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An embedded electron current layer observed at the edge of the plasma sheet in the Earth’s magnetotail

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Earth and Planetary Physics 2025年第1期9卷 148-158页

作者： ChenChen zhan RongSheng Wang QuanMing Lu San Lu XinMin Li Deep Space Exploration Laboratory/School of Earth and Space Sciences University of Science and Technology of ChinaHefei 230026China Chinese Academy of Sciences(CAS)Center for Excellence in Comparative Planetology/CAS Key Laboratory of Geospace Environment/Anhui Mengcheng National Geophysical Observatory University of Science and Technology of ChinaHefei 230026China Collaborative Innovation Center of Astronautical Science and Technology Harbin 150001China

The formation of an embedded electron current sheet within the magnetotail plasma sheet has been poorly *** this article,we present an electron current layer detected at the edge of the magnetotail plasma *** ions were demagnetized inside the electron current layer,but the electrons were still frozen in with the magnetic field ***,this decoupling of ions and electrons gave rise to a strong Hall electric field,which could be the reason for the formation of the embedded thin current *** magnetized electrons,the absence of the nongyrotropic electron distribution,and negligible energy dissipation in the layer indicate that magnetic reconnection had not been triggered within the embedded thin current *** highly asymmetric plasma on the two sides of the current layer and low magnetic shear across it could suppress magnetic *** observations indicate that the embedded electric current layer,probably generated by the Hall electric field,even down to electron scale,is not a sufficient condition for magnetic reconnection.

关键词： magnetotail plasma sheet magnetic reconnection

Remarks on the Three-dimensional Lattice Model

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Chinese Physics Letters 1996年第6期13卷 412-415页

作者： HU zhan-ning Institute of Theoretical Physics Chinese Academy of SciencesBeijing 100080

We find the connection between the weight functions of the three-dimensional(3D)Bazhanov-Baxter model and the 3D vertex model proposed by Mangazeev et *** the weight function of the 3D integrable model with the modifi... 详细信息

关键词： form. vertex integrable

The relationships of solar flares with both sunspot and geomagnetic activity

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Research in Astronomy and Astrophysics 2012年第4期12卷 400-410页

作者： zhan-Le Du Hua-ning Wang Key Laboratory of Solar Activity National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100012China

The relationships between solar flare parameters （total importance, time duration, flare index, and flux） and sunspot activity （R z ） as well as those between geomagnetic activity （aa index） and the flare parameters can be well described by an integral response model with the response time scales of about 8 and 13 months, respectively. Compared with linear relationships, the correlation coefficients of the flare parameters with R z , of aa with the flare parameters, and of aa with R z based on this model have increased about 6%, 17%, and 47% on average, respectively. The time delays between the flare parameters with respect to R z , aa to the flare parameters, and aa to R z at their peaks in a solar cycle can be predicted in part by this model （82%, 47%, and 78%, respectively）. These results may be further improved when using a cosine filter with a wider window. It implies that solar flares are related to the accumulation of solar magnetic energy in the past through a time decay factor. The above results may help us to understand the mechanism of solar flares and to improve the prediction of the solar flares.

关键词： Sun: activity -- Sun: sunspots -- Sun: flares -- geomagnetic activity

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

Runoff of arid and semi-arid regions simulated and projected by CLM-DTVGM and its multi-scale fluctuations as revealed by EEMD analysis

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Journal of Arid Land 2016年第4期8卷 506-520页

作者： ning Like XIA Jun zhan Chesheng zhanG Yongyong Key Laboratory of Water Cycle&Related Land Surface Processes Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China State Key Laboratory of Water Resources&Hydropower Engineering Science Wuhan UniversityWuhan 430000China

Runoff is a major component of the water cycle, and its multi-scale fluctuations are important to water resources management across arid and semi-arid regions. This paper coupled the Distributed Time Variant Gain Model （DTVGM） into the Community Land Model （CLM 3.5）, replacing the TOPMODEL-based method to simulate runoff in the arid and semi-arid regions of China. The coupled model was calibrated at five gauging stations for the period 1980-2005 and validated for the period 2006-2010. Then, future runoff （2010-2100） was simulated for different Representative Concentration Pathways （RCP） emission scenarios. After that, the spatial distributions of the future runoff for these scenarios were discussed, and the multi-scale fluctuation characteristics of the future annual runoff for the RCP scenarios were explored using the Ensemble Empirical Mode Decomposition （EEMD） analysis method. Finally, the decadal variabilities of the future annual runoff for the entire study area and the five catchments in it were investigated. The results showed that the future annual runoff had slowly decreasing trends for scenarios RCP 2.6 and RCP 8.5 during the period 2010-2100, whereas it had a non-monotonic trend for the RCP 4.5 scenario, with a slow increase after the 2050s. Additionally, the future annual runoff clearly varied over a decadal time scale, indicating that it had clear divisions between dry and wet periods. The longest dry period was approximately 15 years （2040-2055） for the RCP 2.6 scenario and 25 years （2045-2070） for the RCP 4.5 scenario. However, the RCP 8.5 scenario was predicted to have a long dry period starting from 2045. Under these scenarios, the water resources situation of the study area will be extremely severe. Therefore, adaptive water management measures addressing climate change should be adopted to proactively confront the risks of water resources.

关键词： Community Land Model (CLM) Distributed Time Variant Gain Model (DTVGM) Ensemble EmpiricalMode Decomposition (EEMD) decadal variability arid and semi-arid regions

Structural properties and catalytic performance of the La-Cu-Zn mixed oxides for CO2 hydrogenation to methanol

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Journal of Rare Earths 2018年第3期36卷 273-280页

作者： Haijuan zhan Zhiqiang Wu ning Zhao Wanyi Liu Wei Wei School of Chemistry and Chemical Engineering Ningxia UniversityYinchuan 750021China State Key Laboratory of High-efficiency Coal Utilization and Green Chemistry Engineering Ningnia UniversityYinchuan 750021China State Key Laboratory of Coal Conversion Institute of Coal ChemistryChinese Academy of SdencesTaiyuan 030001China Center for Greenhouse Gas and Environmental Engineering Shanghai Advanced Research Institute Chinese Academy of SciencesShanghai 201203China

A series of La-Cu-Zn-O mixed oxide catalysts were synthesized by a co-precipitation method and calcined under different temperatures. The XRD, BET, TPR, N2 O-adsorption, XPS, SEM and TPD techniques were carried out to measure the aimed catalysts. The results indicated that the chemical environment of lanthanum element changes with the increase of calcination temperature. The La2 CuO4 perovskite structure is obtained at the temperature higher than 823 K and the special copper species appear in the perovskites due to the special structure property. The catalysts with La2 CuO4 perovskite structure show higher methanol selectivity compared with the mixed copper catalyst. For the perovskite catalysts, the conversion of CO2 changes with the same tendency of the copper species ratio（（Cu^（α＋）＋Cu^0）/（Cu（Total））%）, which implied both Cu^（α＋） and Cu^0 are important active sites in the perovskite catalyst for the reaction.

关键词： La2CuO4 perovskite CO2 hydrogenation Rare earths

中山大学科技期刊出版史略(1866—2024)

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中山大学学报（自然科学版）（中英文） 2025年第1期64卷 1-27页

作者：张冰詹拔群中山大学学报编辑部广东广州510275 中山大学期刊管理中心广东广州510275

本文力图较为完整地展现中山大学100多年的科技期刊出版历史全貌,在明晰中山大学办学源流的基础上将其前身各校的科技期刊出版情况纳入梳理,整理统计出中山大学及其前身各校在正式建校前(1866—1923年)出版科技期刊25种、建校后的民国时... 详细信息

本文力图较为完整地展现中山大学100多年的科技期刊出版历史全貌,在明晰中山大学办学源流的基础上将其前身各校的科技期刊出版情况纳入梳理,整理统计出中山大学及其前身各校在正式建校前(1866—1923年)出版科技期刊25种、建校后的民国时期(1924—1948年)出版科技期刊87种,共和国时期(1949—2024年)出版科技期刊60种,共计172种,并对代表性刊物进行简要介绍。中山大学的科技期刊出版以医学类期刊的贡献最为突出,其影响一直延续至今。这些科技期刊从科研学术角度记录了中山大学的学科发展历史,同时为中国近代科学技术的传播和发展作出了重要的贡献。

关键词：中山大学科技期刊出版史校史

Role of the inter-pass cooling rate in recrystallization behaviors of Ni-based superalloy during interrupted hot compression

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Chinese Journal of Aeronautics 2019年第5期32卷 1314-1330页

作者： Xin zhanG Hongwei LI Mei zhan Siliang YAN ning zhanG State Key Laboratory of Solidification Processing School of Materials Science and Engineering Northwestern Polytechnical University School of Material Science and Engineering Hefei University of Technology

The microstructural evolution of a Ni-based superalloy under interrupted hot compressive deformation with different cooling rates in the inter-pass stage is investigated. It is found that metadynamic recrystallization(MDRX) in the inter-pass stage is more sensitive to the accumulated strain than the deformation temperature which is above the recrystallization temperature. The variations of both the grain distribution and the texture intensity caused by MDRX during the interpass stage result in variations of the yield stress(YS) and the work hardening(WH) rate in each stage. Results also show that the MDRX process in the inter-pass stage has a considerable influence on the final microstructure of three-pass compression. The final grain distribution is more uniform,and the compression texture gradually transforms into recrystallization texture with an increasing degree of MDRX. In order to predict the MDRX fraction in the inter-pass cooling stage, a modified kinetic equation is established, which can reasonably predict the MDRX behavior under multi-pass compression with different conditions in the inter-pass stage. Meanwhile, the influence of the interpass cooling stage on the mechanism of dynamic recrystallization(DRX) is studied. It is universally acknowledged that the discontinuous dynamic recrystallization(DDRX) process is the major deformation mechanism for the Ni-based superalloy. However, the continuous dynamic recrystallization(CDRX) process is promoted in the compression stage with a decrease of the cooling rate in each inter-pass stage.

关键词： Cooling rate Hot compression test Kinetic equation Ni-based superalloy Recrystallization