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31.
In this study, we integrated a DNA barcoding project with an ecological survey on intertidal polychaete communities and investigated
the utility of CO1 gene sequence as a DNA barcode for the classification of the intertidal polychaetes. Using 16S rDNA as
a complementary marker and combining morphological and ecological characterization, some of dominant and common polychaete
species from Chinese coasts were assessed for their taxonomic status. We obtained 22 haplotype gene sequences of 13 taxa,
including 10 CO1 sequences and 12 16S rDNA sequences. Based on intra- and inter-specific distances, we built phylogenetic
trees using the neighbor-joining method. Our study suggested that the mitochondrial CO1 gene was a valid DNA barcoding marker
for species identification in polychaetes, but other genes, such as 16S rDNA, could be used as a complementary genetic marker.
For more accurate species identification and effective testing of species hypothesis, DNA barcoding should be incorporated
with morphological, ecological, biogeographical, and phylogenetic information. The application of DNA barcoding and molecular
identification in the ecological survey on the intertidal polychaete communities demonstrated the feasibility of integrating
DNA taxonomy and ecology. 相似文献
32.
由于煤炭开采而形成的塌陷区地形形态复杂,本文利用分形插值理论模拟了塌陷区地形。在Matlab语言环境下,实现了塌陷区基于遗传算法求取无标度区最优解和基于FBM分形插值算法,在此基础上求解分形特征参数H和σ。对概率积分法预计的数据进行分形内插绘制地表下沉图,取得了理想的效果。 相似文献
33.
针对构件外表面局部区域遭受随机点蚀损伤的圆管截面,考虑点蚀随机特性的影响,建立包含点蚀坑细节的精细有限元模型;在多种腐蚀强度下,研究局部腐蚀的点蚀区分布位置(沿轴向和周向分布位置变化)及其形状(点蚀区长度和宽度独立或联合变化)影响轴压极限强度退化的规律;并比较局部随机点蚀与局部均匀腐蚀引起构件极限强度退化的差异。研究结果表明,尽管局部随机点蚀与最大初始几何缺陷的耦合作用会使极限强度的退化趋于严重,但是总体而言点蚀区分布位置变化对圆管极限强度的退化没有显著的影响。此外,同等腐蚀体积和腐蚀面积下,相比于长窄式局部腐蚀,短宽式局部腐蚀会引起更严重的极限强度退化,在严重腐蚀情形下后者导致的强度退化会高出25.5%;相比于局部均匀腐蚀,局部随机点蚀会导致更剧烈的极限强度退化,其不利影响可高出20.7%。 相似文献
34.
改进的热惯量模式及遥感土壤水分 总被引:9,自引:0,他引:9
本文提出一个考虑地表显热通量及潜热通量的热惯量模式。模式利用了地面定标的方法并充分利用了热象图的空间分布信息,因而较大幅度地提高了估算土壤水分含量的精度。 相似文献
35.
The potential information in the temperature difference between shadow and sunlit of surfaces and a new way of retrieving the soil moisture 总被引:3,自引:0,他引:3
ZHANG Renhua SU Hongbo Li Zhaoliang SUN Xiaomin TANG Xinzhai F.Becker 《中国科学D辑(英文版)》2001,44(2):112-123
The thermal inertia and plant water stress index are often adopted to estimate soil moisture available for crops or plants.
However, it is not very easy to obtain two temporal temperatures for thermal inertia model and air temperature for the plant
water stress mode. Shadows of ground objects are often referred to noise on visible and near infrared remote sensing. But
the difference of temperature between shadows and sunlit contains rich information concerning with heat-water status for soil.
This paper presented a new way to excavate just by temperature difference usually between shadow and sunlit surface. Experiments
validated the ideal. We can adopt thermal camera to measure the differences in the field measurements. However, we must use
inversion based on multianglar thermal infrared remote sensing data in airborne and spaceborne. An inverting model was also
presented by using Monte-Carlo and the least square method. Results show that this way is feasible. 相似文献
36.
37.
对于定量热红外遥感的一些思考 总被引:42,自引:4,他引:38
作者根据在热红外遥感工作中的长期实践经验,介绍了热红外遥感的现状,特别指出了定量反演地表温度的难点---地物比辐射率的测定和区域范围内的比辐射率估算。文中提出了定量热红外遥感研究中常见的一些问题。最后,讨论了定量热红外遥感的未来发展趋势和目前现实工作的对策,旨在抛砖引玉,以求得热红外定量遥感的发展。 相似文献
38.
长江三角洲北翼地区缺少较长尺度的第四纪海陆变迁及环境演变的深入探讨,深达423m的海安县基岩标J9孔为此提供了较好的研究对象。通过观察该孔松散层岩芯,总结其沉积特征,认为岩芯明显可划分为6个特征岩性段。同时,地层古地磁测试结果显示: 0~200m为布容正极性世,200~334m为松山负极性世,334m以下为高斯正极性世。综合分析岩芯沉积特征并参考古地磁测试结果对地层进行了初步划分,认为 0~39m为全新世地层,39~153m为晚更新世地层,153~200m为中更新世地层,200~334m为早更新世地层,之下为新近纪地层。从沉积地层特征推测,在第四纪地层中可能存在有5个海侵层,自上而下为第Ⅰ海侵层(镇江海侵)、第Ⅱ海侵层(滆湖海侵)、第Ⅲ海侵层(昆山海侵)、第Ⅳ海侵层(嘉定海侵)和第Ⅴ海侵层(如皋海侵),分别出现在孔深 5~39m段、59.2~85.1m段、121~153m段、171~200m段和 246.3~277.2m段。孔深39~41m存在的晚更新世晚期特征硬粘土标志层,指示本地不是冰后期古河谷的发育地。 相似文献
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40.
It is more and more popular to estimate the exchange of water vapor, heat and CO2fluxes between the land surface and the atmosphere using the eddy covariance technique. To get believable fluxes, it is necessary to correct the observations based on the different surface conditions and to determine relevant techinical parameters. The raw 10 Hz eddy covariance data observed in the Yucheng and Changbai Mountains stations were recalculated by various averaging periods (from 1 to 720 min) respectively, and the recalculated results were compared with the results calculated by the averaging period of 30 mins. Meanwhile, the distinctions of fluxes calculated by different averaging periods were analyzed. The continuous 15 days observations over wheat fields in the Yucheng station were mainly analyzed. The results are shown that: (i) In the Yucheng station, compared with the observations by 30 min, when the averaging period changes from 10 to 60 min, the variations of the eddy-covariance estimates of fluxes were less than 2%; when the averaging period changes less than 10 min, the estimate of fluxes reduced obviously with the reduction of the averaging period (the max relative error was -12%); and when the averaging period exceeds 120 min, the eddy covariance estimates of fluxes will be increased and become unsteady (the max relative error is over 10%); (ii) the eddy covariance estimates of fluxes over wheat field in the Yucheng station suggusted that it is much better to take 10 min as an averaging period in studying diurnal change of fluxes, and take 30min for a long-term flux observation; and (iii) normalized ratio was put forward to determine the range of averaging period of eddy covariance measurements. By comparing the observations over farmlands and those over forests, it is indicated that the increase of eddy covariance estimates over tall forest was more than that over short vegetation when the averaging period increased. 相似文献