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Algorithm Development of Cloud Removal from Solar Images Based on Pix2Pix Network

Computers, Materials & Continua 2022年第5期71卷 3497-3512页

作者： Xian Wu Wei Song Xukun Zhang Ganghua Lin haimin wang Yuanyong Deng School of Information Engineering Minzu University of ChinaBeijing100081China Key Laboratory of Solar Activity Chinese Academy of Sciences(KLSACAS)Beijing100101China National Language Resource Monitoring and Research Center of Minority Languages Minzu University of ChinaBeijing100081China National Astronomical Observatories Chinese Academy of Sciences(NAOCCAS)Beijing100101China Center for Solar-Terrestrial Research New Jersey Institute of TechnologyUniversity HeightsNewark07102-1982USA Institute for Space Weather Sciences New Jersey Institute of TechnologyUniversity HeightsNewark07102-1982USA Big Bear Solar Observatory New Jersey Institute of Technology40386North Shore LaneBig Bear City92314-9672USA

Sky clouds affect solar observations *** shadows obscure the details of solar features in observed ***-covered solar images are difficult to be used for further research without *** this paper,the solar image cloud removing problem is converted to an image-to-image translation problem,with a used algorithm of the Pixel to Pixel Network(Pix2Pix),which generates a cloudless solar image without relying on the physical scattering ***2Pix is consists of a generator and a *** generator is a well-designed *** discriminator uses PatchGAN structure to improve the details of the generated solar image,which guides the generator to create a pseudo realistic solar *** image generation model and the training process are optimized,and the generator is jointly trained with the *** the generation model which can stably generate cloudless solar image is *** experiment results on Huairou Solar Observing Station,National Astronomical Observatories,and Chinese Academy of Sciences(HSOS,NAOC and CAS)datasets show that Pix2Pix is superior to the traditional methods based on physical prior knowledge in peak signal-to-noise ratio,structural similarity,perceptual index,and subjective visual *** result of the PSNR,SSIM and PI are 27.2121 dB,0.8601 and 3.3341.

关键词： Pix2Pix solar image cloud removal

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Structure and evolution of magnetic fields associated with solar eruptions

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Research in Astronomy and Astrophysics 2015年第2期15卷 145-174页

作者： haimin wang Chang Liu Space Weather Research Laboratory and Big Bear Solar Observatory New Jersey Institute of Technology University Heights

This paper reviews the studies of solar photospheric magnetic field evo- lution in active regions and its relationship to solar flares. It is divided into two top- ics, the magnetic structure and evolution leading to solar eruptions and rapid changes in the photospheric magnetic field associated with eruptions. For the first topic, we describe the magnetic complexity, new flux emergence, flux cancelation, shear mo- tions, sunspot rotation and magnetic helicity injection, which may all contribute to the storage and buildup of energy that trigger solar eruptions. For the second topic, we concentrate on the observations of rapid and irreversible changes of the photospheric magnetic field associated with flares, and the implication on the restructuring of the three-dimensional magnetic field. In particular, we emphasize the recent advances in observations of the photospheric magnetic field, as state-of-the-art observing facilities （such as Hinode and Solar Dynamics Observatory） have become available. The link- ages between observations, theories and future prospectives in this research area are also discussed.

关键词： Sun:flares—Sun:magnetic fields

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The Energetics of White-light Flares Observed by SDO/HMI and RHESSI

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Research in Astronomy and Astrophysics 2016年第11期16卷 99-104页

作者： Neng-Yi Huang Yan Xu haimin wang Center for Solar-Terrestrial Research New Jersey Institute of Technology Newark NJ 07102-1982 USA Big Bear Solar Observatory Big Bear City CA 92314 USA

White-light （WL） flares have been observed and studied for more than a century since their first discovery. However, some fundamental physics behind the brilliant emission remains highly controversial. One of the important facts in addressing the flare energetics is the spatio-temporal correlation between the WL emission and the hard X-ray （HXR） radiation, presumably suggesting that energetic electrons are the energy sources. In this study, we present a statistical analysis of 25 strong flares （〉M5） observed simultaneously by the Helioseismic and Magnetic Imager （HMI）, on board the Solar Dynamics Observatory （SDO）, and the Reuven Ramaty High Energy Solar Spectroscopic lmager （RHESS1）. Among these events, WL emission was detected by SDO/HMI in 13 flares, associated with HXR emission. To quantitatively describe the strength of WL emission, equivalent area （EA） is defined as the integrated contrast enhancement over the entire flaring area. Our results show that the EA is inversely proportional to the HXR power-law index, indicating that stronger WL emission tends to be associated with a larger population of high energy electrons. However, no obvious correlation is found between WL emission and flux of non-thermal electrons at 50 keV. For the other group of 13 flares without detectable WL emission, the HXR spectra are softer （larger power-law index） than those flares with WL emission, especially for the X-class flares in this group.

关键词： Sun: flares - Sun: white-light - Sun: hard X-ray

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Irreversible rapid changes of magnetic field associated with the 2012 October 23 circular near-limb X1.8 Flare

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Research in Astronomy and Astrophysics 2016年第6期16卷 99-104页

作者： Dan-Dan Ye Chang Liu haimin wang Space Weather Research Laboratory and Big Bear Solar Observatory New Jersey Institute of TechnologyUniversity Heights

It has been found that photospheric magnetic fields can change in accordance with restructuring of the three-dimensional magnetic field following solar eruptions. Previous studies mainly use vector mag- netic field data taken for events near the disk center. In this paper, we analyze the magnetic field evolution associated with the 2012 October 23 X1.8 flare in NOAA AR 11598 that is close to the solar limb, using both the 45 s cadence line-of-sight and 12 min cadence vector magnetograms from the Helioseismic and Magnetic Imager on board Solar Dynamics Observatory. This flare is classified as a circular-ribbon flare with spine-fan type magnetic topology containing a null point. In the line-of-sight magnetograms, there are two apparent polarity inversion lines （PILs）. The PIL closer to the limb is affected more by the projection effect. Between these two PILs there lie positive polarity magnetic fields, which are surrounded by negative polarity fields outside the PILs. We find that after the flare, both the apparent limb-ward and disk-ward negative fluxes decrease, while the positive flux in-between increases. We also find that the horizontal mag- netic fields have a significant increase along the disk-ward PIL, but in the surrounding area, they decrease. Synthesizing the observed field changes, we conclude that the magnetic fields collapse toward the surface above the disk-ward PIL as depicted in the coronal implosion scenario, while the peripheral field turns to a more vertical configuration after the flare. We also suggest that this event is an asymmetric circular-ribbon flare： a flux rope is likely present above the disk-ward PIL. Its eruption causes instability of the entire fan-spine structure and the implosion near that PIL.

关键词： Sun flares -- Sun magnetic field

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The change of magnetic inclination angles associated with the X3.4 flare on December 13,2006

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Science China(Physics,Mechanics & Astronomy) 2009年第11期52卷 1702-1706页

作者： LI YiXuan JING Ju TAN ChangYi wang haimin Center for Solar-Terrestrial Research New Jersey Institute of TechnologyNewarkNJ 07102USA

Recent studies showed a consistent pattern of changes in the sunspot structure associated with major flares: part of the peripheral penumbral regions vanishes during flares, and meanwhile, the umbral cores and/or inner penumbral regions are darkened. To understand the underlying physics of these observations, we compare the magnetic inclination angle in the decayed peripheral and the enhanced inner penumbral regions before and after the 4B/X3.4 flare of 2006 December 13 by using the high-resolution vector magnetograms from Hinode. We find that the mean inclination angle in the decayed penumbra increases after the flare while that in the enhanced penumbra near flaring neutral line decreases. The result confirms the previous idea that two components of a δ sunspot become connected after flares. As a result of new connection, peripheral penumbral fields change from a more inclined to a more vertical configuration and transverse fields in umbral core and inner penumbral regions increase substantially (Liu et al. 2005). The flare-associated changes of Doppler width as well as other parameters (the transverse field strength, continuum intensity and filling factor) are also presented.

关键词： Sun:magnetic fields Sun:photosphere Sun:flares

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Heterostructure Cu_(3)P-Ni_(2)P/CP catalyst assembled membrane electrode for high-efficiency electrocatalytic nitrate to ammonia

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Nano Research 2024年第6期17卷 4872-4881页

作者： Meng Jin Jiafang Liu Xian Zhang Shengbo Zhang Wenyi Li Dianding Sun Yunxia Zhang Guozhong wang haimin Zhang Laboratory of Materials Physics Centre for Environmental and Energy NanomaterialsAnhui Key Laboratory of Nanomaterials and NanotechnologyCAS Center for Excellence in NanoscienceInstitute of Solid State PhysicsHefei Institutes of Physical ScienceChinese Academy of SciencesHefei 230031China University of Science and Technology of China Hefei 230026China Anhui Contango New Energy Technology Co. Ltd.Hefei 230031China

Electrochemical nitrate reduction reaction(NO_(3)RR)is a promising means for generating the energy carrier ***,we report the synthesis of heterostructure copper-nickel phosphide electrocatalysts via a simple vapor-phase hydrothermal *** resultant catalysts were evaluated for electrocatalytic nitrate reduction to ammonia(NH_(3))in three-type electrochemical *** detail,the regulation mechanism of the heterogeneous Cu_(3)P-Ni_(2)P/CP-x for NO_(3)RR performance was systematically studied through the H-type cell,rotating disk electrode setup,and membrane-electrode-assemblies(MEA)*** a result,the Cu_(3)P-Ni_(2)P/CP-0.5 displays the practicability in an MEA system with an anion exchange membrane,affording the largest ammonia yield rate(RNH_(3))of 1.9 mmol·h^(−1)·cm^(−2),exceeding most of the electrocatalytic nitrate reduction electrocatalysts reported to *** theoretical calculations and in-situ spectroscopy characterizations uncover that the formed heterointerface in Cu_(3)P-Ni_(2)P/CP is beneficial for promoting nitrate adsorption,activation,and conversion to ammonia through the successive hydrodeoxygenation pathway.

关键词： electrocatalytic nitrate reduction to ammonia three-type reactors membrane-electrode-assemblies system operando ATR-IRRAS successive hydrodeoxygenation pathway

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DeepSun:machine-learning-as-a-service for solar flare prediction

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Research in Astronomy and Astrophysics 2021年第7期21卷 51-61页

作者： Yasser Abduallah Jason T.L.wang Yang Nie Chang Liu haimin wang Institute for Space Weather Sciences New Jersey Institute of TechnologyUniversity HeightsNewarkNJ 07102-1982USA Department of Computer Science New Jersey Institute of TechnologyUniversity HeightsNewarkNJ 07102-1982USA Big Bear Solar Observatory New Jersey Institute of Technology40386 North Shore LaneBig Bear CityCA 92314-9672USA Center for Solar-Terrestrial Research New Jersey Institute of TechnologyUniversity HeightsNewarkNJ 07102-1982USA

Solar flare prediction plays an important role in understanding and forecasting space *** main goal of the Helioseismic and Magnetic Imager(HMI), one of the instruments on NASA's Solar Dynamics Observatory, is to study the origin of solar variability and characterize the Sun's magnetic *** provides continuous full-disk observations of the solar vector magnetic field with high cadence data that lead to reliable predictive capability;yet, solar flare prediction effort utilizing these data is still limited. In this paper, we present a machine-learning-as-a-service(MLaa S) framework, called Deep Sun,for predicting solar flares on the web based on HMI's data products. Specifically, we construct training data by utilizing the physical parameters provided by the Space-weather HMI Active Region Patch(SHARP)and categorize solar flares into four classes, namely B, C, M and X, according to the X-ray flare catalogs available at the National Centers for Environmental Information(NCEI). Thus, the solar flare prediction problem at hand is essentially a multi-class(i.e., four-class) classification problem. The Deep Sun system employs several machine learning algorithms to tackle this multi-class prediction problem and provides an application programming interface(API) for remote programming users. To our knowledge, Deep Sun is the first MLaa S tool capable of predicting solar flares through the internet.

关键词： Sun:flares Sun:activity methods:data analysis

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The correlation between expansion speed and magnetic field in solar flare ribbons

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Science China(Physics,Mechanics & Astronomy) 2009年第11期52卷 1754-1759页

作者： XIE WenBin wang haimin JING Ju BAO XingMing ZHANG HongQi Key Laboratory of Solar Activity National Astronomical Observatories of ChinaBeijing 100012China Physics Department New Jersey Institute of TechnologyNewarkNJ07102USA Jilin Normal University Jilin 136000China

In this paper, we study the correlation between the expansion speed of two-ribbon flares and the magnetic field measured in the ribbon location, and compare such correlation for two events with different magnetic configurations. These two events are: an M1.0 flare in the quiet sun on September 12, 2000 and an X2.3 flare in Active Region NOAA 9415 on April 10, 2001. The magnetic configuration of the M1.0 flare is simple, while that of X2.3 event is complex. We have derived a power-law correlation between the ribbon expansion speed (V r) and the longitudinal magnetic field (Bz) with an empirical relationship V r = A×Bz-δ, where A is a constant and δ is the index of the power-law correlation. We have found that δ for the M1.0 flare in the simple magnetic configuration is larger than that for the X2.3 flare in the complex magnetic configuration.

关键词： solar activity solar flares solar magnetic field

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Oxygen‑Coordinated Single Mn Sites for Efficient Electrocatalytic Nitrate Reduction to Ammonia

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Nano-Micro Letters 2024年第1期16卷 147-159页

作者： Shengbo Zhang Yuankang Zha Yixing Ye Ke Li Yue Lin Lirong Zheng Guozhong wang Yunxia Zhang Huajie Yin Tongfei Shi haimin Zhang Laboratory of Materials Physics Centre for Environmental and Energy NanomaterialsAnhui Key Laboratory of Nanomaterials and NanotechnologyCAS Center for Excellence in NanoscienceInstitute of Solid State PhysicsHFIPSChinese Academy of SciencesHefei 230031People’s Republic of China University of Science and Technology of China Hefei 230026People’s Republic of China Key Laboratory of Agricultural Sensors Ministry of AgricultureSchool of Information and ComputerAnhui Agricultural UniversityHefei 230026People’s Republic of China Hefei National Research Center for Physical Sciences at the Microscale University of Science and Technology of ChinaHefei 230026People’s Republic of China Beijing Synchrotron Radiation Facility Institute of High Energy PhysicsChinese Academy of Sciences19B Yuquan RoadBeijing 100049People’s Republic of China

Electrocatalytic nitrate reduction reaction has attracted increasing attention due to its goal of low carbon emission and environmental ***,we report an efficient NitRR catalyst composed of single Mn sites with atomically dispersed oxygen(O)coordination on bacterial cellulose-converted graphitic carbon(Mn-O-C).Evidence of the atomically dispersed Mn-(O-C_(2))_(4)moieties embedding in the exposed basal plane of carbon surface is confirmed by X-ray absorption *** a result,the as-synthesized Mn-O-C catalyst exhibits superior NitRR activity with an NH_(3)yield rate(RNH_(3))of 1476.9±62.6μg h^(−1)cm^(−2)at−0.7 V(*** hydrogen electrode,RHE)and a faradaic efficiency(FE)of 89.0±3.8%at−0.5 V(***)under ambient ***,when evaluated with a practical flow cell,Mn-O-C shows a high RNH_(3)of 3706.7±552.0μg h^(−1)cm^(−2)at a current density of 100 mA cm−2,2.5 times of that in the H *** in situ FT-IR and Raman spectroscopic studies combined with theoretical calculations indicate that the Mn-(O-C_(2))_(4)sites not only effectively inhibit the competitive hydrogen evolution reaction,but also greatly promote the adsorption and activation of nitrate(NO_(3)^(−)),thus boosting both the FE and selectivity of NH_(3)over Mn-(O-C_(2))_(4)sites.

关键词： Atomically dispersed Oxygen coordination Nitrate reduction reaction In situ spectroscopic studies Hydrogen evolution reaction

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Attack on an Efficient Certificateless Aggregate Signature without Pairing

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Wuhan University Journal of Natural Sciences 2020年第2期25卷 139-145页

作者： LI Huimin LIANG Hongmei wang haimin ZHANG Jinhui School of Mathematics and Finance Putian UniversityPutian 351100FujianChina Key Laboratory of Applied Mathematics Fujian Province University(Putian University)Putian 351100FujianChina School of Mathematics and Statistics Minnan Normal UniversityZhangzhou 363000FujianChina

A Certificateless Aggregate Signature(CLAS) scheme was proposed by Qu and Mu recently, which was published in "Int J. Electronic Security and Digital Forensics, 2018, 10(2)". They used discrete logarithm to ensure the scheme's security. However,we show by formulating an attack that their CLAS scheme cannot defend against Type I adversary. Furthermore, we point out an error that exists in the signature simulation of their security *** that we give a correct signature simulation for the security proof. Finally, to resist the Type I attack, we present two methods for improving Qu et al's CLAS scheme. Moreover, the second improving method can elevate the trust level of Qu et al's CLAS scheme to the highest trust level: Level 3.

关键词： certificateless aggregate signature attack security random oracle model discrete logarithm problem

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