“地表形态的塑造、自然地理环境的整体性与差异性”训练     

马海波  殷礼高 《地理教学》2011,(18):56-61

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1960-2009年新疆渭干河流域蒸发皿蒸发量变化特征   总被引：1，自引：0，他引：1  

卢磊  乔木  周生斌  唐金  闫俊杰 《地理科学进展》2011,30(3):306-312

根据新疆气象局地面观测资料,整理出渭干河流域1960-2009年蒸发皿蒸发量资料,运用线性趋势估计、距平与累积距平、滑动t检验、小波分析、灰色预测等方法,对蒸发皿蒸发量的变化趋势、周期特征、突变特征及未来趋势进行了分析。结果表明:①50年来,渭干河流域蒸发皿蒸发量有升有降,总体上呈波动式减少的趋势,其变化倾向率为-19.72 mm/10a,通过了0.05的显著性检验。累积距平曲线的变化趋势显示,年蒸发皿蒸发量以1987年和2004年为转折点,前期偏多,中期偏少,后期偏多。②年蒸发皿蒸发量在1987年发生了由多到少的突变,在2004年发生了由少到多的突变,突变类型比较复杂,是均值突变和转折突变两种突变类型的组合。③蒸发皿蒸发量在50a的时间序列中存在8a、17a和20a的周期。在8a的时间尺度上,年蒸发皿蒸发量序列经历了7个偏多期和6个偏少期;在17a的时间尺度上,经历了2个偏多期和2个偏少期;在20a的时间尺度上,经历了1个偏少期和2个偏多期。④利用建立的灰色预测GM(1,1)模型对渭干河流域蒸发皿蒸发量进行了预测,发现模型的可靠性高,预测结果准确,年蒸发皿蒸发量在未来3年将出现增加的趋势。  相似文献   

移动测量技术及其在数字城市中的应用     

伍百发 《国土资源导刊(湖南)》2011,(6):90-91

本文介绍了移动测量系统的组成及其基本工作原理,详细阐述了该系统的关键技术及其应用.扼要介绍了数字城市建设与三维数字地图的相关内容,就移动测量系统在数字城市建设中的应用及其技术和方法进行了探讨和研究,并对其发展前景进行了展望.  相似文献   

Estimating Photometric Redshifts with Artificial Neural Networks and Multi-Parameters     

Li-Li Li Yan-Xia Zhang Yong-Heng Zhao Da-Wei Yang 《中国天文和天体物理学报》2007,7(3):448-456

We calculate photometricredshifts from the Sloan Digital Sky SurveyData Release 2 (SDSS DR2) Galaxy Sample using artificial neural networks (ANNs). Different input sets based on various parameters (e.g. magnitude, color index, flux information) are explored. Mainly, parameters from broadband photometry are utilized and their performances in red- shift prediction are compared. While any parameter may be easily incorporated in the input, our results indicate that using the dereddened magnitudes often produces more accurate pho- tometric redshifts than using the Petrosian magnitudes or model magnitudes as input, but the model magnitudes are superior to the Petrosian magnitudes. Also, better performance re- sults when more effective parameters are used in the training set. The method is tested on a sample of 79346 galaxies from the SDSS DR2. When using 19 parameters based on the dereddened magnitudes, the rms error in redshift estimation is σz = 0.020184. The ANN is highly competitive tool compared to the traditional template-fitting methods when a large and representative training set is available.  相似文献   

65 cm水平式望远镜静态指向模型     

平一鼎  张晓祥  鲁春林 《天文学报》2006,47(2):224-230

由于传统的静态指向模型对于水平式装置存在法方程条件差的困难,针对紫金山天文台盱眙站65 cm水平式空间碎片望远镜,基于真实的可能产生误差的来源建立了独特的静态指向模型,使模型参数具有明确的物理意义,从而基本剔除了望远镜的系统误差,大大提高了该望远镜的指向精度,达到了4”．  相似文献   

X-Wind模式下对宁强碳质球粒陨石光学特征的重新认识     

谈迎  徐伟彪 《天文学报》2006,47(2):153-165

宁强碳质球粒陨石非偏振光、偏正光、反射光下的矿物、组构的光学特征中蕴藏着丰富的有关太阳星云演化初期不挥发组分吸积时的动力、温度、压力、介质信息．在宁强陨石双面抛光片中,矿物组构混杂堆积的构造反映了太阳星云吸积盘上极弱的机械动力环境和近物源吸积作用;外形不规则,边缘参差的矿物集合体和矿物碎片应该是抛落时碰撞破碎的球粒,这些球粒形成于X-Wind模式中的X-区,并被双极喷流抛落到太阳星云的不同部位;在透射光下,从宁强陨石中首次发现存在有玻璃、结晶、及气相包裹体,它们可以反映出太阳星云演化过程中的物质成分、热力学、动力学信息,应该引起重视．实验观察中还发现同一个球粒中锯齿状缝合线连接的橄榄石栅条和橄榄石颗粒．诸多现象需要理论物理、天体物理观察和天体化学实验的科学家共同努力去探讨.X-Wind模式中许多细节有待天体化学实验去检验、补充和完善．  相似文献   

对"文[1,2]"评论的答复     

宋慕陶  张延安 《天文学报》2006,47(1):67-68

对“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”一文,提出一些看法和补充,以增进对无力场计算太阳磁场问题的进一步的认识．  相似文献   

Mira Symbiotic Stars     

Guo-Liang Lü 《中国天文和天体物理学报》2007,7(1):101-110

1 INTRODUCTION Symbiotic stars (SSs) are interacting binaries consisting of a cool giant, a hot compact companion and an H II region (Berman 1932; Boyarchuk 1967; Boyarchuk 1968). The cool component is a red giant (RG) that belongs either to the first gia…  相似文献   

Disk-Corona Model in Active Galactic Nuclei： an Observational Test     

Fang Yang Chen Hu Yan-Mei Chen Jian-Min Wang 《中国天文和天体物理学报》2007,7(3):353-363

We compiled a sample of 98 radio-quiet active galactic nuclei observed by ASCA, Chandra, XMM-Newton, INTEGRAL and Swift with the aim of testing the formation of hot corona and the magnetic shear stress operating in a disk-corona system. We found a strong correlation between the hard X-ray luminosity, bolometric luminosity L Bol and Eddington luminosity LEdd, in the sense that the fraction f of hard X-ray to the bolometric luminosity is inversely proportional to the Eddington ratio. This correlation favors the shear stress tensor being of the form of trφ∝ Pgas, with which the disk-corona structure is stable.  相似文献   

A New Formulation for General Relativistic Force-Free Electrodynamics and Its Applications     

Cong Yu National Astronomical Observatories/Yunnan Observatory  Chinese Academy of Sciences  Kunming   《中国天文和天体物理学报》2007,7(6):743-756

We formulate the general relativistic force-free electrodynamics in a new 3 1 language. In this formulation,when we have properly defined electric and magnetic fields,the covariant Maxwell equations could be cast in the traditional form with new vacuum con-stitutive constraint equations. The fundamental equation governing a stationary,axisymmet-ric force-free black hole magnetosphere is derived using this formulation which recasts the Grad-Shafranov equation in a simpler way. Compared to the classic 3 1 system of Thorne and MacDonald,the new system of 3 1 equations is more suitable for numerical use for it keeps the hyperbolic structure of the electrodynamics and avoids the singularity at the event horizon. This formulation could be readily extended to non-relativistic limit and find applica-tions in flat spacetime. We investigate its application to disk wind,black hole magnetosphere and solar physics in both flat and curved spacetime.  相似文献