期刊文献+
共找到18,312篇文章
< 1 2 250 >
每页显示 20 50 100
Simultaneous determination of three curcuminoids in Curcuma longa L.by high performance liquid chromatography coupled with electrochemical detection 被引量:4
1
作者 Yuling Long Wenpeng Zhang +1 位作者 Fang Wang Zilin Chen 《Journal of Pharmaceutical Analysis》 SCIE CAS 2014年第5期325-330,共6页
A novel method for analysis of three active components curcumin, demethoxycurcumin and bisdemethoxycurcumin in Curcuma longa L. was developed by HPLC coupled with electrochemical detection. Three curcuminoids were wel... A novel method for analysis of three active components curcumin, demethoxycurcumin and bisdemethoxycurcumin in Curcuma longa L. was developed by HPLC coupled with electrochemical detection. Three curcuminoids were well separated on a C18 column and detected with high sensitivity. A mobile phase containing acetonitrile and 10 mM Na2HPO4-H3PO4 (pH 5.0) (50:50, v/v) was used. Good linearity was obtained in the range of 0.208-41.6, 0.197-39.4, and 0.227-114μM for curcumin, demethoxycurcumin and bisdemethoxycurcumin respectively. The limit of detection reached up to 10 ? 8 M, which was lower than that by UV detection. The relative standard deviations (RSDs) ranged from 1.06%to 1.88%for intra-day precision and from 4.30%to 5.79%for inter-day precision, respectively. The proposed method has been applied in real herb sample and recoveries ranging from 86.3%to 111%were obtained. 展开更多
关键词 CURCUMIN High performance liquidchromatography Electrochemical detec- tion Curcuma longa L.
下载PDF
Feasibility of Trace Alcohol Congener Detection and Identification Using Laser-Induced Breakdown Spectroscopy 被引量:1
2
作者 张家良 王尚民 +2 位作者 赵丽贤 刘莉莹 王德真 《Plasma Science and Technology》 SCIE EI CAS CSCD 2014年第12期1119-1125,共7页
In this paper, a feasible scheme is reported for the detection and identification of trace alcohol congeners that have identical elemental composition using laser-induced breakdown spectroscopy (LIBS). In the scheme... In this paper, a feasible scheme is reported for the detection and identification of trace alcohol congeners that have identical elemental composition using laser-induced breakdown spectroscopy (LIBS). In the scheme, an intensive pulsed laser is used to break down trace alcohol samples and the optical emission spectra of the induced plasma are collected for the detection and identifq ication of alcohol molecules. In order to prepare trace alcohol samples, pure ethanol or methanol is bubbled by argon carrier gas and then mixed into matrix gases. The key issue for the scheme is to constitute indices from the LIBS data of the alcohol samples. Two indices are found to be suitable for alcohol detection and identification. One is the emission intensity ratio (denoted as H/C) of the hydrogen line (653.3 nm) to the carbon line (247.9 nm) for identification and the other is the ratio of the carbon line (as C/Ar) or the hydrogen line (as H/Ar) to the argon lines (866.7 nm) for quantitative detection. The calibration experiment result shows that the index H/C is specific for alcohol congeners while almost being independent of alcohol concentration. In detail, the H/C keeps a specific constant of 34 and 23 respectively for ethanol and methanol. In the meanwhile, the C/Ar and H/Ar indices respond almost linearly to the alcohol concentration below 1300 ppm, and are therefore competent for concentration measurement. With the indices, trace alcohol concentration measurement achieves a limit of 140 ppm using a laser pulse energy of 300 mJ. 展开更多
关键词 laser-induced breakdown spectroscopy alcohol congener quantitative detec-tion molecular identification
下载PDF
Filtering algorithm of line structured light for long-distance obstacle detection
3
作者 邵海燕 张振海 李科杰 《Journal of Beijing Institute of Technology》 EI CAS 2016年第4期521-525,共5页
Since unmanned ground vehicles often encounter concave and convex obstacles in wild ground, a filtering algorithm using line structured light to detect these long distance obstacles is proposed. For the line structure... Since unmanned ground vehicles often encounter concave and convex obstacles in wild ground, a filtering algorithm using line structured light to detect these long distance obstacles is proposed. For the line structured light image, a ranked-order based adaptively extremum median (RAEM) filter algorithm on salt and pepper noise is presented. In the algorithm, firstly effective points and noise points in a filtering window are differentiated; then the gray values of noise points are replaced by the medium of gray values of the effective pixels, with the efficient points' gray values unchanged; in the end this algorithm is proved to be efficient by experiments. Experimental resuits demonstrate that the image blur, resulting into proposed algorithm can remove noise points effectively and minimize the protecting the edge information as much as possible. 展开更多
关键词 unmanned ground vehicles line structured light concave and convex obstacles detec-tion ranked-order based adaptively extremum median (RAEM) filter filter algorithm
下载PDF
Cracking the Snake Detection Theory: The Subcortical Visual Pathway as a Major Player in Cultural Transformations
4
作者 Bogdan-Ioan Nicula 《World Journal of Neuroscience》 2020年第4期166-190,共25页
According to the proposed hypothesis, graphic characters trigger the subcortical visual route. The reaction discussed is very weak. Yet, its very existence has an unusual importance: characters and (occluded) venomous... According to the proposed hypothesis, graphic characters trigger the subcortical visual route. The reaction discussed is very weak. Yet, its very existence has an unusual importance: characters and (occluded) venomous snakeskin patterns reveal themselves as conflatable. Furthermore, following tractogra<span><span><span style="font-family:;" "="">- </span></span></span><span><span><span style="font-family:;" "="">phic research, a functional segregation of the subcortical pathway is to be <span>presupposed. Thus, there can’t be a later dissociation of two stimuli pre</span>viously associated. The outc</span></span></span><span><span><span style="font-family:;" "="">omes of lecture will gradually appear probabilistically <span>(much) more peaceful than encountering a venomous snake, though, and</span> thus a continuous lessening of the reaction is expectable. Here, on one hand, it is relevant that the subcortical visual pathway goes to the amygdala. The reactions we describe tap into goal-oriented processes, and they will do that un<span>fettered. On the other hand, in the case of characters, since the beginning,</span> fear has been converted into appetition to a great degree. This process should be fostered in the presence of light. In this way, luminosity might become a conditioned stimulus for attraction. In this case, a Pavlovian addiction for light <span>will foster, yet also—from the point of view of reward fee</span>ling—counterbalance the lessening of the stimulation elicited by characters. The addiction we refer to is one towards light accompanied by graphic signs. Yet, as opposed to the case of the luminous medium, the attention captured by the later ones taken for themselves is continuously reduced.</span></span></span> 展开更多
关键词 Active Inference Blindsight Delayed Detachment Hypothesis Snake detec-tion Theory Subcortical Route V2 Area V4 Area
下载PDF
Detecting Aerosols over Land from Satellites by Measuring Far IR Radiation from the Earth-Atmospheric System
5
作者 SHI Guang-Yu SUN Yuan-Long 《Atmospheric and Oceanic Science Letters》 2010年第2期111-115,共5页
In this study, a special method is proposed for detecting aerosols over land by analyzing satellitemeasured far IR radiation at three channels, 8.7, 11.5, and 12.5 lain. Sensitivity tests revealed that the behavioral ... In this study, a special method is proposed for detecting aerosols over land by analyzing satellitemeasured far IR radiation at three channels, 8.7, 11.5, and 12.5 lain. Sensitivity tests revealed that the behavioral features of radiative brightness temperatures (BTs) at these three channels with increasing optical depth are different among different types of aerosols. Analyzing how BTs and their differences, xBT (BT11.5-BT12.5) and YBT (BT8.7-BT11.5), behave with varying optical depth can help to qualitatively distinguish among aerosols and semi-quantitatively estimate their optical thicknesses. In addition, the authors found that the vertical density profile of aerosols has little impact on this method. 展开更多
关键词 aerosol remote-sensing over-land IR radia- tion brightness temperature satellite
下载PDF
Role of multi-detector computed tomography for biliary complications after liver transplantation 被引量:1
6
作者 Xiao-Chun Meng Wen-Sou Huang +4 位作者 Pei-Yi Xie Xiu-Zhen Chen Ming-Yue Cai Hong Shan Kang-Shun Zhu 《World Journal of Gastroenterology》 SCIE CAS 2014年第33期11856-11864,共9页
AIM: To investigate the diagnostic performance of multi-detector computed tomography (MDCT) in detecting biliary complications after orthotopic liver transplantation (OLT).
关键词 LIVER TRANSPLANTAtion BILIARY COMPLICAtionS Computed tomography
下载PDF
A new detection method in studying penetration depth of low-energy heavy ions in botanic samples
7
作者 LIU Feng, WANG Yu-Gang, XUE Jian-Ming, WANG Si-Xue ZHAO Wei-Jiang (Ion Beam Group, Institute of Heavy Ion Physics, Peking University, Beijing 100871) 《Nuclear Science and Techniques》 SCIE CAS CSCD 2001年第3期169-176,共8页
A new detection method has been applied to study the penetration depth of low-energy heavy ions in botanic samples. Highly oriented pyrolytic graphite (HOPG) pieces were placed behind the target samples with certain t... A new detection method has been applied to study the penetration depth of low-energy heavy ions in botanic samples. Highly oriented pyrolytic graphite (HOPG) pieces were placed behind the target samples with certain thickness to receive energetic penetrated ions during the irradiation. After irradiation, statistic number density of protrusion-like damage induced by energetic penetrated ions can be ob- tained through scanning tunneling microscope (STM) observation on the surfaces of HOPG. The results of test indicate that the detection limit can be as low as 1.0×109 protrusions/cm2. With the method, the penetration depth of at least 60μm can be detected in kidney bean slices irradiated by N+ ions with dose of 0.3-3×1017ions/cm2. 展开更多
关键词 低能重离子 植物样品 贯穿深度 探测法
下载PDF
Design of high-performance energy integrator detector for wideband radar 被引量:2
8
作者 CHANG Jiayun FU Xiongjun +1 位作者 JIANG Wen XIE Min 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2019年第6期1110-1118,共9页
Target detection for wideband radar has recently received extensive attention. The classical energy integrating(EI)detector will always accumulate excess clutter or noise energy,which leads to unacceptable performance... Target detection for wideband radar has recently received extensive attention. The classical energy integrating(EI)detector will always accumulate excess clutter or noise energy,which leads to unacceptable performance deterioration if the detection window is not selected properly. In this paper, an EI detector for the distributed targets in the Gaussian environment is proposed.First, at the stage of preparatory work, the target models are proposed, then, the problem formulation is introduced. Subsequently,in the aspect of optimizing the method of detection window search and the method of threshold setting, the detailed design stages of the proposed detector are provided. Furthermore, theoretical analyses show that the proposed detector is easy to hardware implementation, and it does not need the prior knowledge about the spatial distribution of the target scattering centers in practical radar detection application. Finally, the performance assessment conducted by Monte Carlo simulations verifies that the proposed detector outperforms the conventional detectors. 展开更多
关键词 RADAR detection distributed target integration detec tor.
下载PDF
Land Use/Land Cover Change Detection in Pokhara Metropolitan, Nepal Using Remote Sensing
9
作者 Sanjeev Kumar Raut Puran Chaudhary Laxmi Thapa 《Journal of Geoscience and Environment Protection》 2020年第8期25-35,共11页
Land use and land cover are essential for maintaining and managing the natural resources on the earth surface. A complex set of economic, demographic, social, cultural, technological, and environmental processes usual... Land use and land cover are essential for maintaining and managing the natural resources on the earth surface. A complex set of economic, demographic, social, cultural, technological, and environmental processes usually result in the change in the land use/land cover change (LULC). Pokhara Metropolitan is influenced mainly by the combination of various driving forces: geographical location, high rate of population growth, economic opportunity, globalization, tourism activities, and political activities. In addition to this, geographically steep slope, rugged terrain, and fragile geomorphic conditions and the frequency of earthquakes, floods, and landslides make the Pokhara Metropolitan region a disaster-prone area. The increment of the population along with infrastructure development of a given territory leads towards the urbanization. It has been rapidly changing due to urbanization, industrialization and internal migration since the 1970s. The landscapes and ground patterns are frequently changing on time and prone to disaster. Here a study has been carried to study on LULC for the last 18 years (2000-2018). The supervised classification on Landsat Imagery was performed and verified the classification through computing the error matrix. Besides, the water bodies and vegetation area were extracted through the Normalized Difference Water Index (NDWI) and Normalized Difference Vegetation Index (NDWI) respectively. This research shows that during the last 18 years the agricultural areas diminishing by 15.66% while urban area is increasing by 13.2%. This research is beneficial for preparing the plan and policy in the sustainable development of Pokhara Metropolitan. 展开更多
关键词 Error Matrix Land Use/Land Cover (LULC) Normalized Difference Vegeta-tion Index (NDVI) Normalized Difference Water Index (NDWI) Supervised Image Classification Remote Sensing Urban Growth
下载PDF
V-detector优化算法 被引量:4
10
作者 张凤斌 席亮 +1 位作者 王胜文 岳新 《高技术通讯》 CAS CSCD 北大核心 2012年第5期449-454,共6页
针对人工免疫系统中V-detector否定选择算法造成的检测器集合黑洞和检测器高重叠率等问题,借鉴生物免疫系统对免疫细胞的调节机制,提出了V-detector优化算法。该算法从父代产生候选检测器子代并通过检测器之间以及检测器与自体集合之... 针对人工免疫系统中V-detector否定选择算法造成的检测器集合黑洞和检测器高重叠率等问题,借鉴生物免疫系统对免疫细胞的调节机制,提出了V-detector优化算法。该算法从父代产生候选检测器子代并通过检测器之间以及检测器与自体集合之间的亲和力对比更新检测器集合,使得检测器集合对非自体空间的覆盖更加合理。通过二维仿真实验和KDDCUP99数据集实验测试,经优化后的检测器集合对非自体空间的覆盖性能有了显著提高,有效提高了系统的检测性能。 展开更多
关键词 人工免疫系统 实值 可变阈值否定选择算法 优化算法
下载PDF
Potential therapeutic benefits stemming from the thermal nature of irreversible electropora tion of solid cancers 被引量:2
11
作者 Michal Heger Allard C van der Wal +1 位作者 Gert Storm Martin J van Gemert 《Hepatobiliary & Pancreatic Diseases International》 SCIE CAS CSCD 2015年第3期331-333,共3页
To the Editor:Irreversible electroporation (IRE) is a CE- and FDA- approved treatment modality for pancreatic and liver tumors that is based on the site-confined destruction of tumor tissue by multiple short, high-... To the Editor:Irreversible electroporation (IRE) is a CE- and FDA- approved treatment modality for pancreatic and liver tumors that is based on the site-confined destruction of tumor tissue by multiple short, high-intensity electrical pulses. 展开更多
关键词 Potential therapeutic benefits stemming from the thermal nature of irreversible electropora tion of solid cancers
下载PDF
INFRARED DETECTOR USING SUPERCONDUCTING YBa_2Cu_3O_7-δTHIN FILMS
12
作者 WU Youyu YI XinjianWuhan Automotive Polytechnic UniversityHuazhong University of Science and Technology 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 1999年第4期40-47,共8页
The patterning technologies and process order of high Tc(86K) super-conducting film bolometers have been studied. After the deposition, a conventional lithographic process was used to pattern the films with aqueous so... The patterning technologies and process order of high Tc(86K) super-conducting film bolometers have been studied. After the deposition, a conventional lithographic process was used to pattern the films with aqueous solution of HCl, and then the films were transferred into a tube furnace for annealing to form superconducting film. It eliminates the degradation of patterning process. The bolometric responsivity of approximately 34. 32 V/W is measured, and the detectivity is greater than 1. 62× 108cm · Hz1/2 · W-1, the noise equivalent powers NEP is 2. 1×10-9W. 展开更多
关键词 BOLOMETER PATTERNING etching solu- tion YBa_2Cu_3O_7 δ superconducting films
下载PDF
Opening Remarks for the Seminar “Sino-Japanese Business Coopera tion on Environmental Protection”
13
作者 Liu Kaiyang Zhao Tianming 《International Understanding》 2013年第4期46-47,共2页
Distinguished Mr Yamada,President of the Council of Kazankai Foundation,Distinguished delegates:First of all,on behalf of the Chinese Association for International Understanding(CAFIU),I would like to extend my warm c... Distinguished Mr Yamada,President of the Council of Kazankai Foundation,Distinguished delegates:First of all,on behalf of the Chinese Association for International Understanding(CAFIU),I would like to extend my warm congratulations to the opening of the seminar.The exchange between CAFIU and 展开更多
关键词 Sino-Japanese Business Coopera tion on Environmental Protection Opening Remarks for the Seminar
下载PDF
SICK:特殊版安全光幕deTec Core HG
14
《今日制造与升级》 2018年第8期58-58,共1页
SICK特殊版安全光幕deTec Core HG拥有抵抗化学侵蚀的加强玻璃前镜凭借高抗腐蚀性,该产品可以完美地应用于恶劣环境中。deTec Core HG不仅提供高稳定性,更为工作在这些环境中的人员提供了高等级的安全防护。特性:加强型玻璃前镜,抗腐蚀;
关键词 安全光幕 detec Core HG
下载PDF
QTL×Environment interac tion for rice panicle charac teristics
15
《Chinese Rice Research Newsletter》 2001年第4期3-4,共2页
关键词 Environment interac tion for rice panicle charac teristics QTL
下载PDF
Staining for p53 and Ki-67 increases the sensitivity of EUS-FNA to detect pancreatic malignancy 被引量:3
16
作者 Alexander W Jahng Sonya Reicher +9 位作者 David Chung Donna Varela Rahul Chhablani Anil Dev Binh Pham Jose Nieto Rose J Venegas Samuel W French Bruce E Stabile Viktor E Eysselein 《World Journal of Gastrointestinal Endoscopy》 CAS 2010年第11期362-368,共7页
AIM:To investigate whether tumor marker staining can improve the sensitivity of endoscopic ultrasound-guided fine needle aspiration(EUS-FNA)to diagnose pancreatic malignancy. METHODS:Patients who underwent EUS-FNA wer... AIM:To investigate whether tumor marker staining can improve the sensitivity of endoscopic ultrasound-guided fine needle aspiration(EUS-FNA)to diagnose pancreatic malignancy. METHODS:Patients who underwent EUS-FNA were retrospectively identified.Each EUS-FNA specimen was evaluated by routine cytology and stained for tumor markers p53,Ki-67,carcinoembryonic antigen(CEA) and CA19-9.Sensitivity,specificity,positive and negative predictive values(PPV and NPV),and positive and negative likelihood ratios(PLR and NLR)were calculated in order to evaluate the performance of each test to detect malignancy. RESULTS:Sixty-one specimens had complete sets of stains,yielding 49 and 12 specimens from pancreatic adenocarcinomas and benign pancreatic lesions due to pancreatitis,respectively.Cytology alone had sensitivity and specificity of 41%and 100%to detect malignancy, respectively.In 46%of the specimens,routine cytology alone was deemed indeterminate.The addition of either p53 or Ki-67 increased the sensitivity to 51%and 53%,respectively,with perfect specificity,PPV and PLR (100%,100%and infinite).Both stains in combination increased the sensitivity to 57%.While additional staining with CEA and CA19-9 further increased the sensitivity to 86%,the specificity,PPV and PLR were significantly reduced(at minimum 42%,84%and 1,respectively).Markers in all combinations performed poorly as a negative test(NPV 26%to 47%,and NLR 0.27 and 0.70).CONCLUSION:Immunohistochemical staining for p53 and Ki-67 can improve the sensitivity of EUS-FNA to diagnose pancreatic adenocarcinoma. 展开更多
关键词 Endoscopic ultrasound Fine needle aspira tion PANCREATIC cancer P53 KI-67 IMMUNOHISTOCHEMISTRY
下载PDF
Use of Azotobacter sp.as an indicator to detect the toxicity of heavy metals in soils 被引量:2
17
作者 Liao Ruizhang, Shen Qiuqin, Jin Lizhi, Shen Shuling, Qian Houyin and Guan ZhenshengInstitute of Soils and Fertilizers,Chinese Academy of Agricultural Sciences,Beijing,China 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 1990年第3期123-128,共6页
A physiological strain of microorganism - Azotobacter sp. has been adopted as an indicator to detect the toxicity of heavy metals in soils. The concentration of heavy metals to which Azotobacter sp. was behaving initi... A physiological strain of microorganism - Azotobacter sp. has been adopted as an indicator to detect the toxicity of heavy metals in soils. The concentration of heavy metals to which Azotobacter sp. was behaving initially to have the resistance to heavy metals is defined as the critical poisoning concentration. The method of physiological threshold adopted can have a quantitative determination with reproducible results. The determined critical poisoning concentration is basically consistent with the results of heavy metals and arsenic toxicities to the bacteria reported recently in literatures. Total 9 typical soils, including 6 zonal soils and 3 purple soils, in the whole country were determined for the toxicities of 5 heavy metals and arsenic to Azotobacter sp. that resulted in 48 critical poisoning concentrations. 展开更多
关键词 soil microorganisms azotobacter sp heavy metals poisoning concentra-tion.
下载PDF
Morphological neural networks for automatic target detection by simulated annealing learning algorithm 被引量:7
18
作者 余农 吴昊 +2 位作者 吴常泳 李范鸣 吴立德 《Science in China(Series F)》 2003年第4期262-278,共17页
A practical neural network model for morphological filtering and a simulated annealing optimal algorithm for the network parameters training are proposed in this paper. It is pointed out that the opti- mal designing p... A practical neural network model for morphological filtering and a simulated annealing optimal algorithm for the network parameters training are proposed in this paper. It is pointed out that the opti- mal designing process of the morphological filtering network in fact is the optimal learning process of adjusting network parameters (structuring element, or SE for short) to accommodate image environment. Then the network structure may possess the characteristics of image targets, and so give specific infor- mation to the SE. Morphological filters formed in this way become certainly intelligent and can provide good filtering results and robust adaptability to complex changing image. For application to motional image target detection, dynamic training algorithm is applied to the designing process using asymptotic shrinking error and appropriate network weights adjusting. Experimental results show that the algorithm has invariant property with respect to shift, scale and rotation of moving target in continuing detection of moving targets. 展开更多
关键词 mathematical morphology image analyzing target detection neural network optimal calcula- tion.
原文传递
Handheld Aptasensor for Sandwiched Detection of Chloramphenicol
19
作者 YU Mintong XIA Tian +7 位作者 BAI Wanchen JI jinyu WANG Huan HUANG Yaqi DENG Shengyuan MA Kefeng SU Yan WAN Ying 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2020年第2期291-295,共5页
Chloramphenicol(CAP)is an antifungal agent approved for use in aquarium.However,CAP residue imparts serious adverse effect on human health as well as the ecology.Thus,keeping track of CAP in aquatic products and its e... Chloramphenicol(CAP)is an antifungal agent approved for use in aquarium.However,CAP residue imparts serious adverse effect on human health as well as the ecology.Thus,keeping track of CAP in aquatic products and its environmental metabolites are of great importance.Herein,we developed a novel and neat electrochemical aptasensor for the detection of simulated CAP residual in a sandwich fashion.The screen-printed carbon electrode was employed as the sensing platform and electrodeposited with peculiar nanogolds to enhance the electrochemical performance.For the specific recognition of such small target,a pair of chloramphenicol-binding aptamers,the primary Aptl and the secondary Apt2,were tailored as an artificial single-chained antibody couple,of which the thi-olated Aptl stood on the coated working substrate to capture the analyte,while the biotinylated Apt2 rallied the signal output.In the presence of CAP,Aptl at the lower place cooperated with the upper Apt2 pinched CAP together.After that,the reporter avidin-conjugated horseradish peroxidase associated atop the mounted biotin labels,resulting in an electrocatalytic amplification.In whole,this modular biosensing construction would set a paradigm not just for practicable checkpoint quarantine or point-of-care testing,but potentially adaptable for technological fusion with“Internet Plus”and“Internet of Things”. 展开更多
关键词 CHLORAMPHENICOL Screen-printed CARBON ELECTRODE ELECTROCHEMICAL APTASENSOR ELECTROCHEMICAL deposi tion Ufkimm
原文传递
基于双层聚类信息的极光亚暴自动检测
20
作者 王平 韩冰 +4 位作者 李洁 胡泽骏 尚军亮 葛道辉 袁玉卓 《极地研究》 CAS CSCD 北大核心 2024年第1期52-69,共18页
极光亚暴与太阳风和地球磁场的耦合过程有着紧密的联系,对其发生和发展机制的研究,有助于深入地分析行星际磁场、地球磁层和地球电离层的相互作用,了解太阳风携带的大量能量在地球空间的输运过程,对地球空间环境预警具有重要的意义。Po... 极光亚暴与太阳风和地球磁场的耦合过程有着紧密的联系,对其发生和发展机制的研究,有助于深入地分析行星际磁场、地球磁层和地球电离层的相互作用,了解太阳风携带的大量能量在地球空间的输运过程,对地球空间环境预警具有重要的意义。Polar卫星搭载的紫外极光图像成像仪能够全天候地获取紫外极光图像,在紫外极光图像中可以完整地展示出极区极光的亮度和尺度变化,尤其是可以清晰地展示出亚暴膨胀相的极光点亮和亮斑膨胀现象。现有的极光亚暴事件检测方法通常需要人工设计特征和相关规则库,耗时耗力。本文利用紫外极光图像提出了基于双层聚类信息的亚暴事件检测方法,实现了紫外极光图像数据中的亚暴事件自动检测。同时,针对极光亚暴事件检测依赖手工设计特征,设计了子空间聚类指导的三维卷积特征自动提取网络;针对极光图像帧间存在成像角度差异,利用地磁纬度和磁地方时信息对极光序列中图像的空间位置进行校正;针对卫星成像位置变化导致的成像噪声,利用极光图像级聚类保留极光亮斑区域和剔除未成像或噪声区域。主观和客观实验结果表明,本算法提升了亚暴事件检测的查全率。 展开更多
关键词 极光亚暴 双层聚类信息 三维卷积网络 自动检测
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部