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The effect of the guide field on energy conversion during collisionless magnetic reconnection

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Earth and Planetary Physics 2023年第4期7卷 436-444页

作者： Hui Xiao ZhiHong Zhong Meng Zhou YongYuan Yi LiangJin Song ye pang XiaoHua Deng School of Physics and Materials Science Nanchang UniversityNanchang 330031China Institute of Space Science and Technology Nanchang UniversityNanchang 330031China School of Resources and Environment Nanchang UniversityNanchang 330031China

Magnetic reconnection is well known as an efficient mechanism for transferring magnetic energy into plasma energy.However,how the energy conversion and partition between different species is influenced by the shear angle of the reconnecting magnetic component(i.e.,the guide field strength)is not well understood.Using 2.5-dimensional particle-in-cell simulations,we investigated the energy conversion in reconnection with different guide fields.We found that the overall energy conversion first decreases steeply and then increases slowly when the guide field increases fromB_(g)=0 toB_(g)=4.The increase in energy conversion in the large guide field regime is due to the electron energy gain through the perpendicular channelJ_(⊥)·E_(⊥).The overall energy conversion is predominantly contributed byJ_(⊥)·E_(⊥) rather thanJ||E||.We further find that energy conversion mainly occurs within the reconnection front and the flux pileup region.However,the contribution from the fore reconnection front becomes important in large guide field regimes(3

关键词： collisionless magnetic reconnection energy conversion guide field particle-in-cell simulation

The effect of cavity density on the formation of electrostatic shock in the lunar wake: 1-D hybrid simulation

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Earth and Planetary Physics 2020年第3期4卷 223-230页

作者： Yuan Jin ye pang Institute of Space Science and Technology Nanchang UniversityNanchang 330031China School of Information Engineering Nanchang UniversityNanchang 330031China

One-dimensional hybrid simulations are carried out to study the plasma refilling process in the lunar wake.Previous theoretical and simulation studies have shown that ion-ion acoustic(ⅡA)instability can be initiated and electrostatic shock can be formed under the condition Te>>Ti.We find that the time evolution ofⅡA instability and the formation of electrostatic shock strongly depend on initial cavity density.The initial position of the electrostatic shock is dependent on the ratio between initial cavity density and background solar wind density,i.e.,the farther away the initial position,the lower is the ratio.When the initial cavity density is low enough,the density and electric field profile across the wake become much complex.Meanwhile,the back-to-back electrostatic shock is unstable in the case of lower cavity densities;at the late evolution stage,a new shock-like structure can be formed at the central region of the lunar wake.

关键词： plasma refilling ion-ion acoustic instability Moon wake electrostatic shock

数字货币在国际贸易中的运用及其对传统金融体系的挑战

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价格月刊 2024年第7期 87-94页

作者：庞野县祥悉尼大学澳大利亚新南威尔士洲2006 西南医科大学四川泸州646000

数字货币在国际贸易中表现出巨大的潜力。数字货币通过其高效和低成本的特点,为国际贸易提供了更为便捷的支付方式。其跨境支付的便利性和实时性,使交易双方可以绕过传统的银行体系,降低交易成本,加速资金流转。然而,这种新兴支付方式... 详细信息

数字货币在国际贸易中表现出巨大的潜力。数字货币通过其高效和低成本的特点,为国际贸易提供了更为便捷的支付方式。其跨境支付的便利性和实时性,使交易双方可以绕过传统的银行体系,降低交易成本,加速资金流转。然而,这种新兴支付方式也对传统金融体系造成了冲击。传统金融机构面临着业务流失、监管难度增加和市场竞争加剧等多重挑战。此外,数字货币的匿名性和去中心化特性也增加了监管的难度,对现有的金融法规与国际合作机制提出了新的要求。通过探讨数字货币在国际贸易中的运用及其对传统金融体系带来的挑战。为应对这些挑战,金融机构、政府与监管机构需要密切合作,探索数字货币与传统金融体系的融合之道,以确保金融市场的稳定和发展。

关键词：数字货币国际贸易运用传统金融体系跨境支付

Observation of directional change of core field inside flux ropes within one reconnection diffusion region in the Earth's magnetotail

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Chinese Science Bulletin 2014年第34期59卷 4797-4803页

作者： Shiyong Huang ye pang Zhigang Yuan Xiaohua Deng Jiansen He Meng Zhou Huishan Fu Song Fu Huimin Li Dedong Wang Haimeng Li School of Electronic and Information Wuhan University Institute of Space Science and Technology Nanchang University School of Earth and Space Sciences Peking University Space Science Institute School of Astronautics Beihang University

Two consecutive magnetic flux ropes, separated by less than 30 s(Dt \ 30 s), are observed within one magnetic reconnection diffusion region without strong guide field in the Earth's magnetotail by Cluster multispacecraft. The flux ropes are characterized by bipolar signatures of the south–north magnetic field component Bz accompanied with strong core magnetic field By, intense current J and density depletions inside of them. In spite of the small but non-trivial global scale negative guide field(–By), there exists a directional change of the core fields of two flux ropes, i.e.,-Byfor the first one, and Byfor the second one. The directions of the core fields are the same as the ambient cross-tail magnetic field component(By) just outside of flux ropes. Therefore, we suggest that the core field of flux ropes is formed by compression of the local preexisting Byand that the directional change of core field is due to the change of local preexisting By. Such a change in ambient Bymight be caused by some microscale physics.

关键词：磁通量绳索字段扩散地球观测连接磁场分量

施氮对陇中黄土高原旱作麦田N_(2)O和CO_(2)排放的影响

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甘肃农业大学学报 2024年第3期59卷 81-89页

作者：何锦煜袁建钰闫丽娟杜梦寅庞晔成思潮李广甘肃农业大学林学院甘肃兰州730070

【目的】探究陇中黄土高原半干旱区旱作麦田土壤N_(2)O和CO_(2)排放对不同施氮量的响应,阐明旱作麦田N_(2)O和CO_(2)排放特征及其主要影响因素,以期为该地区旱作麦田温室气体减排和氮肥管理提供依据。【方法】以陇中黄土高原旱作麦田为... 详细信息

【目的】探究陇中黄土高原半干旱区旱作麦田土壤N_(2)O和CO_(2)排放对不同施氮量的响应,阐明旱作麦田N_(2)O和CO_(2)排放特征及其主要影响因素,以期为该地区旱作麦田温室气体减排和氮肥管理提供依据。【方法】以陇中黄土高原旱作麦田为研究对象,采用大田定位试验和室内指标测定相结合的方法,布设CK(不施肥)、LN(低量氮肥)、MN(中量氮肥)和HN(高量氮肥)共4个施氮梯度,分析不同施氮量对旱作麦田土壤硝态氮(NO_(3)^(-)-N)、铵态氮(NH_(4)^(+)-N)、有机碳(SOC)、土壤温度、含水量及土壤N_(2)O和CO_(2)排放的影响。【结果】0~10 cm土层土壤中,HN、MN、LN较CK处理,NO_(3)^(-)-N平均含量增幅为21.55%、26.06%和34.11%;NH_(4)^(+)-N平均含量增幅为21.77%、31.42%和39.20%;SOC平均含量增幅为20.43%、25.80%和35.9%。HN、MN、LN较CK处理,N_(2)O累计排放量增幅为78.63%、130.47%、217.51%;CO_(2)累计排放量增幅为5.73%、10.63%、21.75%。皮尔逊相关关系表明,不同施氮处理中,麦田0~10 cm土层土壤中NO_(3)^(-)-N、NH_(4)^(+)-N和SOC平均含量与N_(2)O、CO_(2)累计排放量呈极显著正相关关系(P<0.001),土壤温度与N_(2)O和CO_(2)累计排放量呈显著正相关关系(P<0.05),土壤含水量与N_(2)O累计排放量呈显著的负相关关系(P<0.05),与CO_(2)累计排放量相关关系不显著。【结论】施氮可以增加黄土高原旱作麦田表层土壤中NO_(3)^(-)-N、NH_(4)^(+)-N和SOC含量,进而增加了N_(2)O和CO_(2)累计排放量,是该地区麦田N_(2)O和CO_(2)排放的主要驱动因子,表层土温和土壤含水量也一定程度上影响着N_(2)O和CO_(2)的排放。

关键词：旱作麦田施氮量 N_(2)O CO_(2) 排放通量陇中黄土高原

Larmor Electric Field in Symmetric Magnetic Reconnection

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Larmor Electric Field in Symmetric Magnetic Reconnection

2022年中国地球科学联合学术年会

作者： Yongyuan Yi Meng Zhou Liangjin Song Zhihong Zhong ye pang Xiaohua Deng Nanchang University

Larmor electric field was previously found as a unique feature of asymmetry reconnection. Using 2.5-D particle-in-cell simulations, we show that the Larmor electric field also exists in symmetric reconnection, manifested as a transient structure upstream of the Hall electric field. The Larmor electric field emerges during the rapid growth phase of the reconnection rate and has opposite polarity to the Hall field.

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纯电无人矿卡线控底盘技术开发及应用

汽车电器 2024年第4期 19-20页

作者：田双双张维行邵金萍秦玉军庞烨潍柴动力股份有限公司山东潍坊261061

文章简要介绍线控底盘技术开发后在无人矿卡上的实际应用,通过讲解线控底盘的结构、工作原理及无人纯电矿卡的使用优势和巨大使用潜力,阐述线控底盘在无人纯电矿卡作业中的作用。应用在露天煤矿工作环境的矿车不仅可提升作业效率,还可... 详细信息

文章简要介绍线控底盘技术开发后在无人矿卡上的实际应用,通过讲解线控底盘的结构、工作原理及无人纯电矿卡的使用优势和巨大使用潜力,阐述线控底盘在无人纯电矿卡作业中的作用。应用在露天煤矿工作环境的矿车不仅可提升作业效率,还可避免燃油矿卡造成的污染,实现绿色矿山。

关键词：线控底盘无人驾驶无人矿卡绿色矿山

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980 nm Near-Infrared Light-Emitting Diode Using All-Inorganic Perovskite Nanocrystals Doped with Ytterbium Ions

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Tsinghua Science and Technology 2024年第1期29卷 207-215页

作者： Zhenglan ye Taoran Liu Dan Chen Yazhou Yang Jiayi Li Yaqing pang Xiangquan Liu Yuhua Zuo Jun Zheng Zhi Liu Buwen Cheng State Key Laboratory on Integrated Optoelectronics Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China Intelligent Network Research Institute Zhejiang LabHangzhou 311100China

All-inorganic perovskite(CsPbX3)nanocrystals(NCs)have recently been widely investigated as versatile solution-processable light-emitting materials.Due to its wide-bandgap nature,the all-inorganic perovskite NC Light-Emitting Diode(LED)is limited to the visible region(400-700 nm).A particularly difficult challenge lies in the practical application of perovskite NCs in the infrared-spectrum region.In this work,a 980 nm NIR all-inorganic perovskite NC LED is demonstrated,which is based on an efficient energy transfer from wide-bandgap materials(CsPbCl3 NCs)to ytterbium ions(Yb3+)as an NIR emitter doped in perovskite NCs.The optimized CsPbCl3 NC with 15 mol%Yb3+doping concentration has the strongest 980 nm photoluminescence(PL)peak,with a PL quantum yield of 63%.An inverted perovskite NC LED is fabricated with the structure of ITO/PEDOT:PSS/poly-TPD/CsPbCl3:15 mol%Yb3+NCs/TPBi/LiF/Al.The LED has an External Quantum Efficiency(EQE)of 0.2%,a Full Width at Half Maximum(FWHM)of 47 nm,and a maximum luminescence of 182 cd/m?.The introduction of Yb3+doping in perovskite NCs makes it possible to expand its working wavelength to near-infrared band for next-generation light sources and shows potential applications for optoelectronic integration.

关键词： perovskite nanocrystals rare-earth doping Light-Emitting Diode(LED) near-infrared optical interconnection

基于多距离声阵实测回归传播损失的浅水域水下辐射噪声源级测量方法

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船舶力学 2023年第4期27卷 598-606页

作者：庞业珍俞孟萨中国船舶科学研究中心船舶振动噪声重点实验室江苏无锡214082

浅水域水下辐射噪声传播会受到海面与海底反射的影响。基于传统单水听器方法进行浅水域船舶水下辐射噪声源级测量相比深水域测量面临三个问题:(1)浅水域声场中复杂的声场分布特征会增加单水听器测量结果的不确定度;(2)浅水域传播损失系... 详细信息

浅水域水下辐射噪声传播会受到海面与海底反射的影响。基于传统单水听器方法进行浅水域船舶水下辐射噪声源级测量相比深水域测量面临三个问题:(1)浅水域声场中复杂的声场分布特征会增加单水听器测量结果的不确定度;(2)浅水域传播损失系数小于深水域,采用球面波衰减系数进行源级修正会带来较大偏差;(3)水听器近水面布放会导致测量结果受到水面镜像反射的影响比深水域更大。本文提出一种工程化的基于多距离声阵实测传播损失的浅水域船舶水下辐射噪声源级推算方法,在浅水域测量船舶水下辐射噪声源级时剥离界面反射的影响,得到自由场环境下船舶水下辐射噪声源特性。利用不少于3个正横距离分析该海域的传播损失系数,并提出剥离水面劳埃德镜像效应的修正公式。为了验证该方法的有效性,使用UW350声源模拟船舶噪声源在千岛湖开展验证试验,试验结果表明,在20 Hz~1 kHz频段内,推算得到的声源级频谱与1m处参考水听器测量声压级频谱平均偏差小于3 dB。

关键词：船舶噪声浅水域传播损失水听器声阵