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The dawn−dusk asymmetry in mesosphere and lower thermosphere temperature disturbances during geomagnetic storms at high latitude

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Earth and Planetary Physics 2024年第2期8卷 356-367页

作者： GuanChun Wei jianyong lu Fen Tang JingYuan Li Meng Sun Institute of Space Weather School of Atmospheric PhysicsNanjing University of Information Science&TechnologyNanjing 210044China College of Information and Communication National University of Defense TechnologyWuhan 430019China

Utilizing observations by the Sounding of the Atmosphere using Broadband Emission Radiometry(SABER)instrument,we quantitatively assessed the dawn-dusk asymmetry in temperature disturbances within the high-latitude mesosphere and lower thermosphere(MLT)during the main phase of geomagnetic storms in this study.An analysis of five geomagnetic superstorm events indicated that during the main phase,negative temperature disturbances were more prevalent on the dawn side than on the dusk side in the high-latitude MLT region.Results of a statistical analysis of 54 geomagnetic storm events also revealed a notable disparity in temperature disturbances between the dawn and dusk sides.At high latitudes,38.2%of the observational points on the dawn side exhibited negative temperature disturbances(less than−5 K),whereas on the dusk side,this percentage was only 29.5%.In contrast,at mid-latitudes,these proportions were 34.1%and 36.5%,respectively,showing no significant difference.We also conducted a statistical analysis of temperature disturbances at different altitudes,which revealed an increase in the proportion of warming disturbances with altitude.Conversely,the proportion of cooling disturbances initially rose with altitude,reaching a peak around 105 km,and subsequently decreased.These temperature disturbance differences could be explained by the day-night asymmetry in vertical wind disturbances during storm conditions.

关键词： dawn dusk asymmetry SABER(Sounding of the Atmosphere using Broadband Emission Radiometry) geomagnetic storms mesosphere and lower thermosphere

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Statistical study of “trunk-like” heavy ion structures in the inner magnetosphere

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Earth and Planetary Physics 2022年第4期6卷 339-349页

作者： Hao Zhang YaBing Wang jianyong lu Institute of Space Weather Nanjing University of Information Science&TechnologyNanjing 210044China Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China

We present a statistical study of“trunk-like”structures observed in He+and O+in the inner magnetosphere.The main characteristic of these structures is that the energy of the peak flux decreases earthward.Using observations from the Helium Oxygen Proton Electron(HOPE)instrument onboard Van Allen Probe A,we identify the trunks observed from November 2012 to June 2019 and obtain the universal time,L shell,magnetic local time(MLT),and energy information of each trunk’s root and tip.We then investigate the behavior of trunks in terms of their frequency of occurrence,temporal evolution,spatial and energy distribution,and trunk dependence on different geomagnetic indices.We find that(1)the trunks are always located at L=1.5−4.0 and have a preferential location mainly concentrated at MLT=18−24,(2)the sector within MLT=14−16 is a forbidden zone without trunk roots,and(3)the energy of He+ trunks is the largest near dusk and gradually decreases in the counterclockwise direction,whereas the energy of O+ trunks is relatively evenly distributed with MLT and L.The differences between He+ and O+ trunks are probably due to the different charge exchange and Coulomb collision lifetime.The dependence on different geomagnetic indices indicates that the trunk structures occur more frequently during relatively quiet periods.

关键词： "trunk-like"heavy ion structures spatial and energy distribution geomagnetic activity dependence

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Formation of the bow shock indentation: MHD simulation results

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Earth and Planetary Physics 2021年第3期5卷 259-269页

作者： BaoHang Qu jianyong lu Ming Wang HuanZhi Yuan Yue Zhou HanXiao Zhang Institute of Space Weather School of Math&StatisticsNanjing University of Information Science&TechnologyNanjing 210044China Key Laboratory of Earth and Planetary Physics Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China

Simulation results from a global magnetohydrodynamic(MHD)model are used to examine whether the bow shock has an indentation and characterize its formation conditions,as well as its physical mechanism.The bow shock is identified by an increase in plasma density of the solar wind,and the indentation of the bow shock is determined by the shock flaring angle.It is shown that when the interplanetary magnetic field(IMF)is southward and the Alfvén Mach number(Mα)of solar wind is high(>5),the bow shock indentation can be clearly determined.The reason is that the outflow region of magnetic reconnection(MR)that occurs in the low latitude area under southward IMF blocks the original flow in the magnetosheath around the magnetopause,forming a high-speed zone and a low-speed zone that are upstream and downstream of each other.This structure hinders the surrounding flow in the magnetosheath,and the bow shock behind the structure widens and forms an indentation.When Mαis low,the magnetosheath is thicker and the disturbing effect of the MR outflow region is less obvious.Under northward IMF,MR occurs at high latitudes,and the outflow region formed by reconnection does not block the flow inside the magnetosheath,thus the indentation is harder to form.The study of the conditions and formation process of the bow shock indentation will help to improve the accuracy of bow shock models.

关键词： indentation of bow shock global MHD simulation interplanetary magnetic field Bz Alfvén Mach number

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Magnetosphere response to the IMF turning from north to south

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Earth and Planetary Physics 2019年第1期3卷 8-16页

作者： jianyong lu HanXiao Zhang Ming Wang ChunLi Gu HaiYan Guan Institute of Space Weather School of Math & Statistics Nanjing University of Information Science & Technology Beijing Institute of Applied Meteorology School of Remote Sensing & Geomatics Engineering Nanjing University of Information Science & Technology

In this paper, the Space Weather Modeling Framework(SWMF) is used to simulate the real-time response of the magnetosphere to a solar wind event on June 5, 1998, in which the interplanetary magnetic field shifted its direction from north to south.Since most current models do not take into account convective effects of the inner magnetosphere, we first study the importance of Rice Convection Model(RCM) in the global model.We then focus on the following four aspects of the magnetosphere's response: the magnetosphere's density distribution, the structure of its magnetic field lines, the area of the polar cap boundary, and the corresponding ionospheric current change.We find that(1) when the IMF changes from north to south in this event, high magnetosheath density is observed to flow downstream along the magnetopause with the solar wind; low-latitude reconnection at dayside occurs under the southward IMF, while the magnetic field lines in the tail lobe caudal, caused by the nightside high latitude reconnection, extend into the interplanetary space.Open magnetic field lines exist simultaneously at both high and low latitudes at the magnetopause;(2) the area of the polar cap is obviously increased if the IMF turns from the north to the south; this observation is highly consistent with empirical observations;(3) the ionospheric field align current in the northern hemisphere is stronger than in the southern hemisphere and also increases as the IMF changes from north to south.SWMF with the Rice Convection effect provides reliable modeling of the magnetospheric and ionospheric response to this solar wind variation.

关键词： magnetosphere global MHD simulation polar cap magnetic reconnection

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Experimental investigation about the effect of non-axisymmetric wake impact on a low speed axial compressor

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Acta Mechanica Sinica 2010年第2期26卷 305-312页

作者： jianyong Liu Yajun lu Zhiping Li National Key Laboratory on Aero-engine Beihang University 100191 Beijing China

Non-axisymmetric wake impact experiments were carried out after the best exciting frequency for a low speed axial compressor had been found by axisymmetric wake impact experiments. When the number and circumferential distribution of inlet guide vanes （IGV） are logical, the wakes of non-axisymmetric IGVs can exert beneficial unsteady exciting effect on their downstream rotor flow fields and improve the compressor＇s performance. In the present paper, four non-axisymmetric wake impact plans were found working better than the axisymmetric wake impact plan. Compared with the base plan, the best non-axisymmetric plan increased the compressor＇s peak efficiency, and the total pressure rise by 1.1 and 2%, and enhanced the stall margin by 4.4%. The main reason why non-axisymmetric plans worked better than the axisymmetric plan was explained as the change of the unsteady exciting signal arising from IGV wakes. Besides the high-frequency components, the nonaxisymmetric plan generated a beneficial low-frequency square-wave exciting signal and other secondary frequency components. Compared with the axisymmetric plan, multifrequency exciting wakes arising from the non-axisymmetric plans are easier to get coupling relation with complex vortices such as clearance vortices, passage vortices and shedding vortices.

关键词： Axial compressor· Non-axisymmetric · Wake ·Coupling

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Nonlinear dispersive scale Alfvén waves in magnetosphere-ionosphere coupling:Physical processes and simulation results

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Chinese Science Bulletin 2012年第12期57卷 1384-1392页

作者： ZHAO MingXian lu jianyong Chinese Academy of Meteorological Sciences Beijing 100081China Graduate University of Chinese Academy of Sciences Beijing 100049China National Center for Space Weather China Meteorology AdministrationBeijing 100081China

Dispersive Alfvén waves(DAWs)have been demonstrated to play a significant role in auroral generation of the magnetosphereionosphere coupling system.Starting from a two fluid reduced MHD model,we summarize the frequency,temporal and spatial characteristics of magnetospheric DAWs.Then,the nonlinear kinetic and inertial scale Alfveén waves are studied,and we review some theoretical aspects and simulation results of dispersive Alfve′n waves in Earth's magnetosphere.It is shown that dispersive standing Alfve′n waves can generate the field-aligned currents which transport energy into the auroral ionosphere,where it is dissipated by Joule heating and energy lost due to electron precipitation.The Joule dissipation can heat the ionospheric electron and produce changes in the ionospheric Pedersen conductivity.As a feedback,the conducting ionosphere can also strongly affect the magnetospheric currents. The ponderomotive force can cause the plasma to move along the field line,and generate ionospheric density cavity.The nonlinear structuring can lead to a dispersive scale to accelerate auroral particle,and the Alfvn waves can be trapped within the density cavity. Finally,we show the nonlinear decay of dispersive Alfvén waves related to two anti-propagating electron fluxes observed in the auroral zone.

关键词： Alfven波电离层耦合非线性色散磁层仿真结果物理过程阿尔文波耦合系统

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Dipole tilt controls bow shock location and flaring angle

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Science China Earth Sciences 2017年第1期60卷 198-206页

作者： lu jianyong YUAN HuanZhi WANG Ming YANG YaFen Institute of Space Weather College of Math & StatisticsNanjing University of Information Science & Technology National Center for Space Weather China Meteorological Administration

The dipole tilt angle has beenfound to affect Earth's bow shock.This work presents a quantitative relationship between the dipole tilt angle and the bow shock location and flaring angle.We collected a large data set of bow shock crossings from four different satellites(IMP 8,Geotail,Magion 4,and Cluster),including some recent crossings obtained during 2012-2013.The results from a statistical analysis demonstrate that:(1)the subsolar standoff distance increases but the flaring angle decreases with increasing dipole tilt angle;(2)when the dipole tilt angle changes sign from negative to positive,the dayside bow shock moves toward Earth and the shift can be as much as 2.29 R_E,during which the flaring angle increases;and(3)the shape of bow shock in the northern and southern hemispheres differs.For the northern hemisphere bow shock,with increasing positive/negative dipole tilt angle,the flaring angle increases/decreases.While for the southern hemisphere,the trend is the opposite;with increasing positive/negative dipole tilt angle,the flaring angle decreases/increases.These results are helpful for future bow shock modeling that needs to include the effects of dipole tilt angle.

关键词：弯吃惊偶极子倾斜联合的太阳的风磁气圈

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FGF21-mediated autophagy:Remodeling the homeostasis in response to stress in liver diseases

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Genes & Diseases 2024年第3期11卷 264-274页

作者： Wei Shen Modan Yang Hao Chen Chiy He Huigang Li Xinyu Yang jianyong Zhuo Zuyuan Lin Zhihang Hu Di lu Xiao Xu Zhejiang University School of Medicine HangzhouZhejiang 310058China Key Laboratory of Integrated Oncology and Intelligent Medicine of Zhejiang Province Department of Hepatobiliary and Pancreatic SurgeryAffiliated Hangzhou First People's HospitalZhejiang University School of MedicineHangzhouZhejiang 310006China The Institute for Organ Repair and Regenerative Medicine of Hangzhou HangzhouZhejiang 310006China Institute of Organ Transplantation Zhejiang UniversityHangzhouZhejiang 310003China National Center for Healthcare Quality Management in Liver Transplant HangzhouZhejiang 310003China

Liver diseases are worldwide problems closely associated with various stresses,such as endoplasmic reticulum stress.The exact interplay between stress and liver diseases remains unclear.Autophagy plays an essential role in maintaining homeostasis,and recent studies indicate tight crosstalk between stress and autophagy in liver diseases.Once the bal-ance between damage and autophagy is broken,autophagy can no longer resist injury or main-tain homeostasis.In recent years,FGF21(fibroblast growth factor 21)-induced autophagy has attracted much attention.FGF21 is regarded as a stress hormone and can be up-regulated by an abundance of signaling pathways in response to stress.Also,increased FGF21 activates autophagy by a complicated signaling network in which mTOR plays a pivotal role.This review summarizes the mechanism of FGF21-mediated autophagy and its derived application in the defense of stress in liver diseases and offers a glimpse into its promising prospect in future clinical practice.

关键词： Autophagy Fibroblast growth factor 21 Liver diseases mTOR Stress

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2020—2023年深圳市宝安区游泳池水质卫生状况分析

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职业卫生与病伤 2024年第1期39卷 55-60页

作者：洪烈城林锐锋李秀华刘庆成罗妃珍陆剑勇深圳市宝安区公共卫生服务中心广东深圳518102 宝安现场流行病学培训项目一期广东深圳518101 深圳市宝安区疾病预防控制中心广东深圳518101

目的了解深圳市宝安区游泳场所水质现状,为卫生监督管理提供科学依据。方法选择深圳市宝安区2020—2023年持证且对外营业的游泳场所进行抽检,共采集游泳池水样615份,对其游离性余氯、尿素、pH值、大肠菌群、浑浊度等水质指标开展检测... 详细信息

目的了解深圳市宝安区游泳场所水质现状,为卫生监督管理提供科学依据。方法选择深圳市宝安区2020—2023年持证且对外营业的游泳场所进行抽检,共采集游泳池水样615份,对其游离性余氯、尿素、pH值、大肠菌群、浑浊度等水质指标开展检测和评价,用水质合格率对各指标进行描述分析,分类变量组间率的比较用χ2检验,检验水准为α=0.05。当多组率总体比较有差异时,使用Bonferroni法进行两两比较,α’=0.05/3=0.017。使用SPSS 27.0进行统计分析。结果 2020—2023年深圳市宝安区游泳场所监测水质总体合格率分别为93.41%、96.06%、96.86%、98.08%,4年水质总体合格率差异无统计学意义(χ^(2)=3.671,P=0.288),监测指标中细菌总数4年平均合格率最低(98.37%),其次为尿素(98.86%)。住宅小区泳池、公共泳池、酒店泳池水质合格率分别为95.34%(450/472)、100.00%(97/97)和100.00%(46/46),差异有统计学意义(χ^(2)=11.889,P=0.032)。安装水质在线监测设备的游泳场所水质合格率高于未安装者(χ^(2)=7.769,P=0.005)。人工投药游泳场所、自动投药与人工投药相结合游泳场所、自动投药游泳场所水质合格率分别为94.49%(326/345)、98.08%(191/194)和100.00%(76/76),差异有统计学意义(χ^(2)=8.865,P=0.012)。结论深圳市宝安区游泳场所水质卫生现状仍待改善,卫生监督部门应将住宅小区游泳池作为重点监管类型,同时积极推进游泳场所水质在线监测设备的安装。

关键词：游泳池水质卫生状况

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Dependence of magnetic field just inside the magnetopause on subsolar standoff distance:Global MHD results

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Chinese Science Bulletin 2012年第12期57卷 1438-1442页

作者： WANG Ming lu jianyong LIU ZiQian PEI ShiXin College of Math ＆ Physics Nanjing University of Information Science ＆ Technology Nanjing 210044 China National Center for Space Weather China Meteorology Administration Beijing 100081 China Chinese Academy of Meteorological Sciences Beijing 100081 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

The subsolar magnetopause is the boundary between the solar wind and the Earth's magnetosphere,where reduced solar wind dynamic pressure is equal to the magnetic pressure of the Earth's outer magnetosphere.We use a global magnetohydrodynamic (MHD)model to estimate the ratio f of the compressed magnetic field just inside the subsolar magnetopause to the purely dipolar magnetic field.We also compare our numerical results to a similar work by Shue,which used Time History of Events and Macroscale Interactions during Substorms(THEMIS)data.Our results show that the ratio f is linearly proportional to the subsolar magnetopause standoff distance(r0)for both the northward and southward interplanetary magnetic field,properties consistent with Shue but with a smaller proportionality constant.However,previous theoretical studies show that f is nearly independent of the subsolar standoff distance.The global model results also show that f is smaller for the southward Interplanetary Magnetic Field(IMF)under the same r0,and that the proportionality constant for the southward IMF is larger than that for the northward IMF.Both conclusions agree with statistical results from observations by Shue.

关键词：行星际磁场地球磁层磁流体距离国际货币基金组织模型估计相互作用历史事件

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