塔里木河下游胡杨径向生长量对生态输水的响应   总被引：5，自引：0，他引：5  

安红燕  叶茂  徐海量  禹朴家 《中国沙漠》2011,30(4):957-962

 以塔里木河下游的胡杨径向生长量为研究对象,借鉴树木年轮水文学的方法,采用单因素方差分析方法,从数理统计学的角度分析了胡杨径向生长量对生态输水的响应过程。结果表明: ①距离河道300 m范围内,生态输水前后及输水期间各年份之间,胡杨的径向生长量在0.001的水平上差异极显著,胡杨对生态输水的响应非常积极; ②距离河道300 m范围外,胡杨的径向生长量在0.05的水平上差异不显著,胡杨对生态输水的响应不积极; ③线性的生态输水只是缓解了河道附近植被的衰退,改善了局部生态环境,却无法从根本上缓解整个塔里木河下游生态环境的恶化,塔里木河下游的生态环境呈现出局部改善、整体恶化的趋势。  相似文献   

集对分析径向基函数神经网络预测模型   总被引：1，自引：0，他引：1  

陈晶  王文圣  李跃清 《水文》2011,31(2):11-14

将集对分析与径向基函数神经网络结合,提出了集对分析径向基函数神经网络预测模型。模型思路是将研究对象t-1时和t时的影响因子集构造为集对并计算联系度,由联系度的同一度、差异度、对立度及研究对象t-1时的值为输入,研究对象t时的值为输出,构建径向基函数神经网络。以年径流预测为例研究表明,模型结构清晰、步骤明确、预测精度较高,为集对分析应用于水文预测提供了新思路。  相似文献   

南黄海辐射沙脊群西洋水道污水输移扩散研究   总被引：1，自引：0，他引：1  

周智鹏  陶建峰  张长宽  徐凡  姚静 《海洋通报》2015,34(1):65-71

采用沿深平均二维数值模型对南黄海辐射沙脊群西洋海域的潮流场和物质扩散场进行了模拟,计算和分析了大潮情况下海域5 m、7 m和10 m 3种水深(理论基准面下)排放位置处达标污水输移扩散的范围及分布规律。结果表明,污水排入海后,会很快被稀释,各排放位置200和500稀释度等值线包络面积均较小,且包络面积随水深增加有明显变小的规律。拟合了不同污水排放量对应的200和500稀释倍数包络面积,发现两者呈良好的幂级数关系。  相似文献   

条子泥一期工程对条子泥发育影响及工程防护措施   总被引：2，自引：0，他引：2  

陈才俊  徐向红 《海洋工程》2015,33(5):105-112

通过历史和现场观测资料并结合遥感卫片资料,对条子泥匡围一期工程两年多的建设过程中,由工程所引起对条子沙洲西大港、东大港、条鱼港等主要的潮沟,及相应的潮盆系统和二分水的剧烈变化进行了分析研究,总结了潮沟摆动治理经验。治理方法主要为丁坝群结合砼连锁块镇压排布防护技术等。  相似文献   

比例射线移位算法的改进及其应用     

刘晴  郭庆胜  龙毅 《测绘工程》2015,(12):68-71

点状要素群移位的比例射线算法能够较好地保持移位后点群的空间分布模式。文中从农村居民地群移位的实际要求出发,对比例射线移位算法进行了改进:首先考虑居民地面积的不同大小对移位的影响;其次,设计比例射线移位的迭代方法;最后对于非常邻近的居民地群的移位,采用"微小"移位方法。通过实验验所改进的算法是有效的。  相似文献   

径向基神经网络GPS高程转换方法     

杨金玲  曹先革  曹先密 《地理空间信息》2010,8(6):65-66,70

针对GPS高程转换问题,给出了基于径向基神经网络转换GPS高程的模型。用实际观测数据对该模型进行了试验,结果表明,用径向基神经网络转换GPS高程精度高于二次拟合法和BP神经网络法。径向基神经网络能够有效克服BP神经网络局部极小值的缺点,并且具有较高的收敛速度,在GPS高程转换方面具有广阔应用前景。  相似文献   

Time‐series high‐resolution spectroscopy and photometry of ε Aurigae from 2006–2013: Another brick in the wall     

K. G. Strassmeier  M. Weber  T. Granzer  L. Schanne  J. Bartus  I. Ilyin 《Astronomische Nachrichten》2014,335(9):904-934

We present continuous and time‐resolved R = 55 000 optical échelle spectroscopy of ε Aurigae from 2006–2013. Data were taken with the STELLA Echelle Spectrograph of the robotic STELLA facility at the Observatorio del Teide in Tenerife. Contemporaneous photometry with the Automatic Photoelectric Telescopes at Fairborn Observatory in Arizona is presented for the years 1996–2013. Spectroscopic observations started three years prior to the photometric eclipse and are still ongoing. A total of 474 high‐resolution échelle spectra are analyzed and made available in this paper. We identify 368 absorption lines of which 161 lines show the characteristic sharp disk lines during eclipse. Another 207 spectral lines appeared nearly unaffected by the eclipse. From spectrum synthesis, we obtained the supergiant atmospheric parameters T_eff = 7395 ± 70 K, log g ≈ 1, and [Fe/H] = +0.02 ± 0.2 with ξ_t = 9 km s^–1, ζ_RT = 13 km s^–1, and v sin i = 28 ± 3 km s^–1. The residual average line broadening expressed in km s^–1 varies with a period of 62.6 ± 0.7 d, in particular at egress and after the eclipse. Two‐dimensional line‐profile periodograms show several periods, the strongest with ≈110 d evident in optically thin lines as well as in the Balmer lines. Center‐of‐intensity weighted radial velocities of individual spectral lines also show the 110‐d period but, again, additional shorter and longer periods are evident and are different in the Balmer lines. The two main spectroscopic Hα periods, ≈ 116 d from the line core and ≈ 150 d from the center‐of‐intensity radial velocities, appear at 102 d and 139 d in the photometry. The Hβ and Johnson V I photometry on the other hand shows two well‐defined and phase‐coherent periods of 77 d and 132 d. We conclude that Hα is contaminated by changes in the circumstellar environment while the Hβ and V I photometry stems predominantly from the non radial pulsations of the F0 supergiant. We isolate the disk‐rotation profile from 61 absorption lines and found that low disk eccentricity generally relates to low disk rotational velocity (but not always) while high disk eccentricity always relates to high velocity. There is also the general trend that the disk‐absorption in spectral lines with higher excitation potential comes from disk regions with higher eccentricity and thus also with higher rotational velocity. The dependency on transition probability is more complex and shows a bi‐modal trend. The outskirts of the disk is distributed asymmetrically around the disk and appears to have been built up mostly in a tail along the orbit behind the secondary. Our data show that this tail continues to eclipse the F0 Iab primary star even two years after the end of the photometric eclipse. High‐resolution spectra were also taken of the other, bona‐fide, visual‐binary components of ε Aur (ADS 3605BCDE). Only the C‐component, a K3‐4‐giant, appears at the same distance than ε Aur but its radial velocity is in disagreement with a bound orbit. The other components are a nearby (≈ 7 pc) cool DA white dwarf, a G8 dwarf, and a B9 supergiant, and not related to ε Aur. The cool white dwarf shows strong DIB lines that suggest the existence of a debris disk around this star. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

The Subaru Telescope High Dispersion Spectrograph (HDS)     

W. Aoki 《Astronomische Nachrichten》2014,335(1):27-31

The High Dispersion Spectrograph (HDS) is the échelle spectrograph for an open‐use instrument of the Subaru Telescope. The current status of the instrument is reviewed. The new image slicers that significantly improve the efficiency of observations with very high resolving power have been installed in the past three years. Brief overview of recent science results is given on studies of early generations of stars and extra‐solar planets. An upgrade plan and future prospects of this instrument are discussed. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

FIES: The high‐resolution Fiber‐fed Echelle Spectrograph at the Nordic Optical Telescope     

J.H. Telting  G. Avila  L. Buchhave  S. Frandsen  D. Gandolfi  B. Lindberg  H.C. Stempels  the NOT staff  S. Prins 《Astronomische Nachrichten》2014,335(1):41-45

FIES is a cross‐dispersed high‐resolution echelle spectrograph at the 2.56 m Nordic Optical Telescope (NOT), and was optimised for throughput and stability in 2006. The major 2006 upgrade involved the relocation of FIES to a stable environment and development of a fiber bundle that offers 3 different resolution modes, and made FIES an attractive tool for the user community of the NOT. Radial‐velocity stability is achieved through double‐chamber active temperature control. A dedicated data reduction tool, FIEStool, was developed. As a result of these upgrades, FIES is now one of the work‐horse instruments at the NOT. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

Variable hangingwall palaeotransport during Silurian and Devonian thrusting in the western Lachlan Fold Belt: Missing gold lodes,synchronous Melbourne Trough sedimentation and Grampians Group fold interference     

J. McL. Miller  L. J. Dugdale  C. J. L. Wilson 《Australian Journal of Earth Sciences》2013,60(6):901-909

The western margin of the Lachlan Fold Belt contains early ductile and brittle structures that formed during northeast‐southwest and east‐west compression, followed by reactivation related to sinistral wrenching. At Stawell all of these structural features (and the associated gold lodes) are dismembered by a complex array of later northwest‐, north‐ and northeast‐dipping faults. Detailed underground structural analysis has identified northwest‐trending mid‐Devonian thrusts (Tabberabberan) that post‐date Early Devonian plutonism and have a top‐to‐the‐southwest transport. Deformation associated with the initial stages of dismemberment occurred along an earlier array of faults that trend southwest‐northeast (or east‐west) and dip to the northwest (or north). The initial transport of the units in the hangingwall of these fault structures was top‐to‐the‐southeast. ‘Missing’ gold lodes were discovered beneath the Magdala orebody by reconstructing a displacement history that involved a combination of transport vectors (top‐to‐the‐southeast and top‐to‐the‐southwest). Fold interference structures in the adjacent Silurian Grampians Group provide further evidence for at least two almost orthogonal shortening regimes, post the mid‐Silurian. Overprinting relationships, and correlation with synchronous sedimentation in the Melbourne Trough, indicates that the early fault structures are mid‐ to late‐Silurian in age (Ludlow: ca 420–414 Ma). These atypical southeast‐vergent structures have regional extent and separate significant northeast‐southwest shortening that occurred in the mid‐Devonian (‘Tabberabberan orogeny’) and Late Ordovician (‘Benambran orogeny’).  相似文献