基于频谱突变分析的日冕物质抛射识别方法

提出一种从空间日冕观测图像中自动识别日冕物质抛射事件(CME)并分析计算事件特征参数的新方法,该方法主要包括以下3个步骤:通过预处理去除原始观测图像中的各种噪声;针对CME的视觉统计特性,利用频谱突变分析从预处理后的观测图像中准确分离CME像区域;基于区域协方差分析提取出角宽度、速度等CME特征参数.由于采用了频谱突变分析技术而非亮度增强检测技术来检测CME,该方法在识别多重和晦暗CME时具有更好的效果.     

日冕物理的辐射磁流体数值模拟研究

太阳的最外层大气日冕中发生着多种活动现象,如耀斑、日冕物质抛射、日珥、冕雨等.为了深入研究这些活动现象的非线性物理过程,通过辐射磁流体数值模拟,构建多维数值模型是主流的研究手段之一.数值模拟日冕等离子体的宏观行为需要求解磁流体力学、辐射、热传导和加热等物理过程.首先简要介绍了求解这些物理过程的主流数值算法.求解磁流体力学方程组的数值格式由网格界面值的重构方法、黎曼问题近似解法、磁场散度控制方法和时间积分方法等部分组成.之后,综述了辐射磁流体数值模拟对太阳活动区磁环、耀斑、日珥和冕雨等日冕中的活动现象的研究进展.     

珠江三角洲典型区水土中砷的分布

 为了解研究区水土中砷的来源及分布,采集地表水样5组、土壤样32组、地下水样14组进行分析。结果表明研究区地表水已受到砷污染。表层土壤(0~10 cm)中砷全量为198~274 mg/kg,平均全量为237 mg/kg,土壤中砷的形态分布以极难迁移的残渣态为主,各形态平均含量的顺序依次为残渣态＞弱有机结合态＞氧化物结合态＞碳酸盐态＞强有机结合态＞水溶态＞离子交换态。底层土壤(30~40 cm)中砷全量为115~281 mg/kg,平均全量为212mg/kg,土壤中砷的形态也以残渣态为主,土壤中砷的各种形态的平均含量顺序依次为残渣态＞弱有机结合态＞氧化物结合态＞碳酸盐态＞强有机结合态＞离子交换态＞水溶态,底层土壤中砷的各种形态的均量均低于表层土壤。包气带砷全量随深度增加先降低后升高,水溶态、离子交换态以及碳酸盐态的含量均随深度的增加而逐渐降低;而弱有机结合态、氧化物结合态、强有机结合态以及残渣态的含量随深度增加均呈无规律变化。地下水砷含量在00028~0021mg/L之间,均值为00114 mg/L,超标率达429％。地表污水灌溉下渗以及含水介质中原生砷的释放是研究区地下水砷的主要来源。     

直流辉光放电正柱区辉纹的形态演变

本文采用石英放电管,在氮、氩和氦气中进行直流辉光放电,改变气压、气体流速和放电电流,正柱区可形成辉纹,且形态逐渐演变.为研究辉纹形态演变,使用可连拍工业相机获得辉纹区照片,通过照片亮度计算分析辉纹亮度分布特点及其变化.结果表明:正柱区辉纹均呈现良好空间周期性;同时,有些放电条件下,辉纹亮度呈现从阴极到阳极逐渐衰减的周期性.与两种惰性气体相比,氮气中的辉纹最为清晰.因此,以氮气辉纹为例,定量研究了辉纹形态(辉纹波长和衰减系数)随放电条件的演变,结果发现:辉纹波长与放电电流密度的对数值几乎呈线性关系;而与气压和气体流速的相关性更为复杂.与此类似,在不同气压和流速条件下,辉纹衰减系数随放电电流的变化趋势也相当一致.     

SOLARC日冕磁场反转特征探讨

随着近来红外探测技术的发展, 对日冕磁场的高灵敏度测量方法已成为可能．在常规红外观测中的一个紧要任务就是要解释各种不同的Stokes信号分别能代表什么样的日冕磁场. 采用完全Stokes参量的谱线轮廓, 首次成功地展示了位于光球上的一个简单且稳定黑子的日冕磁场结构. 文中进一步指出基于非完全偏振数据的分析可能会导致结论非唯一. 如从圆偏振数据得到的磁通量反转特征, 可能对应日冕中的一个或多个拱形环系前凸或后凸的顶点部分. 这一结论比之前人们想像的情形更为复杂. 为了准确地找出日冕红外辐射源区空间位置, 我们需要综合利用和分析圆偏振和线偏振数据.     

利用同亮度像点的航空图像像移复原研究

在航空遥感、航空侦察等领域,需要得到目标的高分辨率图像。而像移直接影响了成像质量、降低了空间分辨率。本文提出,通过对具有同亮度区域目标先进行像点亮度确定,再进行外推计算,即可对像移图像进行复原。这对于使用现有的不带像移补偿机构的航空相机获取高分辨率图像具有十分重要的意义。     

论两极对立与相互作用

本文通过对物理学中两极对立与相互作用的研究，从哲学角度阐述了吸引和排斥只是对立两极的表现形态，而相互作用则是其质的反映．分量等值、总量守恒是相互作用过程的一般规律，而这个规律的特点、性质具有统计的意义．     

极轨气象卫星NOAA AVHRR数据的高精度定位

针对极轨气象卫星 Ｎ Ｏ Ａ Ａ Ａ Ｖ Ｈ Ｒ Ｒ 数据的高精度定位,提出了一种从直接定位、导航定位、几何精校正三方面综合考虑的方案。该方案通过建立精确的卫星运动轨道模型、卫星摄动模型,采用对称椭球体的地球形态模型和融入卫星姿态的地面扫描点位置的计算方法,使直接定位精度达到３ 个像元。通过定量分析影响导航定位精度的主要因素,提出了融合卫星时间漂移校正、调整卫星轨道根数和估算卫星姿态偏差的导航定位新算法。在导航定位和几何精校正中,利用具有足够定位精度的１∶１００ 万数字地图数据和高分辨率 Ｌａｎｄｓａｔ Ｔ Ｍ 图像,提取地面控制点和控制块,使 Ａ Ｖ Ｈ Ｒ Ｒ 数据导航定位精度达到１ 个像元,几何精校正定位精度达到０５ 个像元     

雪的面目

在赤道,一位小学老师努力地给儿童说明“雪”的形态,但不管他怎么说,儿童也不能明白。老师说：雪是纯白的东西。儿童就猜测：雪是像盐一样。老师说：雪是冷的东西。儿童就猜测：雪是像冰淇淋一样。老师说：雪是粗粗的东西。儿童就猜测：雪是像砂子一样。     

日冕磁场与等离子体综合探测望远镜

太阳物理研究亟待解决的重大核心问题包括了太阳爆发、日冕加热和太阳风加速等机制.揭示这些现象背后的发生和发展规律将为空间灾害性天气预报和相关天体物理研究提供精确有效的模型.建议设计的日冕磁场和等离子体综合探测望远镜(COronal Magnetism and Plasma ASsembled Scopes,COMPASS)由口径为1.26 m大型日冕磁场探测望远镜(COronal Magnetism Probing Telescope,COMPT)、口径为0.30 m中型二维成像光谱日冕仪(Two-dimensional Spectroscopic Diagnosis Coronagraph,TSDC)以及安装在COMPT上的0.09 m的口径小型Lyot日冕仪(COMPASS-SC)组成.COMPT主攻高度范围0.05–0.65太阳半径(R_(Sun))内矢量磁场和热动力学参量精确测量,TSDC聚焦在(0.10–1.50)R_(Sun)高度范围内对日冕等离子体的各项物理参量进行诊断以及提供全方位日冕结构和演化监测,而COMPASS-SC为COMPT提供其积分视场观测区域定位以及大视场日冕演化监测.这一组3台日冕仪功能互补互联,集中测量(0.05–1.50)R_(Sun)高度范围的矢量磁场和热动力学参量分布及其演化.由于其创新性设计,COMPT建成后不仅将成为国际上最大口径的折射式望远镜,也将成为第一台具有高偏振测量精度的多条谱线同时偏振成谱成像的日冕仪,而TSDC首次将白光偏振成像和谱线二维(线偏振)成像光谱测量功能集于一身.本文首先概括了COMPASS的科学需求和国外仪器的发展态势,然后从总体设计思想和理念、光机电初步设计等方面对COMPASS进行介绍,并特别阐述了围绕科学目标而做出的创新性仪器设计.     

Coronal structure and brightness profile of the total solar eclipse on August 1, 2008

Solar corona is the outermost part of the solar atmosphere. Coronal activities influence space environment between the Sun and the Earth, space weather and the Earth itself. The total solar eclipse （TSE） is the best opportunity to observe the solar corona on ground. During the TSE 2008, a series of images of the corona and partial eclipse of solar disk were obtained using telescope and CCD camera. After image processing, preliminary results of coronal structure are given, and radial brightness profiles of the corona in directions of pole and equator of the Sun are measured. Though in solar activity minimum, the shape and structure of the corona are not symmetry. The equatorial regions are more extent than the polar one, and there are also larger differences between the east and west equatorial regions and between the south and north polar regions. Coronal streamers on east side of the equator, particularly the largest one in east-south direction, are very obvious. The coronal plume in south polar region consists of more polar rays than that in north polar region. These structures are also shown in other observations and data of SOHO. The radial brightness profiles in directions of pole and equator are similar to those of the Van de Hulst model in solar minimum, but there are a few differences due to coronal activity, which is shown in the isophote map of the corona.     

冕流的白光偏振

研究了日冕白光冕流的偏振特性，包含：典型冕流的偏振度随日心距增大的变化；冕流白光高度在同一日心距处沿日面位置角的分布；不同日面纬度处冕流的偏振器；冕流中偏振亮度分布的不均匀性。     

冕洞边界区磁结构的探讨

摘要用Hell083nm单色像上的极区、低纬冕洞的边界,确定Fe]532.4nm纵向场全日面磁图上对应的极,低纬冕洞的边界.对光球上极、低纬冕洞边界足根连线范围内外的磁场强度,磁极性、磁场几何位形进行了分析讨论.观测结果表明t就极无涧大尺度范围来看,是单极开放场I就48h时标的加强磁结构来说,以开放场为主的情况下,有开放场与闭合场栩混杂的情况.就同时的极冕洞与低纬度冕洞边界足根连线附近磁场位形相比较,差别是明显的.     

太阳常数的变化和日食对旱涝影响的机制

本文用Lorenz的对流方程组和大气环流方程组说明太阳常数的变化和日食对旱涝影响的机制,并对用日食相似年预报旱涝的方法提出改造意见,而用实例予以证明。     

A review of recent studies on coronal dynamics: Streamers, coronal mass ejections, and their interactions

In this article I present a review of recent studies on coronal dynamics, including research progresses on the physics of coronal streamers that are the largest structure in the corona, physics of coronal mass ejections (CMEs) that may cause a global disturbance to the corona, as well as physics of CME-streamer interactions. The following topics will be discussed in depth: (1) acceleration of the slow wind flowing around the streamer considering the effect of magnetic flux tube curvature; (2) physical mechanism accounting for persistent releases of streamer blobs and diagnostic results on the temporal variability of the slow wind speed with such events; (3) force balance analysis and energy release mechanism of CMEs with a flux rope magnetohydrodynamic model; (4) statistical studies on magnetic islands along the coronal-ray structure behind a CME and the first observation of magnetic island coalescence with associated electron acceleration; and (5) white light and radio manifestations of CME-streamer interactions. These studies shed new light on the physics of coronal streamers, the acceleration of the slow wind, the physics of solar eruptions, the physics of magnetic reconnection and associated electron acceleration, the large-scale coronal wave phenomenon, as well as the physics accounting for CME shock-induced type II radio bursts.     

Magneto-thermal convection in solar prominences

Coronal cavities are large low-density regions formed by hemispheric-scale magnetic flux ropes suspended in the Sun's outer atmosphere. They evolve over time, eventually erupting as the dark cores of coronal mass ejections. Although coronal mass ejections are common and can significantly affect planetary magnetospheres, the mechanisms by which cavities evolve to an eruptive state remain poorly understood. Recent optical observations of high-latitude 'polar crown' prominences within coronal cavities reveal dark, low-density 'bubbles' that undergo Rayleigh-Taylor instabilities to form dark plumes rising into overlying coronal cavities. These observations offered a possible mechanism for coronal cavity evolution, although the nature of the bubbles, particularly their buoyancy, was hitherto unclear. Here we report simultaneous optical and extreme-ultraviolet observations of polar crown prominences that show that these bubbles contain plasma at temperatures in the range (2.5-12)?×?10(5) kelvin, which is 25-120 times hotter than the overlying prominence. This identifies a source of the buoyancy, and suggests that the coronal cavity-prominence system supports a novel form of magneto-thermal convection in the solar atmosphere, challenging current hydromagnetic concepts of prominences and their relation to coronal cavities.     

Three-dimensional magnetic field topology in a region of solar coronal heating

Flares and X-ray jets on the Sun arise in active regions where magnetic flux emerges from the solar interior amd interacts with the ambient magnetic field. The interactions are believed to occur in electric current sheets separating regions of opposite magnetic polarity. The current sheets located in the corona or upper chromosphere have long been thought to act as an important source of coronal heating, requiring their location in the corona or upper chromosphere. The dynamics and energetics of these sheets are governed by a complex magnetic field structure that, until now, has been difficult to measure. Here we report the determination of the full magnetic vector in an interaction region near the base of the solar corona. The observations reveal two magnetic features that characterize young active regions on the Sun: a set of rising magnetic loops and a tangential discontinuity of the magnetic field direction, the latter being the observational signature of an electric current sheet. This provides strong support for coronal heating models based on the dissipation of magnetic energy at current sheets.     

中国古代正史31次日全（环）食记录的研究

古代日全（环）食记录一般表示为“日有食之,既”。本收集整理了中国古代正史３１次日全（环）食记录,用现代４种不同计算日食的方法,给出了当时国都等地的见食情况－食甚时刻和食分;同时对这些全（环）食资料的可靠性进行了分析和评判,并试图给出一个较为合理料,方可进一步用于地球自转长期变化等课题的研究。