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Photoelectron holography from multiple-return backscattering electron orbits

Physical Review A 2020年第2期101卷 023414-023414页

作者： ShaoGang Yu XuanYang Lai YanLan Wang SongPo Xu LinQiang Hua Wei Quan XiaoJun Liu State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics Wuhan Institute of Physics and Mathematics Innovation Academy for Precision Measurement Science and Technology Chinese Academy of Sciences Wuhan 430071 China University of Chinese Academy of Sciences Beijing 100049 China

We theoretically investigate the photoelectron momentum distributions of a diatomic molecule in a linearly polarized two-color laser field by solving the time-dependent Schrödinger equation. An upward curvature interference pattern is found in the two-dimensional photoelectron momentum spectra. Resorting to a simple semiclassical analysis and the strong-field approximation theory, we show that the interference pattern corresponds to a holographic pattern from the second-return backscattering electron orbits and, furthermore, the underlying physics of the distinct observation of such interference pattern is revealed. The holographic patterns from the backscattering electron orbits with the different return times may encode the information of the target structure at different times after ionization.

关键词： Multiphoton or tunneling ionization & excitation Strong-field approximation

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Probing atomic and nuclear properties with precision spectroscopy of fine and hyperfine structures in the Li+7 ion

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Physical Review A 2020年第3期102卷 030801(R)-030801(R)页

作者： Hua Guan Shaolong Chen Xiao-Qiu Qi Shiyong Liang Wei Sun Pengpeng Zhou Yao Huang Pei-Pei Zhang Zhen-Xiang Zhong Zong-Chao Yan G. W. F. Drake Ting-Yun Shi Kelin Gao State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics Wuhan Institute of Physics and Mathematics Innovation Academy for Precision Measurement Science and Technology Chinese Academy of Sciences Wuhan 430071 China University of Chinese Academy of Sciences Beijing 100049 China Department of Physics University of Windsor Windsor Ontario Canada N9B 3P4 Department of Physics University of New Brunswick Fredericton New Brunswick Canada E3B 5A3 Center for Cold Atom Physics Chinese Academy of Sciences Wuhan 430071 China

Precision spectroscopy of Li+ is a promising testing ground for bound-state quantum electrodynamics (QED) and for measurements of nuclear properties such as the Zemach radius. We investigate the hyperfine and fine-structure splittings of the 2S13 and 23PJ states of Li+7 using saturated fluorescence spectroscopy based on a ∼460eV metastable ion beam. We measure in particular the 2S13–2PJ3 transitions in Li+7. With a triple nested loop scanning method, the long-term drift and systematic uncertainties are reduced or eliminated, resulting in a total uncertainty of less than 100 kHz. Our results are in good agreement with QED calculations. For the hyperfine splittings of 2S13, our measured values have a similar accuracy to previous measurements and theoretical calculations. For the 23PJ fine and hyperfine splittings, our measured results are one order of magnitude more accurate than those of previous measurements and have a similar accuracy to the theoretical values. The measurements lay the foundation for future work on the Li+ isotopes and their theoretical interpretation in terms of nuclear charge radii and the Zemach radii.

关键词： Electronic structure of atoms & molecules Electronic transitions Fine & hyperfine structure Relativistic & quantum electrodynamic effects in atoms, molecules,& ions

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A GPU based single-pulse search pipeline (GSP) with database and its application to the commensal radio astronomy FAST survey (CRAFTS)

arXiv

引用

arXiv 2021年

作者： You, Shanping Wang, Pei Yu, Xuhong Xie, Xiaoyao Li, Di Liu, Zhijie Pan, Zhichen Yue, Youling Qian, Lei Zhang, Bin Chen, Zonghao School of Computer Science and Technology Guizhou University Guiyang550025 China Key Laboratory of Information and Computing Science Guizhou Province Guizhou Normal University Guiyang550001 China CAS Key Laboratory of FAST NAOC Chinese Academy of Sciences Beijing100101 China NAOC-UKZN Computational Astrophysics Centre University of KwaZulu-Natal Durban4000 South Africa

We developed a GPU based single-pulse search pipeline (GSP) with candidate-archiving database. Largely based upon the infrastructure of Open source pulsar search and analysis toolkit (PRESTO) ? (Ransom 2001), GSP implements GPU acceleration of the dedispersion and integrates a candidate-archiving database. We applied GSP to the data streams from the commensal radio astronomy FAST survey (CRAFTS), which resulted in a quasi-real-time processing. The integrated candidate database facilitates synergistic usage of multiple machine-learning tools and thus improves efficient identification of radio pulsars such as rotating radio transients (RRATs) and Fast Radio Bursts (FRBs). We first tested GSP on pilot CRAFTS observations with the FAST Ultra-Wide Band (UWB) receiver. GSP detected all pulsars known from the the Parkes multibeam pulsar survey in the respective sky area covered by the FAST-UWB. GSP also discovered 13 new pulsars. We measured the computational efficiency of GSP to be ∼120 times faster than the original PRESTO and ∼60 times faster than a MPI-parallelized version of PRESTO. Copyright © 2021, The Authors. All rights reserved.

关键词： Surveys

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The complete mitochondrial genome of an important medicinal plant,Rehmannia glutinosa(Gaertn.) DC., 1845 (Lamiales, Orobanchaceae)

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Mitochondrial DNA Part B 2025年第1期10卷

作者： Yu Bai Huan An Rengang Zhang Yanna Ma Hongjia Zhang Zhili Guo Li Zhao Zhaoxuan Wang a Shijiazhuang Medical College Shijiazhuang China b Shijiazhuang People’s Medical College Shijiazhuang China c Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Populations/State Key Laboratory of Plant Diversity and Specialty Crops Kunming Institute of Botany Chinese Academy of Sciences Kunming China d Bureau of Retired Officials of Huancui District Weihai China e National Key Laboratory of Non-food Biomass Energy Technology Nutrition and Health Research Institute China Oil Foodstuffs Corporation (COFCO) Beijing Chinaf College of Life Science and Technology Beijing University of Chemical Technology Beijing China g Department of Ecology and Environmental Science Umeå University Umeå Sweden

Rehmannia glutinosa, an extensively utilized Chinese herbal medicine, is highly valued for its medicinal properties. In this study, the complete mitochondrial genome (mitogenome) ofR. glutinosawas sequenced and assembled for the first time. The mitogenome is 547,032 bp in length, with an overall GC content of 44.97%. The mitogenome contains 67 unique genes, comprising 43 protein-coding, three rRNA, and 21 tRNA genes, with six protein-coding and nine tRNA genes being chloroplast-derived. The phylogenetic analysis, based on the maximum-likelihood criterion, demonstrated thatR. glutinosais closely related toAeginetia indicaandCastilleja paramensiswithin the family Orobanchaceae.

关键词： Mitogenome phylogeny Rehmannia glutinosa

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Complete mitochondrial genome ofParaisaria gracilioides(Hypocreales: Ophiocordycipitaceae) and phylogenetic analysis

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Mitochondrial DNA Part B 2025年第4期10卷

作者： Minghao Tang Wei Zheng Yixi Zhang Zihao Wang Wei Huang Qiaosun Huang Feifan Wang Yanan Wang Luodong Huang a College of Life Science and Technology Guangxi University Nanning China b State Key Laboratory for Quality Ensurance and Sustainable Use of Dao-Di Herbs National Resource Center for Chinese Materia Medica China Academy of Chinese Medical Sciences Beijing China

Paraisaria gracilioides(Kobayasi) Luangsa-ard, Mongkolsamrit & Samson, originally described asOphiocordyceps gracilioides, is a member of the Ophiocordycipitaceae, within the order Hypocreales. This study, presented the mitochondrial genome ofP. gracilioidesstructured as a circular molecule spanning 181,140 bp, was larger than those of most Ophiocordycipitaceae species. Despite this size variation, encoding 49 genes, including 15 PCGs, 26 tRNAs, two rRNAs, and six ORFs. Phylogenetic analysis based on nucleotide sequences of 14 PCGs revealed thatP. gracilioidesclustered withParaisaria gracilis, forming a subgroup withinOphiocordycepsspecies. The results contribute to refining the taxonomic framework of Ophiocordycipitaceae.

关键词： Paraisaria gracilioides Ophiocordycipitaceae mitochondrial genome phylogenetic analysis

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SemMT: A semantic-based testing approach for machine translation systems

arXiv

引用

arXiv 2020年

作者： Cao, Jialun Li, Meiziniu Li, Yeting Wen, Ming Cheung, Shing-Chi Chen, Haiming The Hong Kong University of Science and Technology Hong Kong State Key Laboratory of Computer Science Institute of Software Chinese Academy of Sciences University of Chinese Academy of Sciences Beijing China Huazhong University of Science and Technology Wuhan China

Machine translation has wide applications in daily life. In mission-critical applications such as translating official documents, incorrect translation can have unpleasant or sometimes catastrophic consequences. This motivates recent research on the testing methodologies for machine translation systems. Existing methodologies mostly rely on metamorphic relations designed at the textual level (e.g., Levenshtein distance) or syntactic level (e.g., distance between grammar structures) to determine the correctness of translation results. However, these metamorphic relations do not consider whether the original and the translated sentences have the same meaning (i.e., semantic similarity). To address this problem, in this paper, we propose SemMT, an automatic testing approach for machine translation systems based on semantic similarity checking. SemMT applies round-trip translation and measures the semantic similarity between the original and the translated sentences. Our insight is that the semantics concerning logical relations and quantifiers in sentences can be captured by regular expressions (or deterministic finite automata) where efficient semantic equivalence/similarity checking algorithms can be applied. Leveraging the insight, we propose three semantic similarity metrics and implement them in SemMT. We compared SemMT with related state-of-the-art testing techniques, demonstrating the effectiveness of mistranslation detection. The experiment results show that SemMT outperforms existing metrics, achieving an increase of 34.2% and 15.4% on accuracy and F-Score, respectively. We also study the possibility of further enhancing the performance by combining various metrics. Finally, we discuss a solution to locate the suspicious trip in round-trip translation, which provides hints for bug diagnosis. © 2020, CC BY.

关键词： Machine translation

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An Anomaly Pattern Detection Method for Sensor Data 16th

An Anomaly Pattern Detection Method for Sensor Data

引用

16th Web Information Systems and Applications Conference, WISA 2019

作者： Li, Han Yu, Bin Zhao, Ting College of Computer Science North China University of Technology Beijing China Beijing Key Laboratory on Integration and Analysis of Large-Scale Stream Data Beijing China Advanced Computing and Big Data Technology Laboratory of SGCC Global Energy Interconnection Research Institute Beijing China

ISBN: (纸本)9783030309510

With the development of the Internet of Things (IOT) technology, a large number of sensor data have been produced. Due to the complex acquisition environment and transmission condition, anomalies are prevalent. Sensor data is a kind of typical time series data, its anomaly refers to not only outliers, but also the anomaly of continuous data fragments, namely anomaly patterns. To achieve anomaly pattern detection on sensor data, the characteristics of sensor data are analyzed including temporal correlation, spatial correlation and high dimension. Then based on these characteristics and the real-time processing requirements of sensor data, a sensor data oriented anomaly pattern detection approach is proposed in this paper. In the approach, the frequency domain features of sensor data are obtained by Fast Fourier Transform, the dimension of the feature space is reduced by describing frequency domain features with statistical values, and the high-dimensional sensor data is processed in time on the basis of Isolation Forest algorithm. In order to verify the feasibility and effectiveness of the proposed approach, experiments are carried out on the open dataset IBRL. The experimental results show that the approach can effectively identify the pattern anomalies of sensor data, and has low time cost while ensuring the high accuracy. © 2019, Springer Nature Switzerland AG.

关键词： Fast Fourier transforms

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A novel algorithm of congestion control based on satellite switching 1

引用

4th International Conference on IoT as a Service, IoTaaS 2018

作者： Zhang, Yi Li, Jingling Li, Jun Cui, Tao Liang, Wei Li, Gong China Academy of Space Technology Xi’an71000 China National Key Laboratory of Science and Technology on Space Microwave Xi’an71000 China Beijing Institute of Space Mechanics and Electricity Beijing China

ISBN: (数字)9783030146573

ISBN: (纸本)9783030146566

. One of the characteristics of satellite switching network is limited link resources. When the satellite switching network is congested, there are not enough resources to send the congestion notification message to the ground terminal. In order to solve this problem, a novel algorithm of congestion control based on satellite switching is proposed in this paper. The congestion notification messages are sent while transmitting the switching data according to the specific hiding approach, which uses the redundant information in the switching data to embed the congestion control information into the transmission data. The method can send congestion control messages to the ground terminal without any additional physical resources, and also increase the amount of information that can be transmitted by each port of the onboard switch. The performance analysis and simulation result show that the proposed algorithm can not only avoid congestion in the onboard switch, but also save link resources and improve the performance of the satellite switching network. © ICST Institute for Computer sciences, Social Informatics and Telecommunications Engineering 2019.

关键词： Satellites

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A Service Selection Framework for Anomaly Detection in IoT Stream Data

A Service Selection Framework for Anomaly Detection in IoT S...

引用

International Conference on Service sciences (ICSS)

作者： Zhongguo Yang Weilong Ding Zhongmei Zhang Han Li Mingzhu Zhang Chen Liu School of Information Science and Technology Beijing Key Laboratory on Integration and Analysis of Large-Scale Stream Data North China University of Technology Beijing China School of Management Engineering Shandong Jianzhu University Jinan China

ISBN: (数字)9781728185316

ISBN: (纸本)9781728185323

Many anomaly detection algorithms have been provided as services for more convenient and efficient utilization in IoT era. Due to concept drift existed in dynamic IoT stream data, it is a changeling task to apply proper anomaly detection services at run time. For effective on-line anomalous data discovery, this paper proposes a service selection framework to dynamically select and configure anomaly detection services. A fast classification model based on XGBoost is trained to identify the pattern of various stream data, so that suitable service can be selected and configured according to the pattern of stream data. Extensive experiments on real and synthetic data sets show that our framework can select suitable service for different scenarios, and the accuracy of the chosen services outperforms state-of-the-art methods.

关键词： Image edge detection Heuristic algorithms Data models Pattern recognition Time complexity Task analysis Anomaly detection

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Lecture Information Service based on Multiple Features Fusion

Lecture Information Service based on Multiple Features Fusio...

引用

International Conference on Service sciences (ICSS)

作者： Zhongguo Yang Mingzhu Zhang Zhongmei Zhang Chen Liu Han Li Yuanyuan Lan School of Information Science and Technology Beijing Key Laboratory on Integration and Analysis of Large-Scale Stream Data North China University of Technology Beijing China School of Management Engineering Shandong Jianzhu University Jinan China

ISBN: (数字)9781728185316

ISBN: (纸本)9781728185323

Information service is always a hot topic especially when web is accessible anywhere. In university, lecture information is very import for students and teachers who want to take part in academic meetings. Therefore, lecture news extraction is an important and imperative task. Although many open information extraction methods have been proposed, but due to the highly heterogeneity of website, this task is still a challenge. In this manuscript, we propose a method based on fusing multiple features to locate lecture news in university web site. These features including the organization structure of lecture news catalog webpage, the visual similarity and the semantic of webpage. Additionally, this paper provide an information service based on a main content extraction algorithm for extracting lecture information. The stable and invariant features enable the propose method could adaptive to many kinds of campus website. The experiments conducted on 50 websites show the effectiveness and efficiencies of provided service.

关键词： Visualization Information services Web pages Feature extraction Data mining Web sites Task analysis

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