On the Evolution of the Lower Energy Cutoff of Nonthermal Electrons in Solar Flares

1 INTRODUCTION Gan, Li and Chang (2001a) proposed a quantitative method to obtain the lower energycutoff (Er) of power-law electrons from the observed broken-down double power-law hard Xray spectrum. Most recently Can et al. (2002) improved the method and let it be moreself-consistent. They applied their improved method to the 54 hard X-ray events observed withBATSE/CGRO and acquired more general results in comparison with those obtained by Canet al. (2001b). Despite the data is rel…     

THREE-DIMENSIONAL BAROCLINIC NUMERICAL SIMULATION OF THE SOUTH CHINA SEA CIRCULATION＇S SEASONAL CHARACTERISTICS II. MIDDLE AND DEEP CIRCULATION

A three-dimensional baroclinic shelf sea model‘ s numerical simulation of the South China Sea (SCS) middle and deep layer circulation structure showed that: 1. In the SCS middle and deep layer, a seulhward boundary current exists along the east shore of the Indo-China Peninsula all year long.A cyclonic eddy (gyre) is formed by the current in the above sea areas except in the middle layer in spring, when an anticyclonic eddy exists on the eastern side of the current. In the deep layer, a larges-cale anticyclonic eddy often exists in the sea areas between the Zhongsha Islands and west shore of southern Luzon Island. 2. In the middle layer in snmmer and autumn, and in the deep layer in autumn and winter, there is an anticyclonic eddy (gyre) in the northeastern SCS, while in the middle layer in winter and spring, and in the deep layer in spring and snmmer, there is a cyclonic one. 3. In the middle layer,there is a weak northeastward current in the Nansha Trough in spring and snmmer, while in autumn and winter it evolves inl~ an anticyclonic eddy ( gyre), which then spreads westward l~ the whole western Nansha Islands sea areas.     

An Impulsive Heating Model for the Evolution of Coronal Loops

It was suggested by Parker that the solar corona is heated by many small energy release events generally called microflares or nanoflares. More and more observations showed flows and intensity variations in nonflaring loops. Both theories and observations have indicated that the heating of coronal loops should actually be unsteady. Using SOLFTM (Solar Flux Tube Model), we investigate the hydrodynamics of coronal loops undergoing different manners of impulsive heating with the same total energy deposition. The half length of the loops is 110 Mm, a typical length of active region loops. We divide the loops into two categories: loops that experience catastrophic cooling and loops that do not. It is found that when the nanoflare heating sources are in the coronal part, the loops are in non-catastrophic-cooling state and their evolutions are similar. When the heating is localized below the transition region, the loops evolve in quite different ways. It is shown that with increasing number of heating pulses and inter-pulse time, the catastrophic cooling is weakened, delayed, or even disappears altogether.     

一种高精度数字地温测量系统

介绍了采用高Ｑ值石英测温晶体组成的高精度数字温度传感器。该传感器在高分辨率和宽温度范围内频率随温度的变化呈线性关系，其主要特点是抗干扰能力强及数字量输出。阐述了由单片机组成的测量系统，它对传感器输出的地温频率信号进行信息处理、数值转换并显示、打印及远距离传输。该系统除用于地温前兆观测外，还用于高精度机械加工的环境温度测量。     

FORMATION MECHANISM AND SPATIAL PATTERN OF URBAN AGGLOMERATION IN CENTRAL JILIN OF CHINA

1 INTRODUCTION Urban agglomeration researches originated from the concern about the city cluster in the developed areas of western countries. The modern researches have been extended to the specific areas. HALL (2001) summa- rized the generality and difference of urban metropoli- tans in Europe, and analyzed the spatial structure of dif- ferent areas. NAUDE and KRUGELL (2003) analyzed the spatial development of urban agglomeration in South Africa, and thought that the size of the p…     

关于太阳白光耀斑连续发射起源的讨论

白光耀斑研究近年来获得较大进展，对其连续发射起源机制目前流行三种解释．一是耀斑形成过程中所产生的色球凝聚[1-3]，二是非热粒子注入大气致氢原子非热激发和电离[4-6]，三是色球强加热所引起的对大气深层的辐射反加热[7]．这三类解释具有一个共性，即除了自身直接对连续谱     

一种后现代的叙事模式--东西小说叙事策略探微

东西的小说创作,尤其是20世纪90年代中期以后的相当一部分作品,在主题思想和叙述策略上均具有鲜明的后现代倾向,足以形成其独特的艺术方式.以后现代主义文学与叙事学的相关理论,从东西小说创作的叙事手法和叙述语言等方面出发,试图对东西小说独特的叙事艺术予以解读.     

Global Lagrangian Atmospheric Dispersion Model

The Global Lagrangian Atmospheric Dispersion Model (GLADIM) is described. GLADIM is based on the global trajectory model, which had been developed earlier and uses fields of weather parameters from different atmospheric reanalysis centers for calculations of trajectories of air mass that include trace gases. GLADIM includes the parameterization of turbulent diffusion and allows the forward calculation of concentrations of atmospheric tracers at nodes of a global regular grid when a source is specified. Thus, GLADIM can be used for the forward simulation of pollutant propagation (volcanic ash, radionuclides, and so on). Working in the reverse direction, GLADIM allows the detection of remote sources that mainly contribute to the tracer concentration at an observation point. This property of Lagrangian models is widely used for data analysis and the reverse modeling of emission sources of a pollutant specified. In this work we describe the model and some results of its validation through a comparison with results of a similar model and observation data.     

FAST30m模型L-波段馈源的设计、制作和性能测试

叙述了FAST（500m口径球面射电望远镜）30m模型L-波段馈源的设计、制作和性能测试过程。馈源的设计仿真使用了HFSS软件，并选用纸板或塑料板和铝箔胶带，通过手工操作完成馈源制作。馈源的性能通过测试表明满足FAST30m模型天文观测的需要。文中采用的HFSS软件仿真及手工制作馈源的方式不失为形式简单的馈源的模型制作的一种快速、经济和有效的方法。这种方法对相近的工作有一定的参考价值。     

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