Energetic electrons associated with magnetic reconnection in the sheath of interplanetary coronal mass ejection

Magnetic reconnection is an important universal plasma dissipation process that converts magnetic energy into plasma thermal and kinetic energy,and simultaneously changes the magnetic field topology.In this paper,we report the first observation of energetic electrons associated with asymmetric reconnection in the sheath of an interplanetary coronal mass ejection.The magnetic field shear angle was about 151°,implying guide-field reconnection.The width of the exhaust was about 8×104 km.The reconnection rate was estimated as 0.044-0.08,which is consistent with fast reconnection theory and previous observations.We observed flux enhancements of energetic electrons with energy up to 400 keV in this reconnection exhaust.The region where ener- getic electron fluxes were enhanced is located at one pair of separatrices in the higher density hemisphere.We discuss these observation results,and compare with previous observations and recent kinetic simulations.     

二维定常的微流边界层解的存在性

证明了二维边界层uδu/δx＋vδu/δy=vδ2u/δy2-dp/dx和δu/δx＋δv/δy=0满足边界条件：内解的存在唯一性,其中：X是适当小的正数;     

WIND observations of plasma waves inside the magnetic cloud boundary layers

Based on the WIND observational data for the plasma waves from thermal noise receptor （TNR） working on the frequency 4-256 kHz and the solar wind and the magnetic fields, we analyze the plasma wave activities in the 60 magnetic cloud＇s boundary layers （BLs） and find that there are often various plasma wave activities in the BLs, which are different from those in the adjacent solar wind （SW） and the magnetic clouds （MC）. The basic characteristics are that： （1） the enhancement of the Langmuir wave near the electronic plasma frequency （fpe） is a dominant wave activity, which occupies 75% investigated samples; （2） the events enhanced both in the langmuir and ion acustic （f〈fpe） waves are about 60% of investigated samples; （3） broadband, continuous enhancement events in the plasma wave activities were observed in the whole frequency band of TNR, and about 30% of the 60 samples, however, were not observed in the SW and the MC investigated events; （4） although the ratio of the temperatures between the electon and proton, Te/Tp ≤1, the ion caustic wave enhancement activities are still often observed in the BLs, which makes it difficult to explain them by the traditional plasma theory. New results reported in this paper further show that the magnetic cloud＇s BL is an important dynamic structure, which could provide useful diagnosis for understanding the cloud＇s BL physics and could expand a space developing space plasma wave theory.     

Double Star TC-1 observation of the earthward flowing plasmoids in the near magnetotail

We analyze Double Star TC-1 magnetic field data from July to September in 2004 and find that plas-moids exist in the very near-Earth magnetotail. It is the first time that TC-1 observes the plasmoids inthe magnetotail at X > ?13 RE. According to the difference of the magnetic field structure in plasmoids,we choose two typical cases for our study: the magnetic flux rope on August 6 with the open magneticfield and the magnetic loop on September 14 with the closed magnetic field. Both of the cases are as-sociated with the high speed earthward flow and the magnetic loop is related to a strong substorm. Theions can escape from the magnetic flux rope along its open field line, but the case of the closed mag-netic loop can trap the ions. The earthward flowing plasmoids observed by TC-1 indicate that the mul-tiple X-line magnetic reconnection occurs beyond the distance of X=?10 RE from the earth.     

蒸汽小流量下减温减压器的实验研究

介绍了减温减压器的工作原理,以及在蒸汽小流量工况下进行的减温过程和减压过程的实验研究。实验结果表明,在蒸汽小流量下减温减压器对蒸汽的减温减压作用明显,工作性能稳定,能够获得需要的出口蒸汽参数,可以为今后的蒸汽排放系统的设计和优化工作提供参考资料。     

自然对流温度边界层的数值解

1 基本方程及解法运动方程和能量方程为式中,β为体膨胀系数;K为导热系数;T_e是边界层外的温度.边界条件为y=0,u=v=0,T=T_w;y=∞,u=0,T=T_e.对上述方程作相似变换后得非线性常微分方程组     

边界层分离流动的三层结构理论计算

在流动分离的高雷诺数渐近理论“三层”理论的基础上,发展了一套计算二维定常不可压脱体分离三层结构的数值方法。采用相互作用程序控制方程组获得了椭圆型的数学结构,克服了传统边界层计算不能通过分离点的困难,得到了分离点附近的流场分布。计算结果令人满意。     

某类奇摄动边值问题解的多重边界层现象

本文揭示了某类四阶半线性常微分方程边值问题解的多重边界层现象,根据不同的层次用不同的伸长变量,分别构造了具有不同量级的边界层校正项,并给出证明摄动问题解存在的充分条件,从而证得关于解的一致有效的渐近展开式和有关的余项估计。     

高速复制机记录磁头磁路分析和计算

分析了高速复制机记录磁头磁路结构的特点，根据磁头漏磁通分布，提出了磁头磁阻计算的等效磁路。为了对磁头磁阻精确求解，对加工过程磁头芯材料中产生的磁性变质层用计算机进行了拟合；磁头磁阻的计算中，分别就磁芯材料的磁导率为实数和数的情况进行了讨论。     

一类非线性奇摄动问题边界层与边值的关系

利用匹配渐近展开法,讨论了一类二阶非线性奇摄动问题εy″＋yy＇＋xy＋y^2=0,x∈（0,1）,y（0）=α,y（1）=β,通过匹配方程的内层解、外部解及边界层解,得出解的层性态与边界条件的关系,并给出了解的渐近表示.     

一个新的Ekman泵公式在大气边界层Ekman垂直速度计算中的应用

利用GCM模式资料和Tan最新得到的具有复杂边界的层结大气边界层的Ekman泵公式,计算了大气边界层顶的Ekman垂直速度.结果表明,除青藏高原外,一般地区的大气边界层顶垂直速度的量级为每秒零点几厘米.在青藏高原地区,大气边界层顶的垂直速度可达每秒几厘米的量级,其分布类型在冬季和夏季显著不同,与该地区的盛行风系紧密相关.将新的Ekman泵公式的结果与经典的Ekman泵公式的计算结果进行比较,讨论了二者间的异同.     

定子磁链暂态对双馈感应电机接入系统小干扰稳定的影响

该文研究了定子磁链暂态过程对双馈感应电机接入系统的小干扰稳定的影响情况。首先建立了描述双馈感应电机电磁过程的8阶详细模型,并进一步推导了它的小干扰稳定的计算公式。根据Lyapunov特征值理论,对单个双馈感应电机经过传输线接入无穷大母线系统进行了数值分析。结果表明:无论是控制器参数变化还是传输线路电抗变化,6阶模型的稳定边界范围都比8阶模型更大。采用简化6阶模型不利于系统稳定性分析。     

边界摄动情况下一类二阶半线性椭圆型方程的边界层现象

本文考虑一类二阶半线性椭圆型方程的Dirichlet问题在边界摄动情况下的边界层现象。运用多参数展开法简捷地构造微分不等式,得到解的存在性及高阶一致有效渐近解。     

轴流泵叶片三维边界层计算

采用三维正交曲线坐标系下的动量积分方程预测轴流泵叶片上三维边界层的发展，并且分析了叶片曲率所产生的离心力和转轮旋转所产生的哥氏力对边界层发展的影响。     

带小参数的二阶微分方程奇异摄动边值问题

用微分不等式方法讨论了带小参数的二阶微分方程奇异摄动边值问题,并给出了边值问题的解的渐近估计。     

紊流边界层混凝作用探讨

通过对粘性流体紊流边界层的结构分析,得到混凝反应中关键性的控制因素,速度梯度和紊流切应力.讨论了这两个主要因素的变化规律,据此设计了更加理想的反应器结构,希望在混凝过程中能够对微粒的碰撞与聚合成长起到更好的作用.从根源上解释了紊流流场中速度梯度和旋涡的产生,试图把最近发展的涡旋混凝理论与传统的混凝理论进行统一.     

上海城市对大气边界层若干影响的初步分析

本文根据上海城市气候特征与大气污染防治课题组提供的上海城、郊同步观测的小球测风、低空探空和平衡球等资料,对上海城郊近地层和边界层内的湍强、R_i数、摩擦速度、下垫面粗糙度、风速廓线以及扩散参数等进行计算,并且采用城郊对比法进行分析和探讨.结果表明,上海城市对边界层动力和热力特征影响甚大,城市这个人为因素对边界层的影响不容忽视.     

平板层流速度边界层动态问题分析

从边界层动态微分方程出发，按照速度边界是层有关理论，推导出了边界层动态积分方程。在对边界层速度合理假设的基础上，求解了动态积分方程，给出了依时间和空间变化的边界层厚度响应函数。     

Wavelet-Galerkin Method for the Singular Perturbation Problem with Boundary Layers

IntroductionWaveletanalysisisadevelopmentofFourieranalysis.Asamathematicaltool,waveletshaveledtoexcitingapplicationsinsignalanalysis(soundandimages),quantumfieldtheoryandmanyotherfields.Inthecomputationalmathematicsfield,waveletanalysishasshownitsgreatpowerinthefastalgorithmsforintegraltransforms[1],thenumericalsolutionofPDEs[26],etc.Inthe1980's,theinterestinwaveletsgrewatanexplosiverate.BasedontheidealsofdilationsandtranslationsfromtheHaarbasis,Stromberg[7],Meyer[8],Lemarié[9]andBattle[1…     

一类非线性奇摄动边值问题的匹配解法

在一定条件下,讨论了一类二阶非线性奇摄动边值问题．利用匹配原理,针对3种情形分别得出了该类问题解的渐近展开式,推广了文[12]中的相应结果．