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The prediction method of similar cycles

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Research in Astronomy and Astrophysics 2011年第12期11卷 1482-1492页

作者： zhan.le Du Hua-Ning Wang Key Laboratory of Solar Activity National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China

The concept of degree of similarity （η）, is proposed to quantitatively describe the similarity of a parameter （e.g. the maximum amplitude Rmax） of a solar cycle relative to a referenced one, and the prediction method of similar cycles is further developed. For two parameters, the solar minimum （Rmin） and rising rate （βa）, which can be directly measured a few months after the minimum, a synthesis degree of similarity （ηs） is defined as the weighted-average of the η values around Rmin and βa, with the weights given by the coefficients of determination of Rmax with Rmin and βa, respectively. The monthly values of the whole referenced cycle can be predicted by averaging the corresponding values in the most similar cycles with the weights given by the ηs values. As an application, Cycle 24 is predicted to peak around January 2013 i8 （month） with a size of about Rmax = 84 ± 17 and to end around September 2019.

关键词： Sun: activity -- Sun: general -- sunspots

Does a low solar cycle minimum hint at a weak upcoming cycle?

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Research in Astronomy and Astrophysics 2010年第10期10卷 950-955页

作者： zhan.le Du Hua-Ning Wang Key Laboratory of Solar Activity National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China

The maximum amplitude （Rm） of a solar cycle, in the term of mean sunspot numbers, is well-known to be positively correlated with the preceding minimum （Rmin）. So far as the long term trend is concerned, a low level of Rmin tends to be followed by a weak Rm, and vice versa. We found that the evidence is insufficient to infer a very weak Cycle 24 from the very low Rmin in the preceding cycle. This is concluded by analyzing the correlation in the temporal variations of parameters for two successive cycles.

关键词： Sun activity -- Sun general -- sunspots

A substorm-associated enhancement in the XUV radiation measuring channel observed by ESP/EVE/SDO

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Research in Astronomy and Astrophysics 2016年第6期16卷 21-28页

作者： Yan Yan Hua-NingWang Chao Shen zhan.le Du National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China Key Laboratory of Solar Activity Chinese Academy of Sciences Beijing 100012 China School of Natural Sciences and Humanity Harbin Institute of Technology Shenzhen Graduate School Shenzhen518055 China University of Chinese Academy of Sciences Beijing 100049 China

Comparing the ESP/EVE/SDO flux data of 2011 Feb 6, with the counterparts of XRS/GOES and SEM/SOHO, we find that there is an enhancement that is not apparent in the two latter datasets. The enhancement, possibly regarded as a flare at first glimpse, nevertheless, does not involve an energy-release from the Sun. Based on the enhancement, we combine data from SXI/GOES 15 into a synthesized analysis, and concluded that it arises from a particle-associated enhancement in the channel that measures XUV radiation. Paradoxically, it seems to be somewhat of a particle-avalanching process. Prior to the event, a moderate geomagnetic storm took place. Subsequently, while the event is proceeding, a geomagnetic substorm is simultaneously observed. Therefore, the particles, though unidentified, are probably energetic electrons induced by substorm injection.

关键词： Sun: X-rays gamma rays -- Sun: flares -- Sun: solar-terrestrial relations

The Relation between the Amplitude and the Period of Solar Cycles

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Chinese Journal of Astronomy and Astrophysics 2006年第4期6卷 489-494页

作者： zhan.le Du Hua-Ning Wang Xiang-Tao He National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 Department of Astronomy Beijing Normal University Beijing 100875

The maximum amplitudes of solar activity cycles are found to be well anticorrelated （r = -0.72） with the newly defined solar cycle lengths three cycles before （at lag -3） in 13-month running mean sunspot numbers during the past 190 years. This result could be used for predicting the maximum sunspot numbers. The amplitudes of Cycles 24 and 25 are estimated to be 149.5±27.6 and 144.3±27.6, respectively.

关键词： Sun: activity -- Sun: sunspots -- Sun: general

A Running Average Method for Predicting the Size and length of a Solar Cycle

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Chinese Journal of Astronomy and Astrophysics 2008年第4期8卷 477-488页

作者： zhan.le Du Hua-Ning Wang Li-Yun zhan. National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China

The running correlation coefficient between the solar cycle amplitudes and the max-max cycle lengths at a given cycle lag is found to vary roughly in a cyclical wave with the cycle number, based on the smoothed monthly mean Group sunspot numbers available since 1610. A running average method is proposed to predict the size and length of a solar cycle by the use of the varying trend of the coefficients. It is found that, when a condition （that the correlation becomes stronger） is satisfied, the mean prediction error （16.1） is much smaller than when the condition is not satisfied （38.7）. This result can be explained by the fact that the prediction must fall on the regression line and increase the strength of the correlation. The method itself can also indicate whether the prediction is reasonable or not. To obtain a reasonable prediction, it is more important to search for a running correlation coefficient whose varying trend satisfies the proposed condition, and the result does not depend so much on the size of the correlation coefficient. As an application, the peak sunspot number of cycle 24 is estimated as 140.4 ± 15.7, and the peak as May 2012 ±11 months.

关键词： Sun activity -- Sun sunspots - Sun general

High-Energy Ions Emitted from Ar Clusters Irradiated by Intense Femtosecond Laser Pulses

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Chinese Physics letters 2000年第2期17卷 99-100页

作者： LI Zhong leI An-le NI Guo-Quan XU Zhi-zhan Laboratory for Hligh intensity Optics Shanghai Institute of Optics and Fine MechanicsChinese Academy of SciencesShanghai 201800 Laboratory for Quantum Optics Shanghai Institute of Optics and Fine MechanicsChinese Academy of SciencesShanghai 201800

We have experimentally studied the energy spectra of Ar ions emitted from Ar clusters irradiated by intense femtosecond laser pulses. The Ar clusters were produced in the adiabatic expansion of Ar gas into vacuum at high backing pressures. The laser peak intensity was about 2×106 W/cm2 with a pulse duration of 45 fs. The maximum and the average energies of Ar ions are 0.2 MeV and 15kev at a backing pressure of 2. S MPa, respectively. They are almost independent of the backing pressures in the range of 0.6 to 4.5 MPa.

关键词： Femto laser Pulse

Interface issues and challenges for NASICON-based solid-state sodium-metal batteries

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Advanced Powder Materials

Advanced Powder Materials 2024年第3期3卷 32-47页

作者： le Xiang Xiutao Li Jin Xiao Lingyun Zhu Xiaowen zhan School of Materials Science and Engineering School of Chemistry and Chemical EngineeringKey Laboratory of Structure and Functional Regulation of Hybrid Materials of Ministry of EducationAnhui UniversityHefei 230601China

All-solid-state sodium(Na)-metal batteries(ASSSMBs)are considered promising candidates for large-scale energy storage systems due to their abundant sodium resources,unparalleled safety performance,and impressive energy *** superionic conductors(NASICONs)are among the best enablers of ASSSMBs in view of their high ionic conductivity,ease of synthesis,and excellent thermal stability and good electrochemical/chemical compatibility with common ***,challenges surrounding the NASICON/electrode interface,such as high interfacial resistance and dendrite formation,have hindered the development of practical ASSSMBs based on *** review starts with an explicit summary of the interface problems between the metallic Na anode and NASICON arising from mechanical,chemical,and electrochemical aspects(i.e.,poor interface contact,insulating side-reaction products,and irregular dendrite growth).Subsequently,we systematically analyze and logically categorize modification strategies for addressing anode interface problems and provide a comprehensive discussion on the underlying enhancement *** such,we identify underlying and universal interface enhancement mechanisms by comparatively studying various modification ***,we briefly summarize the challenges in the cathode/electrolyte interface and early-stage research efforts in constructing stable cathode/electrolyte interface and fabricating high-performance composite ***,key suggestions and future prospectives for the advancement of NASICON-based ASSSMBs are outlined.

关键词： All-solid-state sodium-metal batteries NASICON solid electrolytes Interface modification Sodium dendrites Electrochemical performances

Effects of magnesium and copper additions on tensile properties of Al-Si-Cr die casting alloy under as-cast and T5 conditions

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China Foundry 2023年第1期20卷 12-22页

作者： Hong-yi zhan.Yi-wu Xu Pan Wang Jian-feng Wang Jin-ping Li le-peng zhan. General Motors Global Research&Development China Science LaboratoryShanghai 201206China School of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China General Motors(China)Investment Co. Ltd.Shanghai 201206China China International Intellectech Corporation(CIIC) Beijing 100004China

Aluminum high pressure die casting(HPDC)technology has evolved in the past decades,enabling stronger and larger one-piece casting with significant part *** also offers a higher design freedom for more mass-efficient thin-walled body *** body structures that require excellent ductility and fracture toughness to be joined with steel sheet via self-piercing riveting(for instance,shock towers and hinge pillars,etc.),a costly T7 heat treatment comprising a solution heat treatment at elevated temperatures(450℃-500℃)followed by an over-ageing heat treatment is needed to optimize microstructure for meeting product *** enable cost-efficient mass production of HPDC body structures,it is important to eliminate the expensive T7 heat treatment without sacrificing mechanical *** die cast alloy chemistry is a potential solution to improve fracture toughness and ductility of the HPDC *** present study intends to tailor the Mg and Cu additions for a new Al-Si-Cr type die casting alloy(registered as A379 with The Aluminum Association,USA)to achieve the desired tensile properties without using T7 heat *** was found that Cu addition should be avoided,as it is not effective in enhancing strength while degrades tensile *** addition is very effective in improving strength and has minor impact on tensile *** investigated Al-Si-Cr alloy with a nominal composition of Al-8.5wt.%Si-0.3wt.%Cr-0.2wt.%Fe shows comparable tensile properties with the T7 treated AlSi10MnMg alloy which is currently used for manufacturing shock towers and hinge pillars.

关键词： Al-Si alloy intermetallics high pressure die casting tensile property T7 heat treatment

Support Vector Machine combined with K-Nearest Neighbors for Solar Flare Forecasting

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Chinese Journal of Astronomy and Astrophysics 2007年第3期7卷 441-447页

作者： Rong Li Hua-Ning Wang Han He Yan-Mei Cui zhan.le Du National Astronomical Observatories Chinese Academy of Sciences Beijing 100012

A method combining the support vector machine （SVM） the K-Nearest Neighbors （KNN）, labelled the SVM-KNN method, is used to construct a solar flare forecasting model. Based on a proven relationship between SVM and KNN, the SVM-KNN method improves the SVM algorithm of classification by taking advantage of the KNN algorithm according to the distribution of test samples in a feature space. In our flare forecast study, sunspots and 10cm radio flux data observed during Solar Cycle 23 are taken as predictors, and whether an M class flare will occur for each active region within two days will be predicted. The SVM- KNN method is compared with the SVM and Neural networks-based method. The test results indicate that the rate of correct predictions from the SVM-KNN method is higher than that from the other two methods. This method shows promise as a practicable future forecasting model.

关键词： Sun flare - Sun sunspot - Sun activity - Sun magnetic fields