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51.
华南中-新生代构造演化受太平洋构造域和特提斯洋构造域的联合控制.以江南东段NE-SW向景德镇-歙县剪切带和球川-萧山断裂中发育的脆性断层为研究对象,利用野外交切关系和断层滑移矢量反演方法厘定了7期构造变形序列并反演了各期古构造应力场,讨论了断层活动的时代及其动力学.白垩纪至新生代研究区7期古构造应力场分别为:(1)早白垩世早期(136~125Ma)NW-SE向伸展;(2)早白垩世晚期(125~107Ma)N-S向挤压和E-W向伸展;(3)早白垩世末期至晚白垩世早期(105~86Ma)NW-SE向伸展;(4)白垩世中期(86~80Ma)NW-SE向挤压和NE-SW向伸展;(5)晚白垩世晚期至始新世末期(80~36Ma)N-S向伸展;(6)始新世末期至渐新世早期(36~30Ma)NE-SW向挤压和NW-SE向伸展;(7)渐新世早期至中新世中期(30~17Ma)NE-SW向伸展.结合区域地质研究表明,第1期至第4期古构造应力场与古太平洋构造域的板片后撤、俯冲以及微块体(菲律宾地块)间的碰撞作用有关;第5期伸展作用受控于新特提斯构造域俯冲板片后撤,而第6期和第7期古构造应力场主要与印-亚碰撞的远程效应有关.白垩纪至新生代,华南东部受伸展构造体制和走滑构造体制的交替控制.先存断裂的发育可能是导致华南晚中生代走滑构造体制的主要控制因素. 相似文献
52.
Xiaoli Liu Linbao Zhang Liping You Huifeng Wu Jianmin Zhao Ming Cong Fei Li Qing Wang Lianzhen Li Chenghua Li Guangxuan Han Guangmei Wang Chuanhai Xia Junbao Yu 《洁净——土壤、空气、水》2011,39(8):720-727
Plant metabolomics has been well established and applied across multiple fields including medicine, biotechnology, and environmental sciences in the post‐genomic era. The Chenopodiaceae C3 halophyte Suaeda salsa is the most important plant species in the vegetation of saline soil and even intertidal zone in the Yellow River Delta, which is economically consumed as food, widely used as a bioindicator of environmental stresses (salinity, drought, and pollution) and typically applied for the phyto‐remediation of degraded wetland. However, no global studies have been focused on the metabolic profile of this halophyte which is widely applied in environment related research areas. In metabolomics, the first crucial step is the preparation of plant samples. In this work, several strategies of metabolite extraction from this C3 halophytes S. salsa were evaluated and the metabolic profile was characterized by NMR‐based metabolomics. Multiple replicates of plant tissues (approx. 250 mg whole fresh weight of leaves and stems) were homogenized by a high throughput automated Precellys 24 bead‐based homogenizer and then extracted using the following solvent systems of varying polarities: methanol, water, methanol/water, methanol/chloroform/water, and acetonitrile. The hydrophilic metabolites were analyzed using one‐dimensional proton NMR spectroscopy, and the subsequent NMR spectra were evaluated by principal components analysis (PCA). Each extraction protocol revealed unique metabolic profile from S. salsa. Overall, the quality of each extraction protocol was assessed based on the yield, reproducibility, ease, and speed, and we concluded that the solvent of methanol/water was preferable for the metabolite extraction due to its highest reproducibility, ease, and speed, and considerably high yield. Validation of methanol/water (1:1) solvent also showed a high degree of reproducibility with technical variation being considerably lower than biological variation in S. salsa samples. This demonstrated the quality and robustness of the methanol/water extraction method for NMR‐based metabolomics studies. 相似文献
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54.
根据青藏高原GPS实测数据,讨论了“SA”和“AS”技术对GPS精密大地测量的影响。认为“SA”和“AS”技术对静态单点定位精度的影响是严重的,不能单纯依赖延长观测时间来提高其精度;它们还将使载波相位测量精度有所下降;对载波相位测量差分法无甚影响,但必须设法获得起算点在WGS84坐标系中具有一定精度的坐标。最后提出了相应的解决途径 相似文献
55.
为了准确规划和评价南京汤山地区地热水资源的可开采量,预测在规划开采条件下的地热水水位和水温的变化,在充分研究了汤山地区地热水系统水文地质特征的基础上,概化出南京汤山地区地热水系统的水文地质概念模型,建立了地热水非稳定渗流和热量运移三维耦合数学模型,模拟预测了降深不超过50 m时的地热水可开采量及其水位和水温的变化。结果表明:汤山地区现有14口地热水井的可开采量有所差异,最大为R08(温泉公司1#),开采量可达1 450.0 m3/d,最小为R11(中闻集团2#),开采量仅有125.0 m3/d,地热水的总可开采量为3.08×106m3/a;且随着开采的进行,地热水水位逐渐下降,各地热水井温度逐渐上升,上升幅度略有不同,年均水温上升2~3℃。 相似文献
56.
In this study, we create and critically analyse an automated decision tree classification approach for regional level land cover mapping in insular South-East Asian conditions, using a combination of 10–30 m resolution optical and radar data. The resulting map contains 11 land cover classes and reveals a great deal of contextual information due to high spatial resolution. A limited accuracy assessment indicates 59–97% class wise accuracies. The unprecedented spatial detail of closed canopy oil palm mapping (with user’s accuracy of 90%) is seen as the most promising feature of the mapping approach. The incapability of separating primary forests from other tree cover, and the large variety of different landscapes (e.g. home gardens and tea plantations) classified as shrubland, are considered the main areas for future improvement. Overall, the study demonstrates the great potential of multi-source 10–30 m resolution high data volume land cover mapping approaches in insular South-East Asian conditions. 相似文献
57.
土坡有限元稳定分析若干问题探讨 总被引:40,自引:5,他引:35
详细探讨了用有限元方法分析土坡稳定所遇到的问题及处理方法 ,主要包括: 有限元前后处理 ;有限元计算范围及网格划分对计算结果的影响 ;安全系数的定义 ;最危险滑动圆心位置及临界滑动面的形状等问题。 相似文献
58.
59.
YAN Chenghua 《中国海洋工程》2001,(2):291-300
A two-dimensional nonlinear sloshing problem is analyzed by means of the fully nonlinear theory and time domain second order theory of water waves. Liquid sloshing in a rectangular container subjected to a horizontal excitation is sim-ulated by the finite element method. Comparisons between the two theories are made based on their numerical results, It is found that good agreement is obtained for the case of small amplitude oscillation and obvious differences occur for large amplitude excitation. Even though, the second order solution can still exhibit typical nonlinear features of nonlinear wave and can be used instead of the fully nonlinear theory. 相似文献
60.
用适宜于四川地区的太阳总辐射计算方法,计算了涪江流域近年来的太阳总辐射量。并用彭曼公式求出涪江流域近年来和绵阳42年的水资源变化。提出了近几年涪江流域水资源处于历史低值期、太阳总辐射处于历史高值期;水资源短缺期由历史上的6~7个月增加到近几年的9~10个月等观点。为合理利用涪江流域水资源、科学安排工农业及生活用水提供了理论依据。 相似文献