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5th IEEE International Power Modulator and High Voltage Conference (IPMHVC)

作者： Zhang, Cheng Shao, Tao Ren, Chengyan Yan, Ping Niu, Zongtao Chinese Acad Sci Inst Elect Engn Beijing Peoples R China Chinese Acad Sci Key Lab Power Elect & Elect Drive Beijing Peoples R China

ISBN: (纸本)9781509023547

In an inhomogeneous electric field, there are several kinds of discharge modes existing in microsecond-pulse gliding discharges. In this paper, we investigate mode transition among different discharge modes and the effects of pulse repetition frequency (PRF) and gap distance on microsecond-ppulse gliding discharge by measuring the voltage-current waveforms and discharge images. Experimental results showed that a diffuse discharge was obtained in atmospheric pressure in microsecond-pulse gliding discharge. When the applied voltage was 18.5 kV, diffuse-to-spark transition occurred when the PRF increased from 500 Hz to 2000 Hz. Furthermore, the diffuse discharge might appear when the electrode gap exceeded 5 mm. When the applied voltage was 12 kV, decreasing the gap spacing leaded to diffuse-to-spark transition. Therefore, both PRF and gap distance affect the discharge mode in microsecond-pulse gliding discharges. Diffuse-to-spark transition occurs when the PRF increases or the gap spacing decreases. It could provide reference for obtaining volume discharge at atmospheric pressure.

关键词： gliding discharge microsecond pulse atmospheric pressure diffuse mode spark mode

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Parallel Implementation ALS Collaborative Filtering Algorithm on Spark Cluster Platform

Parallel Implementation ALS Collaborative Filtering Algorith...

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2018 4th ICMSMA International Conference on Advances in Intelligent Information Technologies (ICAIIT 2018)

作者： Jing Wang Haibo Luo Guangdong Polytechnic Institute Neusoft of Institute

This document explains the principle of ALS collaborative filtering recommendation algorithm and depicts its parallel implementation on Spark cluster *** explore the effects for recommendation accuracy and time cost,comparison experiments are carried out in different MovieLens data *** results show the efficiency of parallel computing of ALS collaborative filtering algorithm on Spark cluster platform,which is more suitable for processing massive data.

关键词： ALS Collaborative filtering Matrix factorization Spark

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Influence of the AMF Arc Control on Voltage Distribution of Double-Break VCBs

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IEEE TRANSACTIONS ON PLASMA SCIENCE 2016年第10期44卷 2455-2461页

作者： Liao, Minfu Ge, Guowei Duan, Xiongying Huang, Jinqiang Huang, Zhihui Zou, Jiyan Dalian Univ Technol Dept Elect & Elect Engn Dalian 116023 Peoples R China

This paper investigates the influence of the axial magnetic field (AMF) arc control on voltage distribution (VD) of double-break vacuum circuit breakers (VCBs) in order to gain balanced VD, and thus enhance the breaking capacity. The interaction of vacuum arc plasma, postarc current (PAC), and AMF is discussed. We conduct the breaking test of double-break VCBs with externally applied AMF of a different pulsewidth, magnitude, and a different moment. The PAC, postarc charge, and the VD are measured to analyze the relationship between the AMF arc control and the VD. The optimal AMF arc control and the relationship between the AMF magnitude and the unbalanced voltage ratio are gained when the grading capacitors were 400 pF. The experimental test showed that the proper AMF arc control can improve the unbalanced VD. The mechanism is that the proper AMF arc control can make the postarc charge small and stable, so the unbalanced postarc charge, which caused the unbalanced VD is limited.

关键词： Axial magnetic field (AMF) postarc current (PAC) vacuum switches voltage distribution (VD)

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HADAMARD Transform Sample Matrix Used in Compressed Sensing Super-Resolution Imaging 1

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10th International Conference on Intelligent Robotics and Applications (ICIRA

作者： Ye, Mei Ye, Hunian Yan, Guangwei Huazhong Univ Sci & Technol 1037 Luoyu Rd Wuhan Peoples R China

ISBN: (数字)9783319652986

ISBN: (纸本)9783319652986;9783319652979

To realize super-resolution optical and terahertz imaging by the sub-wavelength hole arrays with extraordinary optical transmission (EOT) performance, the related sampling template structure is studied. In this paper, Hadamard matrix, cyclic S matrix and matrix chosen by random matrix selector are defined as a small probability matrix. The sub-wavelength coding imaging template based on the structure of this small probability matrix have extraordinary optical transmission (EOT) performance, which is the basis for achieving super-resolution imaging. It is showed that, in the case of array detector, high signal-to-noise ratio (SNR) improvement (exceeded 22) can be obtained only by sampling one frame using the imaging template designed by 3 order cyclic S matrix. For single detector, the SNR improvement using various order of cyclic S matrix designed imaging template is higher than N a quadratic root obtained by Hadamard matrix in classical Hadamard transform optical imaging method, and much higher than half a quadratic root of N by classical cyclic S matrix.

关键词： Compressed sensing Hadamard transform Imaging Sampling template

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Bio-inspired Murray materials for mass transfer and activity

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NATURE COMMUNICATIONS 2017年第1期8卷 14921-14929页

作者： Zheng, Xianfeng Shen, Guofang Wang, Chao Li, Yu Dunphy, Darren Hasan, Tawfique Brinker, C. Jeffrey Su, Bao-Lian Wuhan Univ Technol State Key Lab Adv Technol Mat Synth & Proc Loushi Rd 122 Wuhan 430070 Peoples R China Univ New Mexico Dept Chem & Nucl Engn NSF UNM Ctr Microengn Mat Albuquerque NM 87131 USA Univ Cambridge Dept Engn Cambridge Graphene Ctr Cambridge CB3 0FA England Sandia Natl Labs Adv Mat Lab 1001 Univ Blvd SE Albuquerque NM 87106 USA Univ Namur Dept Chem Lab Inorgan Mat Chem 61 Rue Bruxelles B-5000 Namur Belgium Univ Cambridge Clare HallHerschel Rd Cambridge CB3 9AL England Univ Queensland Sch Chem Engn Brisbane Qld 4072 Australia Univ Queensland AIBN Brisbane Qld 4072 Australia

Both plants and animals possess analogous tissues containing hierarchical networks of pores, with pore size ratios that have evolved to maximize mass transport and rates of reactions. The underlying physical principles of this optimized hierarchical design are embodied in Murray's law. However, we are yet to realize the benefit of mimicking nature's Murray networks in synthetic materials due to the challenges in fabricating vascularized structures. Here we emulate optimum natural systems following Murray's law using a bottom-up approach. Such bio-inspired materials, whose pore sizes decrease across multiple scales and finally terminate in size-invariant units like plant stems, leaf veins and vascular and respiratory systems provide hierarchical branching and precise diameter ratios for connecting multi-scale pores from macro to micro levels. Our Murray material mimics enable highly enhanced mass exchange and transfer in liquid-solid, gas-solid and electrochemical reactions and exhibit enhanced performance in photocatalysis, gas sensing and as Li-ion battery electrodes.

关键词： Catalyst synthesis Porous materials Synthesis and processing

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iTRAQ-based proteomics analysis of hippocampus in spatial memory deficiency rats induced by simulated microgravity

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JOURNAL OF PROTEOMICS 2017年 160卷 64-73页

作者： Wang, Tingmei Chen, Hailong Lv, Ke Ji, Guohua Zhang, Yongliang Wang, Yanli Li, Yinghui Qu, Lina China Astronaut Res & Training Ctr State Key Lab Space Med Fundamentals & Applicat 26 Beiqing Rd Beijing 100094 Peoples R China Northwestern Polytech Univ Sch Life Sci Xian 710072 Peoples R China Space Inst Southern China Shenzhen Shenzhen 518117 Peoples R China

It has been demonstrated that simulated microgravity (SM) may lead to cognitive dysfunction. However, the underlying mechanism remains unclear. In present study, tail-suspension (30 degrees) rat was employed to explore the effects of 28 days of SM on hippocampus-dependent learning and memory capability and the underlying mechanisms. We found that 28-day tail-suspension rats displayed decline of learning and memory ability in Morris water maze (MWM) test. Using iTRAQ-based proteomics analysis, a total of 4774 proteins were quantified in hippocampus. Of these identified proteins, 147 proteins were differentially expressed between tail-suspension and control group. Further analysis showed these differentially expressed proteins (DEPs) involved in different molecular function categories, and participated in many biological processes. Based on the results of PANTHER pathway analysis and further western blot verification, we observed the expression of glutamate receptor 1 (GluR1) and glutamate receptor 4 (GluR4) which involved in metabotropic glutamate receptor group III pathway and ionotropic glutamate receptor pathway were significantly induced by SM. Moreover, an increased concentration of glutamic acid (Glu) was also found in hippocampus while the concentrations of 5-hydroxytryptamine (5-HT), dopamine (DA), gamma-amino acid butyric acid (GABA) and epinephrine (E) were decreased. Our finding confirms that 28-day SM exposure can cause degrading of the spatial learning and memory capability and the possible mechanisms might be related with glutamate excitotoxicity and imbalances in specific neurotransmitters. Biological significance: The goal of sending astronauts farther into space and extending the duration of spaceflight missions from months to years will challenge the current capabilities of bioastronautics. The investigation of the physiological and pathological changes induced by spaceflight will be critical in developing countermeasures to ensure astronauts to com

关键词： Simulated microgravity iTRAQ Cognitive dysfunction Hippocampus Excitotoxicity

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The Design of Post Arc Current Measurement System with High Precision on Multi-break Vacuum Circuit Breakers 4

The Design of Post Arc Current Measurement System with High ...

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4th International Conference on Electric Power Equipment-Switching technology (ICEPE-ST)

作者： Liao, Minfu Zhang, Hao Duan, Xiongying Zou, Jiyan Dong, Enyuan Ge, Guowei Dalian Univ Technol Sch Elect Engn Dalian Peoples R China Zhengzhou Univ Sch Elect Engn Zhengzhou Henan Peoples R China

ISBN: (纸本)9781538616512

A set of post arc current measurement system with high precision on multi-break vacuum circuit breakers(VCBs) was designed, and factors affecting the precision were analyzed. The improved shunt in current measurement showed high accuracy and fast response speed, so it could satisfy the demand of the precision. Meanwhile, with the changing of structure, the problems which were caused by surface action and producing heat were availably solved. In addition, the data acquisition system with optical fiber isolation was used to connect with measurement system. The superiority of post arc current measurement system with high precision in multi-break VCBs was confirmed by simulating in Ansys Maxwell and making experiments. Built simulating model in Ansys Maxwell, and simulated the electric field and thermal field of the shunt. The current measurement system could measure post arc current effectively which was proved. This could provide an effect method to study vacuum arc in Multi-break Vacuum Circuit Breakers.

关键词： Post Arc Current Measurement System Multi-break Vacuum Circuit Breakers High Precision Improved Shunt

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First Sagittarius A* Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole in the Center of the Milky Way

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ASTROPHYSICAL JOURNAL LETTERS 2022年第2期930卷 L12-L12页

作者： Akiyama, Kazunori Alberdi, Antxon Alef, Walter Algaba, Juan Carlos Anantua, Richard Asada, Keiichi Azulay, Rebecca Bach, Uwe Baczko, Anne-Kathrin Ball, David Balokovic, Mislav Barrett, John Baubock, Michi Benson, Bradford A. Bintley, Dan Blackburn, Lindy Blundell, Raymond Bouman, Katherine L. Bower, Geoffrey C. Boyce, Hope Bremer, Michael Brinkerink, Christiaan D. Brissenden, Roger Britzen, Silke Broderick, Avery E. Broguiere, Dominique Bronzwaer, Thomas Bustamante, Sandra Byun, Do-Young Carlstrom, John E. Ceccobello, Chiara Chael, Andrew Chan, Chi-kwan Chatterjee, Koushik Chatterjee, Shami Chen, Ming-Tang Chen, Yongjun Cheng, Xiaopeng Cho, Ilje Christian, Pierre Conroy, Nicholas S. Conway, John E. Cordes, James M. Crawford, Thomas M. Crew, Geoffrey B. Cruz-Osorio, Alejandro Cui, Yuzhu Davelaar, Jordy De Laurentis, Mariafelicia Deane, Roger Dempsey, Jessica Desvignes, Gregory Dexter, Jason Dhruv, Vedant Doeleman, Sheperd S. Dougal, Sean Dzib, Sergio A. Eatough, Ralph P. Emami, Razieh Falcke, Heino Farah, Joseph Fish, Vincent L. Fomalont, Ed Ford, H. Alyson Fraga-Encinas, Raquel Freeman, William T. Friberg, Per Fromm, Christian M. Fuentes, Antonio Galison, Peter Gammie, Charles F. Garcia, Roberto Gentaz, Olivier Georgiev, Boris Goddi, Ciriaco Gold, Roman Gomez-Ruiz, Arturo, I Gomez, Jose L. Gu, Minfeng Gurwell, Mark Hada, Kazuhiro Haggard, Daryl Haworth, Kari Hecht, Michael H. Hesper, Ronald Heumann, Dirk Ho, Luis C. Ho, Paul Honma, Mareki Huang, Chih-Wei L. Huang, Lei Hughes, David H. Ikeda, Shiro Impellizzeri, C. M. Violette Inoue, Makoto Issaoun, Sara James, David J. Jannuzi, Buell T. Janssen, Michael Jeter, Britton Jiang, Wu Jimenez-Rosales, Alejandra Johnson, Michael D. Jorstad, Svetlana Joshi, Abhishek, V Jung, Taehyun Karami, Mansour Karuppusamy, Ramesh Kawashima, Tomohisa Keating, Garrett K. Kettenis, Mark Kim, Dong-Jin Kim, Jae-Young Kim, Jongsoo Kim, Junhan Kino, Motoki Koay, Jun Yi Kocherlakota, Prashant Kofuji, Yutaro Koch, Patrick M. Koyama, Shoko Kramer, Carsten Kramer, Michael Krichbaum, Thomas P. K MIT Haystack Observ 99 Millstone Rd Westford MA 01886 USA Natl Astron Observ Japan 2-21-1 Osawa Mitaka Tokyo 1818588 Japan Harvard Univ Black Hole Initiat 20 Garden St Cambridge MA 02138 USA CSIC Inst Astrofis Andalucia Glorieta Astron S-N E-18008 Granada Spain Max Planck Inst Radioastron Hugel 69 D-53121 Bonn Germany Univ Malaya Fac Sci Dept Phys Kuala Lumpur 50603 Malaysia Ctr Astrophys Harvard & Smithsonian 60 Garden St Cambridge MA 02138 USA Univ Texas San Antonio Dept Phys & Astron One UTSA Circle San Antonio TX 78249 USA Acad Sinica Inst Astron & Astrophys 11F Astron Math BldgAS NTU 1Sec 4Roosevelt Rd Taipei 10617 Taiwan Univ Valencia Dept Astron & Astrofis C Dr Moliner 50 E-46100 Valencia Spain Univ Valencia Observ Astron C Catedrat Jose Beltran 2 E-46980 Valencia Spain Univ Arizona Steward Observ 933 N Cherry Ave Tucson AZ 85721 USA Univ Arizona Dept Astron 933 N Cherry Ave Tucson AZ 85721 USA Yale Univ Yale Ctr Astron & Astrophys 52 Hillhouse Ave New Haven CT 06511 USA Univ Illinois Dept Phys 1110 West Green St Urbana IL 61801 USA Fermilab Natl Accelerator Lab MS209POB 500 Batavia IL 60510 USA Univ Chicago Dept Astron & Astrophys 5640 South Ellis Ave Chicago IL 60637 USA East Asian Observ 660 N Aohoku Pl Hilo HI 96720 USA James Clerk Maxwell Telescope JCMT 660 N Aohoku Pl Hilo HI 96720 USA CALTECH 1200 East Calif Blvd Pasadena CA 91125 USA Acad Sinica Inst Astron & Astrophys 645 N Aohoku Pl Hilo HI 96720 USA Univ Hawaii Manoa Dept Phys & Astron 2505 Correa Rd Honolulu HI 96822 USA McGill Univ Dept Phys 3600 Rue Univ Montreal PQ H3A 2T8 Canada McGill Univ McGill Space Inst 3550 Rue Univ Montreal PQ H3A 2A7 Canada Inst Radioastron Millimetr IRAM 300 Rue Piscine F-38406 St Martin Dheres France Radboud Univ Nijmegen Inst Math Astrophys & Particle Phys IMAPP Dept Astrophys POB 9010 NL-6500 GL Nijmegen Netherlands Perimeter Inst Theoret Phys 31 Caroline St N Waterloo ON N2L 2Y5 Canada Univ Waterloo Dept

We present the first Event Horizon Telescope (EHT) observations of Sagittarius A* (Sgr A*), the Galactic center source associated with a supermassive black hole. These observations were conducted in 2017 using a global interferometric array of eight telescopes operating at a wavelength of lambda = 1.3 mm. The EHT data resolve a compact emission region with intrahour variability. A variety of imaging and modeling analyses all support an image that is dominated by a bright, thick ring with a diameter of 51.8 +/- 2.3 mu as (68% credible interval). The ring has modest azimuthal brightness asymmetry and a comparatively dim interior. Using a large suite of numerical simulations, we demonstrate that the EHT images of Sgr A* are consistent with the expected appearance of a Kerr black hole with mass similar to 4 x 10(6) M (circle dot), which is inferred to exist at this location based on previous infrared observations of individual stellar orbits, as well as maser proper-motion studies. Our model comparisons disfavor scenarios where the black hole is viewed at high inclination (i > 50 degrees), as well as nonspinning black holes and those with retrograde accretion disks. Our results provide direct evidence for the presence of a supermassive black hole at the center of the Milky Way, and for the first time we connect the predictions from dynamical measurements of stellar orbits on scales of 10(3)-10(5) gravitational radii to event-horizon-scale images and variability. Furthermore, a comparison with the EHT results for the supermassive black hole M87* shows consistency with the predictions of general relativity spanning over three orders of magnitude in central mass.

关键词： Black holes Kerr black holes Rotating black holes Heterodyne interferometry Galactic center

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Reinforcements stimulated dynamic recrystallization behavior and tensile properties of extruded (TiB + TiC + La₂O₃)/Ti6Al4V composites

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JOURNAL OF ALLOYS AND COMPOUNDS 2017年 699卷 874-881页

作者： Qiu, Peikun Li, Hong Sun, Xianglong Han, Yuanfei Huang, Guangfa Lu, Weijie Zhang, Di Shanghai Jiao Tong Univ State Key Lab Met Matrix Composites Shanghai 200240 Peoples R China Northwestern Polytech Univ State Key Lab Solidificat Proc Xian 70072 Peoples R China

TiB, TiC and La2O3 multiple-reinforced Ti6Al4V matrix composites were successfully fabricated by common casting based on the in situ reaction of Ti, B4C, LaB6, and oxygen in the raw materials and forged subsequently. Hot extrusion was carried out on the as-forged composites to investigate its effect on microstructure and tensile properties of Ti6Al4V composites reinforced by low volume fraction of reinforcements. The microstructure showed that the TiBw and TiCp distributed homogeneously and the clustered reinforcements disappeared after hot extrusion. Besides, TiBw exhibited favorable alignment, rotating parallel to the extrusion direction and TiCp also distributed along the same direction. Moreover, the microstructure of as-extruded composites tended to formed two kind of microstructure zones: finer basket-weave zones containing few reinforcements, and equiaxial zones embedded with abundant reinforcements, which indicated that reinforcements stimulated dynamic recrystallization during hot extrusion. The tensile test results revealed that the hot extrusion can significantly improve the ductility of (TiB + TiC + La2O3)/Ti6Al4V composites accompanied by slight decrease of tensile strength, among which the 1.5 vol% (TiB + TiC + La2O3)/Ti6Al4V increased by nearly four times from 2.71% to 13.2% With ultimate strength decreasing by 8.5%. from 954 MPa to 903 MPa, compared with that of the as-forged composites. (C) 2017 Elsevier B.V. All rights reserved.

关键词： Hot extrusion Titanium matrix composites Dynamic recrystallization Tensile properties Ti6Al4V

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Interfacial assembly of ZnO-cellulose nanocomposite films via a solution process: a one-step biomimetic approach and excellent photocatalytic properties

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CELLULOSE 2017年第1期24卷 147-162页

作者： Fu, Feiya Gu, Jiayuan Xu, Xinyi Xiong, Qinxue Zhang, Yanyan Liu, Xiangdong Zhou, Jinping Zhejiang Sci Tech Univ Coll Mat & Text Dept Mat Engn Hangzhou 310018 Zhejiang Peoples R China Zhejiang Sci Tech Univ Minist Educ Key Lab Adv Text Mat & Mfg Technol Hangzhou 310018 Zhejiang Peoples R China Wuhan Univ Minist Educ Dept Chem Wuhan 430072 Peoples R China Wuhan Univ Key Lab Biomed Polymers Minist Educ Wuhan 430072 Peoples R China

A bioinspired mineralization route to directly prepare ZnO-cellulose nanocomposite (ZCN) films from a cellulose-NaOH/urea/zincate solution was demonstrated in this study. By adding non-acid coagulants, an inclusion complex consisting of NaOH, urea and zincate, which was bound to the cellulose molecules, was broken. As a result, the cellulose aggregates occurred, which simultaneously aided the mineralization of ZnO nanostructures at room temperature. The structure and properties of the ZCN films were characterized using FE-SEM, TEM, XRD, UV-Vis spectra, XPS, TG, tensile testing and photocatalytic activity tests. Through changing different coagulants, the content and mean size of ZnO in the ZCN films varied in the range of 10.8-14.9 wt% and 56.8-146.8 nm, respectively. Owing to good interfacial interaction, the ZCN films displayed good mechanical and excellent photocatalytic properties. The mechanical strength and elongation at break of the ZCN films attained 46.7 MPa and 6.4 %, respectively. The degradation efficiency of rhodamine B reached 99.3 % within 50 min under UV light and only showed a slight decrease after three cycles. The cellulose-mediated bioinspired approach was expected to introduce a method for preparing functional cellulose-based materials under mild conditions for various niche applications.

关键词： Bio-inspired mineralization Cellulose ZnO nanoparticles Nanocomposite film Photocatalysis

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