A Preliminary Research on the Development of the Hard X-ray Imaging Telescope     

ZHENG Chun-xiao  CAI Ming-sheng  HU Yi-ming  HUANG Yong-yi  GONG Yi-zhong 《Chinese Astronomy and Astrophysics》2014

The hard X-ray imaging telescope based on the Fourier transform imaging technique is introduced. The double-layer parallel gratings are used to make the modulation and coding on the light emerging from a celestial X-ray source, the modulated light is acquired, to make the optoelectronic conversion by scintillation crystal detectors, and ?nally read out by the electronic system. The modulation collimator X-ray telescopes can be divided into two types: the spatial modulation and temporal modulation. The temporal modulation system requires the scanning motion of the detector system, but the spatial modulation system requires no motion. The technology of grating fabrication is investigated, and the basic structure design of the collimators is given. The principal compo- nents of the prototype hard X-ray imaging telescope of spatial modulation type are successfully developed, including the 8 CsI crystal detector modules (contain- ing photomultipliers or PMTs), 8-channel shaping ampli?ers (two of them are prepared for experiments), and the data acquisition system. And the preliminary test results of the electronic system are also given.  相似文献   

Variations mechanism in entropy of wave height field and its relation with thermodynamic entropy     

郭佩芳侯一筠  钱成春周良民 《中国海洋湖沼学报》2006,24(1):65-68

  相似文献   

太阳光球磁通量南北不对称性研究     

宋文彬  汪景琇  马霞 《天文学报》2005,46(1):19-26

运用统计方法系统研究了1978-2002年太阳光球磁通量南北不对称性变化特征，发现其与太阳活动周有关．不对称值在太阳活动极小年要明显高于太阳活动极大年，并且磁通量变化总是由上升段的北半球占优逐渐过渡到下降段的南半球占优．另外运用小波变换方法详细讨论了这种不对称性变化可能存在的周期信息．  相似文献   

用CE-318太阳光度计资料研究银川地区气溶胶光学厚度特性   总被引：34，自引：9，他引：25  

刘玉杰  牛生杰  郑有飞 《南京气象学院学报》2004,27(5):615-622

根据CE-318数据,利用Bouguer定律计算了银川地区的大气气溶胶光学厚度,并分析其变化特征。结果表明,该地区大气气溶胶光学厚度具有明显的日变化和季节变化。日变化有4种类型：1)变化相对稳定;2)整体上呈上升的趋势;3)早晚小,中午大;4)早晨09-11时出现峰值,其他时间变化较小。季节变化则是冬、春季节大,秋季次之,夏季最小;春季大气中的主要成分是沙尘,冬季大气的主要成分是人类活动排放的颗粒物,夏季由于降水多,气溶胶数浓度较低,气溶胶光学厚度较小。  相似文献   

关于"太阳线性无力场评注和快速傅氏分析法的应用"的评论     

李柱恒  颜毅华  宋国乡 《天文学报》2006,47(1):63-66

“太阳线性无力场评注和快速傅氏分析法的应用”一文对太阳线性无力场的工作做了一些评注,在此基础上对快速傅立叶方法的应用提出了改进的计算方法．该文的某些观点值得商榷,有必要对其中存在的问题予以澄清．另外,对该文关于快速傅氏分析法的工作从理论的角度提出看法．  相似文献   

计算转换参数提高手持式GPS接收机定位精度的方法与探讨     

乔天荣 《测绘与空间地理信息》2012,35(4):97-99

通过在矿区施测的静态GPS控制测量,根据实际不同的坐标系工程用图需要,在矿区内均匀选择三个以上公共点的两套坐标,探讨对手持式GPS接收机求取其转换参数的方法,采用五参数转换法,求出转换参数,然后在手持GPS接受机上设置五参数来提高定位精度.  相似文献   

A Statistical Study on the Geomagnetically Induced Current Events Driven by Earth-directed Full-Halo Coronal Mass Ejections     

Wang Kai-Rang  Lin Jun  Liu Lian-Guang  Liu Chun-Ming  Gao Guan-Nan 《Chinese Astronomy and Astrophysics》2012

Solar activities can cause the anomalies of electric power transmission systems, especially, for an extra-long distance transmission system. Using the data of coronal mass ejection (CME) from SOHO/LASCO (Solar and Heliospheric Observatory/Large Angle and Spectrometric Coronagraph), and the data of the geomagnetically induced current (GIC) and geomagnetic storm from the North China Electric Power University and Finnish Meteorological Institute, respectively, we analyze some important observational features and physical properties of the earth-directed halo CMEs associated with the GIC events. After classifying the observed halo CMEs according to their symmetry, it is found that the halo CMEs associated with GIC events are mainly the 3 types: completely symmetric, brightness-asymmetric, and outline-asymmetric. The geomagnetically induced current events driven by the three different types of halo CMEs have different characteristics in the intensity, duration, and period. We ?nd that the brightness-asymmetric halo CMEs are most likely to cause the major damage to the transmission systems. And that the geomagnetically induced current has also a good correlation with the time variation of geomagnetic ?eld.  相似文献   

太阳米波和分米波Ⅱ型、Ⅲ型射电暴及其精细结构观测研究进展     

高冠男  林隽  汪敏  谢瑞祥 《天文学进展》2012,30(1):35-47

太阳米波和分米波的射电观测是对太阳爆发过程中耀斑和日冕物质抛射现象研究的重要观测手段。米波和分米波的太阳射电暴以相干等离子体辐射为主导,表现出在时域和频域的多样性和复杂性。其中Ⅱ型射电暴是激波在日冕中运动引起电磁波辐射的结果。在Ⅱ型射电暴方面,首先对米波Ⅱ型射电暴的激波起源问题和米波Ⅱ型射电暴与行星际Ⅱ型射电暴的关系问题进行了讨论;其次,结合Lin-Forbes太阳爆发理论模型对Ⅱ型射电暴的开始时间和起始频率进行讨论:最后,对Ⅱ型射电暴信号中包含的两种射电精细结构,Herringbone结构(即鱼骨结构)和与激波相关的Ⅲ型射电暴也分别进行了讨论。Ⅲ型射电暴是高能电子束在日冕中运动产生电磁波辐射的结果。在Ⅲ型射电暴方面,首先介绍了利用Ⅲ型射电暴对日冕磁场位形和等离子体密度进行研究的具体方法;其次,对利用Ⅲ型射电暴测量日冕温度的最新理论进行介绍;最后,对Ⅲ型射电暴和Ⅱ型射电暴的时间关系、Ⅲ型射电暴和粒子加速以及Ⅲ型射电暴信号中包含的射电精细结构(例如斑马纹、纤维爆发及尖峰辐射)等问题进行讨论并介绍有关的最新研究进展。  相似文献   

云台便携式光电光度计以及天光背景的测定方法     

张涛  柳光乾  李志 《天文研究与技术》2008,5(1):66-73

首先详细介绍了云台便携式光电光度计的结构和设计思想,然后叙述了如何利用云台便携式光电光度计测定天光背景.  相似文献   

The Accuracy of Atmospheric Models in Solar Maximum Years Checked with the Data of CHAMP Accelerometer     

Hong-Bo Wang  Chang-Yin Zhao 《Chinese Astronomy and Astrophysics》2008

A method of processing the data obtained with the CHAMP satelliteborne accelerometer is introduced. Through an analysis of the data the fault in the x-axis of the instrument is verified. We examined the accuracy of the atmospheric models in solar maximum years with the accelerometer data obtained from 2001 to 2002 and the inversion of the atmospheric density from the tangential non-gravitational acceleration. Then from a statistical analysis of the errors of the models, DTM94 and MSIS90, we obtained the following quantitative conclusions. During the solar maximum years the error of DTM94 is 30% to 35%, and that of MSIS90 is smaller at 25% to 30%. The greatest difference between the two models is about 10%.  相似文献