to elucidate the underlying *** Male C57BL/6 mice were randomly assigned to six *** hour prior to MPTP/p injection,GroupⅢ-Ⅵmice received 10 mg·kg^(-1),20 mg·kg^(-1),or 40 mg·kg^(-1) Rg1 or 3 mg·kg^(-1) selegiline,respectively,orally from D(-3) to ***Ⅰ-Ⅱmice received solvent ***,GroupⅡ-Ⅵmice received by injection MPTP-HCl(25 mg·kg^(-1) bw dissolved in0.9%saline,sc)on a 40-d schedule at intervals of 4 d between consecutive doses in combination with an adjuvant drug,probenecid(250 mg·kg^(-1) bw in 0.03 mL of DMSO,ip);GroupⅠmice were injected with saline and *** performance was assessed in the open field test,pole test and rotarod *** in the striatum were detected using *** levels were measured by Western *** characteristics were examined by *** changes were observed by electron *** Oral treatment with Rg1 significantly attenuated the high MPTP-induced mortality,behavior defects,loss of dopamine neurons and abnormal ultrastructure changes in the *** assays indicated that the protective effect of Rg1 may be mediated by its anti-neuroinflammatory ***1 regulated MPTP-induced reactive astrocytes and microglia and decreased the release of cytokines such as tumor necrosis factor-α(TNF-α)and interleukin-1b(IL^(-1)b)in the ***1 also al eviated the unusual MPTP induced increase in oligomeric,phosphorylated and disease-related a-synuclein in the *** Rg1 protects dopaminergic neurons,most likely by reducing aberrant a-synuclein-mediated neuroinflammation,and holds promise for Parkinson disease therapeutics.

关键词： Parkinson disease neuroinflammation a-synuclein ginsenoside Rg1 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Evaluation and Influencing Factors on Particle Agglomeration in RAP

引用

Journal of Wuhan University of Technology(Materials Science) 2024年第1期39卷 60-68页

作者：唐伟李宁 ZHUANG yuan ZHAN he yu Xin WU Wenxiu DING Gongying College of Civil and Transportation Engineering Hohai UniversityNanjing 210098China Jiangsu Expressway Engineering Maintenance Technology Center Nanjing 211106China Jinhua Highway and Transportation Management Center Jinhua 321000China

Asphalt extraction test and scanning electron microscopy(SEM) were used for analysis of agglomerations of reclaimed asphalt pavement(RAP) particles. In order to quantify the agglomeration degree of RAP, the fineness modulus ratio(FMR) and the percentage loss index(PLI) were proposed. In addition, grey correlation analysis was conducted to discuss the relationship between particle agglomerations and RAP size,asphalt content(AC), and surface area. Two indexes indicate that the agglomeration degree increases in general as the RAP size reduces. This can be attributed to that particles are prone to agglomeration in the case of higher AC. Based on the SEM images and the material composition of RAP, the particle agglomeration in RAP can be classified into weak agglomeration and strong agglomeration. Grey correlation analysis shows that AC is the crucial factor affecting the agglomeration degree and RAP variability. In order to produce consistent and stable reclaimed mixtures, disposal measures of RAP are suggested to lower the AC of RAP.

关键词： RAP particle agglomeration grey correlation analysis asphalt content

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

CS-FSCL decoding algorithm of polar codes based on critical sets

引用

Optoelectronics Letters 2024年第7期20卷 418-423页

作者： yuan Jianguo ZHANG Fengguo he Jingjie PANG yu School of Optoelectronic Engineering Chongqing University of Posts and TelecommunicationsChongqing 400065China1

In order to reduce the number of redundant candidate codewords generated by the fast successive cancellation list(FSCL)decoding algorithm for polar codes,a simplified FSCL decoding algorithm based on critical sets(CS-FSCL)of polar codes is *** algorithm utilizes the number of information bits belonging to the CS in the special nodes,such as Rate-1 node,repetition(REP)node and single-parity-check(SPC)node,to constrain the number of the path splitting and avoid the generation of unnecessary candidate codewords,and thus the latency and computational complexity are ***,the algorithm only flips the bits corresponding to the smaller log-likelihood ratio(LLR)values to generate the sub-maximum likelihood(sub-ML)decoding codewords and ensure the decoding *** results show that for polar codes with the code length of 1024,the code rates of 1/4,1/2 and 3/4,the proposed CS-FSCL algorithm,compared with the conventional FSCL decoding algorithm,can achieve the same decoding performance,but reduce the latency and computational complexity at different list ***,under the list size of L=8,the code rates of R=1/2 and R=1/4,the latency is reduced by 33%and 13%and the computational complexity is reduced by 55%and 50%,respectively.

关键词： algorithm FSC critical

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Force Compensation Control for Electro-Hydraulic Servo System with Pump-Valve Compound Drive via QFT-DTOC

引用

Chinese Journal of Mechanical Engineering 2024年第2期37卷 228-246页

作者： Kaixian Ba yuan Wang Xiaolong he Chunyu Wang Bin yu Yaliang Liu Xiangdong Kong hebei Provincial Key Laboratory of heavy Machinery Fluid Power Transmission and Control Qinhuangdao 066004China School of Mechanical Engineering Yanshan UniversityQinhuangdao 066004China National Engineering Research Center for Local Joint of Advanced Manufacturing Technology and Equipment Yanshan UniversityQinhuangdao 066004China

Each joint of a hydraulic-driven legged robot adopts a highly integrated hydraulic drive unit(HDU),which features a high power-weight ***,most HDUs are throttling-valve-controlled cylinder systems,which exhibit high energy *** contrast,pump control systems offer a high ***,their response ability is *** fully utilize the advantages of pump and valve control systems,in this study,a new type of pump-valve compound drive system(PCDS)is designed,which can not only effectively reduce the energy loss,but can also ensure the response speed and response accuracy of the HDUs in robot joints to satisfy the performance requirements of ***,considering the force control requirements of energy conservation,high precision,and fast response of the robot joint HDU,a nonlinear mathematical model of the PCDS force control system is first *** addition,pressure-flow nonlinearity,friction nonlinearity,load complexity and variability,and other factors affecting the system are considered,and a novel force control method based on quantitative feedback theory(QFT)and a disturbance torque observer(DTO)is designed,which is denoted as QFT-DTOC *** method improves the control accuracy and robustness of the force control system,reduces the effect of the disturbance torque on the control performance of the servo motor,and improves the overall force control performance of the ***,experimental verification is performed using the PCDS performance test *** experimental results and quantitative data show that the QFT-DTOC proposed herein can significantly improve the force control performance of the *** relevant force control method can be used as a bottom-control method for the hydraulic servo system to provide a foundation for implementing the top-level trajectory planning of the robot.

关键词： Legged robot Pump-valve compound drive system(PCDS) Force compensation control Quantitative feedback theory(QFT) Disturbance torque observer(DTO)

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Answering reachability queries with ordered label constraints over labeled graphs

引用

Frontiers of Computer Science 2024年第1期18卷 105-117页

作者： Daoliang he Pingpeng yuan Hai JIN National Engineering Research Center for Big Data Technology and System Services Computing Technology and System LabCluster and Grid Computing LabSchool of Computer Science&TechnologyHuazhong University of Science and TechnologyWuhan 430074China

Reachability query plays a vital role in many graph analysis *** researches proposed many methods to efficiently answer reachability queries between vertex *** many real graphs are labeled graph,it highly demands Label-Constrained Reachability(LCR)query inwhich constraint includes a set of labels besides vertex *** researches proposed several methods for answering some LCR queries which require appearance of some labels specified in constraints in the *** that constraint may be a label set,query constraint may be ordered labels,namely OLCR(Ordered-Label-Constrained Reachability)queries which retrieve paths matching a sequence of ***,no solutions are available for ***,we propose DHL,a novel bloom filter based indexing technique for answering OLCR *** can be used to check reachability between vertex *** the answers are not no,then constrained DFS is ***,we employ DHL followed by performing constrained DFS to answer OLCR *** show that DHL has a bounded false positive rate,and it's powerful in saving indexing time and *** experiments on 10 real-life graphs and 12 synthetic graphs demonstrate that DHL achieves about 4.8-22.5 times smaller index space and 4.6-114 times less index construction time than two state-of-art techniques for LCR queries,while achieving comparable query response *** results also show that our algorithm can answer OLCR queries effectively.

关键词： graph ordered-label-constrained reachability partial index bloom filter query processing

来源：

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

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：